System.Data.SQLite

/******************************************************************************
** This file is an amalgamation of many separate C source files from SQLite
** version 3.7.10.  By combining all the individual C code files into this 
** single large file, the entire code can be compiled as a single translation
** unit.  This allows many compilers to do optimizations that would not be
** possible if the files were compiled separately.  Performance improvements
** of 5% or more are commonly seen when SQLite is compiled as a single
** translation unit.
**
** This file is all you need to compile SQLite.  To use SQLite in other

#if defined(THREADSAFE)
# define SQLITE_THREADSAFE THREADSAFE
#else
# define SQLITE_THREADSAFE 1 /* IMP: R-07272-22309 */
#endif
#endif

/*
** Powersafe overwrite is on by default.  But can be turned off using
** the -DSQLITE_POWERSAFE_OVERWRITE=0 command-line option.
*/
#ifndef SQLITE_POWERSAFE_OVERWRITE
# define SQLITE_POWERSAFE_OVERWRITE 1
#endif

/*
** The SQLITE_DEFAULT_MEMSTATUS macro must be defined as either 0 or 1.
** It determines whether or not the features related to 
** SQLITE_CONFIG_MEMSTATUS are available by default or not. This value can
** be overridden at runtime using the sqlite3_config() API.
*/
#if !defined(SQLITE_DEFAULT_MEMSTATUS)

** string contains the date and time of the check-in (UTC) and an SHA1
** hash of the entire source tree.
**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.7.10"
#define SQLITE_VERSION_NUMBER 3007010
#define SQLITE_SOURCE_ID      "2012-01-12 16:41:30 a298465c3919c331b9d8b60351c42b96d2efacdc"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version, sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

SQLITE_API const char *sqlite3_compileoption_get(int N);
#endif

/*
** CAPI3REF: Test To See If The Library Is Threadsafe
**
** ^The sqlite3_threadsafe() function returns zero if and only if
** SQLite was compiled with mutexing code omitted due to the
** [SQLITE_THREADSAFE] compile-time option being set to 0.
**
** SQLite can be compiled with or without mutexes.  When
** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
** are enabled and SQLite is threadsafe.  When the
** [SQLITE_THREADSAFE] macro is 0, 
** the mutexes are omitted.  Without the mutexes, it is not safe

/*
** CAPI3REF: Result Codes
** KEYWORDS: SQLITE_OK {error code} {error codes}
** KEYWORDS: {result code} {result codes}
**
** Many SQLite functions return an integer result code from the set shown
** here in order to indicate success or failure.
**
** New error codes may be added in future versions of SQLite.
**
** See also: [SQLITE_IOERR_READ | extended result codes],
** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].
*/
#define SQLITE_OK           0   /* Successful result */

** mean that writes of blocks that are nnn bytes in size and
** are aligned to an address which is an integer multiple of
** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
** that when data is appended to a file, the data is appended
** first then the size of the file is extended, never the other
** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
** information is written to disk in the same order as calls
** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
** after reboot following a crash or power loss, the only bytes in a
** file that were written at the application level might have changed
** and that adjacent bytes, even bytes within the same sector are
** guaranteed to be unchanged.
*/
#define SQLITE_IOCAP_ATOMIC                 0x00000001
#define SQLITE_IOCAP_ATOMIC512              0x00000002
#define SQLITE_IOCAP_ATOMIC1K               0x00000004
#define SQLITE_IOCAP_ATOMIC2K               0x00000008
#define SQLITE_IOCAP_ATOMIC4K               0x00000010
#define SQLITE_IOCAP_ATOMIC8K               0x00000020
#define SQLITE_IOCAP_ATOMIC16K              0x00000040
#define SQLITE_IOCAP_ATOMIC32K              0x00000080
#define SQLITE_IOCAP_ATOMIC64K              0x00000100
#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000

/*
** CAPI3REF: File Locking Levels
**
** SQLite uses one of these integer values as the second
** argument to calls it makes to the xLock() and xUnlock() methods
** of an [sqlite3_io_methods] object.

** VFSes do not need this signal and should silently ignore this opcode.
** Applications should not call [sqlite3_file_control()] with this
** opcode as doing so may disrupt the operation of the specialized VFSes
** that do require it.  
**
** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
** retry counts and intervals for certain disk I/O operations for the
** windows [VFS] in order to provide robustness in the presence of
** anti-virus programs.  By default, the windows VFS will retry file read,
** file write, and file delete operations up to 10 times, with a delay
** of 25 milliseconds before the first retry and with the delay increasing
** by an additional 25 milliseconds with each subsequent retry.  This
** opcode allows these two values (10 retries and 25 milliseconds of delay)
** to be adjusted.  The values are changed for all database connections
** within the same process.  The argument is a pointer to an array of two
** integers where the first integer i the new retry count and the second
** integer is the delay.  If either integer is negative, then the setting
** is not changed but instead the prior value of that setting is written
** into the array entry, allowing the current retry settings to be
** interrogated.  The zDbName parameter is ignored.

** have write permission on the directory containing the database file want
** to read the database file, as the WAL and shared memory files must exist
** in order for the database to be readable.  The fourth parameter to
** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
** WAL mode.  If the integer is -1, then it is overwritten with the current
** WAL persistence setting.
**
** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
** xDeviceCharacteristics methods. The fourth parameter to
** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
** mode.  If the integer is -1, then it is overwritten with the current
** zero-damage mode setting.
**
** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
** a write transaction to indicate that, unless it is rolled back for some
** reason, the entire database file will be overwritten by the current 
** transaction. This is used by VACUUM operations.
**
** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
** final bottom-level VFS are written into memory obtained from 
** [sqlite3_malloc()] and the result is stored in the char* variable
** that the fourth parameter of [sqlite3_file_control()] points to.
** The caller is responsible for freeing the memory when done.  As with
** all file-control actions, there is no guarantee that this will actually
** do anything.  Callers should initialize the char* variable to a NULL
** pointer in case this file-control is not implemented.  This file-control
** is intended for diagnostic use only.
*/
#define SQLITE_FCNTL_LOCKSTATE               1
#define SQLITE_GET_LOCKPROXYFILE             2
#define SQLITE_SET_LOCKPROXYFILE             3
#define SQLITE_LAST_ERRNO                    4
#define SQLITE_FCNTL_SIZE_HINT               5
#define SQLITE_FCNTL_CHUNK_SIZE              6
#define SQLITE_FCNTL_FILE_POINTER            7
#define SQLITE_FCNTL_SYNC_OMITTED            8
#define SQLITE_FCNTL_WIN32_AV_RETRY          9
#define SQLITE_FCNTL_PERSIST_WAL            10
#define SQLITE_FCNTL_OVERWRITE              11
#define SQLITE_FCNTL_VFSNAME                12
#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13

/*
** CAPI3REF: Mutex Handle
**
** The mutex module within SQLite defines [sqlite3_mutex] to be an
** abstract type for a mutex object.  The SQLite core never looks
** at the internal representation of an [sqlite3_mutex].  It only

**
** [[sqlite3_vfs.xOpen]]
** ^SQLite guarantees that the zFilename parameter to xOpen
** is either a NULL pointer or string obtained
** from xFullPathname() with an optional suffix added.
** ^If a suffix is added to the zFilename parameter, it will
** consist of a single "-" character followed by no more than
** 11 alphanumeric and/or "-" characters.
** ^SQLite further guarantees that
** the string will be valid and unchanged until xClose() is
** called. Because of the previous sentence,
** the [sqlite3_file] can safely store a pointer to the
** filename if it needs to remember the filename for some reason.
** If the zFilename parameter to xOpen is a NULL pointer then xOpen
** must invent its own temporary name for the file.  ^Whenever the 

** scratch memory beyond what is provided by this configuration option, then 
** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>
**
** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
** <dd> ^This option specifies a static memory buffer that SQLite can use for
** the database page cache with the default page cache implementation.  
** This configuration should not be used if an application-define page
** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.
** There are three arguments to this option: A pointer to 8-byte aligned
** memory, the size of each page buffer (sz), and the number of pages (N).
** The sz argument should be the size of the largest database page
** (a power of two between 512 and 32768) plus a little extra for each
** page header.  ^The page header size is 20 to 40 bytes depending on
** the host architecture.  ^It is harmless, apart from the wasted memory,
** to make sz a little too large.  The first

** [database connection].  The first argument is the
** size of each lookaside buffer slot and the second is the number of
** slots allocated to each database connection.)^  ^(This option sets the
** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
** verb to [sqlite3_db_config()] can be used to change the lookaside
** configuration on individual connections.)^ </dd>
**
** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
** <dd> ^(This option takes a single argument which is a pointer to
** an [sqlite3_pcache_methods2] object.  This object specifies the interface
** to a custom page cache implementation.)^  ^SQLite makes a copy of the
** object and uses it for page cache memory allocations.</dd>
**
** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
** <dd> ^(This option takes a single argument which is a pointer to an
** [sqlite3_pcache_methods2] object.  SQLite copies of the current
** page cache implementation into that object.)^ </dd>
**
** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
** function with a call signature of void(*)(void*,int,const char*), 
** and a pointer to void. ^If the function pointer is not NULL, it is
** invoked by [sqlite3_log()] to process each logging event.  ^If the

** specified as part of [ATTACH] commands are interpreted as URIs, regardless
** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
** connection is opened. If it is globally disabled, filenames are
** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
** database connection is opened. By default, URI handling is globally
** disabled. The default value may be changed by compiling with the
** [SQLITE_USE_URI] symbol defined.
**
** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFNIG_GETPCACHE
** <dd> These options are obsolete and should not be used by new code.
** They are retained for backwards compatibility but are now no-ops.
** </dl>
*/
#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
#define SQLITE_CONFIG_PCACHE       14  /* no-op */
#define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
#define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
#define SQLITE_CONFIG_URI          17  /* int */
#define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
#define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */

/*
** CAPI3REF: Database Connection Configuration Options
**
** These constants are the available integer configuration options that
** can be passed as the second argument to the [sqlite3_db_config()] interface.
**

** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
**
** These routines all implement some additional formatting
** options that are useful for constructing SQL statements.
** All of the usual printf() formatting options apply.  In addition, there
** is are "%q", "%Q", and "%z" options.
**
** ^(The %q option works like %s in that it substitutes a nul-terminated
** string from the argument list.  But %q also doubles every '\'' character.
** %q is designed for use inside a string literal.)^  By doubling each '\''
** character it escapes that character and allows it to be inserted into
** the string.
**
** For example, assume the string variable zText contains text as follows:
**

  int flags,              /* Flags */
  const char *zVfs        /* Name of VFS module to use */
);

/*
** CAPI3REF: Obtain Values For URI Parameters
**
** These are utility routines, useful to VFS implementations, that check
** to see if a database file was a URI that contained a specific query 
** parameter, and if so obtains the value of that query parameter.
**
** If F is the filename pointer passed into the xOpen() method of a VFS
** implementation and P is the name of the query parameter, then
** sqlite3_uri_parameter(F,P) returns the value of the P
** parameter if it exists or a NULL pointer if P does not appear as a 
** query parameter on F.  If P is a query parameter of F
** has no explicit value, then sqlite3_uri_parameter(F,P) returns
** a pointer to an empty string.
**
** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
** parameter and returns true (1) or false (0) according to the value
** of P.  The value of P is true if it is "yes" or "true" or "on" or 
** a non-zero number and is false otherwise.  If P is not a query parameter
** on F then sqlite3_uri_boolean(F,P,B) returns (B!=0).
**
** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
** 64-bit signed integer and returns that integer, or D if P does not
** exist.  If the value of P is something other than an integer, then
** zero is returned.
** 
** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
** is not a pathname pointer that SQLite passed into the xOpen VFS method,
** then the behavior of this routine is undefined and probably undesirable.
*/
SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);


/*
** CAPI3REF: Error Codes And Messages
**
** ^The sqlite3_errcode() interface returns the numeric [result code] or
** [extended result code] for the most recent failed sqlite3_* API call

** database.  ^The [ATTACH] and [DETACH] statements also cause
** sqlite3_stmt_readonly() to return true since, while those statements
** change the configuration of a database connection, they do not make 
** changes to the content of the database files on disk.
*/
SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Determine If A Prepared Statement Has Been Reset
**
** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
** [prepared statement] S has been stepped at least once using 
** [sqlite3_step(S)] but has not run to completion and/or has not 
** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
** interface returns false if S is a NULL pointer.  If S is not a 
** NULL pointer and is not a pointer to a valid [prepared statement]
** object, then the behavior is undefined and probably undesirable.
**
** This interface can be used in combination [sqlite3_next_stmt()]
** to locate all prepared statements associated with a database 
** connection that are in need of being reset.  This can be used,
** for example, in diagnostic routines to search for prepared 
** statements that are holding a transaction open.
*/
SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);

/*
** CAPI3REF: Dynamically Typed Value Object
** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
**
** SQLite uses the sqlite3_value object to represent all values
** that can be stored in a database table. SQLite uses dynamic typing
** for the values it stores.  ^Values stored in sqlite3_value objects

** ^The values returned by [sqlite3_column_bytes()] and 
** [sqlite3_column_bytes16()] do not include the zero terminators at the end
** of the string.  ^For clarity: the values returned by
** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
** bytes in the string, not the number of characters.
**
** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
** even empty strings, are always zero-terminated.  ^The return
** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
**
** ^The object returned by [sqlite3_column_value()] is an
** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
** If the [unprotected sqlite3_value] object returned by
** [sqlite3_column_value()] is used in any other way, including calls

** returned by sqlite3_db_handle is the same [database connection]
** that was the first argument
** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
** create the statement in the first place.
*/
SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);

/*
** CAPI3REF: Return The Filename For A Database Connection
**
** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
** associated with database N of connection D.  ^The main database file
** has the name "main".  If there is no attached database N on the database
** connection D, or if database N is a temporary or in-memory database, then
** a NULL pointer is returned.
**
** ^The filename returned by this function is the output of the
** xFullPathname method of the [VFS].  ^In other words, the filename
** will be an absolute pathname, even if the filename used
** to open the database originally was a URI or relative pathname.
*/
SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);

/*
** CAPI3REF: Find the next prepared statement
**
** ^This interface returns a pointer to the next [prepared statement] after
** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
** then this interface returns a pointer to the first prepared statement
** associated with the database connection pDb.  ^If no prepared statement

** then the commit is converted into a rollback.
**
** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
** return the P argument from the previous call of the same function
** on the same [database connection] D, or NULL for
** the first call for each function on D.
**
** The commit and rollback hook callbacks are not reentrant.
** The callback implementation must not do anything that will modify
** the database connection that invoked the callback.  Any actions
** to modify the database connection must be deferred until after the
** completion of the [sqlite3_step()] call that triggered the commit
** or rollback hook in the first place.
** Note that running any other SQL statements, including SELECT statements,
** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
** the database connections for the meaning of "modify" in this paragraph.
**
** ^Registering a NULL function disables the callback.
**
** ^When the commit hook callback routine returns zero, the [COMMIT]
** operation is allowed to continue normally.  ^If the commit hook
** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
** ^The rollback hook is invoked on a rollback that results from a commit

** of heap memory by deallocating non-essential memory allocations
** held by the database library.   Memory used to cache database
** pages to improve performance is an example of non-essential memory.
** ^sqlite3_release_memory() returns the number of bytes actually freed,
** which might be more or less than the amount requested.
** ^The sqlite3_release_memory() routine is a no-op returning zero
** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
**
** See also: [sqlite3_db_release_memory()]
*/
SQLITE_API int sqlite3_release_memory(int);

/*
** CAPI3REF: Free Memory Used By A Database Connection
**
** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
** memory as possible from database connection D. Unlike the
** [sqlite3_release_memory()] interface, this interface is effect even
** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
** omitted.
**
** See also: [sqlite3_release_memory()]
*/
SQLITE_API int sqlite3_db_release_memory(sqlite3*);

/*
** CAPI3REF: Impose A Limit On Heap Size
**
** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
** soft limit on the amount of heap memory that may be allocated by SQLite.
** ^SQLite strives to keep heap memory utilization below the soft heap
** limit by reducing the number of pages held in the page cache
** as heap memory usages approaches the limit.
** ^The soft heap limit is "soft" because even though SQLite strives to stay
** below the limit, it will exceed the limit rather than generate
** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
** is advisory only.
**
** ^The return value from sqlite3_soft_heap_limit64() is the size of
** the soft heap limit prior to the call, or negative in the case of an
** error.  ^If the argument N is negative
** then no change is made to the soft heap limit.  Hence, the current
** size of the soft heap limit can be determined by invoking
** sqlite3_soft_heap_limit64() with a negative argument.
**
** ^If the argument N is zero then the soft heap limit is disabled.
**
** ^(The soft heap limit is not enforced in the current implementation
** if one or more of following conditions are true:
**
** <ul>
** <li> The soft heap limit is set to zero.
** <li> Memory accounting is disabled using a combination of the
**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
** <li> An alternative page cache implementation is specified using
**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
** <li> The page cache allocates from its own memory pool supplied
**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
**      from the heap.
** </ul>)^
**
** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]

** The SQLite source code contains multiple implementations
** of these mutex routines.  An appropriate implementation
** is selected automatically at compile-time.  ^(The following
** implementations are available in the SQLite core:
**
** <ul>
** <li>   SQLITE_MUTEX_OS2
** <li>   SQLITE_MUTEX_PTHREADS
** <li>   SQLITE_MUTEX_W32
** <li>   SQLITE_MUTEX_NOOP
** </ul>)^
**
** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
** that does no real locking and is appropriate for use in
** a single-threaded application.  ^The SQLITE_MUTEX_OS2,
** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations
** are appropriate for use on OS/2, Unix, and Windows.
**
** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
** implementation is included with the library. In this case the
** application must supply a custom mutex implementation using the
** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function

** with the SQLITE_DEBUG flag.  ^External mutex implementations
** are only required to provide these routines if SQLITE_DEBUG is
** defined and if NDEBUG is not defined.
**
** ^These routines should return true if the mutex in their argument
** is held or not held, respectively, by the calling thread.
**
** ^The implementation is not required to provide versions of these
** routines that actually work. If the implementation does not provide working
** versions of these routines, it should at least provide stubs that always
** return true so that one does not get spurious assertion failures.
**
** ^If the argument to sqlite3_mutex_held() is a NULL pointer then
** the routine should return 1.   This seems counter-intuitive since
** clearly the mutex cannot be held if it does not exist.  But

#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
#define SQLITE_TESTCTRL_PENDING_BYTE            11
#define SQLITE_TESTCTRL_ASSERT                  12
#define SQLITE_TESTCTRL_ALWAYS                  13
#define SQLITE_TESTCTRL_RESERVE                 14
#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
#define SQLITE_TESTCTRL_ISKEYWORD               16

#define SQLITE_TESTCTRL_SCRATCHMALLOC           17
#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
#define SQLITE_TESTCTRL_EXPLAIN_STMT            19
#define SQLITE_TESTCTRL_LAST                    19

/*
** CAPI3REF: SQLite Runtime Status
**
** ^This interface is used to retrieve runtime status information
** about the performance of SQLite, and optionally to reset various

**
** The sqlite3_pcache type is opaque.  It is implemented by
** the pluggable module.  The SQLite core has no knowledge of
** its size or internal structure and never deals with the
** sqlite3_pcache object except by holding and passing pointers
** to the object.
**
** See [sqlite3_pcache_methods2] for additional information.
*/
typedef struct sqlite3_pcache sqlite3_pcache;

/*
** CAPI3REF: Custom Page Cache Object
**
** The sqlite3_pcache_page object represents a single page in the
** page cache.  The page cache will allocate instances of this
** object.  Various methods of the page cache use pointers to instances
** of this object as parameters or as their return value.
**
** See [sqlite3_pcache_methods2] for additional information.
*/
typedef struct sqlite3_pcache_page sqlite3_pcache_page;
struct sqlite3_pcache_page {
  void *pBuf;        /* The content of the page */
  void *pExtra;      /* Extra information associated with the page */
};

/*
** CAPI3REF: Application Defined Page Cache.
** KEYWORDS: {page cache}
**
** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
** register an alternative page cache implementation by passing in an 
** instance of the sqlite3_pcache_methods2 structure.)^
** In many applications, most of the heap memory allocated by 
** SQLite is used for the page cache.
** By implementing a 
** custom page cache using this API, an application can better control
** the amount of memory consumed by SQLite, the way in which 
** that memory is allocated and released, and the policies used to 
** determine exactly which parts of a database file are cached and for 
** how long.
**
** The alternative page cache mechanism is an
** extreme measure that is only needed by the most demanding applications.
** The built-in page cache is recommended for most uses.
**
** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
** internal buffer by SQLite within the call to [sqlite3_config].  Hence
** the application may discard the parameter after the call to
** [sqlite3_config()] returns.)^
**
** [[the xInit() page cache method]]
** ^(The xInit() method is called once for each effective 
** call to [sqlite3_initialize()])^
** (usually only once during the lifetime of the process). ^(The xInit()
** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
** The intent of the xInit() method is to set up global data structures 
** required by the custom page cache implementation. 
** ^(If the xInit() method is NULL, then the 
** built-in default page cache is used instead of the application defined
** page cache.)^
**
** [[the xShutdown() page cache method]]

** call to xShutdown().
**
** [[the xCreate() page cache methods]]
** ^SQLite invokes the xCreate() method to construct a new cache instance.
** SQLite will typically create one cache instance for each open database file,
** though this is not guaranteed. ^The
** first parameter, szPage, is the size in bytes of the pages that must
** be allocated by the cache.  ^szPage will always a power of two.  ^The
** second parameter szExtra is a number of bytes of extra storage 
** associated with each page cache entry.  ^The szExtra parameter will
** a number less than 250.  SQLite will use the
** extra szExtra bytes on each page to store metadata about the underlying
** database page on disk.  The value passed into szExtra depends
** on the SQLite version, the target platform, and how SQLite was compiled.



** ^The third argument to xCreate(), bPurgeable, is true if the cache being
** created will be used to cache database pages of a file stored on disk, or
** false if it is used for an in-memory database. The cache implementation
** does not have to do anything special based with the value of bPurgeable;
** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
** never invoke xUnpin() except to deliberately delete a page.
** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
** false will always have the "discard" flag set to true.  
** ^Hence, a cache created with bPurgeable false will

**
** [[the xPagecount() page cache methods]]
** The xPagecount() method must return the number of pages currently
** stored in the cache, both pinned and unpinned.
** 
** [[the xFetch() page cache methods]]
** The xFetch() method locates a page in the cache and returns a pointer to 
** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
** The pBuf element of the returned sqlite3_pcache_page object will be a
** pointer to a buffer of szPage bytes used to store the content of a 
** single database page.  The pExtra element of sqlite3_pcache_page will be
** a pointer to the szExtra bytes of extra storage that SQLite has requested
** for each entry in the page cache.
**
** The page to be fetched is determined by the key. ^The minimum key value
** is 1.  After it has been retrieved using xFetch, the page is considered
** to be "pinned".
**
** If the requested page is already in the page cache, then the page cache
** implementation must return a pointer to the page buffer with its content
** intact.  If the requested page is not already in the cache, then the
** cache implementation should use the value of the createFlag
** parameter to help it determined what action to take:
**

** of these pages are pinned, they are implicitly unpinned, meaning that
** they can be safely discarded.
**
** [[the xDestroy() page cache method]]
** ^The xDestroy() method is used to delete a cache allocated by xCreate().
** All resources associated with the specified cache should be freed. ^After
** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
** handle invalid, and will not use it with any other sqlite3_pcache_methods2
** functions.
**
** [[the xShrink() page cache method]]
** ^SQLite invokes the xShrink() method when it wants the page cache to
** free up as much of heap memory as possible.  The page cache implementation
** is not obligated to free any memory, but well-behaved implementions should
** do their best.
*/
typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
struct sqlite3_pcache_methods2 {
  int iVersion;
  void *pArg;
  int (*xInit)(void*);
  void (*xShutdown)(void*);
  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
  int (*xPagecount)(sqlite3_pcache*);
  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 
      unsigned oldKey, unsigned newKey);
  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
  void (*xDestroy)(sqlite3_pcache*);
  void (*xShrink)(sqlite3_pcache*);
};

/*
** This is the obsolete pcache_methods object that has now been replaced
** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
** retained in the header file for backwards compatibility only.
*/
typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
struct sqlite3_pcache_methods {
  void *pArg;
  int (*xInit)(void*);
  void (*xShutdown)(void*);
  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
  int (*xPagecount)(sqlite3_pcache*);
  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
  void (*xDestroy)(sqlite3_pcache*);
};


/*
** CAPI3REF: Online Backup Object
**
** The sqlite3_backup object records state information about an ongoing
** online backup operation.  ^The sqlite3_backup object is created by
** a call to [sqlite3_backup_init()] and is destroyed by a call to

** The "file format" number is an integer that is incremented whenever
** the VDBE-level file format changes.  The following macros define the
** the default file format for new databases and the maximum file format
** that the library can read.
*/
#define SQLITE_MAX_FILE_FORMAT 4
#ifndef SQLITE_DEFAULT_FILE_FORMAT
# define SQLITE_DEFAULT_FILE_FORMAT 4
#endif

/*
** Determine whether triggers are recursive by default.  This can be
** changed at run-time using a pragma.
*/
#ifndef SQLITE_DEFAULT_RECURSIVE_TRIGGERS

** A sub-routine used to implement a trigger program.
*/
struct SubProgram {
  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
  int nOp;                      /* Elements in aOp[] */
  int nMem;                     /* Number of memory cells required */
  int nCsr;                     /* Number of cursors required */
  int nOnce;                    /* Number of OP_Once instructions */
  void *token;                  /* id that may be used to recursive triggers */
  SubProgram *pNext;            /* Next sub-program already visited */
};

/*
** A smaller version of VdbeOp used for the VdbeAddOpList() function because
** it takes up less space.

#define OPFLG_OUT2_PRERELEASE 0x0002  /* out2-prerelease: */
#define OPFLG_IN1             0x0004  /* in1:   P1 is an input */
#define OPFLG_IN2             0x0008  /* in2:   P2 is an input */
#define OPFLG_IN3             0x0010  /* in3:   P3 is an input */
#define OPFLG_OUT2            0x0020  /* out2:  P2 is an output */
#define OPFLG_OUT3            0x0040  /* out3:  P3 is an output */
#define OPFLG_INITIALIZER {\
/*   0 */ 0x00, 0x01, 0x01, 0x04, 0x04, 0x10, 0x00, 0x02,\
/*   8 */ 0x02, 0x02, 0x02, 0x02, 0x02, 0x00, 0x24, 0x24,\
/*  16 */ 0x00, 0x00, 0x00, 0x24, 0x04, 0x05, 0x04, 0x00,\
/*  24 */ 0x00, 0x01, 0x01, 0x05, 0x05, 0x00, 0x00, 0x00,\
/*  32 */ 0x02, 0x00, 0x00, 0x00, 0x02, 0x10, 0x00, 0x00,\
/*  40 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x11, 0x11,\
/*  48 */ 0x11, 0x11, 0x08, 0x11, 0x11, 0x11, 0x11, 0x02,\
/*  56 */ 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
/*  64 */ 0x00, 0x02, 0x00, 0x01, 0x4c, 0x4c, 0x01, 0x01,\
/*  72 */ 0x01, 0x05, 0x05, 0x15, 0x15, 0x15, 0x15, 0x15,\
/*  80 */ 0x15, 0x01, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c, 0x4c,\

SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);

/* Functions used to configure a Pager object. */
SQLITE_PRIVATE void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *);
SQLITE_PRIVATE int sqlite3PagerSetPagesize(Pager*, u32*, int);
SQLITE_PRIVATE int sqlite3PagerMaxPageCount(Pager*, int);
SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager*, int);
SQLITE_PRIVATE void sqlite3PagerShrink(Pager*);
SQLITE_PRIVATE void sqlite3PagerSetSafetyLevel(Pager*,int,int,int);
SQLITE_PRIVATE int sqlite3PagerLockingMode(Pager *, int);
SQLITE_PRIVATE int sqlite3PagerSetJournalMode(Pager *, int);
SQLITE_PRIVATE int sqlite3PagerGetJournalMode(Pager*);
SQLITE_PRIVATE int sqlite3PagerOkToChangeJournalMode(Pager*);
SQLITE_PRIVATE i64 sqlite3PagerJournalSizeLimit(Pager *, i64);
SQLITE_PRIVATE sqlite3_backup **sqlite3PagerBackupPtr(Pager*);

typedef struct PCache PCache;

/*
** Every page in the cache is controlled by an instance of the following
** structure.
*/
struct PgHdr {
  sqlite3_pcache_page *pPage;    /* Pcache object page handle */
  void *pData;                   /* Page data */
  void *pExtra;                  /* Extra content */
  PgHdr *pDirty;                 /* Transient list of dirty pages */
  Pgno pgno;                     /* Page number for this page */
  Pager *pPager;                 /* The pager this page is part of */
#ifdef SQLITE_CHECK_PAGES
  u32 pageHash;                  /* Hash of page content */
#endif

** of the suggested cache-sizes.
*/
SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *, int);
#ifdef SQLITE_TEST
SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *);
#endif

/* Free up as much memory as possible from the page cache */
SQLITE_PRIVATE void sqlite3PcacheShrink(PCache*);

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/* Try to return memory used by the pcache module to the main memory heap */
SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int);
#endif

#ifdef SQLITE_TEST
SQLITE_PRIVATE void sqlite3PcacheStats(int*,int*,int*,int*);

#  define SQLITE_OS_OS2 0
# endif
#else
# ifndef SQLITE_OS_WIN
#  define SQLITE_OS_WIN 0
# endif
#endif












/*
** Define the maximum size of a temporary filename
*/
#if SQLITE_OS_WIN
# include <windows.h>
# define SQLITE_TEMPNAME_SIZE (MAX_PATH+50)

# include <os2.h>
# include <uconv.h>
# define SQLITE_TEMPNAME_SIZE (CCHMAXPATHCOMP)
#else
# define SQLITE_TEMPNAME_SIZE 200
#endif

/*
** Determine if we are dealing with Windows NT.
*/
#if defined(_WIN32_WINNT)
# define SQLITE_OS_WINNT 1
#else
# define SQLITE_OS_WINNT 0
#endif

/*
** Determine if we are dealing with WindowsCE - which has a much
** reduced API.
*/
#if defined(_WIN32_WCE)
# define SQLITE_OS_WINCE 1
#else
# define SQLITE_OS_WINCE 0
#endif

/* If the SET_FULLSYNC macro is not defined above, then make it
** a no-op
*/
#ifndef SET_FULLSYNC
# define SET_FULLSYNC(x,y)
#endif

/*
** The default size of a disk sector
*/
#ifndef SQLITE_DEFAULT_SECTOR_SIZE
# define SQLITE_DEFAULT_SECTOR_SIZE 4096
#endif

/*
** Temporary files are named starting with this prefix followed by 16 random
** alphanumeric characters, and no file extension. They are stored in the
** OS's standard temporary file directory, and are deleted prior to exit.
** If sqlite is being embedded in another program, you may wish to change the

SQLITE_PRIVATE int sqlite3OsTruncate(sqlite3_file*, i64 size);
SQLITE_PRIVATE int sqlite3OsSync(sqlite3_file*, int);
SQLITE_PRIVATE int sqlite3OsFileSize(sqlite3_file*, i64 *pSize);
SQLITE_PRIVATE int sqlite3OsLock(sqlite3_file*, int);
SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file*, int);
SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file*,int,void*);
SQLITE_PRIVATE void sqlite3OsFileControlHint(sqlite3_file*,int,void*);
#define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id);
SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
SQLITE_PRIVATE int sqlite3OsShmMap(sqlite3_file *,int,int,int,void volatile **);
SQLITE_PRIVATE int sqlite3OsShmLock(sqlite3_file *id, int, int, int);
SQLITE_PRIVATE void sqlite3OsShmBarrier(sqlite3_file *id);
SQLITE_PRIVATE int sqlite3OsShmUnmap(sqlite3_file *id, int);


/* 
** Functions for accessing sqlite3_vfs methods 
*/
SQLITE_PRIVATE int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *);
SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *, const char *, int);
SQLITE_PRIVATE int sqlite3OsAccess(sqlite3_vfs *, const char *, int, int *pResOut);

** If both CollSeq.xCmp and CollSeq.xCmp16 are NULL, it means that the
** collating sequence is undefined.  Indices built on an undefined
** collating sequence may not be read or written.
*/
struct CollSeq {
  char *zName;          /* Name of the collating sequence, UTF-8 encoded */
  u8 enc;               /* Text encoding handled by xCmp() */

  void *pUser;          /* First argument to xCmp() */
  int (*xCmp)(void*,int, const void*, int, const void*);
  void (*xDel)(void*);  /* Destructor for pUser */
};









/*
** A sort order can be either ASC or DESC.
*/
#define SQLITE_SO_ASC       0  /* Sort in ascending order */
#define SQLITE_SO_DESC      1  /* Sort in ascending order */

/*

**
** This structure holds a record that has already been disassembled
** into its constituent fields.
*/
struct UnpackedRecord {
  KeyInfo *pKeyInfo;  /* Collation and sort-order information */
  u16 nField;         /* Number of entries in apMem[] */
  u8 flags;           /* Boolean settings.  UNPACKED_... below */
  i64 rowid;          /* Used by UNPACKED_PREFIX_SEARCH */
  Mem *aMem;          /* Values */
};

/*
** Allowed values of UnpackedRecord.flags
*/



#define UNPACKED_INCRKEY       0x01  /* Make this key an epsilon larger */
#define UNPACKED_PREFIX_MATCH  0x02  /* A prefix match is considered OK */
#define UNPACKED_PREFIX_SEARCH 0x04  /* Ignore final (rowid) field */

/*
** Each SQL index is represented in memory by an
** instance of the following structure.
**
** The columns of the table that are to be indexed are described
** by the aiColumn[] field of this structure.  For example, suppose

#define EP_VarSelect  0x0020  /* pSelect is correlated, not constant */
#define EP_DblQuoted  0x0040  /* token.z was originally in "..." */
#define EP_InfixFunc  0x0080  /* True for an infix function: LIKE, GLOB, etc */
#define EP_ExpCollate 0x0100  /* Collating sequence specified explicitly */
#define EP_FixedDest  0x0200  /* Result needed in a specific register */
#define EP_IntValue   0x0400  /* Integer value contained in u.iValue */
#define EP_xIsSelect  0x0800  /* x.pSelect is valid (otherwise x.pList is) */
#define EP_Hint       0x1000  /* Optimizer hint. Not required for correctness */
#define EP_Reduced    0x2000  /* Expr struct is EXPR_REDUCEDSIZE bytes only */
#define EP_TokenOnly  0x4000  /* Expr struct is EXPR_TOKENONLYSIZE bytes only */
#define EP_Static     0x8000  /* Held in memory not obtained from malloc() */

/*
** The following are the meanings of bits in the Expr.flags2 field.
*/
#define EP2_MallocedToken  0x0001  /* Need to sqlite3DbFree() Expr.zToken */
#define EP2_Irreducible    0x0002  /* Cannot EXPRDUP_REDUCE this Expr */

  int iECursor;          /* VDBE Cursor associated with this ExprList */
  struct ExprList_item {
    Expr *pExpr;           /* The list of expressions */
    char *zName;           /* Token associated with this expression */
    char *zSpan;           /* Original text of the expression */
    u8 sortOrder;          /* 1 for DESC or 0 for ASC */
    u8 done;               /* A flag to indicate when processing is finished */
    u16 iOrderByCol;       /* For ORDER BY, column number in result set */
    u16 iAlias;            /* Index into Parse.aAlias[] for zName */
  } *a;                  /* One entry for each expression */
};

/*
** An instance of this structure is used by the parser to record both
** the parse tree for an expression and the span of input text for an

  double nSelectRow;     /* Estimated number of result rows */
};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for
** "Select Flag".
*/
#define SF_Distinct        0x01  /* Output should be DISTINCT */
#define SF_Resolved        0x02  /* Identifiers have been resolved */
#define SF_Aggregate       0x04  /* Contains aggregate functions */
#define SF_UsesEphemeral   0x08  /* Uses the OpenEphemeral opcode */
#define SF_Expanded        0x10  /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo     0x20  /* FROM subqueries have Table metadata */
#define SF_UseSorter       0x40  /* Sort using a sorter */


/*
** The results of a select can be distributed in several ways.  The
** "SRT" prefix means "SELECT Result Type".
*/
#define SRT_Union        1  /* Store result as keys in an index */

*/
struct Parse {
  sqlite3 *db;         /* The main database structure */
  int rc;              /* Return code from execution */
  char *zErrMsg;       /* An error message */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */

  u8 checkSchema;      /* Causes schema cookie check after an error */
  u8 nested;           /* Number of nested calls to the parser/code generator */

  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 nTempInUse;       /* Number of aTempReg[] currently checked out */
  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nOnce;           /* Number of OP_Once instructions so far */
  int ckBase;          /* Base register of data during check constraints */
  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */
  u8 nColCache;        /* Number of entries in aColCache[] */
  u8 iColCache;        /* Next entry in aColCache[] to replace */
  struct yColCache {
    int iTable;           /* Table cursor number */
    int iColumn;          /* Table column number */
    u8 tempReg;           /* iReg is a temp register that needs to be freed */
    int iLevel;           /* Nesting level */
    int iReg;             /* Reg with value of this column. 0 means none. */
    int lru;              /* Least recently used entry has the smallest value */

  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */
  int nzVar;           /* Number of available slots in azVar[] */
  char **azVar;        /* Pointers to names of parameters */
  Vdbe *pReprepare;    /* VM being reprepared (sqlite3Reprepare()) */
  int nAlias;          /* Number of aliased result set columns */

  int *aAlias;         /* Register used to hold aliased result */
  u8 explain;          /* True if the EXPLAIN flag is found on the query */
  Token sNameToken;    /* Token with unqualified schema object name */
  Token sLastToken;    /* The last token parsed */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */

  int bFullMutex;                   /* True to enable full mutexing */
  int bOpenUri;                     /* True to interpret filenames as URIs */
  int mxStrlen;                     /* Maximum string length */
  int szLookaside;                  /* Default lookaside buffer size */
  int nLookaside;                   /* Default lookaside buffer count */
  sqlite3_mem_methods m;            /* Low-level memory allocation interface */
  sqlite3_mutex_methods mutex;      /* Low-level mutex interface */
  sqlite3_pcache_methods2 pcache2;  /* Low-level page-cache interface */
  void *pHeap;                      /* Heap storage space */
  int nHeap;                        /* Size of pHeap[] */
  int mnReq, mxReq;                 /* Min and max heap requests sizes */
  void *pScratch;                   /* Scratch memory */
  int szScratch;                    /* Size of each scratch buffer */
  int nScratch;                     /* Number of scratch buffers */
  void *pPage;                      /* Page cache memory */

SQLITE_PRIVATE char *sqlite3MAppendf(sqlite3*,char*,const char*,...);
#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
SQLITE_PRIVATE   void sqlite3DebugPrintf(const char*, ...);
#endif
#if defined(SQLITE_TEST)
SQLITE_PRIVATE   void *sqlite3TestTextToPtr(const char*);
#endif

/* Output formatting for SQLITE_TESTCTRL_EXPLAIN */
#if defined(SQLITE_ENABLE_TREE_EXPLAIN)
SQLITE_PRIVATE   void sqlite3ExplainBegin(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainPrintf(Vdbe*, const char*, ...);
SQLITE_PRIVATE   void sqlite3ExplainNL(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainPush(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainPop(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainFinish(Vdbe*);
SQLITE_PRIVATE   void sqlite3ExplainSelect(Vdbe*, Select*);
SQLITE_PRIVATE   void sqlite3ExplainExpr(Vdbe*, Expr*);
SQLITE_PRIVATE   void sqlite3ExplainExprList(Vdbe*, ExprList*);
SQLITE_PRIVATE   const char *sqlite3VdbeExplanation(Vdbe*);
#else
# define sqlite3ExplainBegin(X)
# define sqlite3ExplainSelect(A,B)
# define sqlite3ExplainExpr(A,B)
# define sqlite3ExplainExprList(A,B)
# define sqlite3ExplainFinish(X)
# define sqlite3VdbeExplanation(X) 0
#endif


SQLITE_PRIVATE void sqlite3SetString(char **, sqlite3*, const char*, ...);
SQLITE_PRIVATE void sqlite3ErrorMsg(Parse*, const char*, ...);
SQLITE_PRIVATE int sqlite3Dequote(char*);
SQLITE_PRIVATE int sqlite3KeywordCode(const unsigned char*, int);
SQLITE_PRIVATE int sqlite3RunParser(Parse*, const char*, char **);
SQLITE_PRIVATE void sqlite3FinishCoding(Parse*);
SQLITE_PRIVATE int sqlite3GetTempReg(Parse*);
SQLITE_PRIVATE void sqlite3ReleaseTempReg(Parse*,int);
SQLITE_PRIVATE int sqlite3GetTempRange(Parse*,int);
SQLITE_PRIVATE void sqlite3ReleaseTempRange(Parse*,int,int);
SQLITE_PRIVATE void sqlite3ClearTempRegCache(Parse*);
SQLITE_PRIVATE Expr *sqlite3ExprAlloc(sqlite3*,int,const Token*,int);
SQLITE_PRIVATE Expr *sqlite3Expr(sqlite3*,int,const char*);
SQLITE_PRIVATE void sqlite3ExprAttachSubtrees(sqlite3*,Expr*,Expr*,Expr*);
SQLITE_PRIVATE Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*, const Token*);
SQLITE_PRIVATE Expr *sqlite3ExprAnd(sqlite3*,Expr*, Expr*);
SQLITE_PRIVATE Expr *sqlite3ExprFunction(Parse*,ExprList*, Token*);
SQLITE_PRIVATE void sqlite3ExprAssignVarNumber(Parse*, Expr*);

SQLITE_PRIVATE void sqlite3AddCheckConstraint(Parse*, Expr*);
SQLITE_PRIVATE void sqlite3AddColumnType(Parse*,Token*);
SQLITE_PRIVATE void sqlite3AddDefaultValue(Parse*,ExprSpan*);
SQLITE_PRIVATE void sqlite3AddCollateType(Parse*, Token*);
SQLITE_PRIVATE void sqlite3EndTable(Parse*,Token*,Token*,Select*);
SQLITE_PRIVATE int sqlite3ParseUri(const char*,const char*,unsigned int*,
                    sqlite3_vfs**,char**,char **);
SQLITE_PRIVATE int sqlite3CodeOnce(Parse *);

SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32);
SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec*, u32);
SQLITE_PRIVATE int sqlite3BitvecSet(Bitvec*, u32);
SQLITE_PRIVATE void sqlite3BitvecClear(Bitvec*, u32, void*);
SQLITE_PRIVATE void sqlite3BitvecDestroy(Bitvec*);
SQLITE_PRIVATE u32 sqlite3BitvecSize(Bitvec*);

  FuncDestructor *pDestructor
);
SQLITE_PRIVATE int sqlite3ApiExit(sqlite3 *db, int);
SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *);

SQLITE_PRIVATE void sqlite3StrAccumInit(StrAccum*, char*, int, int);
SQLITE_PRIVATE void sqlite3StrAccumAppend(StrAccum*,const char*,int);
SQLITE_PRIVATE void sqlite3AppendSpace(StrAccum*,int);
SQLITE_PRIVATE char *sqlite3StrAccumFinish(StrAccum*);
SQLITE_PRIVATE void sqlite3StrAccumReset(StrAccum*);
SQLITE_PRIVATE void sqlite3SelectDestInit(SelectDest*,int,int);
SQLITE_PRIVATE Expr *sqlite3CreateColumnExpr(sqlite3 *, SrcList *, int, int);

SQLITE_PRIVATE void sqlite3BackupRestart(sqlite3_backup *);
SQLITE_PRIVATE void sqlite3BackupUpdate(sqlite3_backup *, Pgno, const u8 *);

   SQLITE_THREADSAFE==1,      /* bFullMutex */
   SQLITE_USE_URI,            /* bOpenUri */
   0x7ffffffe,                /* mxStrlen */
   128,                       /* szLookaside */
   500,                       /* nLookaside */
   {0,0,0,0,0,0,0,0},         /* m */
   {0,0,0,0,0,0,0,0,0},       /* mutex */
   {0,0,0,0,0,0,0,0,0,0,0,0,0},/* pcache2 */
   (void*)0,                  /* pHeap */
   0,                         /* nHeap */
   0, 0,                      /* mnHeap, mxHeap */
   (void*)0,                  /* pScratch */
   0,                         /* szScratch */
   0,                         /* nScratch */
   (void*)0,                  /* pPage */

** Boolean values
*/
typedef unsigned char Bool;

/* Opaque type used by code in vdbesort.c */
typedef struct VdbeSorter VdbeSorter;

/* Opaque type used by the explainer */
typedef struct Explain Explain;

/*
** A cursor is a pointer into a single BTree within a database file.
** The cursor can seek to a BTree entry with a particular key, or
** loop over all entries of the Btree.  You can also insert new BTree
** entries or retrieve the key or data from the entry that the cursor
** is currently pointing to.
** 

struct VdbeFrame {
  Vdbe *v;                /* VM this frame belongs to */
  int pc;                 /* Program Counter in parent (calling) frame */
  Op *aOp;                /* Program instructions for parent frame */
  int nOp;                /* Size of aOp array */
  Mem *aMem;              /* Array of memory cells for parent frame */
  int nMem;               /* Number of entries in aMem */
  u8 *aOnceFlag;          /* Array of OP_Once flags for parent frame */
  int nOnceFlag;          /* Number of entries in aOnceFlag */
  VdbeCursor **apCsr;     /* Array of Vdbe cursors for parent frame */
  u16 nCursor;            /* Number of entries in apCsr */
  void *token;            /* Copy of SubProgram.token */
  int nChildMem;          /* Number of memory cells for child frame */
  int nChildCsr;          /* Number of cursors for child frame */
  i64 lastRowid;          /* Last insert rowid (sqlite3.lastRowid) */
  int nChange;            /* Statement changes (Vdbe.nChanges)     */

  VdbeFunc *pVdbeFunc;  /* Auxilary data, if created. */
  Mem s;                /* The return value is stored here */
  Mem *pMem;            /* Memory cell used to store aggregate context */
  int isError;          /* Error code returned by the function. */
  CollSeq *pColl;       /* Collating sequence */
};

/*
** An Explain object accumulates indented output which is helpful
** in describing recursive data structures.
*/
struct Explain {
  Vdbe *pVdbe;       /* Attach the explanation to this Vdbe */
  StrAccum str;      /* The string being accumulated */
  int nIndent;       /* Number of elements in aIndent */
  u16 aIndent[100];  /* Levels of indentation */
  char zBase[100];   /* Initial space */
};

/*
** An instance of the virtual machine.  This structure contains the complete
** state of the virtual machine.
**
** The "sqlite3_stmt" structure pointer that is returned by sqlite3_prepare()
** is really a pointer to an instance of this structure.
**

  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
  char *zSql;             /* Text of the SQL statement that generated this */
  void *pFree;            /* Free this when deleting the vdbe */
#ifdef SQLITE_DEBUG
  FILE *trace;            /* Write an execution trace here, if not NULL */
#endif
#ifdef SQLITE_ENABLE_TREE_EXPLAIN
  Explain *pExplain;      /* The explainer */
  char *zExplain;         /* Explanation of data structures */
#endif
  VdbeFrame *pFrame;      /* Parent frame */
  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */
  int nFrame;             /* Number of frames in pFrame list */
  u32 expmask;            /* Binding to these vars invalidates VM */
  SubProgram *pProgram;   /* Linked list of all sub-programs used by VM */
  int nOnceFlag;          /* Size of array aOnceFlag[] */
  u8 *aOnceFlag;          /* Flags for OP_Once */
};

/*
** The following are allowed values for Vdbe.magic
*/
#define VDBE_MAGIC_INIT     0x26bceaa5    /* Building a VDBE program */
#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */

SQLITE_PRIVATE double sqlite3VdbeRealValue(Mem*);
SQLITE_PRIVATE void sqlite3VdbeIntegerAffinity(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemRealify(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemNumerify(Mem*);
SQLITE_PRIVATE int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
SQLITE_PRIVATE void sqlite3VdbeMemRelease(Mem *p);
SQLITE_PRIVATE void sqlite3VdbeMemReleaseExternal(Mem *p);
#define VdbeMemRelease(X)  \
  if((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame)) \
    sqlite3VdbeMemReleaseExternal(X);
SQLITE_PRIVATE int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
SQLITE_PRIVATE const char *sqlite3OpcodeName(int);
SQLITE_PRIVATE int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
SQLITE_PRIVATE int sqlite3VdbeCloseStatement(Vdbe *, int);
SQLITE_PRIVATE void sqlite3VdbeFrameDelete(VdbeFrame*);

SQLITE_PRIVATE   void sqlite3VdbeLeave(Vdbe*);
#else
# define sqlite3VdbeEnter(X)
# define sqlite3VdbeLeave(X)
#endif

#ifdef SQLITE_DEBUG
SQLITE_PRIVATE void sqlite3VdbeMemAboutToChange(Vdbe*,Mem*);
#endif

#ifndef SQLITE_OMIT_FOREIGN_KEY
SQLITE_PRIVATE int sqlite3VdbeCheckFk(Vdbe *, int);
#else
# define sqlite3VdbeCheckFk(p,i) 0
#endif

SQLITE_PRIVATE int sqlite3VdbeMemTranslate(Mem*, u8);
#ifdef SQLITE_DEBUG
SQLITE_PRIVATE   void sqlite3VdbePrintSql(Vdbe*);
SQLITE_PRIVATE   void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
#endif
SQLITE_PRIVATE int sqlite3VdbeMemHandleBom(Mem *pMem);

#ifndef SQLITE_OMIT_INCRBLOB
SQLITE_PRIVATE   int sqlite3VdbeMemExpandBlob(Mem *);
  #define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
#else
  #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
  #define ExpandBlob(P) SQLITE_OK
#endif

#endif /* !defined(_VDBEINT_H_) */

/************** End of vdbeInt.h *********************************************/
/************** Continuing where we left off in status.c *********************/

** from within OsOpen()), but some third-party implementations may.
** So we test the effects of a malloc() failing and the sqlite3OsXXX()
** function returning SQLITE_IOERR_NOMEM using the DO_OS_MALLOC_TEST macro.
**
** The following functions are instrumented for malloc() failure 
** testing:
**

**     sqlite3OsRead()
**     sqlite3OsWrite()
**     sqlite3OsSync()
**     sqlite3OsFileSize()
**     sqlite3OsLock()
**     sqlite3OsCheckReservedLock()
**     sqlite3OsFileControl()
**     sqlite3OsShmMap()
**     sqlite3OsOpen()
**     sqlite3OsDelete()
**     sqlite3OsAccess()
**     sqlite3OsFullPathname()
**
*/
#if defined(SQLITE_TEST)
SQLITE_API int sqlite3_memdebug_vfs_oom_test = 1;
  #define DO_OS_MALLOC_TEST(x)                                       \
  if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3IsMemJournal(x))) {  \
    void *pTstAlloc = sqlite3Malloc(10);                             \

SQLITE_PRIVATE int sqlite3OsUnlock(sqlite3_file *id, int lockType){
  return id->pMethods->xUnlock(id, lockType);
}
SQLITE_PRIVATE int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut){
  DO_OS_MALLOC_TEST(id);
  return id->pMethods->xCheckReservedLock(id, pResOut);
}

/*
** Use sqlite3OsFileControl() when we are doing something that might fail
** and we need to know about the failures.  Use sqlite3OsFileControlHint()
** when simply tossing information over the wall to the VFS and we do not
** really care if the VFS receives and understands the information since it
** is only a hint and can be safely ignored.  The sqlite3OsFileControlHint()
** routine has no return value since the return value would be meaningless.
*/
SQLITE_PRIVATE int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
  DO_OS_MALLOC_TEST(id);
  return id->pMethods->xFileControl(id, op, pArg);
}
SQLITE_PRIVATE void sqlite3OsFileControlHint(sqlite3_file *id, int op, void *pArg){
  (void)id->pMethods->xFileControl(id, op, pArg);
}

SQLITE_PRIVATE int sqlite3OsSectorSize(sqlite3_file *id){
  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
}
SQLITE_PRIVATE int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
  return id->pMethods->xDeviceCharacteristics(id);
}

SQLITE_PRIVATE int sqlite3OsShmMap(
  sqlite3_file *id,               /* Database file handle */
  int iPage,
  int pgsz,
  int bExtend,                    /* True to extend file if necessary */
  void volatile **pp              /* OUT: Pointer to mapping */
){
  DO_OS_MALLOC_TEST(id);
  return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);
}

/*
** The next group of routines are convenience wrappers around the
** VFS methods.
*/
SQLITE_PRIVATE int sqlite3OsOpen(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  sqlite3_file *pFile, 
  int flags, 
  int *pFlagsOut
){
  int rc;
  DO_OS_MALLOC_TEST(0);
  /* 0x87f7f is a mask of SQLITE_OPEN_ flags that are valid to be passed
  ** down into the VFS layer.  Some SQLITE_OPEN_ flags (for example,
  ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
  ** reaching the VFS. */
  rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x87f7f, pFlagsOut);
  assert( rc==SQLITE_OK || pFile->pMethods==0 );
  return rc;
}
SQLITE_PRIVATE int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  DO_OS_MALLOC_TEST(0);
  assert( dirSync==0 || dirSync==1 );
  return pVfs->xDelete(pVfs, zPath, dirSync);
}
SQLITE_PRIVATE int sqlite3OsAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut
){
  DO_OS_MALLOC_TEST(0);
  return pVfs->xAccess(pVfs, zPath, flags, pResOut);
}
SQLITE_PRIVATE int sqlite3OsFullPathname(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int nPathOut, 
  char *zPathOut
){
  DO_OS_MALLOC_TEST(0);
  zPathOut[0] = 0;
  return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
}
#ifndef SQLITE_OMIT_LOAD_EXTENSION
SQLITE_PRIVATE void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
  return pVfs->xDlOpen(pVfs, zPath);
}

/*
** This version of the memory allocator is the default.  It is
** used when no other memory allocator is specified using compile-time
** macros.
*/
#ifdef SQLITE_SYSTEM_MALLOC

/*
** Windows systems have malloc_usable_size() but it is called _msize()
*/
#if !defined(HAVE_MALLOC_USABLE_SIZE) && SQLITE_OS_WIN
# define HAVE_MALLOC_USABLE_SIZE 1
# define malloc_usable_size _msize
#endif

#if defined(__APPLE__)

/*
** Use the zone allocator available on apple products
*/
#include <sys/sysctl.h>
#include <malloc/malloc.h>
#include <libkern/OSAtomic.h>
static malloc_zone_t* _sqliteZone_;
#define SQLITE_MALLOC(x) malloc_zone_malloc(_sqliteZone_, (x))
#define SQLITE_FREE(x) malloc_zone_free(_sqliteZone_, (x));
#define SQLITE_REALLOC(x,y) malloc_zone_realloc(_sqliteZone_, (x), (y))
#define SQLITE_MALLOCSIZE(x) \
        (_sqliteZone_ ? _sqliteZone_->size(_sqliteZone_,x) : malloc_size(x))

#else /* if not __APPLE__ */

/*
** Use standard C library malloc and free on non-Apple systems.
*/
#define SQLITE_MALLOC(x)    malloc(x)
#define SQLITE_FREE(x)      free(x)
#define SQLITE_REALLOC(x,y) realloc((x),(y))

#ifdef HAVE_MALLOC_USABLE_SIZE
#include <malloc.h>
#define SQLITE_MALLOCSIZE(x) malloc_usable_size(x)
#else
#undef SQLITE_MALLOCSIZE
#endif

#endif /* __APPLE__ or not __APPLE__ */

/*
** Like malloc(), but remember the size of the allocation
** so that we can find it later using sqlite3MemSize().
**
** For this low-level routine, we are guaranteed that nByte>0 because
** cases of nByte<=0 will be intercepted and dealt with by higher level
** routines.
*/
static void *sqlite3MemMalloc(int nByte){
#ifdef SQLITE_MALLOCSIZE
  void *p = SQLITE_MALLOC( nByte );
  if( p==0 ){
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
  }
  return p;
#else
  sqlite3_int64 *p;
  assert( nByte>0 );
  nByte = ROUND8(nByte);
  p = SQLITE_MALLOC( nByte+8 );
  if( p ){
    p[0] = nByte;
    p++;
  }else{
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM, "failed to allocate %u bytes of memory", nByte);
  }
  return (void *)p;
#endif
}

/*
** Like free() but works for allocations obtained from sqlite3MemMalloc()
** or sqlite3MemRealloc().
**
** For this low-level routine, we already know that pPrior!=0 since
** cases where pPrior==0 will have been intecepted and dealt with
** by higher-level routines.
*/
static void sqlite3MemFree(void *pPrior){
#ifdef SQLITE_MALLOCSIZE
  SQLITE_FREE(pPrior);
#else
  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
  assert( pPrior!=0 );
  p--;
  SQLITE_FREE(p);
#endif
}

/*
** Report the allocated size of a prior return from xMalloc()
** or xRealloc().
*/
static int sqlite3MemSize(void *pPrior){
#ifdef SQLITE_MALLOCSIZE
  return pPrior ? (int)SQLITE_MALLOCSIZE(pPrior) : 0;
#else
  sqlite3_int64 *p;
  if( pPrior==0 ) return 0;
  p = (sqlite3_int64*)pPrior;
  p--;
  return (int)p[0];
#endif
}

/*
** Like realloc().  Resize an allocation previously obtained from
** sqlite3MemMalloc().
**
** For this low-level interface, we know that pPrior!=0.  Cases where
** pPrior==0 while have been intercepted by higher-level routine and
** redirected to xMalloc.  Similarly, we know that nByte>0 becauses
** cases where nByte<=0 will have been intercepted by higher-level
** routines and redirected to xFree.
*/
static void *sqlite3MemRealloc(void *pPrior, int nByte){
#ifdef SQLITE_MALLOCSIZE
  void *p = SQLITE_REALLOC(pPrior, nByte);
  if( p==0 ){
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM,
      "failed memory resize %u to %u bytes",
      SQLITE_MALLOCSIZE(pPrior), nByte);
  }
  return p;
#else
  sqlite3_int64 *p = (sqlite3_int64*)pPrior;
  assert( pPrior!=0 && nByte>0 );
  assert( nByte==ROUND8(nByte) ); /* EV: R-46199-30249 */
  p--;
  p = SQLITE_REALLOC(p, nByte+8 );
  if( p ){
    p[0] = nByte;
    p++;
  }else{
    testcase( sqlite3GlobalConfig.xLog!=0 );
    sqlite3_log(SQLITE_NOMEM,
      "failed memory resize %u to %u bytes",
      sqlite3MemSize(pPrior), nByte);
  }
  return (void*)p;
#endif
}

/*
** Round up a request size to the next valid allocation size.
*/
static int sqlite3MemRoundup(int n){
  return ROUND8(n);
}

/*
** Initialize this module.
*/
static int sqlite3MemInit(void *NotUsed){
#if defined(__APPLE__)
  int cpuCount;
  size_t len;
  if( _sqliteZone_ ){
    return SQLITE_OK;
  }
  len = sizeof(cpuCount);
  /* One usually wants to use hw.acctivecpu for MT decisions, but not here */
  sysctlbyname("hw.ncpu", &cpuCount, &len, NULL, 0);
  if( cpuCount>1 ){
    /* defer MT decisions to system malloc */
    _sqliteZone_ = malloc_default_zone();
  }else{
    /* only 1 core, use our own zone to contention over global locks, 
    ** e.g. we have our own dedicated locks */
    bool success;		
    malloc_zone_t* newzone = malloc_create_zone(4096, 0);
    malloc_set_zone_name(newzone, "Sqlite_Heap");
    do{
      success = OSAtomicCompareAndSwapPtrBarrier(NULL, newzone, 
                                 (void * volatile *)&_sqliteZone_);
    }while(!_sqliteZone_);
    if( !success ){	
      /* somebody registered a zone first */
      malloc_destroy_zone(newzone);
    }
  }
#endif
  UNUSED_PARAMETER(NotUsed);
  return SQLITE_OK;
}

/*
** Deinitialize this module.
*/

  return p==0 || sqlite3GlobalConfig.mutex.xMutexHeld(p);
}
SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex *p){
  return p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld(p);
}
#endif

#endif /* !defined(SQLITE_MUTEX_OMIT) */

/************** End of mutex.c ***********************************************/
/************** Begin file mutex_noop.c **************************************/
/*
** 2008 October 07
**
** The author disclaims copyright to this source code.  In place of

** If compiled with SQLITE_MUTEX_NOOP, then the no-op mutex implementation
** is used regardless of the run-time threadsafety setting.
*/
#ifdef SQLITE_MUTEX_NOOP
SQLITE_PRIVATE sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
  return sqlite3NoopMutex();
}
#endif /* defined(SQLITE_MUTEX_NOOP) */
#endif /* !defined(SQLITE_MUTEX_OMIT) */

/************** End of mutex_noop.c ******************************************/
/************** Begin file mutex_os2.c ***************************************/
/*
** 2007 August 28
**
** The author disclaims copyright to this source code.  In place of

    0
#endif
  };

  return &sMutex;
}

#endif /* SQLITE_MUTEX_PTHREADS */

/************** End of mutex_unix.c ******************************************/
/************** Begin file mutex_w32.c ***************************************/
/*
** 2007 August 14
**
** The author disclaims copyright to this source code.  In place of

** Set the soft heap-size limit for the library. Passing a zero or 
** negative value indicates no limit.
*/
SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){
  sqlite3_int64 priorLimit;
  sqlite3_int64 excess;
#ifndef SQLITE_OMIT_AUTOINIT
  int rc = sqlite3_initialize();
  if( rc ) return -1;
#endif
  sqlite3_mutex_enter(mem0.mutex);
  priorLimit = mem0.alarmThreshold;
  sqlite3_mutex_leave(mem0.mutex);
  if( n<0 ) return priorLimit;
  if( n>0 ){
    sqlite3MemoryAlarm(softHeapLimitEnforcer, 0, n);

  return (char)digit;
}
#endif /* SQLITE_OMIT_FLOATING_POINT */

/*
** Append N space characters to the given string buffer.
*/
SQLITE_PRIVATE void sqlite3AppendSpace(StrAccum *pAccum, int N){
  static const char zSpaces[] = "                             ";
  while( N>=(int)sizeof(zSpaces)-1 ){
    sqlite3StrAccumAppend(pAccum, zSpaces, sizeof(zSpaces)-1);
    N -= sizeof(zSpaces)-1;
  }
  if( N>0 ){
    sqlite3StrAccumAppend(pAccum, zSpaces, N);

    ** "length" characters long.  The field width is "width".  Do
    ** the output.
    */
    if( !flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        sqlite3AppendSpace(pAccum, nspace);
      }
    }
    if( length>0 ){
      sqlite3StrAccumAppend(pAccum, bufpt, length);
    }
    if( flag_leftjustify ){
      register int nspace;
      nspace = width-length;
      if( nspace>0 ){
        sqlite3AppendSpace(pAccum, nspace);
      }
    }
    sqlite3_free(zExtra);
  }/* End for loop over the format string */
} /* End of function */

/*

** do the suffix shortening regardless of URI parameter.
**
** Examples:
**
**     test.db-journal    =>   test.nal
**     test.db-wal        =>   test.wal
**     test.db-shm        =>   test.shm
**     test.db-mj7f3319fa =>   test.9fa
*/
SQLITE_PRIVATE void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
#if SQLITE_ENABLE_8_3_NAMES<2

  if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )

#endif
  {
    int i, sz;
    sz = sqlite3Strlen30(z);
    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
  }
}
#endif

/************** End of util.c ************************************************/
/************** Begin file hash.c ********************************************/
/*

#include <unistd.h>
/* #include <time.h> */
#include <sys/time.h>
#include <errno.h>
#ifndef SQLITE_OMIT_WAL
#include <sys/mman.h>
#endif


#if SQLITE_ENABLE_LOCKING_STYLE
# include <sys/ioctl.h>
# if OS_VXWORKS
#  include <semaphore.h>
#  include <limits.h>
# else

/*
** The unixFile structure is subclass of sqlite3_file specific to the unix
** VFS implementations.
*/
typedef struct unixFile unixFile;
struct unixFile {
  sqlite3_io_methods const *pMethod;  /* Always the first entry */
  sqlite3_vfs *pVfs;                  /* The VFS that created this unixFile */
  unixInodeInfo *pInode;              /* Info about locks on this inode */
  int h;                              /* The file descriptor */
  unsigned char eFileLock;            /* The type of lock held on this fd */
  unsigned char ctrlFlags;            /* Behavioral bits.  UNIXFILE_* flags */
  int lastErrno;                      /* The unix errno from last I/O error */
  void *lockingContext;               /* Locking style specific state */
  UnixUnusedFd *pUnused;              /* Pre-allocated UnixUnusedFd */
  const char *zPath;                  /* Name of the file */
  unixShm *pShm;                      /* Shared memory segment information */
  int szChunk;                        /* Configured by FCNTL_CHUNK_SIZE */
#if SQLITE_ENABLE_LOCKING_STYLE
  int openFlags;                      /* The flags specified at open() */
#endif
#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
  unsigned fsFlags;                   /* cached details from statfs() */
#endif
#if OS_VXWORKS

  struct vxworksFileId *pId;          /* Unique file ID */
#endif
#ifndef NDEBUG
  /* The next group of variables are used to track whether or not the
  ** transaction counter in bytes 24-27 of database files are updated
  ** whenever any part of the database changes.  An assertion fault will
  ** occur if a file is updated without also updating the transaction

#define UNIXFILE_RDONLY      0x02     /* Connection is read only */
#define UNIXFILE_PERSIST_WAL 0x04     /* Persistent WAL mode */
#ifndef SQLITE_DISABLE_DIRSYNC
# define UNIXFILE_DIRSYNC    0x08     /* Directory sync needed */
#else
# define UNIXFILE_DIRSYNC    0x00
#endif
#define UNIXFILE_PSOW        0x10     /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
#define UNIXFILE_DELETE      0x20     /* Delete on close */
#define UNIXFILE_URI         0x40     /* Filename might have query parameters */
#define UNIXFILE_NOLOCK      0x80     /* Do no file locking */

/*
** Include code that is common to all os_*.c files
*/
/************** Include os_common.h in the middle of os_unix.c ***************/
/************** Begin file os_common.h ***************************************/
/*

  { "unlink",       (sqlite3_syscall_ptr)unlink,           0 },
#define osUnlink    ((int(*)(const char*))aSyscall[16].pCurrent)

  { "openDirectory",    (sqlite3_syscall_ptr)openDirectory,      0 },
#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent)

  { "mkdir",        (sqlite3_syscall_ptr)mkdir,           0 },
#define osMkdir     ((int(*)(const char*,mode_t))aSyscall[18].pCurrent)

  { "rmdir",        (sqlite3_syscall_ptr)rmdir,           0 },
#define osRmdir     ((int(*)(const char*))aSyscall[19].pCurrent)

}; /* End of the overrideable system calls */

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "unix" VFSes.  Return SQLITE_OK opon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable
** system call named zName.

  unixFile *pFile = (unixFile*)id;
  if( pFile->h>=0 ){
    robust_close(pFile, pFile->h, __LINE__);
    pFile->h = -1;
  }
#if OS_VXWORKS
  if( pFile->pId ){
    if( pFile->ctrlFlags & UNIXFILE_DELETE ){
      osUnlink(pFile->pId->zCanonicalName);
    }
    vxworksReleaseFileId(pFile->pId);
    pFile->pId = 0;
  }
#endif
  OSTRACE(("CLOSE   %-3d\n", pFile->h));

/******************* End of the no-op lock implementation *********************
******************************************************************************/

/******************************************************************************
************************* Begin dot-file Locking ******************************
**
** The dotfile locking implementation uses the existance of separate lock
** files (really a directory) to control access to the database.  This works
** on just about every filesystem imaginable.  But there are serious downsides:
**
**    (1)  There is zero concurrency.  A single reader blocks all other
**         connections from reading or writing the database.
**
**    (2)  An application crash or power loss can leave stale lock files
**         sitting around that need to be cleared manually.
**
** Nevertheless, a dotlock is an appropriate locking mode for use if no
** other locking strategy is available.
**
** Dotfile locking works by creating a subdirectory in the same directory as
** the database and with the same name but with a ".lock" extension added.
** The existance of a lock directory implies an EXCLUSIVE lock.  All other
** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
*/

/*
** The file suffix added to the data base filename in order to create the
** lock directory.
*/
#define DOTLOCK_SUFFIX ".lock"

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, set *pResOut
** to a non-zero value otherwise *pResOut is set to zero.  The return value

** routine to lower a locking level.
**
** With dotfile locking, we really only support state (4): EXCLUSIVE.
** But we track the other locking levels internally.
*/
static int dotlockLock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;

  char *zLockFile = (char *)pFile->lockingContext;
  int rc = SQLITE_OK;


  /* If we have any lock, then the lock file already exists.  All we have
  ** to do is adjust our internal record of the lock level.
  */
  if( pFile->eFileLock > NO_LOCK ){
    pFile->eFileLock = eFileLock;
    /* Always update the timestamp on the old file */
#ifdef HAVE_UTIME
    utime(zLockFile, NULL);
#else
    utimes(zLockFile, NULL);
#endif
    return SQLITE_OK;
  }
  
  /* grab an exclusive lock */
  rc = osMkdir(zLockFile, 0777);
  if( rc<0 ){
    /* failed to open/create the lock directory */
    int tErrno = errno;
    if( EEXIST == tErrno ){
      rc = SQLITE_BUSY;
    } else {
      rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
      if( IS_LOCK_ERROR(rc) ){
        pFile->lastErrno = tErrno;
      }
    }
    return rc;
  } 

  
  /* got it, set the type and return ok */
  pFile->eFileLock = eFileLock;
  return rc;
}

/*
** Lower the locking level on file descriptor pFile to eFileLock.  eFileLock
** must be either NO_LOCK or SHARED_LOCK.
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
**
** When the locking level reaches NO_LOCK, delete the lock file.
*/
static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
  unixFile *pFile = (unixFile*)id;
  char *zLockFile = (char *)pFile->lockingContext;
  int rc;

  assert( pFile );
  OSTRACE(("UNLOCK  %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
	   pFile->eFileLock, getpid()));
  assert( eFileLock<=SHARED_LOCK );
  
  /* no-op if possible */

  if( eFileLock==SHARED_LOCK ){
    pFile->eFileLock = SHARED_LOCK;
    return SQLITE_OK;
  }
  
  /* To fully unlock the database, delete the lock file */
  assert( eFileLock==NO_LOCK );
  rc = osRmdir(zLockFile);
  if( rc<0 && errno==ENOTDIR ) rc = osUnlink(zLockFile);
  if( rc<0 ){
    int tErrno = errno;
    rc = 0;
    if( ENOENT != tErrno ){
      rc = SQLITE_IOERR_UNLOCK;
    }
    if( IS_LOCK_ERROR(rc) ){
      pFile->lastErrno = tErrno;
    }
    return rc; 

** See tickets #2741 and #2681.
**
** To avoid stomping the errno value on a failed read the lastErrno value
** is set before returning.
*/
static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
  int got;
  int prior = 0;
#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
  i64 newOffset;
#endif
  TIMER_START;
  do{
#if defined(USE_PREAD)
    got = osPread(id->h, pBuf, cnt, offset);
    SimulateIOError( got = -1 );
#elif defined(USE_PREAD64)
    got = osPread64(id->h, pBuf, cnt, offset);
    SimulateIOError( got = -1 );
#else
    newOffset = lseek(id->h, offset, SEEK_SET);
    SimulateIOError( newOffset-- );
    if( newOffset!=offset ){
      if( newOffset == -1 ){
        ((unixFile*)id)->lastErrno = errno;
      }else{
        ((unixFile*)id)->lastErrno = 0;			
      }
      return -1;
    }
    got = osRead(id->h, pBuf, cnt);
#endif

    if( got==cnt ) break;
    if( got<0 ){
      if( errno==EINTR ){ got = 1; continue; }
      prior = 0;
      ((unixFile*)id)->lastErrno = errno;
      break;
    }else if( got>0 ){
      cnt -= got;
      offset += got;
      prior += got;
      pBuf = (void*)(got + (char*)pBuf);
    }
  }while( got>0 );
  TIMER_END;
  OSTRACE(("READ    %-3d %5d %7lld %llu\n",
            id->h, got+prior, offset-prior, TIMER_ELAPSED));
  return got+prior;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/

      }
#endif
    }
  }

  return SQLITE_OK;
}

/*
** If *pArg is inititially negative then this is a query.  Set *pArg to
** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
**
** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
*/
static void unixModeBit(unixFile *pFile, unsigned char mask, int *pArg){
  if( *pArg<0 ){
    *pArg = (pFile->ctrlFlags & mask)!=0;
  }else if( (*pArg)==0 ){
    pFile->ctrlFlags &= ~mask;
  }else{
    pFile->ctrlFlags |= mask;
  }
}

/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
  unixFile *pFile = (unixFile*)id;
  switch( op ){

      int rc;
      SimulateIOErrorBenign(1);
      rc = fcntlSizeHint(pFile, *(i64 *)pArg);
      SimulateIOErrorBenign(0);
      return rc;
    }
    case SQLITE_FCNTL_PERSIST_WAL: {


      unixModeBit(pFile, UNIXFILE_PERSIST_WAL, (int*)pArg);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
      unixModeBit(pFile, UNIXFILE_PSOW, (int*)pArg);
      return SQLITE_OK;

    }
    case SQLITE_FCNTL_VFSNAME: {
      *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName);
      return SQLITE_OK;
    }
#ifndef NDEBUG
    /* The pager calls this method to signal that it has done
    ** a rollback and that the database is therefore unchanged and
    ** it hence it is OK for the transaction change counter to be
    ** unchanged.
    */
    case SQLITE_FCNTL_DB_UNCHANGED: {
      ((unixFile*)id)->dbUpdate = 0;
      return SQLITE_OK;
    }
#endif
#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
    case SQLITE_SET_LOCKPROXYFILE:
    case SQLITE_GET_LOCKPROXYFILE: {
      return proxyFileControl(id,op,pArg);
    }
#endif /* SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) */



  }
  return SQLITE_NOTFOUND;
}

/*
** Return the sector size in bytes of the underlying block device for
** the specified file. This is almost always 512 bytes, but may be
** larger for some devices.
**
** SQLite code assumes this function cannot fail. It also assumes that
** if two files are created in the same file-system directory (i.e.
** a database and its journal file) that the sector size will be the
** same for both.
*/
static int unixSectorSize(sqlite3_file *pFile){
  (void)pFile;
  return SQLITE_DEFAULT_SECTOR_SIZE;
}

/*
** Return the device characteristics for the file.
**
** This VFS is set up to return SQLITE_IOCAP_POWERSAFE_OVERWRITE by default.
** However, that choice is contraversial since technically the underlying
** file system does not always provide powersafe overwrites.  (In other
** words, after a power-loss event, parts of the file that were never
** written might end up being altered.)  However, non-PSOW behavior is very,
** very rare.  And asserting PSOW makes a large reduction in the amount
** of required I/O for journaling, since a lot of padding is eliminated.
**  Hence, while POWERSAFE_OVERWRITE is on by default, there is a file-control
** available to turn it off and URI query parameter available to turn it off.
*/
static int unixDeviceCharacteristics(sqlite3_file *id){
  unixFile *p = (unixFile*)id;
  if( p->ctrlFlags & UNIXFILE_PSOW ){
    return SQLITE_IOCAP_POWERSAFE_OVERWRITE;
  }else{
    return 0;
  }
}

#ifndef SQLITE_OMIT_WAL


/*
** Object used to represent an shared memory buffer.  

    */
    if( osFstat(pDbFd->h, &sStat) && pInode->bProcessLock==0 ){
      rc = SQLITE_IOERR_FSTAT;
      goto shm_open_err;
    }

#ifdef SQLITE_SHM_DIRECTORY
    nShmFilename = sizeof(SQLITE_SHM_DIRECTORY) + 31;
#else
    nShmFilename = 6 + (int)strlen(pDbFd->zPath);
#endif
    pShmNode = sqlite3_malloc( sizeof(*pShmNode) + nShmFilename );
    if( pShmNode==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename);
    zShmFilename = pShmNode->zFilename = (char*)&pShmNode[1];
#ifdef SQLITE_SHM_DIRECTORY
    sqlite3_snprintf(nShmFilename, zShmFilename, 
                     SQLITE_SHM_DIRECTORY "/sqlite-shm-%x-%x",
                     (u32)sStat.st_ino, (u32)sStat.st_dev);
#else
    sqlite3_snprintf(nShmFilename, zShmFilename, "%s-shm", pDbFd->zPath);
    sqlite3FileSuffix3(pDbFd->zPath, zShmFilename);
#endif
    pShmNode->h = -1;
    pDbFd->pInode->pShmNode = pShmNode;
    pShmNode->pInode = pDbFd->pInode;
    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pShmNode->mutex==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }

    if( pInode->bProcessLock==0 ){

      int openFlags = O_RDWR | O_CREAT;
      if( sqlite3_uri_boolean(pDbFd->zPath, "readonly_shm", 0) ){

        openFlags = O_RDONLY;
        pShmNode->isReadonly = 1;
      }
      pShmNode->h = robust_open(zShmFilename, openFlags, (sStat.st_mode&0777));
      if( pShmNode->h<0 ){
        if( pShmNode->h<0 ){
          rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShmFilename);

/*
** Initialize the contents of the unixFile structure pointed to by pId.
*/
static int fillInUnixFile(
  sqlite3_vfs *pVfs,      /* Pointer to vfs object */
  int h,                  /* Open file descriptor of file being opened */

  sqlite3_file *pId,      /* Write to the unixFile structure here */
  const char *zFilename,  /* Name of the file being opened */



  int ctrlFlags           /* Zero or more UNIXFILE_* values */
){
  const sqlite3_io_methods *pLockingStyle;
  unixFile *pNew = (unixFile *)pId;
  int rc = SQLITE_OK;

  assert( pNew->pInode==NULL );






  /* Usually the path zFilename should not be a relative pathname. The
  ** exception is when opening the proxy "conch" file in builds that
  ** include the special Apple locking styles.
  */
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
  assert( zFilename==0 || zFilename[0]=='/' 
    || pVfs->pAppData==(void*)&autolockIoFinder );
#else
  assert( zFilename==0 || zFilename[0]=='/' );
#endif

  /* No locking occurs in temporary files */
  assert( zFilename!=0 || (ctrlFlags & UNIXFILE_NOLOCK)!=0 );

  OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
  pNew->h = h;
  pNew->pVfs = pVfs;
  pNew->zPath = zFilename;

  pNew->ctrlFlags = (u8)ctrlFlags;

  if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0),

                           "psow", SQLITE_POWERSAFE_OVERWRITE) ){
    pNew->ctrlFlags |= UNIXFILE_PSOW;
  }
  if( memcmp(pVfs->zName,"unix-excl",10)==0 ){
    pNew->ctrlFlags |= UNIXFILE_EXCL;
  }

#if OS_VXWORKS
  pNew->pId = vxworksFindFileId(zFilename);
  if( pNew->pId==0 ){
    ctrlFlags |= UNIXFILE_NOLOCK;
    rc = SQLITE_NOMEM;
  }
#endif

  if( ctrlFlags & UNIXFILE_NOLOCK ){
    pLockingStyle = &nolockIoMethods;
  }else{
    pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew);
#if SQLITE_ENABLE_LOCKING_STYLE
    /* Cache zFilename in the locking context (AFP and dotlock override) for
    ** proxyLock activation is possible (remote proxy is based on db name)
    ** zFilename remains valid until file is closed, to support */

#if OS_VXWORKS
  if( rc!=SQLITE_OK ){
    if( h>=0 ) robust_close(pNew, h, __LINE__);
    h = -1;
    osUnlink(zFilename);
    isDelete = 0;
  }
  if( isDelete ) pNew->ctrlFlags |= UNIXFILE_DELETE;
#endif
  if( rc!=SQLITE_OK ){
    if( h>=0 ) robust_close(pNew, h, __LINE__);
  }else{
    pNew->pMethod = pLockingStyle;
    OpenCounter(+1);
  }

  zDir = unixTempFileDir();
  if( zDir==0 ) zDir = ".";

  /* Check that the output buffer is large enough for the temporary file 
  ** name. If it is not, return SQLITE_ERROR.
  */
  if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 18) >= (size_t)nBuf ){
    return SQLITE_ERROR;
  }

  do{
    sqlite3_snprintf(nBuf-18, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
    j = (int)strlen(zBuf);
    sqlite3_randomness(15, &zBuf[j]);
    for(i=0; i<15; i++, j++){
      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
    }
    zBuf[j] = 0;
    zBuf[j+1] = 0;
  }while( osAccess(zBuf,0)==0 );
  return SQLITE_OK;
}

#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
/*
** Routine to transform a unixFile into a proxy-locking unixFile.

    **   "<path to db>-walNN"
    **
    ** where NN is a decimal number. The NN naming schemes are 
    ** used by the test_multiplex.c module.
    */
    nDb = sqlite3Strlen30(zPath) - 1; 
#ifdef SQLITE_ENABLE_8_3_NAMES
    while( nDb>0 && sqlite3Isalnum(zPath[nDb]) ) nDb--;
    if( nDb==0 || zPath[nDb]!='-' ) return SQLITE_OK;
#else
    while( zPath[nDb]!='-' ){
      assert( nDb>0 );
      assert( zPath[nDb]!='\n' );
      nDb--;
    }

){
  unixFile *p = (unixFile *)pFile;
  int fd = -1;                   /* File descriptor returned by open() */
  int openFlags = 0;             /* Flags to pass to open() */
  int eType = flags&0xFFFFFF00;  /* Type of file to open */
  int noLock;                    /* True to omit locking primitives */
  int rc = SQLITE_OK;            /* Function Return Code */
  int ctrlFlags = 0;             /* UNIXFILE_* flags */

  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
  int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
  int isCreate     = (flags & SQLITE_OPEN_CREATE);
  int isReadonly   = (flags & SQLITE_OPEN_READONLY);
  int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
#if SQLITE_ENABLE_LOCKING_STYLE

     || eType==SQLITE_OPEN_MAIN_JOURNAL 
     || eType==SQLITE_OPEN_WAL
  ));

  /* If argument zPath is a NULL pointer, this function is required to open
  ** a temporary file. Use this buffer to store the file name in.
  */
  char zTmpname[MAX_PATHNAME+2];
  const char *zName = zPath;

  /* Check the following statements are true: 
  **
  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and 
  **   (b) if CREATE is set, then READWRITE must also be set, and
  **   (c) if EXCLUSIVE is set, then CREATE must also be set.

    }else{
      pUnused = sqlite3_malloc(sizeof(*pUnused));
      if( !pUnused ){
        return SQLITE_NOMEM;
      }
    }
    p->pUnused = pUnused;

    /* Database filenames are double-zero terminated if they are not
    ** URIs with parameters.  Hence, they can always be passed into
    ** sqlite3_uri_parameter(). */
    assert( (flags & SQLITE_OPEN_URI) || zName[strlen(zName)+1]==0 );

  }else if( !zName ){
    /* If zName is NULL, the upper layer is requesting a temp file. */
    assert(isDelete && !syncDir);
    rc = unixGetTempname(MAX_PATHNAME+2, zTmpname);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    zName = zTmpname;

    /* Generated temporary filenames are always double-zero terminated
    ** for use by sqlite3_uri_parameter(). */
    assert( zName[strlen(zName)+1]==0 );
  }

  /* Determine the value of the flags parameter passed to POSIX function
  ** open(). These must be calculated even if open() is not called, as
  ** they may be stored as part of the file handle and used by the 
  ** 'conch file' locking functions later on.  */
  if( isReadonly )  openFlags |= O_RDONLY;

    robust_close(p, fd, __LINE__);
    return SQLITE_IOERR_ACCESS;
  }
  if (0 == strncmp("msdos", fsInfo.f_fstypename, 5)) {
    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
  }
#endif

  /* Set up appropriate ctrlFlags */
  if( isDelete )                ctrlFlags |= UNIXFILE_DELETE;
  if( isReadonly )              ctrlFlags |= UNIXFILE_RDONLY;
  if( noLock )                  ctrlFlags |= UNIXFILE_NOLOCK;
  if( syncDir )                 ctrlFlags |= UNIXFILE_DIRSYNC;
  if( flags & SQLITE_OPEN_URI ) ctrlFlags |= UNIXFILE_URI;

#if SQLITE_ENABLE_LOCKING_STYLE
#if SQLITE_PREFER_PROXY_LOCKING
  isAutoProxy = 1;
#endif
  if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){
    char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
    int useProxy = 0;

        robust_close(p, fd, __LINE__);
        rc = SQLITE_IOERR_ACCESS;
        goto open_finished;
      }
      useProxy = !(fsInfo.f_flags&MNT_LOCAL);
    }
    if( useProxy ){
      rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);

      if( rc==SQLITE_OK ){
        rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
        if( rc!=SQLITE_OK ){
          /* Use unixClose to clean up the resources added in fillInUnixFile 
          ** and clear all the structure's references.  Specifically, 
          ** pFile->pMethods will be NULL so sqlite3OsClose will be a no-op 
          */
          unixClose(pFile);
          return rc;
        }
      }
      goto open_finished;
    }
  }
#endif
  
  rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);

open_finished:
  if( rc!=SQLITE_OK ){
    sqlite3_free(p->pUnused);
  }
  return rc;
}

  int rc = SQLITE_OK;
  UNUSED_PARAMETER(NotUsed);
  SimulateIOError(return SQLITE_IOERR_DELETE);
  if( osUnlink(zPath)==(-1) && errno!=ENOENT ){
    return unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
  }
#ifndef SQLITE_DISABLE_DIRSYNC
  if( (dirSync & 1)!=0 ){
    int fd;
    rc = osOpenDirectory(zPath, &fd);
    if( rc==SQLITE_OK ){
#if OS_VXWORKS
      if( fsync(fd)==-1 )
#else
      if( fsync(fd) )

  buf[0] = lockPath[0];
  for( i=1; i<len; i++ ){
    if( lockPath[i] == '/' && (i - start > 0) ){
      /* only mkdir if leaf dir != "." or "/" or ".." */
      if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/') 
         || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){
        buf[i]='\0';
        if( osMkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
          int err=errno;
          if( err!=EEXIST ) {
            OSTRACE(("CREATELOCKPATH  FAILED creating %s, "
                     "'%s' proxy lock path=%s pid=%d\n",
                     buf, strerror(err), lockPath, getpid()));
            return err;
          }

  memset(&dummyVfs, 0, sizeof(dummyVfs));
  dummyVfs.pAppData = (void*)&autolockIoFinder;
  dummyVfs.zName = "dummy";
  pUnused->fd = fd;
  pUnused->flags = openFlags;
  pNew->pUnused = pUnused;
  
  rc = fillInUnixFile(&dummyVfs, fd, (sqlite3_file*)pNew, path, 0);
  if( rc==SQLITE_OK ){
    *ppFile = pNew;
    return SQLITE_OK;
  }
end_create_proxy:    
  robust_close(pNew, fd, __LINE__);
  sqlite3_free(pNew);

    UNIXVFS("unix-proxy",    proxyIoFinder ),
#endif
  };
  unsigned int i;          /* Loop counter */

  /* Double-check that the aSyscall[] array has been constructed
  ** correctly.  See ticket [bb3a86e890c8e96ab] */
  assert( ArraySize(aSyscall)==20 );

  /* Register all VFSes defined in the aVfs[] array */
  for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
    sqlite3_vfs_register(&aVfs[i], i==0);
  }
  return SQLITE_OK; 
}

**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code that is specific to Windows.
*/
#if SQLITE_OS_WIN               /* This file is used for Windows only */






























#ifdef __CYGWIN__
# include <sys/cygwin.h>
#endif








/*
** Include code that is common to all os_*.c files
*/
/************** Include os_common.h in the middle of os_win.c ****************/
/************** Begin file os_common.h ***************************************/
/*
** 2004 May 22

#endif /* !defined(_OS_COMMON_H_) */

/************** End of os_common.h *******************************************/
/************** Continuing where we left off in os_win.c *********************/

/*
** Some Microsoft compilers lack this definition.
*/
#ifndef INVALID_FILE_ATTRIBUTES
# define INVALID_FILE_ATTRIBUTES ((DWORD)-1) 
#endif










/* Forward references */
typedef struct winShm winShm;           /* A connection to shared-memory */
typedef struct winShmNode winShmNode;   /* A region of shared-memory */

/*
** WinCE lacks native support for file locking so we have to fake it
** with some code of our own.

typedef struct winFile winFile;
struct winFile {
  const sqlite3_io_methods *pMethod; /*** Must be first ***/
  sqlite3_vfs *pVfs;      /* The VFS used to open this file */
  HANDLE h;               /* Handle for accessing the file */
  u8 locktype;            /* Type of lock currently held on this file */
  short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
  u8 ctrlFlags;           /* Flags.  See WINFILE_* below */
  DWORD lastErrno;        /* The Windows errno from the last I/O error */

  winShm *pShm;           /* Instance of shared memory on this file */
  const char *zPath;      /* Full pathname of this file */
  int szChunk;            /* Chunk size configured by FCNTL_CHUNK_SIZE */
#if SQLITE_OS_WINCE
  LPWSTR zDeleteOnClose;  /* Name of file to delete when closing */
  HANDLE hMutex;          /* Mutex used to control access to shared lock */  
  HANDLE hShared;         /* Shared memory segment used for locking */
  winceLock local;        /* Locks obtained by this instance of winFile */
  winceLock *shared;      /* Global shared lock memory for the file  */
#endif
};

/*
** Allowed values for winFile.ctrlFlags
*/
#define WINFILE_PERSIST_WAL     0x04   /* Persistent WAL mode */
#define WINFILE_PSOW            0x10   /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */

/*
 * If compiled with SQLITE_WIN32_MALLOC on Windows, we will use the
 * various Win32 API heap functions instead of our own.
 */
#ifdef SQLITE_WIN32_MALLOC
/*
 * The initial size of the Win32-specific heap.  This value may be zero.

static int winMemRoundup(int n);
static int winMemInit(void *pAppData);
static void winMemShutdown(void *pAppData);

SQLITE_PRIVATE const sqlite3_mem_methods *sqlite3MemGetWin32(void);
#endif /* SQLITE_WIN32_MALLOC */

/*








** The following variable is (normally) set once and never changes
** thereafter.  It records whether the operating system is Win9x
** or WinNT.
**
** 0:   Operating system unknown.
** 1:   Operating system is Win9x.
** 2:   Operating system is WinNT.
**
** In order to facilitate testing on a WinNT system, the test fixture
** can manually set this value to 1 to emulate Win98 behavior.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_os_type = 0;
#else
static int sqlite3_os_type = 0;
#endif

/*
** Many system calls are accessed through pointer-to-functions so that
** they may be overridden at runtime to facilitate fault injection during
** testing and sandboxing.  The following array holds the names and pointers
** to all overrideable system calls.
*/
#if !SQLITE_OS_WINCE
#  define SQLITE_WIN32_HAS_ANSI
#endif

#if SQLITE_OS_WINCE || SQLITE_OS_WINNT
#  define SQLITE_WIN32_HAS_WIDE
#endif

#ifndef SYSCALL
#  define SYSCALL sqlite3_syscall_ptr
#endif

#if SQLITE_OS_WINCE
/*
** These macros are necessary because Windows CE does not natively support the
** Win32 APIs LockFile, UnlockFile, and LockFileEx.
 */

#  define LockFile(a,b,c,d,e)       winceLockFile(&a, b, c, d, e)
#  define UnlockFile(a,b,c,d,e)     winceUnlockFile(&a, b, c, d, e)
#  define LockFileEx(a,b,c,d,e,f)   winceLockFileEx(&a, b, c, d, e, f)

/*
** These are the special syscall hacks for Windows CE.  The locking related
** defines here refer to the macros defined just above.
 */

#  define osAreFileApisANSI()       1
#  define osLockFile                LockFile
#  define osUnlockFile              UnlockFile
#  define osLockFileEx              LockFileEx
#endif

static struct win_syscall {
  const char *zName;            /* Name of the sytem call */
  sqlite3_syscall_ptr pCurrent; /* Current value of the system call */
  sqlite3_syscall_ptr pDefault; /* Default value */
} aSyscall[] = {
#if !SQLITE_OS_WINCE
  { "AreFileApisANSI",         (SYSCALL)AreFileApisANSI,         0 },

#define osAreFileApisANSI ((BOOL(WINAPI*)(VOID))aSyscall[0].pCurrent)
#else
  { "AreFileApisANSI",         (SYSCALL)0,                       0 },
#endif

#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
  { "CharLowerW",              (SYSCALL)CharLowerW,              0 },
#else
  { "CharLowerW",              (SYSCALL)0,                       0 },
#endif

#define osCharLowerW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[1].pCurrent)

#if SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
  { "CharUpperW",              (SYSCALL)CharUpperW,              0 },
#else
  { "CharUpperW",              (SYSCALL)0,                       0 },
#endif

#define osCharUpperW ((LPWSTR(WINAPI*)(LPWSTR))aSyscall[2].pCurrent)

  { "CloseHandle",             (SYSCALL)CloseHandle,             0 },

#define osCloseHandle ((BOOL(WINAPI*)(HANDLE))aSyscall[3].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "CreateFileA",             (SYSCALL)CreateFileA,             0 },
#else
  { "CreateFileA",             (SYSCALL)0,                       0 },
#endif

#define osCreateFileA ((HANDLE(WINAPI*)(LPCSTR,DWORD,DWORD, \
        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[4].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "CreateFileW",             (SYSCALL)CreateFileW,             0 },
#else
  { "CreateFileW",             (SYSCALL)0,                       0 },
#endif

#define osCreateFileW ((HANDLE(WINAPI*)(LPCWSTR,DWORD,DWORD, \
        LPSECURITY_ATTRIBUTES,DWORD,DWORD,HANDLE))aSyscall[5].pCurrent)

  { "CreateFileMapping",       (SYSCALL)CreateFileMapping,       0 },

#define osCreateFileMapping ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCTSTR))aSyscall[6].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "CreateFileMappingW",      (SYSCALL)CreateFileMappingW,      0 },
#else
  { "CreateFileMappingW",      (SYSCALL)0,                       0 },
#endif

#define osCreateFileMappingW ((HANDLE(WINAPI*)(HANDLE,LPSECURITY_ATTRIBUTES, \
        DWORD,DWORD,DWORD,LPCWSTR))aSyscall[7].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "CreateMutexW",            (SYSCALL)CreateMutexW,            0 },
#else
  { "CreateMutexW",            (SYSCALL)0,                       0 },
#endif

#define osCreateMutexW ((HANDLE(WINAPI*)(LPSECURITY_ATTRIBUTES,BOOL, \
        LPCWSTR))aSyscall[8].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "DeleteFileA",             (SYSCALL)DeleteFileA,             0 },
#else
  { "DeleteFileA",             (SYSCALL)0,                       0 },
#endif

#define osDeleteFileA ((BOOL(WINAPI*)(LPCSTR))aSyscall[9].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "DeleteFileW",             (SYSCALL)DeleteFileW,             0 },
#else
  { "DeleteFileW",             (SYSCALL)0,                       0 },
#endif

#define osDeleteFileW ((BOOL(WINAPI*)(LPCWSTR))aSyscall[10].pCurrent)

#if SQLITE_OS_WINCE
  { "FileTimeToLocalFileTime", (SYSCALL)FileTimeToLocalFileTime, 0 },
#else
  { "FileTimeToLocalFileTime", (SYSCALL)0,                       0 },
#endif

#define osFileTimeToLocalFileTime ((BOOL(WINAPI*)(CONST FILETIME*, \
        LPFILETIME))aSyscall[11].pCurrent)

#if SQLITE_OS_WINCE
  { "FileTimeToSystemTime",    (SYSCALL)FileTimeToSystemTime,    0 },
#else
  { "FileTimeToSystemTime",    (SYSCALL)0,                       0 },
#endif

#define osFileTimeToSystemTime ((BOOL(WINAPI*)(CONST FILETIME*, \
        LPSYSTEMTIME))aSyscall[12].pCurrent)

  { "FlushFileBuffers",        (SYSCALL)FlushFileBuffers,        0 },

#define osFlushFileBuffers ((BOOL(WINAPI*)(HANDLE))aSyscall[13].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "FormatMessageA",          (SYSCALL)FormatMessageA,          0 },
#else
  { "FormatMessageA",          (SYSCALL)0,                       0 },
#endif

#define osFormatMessageA ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPSTR, \
        DWORD,va_list*))aSyscall[14].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "FormatMessageW",          (SYSCALL)FormatMessageW,          0 },
#else
  { "FormatMessageW",          (SYSCALL)0,                       0 },
#endif

#define osFormatMessageW ((DWORD(WINAPI*)(DWORD,LPCVOID,DWORD,DWORD,LPWSTR, \
        DWORD,va_list*))aSyscall[15].pCurrent)

  { "FreeLibrary",             (SYSCALL)FreeLibrary,             0 },

#define osFreeLibrary ((BOOL(WINAPI*)(HMODULE))aSyscall[16].pCurrent)

  { "GetCurrentProcessId",     (SYSCALL)GetCurrentProcessId,     0 },

#define osGetCurrentProcessId ((DWORD(WINAPI*)(VOID))aSyscall[17].pCurrent)

#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
  { "GetDiskFreeSpaceA",       (SYSCALL)GetDiskFreeSpaceA,       0 },
#else
  { "GetDiskFreeSpaceA",       (SYSCALL)0,                       0 },
#endif

#define osGetDiskFreeSpaceA ((BOOL(WINAPI*)(LPCSTR,LPDWORD,LPDWORD,LPDWORD, \
        LPDWORD))aSyscall[18].pCurrent)

#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
  { "GetDiskFreeSpaceW",       (SYSCALL)GetDiskFreeSpaceW,       0 },
#else
  { "GetDiskFreeSpaceW",       (SYSCALL)0,                       0 },
#endif

#define osGetDiskFreeSpaceW ((BOOL(WINAPI*)(LPCWSTR,LPDWORD,LPDWORD,LPDWORD, \
        LPDWORD))aSyscall[19].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "GetFileAttributesA",      (SYSCALL)GetFileAttributesA,      0 },
#else
  { "GetFileAttributesA",      (SYSCALL)0,                       0 },
#endif

#define osGetFileAttributesA ((DWORD(WINAPI*)(LPCSTR))aSyscall[20].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "GetFileAttributesW",      (SYSCALL)GetFileAttributesW,      0 },
#else
  { "GetFileAttributesW",      (SYSCALL)0,                       0 },
#endif

#define osGetFileAttributesW ((DWORD(WINAPI*)(LPCWSTR))aSyscall[21].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "GetFileAttributesExW",    (SYSCALL)GetFileAttributesExW,    0 },
#else
  { "GetFileAttributesExW",    (SYSCALL)0,                       0 },
#endif

#define osGetFileAttributesExW ((BOOL(WINAPI*)(LPCWSTR,GET_FILEEX_INFO_LEVELS, \
        LPVOID))aSyscall[22].pCurrent)

  { "GetFileSize",             (SYSCALL)GetFileSize,             0 },

#define osGetFileSize ((DWORD(WINAPI*)(HANDLE,LPDWORD))aSyscall[23].pCurrent)

#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_ANSI)
  { "GetFullPathNameA",        (SYSCALL)GetFullPathNameA,        0 },
#else
  { "GetFullPathNameA",        (SYSCALL)0,                       0 },
#endif

#define osGetFullPathNameA ((DWORD(WINAPI*)(LPCSTR,DWORD,LPSTR, \
        LPSTR*))aSyscall[24].pCurrent)

#if !SQLITE_OS_WINCE && defined(SQLITE_WIN32_HAS_WIDE)
  { "GetFullPathNameW",        (SYSCALL)GetFullPathNameW,        0 },
#else
  { "GetFullPathNameW",        (SYSCALL)0,                       0 },
#endif

#define osGetFullPathNameW ((DWORD(WINAPI*)(LPCWSTR,DWORD,LPWSTR, \
        LPWSTR*))aSyscall[25].pCurrent)

  { "GetLastError",            (SYSCALL)GetLastError,            0 },

#define osGetLastError ((DWORD(WINAPI*)(VOID))aSyscall[26].pCurrent)

#if SQLITE_OS_WINCE
  /* The GetProcAddressA() routine is only available on Windows CE. */
  { "GetProcAddressA",         (SYSCALL)GetProcAddressA,         0 },
#else
  /* All other Windows platforms expect GetProcAddress() to take
  ** an ANSI string regardless of the _UNICODE setting */
  { "GetProcAddressA",         (SYSCALL)GetProcAddress,          0 },
#endif

#define osGetProcAddressA ((FARPROC(WINAPI*)(HMODULE, \
        LPCSTR))aSyscall[27].pCurrent)

  { "GetSystemInfo",           (SYSCALL)GetSystemInfo,           0 },

#define osGetSystemInfo ((VOID(WINAPI*)(LPSYSTEM_INFO))aSyscall[28].pCurrent)

  { "GetSystemTime",           (SYSCALL)GetSystemTime,           0 },

#define osGetSystemTime ((VOID(WINAPI*)(LPSYSTEMTIME))aSyscall[29].pCurrent)

#if !SQLITE_OS_WINCE
  { "GetSystemTimeAsFileTime", (SYSCALL)GetSystemTimeAsFileTime, 0 },
#else
  { "GetSystemTimeAsFileTime", (SYSCALL)0,                       0 },
#endif

#define osGetSystemTimeAsFileTime ((VOID(WINAPI*)( \
        LPFILETIME))aSyscall[30].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "GetTempPathA",            (SYSCALL)GetTempPathA,            0 },
#else
  { "GetTempPathA",            (SYSCALL)0,                       0 },
#endif

#define osGetTempPathA ((DWORD(WINAPI*)(DWORD,LPSTR))aSyscall[31].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "GetTempPathW",            (SYSCALL)GetTempPathW,            0 },
#else
  { "GetTempPathW",            (SYSCALL)0,                       0 },
#endif

#define osGetTempPathW ((DWORD(WINAPI*)(DWORD,LPWSTR))aSyscall[32].pCurrent)

  { "GetTickCount",            (SYSCALL)GetTickCount,            0 },

#define osGetTickCount ((DWORD(WINAPI*)(VOID))aSyscall[33].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "GetVersionExA",           (SYSCALL)GetVersionExA,           0 },
#else
  { "GetVersionExA",           (SYSCALL)0,                       0 },
#endif

#define osGetVersionExA ((BOOL(WINAPI*)( \
        LPOSVERSIONINFOA))aSyscall[34].pCurrent)

  { "HeapAlloc",               (SYSCALL)HeapAlloc,               0 },

#define osHeapAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD, \
        SIZE_T))aSyscall[35].pCurrent)

  { "HeapCreate",              (SYSCALL)HeapCreate,              0 },

#define osHeapCreate ((HANDLE(WINAPI*)(DWORD,SIZE_T, \
        SIZE_T))aSyscall[36].pCurrent)

  { "HeapDestroy",             (SYSCALL)HeapDestroy,             0 },

#define osHeapDestroy ((BOOL(WINAPI*)(HANDLE))aSyscall[37].pCurrent)

  { "HeapFree",                (SYSCALL)HeapFree,                0 },

#define osHeapFree ((BOOL(WINAPI*)(HANDLE,DWORD,LPVOID))aSyscall[38].pCurrent)

  { "HeapReAlloc",             (SYSCALL)HeapReAlloc,             0 },

#define osHeapReAlloc ((LPVOID(WINAPI*)(HANDLE,DWORD,LPVOID, \
        SIZE_T))aSyscall[39].pCurrent)

  { "HeapSize",                (SYSCALL)HeapSize,                0 },

#define osHeapSize ((SIZE_T(WINAPI*)(HANDLE,DWORD, \
        LPCVOID))aSyscall[40].pCurrent)

  { "HeapValidate",            (SYSCALL)HeapValidate,            0 },

#define osHeapValidate ((BOOL(WINAPI*)(HANDLE,DWORD, \
        LPCVOID))aSyscall[41].pCurrent)

#if defined(SQLITE_WIN32_HAS_ANSI)
  { "LoadLibraryA",            (SYSCALL)LoadLibraryA,            0 },
#else
  { "LoadLibraryA",            (SYSCALL)0,                       0 },
#endif

#define osLoadLibraryA ((HMODULE(WINAPI*)(LPCSTR))aSyscall[42].pCurrent)

#if defined(SQLITE_WIN32_HAS_WIDE)
  { "LoadLibraryW",            (SYSCALL)LoadLibraryW,            0 },
#else
  { "LoadLibraryW",            (SYSCALL)0,                       0 },
#endif

#define osLoadLibraryW ((HMODULE(WINAPI*)(LPCWSTR))aSyscall[43].pCurrent)

  { "LocalFree",               (SYSCALL)LocalFree,               0 },

#define osLocalFree ((HLOCAL(WINAPI*)(HLOCAL))aSyscall[44].pCurrent)

#if !SQLITE_OS_WINCE
  { "LockFile",                (SYSCALL)LockFile,                0 },

#define osLockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        DWORD))aSyscall[45].pCurrent)
#else
  { "LockFile",                (SYSCALL)0,                       0 },
#endif

#if !SQLITE_OS_WINCE
  { "LockFileEx",              (SYSCALL)LockFileEx,              0 },

#define osLockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[46].pCurrent)
#else
  { "LockFileEx",              (SYSCALL)0,                       0 },
#endif

  { "MapViewOfFile",           (SYSCALL)MapViewOfFile,           0 },

#define osMapViewOfFile ((LPVOID(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        SIZE_T))aSyscall[47].pCurrent)

  { "MultiByteToWideChar",     (SYSCALL)MultiByteToWideChar,     0 },

#define osMultiByteToWideChar ((int(WINAPI*)(UINT,DWORD,LPCSTR,int,LPWSTR, \
        int))aSyscall[48].pCurrent)

  { "QueryPerformanceCounter", (SYSCALL)QueryPerformanceCounter, 0 },

#define osQueryPerformanceCounter ((BOOL(WINAPI*)( \
        LARGE_INTEGER*))aSyscall[49].pCurrent)

  { "ReadFile",                (SYSCALL)ReadFile,                0 },

#define osReadFile ((BOOL(WINAPI*)(HANDLE,LPVOID,DWORD,LPDWORD, \
        LPOVERLAPPED))aSyscall[50].pCurrent)

  { "SetEndOfFile",            (SYSCALL)SetEndOfFile,            0 },

#define osSetEndOfFile ((BOOL(WINAPI*)(HANDLE))aSyscall[51].pCurrent)

  { "SetFilePointer",          (SYSCALL)SetFilePointer,          0 },

#define osSetFilePointer ((DWORD(WINAPI*)(HANDLE,LONG,PLONG, \
        DWORD))aSyscall[52].pCurrent)

  { "Sleep",                   (SYSCALL)Sleep,                   0 },

#define osSleep ((VOID(WINAPI*)(DWORD))aSyscall[53].pCurrent)

  { "SystemTimeToFileTime",    (SYSCALL)SystemTimeToFileTime,    0 },

#define osSystemTimeToFileTime ((BOOL(WINAPI*)(CONST SYSTEMTIME*, \
        LPFILETIME))aSyscall[54].pCurrent)

#if !SQLITE_OS_WINCE
  { "UnlockFile",              (SYSCALL)UnlockFile,              0 },

#define osUnlockFile ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        DWORD))aSyscall[55].pCurrent)
#else
  { "UnlockFile",              (SYSCALL)0,                       0 },
#endif

#if !SQLITE_OS_WINCE
  { "UnlockFileEx",            (SYSCALL)UnlockFileEx,            0 },

#define osUnlockFileEx ((BOOL(WINAPI*)(HANDLE,DWORD,DWORD,DWORD, \
        LPOVERLAPPED))aSyscall[56].pCurrent)
#else
  { "UnlockFileEx",            (SYSCALL)0,                       0 },
#endif

  { "UnmapViewOfFile",         (SYSCALL)UnmapViewOfFile,         0 },

#define osUnmapViewOfFile ((BOOL(WINAPI*)(LPCVOID))aSyscall[57].pCurrent)

  { "WideCharToMultiByte",     (SYSCALL)WideCharToMultiByte,     0 },

#define osWideCharToMultiByte ((int(WINAPI*)(UINT,DWORD,LPCWSTR,int,LPSTR,int, \
        LPCSTR,LPBOOL))aSyscall[58].pCurrent)

  { "WriteFile",               (SYSCALL)WriteFile,               0 },

#define osWriteFile ((BOOL(WINAPI*)(HANDLE,LPCVOID,DWORD,LPDWORD, \
        LPOVERLAPPED))aSyscall[59].pCurrent)

}; /* End of the overrideable system calls */

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "win32" VFSes.  Return SQLITE_OK opon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable
** system call named zName.
*/
static int winSetSystemCall(
  sqlite3_vfs *pNotUsed,        /* The VFS pointer.  Not used */
  const char *zName,            /* Name of system call to override */
  sqlite3_syscall_ptr pNewFunc  /* Pointer to new system call value */
){
  unsigned int i;
  int rc = SQLITE_NOTFOUND;

  UNUSED_PARAMETER(pNotUsed);
  if( zName==0 ){
    /* If no zName is given, restore all system calls to their default
    ** settings and return NULL
    */
    rc = SQLITE_OK;
    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
      if( aSyscall[i].pDefault ){
        aSyscall[i].pCurrent = aSyscall[i].pDefault;
      }
    }
  }else{
    /* If zName is specified, operate on only the one system call
    ** specified.
    */
    for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
      if( strcmp(zName, aSyscall[i].zName)==0 ){
        if( aSyscall[i].pDefault==0 ){
          aSyscall[i].pDefault = aSyscall[i].pCurrent;
        }
        rc = SQLITE_OK;
        if( pNewFunc==0 ) pNewFunc = aSyscall[i].pDefault;
        aSyscall[i].pCurrent = pNewFunc;
        break;
      }
    }
  }
  return rc;
}

/*
** Return the value of a system call.  Return NULL if zName is not a
** recognized system call name.  NULL is also returned if the system call
** is currently undefined.
*/
static sqlite3_syscall_ptr winGetSystemCall(
  sqlite3_vfs *pNotUsed,
  const char *zName
){
  unsigned int i;

  UNUSED_PARAMETER(pNotUsed);
  for(i=0; i<sizeof(aSyscall)/sizeof(aSyscall[0]); i++){
    if( strcmp(zName, aSyscall[i].zName)==0 ) return aSyscall[i].pCurrent;
  }
  return 0;
}

/*
** Return the name of the first system call after zName.  If zName==NULL
** then return the name of the first system call.  Return NULL if zName
** is the last system call or if zName is not the name of a valid
** system call.
*/
static const char *winNextSystemCall(sqlite3_vfs *p, const char *zName){
  int i = -1;

  UNUSED_PARAMETER(p);
  if( zName ){
    for(i=0; i<ArraySize(aSyscall)-1; i++){
      if( strcmp(zName, aSyscall[i].zName)==0 ) break;
    }
  }
  for(i++; i<ArraySize(aSyscall); i++){
    if( aSyscall[i].pCurrent!=0 ) return aSyscall[i].zName;
  }
  return 0;
}

/*
** Return true (non-zero) if we are running under WinNT, Win2K, WinXP,
** or WinCE.  Return false (zero) for Win95, Win98, or WinME.
**
** Here is an interesting observation:  Win95, Win98, and WinME lack
** the LockFileEx() API.  But we can still statically link against that
** API as long as we don't call it when running Win95/98/ME.  A call to
** this routine is used to determine if the host is Win95/98/ME or
** WinNT/2K/XP so that we will know whether or not we can safely call
** the LockFileEx() API.
*/
#if SQLITE_OS_WINCE
# define isNT()  (1)
#else
  static int isNT(void){
    if( sqlite3_os_type==0 ){
      OSVERSIONINFOA sInfo;
      sInfo.dwOSVersionInfoSize = sizeof(sInfo);
      osGetVersionExA(&sInfo);
      sqlite3_os_type = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1;
    }
    return sqlite3_os_type==2;
  }
#endif /* SQLITE_OS_WINCE */

#ifdef SQLITE_WIN32_MALLOC
/*
** Allocate nBytes of memory.
*/
static void *winMemMalloc(int nBytes){
  HANDLE hHeap;
  void *p;

  winMemAssertMagic();
  hHeap = winMemGetHeap();
  assert( hHeap!=0 );
  assert( hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
#endif
  assert( nBytes>=0 );
  p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
  if( !p ){
    sqlite3_log(SQLITE_NOMEM, "failed to HeapAlloc %u bytes (%d), heap=%p",
                nBytes, osGetLastError(), (void*)hHeap);
  }
  return p;
}

/*
** Free memory.
*/
static void winMemFree(void *pPrior){
  HANDLE hHeap;

  winMemAssertMagic();
  hHeap = winMemGetHeap();
  assert( hHeap!=0 );
  assert( hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
#endif
  if( !pPrior ) return; /* Passing NULL to HeapFree is undefined. */
  if( !osHeapFree(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) ){
    sqlite3_log(SQLITE_NOMEM, "failed to HeapFree block %p (%d), heap=%p",
                pPrior, osGetLastError(), (void*)hHeap);
  }
}

/*
** Change the size of an existing memory allocation
*/
static void *winMemRealloc(void *pPrior, int nBytes){
  HANDLE hHeap;
  void *p;

  winMemAssertMagic();
  hHeap = winMemGetHeap();
  assert( hHeap!=0 );
  assert( hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior) );
#endif
  assert( nBytes>=0 );
  if( !pPrior ){
    p = osHeapAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, (SIZE_T)nBytes);
  }else{
    p = osHeapReAlloc(hHeap, SQLITE_WIN32_HEAP_FLAGS, pPrior, (SIZE_T)nBytes);
  }
  if( !p ){
    sqlite3_log(SQLITE_NOMEM, "failed to %s %u bytes (%d), heap=%p",
                pPrior ? "HeapReAlloc" : "HeapAlloc", nBytes, osGetLastError(),
                (void*)hHeap);
  }
  return p;
}

/*
** Return the size of an outstanding allocation, in bytes.
*/
static int winMemSize(void *p){
  HANDLE hHeap;
  SIZE_T n;

  winMemAssertMagic();
  hHeap = winMemGetHeap();
  assert( hHeap!=0 );
  assert( hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert ( osHeapValidate(hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
#endif
  if( !p ) return 0;
  n = osHeapSize(hHeap, SQLITE_WIN32_HEAP_FLAGS, p);
  if( n==(SIZE_T)-1 ){
    sqlite3_log(SQLITE_NOMEM, "failed to HeapSize block %p (%d), heap=%p",
                p, osGetLastError(), (void*)hHeap);
    return 0;
  }
  return (int)n;
}

/*
** Round up a request size to the next valid allocation size.

*/
static int winMemInit(void *pAppData){
  winMemData *pWinMemData = (winMemData *)pAppData;

  if( !pWinMemData ) return SQLITE_ERROR;
  assert( pWinMemData->magic==WINMEM_MAGIC );
  if( !pWinMemData->hHeap ){
    pWinMemData->hHeap = osHeapCreate(SQLITE_WIN32_HEAP_FLAGS,
                                      SQLITE_WIN32_HEAP_INIT_SIZE,
                                      SQLITE_WIN32_HEAP_MAX_SIZE);
    if( !pWinMemData->hHeap ){
      sqlite3_log(SQLITE_NOMEM,
          "failed to HeapCreate (%d), flags=%u, initSize=%u, maxSize=%u",
          osGetLastError(), SQLITE_WIN32_HEAP_FLAGS,
          SQLITE_WIN32_HEAP_INIT_SIZE, SQLITE_WIN32_HEAP_MAX_SIZE);
      return SQLITE_NOMEM;
    }
    pWinMemData->bOwned = TRUE;
  }
  assert( pWinMemData->hHeap!=0 );
  assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
  assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
#endif
  return SQLITE_OK;
}

/*
** Deinitialize this module.
*/
static void winMemShutdown(void *pAppData){
  winMemData *pWinMemData = (winMemData *)pAppData;

  if( !pWinMemData ) return;
  if( pWinMemData->hHeap ){
    assert( pWinMemData->hHeap!=INVALID_HANDLE_VALUE );
#ifdef SQLITE_WIN32_MALLOC_VALIDATE
    assert( osHeapValidate(pWinMemData->hHeap, SQLITE_WIN32_HEAP_FLAGS, NULL) );
#endif
    if( pWinMemData->bOwned ){
      if( !osHeapDestroy(pWinMemData->hHeap) ){
        sqlite3_log(SQLITE_NOMEM, "failed to HeapDestroy (%d), heap=%p",
                    osGetLastError(), (void*)pWinMemData->hHeap);
      }
      pWinMemData->bOwned = FALSE;
    }
    pWinMemData->hHeap = NULL;
  }
}

SQLITE_PRIVATE void sqlite3MemSetDefault(void){
  sqlite3_config(SQLITE_CONFIG_MALLOC, sqlite3MemGetWin32());
}
#endif /* SQLITE_WIN32_MALLOC */

/*
** Convert a UTF-8 string to Microsoft Unicode (UTF-16?). 
**
** Space to hold the returned string is obtained from malloc.
*/
static LPWSTR utf8ToUnicode(const char *zFilename){
  int nChar;
  LPWSTR zWideFilename;

  nChar = osMultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
  if( nChar==0 ){
    return 0;
  }
  zWideFilename = sqlite3_malloc( nChar*sizeof(zWideFilename[0]) );
  if( zWideFilename==0 ){
    return 0;
  }
  nChar = osMultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename,
                                nChar);
  if( nChar==0 ){
    sqlite3_free(zWideFilename);
    zWideFilename = 0;
  }
  return zWideFilename;
}

/*
** Convert Microsoft Unicode to UTF-8.  Space to hold the returned string is
** obtained from sqlite3_malloc().
*/
static char *unicodeToUtf8(LPCWSTR zWideFilename){
  int nByte;
  char *zFilename;

  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, 0, 0, 0, 0);
  if( nByte == 0 ){
    return 0;
  }
  zFilename = sqlite3_malloc( nByte );
  if( zFilename==0 ){
    return 0;
  }
  nByte = osWideCharToMultiByte(CP_UTF8, 0, zWideFilename, -1, zFilename, nByte,
                                0, 0);
  if( nByte == 0 ){
    sqlite3_free(zFilename);
    zFilename = 0;
  }
  return zFilename;
}

/*
** Convert an ANSI string to Microsoft Unicode, based on the
** current codepage settings for file apis.
** 
** Space to hold the returned string is obtained
** from sqlite3_malloc.
*/
static LPWSTR mbcsToUnicode(const char *zFilename){
  int nByte;
  LPWSTR zMbcsFilename;
  int codepage = osAreFileApisANSI() ? CP_ACP : CP_OEMCP;

  nByte = osMultiByteToWideChar(codepage, 0, zFilename, -1, NULL,
                                0)*sizeof(WCHAR);
  if( nByte==0 ){
    return 0;
  }
  zMbcsFilename = sqlite3_malloc( nByte*sizeof(zMbcsFilename[0]) );
  if( zMbcsFilename==0 ){
    return 0;
  }
  nByte = osMultiByteToWideChar(codepage, 0, zFilename, -1, zMbcsFilename,
                                nByte);
  if( nByte==0 ){
    sqlite3_free(zMbcsFilename);
    zMbcsFilename = 0;
  }
  return zMbcsFilename;
}

/*
** Convert Microsoft Unicode to multi-byte character string, based on the
** user's ANSI codepage.
**
** Space to hold the returned string is obtained from
** sqlite3_malloc().
*/
static char *unicodeToMbcs(LPCWSTR zWideFilename){
  int nByte;
  char *zFilename;
  int codepage = osAreFileApisANSI() ? CP_ACP : CP_OEMCP;

  nByte = osWideCharToMultiByte(codepage, 0, zWideFilename, -1, 0, 0, 0, 0);
  if( nByte == 0 ){
    return 0;
  }
  zFilename = sqlite3_malloc( nByte );
  if( zFilename==0 ){
    return 0;
  }
  nByte = osWideCharToMultiByte(codepage, 0, zWideFilename, -1, zFilename,
                                nByte, 0, 0);
  if( nByte == 0 ){
    sqlite3_free(zFilename);
    zFilename = 0;
  }
  return zFilename;
}

/*
** Convert multibyte character string to UTF-8.  Space to hold the
** returned string is obtained from sqlite3_malloc().
*/
SQLITE_API char *sqlite3_win32_mbcs_to_utf8(const char *zFilename){
  char *zFilenameUtf8;
  LPWSTR zTmpWide;

  zTmpWide = mbcsToUnicode(zFilename);
  if( zTmpWide==0 ){
    return 0;
  }
  zFilenameUtf8 = unicodeToUtf8(zTmpWide);
  sqlite3_free(zTmpWide);
  return zFilenameUtf8;
}

/*
** Convert UTF-8 to multibyte character string.  Space to hold the 
** returned string is obtained from sqlite3_malloc().
*/
SQLITE_API char *sqlite3_win32_utf8_to_mbcs(const char *zFilename){
  char *zFilenameMbcs;
  LPWSTR zTmpWide;

  zTmpWide = utf8ToUnicode(zFilename);
  if( zTmpWide==0 ){
    return 0;
  }
  zFilenameMbcs = unicodeToMbcs(zTmpWide);
  sqlite3_free(zTmpWide);
  return zFilenameMbcs;
}


/*
** The return value of getLastErrorMsg
** is zero if the error message fits in the buffer, or non-zero
** otherwise (if the message was truncated).
*/
static int getLastErrorMsg(DWORD lastErrno, int nBuf, char *zBuf){
  /* FormatMessage returns 0 on failure.  Otherwise it
  ** returns the number of TCHARs written to the output
  ** buffer, excluding the terminating null char.
  */

  DWORD dwLen = 0;
  char *zOut = 0;

  if( isNT() ){
    LPWSTR zTempWide = NULL;
    dwLen = osFormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                             FORMAT_MESSAGE_FROM_SYSTEM |
                             FORMAT_MESSAGE_IGNORE_INSERTS,
                             NULL,
                             lastErrno,
                             0,
                             (LPWSTR) &zTempWide,
                             0,
                             0);
    if( dwLen > 0 ){
      /* allocate a buffer and convert to UTF8 */
      sqlite3BeginBenignMalloc();
      zOut = unicodeToUtf8(zTempWide);
      sqlite3EndBenignMalloc();
      /* free the system buffer allocated by FormatMessage */
      osLocalFree(zTempWide);
    }
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    char *zTemp = NULL;
    dwLen = osFormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                             FORMAT_MESSAGE_FROM_SYSTEM |
                             FORMAT_MESSAGE_IGNORE_INSERTS,
                             NULL,
                             lastErrno,
                             0,
                             (LPSTR) &zTemp,
                             0,
                             0);
    if( dwLen > 0 ){
      /* allocate a buffer and convert to UTF8 */
      sqlite3BeginBenignMalloc();
      zOut = sqlite3_win32_mbcs_to_utf8(zTemp);
      sqlite3EndBenignMalloc();
      /* free the system buffer allocated by FormatMessage */
      osLocalFree(zTemp);
    }
#endif
  }
  if( 0 == dwLen ){
    sqlite3_snprintf(nBuf, zBuf, "OsError 0x%x (%u)", lastErrno, lastErrno);
  }else{
    /* copy a maximum of nBuf chars to output buffer */
    sqlite3_snprintf(nBuf, zBuf, "%s", zOut);
    /* free the UTF8 buffer */
    sqlite3_free(zOut);
  }
  return 0;
}

/*
**
** This function - winLogErrorAtLine() - is only ever called via the macro
** winLogError().
**
** This routine is invoked after an error occurs in an OS function.
** It logs a message using sqlite3_log() containing the current value of
** error code and, if possible, the human-readable equivalent from 
** FormatMessage.
**
** The first argument passed to the macro should be the error code that
** will be returned to SQLite (e.g. SQLITE_IOERR_DELETE, SQLITE_CANTOPEN). 
** The two subsequent arguments should be the name of the OS function that
** failed and the the associated file-system path, if any.
*/
#define winLogError(a,b,c,d)   winLogErrorAtLine(a,b,c,d,__LINE__)
static int winLogErrorAtLine(
  int errcode,                    /* SQLite error code */
  DWORD lastErrno,                /* Win32 last error */
  const char *zFunc,              /* Name of OS function that failed */
  const char *zPath,              /* File path associated with error */
  int iLine                       /* Source line number where error occurred */
){
  char zMsg[500];                 /* Human readable error text */
  int i;                          /* Loop counter */


  zMsg[0] = 0;
  getLastErrorMsg(lastErrno, sizeof(zMsg), zMsg);
  assert( errcode!=SQLITE_OK );
  if( zPath==0 ) zPath = "";
  for(i=0; zMsg[i] && zMsg[i]!='\r' && zMsg[i]!='\n'; i++){}
  zMsg[i] = 0;
  sqlite3_log(errcode,
      "os_win.c:%d: (%d) %s(%s) - %s",
      iLine, lastErrno, zFunc, zPath, zMsg
  );

  return errcode;
}

/*
** The number of times that a ReadFile(), WriteFile(), and DeleteFile()

static int win32IoerrRetryDelay = SQLITE_WIN32_IOERR_RETRY_DELAY;

/*
** If a ReadFile() or WriteFile() error occurs, invoke this routine
** to see if it should be retried.  Return TRUE to retry.  Return FALSE
** to give up with an error.
*/
static int retryIoerr(int *pnRetry, DWORD *pError){
  DWORD e = osGetLastError();
  if( *pnRetry>=win32IoerrRetry ){
    if( pError ){
      *pError = e;
    }
    return 0;
  }

  if( e==ERROR_ACCESS_DENIED ||
      e==ERROR_LOCK_VIOLATION ||
      e==ERROR_SHARING_VIOLATION ){
    osSleep(win32IoerrRetryDelay*(1+*pnRetry));
    ++*pnRetry;
    return 1;
  }
  if( pError ){
    *pError = e;
  }
  return 0;
}

/*
** Log a I/O error retry episode.
*/
static void logIoerr(int nRetry){
  if( nRetry ){
    sqlite3_log(SQLITE_IOERR, 
      "delayed %dms for lock/sharing conflict",
      win32IoerrRetryDelay*nRetry*(nRetry+1)/2
    );
  }
}

#if SQLITE_OS_WINCE
/*************************************************************************
** This section contains code for WinCE only.
*/
/*
** Windows CE does not have a localtime() function.  So create a
** substitute.
*/
/* #include <time.h> */
struct tm *__cdecl localtime(const time_t *t)
{
  static struct tm y;
  FILETIME uTm, lTm;
  SYSTEMTIME pTm;
  sqlite3_int64 t64;
  t64 = *t;
  t64 = (t64 + 11644473600)*10000000;
  uTm.dwLowDateTime = (DWORD)(t64 & 0xFFFFFFFF);
  uTm.dwHighDateTime= (DWORD)(t64 >> 32);
  osFileTimeToLocalFileTime(&uTm,&lTm);
  osFileTimeToSystemTime(&lTm,&pTm);
  y.tm_year = pTm.wYear - 1900;
  y.tm_mon = pTm.wMonth - 1;
  y.tm_wday = pTm.wDayOfWeek;
  y.tm_mday = pTm.wDay;
  y.tm_hour = pTm.wHour;
  y.tm_min = pTm.wMinute;
  y.tm_sec = pTm.wSecond;
  return &y;
}








#define HANDLE_TO_WINFILE(a) (winFile*)&((char*)a)[-(int)offsetof(winFile,h)]

/*
** Acquire a lock on the handle h
*/
static void winceMutexAcquire(HANDLE h){
   DWORD dwErr;

#define winceMutexRelease(h) ReleaseMutex(h)

/*
** Create the mutex and shared memory used for locking in the file
** descriptor pFile
*/
static BOOL winceCreateLock(const char *zFilename, winFile *pFile){
  LPWSTR zTok;
  LPWSTR zName;
  BOOL bInit = TRUE;

  zName = utf8ToUnicode(zFilename);
  if( zName==0 ){
    /* out of memory */
    return FALSE;
  }

  /* Initialize the local lockdata */
  memset(&pFile->local, 0, sizeof(pFile->local));

  /* Replace the backslashes from the filename and lowercase it
  ** to derive a mutex name. */
  zTok = osCharLowerW(zName);
  for (;*zTok;zTok++){
    if (*zTok == '\\') *zTok = '_';
  }

  /* Create/open the named mutex */
  pFile->hMutex = osCreateMutexW(NULL, FALSE, zName);
  if (!pFile->hMutex){
    pFile->lastErrno = osGetLastError();
    winLogError(SQLITE_ERROR, pFile->lastErrno, "winceCreateLock1", zFilename);
    sqlite3_free(zName);
    return FALSE;
  }

  /* Acquire the mutex before continuing */
  winceMutexAcquire(pFile->hMutex);
  
  /* Since the names of named mutexes, semaphores, file mappings etc are 
  ** case-sensitive, take advantage of that by uppercasing the mutex name
  ** and using that as the shared filemapping name.
  */
  osCharUpperW(zName);
  pFile->hShared = osCreateFileMappingW(INVALID_HANDLE_VALUE, NULL,
                                        PAGE_READWRITE, 0, sizeof(winceLock),
                                        zName);  

  /* Set a flag that indicates we're the first to create the memory so it 
  ** must be zero-initialized */
  if (osGetLastError() == ERROR_ALREADY_EXISTS){
    bInit = FALSE;
  }

  sqlite3_free(zName);

  /* If we succeeded in making the shared memory handle, map it. */
  if (pFile->hShared){
    pFile->shared = (winceLock*)osMapViewOfFile(pFile->hShared, 
             FILE_MAP_READ|FILE_MAP_WRITE, 0, 0, sizeof(winceLock));
    /* If mapping failed, close the shared memory handle and erase it */
    if (!pFile->shared){
      pFile->lastErrno = osGetLastError();
      winLogError(SQLITE_ERROR, pFile->lastErrno,
               "winceCreateLock2", zFilename);
      osCloseHandle(pFile->hShared);
      pFile->hShared = NULL;
    }
  }

  /* If shared memory could not be created, then close the mutex and fail */
  if (pFile->hShared == NULL){
    winceMutexRelease(pFile->hMutex);
    osCloseHandle(pFile->hMutex);
    pFile->hMutex = NULL;
    return FALSE;
  }
  
  /* Initialize the shared memory if we're supposed to */
  if (bInit) {
    memset(pFile->shared, 0, sizeof(winceLock));
  }

  winceMutexRelease(pFile->hMutex);
  return TRUE;
}

/*

      pFile->shared->bPending = FALSE;
    }
    if (pFile->local.bExclusive){
      pFile->shared->bExclusive = FALSE;
    }

    /* De-reference and close our copy of the shared memory handle */
    osUnmapViewOfFile(pFile->shared);
    osCloseHandle(pFile->hShared);

    /* Done with the mutex */
    winceMutexRelease(pFile->hMutex);    
    osCloseHandle(pFile->hMutex);
    pFile->hMutex = NULL;
  }
}

/* 
** An implementation of the LockFile() API of Windows for CE
*/
static BOOL winceLockFile(
  HANDLE *phFile,
  DWORD dwFileOffsetLow,
  DWORD dwFileOffsetHigh,
  DWORD nNumberOfBytesToLockLow,
  DWORD nNumberOfBytesToLockHigh

  }

  winceMutexRelease(pFile->hMutex);
  return bReturn;
}

/*
** An implementation of the UnlockFile API of Windows for CE
*/
static BOOL winceUnlockFile(
  HANDLE *phFile,
  DWORD dwFileOffsetLow,
  DWORD dwFileOffsetHigh,
  DWORD nNumberOfBytesToUnlockLow,
  DWORD nNumberOfBytesToUnlockHigh

  }

  winceMutexRelease(pFile->hMutex);
  return bReturn;
}

/*
** An implementation of the LockFileEx() API of Windows for CE
*/
static BOOL winceLockFileEx(
  HANDLE *phFile,
  DWORD dwFlags,
  DWORD dwReserved,
  DWORD nNumberOfBytesToLockLow,
  DWORD nNumberOfBytesToLockHigh,

/*****************************************************************************
** The next group of routines implement the I/O methods specified
** by the sqlite3_io_methods object.
******************************************************************************/

/*
** Some Microsoft compilers lack this definition.
*/
#ifndef INVALID_SET_FILE_POINTER
# define INVALID_SET_FILE_POINTER ((DWORD)-1)
#endif

/*
** Move the current position of the file handle passed as the first 
** argument to offset iOffset within the file. If successful, return 0. 
** Otherwise, set pFile->lastErrno and return non-zero.
*/
static int seekWinFile(winFile *pFile, sqlite3_int64 iOffset){
  LONG upperBits;                 /* Most sig. 32 bits of new offset */
  LONG lowerBits;                 /* Least sig. 32 bits of new offset */
  DWORD dwRet;                    /* Value returned by SetFilePointer() */
  DWORD lastErrno;                /* Value returned by GetLastError() */

  upperBits = (LONG)((iOffset>>32) & 0x7fffffff);
  lowerBits = (LONG)(iOffset & 0xffffffff);

  /* API oddity: If successful, SetFilePointer() returns a dword 
  ** containing the lower 32-bits of the new file-offset. Or, if it fails,
  ** it returns INVALID_SET_FILE_POINTER. However according to MSDN, 
  ** INVALID_SET_FILE_POINTER may also be a valid new offset. So to determine 
  ** whether an error has actually occured, it is also necessary to call 
  ** GetLastError().
  */
  dwRet = osSetFilePointer(pFile->h, lowerBits, &upperBits, FILE_BEGIN);

  if( (dwRet==INVALID_SET_FILE_POINTER
      && ((lastErrno = osGetLastError())!=NO_ERROR)) ){
    pFile->lastErrno = lastErrno;
    winLogError(SQLITE_IOERR_SEEK, pFile->lastErrno,
             "seekWinFile", pFile->zPath);
    return 1;
  }

  return 0;
}

/*
** Close a file.
**
** It is reported that an attempt to close a handle might sometimes
** fail.  This is a very unreasonable result, but Windows is notorious
** for being unreasonable so I do not doubt that it might happen.  If
** the close fails, we pause for 100 milliseconds and try again.  As
** many as MX_CLOSE_ATTEMPT attempts to close the handle are made before
** giving up and returning an error.
*/
#define MX_CLOSE_ATTEMPT 3
static int winClose(sqlite3_file *id){
  int rc, cnt = 0;
  winFile *pFile = (winFile*)id;

  assert( id!=0 );
  assert( pFile->pShm==0 );
  OSTRACE(("CLOSE %d\n", pFile->h));
  do{
    rc = osCloseHandle(pFile->h);
    /* SimulateIOError( rc=0; cnt=MX_CLOSE_ATTEMPT; ); */
  }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (osSleep(100), 1) );
#if SQLITE_OS_WINCE
#define WINCE_DELETION_ATTEMPTS 3
  winceDestroyLock(pFile);
  if( pFile->zDeleteOnClose ){
    int cnt = 0;
    while(
           osDeleteFileW(pFile->zDeleteOnClose)==0
        && osGetFileAttributesW(pFile->zDeleteOnClose)!=0xffffffff 
        && cnt++ < WINCE_DELETION_ATTEMPTS
    ){
       osSleep(100);  /* Wait a little before trying again */
    }
    sqlite3_free(pFile->zDeleteOnClose);
  }
#endif
  OSTRACE(("CLOSE %d %s\n", pFile->h, rc ? "ok" : "failed"));
  OpenCounter(-1);
  return rc ? SQLITE_OK
            : winLogError(SQLITE_IOERR_CLOSE, osGetLastError(),
                          "winClose", pFile->zPath);
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/

  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_READ);
  OSTRACE(("READ %d lock=%d\n", pFile->h, pFile->locktype));

  if( seekWinFile(pFile, offset) ){
    return SQLITE_FULL;
  }
  while( !osReadFile(pFile->h, pBuf, amt, &nRead, 0) ){
    DWORD lastErrno;
    if( retryIoerr(&nRetry, &lastErrno) ) continue;
    pFile->lastErrno = lastErrno;
    return winLogError(SQLITE_IOERR_READ, pFile->lastErrno,
             "winRead", pFile->zPath);
  }
  logIoerr(nRetry);
  if( nRead<(DWORD)amt ){
    /* Unread parts of the buffer must be zero-filled */
    memset(&((char*)pBuf)[nRead], 0, amt-nRead);
    return SQLITE_IOERR_SHORT_READ;
  }

  OSTRACE(("WRITE %d lock=%d\n", pFile->h, pFile->locktype));

  rc = seekWinFile(pFile, offset);
  if( rc==0 ){
    u8 *aRem = (u8 *)pBuf;        /* Data yet to be written */
    int nRem = amt;               /* Number of bytes yet to be written */
    DWORD nWrite;                 /* Bytes written by each WriteFile() call */
    DWORD lastErrno = NO_ERROR;   /* Value returned by GetLastError() */

    while( nRem>0 ){
      if( !osWriteFile(pFile->h, aRem, nRem, &nWrite, 0) ){
        if( retryIoerr(&nRetry, &lastErrno) ) continue;
        break;
      }
      if( nWrite<=0 ) break;
      aRem += nWrite;
      nRem -= nWrite;
    }
    if( nRem>0 ){
      pFile->lastErrno = lastErrno;
      rc = 1;
    }
  }

  if( rc ){
    if(   ( pFile->lastErrno==ERROR_HANDLE_DISK_FULL )
       || ( pFile->lastErrno==ERROR_DISK_FULL )){
      return SQLITE_FULL;
    }
    return winLogError(SQLITE_IOERR_WRITE, pFile->lastErrno,
             "winWrite", pFile->zPath);
  }else{
    logIoerr(nRetry);
  }
  return SQLITE_OK;
}

/*

  */
  if( pFile->szChunk>0 ){
    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
  }

  /* SetEndOfFile() returns non-zero when successful, or zero when it fails. */
  if( seekWinFile(pFile, nByte) ){
    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
             "winTruncate1", pFile->zPath);
  }else if( 0==osSetEndOfFile(pFile->h) ){
    pFile->lastErrno = osGetLastError();
    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
             "winTruncate2", pFile->zPath);
  }

  OSTRACE(("TRUNCATE %d %lld %s\n", pFile->h, nByte, rc ? "failed" : "ok"));
  return rc;
}

#ifdef SQLITE_TEST

  /* If we compiled with the SQLITE_NO_SYNC flag, then syncing is a
  ** no-op
  */
#ifdef SQLITE_NO_SYNC
  return SQLITE_OK;
#else
  rc = osFlushFileBuffers(pFile->h);
  SimulateIOError( rc=FALSE );
  if( rc ){
    return SQLITE_OK;
  }else{
    pFile->lastErrno = osGetLastError();
    return winLogError(SQLITE_IOERR_FSYNC, pFile->lastErrno,
             "winSync", pFile->zPath);
  }
#endif
}

/*
** Determine the current size of a file in bytes
*/
static int winFileSize(sqlite3_file *id, sqlite3_int64 *pSize){
  DWORD upperBits;
  DWORD lowerBits;
  winFile *pFile = (winFile*)id;
  DWORD lastErrno;

  assert( id!=0 );
  SimulateIOError(return SQLITE_IOERR_FSTAT);
  lowerBits = osGetFileSize(pFile->h, &upperBits);
  if(   (lowerBits == INVALID_FILE_SIZE)
     && ((lastErrno = osGetLastError())!=NO_ERROR) )
  {
    pFile->lastErrno = lastErrno;
    return winLogError(SQLITE_IOERR_FSTAT, pFile->lastErrno,
             "winFileSize", pFile->zPath);
  }
  *pSize = (((sqlite3_int64)upperBits)<<32) + lowerBits;
  return SQLITE_OK;
}

/*
** LOCKFILE_FAIL_IMMEDIATELY is undefined on some Windows systems.
*/
#ifndef LOCKFILE_FAIL_IMMEDIATELY
# define LOCKFILE_FAIL_IMMEDIATELY 1
#endif

/*
** Acquire a reader lock.
** Different API routines are called depending on whether or not this
** is Win9x or WinNT.
*/
static int getReadLock(winFile *pFile){
  int res;
  if( isNT() ){
    OVERLAPPED ovlp;
    ovlp.Offset = SHARED_FIRST;
    ovlp.OffsetHigh = 0;
    ovlp.hEvent = 0;
    res = osLockFileEx(pFile->h, LOCKFILE_FAIL_IMMEDIATELY,
                       0, SHARED_SIZE, 0, &ovlp);
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
*/
#if SQLITE_OS_WINCE==0
  }else{
    int lk;
    sqlite3_randomness(sizeof(lk), &lk);
    pFile->sharedLockByte = (short)((lk & 0x7fffffff)%(SHARED_SIZE - 1));
    res = osLockFile(pFile->h, SHARED_FIRST+pFile->sharedLockByte, 0, 1, 0);
#endif
  }
  if( res == 0 ){
    pFile->lastErrno = osGetLastError();
    /* No need to log a failure to lock */
  }
  return res;
}

/*
** Undo a readlock
*/
static int unlockReadLock(winFile *pFile){
  int res;
  DWORD lastErrno;
  if( isNT() ){
    res = osUnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
*/
#if SQLITE_OS_WINCE==0
  }else{
    res = osUnlockFile(pFile->h, SHARED_FIRST + pFile->sharedLockByte, 0, 1, 0);
#endif
  }
  if( res==0 && ((lastErrno = osGetLastError())!=ERROR_NOT_LOCKED) ){
    pFile->lastErrno = lastErrno;
    winLogError(SQLITE_IOERR_UNLOCK, pFile->lastErrno,
             "unlockReadLock", pFile->zPath);
  }
  return res;
}

/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:

** This routine will only increase a lock.  The winUnlock() routine
** erases all locks at once and returns us immediately to locking level 0.
** It is not possible to lower the locking level one step at a time.  You
** must go straight to locking level 0.
*/
static int winLock(sqlite3_file *id, int locktype){
  int rc = SQLITE_OK;    /* Return code from subroutines */
  int res = 1;           /* Result of a Windows lock call */
  int newLocktype;       /* Set pFile->locktype to this value before exiting */
  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */
  winFile *pFile = (winFile*)id;
  DWORD lastErrno = NO_ERROR;

  assert( id!=0 );
  OSTRACE(("LOCK %d %d was %d(%d)\n",
           pFile->h, locktype, pFile->locktype, pFile->sharedLockByte));

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as

  */
  newLocktype = pFile->locktype;
  if(   (pFile->locktype==NO_LOCK)
     || (   (locktype==EXCLUSIVE_LOCK)
         && (pFile->locktype==RESERVED_LOCK))
  ){
    int cnt = 3;
    while( cnt-->0 && (res = osLockFile(pFile->h, PENDING_BYTE, 0, 1, 0))==0 ){
      /* Try 3 times to get the pending lock.  This is needed to work
      ** around problems caused by indexing and/or anti-virus software on
      ** Windows systems.
      ** If you are using this code as a model for alternative VFSes, do not
      ** copy this retry logic.  It is a hack intended for Windows only.
      */
      OSTRACE(("could not get a PENDING lock. cnt=%d\n", cnt));
      if( cnt ) osSleep(1);
    }
    gotPendingLock = res;
    if( !res ){
      lastErrno = osGetLastError();
    }
  }

  /* Acquire a shared lock
  */
  if( locktype==SHARED_LOCK && res ){
    assert( pFile->locktype==NO_LOCK );
    res = getReadLock(pFile);
    if( res ){
      newLocktype = SHARED_LOCK;
    }else{
      lastErrno = osGetLastError();
    }
  }

  /* Acquire a RESERVED lock
  */
  if( locktype==RESERVED_LOCK && res ){
    assert( pFile->locktype==SHARED_LOCK );
    res = osLockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    if( res ){
      newLocktype = RESERVED_LOCK;
    }else{
      lastErrno = osGetLastError();
    }
  }

  /* Acquire a PENDING lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    newLocktype = PENDING_LOCK;
    gotPendingLock = 0;
  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    assert( pFile->locktype>=SHARED_LOCK );
    res = unlockReadLock(pFile);
    OSTRACE(("unreadlock = %d\n", res));
    res = osLockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( res ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      lastErrno = osGetLastError();
      OSTRACE(("error-code = %d\n", lastErrno));
      getReadLock(pFile);
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && locktype==SHARED_LOCK ){
    osUnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res ){
    rc = SQLITE_OK;
  }else{
    OSTRACE(("LOCK FAILED %d trying for %d but got %d\n", pFile->h,
           locktype, newLocktype));
    pFile->lastErrno = lastErrno;
    rc = SQLITE_BUSY;
  }
  pFile->locktype = (u8)newLocktype;
  return rc;
}

/*

  SimulateIOError( return SQLITE_IOERR_CHECKRESERVEDLOCK; );

  assert( id!=0 );
  if( pFile->locktype>=RESERVED_LOCK ){
    rc = 1;
    OSTRACE(("TEST WR-LOCK %d %d (local)\n", pFile->h, rc));
  }else{
    rc = osLockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    if( rc ){
      osUnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
    }
    rc = !rc;
    OSTRACE(("TEST WR-LOCK %d %d (remote)\n", pFile->h, rc));
  }
  *pResOut = rc;
  return SQLITE_OK;
}

  int rc = SQLITE_OK;
  assert( pFile!=0 );
  assert( locktype<=SHARED_LOCK );
  OSTRACE(("UNLOCK %d to %d was %d(%d)\n", pFile->h, locktype,
          pFile->locktype, pFile->sharedLockByte));
  type = pFile->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    osUnlockFile(pFile->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    if( locktype==SHARED_LOCK && !getReadLock(pFile) ){
      /* This should never happen.  We should always be able to
      ** reacquire the read lock */
      rc = winLogError(SQLITE_IOERR_UNLOCK, osGetLastError(),
               "winUnlock", pFile->zPath);
    }
  }
  if( type>=RESERVED_LOCK ){
    osUnlockFile(pFile->h, RESERVED_BYTE, 0, 1, 0);
  }
  if( locktype==NO_LOCK && type>=SHARED_LOCK ){
    unlockReadLock(pFile);
  }
  if( type>=PENDING_LOCK ){
    osUnlockFile(pFile->h, PENDING_BYTE, 0, 1, 0);
  }
  pFile->locktype = (u8)locktype;
  return rc;
}

/*
** If *pArg is inititially negative then this is a query.  Set *pArg to
** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
**
** If *pArg is 0 or 1, then clear or set the mask bit of pFile->ctrlFlags.
*/
static void winModeBit(winFile *pFile, unsigned char mask, int *pArg){
  if( *pArg<0 ){
    *pArg = (pFile->ctrlFlags & mask)!=0;
  }else if( (*pArg)==0 ){
    pFile->ctrlFlags &= ~mask;
  }else{
    pFile->ctrlFlags |= mask;
  }
}

/*
** Control and query of the open file handle.
*/
static int winFileControl(sqlite3_file *id, int op, void *pArg){
  winFile *pFile = (winFile*)id;
  switch( op ){

          }
        }
        return rc;
      }
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_PERSIST_WAL: {


      winModeBit(pFile, WINFILE_PERSIST_WAL, (int*)pArg);


      return SQLITE_OK;
    }
    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
      winModeBit(pFile, WINFILE_PSOW, (int*)pArg);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_VFSNAME: {
      *(char**)pArg = sqlite3_mprintf("win32");
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_WIN32_AV_RETRY: {
      int *a = (int*)pArg;
      if( a[0]>0 ){
        win32IoerrRetry = a[0];
      }else{

**
** SQLite code assumes this function cannot fail. It also assumes that
** if two files are created in the same file-system directory (i.e.
** a database and its journal file) that the sector size will be the
** same for both.
*/
static int winSectorSize(sqlite3_file *id){
  (void)id;
  return SQLITE_DEFAULT_SECTOR_SIZE;
}

/*
** Return a vector of device characteristics.
*/
static int winDeviceCharacteristics(sqlite3_file *id){
  winFile *p = (winFile*)id;
  return SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN |
         ((p->ctrlFlags & WINFILE_PSOW)?SQLITE_IOCAP_POWERSAFE_OVERWRITE:0);
}

#ifndef SQLITE_OMIT_WAL

/* 
** Windows will only let you create file view mappings
** on allocation size granularity boundaries.

  if( lockType == _SHM_WRLCK ) dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;

  memset(&ovlp, 0, sizeof(OVERLAPPED));
  ovlp.Offset = ofst;

  /* Release/Acquire the system-level lock */
  if( lockType==_SHM_UNLCK ){
    rc = osUnlockFileEx(pFile->hFile.h, 0, nByte, 0, &ovlp);
  }else{
    rc = osLockFileEx(pFile->hFile.h, dwFlags, 0, nByte, 0, &ovlp);
  }
  
  if( rc!= 0 ){
    rc = SQLITE_OK;
  }else{
    pFile->lastErrno =  osGetLastError();
    rc = SQLITE_BUSY;
  }

  OSTRACE(("SHM-LOCK %d %s %s 0x%08lx\n", 
           pFile->hFile.h,
           rc==SQLITE_OK ? "ok" : "failed",
           lockType==_SHM_UNLCK ? "UnlockFileEx" : "LockFileEx",

  assert( winShmMutexHeld() );
  pp = &winShmNodeList;
  while( (p = *pp)!=0 ){
    if( p->nRef==0 ){
      int i;
      if( p->mutex ) sqlite3_mutex_free(p->mutex);
      for(i=0; i<p->nRegion; i++){
        bRc = osUnmapViewOfFile(p->aRegion[i].pMap);
        OSTRACE(("SHM-PURGE pid-%d unmap region=%d %s\n",
                 (int)osGetCurrentProcessId(), i,
                 bRc ? "ok" : "failed"));
        bRc = osCloseHandle(p->aRegion[i].hMap);
        OSTRACE(("SHM-PURGE pid-%d close region=%d %s\n",
                 (int)osGetCurrentProcessId(), i,
                 bRc ? "ok" : "failed"));
      }
      if( p->hFile.h != INVALID_HANDLE_VALUE ){
        SimulateIOErrorBenign(1);
        winClose((sqlite3_file *)&p->hFile);
        SimulateIOErrorBenign(0);
      }
      if( deleteFlag ){
        SimulateIOErrorBenign(1);
        sqlite3BeginBenignMalloc();
        winDelete(pVfs, p->zFilename, 0);
        sqlite3EndBenignMalloc();
        SimulateIOErrorBenign(0);
      }
      *pp = p->pNext;
      sqlite3_free(p->aRegion);
      sqlite3_free(p);
    }else{
      pp = &p->pNext;

  assert( pDbFd->pShm==0 );    /* Not previously opened */

  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new winShmNode and filename.
  */
  p = sqlite3_malloc( sizeof(*p) );
  if( p==0 ) return SQLITE_IOERR_NOMEM;
  memset(p, 0, sizeof(*p));
  nName = sqlite3Strlen30(pDbFd->zPath);
  pNew = sqlite3_malloc( sizeof(*pShmNode) + nName + 17 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_IOERR_NOMEM;
  }
  memset(pNew, 0, sizeof(*pNew) + nName + 17);
  pNew->zFilename = (char*)&pNew[1];
  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename); 

  /* Look to see if there is an existing winShmNode that can be used.
  ** If no matching winShmNode currently exists, create a new one.
  */

    pNew = 0;
    ((winFile*)(&pShmNode->hFile))->h = INVALID_HANDLE_VALUE;
    pShmNode->pNext = winShmNodeList;
    winShmNodeList = pShmNode;

    pShmNode->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
    if( pShmNode->mutex==0 ){
      rc = SQLITE_IOERR_NOMEM;
      goto shm_open_err;
    }

    rc = winOpen(pDbFd->pVfs,
                 pShmNode->zFilename,             /* Name of the file (UTF-8) */
                 (sqlite3_file*)&pShmNode->hFile,  /* File handle here */
                 SQLITE_OPEN_WAL | SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, /* Mode flags */
                 0);
    if( SQLITE_OK!=rc ){

      goto shm_open_err;
    }

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, 0);
      if( rc!=SQLITE_OK ){
        rc = winLogError(SQLITE_IOERR_SHMOPEN, osGetLastError(),
                 "winOpenShm", pDbFd->zPath);
      }
    }
    if( rc==SQLITE_OK ){
      winShmSystemLock(pShmNode, _SHM_UNLCK, WIN_SHM_DMS, 1);
      rc = winShmSystemLock(pShmNode, _SHM_RDLCK, WIN_SHM_DMS, 1);
    }
    if( rc ) goto shm_open_err;

        assert( (p->sharedMask & mask)==0 );
        p->exclMask |= mask;
      }
    }
  }
  sqlite3_mutex_leave(pShmNode->mutex);
  OSTRACE(("SHM-LOCK shmid-%d, pid-%d got %03x,%03x %s\n",
           p->id, (int)osGetCurrentProcessId(), p->sharedMask, p->exclMask,
           rc ? "failed" : "ok"));
  return rc;
}

/*
** Implement a memory barrier or memory fence on shared memory.  
**

    /* The requested region is not mapped into this processes address space.
    ** Check to see if it has been allocated (i.e. if the wal-index file is
    ** large enough to contain the requested region).
    */
    rc = winFileSize((sqlite3_file *)&pShmNode->hFile, &sz);
    if( rc!=SQLITE_OK ){
      rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
               "winShmMap1", pDbFd->zPath);
      goto shmpage_out;
    }

    if( sz<nByte ){
      /* The requested memory region does not exist. If isWrite is set to
      ** zero, exit early. *pp will be set to NULL and SQLITE_OK returned.
      **
      ** Alternatively, if isWrite is non-zero, use ftruncate() to allocate
      ** the requested memory region.
      */
      if( !isWrite ) goto shmpage_out;
      rc = winTruncate((sqlite3_file *)&pShmNode->hFile, nByte);
      if( rc!=SQLITE_OK ){
        rc = winLogError(SQLITE_IOERR_SHMSIZE, osGetLastError(),
                 "winShmMap2", pDbFd->zPath);
        goto shmpage_out;
      }
    }

    /* Map the requested memory region into this processes address space. */
    apNew = (struct ShmRegion *)sqlite3_realloc(
        pShmNode->aRegion, (iRegion+1)*sizeof(apNew[0])
    );
    if( !apNew ){
      rc = SQLITE_IOERR_NOMEM;
      goto shmpage_out;
    }
    pShmNode->aRegion = apNew;

    while( pShmNode->nRegion<=iRegion ){
      HANDLE hMap;                /* file-mapping handle */
      void *pMap = 0;             /* Mapped memory region */
     
      hMap = osCreateFileMapping(pShmNode->hFile.h, 
          NULL, PAGE_READWRITE, 0, nByte, NULL
      );
      OSTRACE(("SHM-MAP pid-%d create region=%d nbyte=%d %s\n",
               (int)osGetCurrentProcessId(), pShmNode->nRegion, nByte,
               hMap ? "ok" : "failed"));
      if( hMap ){
        int iOffset = pShmNode->nRegion*szRegion;
        int iOffsetShift = iOffset % winSysInfo.dwAllocationGranularity;
        pMap = osMapViewOfFile(hMap, FILE_MAP_WRITE | FILE_MAP_READ,
            0, iOffset - iOffsetShift, szRegion + iOffsetShift
        );
        OSTRACE(("SHM-MAP pid-%d map region=%d offset=%d size=%d %s\n",
                 (int)osGetCurrentProcessId(), pShmNode->nRegion, iOffset,
                 szRegion, pMap ? "ok" : "failed"));
      }
      if( !pMap ){
        pShmNode->lastErrno = osGetLastError();
        rc = winLogError(SQLITE_IOERR_SHMMAP, pShmNode->lastErrno,
                 "winShmMap3", pDbFd->zPath);
        if( hMap ) osCloseHandle(hMap);
        goto shmpage_out;
      }

      pShmNode->aRegion[pShmNode->nRegion].pMap = pMap;
      pShmNode->aRegion[pShmNode->nRegion].hMap = hMap;
      pShmNode->nRegion++;
    }

*/
static int getTempname(int nBuf, char *zBuf){
  static char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  size_t i, j;
  char zTempPath[MAX_PATH+2];

  /* It's odd to simulate an io-error here, but really this is just
  ** using the io-error infrastructure to test that SQLite handles this
  ** function failing. 
  */
  SimulateIOError( return SQLITE_IOERR );

  if( sqlite3_temp_directory ){
    sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", sqlite3_temp_directory);
  }else if( isNT() ){
    char *zMulti;
    WCHAR zWidePath[MAX_PATH];
    osGetTempPathW(MAX_PATH-30, zWidePath);
    zMulti = unicodeToUtf8(zWidePath);
    if( zMulti ){
      sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", zMulti);
      sqlite3_free(zMulti);
    }else{
      return SQLITE_IOERR_NOMEM;
    }
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    char *zUtf8;
    char zMbcsPath[MAX_PATH];
    osGetTempPathA(MAX_PATH-30, zMbcsPath);
    zUtf8 = sqlite3_win32_mbcs_to_utf8(zMbcsPath);
    if( zUtf8 ){
      sqlite3_snprintf(MAX_PATH-30, zTempPath, "%s", zUtf8);
      sqlite3_free(zUtf8);
    }else{
      return SQLITE_IOERR_NOMEM;
    }
#endif
  }

  /* Check that the output buffer is large enough for the temporary file 
  ** name. If it is not, return SQLITE_ERROR.
  */
  if( (sqlite3Strlen30(zTempPath) + sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX) + 18) >= nBuf ){
    return SQLITE_ERROR;
  }

  for(i=sqlite3Strlen30(zTempPath); i>0 && zTempPath[i-1]=='\\'; i--){}
  zTempPath[i] = 0;

  sqlite3_snprintf(nBuf-18, zBuf,
                   "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath);
  j = sqlite3Strlen30(zBuf);
  sqlite3_randomness(15, &zBuf[j]);
  for(i=0; i<15; i++, j++){
    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
  }
  zBuf[j] = 0;
  zBuf[j+1] = 0;

  OSTRACE(("TEMP FILENAME: %s\n", zBuf));
  return SQLITE_OK; 
}

/*
** Open a file.
*/
static int winOpen(
  sqlite3_vfs *pVfs,        /* Not used */
  const char *zName,        /* Name of the file (UTF-8) */
  sqlite3_file *id,         /* Write the SQLite file handle here */
  int flags,                /* Open mode flags */
  int *pOutFlags            /* Status return flags */
){
  HANDLE h;
  DWORD lastErrno;
  DWORD dwDesiredAccess;
  DWORD dwShareMode;
  DWORD dwCreationDisposition;
  DWORD dwFlagsAndAttributes = 0;
#if SQLITE_OS_WINCE
  int isTemp = 0;
#endif
  winFile *pFile = (winFile*)id;
  void *zConverted;              /* Filename in OS encoding */
  const char *zUtf8Name = zName; /* Filename in UTF-8 encoding */
  int cnt = 0;

  /* If argument zPath is a NULL pointer, this function is required to open
  ** a temporary file. Use this buffer to store the file name in.
  */
  char zTmpname[MAX_PATH+2];     /* Buffer used to create temp filename */

  int rc = SQLITE_OK;            /* Function Return Code */
#if !defined(NDEBUG) || SQLITE_OS_WINCE
  int eType = flags&0xFFFFFF00;  /* Type of file to open */
#endif

  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);

  pFile->h = INVALID_HANDLE_VALUE;

  /* If the second argument to this function is NULL, generate a 
  ** temporary file name to use 
  */
  if( !zUtf8Name ){
    assert(isDelete && !isOpenJournal);
    rc = getTempname(MAX_PATH+2, zTmpname);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    zUtf8Name = zTmpname;
  }

  /* Database filenames are double-zero terminated if they are not
  ** URIs with parameters.  Hence, they can always be passed into
  ** sqlite3_uri_parameter().
  */
  assert( (eType!=SQLITE_OPEN_MAIN_DB) || (flags & SQLITE_OPEN_URI) ||
        zUtf8Name[strlen(zUtf8Name)+1]==0 );

  /* Convert the filename to the system encoding. */
  zConverted = convertUtf8Filename(zUtf8Name);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM;
  }

  if( isReadWrite ){
    dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
  }else{
    dwDesiredAccess = GENERIC_READ;
  }

  /* Reports from the internet are that performance is always
  ** better if FILE_FLAG_RANDOM_ACCESS is used.  Ticket #2699. */
#if SQLITE_OS_WINCE
  dwFlagsAndAttributes |= FILE_FLAG_RANDOM_ACCESS;
#endif

  if( isNT() ){
    while( (h = osCreateFileW((LPCWSTR)zConverted,
                              dwDesiredAccess,
                              dwShareMode, NULL,
                              dwCreationDisposition,
                              dwFlagsAndAttributes,
                              NULL))==INVALID_HANDLE_VALUE &&
                              retryIoerr(&cnt, &lastErrno) ){}
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    while( (h = osCreateFileA((LPCSTR)zConverted,
                              dwDesiredAccess,
                              dwShareMode, NULL,
                              dwCreationDisposition,
                              dwFlagsAndAttributes,
                              NULL))==INVALID_HANDLE_VALUE &&
                              retryIoerr(&cnt, &lastErrno) ){}
#endif
  }

  logIoerr(cnt);

  OSTRACE(("OPEN %d %s 0x%lx %s\n", 
           h, zName, dwDesiredAccess, 
           h==INVALID_HANDLE_VALUE ? "failed" : "ok"));

  if( h==INVALID_HANDLE_VALUE ){
    pFile->lastErrno = lastErrno;
    winLogError(SQLITE_CANTOPEN, pFile->lastErrno, "winOpen", zUtf8Name);
    sqlite3_free(zConverted);
    if( isReadWrite && !isExclusive ){
      return winOpen(pVfs, zName, id, 
             ((flags|SQLITE_OPEN_READONLY)&~(SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE)), pOutFlags);
    }else{
      return SQLITE_CANTOPEN_BKPT;
    }
  }

  memset(pFile, 0, sizeof(*pFile));
  pFile->pMethod = &winIoMethod;
  pFile->h = h;
  pFile->lastErrno = NO_ERROR;
  pFile->pVfs = pVfs;
  pFile->pShm = 0;
  pFile->zPath = zName;
  if( sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE) ){
    pFile->ctrlFlags |= WINFILE_PSOW;
  }

#if SQLITE_OS_WINCE
  if( isReadWrite && eType==SQLITE_OPEN_MAIN_DB
       && !winceCreateLock(zName, pFile)
  ){
    osCloseHandle(h);
    sqlite3_free(zConverted);
    return SQLITE_CANTOPEN_BKPT;
  }
  if( isTemp ){
    pFile->zDeleteOnClose = zConverted;
  }else
#endif
  {
    sqlite3_free(zConverted);
  }

  OpenCounter(+1);
  return rc;
}

/*
** Delete the named file.
**
** Note that Windows does not allow a file to be deleted if some other
** process has it open.  Sometimes a virus scanner or indexing program
** will open a journal file shortly after it is created in order to do
** whatever it does.  While this other process is holding the
** file open, we will be unable to delete it.  To work around this
** problem, we delay 100 milliseconds and try to delete again.  Up
** to MX_DELETION_ATTEMPTs deletion attempts are run before giving
** up and returning an error.
*/
static int winDelete(
  sqlite3_vfs *pVfs,          /* Not used on win32 */
  const char *zFilename,      /* Name of file to delete */
  int syncDir                 /* Not used on win32 */
){
  int cnt = 0;
  int rc;
  DWORD lastErrno;
  void *zConverted;
  UNUSED_PARAMETER(pVfs);
  UNUSED_PARAMETER(syncDir);

  SimulateIOError(return SQLITE_IOERR_DELETE);
  zConverted = convertUtf8Filename(zFilename);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM;
  }
  if( isNT() ){
    rc = 1;
    while( osGetFileAttributesW(zConverted)!=INVALID_FILE_ATTRIBUTES &&
         (rc = osDeleteFileW(zConverted))==0 && retryIoerr(&cnt, &lastErrno) ){}
    rc = rc ? SQLITE_OK : SQLITE_ERROR;
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    rc = 1;
    while( osGetFileAttributesA(zConverted)!=INVALID_FILE_ATTRIBUTES &&
         (rc = osDeleteFileA(zConverted))==0 && retryIoerr(&cnt, &lastErrno) ){}
    rc = rc ? SQLITE_OK : SQLITE_ERROR;
#endif
  }
  if( rc ){
    rc = winLogError(SQLITE_IOERR_DELETE, lastErrno,
             "winDelete", zFilename);
  }else{
    logIoerr(cnt);
  }
  sqlite3_free(zConverted);
  OSTRACE(("DELETE \"%s\" %s\n", zFilename, (rc ? "failed" : "ok" )));
  return rc;
}

/*
** Check the existance and status of a file.
*/
static int winAccess(
  sqlite3_vfs *pVfs,         /* Not used on win32 */
  const char *zFilename,     /* Name of file to check */
  int flags,                 /* Type of test to make on this file */
  int *pResOut               /* OUT: Result */
){
  DWORD attr;
  int rc = 0;
  DWORD lastErrno;
  void *zConverted;
  UNUSED_PARAMETER(pVfs);

  SimulateIOError( return SQLITE_IOERR_ACCESS; );
  zConverted = convertUtf8Filename(zFilename);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM;
  }
  if( isNT() ){
    int cnt = 0;
    WIN32_FILE_ATTRIBUTE_DATA sAttrData;
    memset(&sAttrData, 0, sizeof(sAttrData));
    while( !(rc = osGetFileAttributesExW((LPCWSTR)zConverted,
                             GetFileExInfoStandard, 
                             &sAttrData)) && retryIoerr(&cnt, &lastErrno) ){}
    if( rc ){
      /* For an SQLITE_ACCESS_EXISTS query, treat a zero-length file
      ** as if it does not exist.
      */
      if(    flags==SQLITE_ACCESS_EXISTS
          && sAttrData.nFileSizeHigh==0 
          && sAttrData.nFileSizeLow==0 ){
        attr = INVALID_FILE_ATTRIBUTES;
      }else{
        attr = sAttrData.dwFileAttributes;
      }
    }else{
      logIoerr(cnt);
      if( lastErrno!=ERROR_FILE_NOT_FOUND ){
        winLogError(SQLITE_IOERR_ACCESS, lastErrno, "winAccess", zFilename);
        sqlite3_free(zConverted);
        return SQLITE_IOERR_ACCESS;
      }else{
        attr = INVALID_FILE_ATTRIBUTES;
      }
    }
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    attr = osGetFileAttributesA((char*)zConverted);
#endif
  }
  sqlite3_free(zConverted);
  switch( flags ){
    case SQLITE_ACCESS_READ:
    case SQLITE_ACCESS_EXISTS:
      rc = attr!=INVALID_FILE_ATTRIBUTES;
      break;
    case SQLITE_ACCESS_READWRITE:
      rc = attr!=INVALID_FILE_ATTRIBUTES &&

  ** using the io-error infrastructure to test that SQLite handles this
  ** function failing. This function could fail if, for example, the
  ** current working directory has been unlinked.
  */
  SimulateIOError( return SQLITE_ERROR );
  UNUSED_PARAMETER(nFull);
  zConverted = convertUtf8Filename(zRelative);
  if( zConverted==0 ){
    return SQLITE_IOERR_NOMEM;
  }
  if( isNT() ){
    LPWSTR zTemp;
    nByte = osGetFullPathNameW((LPCWSTR)zConverted, 0, 0, 0) + 3;
    zTemp = sqlite3_malloc( nByte*sizeof(zTemp[0]) );
    if( zTemp==0 ){
      sqlite3_free(zConverted);
      return SQLITE_IOERR_NOMEM;
    }
    osGetFullPathNameW((LPCWSTR)zConverted, nByte, zTemp, 0);
    sqlite3_free(zConverted);
    zOut = unicodeToUtf8(zTemp);
    sqlite3_free(zTemp);
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    char *zTemp;
    nByte = osGetFullPathNameA((char*)zConverted, 0, 0, 0) + 3;
    zTemp = sqlite3_malloc( nByte*sizeof(zTemp[0]) );
    if( zTemp==0 ){
      sqlite3_free(zConverted);
      return SQLITE_IOERR_NOMEM;
    }
    osGetFullPathNameA((char*)zConverted, nByte, zTemp, 0);
    sqlite3_free(zConverted);
    zOut = sqlite3_win32_mbcs_to_utf8(zTemp);
    sqlite3_free(zTemp);
#endif
  }
  if( zOut ){
    sqlite3_snprintf(pVfs->mxPathname, zFull, "%s", zOut);
    sqlite3_free(zOut);
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR_NOMEM;
  }
#endif






































































}

#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
/*
** Interfaces for opening a shared library, finding entry points
** within the shared library, and closing the shared library.
*/
static void *winDlOpen(sqlite3_vfs *pVfs, const char *zFilename){
  HANDLE h;
  void *zConverted = convertUtf8Filename(zFilename);
  UNUSED_PARAMETER(pVfs);
  if( zConverted==0 ){
    return 0;
  }
  if( isNT() ){
    h = osLoadLibraryW((LPCWSTR)zConverted);
/* isNT() is 1 if SQLITE_OS_WINCE==1, so this else is never executed. 
** Since the ANSI version of these Windows API do not exist for WINCE,
** it's important to not reference them for WINCE builds.
*/
#if SQLITE_OS_WINCE==0
  }else{
    h = osLoadLibraryA((char*)zConverted);
#endif
  }
  sqlite3_free(zConverted);
  return (void*)h;
}
static void winDlError(sqlite3_vfs *pVfs, int nBuf, char *zBufOut){
  UNUSED_PARAMETER(pVfs);
  getLastErrorMsg(osGetLastError(), nBuf, zBufOut);
}
static void (*winDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol))(void){
  UNUSED_PARAMETER(pVfs);


  return (void(*)(void))osGetProcAddressA((HANDLE)pHandle, zSymbol);





}
static void winDlClose(sqlite3_vfs *pVfs, void *pHandle){
  UNUSED_PARAMETER(pVfs);
  osFreeLibrary((HANDLE)pHandle);
}
#else /* if SQLITE_OMIT_LOAD_EXTENSION is defined: */
  #define winDlOpen  0
  #define winDlError 0
  #define winDlSym   0
  #define winDlClose 0
#endif

  UNUSED_PARAMETER(pVfs);
#if defined(SQLITE_TEST)
  n = nBuf;
  memset(zBuf, 0, nBuf);
#else
  if( sizeof(SYSTEMTIME)<=nBuf-n ){
    SYSTEMTIME x;
    osGetSystemTime(&x);
    memcpy(&zBuf[n], &x, sizeof(x));
    n += sizeof(x);
  }
  if( sizeof(DWORD)<=nBuf-n ){
    DWORD pid = osGetCurrentProcessId();
    memcpy(&zBuf[n], &pid, sizeof(pid));
    n += sizeof(pid);
  }
  if( sizeof(DWORD)<=nBuf-n ){
    DWORD cnt = osGetTickCount();
    memcpy(&zBuf[n], &cnt, sizeof(cnt));
    n += sizeof(cnt);
  }
  if( sizeof(LARGE_INTEGER)<=nBuf-n ){
    LARGE_INTEGER i;
    osQueryPerformanceCounter(&i);
    memcpy(&zBuf[n], &i, sizeof(i));
    n += sizeof(i);
  }
#endif
  return n;
}


/*
** Sleep for a little while.  Return the amount of time slept.
*/
static int winSleep(sqlite3_vfs *pVfs, int microsec){
  osSleep((microsec+999)/1000);
  UNUSED_PARAMETER(pVfs);
  return ((microsec+999)/1000)*1000;
}

/*
** The following variable, if set to a non-zero value, is interpreted as
** the number of seconds since 1970 and is used to set the result of

#endif
  /* 2^32 - to avoid use of LL and warnings in gcc */
  static const sqlite3_int64 max32BitValue = 
      (sqlite3_int64)2000000000 + (sqlite3_int64)2000000000 + (sqlite3_int64)294967296;

#if SQLITE_OS_WINCE
  SYSTEMTIME time;
  osGetSystemTime(&time);
  /* if SystemTimeToFileTime() fails, it returns zero. */
  if (!osSystemTimeToFileTime(&time,&ft)){
    return SQLITE_ERROR;
  }
#else
  osGetSystemTimeAsFileTime( &ft );
#endif

  *piNow = winFiletimeEpoch +
            ((((sqlite3_int64)ft.dwHighDateTime)*max32BitValue) + 
               (sqlite3_int64)ft.dwLowDateTime)/(sqlite3_int64)10000;

#ifdef SQLITE_TEST

    *prNow = i/86400000.0;
  }
  return rc;
}

/*
** The idea is that this function works like a combination of
** GetLastError() and FormatMessage() on Windows (or errno and
** strerror_r() on Unix). After an error is returned by an OS
** function, SQLite calls this function with zBuf pointing to
** a buffer of nBuf bytes. The OS layer should populate the
** buffer with a nul-terminated UTF-8 encoded error message
** describing the last IO error to have occurred within the calling
** thread.
**
** If the error message is too large for the supplied buffer,

**
** However if an error message is supplied, it will be incorporated
** by sqlite into the error message available to the user using
** sqlite3_errmsg(), possibly making IO errors easier to debug.
*/
static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
  UNUSED_PARAMETER(pVfs);
  return getLastErrorMsg(osGetLastError(), nBuf, zBuf);
}



/*
** Initialize and deinitialize the operating system interface.
*/
SQLITE_API int sqlite3_os_init(void){
  static sqlite3_vfs winVfs = {
    3,                   /* iVersion */

    winDlSym,            /* xDlSym */
    winDlClose,          /* xDlClose */
    winRandomness,       /* xRandomness */
    winSleep,            /* xSleep */
    winCurrentTime,      /* xCurrentTime */
    winGetLastError,     /* xGetLastError */
    winCurrentTimeInt64, /* xCurrentTimeInt64 */
    winSetSystemCall,    /* xSetSystemCall */
    winGetSystemCall,    /* xGetSystemCall */
    winNextSystemCall,   /* xNextSystemCall */
  };

  /* Double-check that the aSyscall[] array has been constructed
  ** correctly.  See ticket [bb3a86e890c8e96ab] */
  assert( ArraySize(aSyscall)==60 );

#ifndef SQLITE_OMIT_WAL
  /* get memory map allocation granularity */
  memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
  osGetSystemInfo(&winSysInfo);
  assert(winSysInfo.dwAllocationGranularity > 0);
#endif

  sqlite3_vfs_register(&winVfs, 1);
  return SQLITE_OK; 
}

SQLITE_API int sqlite3_os_end(void){ 
  return SQLITE_OK;
}

#endif /* SQLITE_OS_WIN */

/************** End of os_win.c **********************************************/

/*
** A complete page cache is an instance of this structure.
*/
struct PCache {
  PgHdr *pDirty, *pDirtyTail;         /* List of dirty pages in LRU order */
  PgHdr *pSynced;                     /* Last synced page in dirty page list */
  int nRef;                           /* Number of referenced pages */
  int szCache;                        /* Configured cache size */
  int szPage;                         /* Size of every page in this cache */
  int szExtra;                        /* Size of extra space for each page */
  int bPurgeable;                     /* True if pages are on backing store */
  int (*xStress)(void*,PgHdr*);       /* Call to try make a page clean */
  void *pStress;                      /* Argument to xStress */
  sqlite3_pcache *pCache;             /* Pluggable cache module */
  PgHdr *pPage1;                      /* Reference to page 1 */

*/
static void pcacheUnpin(PgHdr *p){
  PCache *pCache = p->pCache;
  if( pCache->bPurgeable ){
    if( p->pgno==1 ){
      pCache->pPage1 = 0;
    }
    sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, p->pPage, 0);
  }
}

/*************************************************** General Interfaces ******
**
** Initialize and shutdown the page cache subsystem. Neither of these 
** functions are threadsafe.
*/
SQLITE_PRIVATE int sqlite3PcacheInitialize(void){
  if( sqlite3GlobalConfig.pcache2.xInit==0 ){
    /* IMPLEMENTATION-OF: R-26801-64137 If the xInit() method is NULL, then the
    ** built-in default page cache is used instead of the application defined
    ** page cache. */
    sqlite3PCacheSetDefault();
  }
  return sqlite3GlobalConfig.pcache2.xInit(sqlite3GlobalConfig.pcache2.pArg);
}
SQLITE_PRIVATE void sqlite3PcacheShutdown(void){
  if( sqlite3GlobalConfig.pcache2.xShutdown ){
    /* IMPLEMENTATION-OF: R-26000-56589 The xShutdown() method may be NULL. */
    sqlite3GlobalConfig.pcache2.xShutdown(sqlite3GlobalConfig.pcache2.pArg);
  }
}

/*
** Return the size in bytes of a PCache object.
*/
SQLITE_PRIVATE int sqlite3PcacheSize(void){ return sizeof(PCache); }

){
  memset(p, 0, sizeof(PCache));
  p->szPage = szPage;
  p->szExtra = szExtra;
  p->bPurgeable = bPurgeable;
  p->xStress = xStress;
  p->pStress = pStress;
  p->szCache = 100;
}

/*
** Change the page size for PCache object. The caller must ensure that there
** are no outstanding page references when this function is called.
*/
SQLITE_PRIVATE void sqlite3PcacheSetPageSize(PCache *pCache, int szPage){
  assert( pCache->nRef==0 && pCache->pDirty==0 );
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
    pCache->pCache = 0;
    pCache->pPage1 = 0;
  }
  pCache->szPage = szPage;
}

/*
** Compute the number of pages of cache requested.
*/
static int numberOfCachePages(PCache *p){
  if( p->szCache>=0 ){
    return p->szCache;
  }else{
    return (int)((-1024*(i64)p->szCache)/(p->szPage+p->szExtra));
  }
}

/*
** Try to obtain a page from the cache.
*/
SQLITE_PRIVATE int sqlite3PcacheFetch(
  PCache *pCache,       /* Obtain the page from this cache */
  Pgno pgno,            /* Page number to obtain */
  int createFlag,       /* If true, create page if it does not exist already */
  PgHdr **ppPage        /* Write the page here */
){
  sqlite3_pcache_page *pPage = 0;
  PgHdr *pPgHdr = 0;
  int eCreate;

  assert( pCache!=0 );
  assert( createFlag==1 || createFlag==0 );
  assert( pgno>0 );

  /* If the pluggable cache (sqlite3_pcache*) has not been allocated,
  ** allocate it now.
  */
  if( !pCache->pCache && createFlag ){
    sqlite3_pcache *p;


    p = sqlite3GlobalConfig.pcache2.xCreate(
        pCache->szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable
    );
    if( !p ){
      return SQLITE_NOMEM;
    }
    sqlite3GlobalConfig.pcache2.xCachesize(p, numberOfCachePages(pCache));
    pCache->pCache = p;
  }

  eCreate = createFlag * (1 + (!pCache->bPurgeable || !pCache->pDirty));
  if( pCache->pCache ){
    pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
  }

  if( !pPage && eCreate==1 ){
    PgHdr *pPg;

    /* Find a dirty page to write-out and recycle. First try to find a 
    ** page that does not require a journal-sync (one with PGHDR_NEED_SYNC

    if( pPg ){
      int rc;
#ifdef SQLITE_LOG_CACHE_SPILL
      sqlite3_log(SQLITE_FULL, 
                  "spill page %d making room for %d - cache used: %d/%d",
                  pPg->pgno, pgno,
                  sqlite3GlobalConfig.pcache.xPagecount(pCache->pCache),
                  numberOfCachePages(pCache));
#endif
      rc = pCache->xStress(pCache->pStress, pPg);
      if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
        return rc;
      }
    }

    pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, 2);
  }

  if( pPage ){
    pPgHdr = (PgHdr *)pPage->pExtra;

    if( !pPgHdr->pPage ){
      memset(pPgHdr, 0, sizeof(PgHdr));
      pPgHdr->pPage = pPage;
      pPgHdr->pData = pPage->pBuf;
      pPgHdr->pExtra = (void *)&pPgHdr[1];
      memset(pPgHdr->pExtra, 0, pCache->szExtra);
      pPgHdr->pCache = pCache;
      pPgHdr->pgno = pgno;
    }
    assert( pPgHdr->pCache==pCache );
    assert( pPgHdr->pgno==pgno );
    assert( pPgHdr->pData==pPage->pBuf );
    assert( pPgHdr->pExtra==(void *)&pPgHdr[1] );

    if( 0==pPgHdr->nRef ){
      pCache->nRef++;
    }
    pPgHdr->nRef++;
    if( pgno==1 ){
      pCache->pPage1 = pPgHdr;
    }
  }
  *ppPage = pPgHdr;
  return (pPgHdr==0 && eCreate) ? SQLITE_NOMEM : SQLITE_OK;
}

/*
** Decrement the reference count on a page. If the page is clean and the
** reference count drops to 0, then it is made elible for recycling.
*/
SQLITE_PRIVATE void sqlite3PcacheRelease(PgHdr *p){

    pcacheRemoveFromDirtyList(p);
  }
  pCache = p->pCache;
  pCache->nRef--;
  if( p->pgno==1 ){
    pCache->pPage1 = 0;
  }
  sqlite3GlobalConfig.pcache2.xUnpin(pCache->pCache, p->pPage, 1);
}

/*
** Make sure the page is marked as dirty. If it isn't dirty already,
** make it so.
*/
SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr *p){

/*
** Change the page number of page p to newPgno. 
*/
SQLITE_PRIVATE void sqlite3PcacheMove(PgHdr *p, Pgno newPgno){
  PCache *pCache = p->pCache;
  assert( p->nRef>0 );
  assert( newPgno>0 );
  sqlite3GlobalConfig.pcache2.xRekey(pCache->pCache, p->pPage, p->pgno,newPgno);
  p->pgno = newPgno;
  if( (p->flags&PGHDR_DIRTY) && (p->flags&PGHDR_NEED_SYNC) ){
    pcacheRemoveFromDirtyList(p);
    pcacheAddToDirtyList(p);
  }
}

        sqlite3PcacheMakeClean(p);
      }
    }
    if( pgno==0 && pCache->pPage1 ){
      memset(pCache->pPage1->pData, 0, pCache->szPage);
      pgno = 1;
    }
    sqlite3GlobalConfig.pcache2.xTruncate(pCache->pCache, pgno+1);
  }
}

/*
** Close a cache.
*/
SQLITE_PRIVATE void sqlite3PcacheClose(PCache *pCache){
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xDestroy(pCache->pCache);
  }
}

/* 
** Discard the contents of the cache.
*/
SQLITE_PRIVATE void sqlite3PcacheClear(PCache *pCache){

/* 
** Return the total number of pages in the cache.
*/
SQLITE_PRIVATE int sqlite3PcachePagecount(PCache *pCache){
  int nPage = 0;
  if( pCache->pCache ){
    nPage = sqlite3GlobalConfig.pcache2.xPagecount(pCache->pCache);
  }
  return nPage;
}

#ifdef SQLITE_TEST
/*
** Get the suggested cache-size value.
*/
SQLITE_PRIVATE int sqlite3PcacheGetCachesize(PCache *pCache){
  return numberOfCachePages(pCache);
}
#endif

/*
** Set the suggested cache-size value.
*/
SQLITE_PRIVATE void sqlite3PcacheSetCachesize(PCache *pCache, int mxPage){
  pCache->szCache = mxPage;
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xCachesize(pCache->pCache,
                                           numberOfCachePages(pCache));
  }
}

/*
** Free up as much memory as possible from the page cache.
*/
SQLITE_PRIVATE void sqlite3PcacheShrink(PCache *pCache){
  if( pCache->pCache ){
    sqlite3GlobalConfig.pcache2.xShrink(pCache->pCache);
  }
}

#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
/*
** For all dirty pages currently in the cache, invoke the specified
** callback. This is only used if the SQLITE_CHECK_PAGES macro is

typedef struct PCache1 PCache1;
typedef struct PgHdr1 PgHdr1;
typedef struct PgFreeslot PgFreeslot;
typedef struct PGroup PGroup;


/* Each page cache (or PCache) belongs to a PGroup.  A PGroup is a set 
** of one or more PCaches that are able to recycle each others unpinned
** pages when they are under memory pressure.  A PGroup is an instance of
** the following object.
**
** This page cache implementation works in one of two modes:
**
**   (1)  Every PCache is the sole member of its own PGroup.  There is
**        one PGroup per PCache.
**
**   (2)  There is a single global PGroup that all PCaches are a member
**        of.
**
** Mode 1 uses more memory (since PCache instances are not able to rob
** unused pages from other PCaches) but it also operates without a mutex,
** and is therefore often faster.  Mode 2 requires a mutex in order to be
** threadsafe, but recycles pages more efficiently.
**
** For mode (1), PGroup.mutex is NULL.  For mode (2) there is only a single
** PGroup which is the pcache1.grp global variable and its mutex is
** SQLITE_MUTEX_STATIC_LRU.
*/
struct PGroup {
  sqlite3_mutex *mutex;          /* MUTEX_STATIC_LRU or NULL */
  unsigned int nMaxPage;         /* Sum of nMax for purgeable caches */
  unsigned int nMinPage;         /* Sum of nMin for purgeable caches */
  unsigned int mxPinned;         /* nMaxpage + 10 - nMinPage */
  unsigned int nCurrentPage;     /* Number of purgeable pages allocated */
  PgHdr1 *pLruHead, *pLruTail;   /* LRU list of unpinned pages */
};

/* Each page cache is an instance of the following object.  Every
** open database file (including each in-memory database and each
** temporary or transient database) has a single page cache which
** is an instance of this object.
**
** Pointers to structures of this type are cast and returned as 
** opaque sqlite3_pcache* handles.
*/
struct PCache1 {
  /* Cache configuration parameters. Page size (szPage) and the purgeable
  ** flag (bPurgeable) are set when the cache is created. nMax may be 
  ** modified at any time by a call to the pcache1Cachesize() method.
  ** The PGroup mutex must be held when accessing nMax.
  */
  PGroup *pGroup;                     /* PGroup this cache belongs to */
  int szPage;                         /* Size of allocated pages in bytes */
  int szExtra;                        /* Size of extra space in bytes */
  int bPurgeable;                     /* True if cache is purgeable */
  unsigned int nMin;                  /* Minimum number of pages reserved */
  unsigned int nMax;                  /* Configured "cache_size" value */
  unsigned int n90pct;                /* nMax*9/10 */

  /* Hash table of all pages. The following variables may only be accessed
  ** when the accessor is holding the PGroup mutex.
  */
  unsigned int nRecyclable;           /* Number of pages in the LRU list */
  unsigned int nPage;                 /* Total number of pages in apHash */
  unsigned int nHash;                 /* Number of slots in apHash[] */
  PgHdr1 **apHash;                    /* Hash table for fast lookup by key */

  unsigned int iMaxKey;               /* Largest key seen since xTruncate() */
};

/*
** Each cache entry is represented by an instance of the following 
** structure. Unless SQLITE_PCACHE_SEPARATE_HEADER is defined, a buffer of
** PgHdr1.pCache->szPage bytes is allocated directly before this structure 
** in memory.

*/
struct PgHdr1 {
  sqlite3_pcache_page page;
  unsigned int iKey;             /* Key value (page number) */
  PgHdr1 *pNext;                 /* Next in hash table chain */
  PCache1 *pCache;               /* Cache that currently owns this page */
  PgHdr1 *pLruNext;              /* Next in LRU list of unpinned pages */
  PgHdr1 *pLruPrev;              /* Previous in LRU list of unpinned pages */
};

/*
** All code in this file should access the global structure above via the
** alias "pcache1". This ensures that the WSD emulation is used when
** compiling for systems that do not support real WSD.
*/
#define pcache1 (GLOBAL(struct PCacheGlobal, pcache1_g))
















/*
** Macros to enter and leave the PCache LRU mutex.
*/
#define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex)
#define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex)

/******************************************************************************/

  }
  return p;
}

/*
** Free an allocated buffer obtained from pcache1Alloc().
*/
static int pcache1Free(void *p){
  int nFreed = 0;
  if( p==0 ) return 0;
  if( p>=pcache1.pStart && p<pcache1.pEnd ){
    PgFreeslot *pSlot;
    sqlite3_mutex_enter(pcache1.mutex);
    sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, -1);
    pSlot = (PgFreeslot*)p;
    pSlot->pNext = pcache1.pFree;
    pcache1.pFree = pSlot;
    pcache1.nFreeSlot++;
    pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve;
    assert( pcache1.nFreeSlot<=pcache1.nSlot );
    sqlite3_mutex_leave(pcache1.mutex);
  }else{

    assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) );
    sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
    nFreed = sqlite3MallocSize(p);
    sqlite3_mutex_enter(pcache1.mutex);
    sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, -nFreed);
    sqlite3_mutex_leave(pcache1.mutex);
    sqlite3_free(p);
  }
  return nFreed;
}

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** Return the size of a pcache allocation
*/
static int pcache1MemSize(void *p){

}
#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */

/*
** Allocate a new page object initially associated with cache pCache.
*/
static PgHdr1 *pcache1AllocPage(PCache1 *pCache){

  PgHdr1 *p = 0;
  void *pPg;

  /* The group mutex must be released before pcache1Alloc() is called. This
  ** is because it may call sqlite3_release_memory(), which assumes that 
  ** this mutex is not held. */
  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
  pcache1LeaveMutex(pCache->pGroup);
#ifdef SQLITE_PCACHE_SEPARATE_HEADER
  pPg = pcache1Alloc(pCache->szPage);
  p = sqlite3Malloc(sizeof(PgHdr1) + pCache->szExtra);
  if( !pPg || !p ){
    pcache1Free(pPg);
    sqlite3_free(p);
    pPg = 0;
  }
#else
  pPg = pcache1Alloc(sizeof(PgHdr1) + pCache->szPage + pCache->szExtra);
  p = (PgHdr1 *)&((u8 *)pPg)[pCache->szPage];
#endif
  pcache1EnterMutex(pCache->pGroup);

  if( pPg ){
    p->page.pBuf = pPg;
    p->page.pExtra = &p[1];
    if( pCache->bPurgeable ){
      pCache->pGroup->nCurrentPage++;
    }
    return p;
  }
  return 0;
}

/*
** Free a page object allocated by pcache1AllocPage().
**
** The pointer is allowed to be NULL, which is prudent.  But it turns out
** that the current implementation happens to never call this routine
** with a NULL pointer, so we mark the NULL test with ALWAYS().
*/
static void pcache1FreePage(PgHdr1 *p){
  if( ALWAYS(p) ){
    PCache1 *pCache = p->pCache;
    assert( sqlite3_mutex_held(p->pCache->pGroup->mutex) );
    pcache1Free(p->page.pBuf);
#ifdef SQLITE_PCACHE_SEPARATE_HEADER
    sqlite3_free(p);
#endif
    if( pCache->bPurgeable ){
      pCache->pGroup->nCurrentPage--;
    }
  }
}

/*

** If memory was allocated specifically to the page cache using
** SQLITE_CONFIG_PAGECACHE but that memory has all been used, then
** it is desirable to avoid allocating a new page cache entry because
** presumably SQLITE_CONFIG_PAGECACHE was suppose to be sufficient
** for all page cache needs and we should not need to spill the
** allocation onto the heap.
**
** Or, the heap is used for all page cache memory but the heap is
** under memory pressure, then again it is desirable to avoid
** allocating a new page cache entry in order to avoid stressing
** the heap even further.
*/
static int pcache1UnderMemoryPressure(PCache1 *pCache){
  if( pcache1.nSlot && (pCache->szPage+pCache->szExtra)<=pcache1.szSlot ){
    return pcache1.bUnderPressure;
  }else{
    return sqlite3HeapNearlyFull();
  }
}

/******************************************************************************/

}

/*
** Implementation of the sqlite3_pcache.xCreate method.
**
** Allocate a new cache.
*/
static sqlite3_pcache *pcache1Create(int szPage, int szExtra, int bPurgeable){
  PCache1 *pCache;      /* The newly created page cache */
  PGroup *pGroup;       /* The group the new page cache will belong to */
  int sz;               /* Bytes of memory required to allocate the new cache */

  /*
  ** The seperateCache variable is true if each PCache has its own private
  ** PGroup.  In other words, separateCache is true for mode (1) where no

  **      use separate caches (mode-1)
  */
#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) || SQLITE_THREADSAFE==0
  const int separateCache = 0;
#else
  int separateCache = sqlite3GlobalConfig.bCoreMutex>0;
#endif

  assert( (szPage & (szPage-1))==0 && szPage>=512 && szPage<=65536 );
  assert( szExtra < 300 );

  sz = sizeof(PCache1) + sizeof(PGroup)*separateCache;
  pCache = (PCache1 *)sqlite3_malloc(sz);
  if( pCache ){
    memset(pCache, 0, sz);
    if( separateCache ){
      pGroup = (PGroup*)&pCache[1];
      pGroup->mxPinned = 10;
    }else{
      pGroup = &pcache1.grp;
    }
    pCache->pGroup = pGroup;
    pCache->szPage = szPage;
    pCache->szExtra = szExtra;
    pCache->bPurgeable = (bPurgeable ? 1 : 0);
    if( bPurgeable ){
      pCache->nMin = 10;
      pcache1EnterMutex(pGroup);
      pGroup->nMinPage += pCache->nMin;
      pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
      pcache1LeaveMutex(pGroup);

    pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
    pCache->nMax = nMax;
    pCache->n90pct = pCache->nMax*9/10;
    pcache1EnforceMaxPage(pGroup);
    pcache1LeaveMutex(pGroup);
  }
}

/*
** Implementation of the sqlite3_pcache.xShrink method. 
**
** Free up as much memory as possible.
*/
static void pcache1Shrink(sqlite3_pcache *p){
  PCache1 *pCache = (PCache1*)p;
  if( pCache->bPurgeable ){
    PGroup *pGroup = pCache->pGroup;
    int savedMaxPage;
    pcache1EnterMutex(pGroup);
    savedMaxPage = pGroup->nMaxPage;
    pGroup->nMaxPage = 0;
    pcache1EnforceMaxPage(pGroup);
    pGroup->nMaxPage = savedMaxPage;
    pcache1LeaveMutex(pGroup);
  }
}

/*
** Implementation of the sqlite3_pcache.xPagecount method. 
*/
static int pcache1Pagecount(sqlite3_pcache *p){
  int n;
  PCache1 *pCache = (PCache1*)p;

** the value of the createFlag argument.  0 means do not allocate a new
** page.  1 means allocate a new page if space is easily available.  2 
** means to try really hard to allocate a new page.
**
** For a non-purgeable cache (a cache used as the storage for an in-memory
** database) there is really no difference between createFlag 1 and 2.  So
** the calling function (pcache.c) will never have a createFlag of 1 on
** a non-purgeable cache.
**
** There are three different approaches to obtaining space for a page,
** depending on the value of parameter createFlag (which may be 0, 1 or 2).
**
**   1. Regardless of the value of createFlag, the cache is searched for a 
**      copy of the requested page. If one is found, it is returned.
**

**
**      then attempt to recycle a page from the LRU list. If it is the right
**      size, return the recycled buffer. Otherwise, free the buffer and
**      proceed to step 5. 
**
**   5. Otherwise, allocate and return a new page buffer.
*/
static sqlite3_pcache_page *pcache1Fetch(
  sqlite3_pcache *p, 
  unsigned int iKey, 
  int createFlag
){
  unsigned int nPinned;
  PCache1 *pCache = (PCache1 *)p;
  PGroup *pGroup;
  PgHdr1 *pPage = 0;

  assert( pCache->bPurgeable || createFlag!=1 );
  assert( pCache->bPurgeable || pCache->nMin==0 );
  assert( pCache->bPurgeable==0 || pCache->nMin==10 );

  ** optimization:  The common case is to exit the module before reaching
  ** this point.
  */
#ifdef SQLITE_MUTEX_OMIT
  pGroup = pCache->pGroup;
#endif


  /* Step 3: Abort if createFlag is 1 but the cache is nearly full */
  assert( pCache->nPage >= pCache->nRecyclable );
  nPinned = pCache->nPage - pCache->nRecyclable;

  assert( pGroup->mxPinned == pGroup->nMaxPage + 10 - pGroup->nMinPage );
  assert( pCache->n90pct == pCache->nMax*9/10 );
  if( createFlag==1 && (
        nPinned>=pGroup->mxPinned
     || nPinned>=pCache->n90pct
     || pcache1UnderMemoryPressure(pCache)
  )){
    goto fetch_out;
  }

  if( pCache->nPage>=pCache->nHash && pcache1ResizeHash(pCache) ){
    goto fetch_out;
  }

  /* Step 4. Try to recycle a page. */
  if( pCache->bPurgeable && pGroup->pLruTail && (
         (pCache->nPage+1>=pCache->nMax)
      || pGroup->nCurrentPage>=pGroup->nMaxPage
      || pcache1UnderMemoryPressure(pCache)
  )){
    PCache1 *pOther;
    pPage = pGroup->pLruTail;
    pcache1RemoveFromHash(pPage);
    pcache1PinPage(pPage);
    pOther = pPage->pCache;

    /* We want to verify that szPage and szExtra are the same for pOther
    ** and pCache.  Assert that we can verify this by comparing sums. */
    assert( (pCache->szPage & (pCache->szPage-1))==0 && pCache->szPage>=512 );
    assert( pCache->szExtra<512 );
    assert( (pOther->szPage & (pOther->szPage-1))==0 && pOther->szPage>=512 );
    assert( pOther->szExtra<512 );

    if( pOther->szPage+pOther->szExtra != pCache->szPage+pCache->szExtra ){
      pcache1FreePage(pPage);
      pPage = 0;
    }else{
      pGroup->nCurrentPage -= (pOther->bPurgeable - pCache->bPurgeable);

    }
  }

  /* Step 5. If a usable page buffer has still not been found, 
  ** attempt to allocate a new one. 
  */
  if( !pPage ){
    if( createFlag==1 ) sqlite3BeginBenignMalloc();
    pPage = pcache1AllocPage(pCache);
    if( createFlag==1 ) sqlite3EndBenignMalloc();
  }

  if( pPage ){
    unsigned int h = iKey % pCache->nHash;
    pCache->nPage++;
    pPage->iKey = iKey;
    pPage->pNext = pCache->apHash[h];
    pPage->pCache = pCache;
    pPage->pLruPrev = 0;
    pPage->pLruNext = 0;
    *(void **)pPage->page.pExtra = 0;
    pCache->apHash[h] = pPage;
  }

fetch_out:
  if( pPage && iKey>pCache->iMaxKey ){
    pCache->iMaxKey = iKey;
  }
  pcache1LeaveMutex(pGroup);
  return &pPage->page;
}


/*
** Implementation of the sqlite3_pcache.xUnpin method.
**
** Mark a page as unpinned (eligible for asynchronous recycling).
*/
static void pcache1Unpin(
  sqlite3_pcache *p, 
  sqlite3_pcache_page *pPg, 
  int reuseUnlikely
){
  PCache1 *pCache = (PCache1 *)p;
  PgHdr1 *pPage = (PgHdr1 *)pPg;
  PGroup *pGroup = pCache->pGroup;
 
  assert( pPage->pCache==pCache );
  pcache1EnterMutex(pGroup);

  /* It is an error to call this function if the page is already 
  ** part of the PGroup LRU list.

}

/*
** Implementation of the sqlite3_pcache.xRekey method. 
*/
static void pcache1Rekey(
  sqlite3_pcache *p,
  sqlite3_pcache_page *pPg,
  unsigned int iOld,
  unsigned int iNew
){
  PCache1 *pCache = (PCache1 *)p;
  PgHdr1 *pPage = (PgHdr1 *)pPg;
  PgHdr1 **pp;
  unsigned int h; 
  assert( pPage->iKey==iOld );
  assert( pPage->pCache==pCache );

  pcache1EnterMutex(pCache->pGroup);

*/
static void pcache1Destroy(sqlite3_pcache *p){
  PCache1 *pCache = (PCache1 *)p;
  PGroup *pGroup = pCache->pGroup;
  assert( pCache->bPurgeable || (pCache->nMax==0 && pCache->nMin==0) );
  pcache1EnterMutex(pGroup);
  pcache1TruncateUnsafe(pCache, 0);
  assert( pGroup->nMaxPage >= pCache->nMax );
  pGroup->nMaxPage -= pCache->nMax;
  assert( pGroup->nMinPage >= pCache->nMin );
  pGroup->nMinPage -= pCache->nMin;
  pGroup->mxPinned = pGroup->nMaxPage + 10 - pGroup->nMinPage;
  pcache1EnforceMaxPage(pGroup);
  pcache1LeaveMutex(pGroup);
  sqlite3_free(pCache->apHash);
  sqlite3_free(pCache);
}

/*
** This function is called during initialization (sqlite3_initialize()) to
** install the default pluggable cache module, assuming the user has not
** already provided an alternative.
*/
SQLITE_PRIVATE void sqlite3PCacheSetDefault(void){
  static const sqlite3_pcache_methods2 defaultMethods = {
    1,                       /* iVersion */
    0,                       /* pArg */
    pcache1Init,             /* xInit */
    pcache1Shutdown,         /* xShutdown */
    pcache1Create,           /* xCreate */
    pcache1Cachesize,        /* xCachesize */
    pcache1Pagecount,        /* xPagecount */
    pcache1Fetch,            /* xFetch */
    pcache1Unpin,            /* xUnpin */
    pcache1Rekey,            /* xRekey */
    pcache1Truncate,         /* xTruncate */
    pcache1Destroy,          /* xDestroy */
    pcache1Shrink            /* xShrink */
  };
  sqlite3_config(SQLITE_CONFIG_PCACHE2, &defaultMethods);
}

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** This function is called to free superfluous dynamically allocated memory
** held by the pager system. Memory in use by any SQLite pager allocated
** by the current thread may be sqlite3_free()ed.
**
** nReq is the number of bytes of memory required. Once this much has
** been released, the function returns. The return value is the total number 
** of bytes of memory released.
*/
SQLITE_PRIVATE int sqlite3PcacheReleaseMemory(int nReq){
  int nFree = 0;
  assert( sqlite3_mutex_notheld(pcache1.grp.mutex) );
  assert( sqlite3_mutex_notheld(pcache1.mutex) );
  if( pcache1.pStart==0 ){
    PgHdr1 *p;
    pcache1EnterMutex(&pcache1.grp);
    while( (nReq<0 || nFree<nReq) && ((p=pcache1.grp.pLruTail)!=0) ){
      nFree += pcache1MemSize(p->page.pBuf);
#ifdef SQLITE_PCACHE_SEPARATE_HEADER
      nFree += sqlite3MemSize(p);
#endif
      pcache1PinPage(p);
      pcache1RemoveFromHash(p);
      pcache1FreePage(p);
    }
    pcache1LeaveMutex(&pcache1.grp);
  }
  return nFree;

){
  PgHdr1 *p;
  int nRecyclable = 0;
  for(p=pcache1.grp.pLruHead; p; p=p->pLruNext){
    nRecyclable++;
  }
  *pnCurrent = pcache1.grp.nCurrentPage;
  *pnMax = (int)pcache1.grp.nMaxPage;
  *pnMin = (int)pcache1.grp.nMinPage;
  *pnRecyclable = nRecyclable;
}
#endif

/************** End of pcache1.c *********************************************/
/************** Begin file rowset.c ******************************************/
/*

** the implementation of each function in log.c for further details.
*/

#ifndef _WAL_H_
#define _WAL_H_


/* Additional values that can be added to the sync_flags argument of
** sqlite3WalFrames():
*/
#define WAL_SYNC_TRANSACTIONS  0x20   /* Sync at the end of each transaction */
#define SQLITE_SYNC_MASK       0x13   /* Mask off the SQLITE_SYNC_* values */

#ifdef SQLITE_OMIT_WAL
# define sqlite3WalOpen(x,y,z)                   0
# define sqlite3WalLimit(x,y)
# define sqlite3WalClose(w,x,y,z)                0
# define sqlite3WalBeginReadTransaction(y,z)     0
# define sqlite3WalEndReadTransaction(z)
# define sqlite3WalRead(v,w,x,y,z)               0

  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
  u8 journalMode;             /* One of the PAGER_JOURNALMODE_* values */
  u8 useJournal;              /* Use a rollback journal on this file */
  u8 noReadlock;              /* Do not bother to obtain readlocks */
  u8 noSync;                  /* Do not sync the journal if true */
  u8 fullSync;                /* Do extra syncs of the journal for robustness */
  u8 ckptSyncFlags;           /* SYNC_NORMAL or SYNC_FULL for checkpoint */
  u8 walSyncFlags;            /* SYNC_NORMAL or SYNC_FULL for wal writes */
  u8 syncFlags;               /* SYNC_NORMAL or SYNC_FULL otherwise */
  u8 tempFile;                /* zFilename is a temporary file */
  u8 readOnly;                /* True for a read-only database */
  u8 memDb;                   /* True to inhibit all file I/O */

  /**************************************************************************
  ** The following block contains those class members that change during

#ifndef SQLITE_OMIT_WAL
static int pagerUseWal(Pager *pPager){
  return (pPager->pWal!=0);
}
#else
# define pagerUseWal(x) 0
# define pagerRollbackWal(x) 0
# define pagerWalFrames(v,w,x,y) 0
# define pagerOpenWalIfPresent(z) SQLITE_OK
# define pagerBeginReadTransaction(z) SQLITE_OK
#endif

#ifndef NDEBUG 
/*
** Usage:

    assert( pPager->eLock==EXCLUSIVE_LOCK );
    /* TODO: Is it safe to use Pager.dbFileSize here? */
    rc = sqlite3OsFileSize(pPager->fd, &currentSize);
    newSize = szPage*(i64)nPage;
    if( rc==SQLITE_OK && currentSize!=newSize ){
      if( currentSize>newSize ){
        rc = sqlite3OsTruncate(pPager->fd, newSize);
      }else if( (currentSize+szPage)<=newSize ){
        char *pTmp = pPager->pTmpSpace;
        memset(pTmp, 0, szPage);

        testcase( (newSize-szPage) == currentSize );
        testcase( (newSize-szPage) >  currentSize );
        rc = sqlite3OsWrite(pPager->fd, pTmp, szPage, newSize-szPage);
      }
      if( rc==SQLITE_OK ){
        pPager->dbFileSize = nPage;
      }

**
** For temporary files the effective sector size is always 512 bytes.
**
** Otherwise, for non-temporary files, the effective sector size is
** the value returned by the xSectorSize() method rounded up to 32 if
** it is less than 32, or rounded down to MAX_SECTOR_SIZE if it
** is greater than MAX_SECTOR_SIZE.
**
** If the file has the SQLITE_IOCAP_POWERSAFE_OVERWRITE property, then set
** the effective sector size to its minimum value (512).  The purpose of
** pPager->sectorSize is to define the "blast radius" of bytes that
** might change if a crash occurs while writing to a single byte in
** that range.  But with POWERSAFE_OVERWRITE, the blast radius is zero
** (that is what POWERSAFE_OVERWRITE means), so we minimize the sector
** size.  For backwards compatibility of the rollback journal file format,
** we cannot reduce the effective sector size below 512.
*/
static void setSectorSize(Pager *pPager){
  assert( isOpen(pPager->fd) || pPager->tempFile );

  if( pPager->tempFile
   || (sqlite3OsDeviceCharacteristics(pPager->fd) & 
              SQLITE_IOCAP_POWERSAFE_OVERWRITE)!=0
  ){
    /* Sector size doesn't matter for temporary files. Also, the file
    ** may not have been opened yet, in which case the OsSectorSize()
    ** call will segfault. */

    pPager->sectorSize = 512;
  }else{
    pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
    if( pPager->sectorSize<32 ){
      pPager->sectorSize = 512;
    }
    if( pPager->sectorSize>MAX_SECTOR_SIZE ){
      assert( MAX_SECTOR_SIZE>=512 );
      pPager->sectorSize = MAX_SECTOR_SIZE;
    }
  }
}

/*
** Playback the journal and thus restore the database file to
** the state it was in before we started making changes.  
**

end_playback:
  /* Following a rollback, the database file should be back in its original
  ** state prior to the start of the transaction, so invoke the
  ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
  ** assertion that the transaction counter was modified.
  */
#ifdef SQLITE_DEBUG
  if( pPager->fd->pMethods ){
    sqlite3OsFileControlHint(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0);

  }
#endif

  /* If this playback is happening automatically as a result of an IO or 
  ** malloc error that occurred after the change-counter was updated but 
  ** before the transaction was committed, then the change-counter 
  ** modification may just have been reverted. If this happens in exclusive 
  ** mode, then subsequent transactions performed by the connection will not
  ** update the change-counter at all. This may lead to cache inconsistency

** The list of pages passed into this routine is always sorted by page number.
** Hence, if page 1 appears anywhere on the list, it will be the first page.
*/ 
static int pagerWalFrames(
  Pager *pPager,                  /* Pager object */
  PgHdr *pList,                   /* List of frames to log */
  Pgno nTruncate,                 /* Database size after this commit */
  int isCommit                    /* True if this is a commit */

){
  int rc;                         /* Return code */
#if defined(SQLITE_DEBUG) || defined(SQLITE_CHECK_PAGES)
  PgHdr *p;                       /* For looping over pages */
#endif

  assert( pPager->pWal );

      if( p->pgno<=nTruncate ) ppNext = &p->pDirty;
    }
    assert( pList );
  }

  if( pList->pgno==1 ) pager_write_changecounter(pList);
  rc = sqlite3WalFrames(pPager->pWal, 
      pPager->pageSize, pList, nTruncate, isCommit, pPager->walSyncFlags
  );
  if( rc==SQLITE_OK && pPager->pBackup ){
    PgHdr *p;
    for(p=pList; p; p=p->pDirty){
      sqlite3BackupUpdate(pPager->pBackup, p->pgno, (u8 *)p->pData);
    }
  }

    assert( isOpen(pPager->fd) || pPager->tempFile );
    if( isOpen(pPager->fd) ){
      int rc = sqlite3OsFileSize(pPager->fd, &n);
      if( rc!=SQLITE_OK ){
        return rc;
      }
    }
    nPage = (Pgno)((n+pPager->pageSize-1) / pPager->pageSize);



  }

  /* If the current number of pages in the file is greater than the
  ** configured maximum pager number, increase the allowed limit so
  ** that the file can be read.
  */
  if( nPage>pPager->mxPgno ){

  /* Finally,  rollback pages from the sub-journal.  Page that were
  ** previously rolled back out of the main journal (and are hence in pDone)
  ** will be skipped.  Out-of-range pages are also skipped.
  */
  if( pSavepoint ){
    u32 ii;            /* Loop counter */
    i64 offset = (i64)pSavepoint->iSubRec*(4+pPager->pageSize);

    if( pagerUseWal(pPager) ){
      rc = sqlite3WalSavepointUndo(pPager->pWal, pSavepoint->aWalData);
    }
    for(ii=pSavepoint->iSubRec; rc==SQLITE_OK && ii<pPager->nSubRec; ii++){
      assert( offset==(i64)ii*(4+pPager->pageSize) );
      rc = pager_playback_one_page(pPager, &offset, pDone, 0, 1);
    }
    assert( rc!=SQLITE_DONE );
  }

  sqlite3BitvecDestroy(pDone);
  if( rc==SQLITE_OK ){
    pPager->journalOff = szJ;
  }

  return rc;
}

/*
** Change the maximum number of in-memory pages that are allowed.
*/
SQLITE_PRIVATE void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
  sqlite3PcacheSetCachesize(pPager->pPCache, mxPage);
}

/*
** Free as much memory as possible from the pager.
*/
SQLITE_PRIVATE void sqlite3PagerShrink(Pager *pPager){
  sqlite3PcacheShrink(pPager->pPCache);
}

/*
** Adjust the robustness of the database to damage due to OS crashes
** or power failures by changing the number of syncs()s when writing
** the rollback journal.  There are three levels:
**
**    OFF       sqlite3OsSync() is never called.  This is the default

  }else if( bCkptFullFsync ){
    pPager->syncFlags = SQLITE_SYNC_NORMAL;
    pPager->ckptSyncFlags = SQLITE_SYNC_FULL;
  }else{
    pPager->syncFlags = SQLITE_SYNC_NORMAL;
    pPager->ckptSyncFlags = SQLITE_SYNC_NORMAL;
  }
  pPager->walSyncFlags = pPager->syncFlags;
  if( pPager->fullSync ){
    pPager->walSyncFlags |= WAL_SYNC_TRANSACTIONS;
  }
}
#endif

/*
** The following global variable is incremented whenever the library
** attempts to open a temporary file.  This information is used for
** testing and analysis only.  

    if( rc==SQLITE_OK ){
      pNew = (char *)sqlite3PageMalloc(pageSize);
      if( !pNew ) rc = SQLITE_NOMEM;
    }

    if( rc==SQLITE_OK ){
      pager_reset(pPager);
      pPager->dbSize = (Pgno)((nByte+pageSize-1)/pageSize);
      pPager->pageSize = pageSize;
      sqlite3PageFree(pPager->pTmpSpace);
      pPager->pTmpSpace = pNew;
      sqlite3PcacheSetPageSize(pPager->pPCache, pageSize);
    }
  }

  /* Before the first write, give the VFS a hint of what the final
  ** file size will be.
  */
  assert( rc!=SQLITE_OK || isOpen(pPager->fd) );
  if( rc==SQLITE_OK && pPager->dbSize>pPager->dbHintSize ){
    sqlite3_int64 szFile = pPager->pageSize * (sqlite3_int64)pPager->dbSize;
    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
    pPager->dbHintSize = pPager->dbSize;
  }

  while( rc==SQLITE_OK && pList ){
    Pgno pgno = pList->pgno;

    /* If there are dirty pages in the page cache with page numbers greater

    );
    rc = openSubJournal(pPager);

    /* If the sub-journal was opened successfully (or was already open),
    ** write the journal record into the file.  */
    if( rc==SQLITE_OK ){
      void *pData = pPg->pData;
      i64 offset = (i64)pPager->nSubRec*(4+pPager->pageSize);
      char *pData2;
  
      CODEC2(pPager, pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
      PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
      rc = write32bits(pPager->sjfd, offset, pPg->pgno);
      if( rc==SQLITE_OK ){
        rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);

  pPg->pDirty = 0;
  if( pagerUseWal(pPager) ){
    /* Write a single frame for this page to the log. */
    if( subjRequiresPage(pPg) ){ 
      rc = subjournalPage(pPg); 
    }
    if( rc==SQLITE_OK ){
      rc = pagerWalFrames(pPager, pPg, 0, 0);
    }
  }else{
  
    /* Sync the journal file if required. */
    if( pPg->flags&PGHDR_NEED_SYNC 
     || pPager->eState==PAGER_WRITER_CACHEMOD
    ){

    rc = sqlite3OsFullPathname(pVfs, zFilename, nPathname, zPathname);
    nPathname = sqlite3Strlen30(zPathname);
    z = zUri = &zFilename[sqlite3Strlen30(zFilename)+1];
    while( *z ){
      z += sqlite3Strlen30(z)+1;
      z += sqlite3Strlen30(z)+1;
    }
    nUri = (int)(&z[1] - zUri);
    assert( nUri>=0 );
    if( rc==SQLITE_OK && nPathname+8>pVfs->mxPathname ){
      /* This branch is taken when the journal path required by
      ** the database being opened will be more than pVfs->mxPathname
      ** bytes in length. This means the database cannot be opened,
      ** as it will not be possible to open the journal file or even
      ** check for a hot-journal before reading.
      */

  */
  pPtr = (u8 *)sqlite3MallocZero(
    ROUND8(sizeof(*pPager)) +      /* Pager structure */
    ROUND8(pcacheSize) +           /* PCache object */
    ROUND8(pVfs->szOsFile) +       /* The main db file */
    journalFileSize * 2 +          /* The two journal files */ 
    nPathname + 1 + nUri +         /* zFilename */
    nPathname + 8 + 2              /* zJournal */
#ifndef SQLITE_OMIT_WAL
    + nPathname + 4 + 2            /* zWal */
#endif
  );
  assert( EIGHT_BYTE_ALIGNMENT(SQLITE_INT_TO_PTR(journalFileSize)) );
  if( !pPtr ){
    sqlite3_free(zPathname);
    return SQLITE_NOMEM;
  }

  /* Fill in the Pager.zFilename and Pager.zJournal buffers, if required. */
  if( zPathname ){
    assert( nPathname>0 );
    pPager->zJournal =   (char*)(pPtr += nPathname + 1 + nUri);
    memcpy(pPager->zFilename, zPathname, nPathname);
    memcpy(&pPager->zFilename[nPathname+1], zUri, nUri);
    memcpy(pPager->zJournal, zPathname, nPathname);
    memcpy(&pPager->zJournal[nPathname], "-journal\000", 8+1);
    sqlite3FileSuffix3(pPager->zFilename, pPager->zJournal);
#ifndef SQLITE_OMIT_WAL
    pPager->zWal = &pPager->zJournal[nPathname+8+1];
    memcpy(pPager->zWal, zPathname, nPathname);
    memcpy(&pPager->zWal[nPathname], "-wal\000", 4+1);
    sqlite3FileSuffix3(pPager->zFilename, pPager->zWal);
#endif
    sqlite3_free(zPathname);
  }
  pPager->pVfs = pVfs;
  pPager->vfsFlags = vfsFlags;

  assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
  pPager->exclusiveMode = (u8)tempFile; 
  pPager->changeCountDone = pPager->tempFile;
  pPager->memDb = (u8)memDb;
  pPager->readOnly = (u8)readOnly;
  assert( useJournal || pPager->tempFile );
  pPager->noSync = pPager->tempFile;
  if( pPager->noSync ){
    assert( pPager->fullSync==0 );
    assert( pPager->syncFlags==0 );
    assert( pPager->walSyncFlags==0 );
    assert( pPager->ckptSyncFlags==0 );
  }else{
    pPager->fullSync = 1;
    pPager->syncFlags = SQLITE_SYNC_NORMAL;
    pPager->walSyncFlags = SQLITE_SYNC_NORMAL | WAL_SYNC_TRANSACTIONS;
    pPager->ckptSyncFlags = SQLITE_SYNC_NORMAL;
  }
  /* pPager->pFirst = 0; */
  /* pPager->pFirstSynced = 0; */
  /* pPager->pLast = 0; */
  pPager->nExtra = (u16)nExtra;
  pPager->journalSizeLimit = SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT;
  assert( isOpen(pPager->fd) || tempFile );
  setSectorSize(pPager);

SQLITE_PRIVATE int sqlite3PagerSync(Pager *pPager){
  int rc = SQLITE_OK;
  if( !pPager->noSync ){
    assert( !MEMDB );
    rc = sqlite3OsSync(pPager->fd, pPager->syncFlags);
  }else if( isOpen(pPager->fd) ){
    assert( !MEMDB );
    rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_SYNC_OMITTED, 0);
    if( rc==SQLITE_NOTFOUND ){
      rc = SQLITE_OK;
    }
  }
  return rc;
}

/*
** This function may only be called while a write-transaction is active in
** rollback. If the connection is in WAL mode, this call is a no-op. 

        ** Ticket [2d1a5c67dfc2363e44f29d9bbd57f] 2011-05-18 */
        rc = sqlite3PagerGet(pPager, 1, &pPageOne);
        pList = pPageOne;
        pList->pDirty = 0;
      }
      assert( rc==SQLITE_OK );
      if( ALWAYS(pList) ){
        rc = pagerWalFrames(pPager, pList, pPager->dbSize, 1);


      }
      sqlite3PagerUnref(pPageOne);
      if( rc==SQLITE_OK ){
        sqlite3PcacheCleanAll(pPager->pPCache);
      }
    }else{
      /* The following block updates the change-counter. Exactly how it

      return rc;
    }
  }else{
    rc = pager_playback(pPager, 0);
  }

  assert( pPager->eState==PAGER_READER || rc!=SQLITE_OK );
  assert( rc==SQLITE_OK || rc==SQLITE_FULL
          || rc==SQLITE_NOMEM || (rc&0xFF)==SQLITE_IOERR );

  /* If an error occurs during a ROLLBACK, we can no longer trust the pager
  ** cache. So call pager_error() on the way out to make any error persistent.
  */
  return pager_error(pPager, rc);
}

struct Wal {
  sqlite3_vfs *pVfs;         /* The VFS used to create pDbFd */
  sqlite3_file *pDbFd;       /* File handle for the database file */
  sqlite3_file *pWalFd;      /* File handle for WAL file */
  u32 iCallback;             /* Value to pass to log callback (or 0) */
  i64 mxWalSize;             /* Truncate WAL to this size upon reset */
  int nWiData;               /* Size of array apWiData */
  int szFirstBlock;          /* Size of first block written to WAL file */
  volatile u32 **apWiData;   /* Pointer to wal-index content in memory */
  u32 szPage;                /* Database page size */
  i16 readLock;              /* Which read lock is being held.  -1 for none */
  u8 syncFlags;              /* Flags to use to sync header writes */
  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
  u8 writeLock;              /* True if in a write transaction */
  u8 ckptLock;               /* True if holding a checkpoint lock */
  u8 readOnly;               /* WAL_RDWR, WAL_RDONLY, or WAL_SHM_RDONLY */
  u8 truncateOnCommit;       /* True to truncate WAL file on commit */
  u8 syncHeader;             /* Fsync the WAL header if true */
  u8 padToSectorBoundary;    /* Pad transactions out to the next sector */
  WalIndexHdr hdr;           /* Wal-index header for current transaction */
  const char *zWalName;      /* Name of WAL file */
  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
#ifdef SQLITE_DEBUG
  u8 lockError;              /* True if a locking error has occurred */
#endif
};

    int szFrame;                  /* Number of bytes in buffer aFrame[] */
    u8 *aData;                    /* Pointer to data part of aFrame buffer */
    int iFrame;                   /* Index of last frame read */
    i64 iOffset;                  /* Next offset to read from log file */
    int szPage;                   /* Page size according to the log */
    u32 magic;                    /* Magic value read from WAL header */
    u32 version;                  /* Magic value read from WAL header */
    int isValid;                  /* True if this frame is valid */

    /* Read in the WAL header. */
    rc = sqlite3OsRead(pWal->pWalFd, aBuf, WAL_HDRSIZE, 0);
    if( rc!=SQLITE_OK ){
      goto recovery_error;
    }

    aData = &aFrame[WAL_FRAME_HDRSIZE];

    /* Read all frames from the log file. */
    iFrame = 0;
    for(iOffset=WAL_HDRSIZE; (iOffset+szFrame)<=nSize; iOffset+=szFrame){
      u32 pgno;                   /* Database page number for frame */
      u32 nTruncate;              /* dbsize field from frame header */


      /* Read and decode the next log frame. */
      iFrame++;
      rc = sqlite3OsRead(pWal->pWalFd, aFrame, szFrame, iOffset);
      if( rc!=SQLITE_OK ) break;
      isValid = walDecodeFrame(pWal, &pgno, &nTruncate, aData, aFrame);
      if( !isValid ) break;
      rc = walIndexAppend(pWal, iFrame, pgno);
      if( rc!=SQLITE_OK ) break;

      /* If nTruncate is non-zero, this is a commit record. */
      if( nTruncate ){
        pWal->hdr.mxFrame = iFrame;
        pWal->hdr.nPage = nTruncate;
        pWal->hdr.szPage = (u16)((szPage&0xff00) | (szPage>>16));

  pRet->pVfs = pVfs;
  pRet->pWalFd = (sqlite3_file *)&pRet[1];
  pRet->pDbFd = pDbFd;
  pRet->readLock = -1;
  pRet->mxWalSize = mxWalSize;
  pRet->zWalName = zWalName;
  pRet->syncHeader = 1;
  pRet->padToSectorBoundary = 1;
  pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);

  /* Open file handle on the write-ahead log file. */
  flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
  rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
  if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){
    pRet->readOnly = WAL_RDONLY;
  }

  if( rc!=SQLITE_OK ){
    walIndexClose(pRet, 0);
    sqlite3OsClose(pRet->pWalFd);
    sqlite3_free(pRet);
  }else{
    int iDC = sqlite3OsDeviceCharacteristics(pRet->pWalFd);
    if( iDC & SQLITE_IOCAP_SEQUENTIAL ){ pRet->syncHeader = 0; }
    if( iDC & SQLITE_IOCAP_POWERSAFE_OVERWRITE ){
      pRet->padToSectorBoundary = 0;
    }
    *ppWal = pRet;
    WALTRACE(("WAL%d: opened\n", pRet));
  }
  return rc;
}

/*

    /* If the database file may grow as a result of this checkpoint, hint
    ** about the eventual size of the db file to the VFS layer. 
    */
    if( rc==SQLITE_OK ){
      i64 nReq = ((i64)mxPage * szPage);
      rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
      if( rc==SQLITE_OK && nSize<nReq ){
        sqlite3OsFileControlHint(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT, &nReq);
      }
    }

    /* Iterate through the contents of the WAL, copying data to the db file. */
    while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
      i64 iOffset;
      assert( walFramePgno(pWal, iFrame)==iDbpage );

    }
  }

 walcheckpoint_out:
  walIteratorFree(pIter);
  return rc;
}

/*
** If the WAL file is currently larger than nMax bytes in size, truncate
** it to exactly nMax bytes. If an error occurs while doing so, ignore it.
*/
static void walLimitSize(Wal *pWal, i64 nMax){
  i64 sz;
  int rx;
  sqlite3BeginBenignMalloc();
  rx = sqlite3OsFileSize(pWal->pWalFd, &sz);
  if( rx==SQLITE_OK && (sz > nMax ) ){
    rx = sqlite3OsTruncate(pWal->pWalFd, nMax);
  }
  sqlite3EndBenignMalloc();
  if( rx ){
    sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);
  }
}

/*
** Close a connection to a log file.
*/
SQLITE_PRIVATE int sqlite3WalClose(
  Wal *pWal,                      /* Wal to close */
  int sync_flags,                 /* Flags to pass to OsSync() (or 0) */

    ** the database. In this case checkpoint the database and unlink both
    ** the wal and wal-index files.
    **
    ** The EXCLUSIVE lock is not released before returning.
    */
    rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE);
    if( rc==SQLITE_OK ){

      if( pWal->exclusiveMode==WAL_NORMAL_MODE ){
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }
      rc = sqlite3WalCheckpoint(
          pWal, SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
      );
      if( rc==SQLITE_OK ){
        int bPersist = -1;
        sqlite3OsFileControlHint(
            pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
        );
        if( bPersist!=1 ){
          /* Try to delete the WAL file if the checkpoint completed and
          ** fsyned (rc==SQLITE_OK) and if we are not in persistent-wal
          ** mode (!bPersist) */
          isDelete = 1;
        }else if( pWal->mxWalSize>=0 ){
          /* Try to truncate the WAL file to zero bytes if the checkpoint
          ** completed and fsynced (rc==SQLITE_OK) and we are in persistent
          ** WAL mode (bPersist) and if the PRAGMA journal_size_limit is a
          ** non-negative value (pWal->mxWalSize>=0).  Note that we truncate
          ** to zero bytes as truncating to the journal_size_limit might
          ** leave a corrupt WAL file on disk. */
          walLimitSize(pWal, 0);
        }
      }
    }

    walIndexClose(pWal, isDelete);
    sqlite3OsClose(pWal->pWalFd);
    if( isDelete ){
      sqlite3BeginBenignMalloc();
      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);
      sqlite3EndBenignMalloc();
    }
    WALTRACE(("WAL%p: closed\n", pWal));
    sqlite3_free((void *)pWal->apWiData);
    sqlite3_free(pWal);
  }
  return rc;
}