#ifndef SQLITE_DISABLE_LFS
# define _LARGE_FILE       1
# ifndef _FILE_OFFSET_BITS
#   define _FILE_OFFSET_BITS 64
# endif
# define _LARGEFILE_SOURCE 1
#endif








/* Needed for various definitions... */
#if defined(__GNUC__) && !defined(_GNU_SOURCE)
# define _GNU_SOURCE
#endif

#if defined(__OpenBSD__) && !defined(_BSD_SOURCE)
................................................................................
**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.8.11"
#define SQLITE_VERSION_NUMBER 3008011
#define SQLITE_SOURCE_ID      "2015-06-26 02:41:31 015302f15e46a087ec92f3644c6741600dbf4306"

/*
** 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
................................................................................
#  define SQLITE_NOINLINE  __attribute__((noinline))
#elif defined(_MSC_VER) && _MSC_VER>=1310
#  define SQLITE_NOINLINE  __declspec(noinline)
#else
#  define SQLITE_NOINLINE
#endif











/*
** The SQLITE_THREADSAFE macro must be defined as 0, 1, or 2.
** 0 means mutexes are permanently disable and the library is never
** threadsafe.  1 means the library is serialized which is the highest
** level of threadsafety.  2 means the library is multithreaded - multiple
** threads can use SQLite as long as no two threads try to use the same
** database connection at the same time.
................................................................................
  u8 opcode;          /* What operation to perform */
  signed char p4type; /* One of the P4_xxx constants for p4 */
  u8 opflags;         /* Mask of the OPFLG_* flags in opcodes.h */
  u8 p5;              /* Fifth parameter is an unsigned character */
  int p1;             /* First operand */
  int p2;             /* Second parameter (often the jump destination) */
  int p3;             /* The third parameter */
  union {             /* fourth parameter */
    int i;                 /* Integer value if p4type==P4_INT32 */
    void *p;               /* Generic pointer */
    char *z;               /* Pointer to data for string (char array) types */
    i64 *pI64;             /* Used when p4type is P4_INT64 */
    double *pReal;         /* Used when p4type is P4_REAL */
    FuncDef *pFunc;        /* Used when p4type is P4_FUNCDEF */

    CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
    Mem *pMem;             /* Used when p4type is P4_MEM */
    VTable *pVtab;         /* Used when p4type is P4_VTAB */
    KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
    int *ai;               /* Used when p4type is P4_INTARRAY */
    SubProgram *pProgram;  /* Used when p4type is P4_SUBPROGRAM */
    int (*xAdvance)(BtCursor *, int *);
................................................................................
#define P4_MPRINTF  (-11) /* P4 is a string obtained from sqlite3_mprintf() */
#define P4_REAL     (-12) /* P4 is a 64-bit floating point value */
#define P4_INT64    (-13) /* P4 is a 64-bit signed integer */
#define P4_INT32    (-14) /* P4 is a 32-bit signed integer */
#define P4_INTARRAY (-15) /* P4 is a vector of 32-bit integers */
#define P4_SUBPROGRAM  (-18) /* P4 is a pointer to a SubProgram structure */
#define P4_ADVANCE  (-19) /* P4 is a pointer to BtreeNext() or BtreePrev() */


/* Error message codes for OP_Halt */
#define P5_ConstraintNotNull 1
#define P5_ConstraintUnique  2
#define P5_ConstraintCheck   3
#define P5_ConstraintFK      4

................................................................................
** The makefile scans the vdbe.c source file and creates the "opcodes.h"
** header file that defines a number for each opcode used by the VDBE.
*/
/************** Include opcodes.h in the middle of vdbe.h ********************/
/************** Begin file opcodes.h *****************************************/
/* Automatically generated.  Do not edit */
/* See the mkopcodeh.awk script for details */
#define OP_Function        1 /* synopsis: r[P3]=func(r[P2@P5])             */
#define OP_Savepoint       2
#define OP_AutoCommit      3
#define OP_Transaction     4
#define OP_SorterNext      5
#define OP_PrevIfOpen      6
#define OP_NextIfOpen      7
#define OP_Prev            8
#define OP_Next            9
#define OP_AggStep        10 /* synopsis: accum=r[P3] step(r[P2@P5])       */
#define OP_Checkpoint     11
#define OP_JournalMode    12
#define OP_Vacuum         13
#define OP_VFilter        14 /* synopsis: iplan=r[P3] zplan='P4'           */
#define OP_VUpdate        15 /* synopsis: data=r[P3@P2]                    */
#define OP_Goto           16
#define OP_Gosub          17
#define OP_Return         18
#define OP_Not            19 /* same as TK_NOT, synopsis: r[P2]= !r[P1]    */
#define OP_InitCoroutine  20
#define OP_EndCoroutine   21

#define OP_Yield          22
#define OP_HaltIfNull     23 /* synopsis: if r[P3]=null halt               */
#define OP_Halt           24
#define OP_Integer        25 /* synopsis: r[P2]=P1                         */
#define OP_Int64          26 /* synopsis: r[P2]=P4                         */
#define OP_String         27 /* synopsis: r[P2]='P4' (len=P1)              */
#define OP_Null           28 /* synopsis: r[P2..P3]=NULL                   */
#define OP_SoftNull       29 /* synopsis: r[P1]=NULL                       */
#define OP_Blob           30 /* synopsis: r[P2]=P4 (len=P1)                */
#define OP_Variable       31 /* synopsis: r[P2]=parameter(P1,P4)           */
#define OP_Move           32 /* synopsis: r[P2@P3]=r[P1@P3]                */
#define OP_Copy           33 /* synopsis: r[P2@P3+1]=r[P1@P3+1]            */
#define OP_SCopy          34 /* synopsis: r[P2]=r[P1]                      */
#define OP_ResultRow      35 /* synopsis: output=r[P1@P2]                  */
#define OP_CollSeq        36


#define OP_AddImm         37 /* synopsis: r[P1]=r[P1]+P2                   */
#define OP_MustBeInt      38
#define OP_RealAffinity   39
#define OP_Cast           40 /* synopsis: affinity(r[P1])                  */
#define OP_Permutation    41
#define OP_Compare        42 /* synopsis: r[P1@P3] <-> r[P2@P3]            */
#define OP_Jump           43
................................................................................
#define OP_FkIfZero      136 /* synopsis: if fkctr[P1]==0 goto P2          */
#define OP_MemMax        137 /* synopsis: r[P1]=max(r[P1],r[P2])           */
#define OP_IfPos         138 /* synopsis: if r[P1]>0 goto P2               */
#define OP_IfNeg         139 /* synopsis: r[P1]+=P3, if r[P1]<0 goto P2    */
#define OP_IfNotZero     140 /* synopsis: if r[P1]!=0 then r[P1]+=P3, goto P2 */
#define OP_DecrJumpZero  141 /* synopsis: if (--r[P1])==0 goto P2          */
#define OP_JumpZeroIncr  142 /* synopsis: if (r[P1]++)==0 ) goto P2        */


#define OP_AggFinal      143 /* synopsis: accum=r[P1] N=P2                 */
#define OP_IncrVacuum    144
#define OP_Expire        145
#define OP_TableLock     146 /* synopsis: iDb=P1 root=P2 write=P3          */
#define OP_VBegin        147
#define OP_VCreate       148
#define OP_VDestroy      149
#define OP_VOpen         150
#define OP_VColumn       151 /* synopsis: r[P3]=vcolumn(P2)                */
#define OP_VNext         152
#define OP_VRename       153
#define OP_Pagecount     154
#define OP_MaxPgcnt      155
#define OP_Init          156 /* synopsis: Start at P2                      */
#define OP_Noop          157
#define OP_Explain       158


/* Properties such as "out2" or "jump" that are specified in
** comments following the "case" for each opcode in the vdbe.c
** are encoded into bitvectors as follows:
*/
#define OPFLG_JUMP            0x0001  /* jump:  P2 holds jmp target */
#define OPFLG_IN1             0x0002  /* in1:   P1 is an input */
#define OPFLG_IN2             0x0004  /* in2:   P2 is an input */
#define OPFLG_IN3             0x0008  /* in3:   P3 is an input */
#define OPFLG_OUT2            0x0010  /* out2:  P2 is an output */
#define OPFLG_OUT3            0x0020  /* out3:  P3 is an output */
#define OPFLG_INITIALIZER {\
/*   0 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01,\
/*   8 */ 0x01, 0x01, 0x00, 0x00, 0x10, 0x00, 0x01, 0x00,\
/*  16 */ 0x01, 0x01, 0x02, 0x12, 0x01, 0x02, 0x03, 0x08,\
/*  24 */ 0x00, 0x10, 0x10, 0x10, 0x10, 0x00, 0x10, 0x10,\
/*  32 */ 0x00, 0x00, 0x10, 0x00, 0x00, 0x02, 0x03, 0x02,\
/*  40 */ 0x02, 0x00, 0x00, 0x01, 0x01, 0x03, 0x03, 0x00,\
/*  48 */ 0x00, 0x00, 0x10, 0x10, 0x08, 0x00, 0x00, 0x00,\
/*  56 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x09,\
/*  64 */ 0x09, 0x09, 0x09, 0x04, 0x09, 0x09, 0x09, 0x26,\
/*  72 */ 0x26, 0x09, 0x10, 0x10, 0x03, 0x03, 0x0b, 0x0b,\
/*  80 */ 0x0b, 0x0b, 0x0b, 0x0b, 0x00, 0x26, 0x26, 0x26,\
/*  88 */ 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x00,\
/*  96 */ 0x12, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
/* 104 */ 0x10, 0x00, 0x01, 0x01, 0x01, 0x01, 0x04, 0x04,\
/* 112 */ 0x00, 0x10, 0x01, 0x01, 0x01, 0x01, 0x10, 0x00,\
/* 120 */ 0x00, 0x10, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00,\
/* 128 */ 0x00, 0x06, 0x23, 0x0b, 0x01, 0x10, 0x10, 0x00,\
/* 136 */ 0x01, 0x04, 0x03, 0x03, 0x03, 0x03, 0x03, 0x00,\
/* 144 */ 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
/* 152 */ 0x01, 0x00, 0x10, 0x10, 0x01, 0x00, 0x00,}


/************** End of opcodes.h *********************************************/
/************** Continuing where we left off in vdbe.h ***********************/

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.
................................................................................
  PCache *pCache;                /* Cache that owns this page */

  PgHdr *pDirtyNext;             /* Next element in list of dirty pages */
  PgHdr *pDirtyPrev;             /* Previous element in list of dirty pages */
};

/* Bit values for PgHdr.flags */

#define PGHDR_DIRTY             0x002  /* Page has changed */

#define PGHDR_NEED_SYNC         0x004  /* Fsync the rollback journal before
                                       ** writing this page to the database */
#define PGHDR_NEED_READ         0x008  /* Content is unread */
#define PGHDR_REUSE_UNLIKELY    0x010  /* A hint that reuse is unlikely */
#define PGHDR_DONT_WRITE        0x020  /* Do not write content to disk */

#define PGHDR_MMAP              0x040  /* This is an mmap page object */

/* Initialize and shutdown the page cache subsystem */
SQLITE_PRIVATE int sqlite3PcacheInitialize(void);
SQLITE_PRIVATE void sqlite3PcacheShutdown(void);

/* Page cache buffer management:
** These routines implement SQLITE_CONFIG_PAGECACHE.
................................................................................
# define sqlite3FaultSim(X) SQLITE_OK
#else
SQLITE_PRIVATE   int sqlite3FaultSim(int);
#endif

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*);
#ifndef SQLITE_OMIT_BUILTIN_TEST
SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int,int*);
#endif
................................................................................
** But this file is the only place where the internal details of this
** structure are known.
**
** This structure is defined inside of vdbeInt.h because it uses substructures
** (Mem) which are only defined there.
*/
struct sqlite3_context {
  Mem *pOut;            /* The return value is stored here */
  FuncDef *pFunc;       /* Pointer to function information */
  Mem *pMem;            /* Memory cell used to store aggregate context */
  Vdbe *pVdbe;          /* The VM that owns this context */
  int iOp;              /* Instruction number of OP_Function */
  int isError;          /* Error code returned by the function. */
  u8 skipFlag;          /* Skip accumulator loading if true */
  u8 fErrorOrAux;       /* isError!=0 or pVdbe->pAuxData modified */


};

/*
** An Explain object accumulates indented output which is helpful
** in describing recursive data structures.
*/
struct Explain {
................................................................................
** returning control to the user) that has called sqlite3_malloc or
** sqlite3_realloc.
**
** The returned value is normally a copy of the second argument to this
** function. However, if a malloc() failure has occurred since the previous
** invocation SQLITE_NOMEM is returned instead. 
**
** If the first argument, db, is not NULL and a malloc() error has occurred,
** then the connection error-code (the value returned by sqlite3_errcode())
** is set to SQLITE_NOMEM.
*/
SQLITE_PRIVATE int sqlite3ApiExit(sqlite3* db, int rc){
  /* If the db handle is not NULL, then we must hold the connection handle
  ** mutex here. Otherwise the read (and possible write) of db->mallocFailed 
  ** is unsafe, as is the call to sqlite3Error().
  */

  assert( !db || sqlite3_mutex_held(db->mutex) );
  if( db==0 ) return rc & 0xff;
  if( db->mallocFailed || rc==SQLITE_IOERR_NOMEM ){
    return apiOomError(db);
  }
  return rc & db->errMask;
}

/************** End of malloc.c **********************************************/
................................................................................
** lower 30 bits of a 32-bit signed integer.
**
** The value returned will never be negative.  Nor will it ever be greater
** than the actual length of the string.  For very long strings (greater
** than 1GiB) the value returned might be less than the true string length.
*/
SQLITE_PRIVATE int sqlite3Strlen30(const char *z){
  const char *z2 = z;
  if( z==0 ) return 0;
  while( *z2 ){ z2++; }
  return 0x3fffffff & (int)(z2 - z);
}

/*
** Set the current error code to err_code and clear any prior error message.
*/
SQLITE_PRIVATE void sqlite3Error(sqlite3 *db, int err_code){
  assert( db!=0 );
................................................................................
}


/*
** Read or write a four-byte big-endian integer value.
*/
SQLITE_PRIVATE u32 sqlite3Get4byte(const u8 *p){













  testcase( p[0]&0x80 );
  return ((unsigned)p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];

}
SQLITE_PRIVATE void sqlite3Put4byte(unsigned char *p, u32 v){









  p[0] = (u8)(v>>24);
  p[1] = (u8)(v>>16);
  p[2] = (u8)(v>>8);
  p[3] = (u8)v;

}



/*
** Translate a single byte of Hex into an integer.
** This routine only works if h really is a valid hexadecimal
................................................................................
#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS) || defined(SQLITE_DEBUG)
# define OpHelp(X) "\0" X
#else
# define OpHelp(X)
#endif
SQLITE_PRIVATE const char *sqlite3OpcodeName(int i){
 static const char *const azName[] = { "?",
     /*   1 */ "Function"         OpHelp("r[P3]=func(r[P2@P5])"),
     /*   2 */ "Savepoint"        OpHelp(""),
     /*   3 */ "AutoCommit"       OpHelp(""),
     /*   4 */ "Transaction"      OpHelp(""),
     /*   5 */ "SorterNext"       OpHelp(""),
     /*   6 */ "PrevIfOpen"       OpHelp(""),
     /*   7 */ "NextIfOpen"       OpHelp(""),
     /*   8 */ "Prev"             OpHelp(""),
     /*   9 */ "Next"             OpHelp(""),
     /*  10 */ "AggStep"          OpHelp("accum=r[P3] step(r[P2@P5])"),
     /*  11 */ "Checkpoint"       OpHelp(""),
     /*  12 */ "JournalMode"      OpHelp(""),
     /*  13 */ "Vacuum"           OpHelp(""),
     /*  14 */ "VFilter"          OpHelp("iplan=r[P3] zplan='P4'"),
     /*  15 */ "VUpdate"          OpHelp("data=r[P3@P2]"),
     /*  16 */ "Goto"             OpHelp(""),
     /*  17 */ "Gosub"            OpHelp(""),
     /*  18 */ "Return"           OpHelp(""),
     /*  19 */ "Not"              OpHelp("r[P2]= !r[P1]"),
     /*  20 */ "InitCoroutine"    OpHelp(""),
     /*  21 */ "EndCoroutine"     OpHelp(""),

     /*  22 */ "Yield"            OpHelp(""),
     /*  23 */ "HaltIfNull"       OpHelp("if r[P3]=null halt"),
     /*  24 */ "Halt"             OpHelp(""),
     /*  25 */ "Integer"          OpHelp("r[P2]=P1"),
     /*  26 */ "Int64"            OpHelp("r[P2]=P4"),
     /*  27 */ "String"           OpHelp("r[P2]='P4' (len=P1)"),
     /*  28 */ "Null"             OpHelp("r[P2..P3]=NULL"),
     /*  29 */ "SoftNull"         OpHelp("r[P1]=NULL"),
     /*  30 */ "Blob"             OpHelp("r[P2]=P4 (len=P1)"),
     /*  31 */ "Variable"         OpHelp("r[P2]=parameter(P1,P4)"),
     /*  32 */ "Move"             OpHelp("r[P2@P3]=r[P1@P3]"),
     /*  33 */ "Copy"             OpHelp("r[P2@P3+1]=r[P1@P3+1]"),
     /*  34 */ "SCopy"            OpHelp("r[P2]=r[P1]"),
     /*  35 */ "ResultRow"        OpHelp("output=r[P1@P2]"),
     /*  36 */ "CollSeq"          OpHelp(""),


     /*  37 */ "AddImm"           OpHelp("r[P1]=r[P1]+P2"),
     /*  38 */ "MustBeInt"        OpHelp(""),
     /*  39 */ "RealAffinity"     OpHelp(""),
     /*  40 */ "Cast"             OpHelp("affinity(r[P1])"),
     /*  41 */ "Permutation"      OpHelp(""),
     /*  42 */ "Compare"          OpHelp("r[P1@P3] <-> r[P2@P3]"),
     /*  43 */ "Jump"             OpHelp(""),
................................................................................
     /* 136 */ "FkIfZero"         OpHelp("if fkctr[P1]==0 goto P2"),
     /* 137 */ "MemMax"           OpHelp("r[P1]=max(r[P1],r[P2])"),
     /* 138 */ "IfPos"            OpHelp("if r[P1]>0 goto P2"),
     /* 139 */ "IfNeg"            OpHelp("r[P1]+=P3, if r[P1]<0 goto P2"),
     /* 140 */ "IfNotZero"        OpHelp("if r[P1]!=0 then r[P1]+=P3, goto P2"),
     /* 141 */ "DecrJumpZero"     OpHelp("if (--r[P1])==0 goto P2"),
     /* 142 */ "JumpZeroIncr"     OpHelp("if (r[P1]++)==0 ) goto P2"),


     /* 143 */ "AggFinal"         OpHelp("accum=r[P1] N=P2"),
     /* 144 */ "IncrVacuum"       OpHelp(""),
     /* 145 */ "Expire"           OpHelp(""),
     /* 146 */ "TableLock"        OpHelp("iDb=P1 root=P2 write=P3"),
     /* 147 */ "VBegin"           OpHelp(""),
     /* 148 */ "VCreate"          OpHelp(""),
     /* 149 */ "VDestroy"         OpHelp(""),
     /* 150 */ "VOpen"            OpHelp(""),
     /* 151 */ "VColumn"          OpHelp("r[P3]=vcolumn(P2)"),
     /* 152 */ "VNext"            OpHelp(""),
     /* 153 */ "VRename"          OpHelp(""),
     /* 154 */ "Pagecount"        OpHelp(""),
     /* 155 */ "MaxPgcnt"         OpHelp(""),
     /* 156 */ "Init"             OpHelp("Start at P2"),
     /* 157 */ "Noop"             OpHelp(""),
     /* 158 */ "Explain"          OpHelp(""),
  };
  return azName[i];
}
#endif

/************** End of opcodes.c *********************************************/
/************** Begin file os_unix.c *****************************************/
................................................................................
}

/*
** Check to see if the i-th bit is set.  Return true or false.
** If p is NULL (if the bitmap has not been created) or if
** i is out of range, then return false.
*/
SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec *p, u32 i){
  if( p==0 ) return 0;
  if( i>p->iSize || i==0 ) return 0;
  i--;

  while( p->iDivisor ){
    u32 bin = i/p->iDivisor;
    i = i%p->iDivisor;
    p = p->u.apSub[bin];
    if (!p) {
      return 0;
    }
................................................................................
    u32 h = BITVEC_HASH(i++);
    while( p->u.aHash[h] ){
      if( p->u.aHash[h]==i ) return 1;
      h = (h+1) % BITVEC_NINT;
    }
    return 0;
  }



}

/*
** Set the i-th bit.  Return 0 on success and an error code if
** anything goes wrong.
**
** This routine might cause sub-bitmaps to be allocated.  Failing
................................................................................
  Pgno pgno,                  /* Page number obtained */
  sqlite3_pcache_page *pPage  /* Page obtained by prior PcacheFetch() call */
){
  PgHdr *pPgHdr;
  assert( pPage!=0 );
  pPgHdr = (PgHdr*)pPage->pExtra;
  assert( pPgHdr->pPage==0 );
 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;

  return sqlite3PcacheFetchFinish(pCache,pgno,pPage);
}

/*
** This routine converts the sqlite3_pcache_page object returned by
** sqlite3PcacheFetch() into an initialized PgHdr object.  This routine
** must be called after sqlite3PcacheFetch() in order to get a usable
................................................................................
SQLITE_PRIVATE PgHdr *sqlite3PcacheFetchFinish(
  PCache *pCache,             /* Obtain the page from this cache */
  Pgno pgno,                  /* Page number obtained */
  sqlite3_pcache_page *pPage  /* Page obtained by prior PcacheFetch() call */
){
  PgHdr *pPgHdr;

  if( pPage==0 ) return 0;
  pPgHdr = (PgHdr *)pPage->pExtra;

  if( !pPgHdr->pPage ){
    return pcacheFetchFinishWithInit(pCache, pgno, pPage);
  }
  if( 0==pPgHdr->nRef ){
    pCache->nRef++;
................................................................................
** reference count drops to 0, then it is made eligible for recycling.
*/
SQLITE_PRIVATE void SQLITE_NOINLINE sqlite3PcacheRelease(PgHdr *p){
  assert( p->nRef>0 );
  p->nRef--;
  if( p->nRef==0 ){
    p->pCache->nRef--;
    if( (p->flags&PGHDR_DIRTY)==0 ){
      pcacheUnpin(p);
    }else if( p->pDirtyPrev!=0 ){
      /* Move the page to the head of the dirty list. */
      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
    }
  }
}
................................................................................
}

/*
** Make sure the page is marked as dirty. If it isn't dirty already,
** make it so.
*/
SQLITE_PRIVATE void sqlite3PcacheMakeDirty(PgHdr *p){
  p->flags &= ~PGHDR_DONT_WRITE;
  assert( p->nRef>0 );

  if( 0==(p->flags & PGHDR_DIRTY) ){
    p->flags |= PGHDR_DIRTY;


    pcacheManageDirtyList(p, PCACHE_DIRTYLIST_ADD);

  }
}

/*
** Make sure the page is marked as clean. If it isn't clean already,
** make it so.
*/
SQLITE_PRIVATE void sqlite3PcacheMakeClean(PgHdr *p){
  if( (p->flags & PGHDR_DIRTY) ){

    pcacheManageDirtyList(p, PCACHE_DIRTYLIST_REMOVE);
    p->flags &= ~(PGHDR_DIRTY|PGHDR_NEED_SYNC);

    if( p->nRef==0 ){
      pcacheUnpin(p);
    }
  }
}

/*
................................................................................
  return pPage;
}


/*
** Remove the page supplied as an argument from the hash table 
** (PCache1.apHash structure) that it is currently stored in.

**
** The PGroup mutex must be held when this function is called.
*/
static void pcache1RemoveFromHash(PgHdr1 *pPage){
  unsigned int h;
  PCache1 *pCache = pPage->pCache;
  PgHdr1 **pp;

  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
  h = pPage->iKey % pCache->nHash;
  for(pp=&pCache->apHash[h]; (*pp)!=pPage; pp=&(*pp)->pNext);
  *pp = (*pp)->pNext;

  pCache->nPage--;

}

/*
** If there are currently more than nMaxPage pages allocated, try
** to recycle pages to reduce the number allocated to nMaxPage.
*/
static void pcache1EnforceMaxPage(PGroup *pGroup){
  assert( sqlite3_mutex_held(pGroup->mutex) );
  while( pGroup->nCurrentPage>pGroup->nMaxPage && pGroup->pLruTail ){
    PgHdr1 *p = pGroup->pLruTail;
    assert( p->pCache->pGroup==pGroup );
    assert( p->isPinned==0 );
    pcache1PinPage(p);
    pcache1RemoveFromHash(p);
    pcache1FreePage(p);
  }
}

/*
** Discard all pages from cache pCache with a page number (key value) 
** greater than or equal to iLimit. Any pinned pages that meet this 
** criteria are unpinned before they are discarded.
................................................................................
         (pCache->nPage+1>=pCache->nMax)
      || pGroup->nCurrentPage>=pGroup->nMaxPage
      || pcache1UnderMemoryPressure(pCache)
  )){
    PCache1 *pOther;
    pPage = pGroup->pLruTail;
    assert( pPage->isPinned==0 );
    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 );
................................................................................
  ** part of the PGroup LRU list.
  */
  assert( pPage->pLruPrev==0 && pPage->pLruNext==0 );
  assert( pGroup->pLruHead!=pPage && pGroup->pLruTail!=pPage );
  assert( pPage->isPinned==1 );

  if( reuseUnlikely || pGroup->nCurrentPage>pGroup->nMaxPage ){
    pcache1RemoveFromHash(pPage);
    pcache1FreePage(pPage);
  }else{
    /* Add the page to the PGroup LRU list. */
    if( pGroup->pLruHead ){
      pGroup->pLruHead->pLruPrev = pPage;
      pPage->pLruNext = pGroup->pLruHead;
      pGroup->pLruHead = pPage;
    }else{
................................................................................
    while( (nReq<0 || nFree<nReq) && ((p=pcache1.grp.pLruTail)!=0) ){
      nFree += pcache1MemSize(p->page.pBuf);
#ifdef SQLITE_PCACHE_SEPARATE_HEADER
      nFree += sqlite3MemSize(p);
#endif
      assert( p->isPinned==0 );
      pcache1PinPage(p);
      pcache1RemoveFromHash(p);
      pcache1FreePage(p);
    }
    pcache1LeaveMutex(&pcache1.grp);
  }
  return nFree;
}
#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */

................................................................................
  u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */
#endif
};

/*
** Bits of the Pager.doNotSpill flag.  See further description below.
*/
#define SPILLFLAG_OFF         0x01      /* Never spill cache.  Set via pragma */
#define SPILLFLAG_ROLLBACK    0x02      /* Current rolling back, so do not spill */
#define SPILLFLAG_NOSYNC      0x04      /* Spill is ok, but do not sync */

/*
** An open page cache is an instance of struct Pager. A description of
** some of the more important member variables follows:
**
** eState
**
................................................................................
**   writing to the database from pagerStress() is disabled altogether.
**   The SPILLFLAG_ROLLBACK case is done in a very obscure case that
**   comes up during savepoint rollback that requires the pcache module
**   to allocate a new page to prevent the journal file from being written
**   while it is being traversed by code in pager_playback().  The SPILLFLAG_OFF
**   case is a user preference.
** 
**   If the SPILLFLAG_NOSYNC bit is set, writing to the database from pagerStress()
**   is permitted, but syncing the journal file is not. This flag is set
**   by sqlite3PagerWrite() when the file-system sector-size is larger than
**   the database page-size in order to prevent a journal sync from happening 
**   in between the journalling of two pages on the same sector. 
**
** subjInMemory
**
**   This is a boolean variable. If true, then any required sub-journal
**   is opened as an in-memory journal file. If false, then in-memory
**   sub-journals are only used for in-memory pager files.
**
................................................................................
  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
  u8 eLock;                   /* Current lock held on database file */
  u8 changeCountDone;         /* Set after incrementing the change-counter */
  u8 setMaster;               /* True if a m-j name has been written to jrnl */
  u8 doNotSpill;              /* Do not spill the cache when non-zero */
  u8 subjInMemory;            /* True to use in-memory sub-journals */
  u8 bUseFetch;               /* True to use xFetch() */
  u8 hasBeenUsed;             /* True if any content previously read from this pager*/
  Pgno dbSize;                /* Number of pages in the database */
  Pgno dbOrigSize;            /* dbSize before the current transaction */
  Pgno dbFileSize;            /* Number of pages in the database file */
  Pgno dbHintSize;            /* Value passed to FCNTL_SIZE_HINT call */
  int errCode;                /* One of several kinds of errors */
  int nRec;                   /* Pages journalled since last j-header written */
  u32 cksumInit;              /* Quasi-random value added to every checksum */
................................................................................
**
**   if( isOpen(pPager->jfd) ){ ...
**
** instead of
**
**   if( pPager->jfd->pMethods ){ ...
*/
#define isOpen(pFd) ((pFd)->pMethods)

/*
** Return true if this pager uses a write-ahead log instead of the usual
** rollback journal. Otherwise false.
*/
#ifndef SQLITE_OMIT_WAL
static int pagerUseWal(Pager *pPager){
................................................................................
static int subjRequiresPage(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  PagerSavepoint *p;
  Pgno pgno = pPg->pgno;
  int i;
  for(i=0; i<pPager->nSavepoint; i++){
    p = &pPager->aSavepoint[i];
    if( p->nOrig>=pgno && 0==sqlite3BitvecTest(p->pInSavepoint, pgno) ){
      return 1;
    }
  }
  return 0;
}


/*
** Return true if the page is already in the journal file.
*/
static int pageInJournal(Pager *pPager, PgHdr *pPg){
  return sqlite3BitvecTest(pPager->pInJournal, pPg->pgno);
}


/*
** Read a 32-bit integer from the given file descriptor.  Store the integer
** that is read in *pRes.  Return SQLITE_OK if everything worked, or an
** error code is something goes wrong.
**
** All values are stored on disk as big-endian.
................................................................................
  /* Write the master journal data to the end of the journal file. If
  ** an error occurs, return the error code to the caller.
  */
  if( (0 != (rc = write32bits(pPager->jfd, iHdrOff, PAGER_MJ_PGNO(pPager))))
   || (0 != (rc = sqlite3OsWrite(pPager->jfd, zMaster, nMaster, iHdrOff+4)))
   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nMaster, nMaster)))
   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nMaster+4, cksum)))
   || (0 != (rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, 8, iHdrOff+4+nMaster+8)))

  ){
    return rc;
  }
  pPager->journalOff += (nMaster+20);

  /* If the pager is in peristent-journal mode, then the physical 
  ** journal-file may extend past the end of the master-journal name
................................................................................
    rc = read32bits(jfd, (*pOffset)-4, &cksum);
    if( rc ) return rc;
    if( !isSavepnt && pager_cksum(pPager, (u8*)aData)!=cksum ){
      return SQLITE_DONE;
    }
  }

  /* If this page has already been played by before during the current
  ** rollback, then don't bother to play it back again.
  */
  if( pDone && (rc = sqlite3BitvecSet(pDone, pgno))!=SQLITE_OK ){
    return rc;
  }

  /* When playing back page 1, restore the nReserve setting
................................................................................
    }
  }
  return rc;
}

/*
** Append a record of the current state of page pPg to the sub-journal. 
** It is the callers responsibility to use subjRequiresPage() to check 
** that it is really required before calling this function.
**
** If successful, set the bit corresponding to pPg->pgno in the bitvecs
** for all open savepoints before returning.
**
** This function returns SQLITE_OK if everything is successful, an IO
** error code if the attempt to write to the sub-journal fails, or 
** SQLITE_NOMEM if a malloc fails while setting a bit in a savepoint
................................................................................
  }
  if( rc==SQLITE_OK ){
    pPager->nSubRec++;
    assert( pPager->nSavepoint>0 );
    rc = addToSavepointBitvecs(pPager, pPg->pgno);
  }
  return rc;







}

/*
** This function is called by the pcache layer when it has reached some
** soft memory limit. The first argument is a pointer to a Pager object
** (cast as a void*). The pager is always 'purgeable' (not an in-memory
** database). The second argument is a reference to a page that is 
................................................................................
  ){
    return SQLITE_OK;
  }

  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 = syncJournal(pPager, 1);
    }
  
    /* If the page number of this page is larger than the current size of
    ** the database image, it may need to be written to the sub-journal.
    ** This is because the call to pager_write_pagelist() below will not
    ** actually write data to the file in this case.
    **
    ** Consider the following sequence of events:
    **
    **   BEGIN;
    **     <journal page X>
    **     <modify page X>
    **     SAVEPOINT sp;
    **       <shrink database file to Y pages>
    **       pagerStress(page X)
    **     ROLLBACK TO sp;
    **
    ** If (X>Y), then when pagerStress is called page X will not be written
    ** out to the database file, but will be dropped from the cache. Then,
    ** following the "ROLLBACK TO sp" statement, reading page X will read
    ** data from the database file. This will be the copy of page X as it
    ** was when the transaction started, not as it was when "SAVEPOINT sp"
    ** was executed.
    **
    ** The solution is to write the current data for page X into the 
    ** sub-journal file now (if it is not already there), so that it will
    ** be restored to its current value when the "ROLLBACK TO sp" is 
    ** executed.
    */
    if( NEVER(
        rc==SQLITE_OK && pPg->pgno>pPager->dbSize && subjRequiresPage(pPg)
    ) ){
      rc = subjournalPage(pPg);
    }
  
    /* Write the contents of the page out to the database file. */
    if( rc==SQLITE_OK ){
      assert( (pPg->flags&PGHDR_NEED_SYNC)==0 );
      rc = pager_write_pagelist(pPager, pPg);
    }
  }

................................................................................
    ** disk and uses an in-memory rollback journal.
    **
    ** This branch also runs for files marked as immutable.
    */ 
act_like_temp_file:
    tempFile = 1;
    pPager->eState = PAGER_READER;     /* Pretend we already have a lock */
    pPager->eLock = EXCLUSIVE_LOCK;    /* Pretend we are in EXCLUSIVE locking mode */
    pPager->noLock = 1;                /* Do no locking */
    readOnly = (vfsFlags&SQLITE_OPEN_READONLY);
  }

  /* The following call to PagerSetPagesize() serves to set the value of 
  ** Pager.pageSize and to allocate the Pager.pTmpSpace buffer.
  */
................................................................................
  }

  /* Initialize the PCache object. */
  if( rc==SQLITE_OK ){
    assert( nExtra<1000 );
    nExtra = ROUND8(nExtra);
    rc = sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
                           !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);
  }

  /* If an error occurred above, free the  Pager structure and close the file.
  */
  if( rc!=SQLITE_OK ){
    sqlite3OsClose(pPager->fd);
    sqlite3PageFree(pPager->pTmpSpace);
................................................................................
    if( !pPager->tempFile && pPager->hasBeenUsed ){
      /* The shared-lock has just been acquired then check to
      ** see if the database has been modified.  If the database has changed,
      ** flush the cache.  The pPager->hasBeenUsed flag prevents this from
      ** occurring on the very first access to a file, in order to save a
      ** single unnecessary sqlite3OsRead() call at the start-up.
      **
      ** Database changes is detected by looking at 15 bytes beginning
      ** at offset 24 into the file.  The first 4 of these 16 bytes are
      ** a 32-bit counter that is incremented with each change.  The
      ** other bytes change randomly with each file change when
      ** a codec is in use.
      ** 
      ** There is a vanishingly small chance that a change will not be 
      ** detected.  The chance of an undetected change is so small that
................................................................................

    {
      sqlite3_pcache_page *pBase;
      pBase = sqlite3PcacheFetch(pPager->pPCache, pgno, 3);
      if( pBase==0 ){
        rc = sqlite3PcacheFetchStress(pPager->pPCache, pgno, &pBase);
        if( rc!=SQLITE_OK ) goto pager_acquire_err;




      }

      pPg = *ppPage = sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pBase);
      if( pPg==0 ) rc = SQLITE_NOMEM;

    }
  }

  if( rc!=SQLITE_OK ){
    /* Either the call to sqlite3PcacheFetch() returned an error or the
    ** pager was already in the error-state when this function was called.
    ** Set pPg to 0 and jump to the exception handler.  */
    pPg = 0;
    goto pager_acquire_err;
  }

  assert( (*ppPage)->pgno==pgno );
  assert( (*ppPage)->pPager==pPager || (*ppPage)->pPager==0 );

  if( (*ppPage)->pPager && !noContent ){
    /* In this case the pcache already contains an initialized copy of
    ** the page. Return without further ado.  */
    assert( pgno<=PAGER_MAX_PGNO && pgno!=PAGER_MJ_PGNO(pPager) );
    pPager->aStat[PAGER_STAT_HIT]++;
    return SQLITE_OK;

  }else{
    /* The pager cache has created a new page. Its content needs to 
    ** be initialized.  */

    pPg = *ppPage;
    pPg->pPager = pPager;

    /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
    ** number greater than this, or the unused locking-page, is requested. */
    if( pgno>PAGER_MAX_PGNO || pgno==PAGER_MJ_PGNO(pPager) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto pager_acquire_err;
................................................................................
SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
  sqlite3_pcache_page *pPage;
  assert( pPager!=0 );
  assert( pgno!=0 );
  assert( pPager->pPCache!=0 );
  pPage = sqlite3PcacheFetch(pPager->pPCache, pgno, 0);
  assert( pPage==0 || pPager->hasBeenUsed );

  return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage);
}

/*
** Release a page reference.
**
** If the number of references to the page drop to zero, then the
................................................................................
    assert( rc!=SQLITE_OK || pPager->eState==PAGER_WRITER_LOCKED );
    assert( assert_pager_state(pPager) );
  }

  PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
  return rc;
}






















































/*
** Mark a single data page as writeable. The page is written into the 
** main journal or sub-journal as required. If the page is written into
** one of the journals, the corresponding bit is set in the 
** Pager.pInJournal bitvec and the PagerSavepoint.pInSavepoint bitvecs
** of any open savepoints as appropriate.
*/
static int pager_write(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;
  int inJournal;

  /* This routine is not called unless a write-transaction has already 
  ** been started. The journal file may or may not be open at this point.
  ** It is never called in the ERROR state.
  */
  assert( pPager->eState==PAGER_WRITER_LOCKED
       || pPager->eState==PAGER_WRITER_CACHEMOD
       || pPager->eState==PAGER_WRITER_DBMOD
  );
  assert( assert_pager_state(pPager) );
  assert( pPager->errCode==0 );
  assert( pPager->readOnly==0 );

  CHECK_PAGE(pPg);

  /* The journal file needs to be opened. Higher level routines have already
  ** obtained the necessary locks to begin the write-transaction, but the
  ** rollback journal might not yet be open. Open it now if this is the case.
  **
  ** This is done before calling sqlite3PcacheMakeDirty() on the page. 
................................................................................
  if( pPager->eState==PAGER_WRITER_LOCKED ){
    rc = pager_open_journal(pPager);
    if( rc!=SQLITE_OK ) return rc;
  }
  assert( pPager->eState>=PAGER_WRITER_CACHEMOD );
  assert( assert_pager_state(pPager) );

  /* Mark the page as dirty.  If the page has already been written
  ** to the journal then we can return right away.
  */
  sqlite3PcacheMakeDirty(pPg);
  inJournal = pageInJournal(pPager, pPg);
  if( inJournal && (pPager->nSavepoint==0 || !subjRequiresPage(pPg)) ){
    assert( !pagerUseWal(pPager) );
  }else{
  
    /* The transaction journal now exists and we have a RESERVED or an
    ** EXCLUSIVE lock on the main database file.  Write the current page to
    ** the transaction journal if it is not there already.



    */
    if( !inJournal && !pagerUseWal(pPager) ){
      assert( pagerUseWal(pPager)==0 );
      if( pPg->pgno<=pPager->dbOrigSize && isOpen(pPager->jfd) ){
        u32 cksum;
        char *pData2;
        i64 iOff = pPager->journalOff;

        /* We should never write to the journal file the page that
        ** contains the database locks.  The following assert verifies
        ** that we do not. */
        assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );

        assert( pPager->journalHdr<=pPager->journalOff );
        CODEC2(pPager, pPg->pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
        cksum = pager_cksum(pPager, (u8*)pData2);

        /* Even if an IO or diskfull error occurs while journalling the
        ** page in the block above, set the need-sync flag for the page.
        ** Otherwise, when the transaction is rolled back, the logic in
        ** playback_one_page() will think that the page needs to be restored
        ** in the database file. And if an IO error occurs while doing so,
        ** then corruption may follow.
        */
        pPg->flags |= PGHDR_NEED_SYNC;

        rc = write32bits(pPager->jfd, iOff, pPg->pgno);
        if( rc!=SQLITE_OK ) return rc;
        rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize, iOff+4);
        if( rc!=SQLITE_OK ) return rc;
        rc = write32bits(pPager->jfd, iOff+pPager->pageSize+4, cksum);
        if( rc!=SQLITE_OK ) return rc;

        IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno, 
                 pPager->journalOff, pPager->pageSize));
        PAGER_INCR(sqlite3_pager_writej_count);
        PAGERTRACE(("JOURNAL %d page %d needSync=%d hash(%08x)\n",
             PAGERID(pPager), pPg->pgno, 
             ((pPg->flags&PGHDR_NEED_SYNC)?1:0), pager_pagehash(pPg)));

        pPager->journalOff += 8 + pPager->pageSize;
        pPager->nRec++;
        assert( pPager->pInJournal!=0 );
        rc = sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
        testcase( rc==SQLITE_NOMEM );
        assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
        rc |= addToSavepointBitvecs(pPager, pPg->pgno);




        if( rc!=SQLITE_OK ){
          assert( rc==SQLITE_NOMEM );
          return rc;
        }
      }else{
        if( pPager->eState!=PAGER_WRITER_DBMOD ){
          pPg->flags |= PGHDR_NEED_SYNC;
        }
        PAGERTRACE(("APPEND %d page %d needSync=%d\n",
                PAGERID(pPager), pPg->pgno,
               ((pPg->flags&PGHDR_NEED_SYNC)?1:0)));
      }
    }
  







    /* If the statement journal is open and the page is not in it,
    ** then write the current page to the statement journal.  Note that
    ** the statement journal format differs from the standard journal format
    ** in that it omits the checksums and the header.
    */
    if( pPager->nSavepoint>0 && subjRequiresPage(pPg) ){
      rc = subjournalPage(pPg);
    }
  }

  /* Update the database size and return.
  */
  if( pPager->dbSize<pPg->pgno ){
    pPager->dbSize = pPg->pgno;
  }
  return rc;
}

/*
................................................................................
** This is a variant of sqlite3PagerWrite() that runs when the sector size
** is larger than the page size.  SQLite makes the (reasonable) assumption that
** all bytes of a sector are written together by hardware.  Hence, all bytes of
** a sector need to be journalled in case of a power loss in the middle of
** a write.
**
** Usually, the sector size is less than or equal to the page size, in which
** case pages can be individually written.  This routine only runs in the exceptional
** case where the page size is smaller than the sector size.
*/
static SQLITE_NOINLINE int pagerWriteLargeSector(PgHdr *pPg){
  int rc = SQLITE_OK;            /* Return code */
  Pgno nPageCount;               /* Total number of pages in database file */
  Pgno pg1;                      /* First page of the sector pPg is located on. */
  int nPage = 0;                 /* Number of pages starting at pg1 to journal */
  int ii;                        /* Loop counter */
  int needSync = 0;              /* True if any page has PGHDR_NEED_SYNC */
  Pager *pPager = pPg->pPager;   /* The pager that owns pPg */
  Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);

  /* Set the doNotSpill NOSYNC bit to 1. This is because we cannot allow
  ** a journal header to be written between the pages journaled by
  ** this function.
  */
  assert( !MEMDB );
................................................................................
** fit on a single disk sector. In this case all co-resident pages
** must have been written to the journal file before returning.
**
** If an error occurs, SQLITE_NOMEM or an IO error code is returned
** as appropriate. Otherwise, SQLITE_OK.
*/
SQLITE_PRIVATE int sqlite3PagerWrite(PgHdr *pPg){

  assert( (pPg->flags & PGHDR_MMAP)==0 );
  assert( pPg->pPager->eState>=PAGER_WRITER_LOCKED );
  assert( pPg->pPager->eState!=PAGER_ERROR );
  assert( assert_pager_state(pPg->pPager) );



  if( pPg->pPager->sectorSize > (u32)pPg->pPager->pageSize ){
    return pagerWriteLargeSector(pPg);
  }else{
    return pager_write(pPg);
  }
}

/*
** Return TRUE if the page given in the argument was previously passed
** to sqlite3PagerWrite().  In other words, return TRUE if it is ok
** to change the content of the page.
*/
#ifndef NDEBUG
SQLITE_PRIVATE int sqlite3PagerIswriteable(DbPage *pPg){
  return pPg->flags&PGHDR_DIRTY;
}
#endif

/*
** A call to this routine tells the pager that it is not necessary to
** write the information on page pPg back to the disk, even though
** that page might be marked as dirty.  This happens, for example, when
................................................................................
*/
SQLITE_PRIVATE void sqlite3PagerDontWrite(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  if( (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){
    PAGERTRACE(("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager)));
    IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
    pPg->flags |= PGHDR_DONT_WRITE;

    pager_set_pagehash(pPg);
  }
}

/*
** This routine is called to increment the value of the database file 
** change-counter, stored as a 4-byte big-endian integer starting at 
................................................................................
** to make up the difference. If the number of savepoints is already
** equal to nSavepoint, then this function is a no-op.
**
** If a memory allocation fails, SQLITE_NOMEM is returned. If an error 
** occurs while opening the sub-journal file, then an IO error code is
** returned. Otherwise, SQLITE_OK.
*/
SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
  int rc = SQLITE_OK;                       /* Return code */
  int nCurrent = pPager->nSavepoint;        /* Current number of savepoints */



  assert( pPager->eState>=PAGER_WRITER_LOCKED );
  assert( assert_pager_state(pPager) );

  if( nSavepoint>nCurrent && pPager->useJournal ){
    int ii;                                 /* Iterator variable */
    PagerSavepoint *aNew;                   /* New Pager.aSavepoint array */

    /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
    ** if the allocation fails. Otherwise, zero the new portion in case a 
    ** malloc failure occurs while populating it in the for(...) loop below.
    */
    aNew = (PagerSavepoint *)sqlite3Realloc(
        pPager->aSavepoint, sizeof(PagerSavepoint)*nSavepoint
    );
    if( !aNew ){
      return SQLITE_NOMEM;
    }
    memset(&aNew[nCurrent], 0, (nSavepoint-nCurrent) * sizeof(PagerSavepoint));
    pPager->aSavepoint = aNew;

    /* Populate the PagerSavepoint structures just allocated. */
    for(ii=nCurrent; ii<nSavepoint; ii++){
      aNew[ii].nOrig = pPager->dbSize;
      if( isOpen(pPager->jfd) && pPager->journalOff>0 ){
        aNew[ii].iOffset = pPager->journalOff;
      }else{
        aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
      }
      aNew[ii].iSubRec = pPager->nSubRec;
      aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
      if( !aNew[ii].pInSavepoint ){
        return SQLITE_NOMEM;
      }
      if( pagerUseWal(pPager) ){
        sqlite3WalSavepoint(pPager->pWal, aNew[ii].aWalData);
      }
      pPager->nSavepoint = ii+1;
    }
    assert( pPager->nSavepoint==nSavepoint );
    assertTruncateConstraint(pPager);

  }







  return rc;
}



/*
** This function is called to rollback or release (commit) a savepoint.
** The savepoint to release or rollback need not be the most recently 
** created savepoint.
**
** Parameter op is always either SAVEPOINT_ROLLBACK or SAVEPOINT_RELEASE.
................................................................................
  ** be possible to restore its contents when the "ROLLBACK TO one"
  ** statement were is processed.
  **
  ** subjournalPage() may need to allocate space to store pPg->pgno into
  ** one or more savepoint bitvecs. This is the reason this function
  ** may return SQLITE_NOMEM.
  */
  if( pPg->flags&PGHDR_DIRTY
   && subjRequiresPage(pPg)
   && SQLITE_OK!=(rc = subjournalPage(pPg))
  ){
    return rc;
  }

  PAGERTRACE(("MOVE %d page %d (needSync=%d) moves to %d\n", 
      PAGERID(pPager), pPg->pgno, (pPg->flags&PGHDR_NEED_SYNC)?1:0, pgno));
  IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
................................................................................
  u16 aiOvfl[5];       /* Insert the i-th overflow cell before the aiOvfl-th
                       ** non-overflow cell */
  u8 *apOvfl[5];       /* Pointers to the body of overflow cells */
  BtShared *pBt;       /* Pointer to BtShared that this page is part of */
  u8 *aData;           /* Pointer to disk image of the page data */
  u8 *aDataEnd;        /* One byte past the end of usable data */
  u8 *aCellIdx;        /* The cell index area */

  DbPage *pDbPage;     /* Pager page handle */
  u16 (*xCellSize)(MemPage*,u8*);             /* cellSizePtr method */
  void (*xParseCell)(MemPage*,u8*,CellInfo*); /* btreeParseCell method */
  Pgno pgno;           /* Page number for this page */
};

/*
................................................................................
**    eState==SKIPNEXT && skipNext>0:  Next sqlite3BtreeNext() is no-op.
**    eState==SKIPNEXT && skipNext<0:  Next sqlite3BtreePrevious() is no-op.
**    eState==FAULT:                   Cursor fault with skipNext as error code.
*/
struct BtCursor {
  Btree *pBtree;            /* The Btree to which this cursor belongs */
  BtShared *pBt;            /* The BtShared this cursor points to */
  BtCursor *pNext, *pPrev;  /* Forms a linked list of all cursors */
  struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */
  Pgno *aOverflow;          /* Cache of overflow page locations */
  CellInfo info;            /* A parse of the cell we are pointing at */
  i64 nKey;                 /* Size of pKey, or last integer key */
  void *pKey;               /* Saved key that was cursor last known position */
  Pgno pgnoRoot;            /* The root page of this tree */
  int nOvflAlloc;           /* Allocated size of aOverflow[] array */
  int skipNext;    /* Prev() is noop if negative. Next() is noop if positive.
                   ** Error code if eState==CURSOR_FAULT */
  u8 curFlags;              /* zero or more BTCF_* flags defined below */

  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
  u8 hints;                             /* As configured by CursorSetHints() */



  i16 iPage;                            /* Index of current page in apPage */



  u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
};

/*
** Legal values for BtCursor.curFlags
*/
#define BTCF_WriteFlag    0x01   /* True if a write cursor */
#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
#define BTCF_AtLast       0x08   /* Cursor is pointing ot the last entry */
#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */


/*
** Potential values for BtCursor.eState.
**
** CURSOR_INVALID:
**   Cursor does not point to a valid entry. This can happen (for example) 
**   because the table is empty or because BtreeCursorFirst() has not been
................................................................................
** Routines to read or write a two- and four-byte big-endian integer values.
*/
#define get2byte(x)   ((x)[0]<<8 | (x)[1])
#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
#define get4byte sqlite3Get4byte
#define put4byte sqlite3Put4byte
















/************** End of btreeInt.h ********************************************/
/************** Continuing where we left off in btmutex.c ********************/
#ifndef SQLITE_OMIT_SHARED_CACHE
#if SQLITE_THREADSAFE

/*
** Obtain the BtShared mutex associated with B-Tree handle p. Also,
................................................................................

  /* If this is an intKey table, then the above call to BtreeKeySize()
  ** stores the integer key in pCur->nKey. In this case this value is
  ** all that is required. Otherwise, if pCur is not open on an intKey
  ** table, then malloc space for and store the pCur->nKey bytes of key 
  ** data.
  */
  if( 0==pCur->apPage[0]->intKey ){
    void *pKey = sqlite3Malloc( pCur->nKey );
    if( pKey ){
      rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
      if( rc==SQLITE_OK ){
        pCur->pKey = pKey;
      }else{
        sqlite3_free(pKey);
      }
    }else{
      rc = SQLITE_NOMEM;
    }
  }
  assert( !pCur->apPage[0]->intKey || !pCur->pKey );

  if( rc==SQLITE_OK ){
    btreeReleaseAllCursorPages(pCur);
    pCur->eState = CURSOR_REQUIRESEEK;
  }

  invalidateOverflowCache(pCur);
................................................................................
/*
** Save the positions of all cursors (except pExcept) that are open on
** the table with root-page iRoot.  "Saving the cursor position" means that
** the location in the btree is remembered in such a way that it can be
** moved back to the same spot after the btree has been modified.  This
** routine is called just before cursor pExcept is used to modify the
** table, for example in BtreeDelete() or BtreeInsert().









**
** Implementation note:  This routine merely checks to see if any cursors
** need to be saved.  It calls out to saveCursorsOnList() in the (unusual)
** event that cursors are in need to being saved.
*/
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
  BtCursor *p;
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( pExcept==0 || pExcept->pBt==pBt );
  for(p=pBt->pCursor; p; p=p->pNext){
    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ) break;
  }
  return p ? saveCursorsOnList(p, iRoot, pExcept) : SQLITE_OK;


}

/* This helper routine to saveAllCursors does the actual work of saving
** the cursors if and when a cursor is found that actually requires saving.
** The common case is that no cursors need to be saved, so this routine is
** broken out from its caller to avoid unnecessary stack pointer movement.
*/
................................................................................
  #define ptrmapPutOvflPtr(x, y, rc)
#endif

/*
** Given a btree page and a cell index (0 means the first cell on
** the page, 1 means the second cell, and so forth) return a pointer
** to the cell content.



**
** This routine works only for pages that do not contain overflow cells.
*/
#define findCell(P,I) \
  ((P)->aData + ((P)->maskPage & get2byte(&(P)->aCellIdx[2*(I)])))




/*
** This is common tail processing for btreeParseCellPtr() and
** btreeParseCellPtrIndex() for the case when the cell does not fit entirely
** on a single B-tree page.  Make necessary adjustments to the CellInfo
** structure.
*/
................................................................................
    assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
    pPage->maskPage = (u16)(pBt->pageSize - 1);
    pPage->nOverflow = 0;
    usableSize = pBt->usableSize;
    pPage->cellOffset = cellOffset = hdr + 8 + pPage->childPtrSize;
    pPage->aDataEnd = &data[usableSize];
    pPage->aCellIdx = &data[cellOffset];

    /* EVIDENCE-OF: R-58015-48175 The two-byte integer at offset 5 designates
    ** the start of the cell content area. A zero value for this integer is
    ** interpreted as 65536. */
    top = get2byteNotZero(&data[hdr+5]);
    /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
    ** number of cells on the page. */
    pPage->nCell = get2byte(&data[hdr+3]);
................................................................................
    iCellLast = usableSize - 4;
    if( pBt->db->flags & SQLITE_CellSizeCk ){
      int i;            /* Index into the cell pointer array */
      int sz;           /* Size of a cell */

      if( !pPage->leaf ) iCellLast--;
      for(i=0; i<pPage->nCell; i++){
        pc = get2byte(&data[cellOffset+i*2]);
        testcase( pc==iCellFirst );
        testcase( pc==iCellLast );
        if( pc<iCellFirst || pc>iCellLast ){
          return SQLITE_CORRUPT_BKPT;
        }
        sz = pPage->xCellSize(pPage, &data[pc]);
        testcase( pc+sz==usableSize );
................................................................................
  data[hdr+7] = 0;
  put2byte(&data[hdr+5], pBt->usableSize);
  pPage->nFree = (u16)(pBt->usableSize - first);
  decodeFlags(pPage, flags);
  pPage->cellOffset = first;
  pPage->aDataEnd = &data[pBt->usableSize];
  pPage->aCellIdx = &data[first];

  pPage->nOverflow = 0;
  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
  pPage->maskPage = (u16)(pBt->pageSize - 1);
  pPage->nCell = 0;
  pPage->isInit = 1;
}

................................................................................
*/
static MemPage *btreePageFromDbPage(DbPage *pDbPage, Pgno pgno, BtShared *pBt){
  MemPage *pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage);
  pPage->aData = sqlite3PagerGetData(pDbPage);
  pPage->pDbPage = pDbPage;
  pPage->pBt = pBt;
  pPage->pgno = pgno;
  pPage->hdrOffset = pPage->pgno==1 ? 100 : 0;
  return pPage; 
}

/*
** Get a page from the pager.  Initialize the MemPage.pBt and
** MemPage.aData elements if needed.  See also: btreeGetUnusedPage().
**
................................................................................
SQLITE_PRIVATE u32 sqlite3BtreeLastPage(Btree *p){
  assert( sqlite3BtreeHoldsMutex(p) );
  assert( ((p->pBt->nPage)&0x8000000)==0 );
  return btreePagecount(p->pBt);
}

/*
** Get a page from the pager and initialize it.  This routine is just a
** convenience wrapper around separate calls to btreeGetPage() and 
** btreeInitPage().


**



** If an error occurs, then the value *ppPage is set to is undefined. It
** may remain unchanged, or it may be set to an invalid value.
*/
static int getAndInitPage(
  BtShared *pBt,                  /* The database file */
  Pgno pgno,                      /* Number of the page to get */
  MemPage **ppPage,               /* Write the page pointer here */

  int bReadonly                   /* PAGER_GET_READONLY or 0 */
){
  int rc;

  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( bReadonly==PAGER_GET_READONLY || bReadonly==0 );




  if( pgno>btreePagecount(pBt) ){
    rc = SQLITE_CORRUPT_BKPT;
  }else{
    rc = btreeGetPage(pBt, pgno, ppPage, bReadonly);






    if( rc==SQLITE_OK && (*ppPage)->isInit==0 ){
      rc = btreeInitPage(*ppPage);
      if( rc!=SQLITE_OK ){
        releasePage(*ppPage);

      }
    }
  }













  testcase( pgno==0 );
  assert( pgno!=0 || rc==SQLITE_CORRUPT );
  return rc;
}

/*
** Release a MemPage.  This should be called once for each prior
** call to btreeGetPage.
*/
static void releasePage(MemPage *pPage){
  if( pPage ){
    assert( pPage->aData );
    assert( pPage->pBt );
    assert( pPage->pDbPage!=0 );
    assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
    assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData );
    assert( sqlite3_mutex_held(pPage->pBt->mutex) );
    sqlite3PagerUnrefNotNull(pPage->pDbPage);
  }


}

/*
** Get an unused page.
**
** This works just like btreeGetPage() with the addition:
**
................................................................................
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE );
  if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){
    MemPage *pPage1 = pBt->pPage1;
    assert( pPage1->aData );
    assert( sqlite3PagerRefcount(pBt->pPager)==1 );
    pBt->pPage1 = 0;
    releasePage(pPage1);
  }
}

/*
** If pBt points to an empty file then convert that empty file
** into a new empty database by initializing the first page of
** the database.
................................................................................
  Btree *p,                              /* The btree */
  int iTable,                            /* Root page of table to open */
  int wrFlag,                            /* 1 to write. 0 read-only */
  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
  BtCursor *pCur                         /* Space for new cursor */
){
  BtShared *pBt = p->pBt;                /* Shared b-tree handle */


  assert( sqlite3BtreeHoldsMutex(p) );
  assert( wrFlag==0 || wrFlag==1 );

  /* The following assert statements verify that if this is a sharable 
  ** b-tree database, the connection is holding the required table locks, 
  ** and that no other connection has any open cursor that conflicts with 
................................................................................
  assert( hasSharedCacheTableLock(p, iTable, pKeyInfo!=0, wrFlag+1) );
  assert( wrFlag==0 || !hasReadConflicts(p, iTable) );

  /* Assert that the caller has opened the required transaction. */
  assert( p->inTrans>TRANS_NONE );
  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
  assert( pBt->pPage1 && pBt->pPage1->aData );

  if( NEVER(wrFlag && (pBt->btsFlags & BTS_READ_ONLY)!=0) ){
    return SQLITE_READONLY;
  }
  if( wrFlag ){
    allocateTempSpace(pBt);
    if( pBt->pTmpSpace==0 ) return SQLITE_NOMEM;
  }
  if( iTable==1 && btreePagecount(pBt)==0 ){
    assert( wrFlag==0 );
    iTable = 0;
................................................................................
  pCur->pgnoRoot = (Pgno)iTable;
  pCur->iPage = -1;
  pCur->pKeyInfo = pKeyInfo;
  pCur->pBtree = p;
  pCur->pBt = pBt;
  assert( wrFlag==0 || wrFlag==BTCF_WriteFlag );
  pCur->curFlags = wrFlag;



  pCur->pNext = pBt->pCursor;
  if( pCur->pNext ){
    pCur->pNext->pPrev = pCur;



  }


  pBt->pCursor = pCur;
  pCur->eState = CURSOR_INVALID;
  return SQLITE_OK;
}
SQLITE_PRIVATE int sqlite3BtreeCursor(
  Btree *p,                                   /* The btree */
  int iTable,                                 /* Root page of table to open */
................................................................................
SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
  Btree *pBtree = pCur->pBtree;
  if( pBtree ){
    int i;
    BtShared *pBt = pCur->pBt;
    sqlite3BtreeEnter(pBtree);
    sqlite3BtreeClearCursor(pCur);
    if( pCur->pPrev ){

      pCur->pPrev->pNext = pCur->pNext;
    }else{



      pBt->pCursor = pCur->pNext;

    }
    if( pCur->pNext ){
      pCur->pNext->pPrev = pCur->pPrev;

    }
    for(i=0; i<=pCur->iPage; i++){
      releasePage(pCur->apPage[i]);
    }
    unlockBtreeIfUnused(pBt);
    sqlite3_free(pCur->aOverflow);
    /* sqlite3_free(pCur); */
................................................................................
**
** This function returns SQLITE_CORRUPT if the page-header flags field of
** the new child page does not match the flags field of the parent (i.e.
** if an intkey page appears to be the parent of a non-intkey page, or
** vice-versa).
*/
static int moveToChild(BtCursor *pCur, u32 newPgno){
  int rc;
  int i = pCur->iPage;
  MemPage *pNewPage;
  BtShared *pBt = pCur->pBt;

  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
  assert( pCur->iPage>=0 );
  if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
    return SQLITE_CORRUPT_BKPT;
  }
  rc = getAndInitPage(pBt, newPgno, &pNewPage,
               (pCur->curFlags & BTCF_WriteFlag)==0 ? PAGER_GET_READONLY : 0);
  if( rc ) return rc;
  pCur->apPage[i+1] = pNewPage;
  pCur->aiIdx[i+1] = 0;
  pCur->iPage++;

  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  if( pNewPage->nCell<1 || pNewPage->intKey!=pCur->apPage[i]->intKey ){
    return SQLITE_CORRUPT_BKPT;
  }
  return SQLITE_OK;




}

#if SQLITE_DEBUG
/*
** Page pParent is an internal (non-leaf) tree page. This function 
** asserts that page number iChild is the left-child if the iIdx'th
** cell in page pParent. Or, if iIdx is equal to the total number of
................................................................................
  assert( pCur->apPage[pCur->iPage] );
  assertParentIndex(
    pCur->apPage[pCur->iPage-1], 
    pCur->aiIdx[pCur->iPage-1], 
    pCur->apPage[pCur->iPage]->pgno
  );
  testcase( pCur->aiIdx[pCur->iPage-1] > pCur->apPage[pCur->iPage-1]->nCell );

  releasePage(pCur->apPage[pCur->iPage]);
  pCur->iPage--;
  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);

}

/*
** Move the cursor to point to the root page of its b-tree structure.
**
** If the table has a virtual root page, then the cursor is moved to point
** to the virtual root page instead of the actual root page. A table has a
................................................................................
      assert( pCur->skipNext!=SQLITE_OK );
      return pCur->skipNext;
    }
    sqlite3BtreeClearCursor(pCur);
  }

  if( pCur->iPage>=0 ){


    while( pCur->iPage ) releasePage(pCur->apPage[pCur->iPage--]);

  }else if( pCur->pgnoRoot==0 ){
    pCur->eState = CURSOR_INVALID;
    return SQLITE_OK;
  }else{

    rc = getAndInitPage(pCur->pBtree->pBt, pCur->pgnoRoot, &pCur->apPage[0],
                 (pCur->curFlags & BTCF_WriteFlag)==0 ? PAGER_GET_READONLY : 0);

    if( rc!=SQLITE_OK ){
      pCur->eState = CURSOR_INVALID;
      return rc;
    }
    pCur->iPage = 0;

  }
  pRoot = pCur->apPage[0];
  assert( pRoot->pgno==pCur->pgnoRoot );

  /* If pCur->pKeyInfo is not NULL, then the caller that opened this cursor
  ** expected to open it on an index b-tree. Otherwise, if pKeyInfo is
  ** NULL, the caller expects a table b-tree. If this is not the case,
................................................................................
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  assert( pRes );
  assert( (pIdxKey==0)==(pCur->pKeyInfo==0) );

  /* If the cursor is already positioned at the point we are trying
  ** to move to, then just return without doing any work */
  if( pCur->eState==CURSOR_VALID && (pCur->curFlags & BTCF_ValidNKey)!=0
   && pCur->apPage[0]->intKey 
  ){
    if( pCur->info.nKey==intKey ){
      *pRes = 0;
      return SQLITE_OK;
    }
    if( (pCur->curFlags & BTCF_AtLast)!=0 && pCur->info.nKey<intKey ){
      *pRes = -1;
................................................................................
  assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->isInit );
  assert( pCur->eState==CURSOR_INVALID || pCur->apPage[pCur->iPage]->nCell>0 );
  if( pCur->eState==CURSOR_INVALID ){
    *pRes = -1;
    assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->nCell==0 );
    return SQLITE_OK;
  }
  assert( pCur->apPage[0]->intKey || pIdxKey );

  for(;;){
    int lwr, upr, idx, c;
    Pgno chldPg;
    MemPage *pPage = pCur->apPage[pCur->iPage];
    u8 *pCell;                          /* Pointer to current cell in pPage */

    /* pPage->nCell must be greater than zero. If this is the root-page
................................................................................
    upr = pPage->nCell-1;
    assert( biasRight==0 || biasRight==1 );
    idx = upr>>(1-biasRight); /* idx = biasRight ? upr : (lwr+upr)/2; */
    pCur->aiIdx[pCur->iPage] = (u16)idx;
    if( xRecordCompare==0 ){
      for(;;){
        i64 nCellKey;
        pCell = findCell(pPage, idx) + pPage->childPtrSize;
        if( pPage->intKeyLeaf ){
          while( 0x80 <= *(pCell++) ){
            if( pCell>=pPage->aDataEnd ) return SQLITE_CORRUPT_BKPT;
          }
        }
        getVarint(pCell, (u64*)&nCellKey);
        if( nCellKey<intKey ){
................................................................................
        }
        assert( lwr+upr>=0 );
        idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2; */
      }
    }else{
      for(;;){
        int nCell;  /* Size of the pCell cell in bytes */
        pCell = findCell(pPage, idx) + pPage->childPtrSize;

        /* The maximum supported page-size is 65536 bytes. This means that
        ** the maximum number of record bytes stored on an index B-Tree
        ** page is less than 16384 bytes and may be stored as a 2-byte
        ** varint. This information is used to attempt to avoid parsing 
        ** the entire cell by checking for the cases where the record is 
        ** stored entirely within the b-tree page by inspecting the first 
................................................................................
  
  /* Fill in the payload size */
  if( pPage->intKey ){
    pSrc = pData;
    nSrc = nData;
    nData = 0;
  }else{ 
    if( NEVER(nKey>0x7fffffff || pKey==0) ){
      return SQLITE_CORRUPT_BKPT;
    }
    nPayload = (int)nKey;
    pSrc = pKey;
    nSrc = (int)nKey;
  }
  if( nPayload<=pPage->maxLocal ){
    n = nHeader + nPayload;
    testcase( n==3 );
................................................................................

  put2byte(&aData[hdr+3], pPg->nCell);
  put2byte(&aData[hdr+5], pData - aData);

#ifdef SQLITE_DEBUG
  for(i=0; i<nNew && !CORRUPT_DB; i++){
    u8 *pCell = pCArray->apCell[i+iNew];
    int iOff = get2byte(&pPg->aCellIdx[i*2]);
    if( pCell>=aData && pCell<&aData[pPg->pBt->usableSize] ){
      pCell = &pTmp[pCell - aData];
    }
    assert( 0==memcmp(pCell, &aData[iOff],
            pCArray->pRef->xCellSize(pCArray->pRef, pCArray->apCell[i+iNew])) );
  }
#endif
................................................................................
  if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
    pRight = &pParent->aData[pParent->hdrOffset+8];
  }else{
    pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
  }
  pgno = get4byte(pRight);
  while( 1 ){
    rc = getAndInitPage(pBt, pgno, &apOld[i], 0);
    if( rc ){
      memset(apOld, 0, (i+1)*sizeof(MemPage*));
      goto balance_cleanup;
    }
    nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
    if( (i--)==0 ) break;

................................................................................
    ** first.
    */
    memset(&b.szCell[b.nCell], 0, sizeof(b.szCell[0])*limit);
    if( pOld->nOverflow>0 ){
      memset(&b.szCell[b.nCell+limit], 0, sizeof(b.szCell[0])*pOld->nOverflow);
      limit = pOld->aiOvfl[0];
      for(j=0; j<limit; j++){
        b.apCell[b.nCell] = aData + (maskPage & get2byte(piCell));
        piCell += 2;
        b.nCell++;
      }
      for(k=0; k<pOld->nOverflow; k++){
        assert( k==0 || pOld->aiOvfl[k-1]+1==pOld->aiOvfl[k] );/* NOTE 1 */
        b.apCell[b.nCell] = pOld->apOvfl[k];
        b.nCell++;
      }
    }
    piEnd = aData + pOld->cellOffset + 2*pOld->nCell;
    while( piCell<piEnd ){
      assert( b.nCell<nMaxCells );
      b.apCell[b.nCell] = aData + (maskPage & get2byte(piCell));
      piCell += 2;
      b.nCell++;
    }

    cntOld[i] = b.nCell;
    if( i<nOld-1 && !leafData){
      u16 sz = (u16)szNew[i];
................................................................................
  ** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the 
  ** integer key to use. It then calls this function to actually insert the 
  ** data into the intkey B-Tree. In this case btreeMoveto() recognizes
  ** that the cursor is already where it needs to be and returns without
  ** doing any work. To avoid thwarting these optimizations, it is important
  ** not to clear the cursor here.
  */

  rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
  if( rc ) return rc;


  if( pCur->pKeyInfo==0 ){

    /* If this is an insert into a table b-tree, invalidate any incrblob 
    ** cursors open on the row being replaced */
    invalidateIncrblobCursors(p, nKey, 0);

    /* If the cursor is currently on the last row and we are appending a
    ** new row onto the end, set the "loc" to avoid an unnecessary btreeMoveto()
    ** call */
    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && nKey>0
      && pCur->info.nKey==nKey-1 ){
      loc = -1;
    }


  }

  if( !loc ){

    rc = btreeMoveto(pCur, pKey, nKey, appendBias, &loc);
    if( rc ) return rc;
  }
  assert( pCur->eState==CURSOR_VALID || (pCur->eState==CURSOR_INVALID && loc) );

  pPage = pCur->apPage[pCur->iPage];
  assert( pPage->intKey || nKey>=0 );
................................................................................

  assert( cursorHoldsMutex(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( pCur->curFlags & BTCF_WriteFlag );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
  assert( !hasReadConflicts(p, pCur->pgnoRoot) );


  if( NEVER(pCur->aiIdx[pCur->iPage]>=pCur->apPage[pCur->iPage]->nCell) 
   || NEVER(pCur->eState!=CURSOR_VALID)
  ){
    return SQLITE_ERROR;  /* Something has gone awry. */
  }

  iCellDepth = pCur->iPage;
  iCellIdx = pCur->aiIdx[iCellDepth];
  pPage = pCur->apPage[iCellDepth];
  pCell = findCell(pPage, iCellIdx);

  /* If the page containing the entry to delete is not a leaf page, move
................................................................................
  }

  /* Save the positions of any other cursors open on this table before
  ** making any modifications. Make the page containing the entry to be 
  ** deleted writable. Then free any overflow pages associated with the 
  ** entry and finally remove the cell itself from within the page.  
  */

  rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
  if( rc ) return rc;


  /* If this is a delete operation to remove a row from a table b-tree,
  ** invalidate any incrblob cursors open on the row being deleted.  */
  if( pCur->pKeyInfo==0 ){
    invalidateIncrblobCursors(p, pCur->info.nKey, 0);
  }

................................................................................
  int hdr;
  u16 szCell;

  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pgno>btreePagecount(pBt) ){
    return SQLITE_CORRUPT_BKPT;
  }
  rc = getAndInitPage(pBt, pgno, &pPage, 0);
  if( rc ) return rc;
  if( pPage->bBusy ){
    rc = SQLITE_CORRUPT_BKPT;
    goto cleardatabasepage_out;
  }
  pPage->bBusy = 1;
  hdr = pPage->hdrOffset;
................................................................................
    nCell = get2byte(&data[hdr+3]);
    /* EVIDENCE-OF: R-23882-45353 The cell pointer array of a b-tree page
    ** immediately follows the b-tree page header. */
    cellStart = hdr + 12 - 4*pPage->leaf;
    /* EVIDENCE-OF: R-02776-14802 The cell pointer array consists of K 2-byte
    ** integer offsets to the cell contents. */
    for(i=0; i<nCell; i++){
      int pc = get2byte(&data[cellStart+i*2]);
      u32 size = 65536;
      if( pc<=usableSize-4 ){
        size = pPage->xCellSize(pPage, &data[pc]);
      }
      if( (int)(pc+size-1)>=usableSize ){
        pCheck->zPfx = 0;
        checkAppendMsg(pCheck,
................................................................................
  p->bIsReader = 0;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;

    /* NOTE: Be sure to update mkopcodeh.awk when adding or removing
    ** cases from this switch! */
    switch( opcode ){
      case OP_Function:
      case OP_AggStep: {
        if( pOp->p5>nMaxArgs ) nMaxArgs = pOp->p5;
        break;
      }
      case OP_Transaction: {
        if( pOp->p2!=0 ) p->readOnly = 0;
        /* fall thru */
      }
      case OP_AutoCommit:
      case OP_Savepoint: {
        p->bIsReader = 1;
................................................................................
/*
** Delete a P4 value if necessary.
*/
static void freeP4(sqlite3 *db, int p4type, void *p4){
  if( p4 ){
    assert( db );
    switch( p4type ){




      case P4_REAL:
      case P4_INT64:
      case P4_DYNAMIC:
      case P4_INTARRAY: {
        sqlite3DbFree(db, p4);
        break;
      }
................................................................................
      break;
    }
    case P4_FUNCDEF: {
      FuncDef *pDef = pOp->p4.pFunc;
      sqlite3_snprintf(nTemp, zTemp, "%s(%d)", pDef->zName, pDef->nArg);
      break;
    }







    case P4_INT64: {
      sqlite3_snprintf(nTemp, zTemp, "%lld", *pOp->p4.pI64);
      break;
    }
    case P4_INT32: {
      sqlite3_snprintf(nTemp, zTemp, "%d", pOp->p4.i);
      break;
................................................................................
  n = (u32)pMem->n;
  if( flags & MEM_Zero ){
    n += pMem->u.nZero;
  }
  return ((n*2) + 12 + ((flags&MEM_Str)!=0));
}








/*
** Return the length of the data corresponding to the supplied serial-type.
*/
SQLITE_PRIVATE u32 sqlite3VdbeSerialTypeLen(u32 serial_type){
  if( serial_type>=12 ){
    return (serial_type-12)/2;
  }else{
    static const u8 aSize[] = { 0, 1, 2, 3, 4, 6, 8, 8, 0, 0, 0, 0 };
    return aSize[serial_type];
  }
}

/*
** If we are on an architecture with mixed-endian floating 
** points (ex: ARM7) then swap the lower 4 bytes with the 
** upper 4 bytes.  Return the result.
................................................................................
    if( serial_type==7 ){
      assert( sizeof(v)==sizeof(pMem->u.r) );
      memcpy(&v, &pMem->u.r, sizeof(v));
      swapMixedEndianFloat(v);
    }else{
      v = pMem->u.i;
    }
    len = i = sqlite3VdbeSerialTypeLen(serial_type);
    assert( i>0 );
    do{
      buf[--i] = (u8)(v&0xFF);
      v >>= 8;
    }while( i );
    return len;
  }
................................................................................
  testcase( typeRowid==5 );
  testcase( typeRowid==6 );
  testcase( typeRowid==8 );
  testcase( typeRowid==9 );
  if( unlikely(typeRowid<1 || typeRowid>9 || typeRowid==7) ){
    goto idx_rowid_corruption;
  }
  lenRowid = sqlite3VdbeSerialTypeLen(typeRowid);
  testcase( (u32)m.n==szHdr+lenRowid );
  if( unlikely((u32)m.n<szHdr+lenRowid) ){
    goto idx_rowid_corruption;
  }

  /* Fetch the integer off the end of the index record */
  sqlite3VdbeSerialGet((u8*)&m.z[m.n-lenRowid], typeRowid, &v);
................................................................................
  assert( pOp->p4type==P4_COLLSEQ );
  if( pOp->p1 ){
    sqlite3VdbeMemSetInt64(&aMem[pOp->p1], 0);
  }
  break;
}

/* Opcode: Function P1 P2 P3 P4 P5
** Synopsis: r[P3]=func(r[P2@P5])
**
** Invoke a user function (P4 is a pointer to a Function structure that
** defines the function) with P5 arguments taken from register P2 and
** successors.  The result of the function is stored in register P3.
** Register P3 must not be one of the function inputs.
**
** P1 is a 32-bit bitmask indicating whether or not each argument to the 
** function was determined to be constant at compile time. If the first
** argument was constant then bit 0 of P1 is set. This is used to determine
** whether meta data associated with a user function argument using the
** sqlite3_set_auxdata() API may be safely retained until the next
** invocation of this opcode.
**
** See also: AggStep and AggFinal
*/
























case OP_Function: {
  int i;
  Mem *pArg;
  sqlite3_context ctx;
  sqlite3_value **apVal;
  int n;


  n = pOp->p5;
  apVal = p->apArg;
  assert( apVal || n==0 );
  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
  ctx.pOut = &aMem[pOp->p3];
  memAboutToChange(p, ctx.pOut);

  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem-p->nCursor)+1) );
  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );























  pArg = &aMem[pOp->p2];







  for(i=0; i<n; i++, pArg++){
    assert( memIsValid(pArg) );
    apVal[i] = pArg;
    Deephemeralize(pArg);
    REGISTER_TRACE(pOp->p2+i, pArg);
  }

  assert( pOp->p4type==P4_FUNCDEF );
  ctx.pFunc = pOp->p4.pFunc;
  ctx.iOp = (int)(pOp - aOp);
  ctx.pVdbe = p;

  MemSetTypeFlag(ctx.pOut, MEM_Null);
  ctx.fErrorOrAux = 0;
  db->lastRowid = lastRowid;
  (*ctx.pFunc->xFunc)(&ctx, n, apVal); /* IMP: R-24505-23230 */
  lastRowid = db->lastRowid;  /* Remember rowid changes made by xFunc */

  /* If the function returned an error, throw an exception */
  if( ctx.fErrorOrAux ){
    if( ctx.isError ){
      sqlite3VdbeError(p, "%s", sqlite3_value_text(ctx.pOut));
      rc = ctx.isError;
    }
    sqlite3VdbeDeleteAuxData(p, (int)(pOp - aOp), pOp->p1);
  }

  /* Copy the result of the function into register P3 */

  sqlite3VdbeChangeEncoding(ctx.pOut, encoding);
  if( sqlite3VdbeMemTooBig(ctx.pOut) ){
    goto too_big;
  }

  REGISTER_TRACE(pOp->p3, ctx.pOut);
  UPDATE_MAX_BLOBSIZE(ctx.pOut);
  break;
}

/* Opcode: BitAnd P1 P2 P3 * *
** Synopsis:  r[P3]=r[P1]&r[P2]
**
** Take the bit-wise AND of the values in register P1 and P2 and
................................................................................

  v = 0;
  res = 0;
  pOut = out2Prerelease(p, pOp);
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  if( NEVER(pC->pCursor==0) ){
    /* The zero initialization above is all that is needed */
  }else{
    /* The next rowid or record number (different terms for the same
    ** thing) is obtained in a two-step algorithm.
    **
    ** First we attempt to find the largest existing rowid and add one
    ** to that.  But if the largest existing rowid is already the maximum
    ** positive integer, we have to fall through to the second
    ** probabilistic algorithm
................................................................................
**
** This instruction only works for indices.  The equivalent instruction
** for tables is OP_Insert.
*/
case OP_SorterInsert:       /* in2 */
case OP_IdxInsert: {        /* in2 */
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int nKey;
  const char *zKey;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( isSorter(pC)==(pOp->opcode==OP_SorterInsert) );
  pIn2 = &aMem[pOp->p2];
  assert( pIn2->flags & MEM_Blob );
  pCrsr = pC->pCursor;
  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
  assert( pCrsr!=0 );
  assert( pC->isTable==0 );
  rc = ExpandBlob(pIn2);
  if( rc==SQLITE_OK ){
    if( isSorter(pC) ){
      rc = sqlite3VdbeSorterWrite(pC, pIn2);
    }else{
      nKey = pIn2->n;
      zKey = pIn2->z;
      rc = sqlite3BtreeInsert(pCrsr, zKey, nKey, "", 0, 0, pOp->p3, 
          ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
          );
      assert( pC->deferredMoveto==0 );
      pC->cacheStatus = CACHE_STALE;
    }
  }
  break;
................................................................................
  pIn1 = &aMem[pOp->p1];
  assert( pIn1->flags&MEM_Int );
  VdbeBranchTaken(pIn1->u.i==0, 2);
  if( (pIn1->u.i++)==0 ) goto jump_to_p2;
  break;
}

/* Opcode: AggStep * P2 P3 P4 P5
** Synopsis: accum=r[P3] step(r[P2@P5])
**
** Execute the step function for an aggregate.  The
** function has P5 arguments.   P4 is a pointer to the FuncDef
** structure that specifies the function.  Use register











** P3 as the accumulator.
**
** The P5 arguments are taken from register P2 and its
** successors.






*/
case OP_AggStep: {
  int n;




















  int i;

  Mem *pMem;
  Mem *pRec;
  Mem t;
  sqlite3_context ctx;
  sqlite3_value **apVal;


  n = pOp->p5;
  assert( n>=0 );
  pRec = &aMem[pOp->p2];
  apVal = p->apArg;
  assert( apVal || n==0 );











  for(i=0; i<n; i++, pRec++){
    assert( memIsValid(pRec) );
    apVal[i] = pRec;
    memAboutToChange(p, pRec);

  }
  ctx.pFunc = pOp->p4.pFunc;
  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
  ctx.pMem = pMem = &aMem[pOp->p3];


  pMem->n++;
  sqlite3VdbeMemInit(&t, db, MEM_Null);
  ctx.pOut = &t;
  ctx.isError = 0;
  ctx.pVdbe = p;
  ctx.iOp = (int)(pOp - aOp);

  ctx.skipFlag = 0;
  (ctx.pFunc->xStep)(&ctx, n, apVal); /* IMP: R-24505-23230 */

  if( ctx.isError ){
    sqlite3VdbeError(p, "%s", sqlite3_value_text(&t));
    rc = ctx.isError;
  }




  if( ctx.skipFlag ){
    assert( pOp[-1].opcode==OP_CollSeq );
    i = pOp[-1].p1;
    if( i ) sqlite3VdbeMemSetInt64(&aMem[i], 1);
  }
  sqlite3VdbeMemRelease(&t);
  break;
}

/* Opcode: AggFinal P1 P2 * P4 *
** Synopsis: accum=r[P1] N=P2
**
** Execute the finalizer function for an aggregate.  P1 is
................................................................................
        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[0].pExpr);
      }
#endif
      if( pDef->funcFlags & SQLITE_FUNC_NEEDCOLL ){
        if( !pColl ) pColl = db->pDfltColl; 
        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
      }
      sqlite3VdbeAddOp4(v, OP_Function, constMask, r1, target,
                        (char*)pDef, P4_FUNCDEF);
      sqlite3VdbeChangeP5(v, (u8)nFarg);
      if( nFarg && constMask==0 ){
        sqlite3ReleaseTempRange(pParse, r1, nFarg);
      }
      break;
    }
................................................................................
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
  sqlite3VdbeAddOp2(v, OP_Integer, iParam, regStat4+1);
#elif SQLITE_DEBUG
  assert( iParam==STAT_GET_STAT1 );
#else
  UNUSED_PARAMETER( iParam );
#endif
  sqlite3VdbeAddOp3(v, OP_Function, 0, regStat4, regOut);
  sqlite3VdbeChangeP4(v, -1, (char*)&statGetFuncdef, P4_FUNCDEF);
  sqlite3VdbeChangeP5(v, 1 + IsStat34);
}

/*
** Generate code to do an analysis of all indices associated with
** a single table.
................................................................................
    ** The third argument is only used for STAT3 and STAT4
    */
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
    sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat4+3);
#endif
    sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat4+1);
    sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regStat4+2);
    sqlite3VdbeAddOp3(v, OP_Function, 0, regStat4+1, regStat4);
    sqlite3VdbeChangeP4(v, -1, (char*)&statInitFuncdef, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, 2+IsStat34);

    /* Implementation of the following:
    **
    **   Rewind csr
    **   if eof(csr) goto end_of_scan;
................................................................................
        VdbeComment((v, "%s", pTab->aCol[pPk->aiColumn[j]].zName));
      }
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regKey, pPk->nKeyCol, regRowid);
      sqlite3ReleaseTempRange(pParse, regKey, pPk->nKeyCol);
    }
#endif
    assert( regChng==(regStat4+1) );
    sqlite3VdbeAddOp3(v, OP_Function, 1, regStat4, regTemp);
    sqlite3VdbeChangeP4(v, -1, (char*)&statPushFuncdef, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, 2+IsStat34);
    sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);

    /* Add the entry to the stat1 table. */
    callStatGet(v, regStat4, STAT_GET_STAT1, regStat1);
    assert( "BBB"[0]==SQLITE_AFF_TEXT );
................................................................................
  regArgs = sqlite3GetTempRange(pParse, 4);
  sqlite3ExprCode(pParse, pFilename, regArgs);
  sqlite3ExprCode(pParse, pDbname, regArgs+1);
  sqlite3ExprCode(pParse, pKey, regArgs+2);

  assert( v || db->mallocFailed );
  if( v ){
    sqlite3VdbeAddOp3(v, OP_Function, 0, regArgs+3-pFunc->nArg, regArgs+3);
    assert( pFunc->nArg==-1 || (pFunc->nArg&0xff)==pFunc->nArg );
    sqlite3VdbeChangeP5(v, (u8)(pFunc->nArg));
    sqlite3VdbeChangeP4(v, -1, (char *)pFunc, P4_FUNCDEF);

    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
    ** statement only). For DETACH, set it to false (expire all existing
    ** statements).
................................................................................
      }
      if( !pColl ){
        pColl = pParse->db->pDfltColl;
      }
      if( regHit==0 && pAggInfo->nAccumulator ) regHit = ++pParse->nMem;
      sqlite3VdbeAddOp4(v, OP_CollSeq, regHit, 0, 0, (char *)pColl, P4_COLLSEQ);
    }
    sqlite3VdbeAddOp4(v, OP_AggStep, 0, regAgg, pF->iMem,
                      (void*)pF->pFunc, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, (u8)nArg);
    sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
    sqlite3ReleaseTempRange(pParse, regAgg, nArg);
    if( addrNext ){
      sqlite3VdbeResolveLabel(v, addrNext);
      sqlite3ExprCacheClear(pParse);
................................................................................
** the offset of the method to call in the sqlite3_module structure.
**
** The array is cleared after invoking the callbacks. 
*/
static void callFinaliser(sqlite3 *db, int offset){
  int i;
  if( db->aVTrans ){


    for(i=0; i<db->nVTrans; i++){
      VTable *pVTab = db->aVTrans[i];
      sqlite3_vtab *p = pVTab->pVtab;
      if( p ){
        int (*x)(sqlite3_vtab *);
        x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset);
        if( x ) x(p);
      }
      pVTab->iSavepoint = 0;
      sqlite3VtabUnlock(pVTab);
    }
    sqlite3DbFree(db, db->aVTrans);
    db->nVTrans = 0;
    db->aVTrans = 0;
  }
}

/*
** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans
** array. Return the error code for the first error that occurs, or
** SQLITE_OK if all xSync operations are successful.
................................................................................
*/
static int yy_pop_parser_stack(yyParser *pParser){
  YYCODETYPE yymajor;
  yyStackEntry *yytos = &pParser->yystack[pParser->yyidx];

  /* There is no mechanism by which the parser stack can be popped below
  ** empty in SQLite.  */
  if( NEVER(pParser->yyidx<0) ) return 0;
#ifndef NDEBUG
  if( yyTraceFILE && pParser->yyidx>=0 ){
    fprintf(yyTraceFILE,"%sPopping %s\n",
      yyTracePrompt,
      yyTokenName[yytos->major]);
  }
#endif
................................................................................
  zSql8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zSql8 ){
    rc = sqlite3_complete(zSql8);
  }else{
    rc = SQLITE_NOMEM;
  }
  sqlite3ValueFree(pVal);
  return sqlite3ApiExit(0, rc);
}
#endif /* SQLITE_OMIT_UTF16 */
#endif /* SQLITE_OMIT_COMPLETE */

/************** End of complete.c ********************************************/
/************** Begin file main.c ********************************************/
/*
................................................................................
#ifdef SQLITE_ENABLE_SQLLOG
  if( sqlite3GlobalConfig.xSqllog ){
    /* Opening a db handle. Fourth parameter is passed 0. */
    void *pArg = sqlite3GlobalConfig.pSqllogArg;
    sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
  }
#endif
  return sqlite3ApiExit(0, rc);
}

/*
** Open a new database handle.
*/
SQLITE_API int SQLITE_STDCALL sqlite3_open(
  const char *zFilename, 
................................................................................
      SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
    }
  }else{
    rc = SQLITE_NOMEM;
  }
  sqlite3ValueFree(pVal);

  return sqlite3ApiExit(0, rc);
}
#endif /* SQLITE_OMIT_UTF16 */

/*
** Register a new collation sequence with the database handle db.
*/
SQLITE_API int SQLITE_STDCALL sqlite3_create_collation(
................................................................................
** File control method. For custom operations on an otaVfs-file.
*/
static int otaVfsFileControl(sqlite3_file *pFile, int op, void *pArg){
  ota_file *p = (ota_file *)pFile;
  int (*xControl)(sqlite3_file*,int,void*) = p->pReal->pMethods->xFileControl;
  int rc;

  assert( p->openFlags & 
      (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB|SQLITE_OPEN_TRANSIENT_DB) 
  );
  if( op==SQLITE_FCNTL_OTA ){
    sqlite3ota *pOta = (sqlite3ota*)pArg;

    /* First try to find another OTA vfs lower down in the vfs stack. If
    ** one is found, this vfs will operate in pass-through mode. The lower
    ** level vfs will do the special OTA handling.  */

#ifndef SQLITE_DISABLE_LFS
# define _LARGE_FILE       1
# ifndef _FILE_OFFSET_BITS
#   define _FILE_OFFSET_BITS 64
# endif
# define _LARGEFILE_SOURCE 1
#endif

/* What version of GCC is being used.  0 means GCC is not being used */
#ifdef __GNUC__
# define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__)
#else
# define GCC_VERSION 0
#endif

/* Needed for various definitions... */
#if defined(__GNUC__) && !defined(_GNU_SOURCE)
# define _GNU_SOURCE
#endif

#if defined(__OpenBSD__) && !defined(_BSD_SOURCE)
................................................................................
**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.8.11"
#define SQLITE_VERSION_NUMBER 3008011
#define SQLITE_SOURCE_ID      "2015-06-30 17:28:40 fe144dd73f7097a17c24c7812c2a1cc40466e6da"

/*
** 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
................................................................................
#  define SQLITE_NOINLINE  __attribute__((noinline))
#elif defined(_MSC_VER) && _MSC_VER>=1310
#  define SQLITE_NOINLINE  __declspec(noinline)
#else
#  define SQLITE_NOINLINE
#endif

/*
** Make sure that the compiler intrinsics we desire are enabled when
** compiling with an appropriate version of MSVC.
*/
#if defined(_MSC_VER) && _MSC_VER>=1300
#  include <intrin.h>
#  pragma intrinsic(_byteswap_ushort)
#  pragma intrinsic(_byteswap_ulong)
#endif

/*
** The SQLITE_THREADSAFE macro must be defined as 0, 1, or 2.
** 0 means mutexes are permanently disable and the library is never
** threadsafe.  1 means the library is serialized which is the highest
** level of threadsafety.  2 means the library is multithreaded - multiple
** threads can use SQLite as long as no two threads try to use the same
** database connection at the same time.
................................................................................
  u8 opcode;          /* What operation to perform */
  signed char p4type; /* One of the P4_xxx constants for p4 */
  u8 opflags;         /* Mask of the OPFLG_* flags in opcodes.h */
  u8 p5;              /* Fifth parameter is an unsigned character */
  int p1;             /* First operand */
  int p2;             /* Second parameter (often the jump destination) */
  int p3;             /* The third parameter */
  union p4union {     /* fourth parameter */
    int i;                 /* Integer value if p4type==P4_INT32 */
    void *p;               /* Generic pointer */
    char *z;               /* Pointer to data for string (char array) types */
    i64 *pI64;             /* Used when p4type is P4_INT64 */
    double *pReal;         /* Used when p4type is P4_REAL */
    FuncDef *pFunc;        /* Used when p4type is P4_FUNCDEF */
    sqlite3_context *pCtx; /* Used when p4type is P4_FUNCCTX */
    CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
    Mem *pMem;             /* Used when p4type is P4_MEM */
    VTable *pVtab;         /* Used when p4type is P4_VTAB */
    KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
    int *ai;               /* Used when p4type is P4_INTARRAY */
    SubProgram *pProgram;  /* Used when p4type is P4_SUBPROGRAM */
    int (*xAdvance)(BtCursor *, int *);
................................................................................
#define P4_MPRINTF  (-11) /* P4 is a string obtained from sqlite3_mprintf() */
#define P4_REAL     (-12) /* P4 is a 64-bit floating point value */
#define P4_INT64    (-13) /* P4 is a 64-bit signed integer */
#define P4_INT32    (-14) /* P4 is a 32-bit signed integer */
#define P4_INTARRAY (-15) /* P4 is a vector of 32-bit integers */
#define P4_SUBPROGRAM  (-18) /* P4 is a pointer to a SubProgram structure */
#define P4_ADVANCE  (-19) /* P4 is a pointer to BtreeNext() or BtreePrev() */
#define P4_FUNCCTX  (-20) /* P4 is a pointer to an sqlite3_context object */

/* Error message codes for OP_Halt */
#define P5_ConstraintNotNull 1
#define P5_ConstraintUnique  2
#define P5_ConstraintCheck   3
#define P5_ConstraintFK      4

................................................................................
** The makefile scans the vdbe.c source file and creates the "opcodes.h"
** header file that defines a number for each opcode used by the VDBE.
*/
/************** Include opcodes.h in the middle of vdbe.h ********************/
/************** Begin file opcodes.h *****************************************/
/* Automatically generated.  Do not edit */
/* See the mkopcodeh.awk script for details */

#define OP_Savepoint       1
#define OP_AutoCommit      2
#define OP_Transaction     3
#define OP_SorterNext      4
#define OP_PrevIfOpen      5
#define OP_NextIfOpen      6
#define OP_Prev            7
#define OP_Next            8

#define OP_Checkpoint      9
#define OP_JournalMode    10
#define OP_Vacuum         11
#define OP_VFilter        12 /* synopsis: iplan=r[P3] zplan='P4'           */
#define OP_VUpdate        13 /* synopsis: data=r[P3@P2]                    */
#define OP_Goto           14
#define OP_Gosub          15
#define OP_Return         16

#define OP_InitCoroutine  17
#define OP_EndCoroutine   18
#define OP_Not            19 /* same as TK_NOT, synopsis: r[P2]= !r[P1]    */
#define OP_Yield          20
#define OP_HaltIfNull     21 /* synopsis: if r[P3]=null halt               */
#define OP_Halt           22
#define OP_Integer        23 /* synopsis: r[P2]=P1                         */
#define OP_Int64          24 /* synopsis: r[P2]=P4                         */
#define OP_String         25 /* synopsis: r[P2]='P4' (len=P1)              */
#define OP_Null           26 /* synopsis: r[P2..P3]=NULL                   */
#define OP_SoftNull       27 /* synopsis: r[P1]=NULL                       */
#define OP_Blob           28 /* synopsis: r[P2]=P4 (len=P1)                */
#define OP_Variable       29 /* synopsis: r[P2]=parameter(P1,P4)           */
#define OP_Move           30 /* synopsis: r[P2@P3]=r[P1@P3]                */
#define OP_Copy           31 /* synopsis: r[P2@P3+1]=r[P1@P3+1]            */
#define OP_SCopy          32 /* synopsis: r[P2]=r[P1]                      */
#define OP_ResultRow      33 /* synopsis: output=r[P1@P2]                  */
#define OP_CollSeq        34
#define OP_Function0      35 /* synopsis: r[P3]=func(r[P2@P5])             */
#define OP_Function       36 /* synopsis: r[P3]=func(r[P2@P5])             */
#define OP_AddImm         37 /* synopsis: r[P1]=r[P1]+P2                   */
#define OP_MustBeInt      38
#define OP_RealAffinity   39
#define OP_Cast           40 /* synopsis: affinity(r[P1])                  */
#define OP_Permutation    41
#define OP_Compare        42 /* synopsis: r[P1@P3] <-> r[P2@P3]            */
#define OP_Jump           43
................................................................................
#define OP_FkIfZero      136 /* synopsis: if fkctr[P1]==0 goto P2          */
#define OP_MemMax        137 /* synopsis: r[P1]=max(r[P1],r[P2])           */
#define OP_IfPos         138 /* synopsis: if r[P1]>0 goto P2               */
#define OP_IfNeg         139 /* synopsis: r[P1]+=P3, if r[P1]<0 goto P2    */
#define OP_IfNotZero     140 /* synopsis: if r[P1]!=0 then r[P1]+=P3, goto P2 */
#define OP_DecrJumpZero  141 /* synopsis: if (--r[P1])==0 goto P2          */
#define OP_JumpZeroIncr  142 /* synopsis: if (r[P1]++)==0 ) goto P2        */
#define OP_AggStep0      143 /* synopsis: accum=r[P3] step(r[P2@P5])       */
#define OP_AggStep       144 /* synopsis: accum=r[P3] step(r[P2@P5])       */
#define OP_AggFinal      145 /* synopsis: accum=r[P1] N=P2                 */
#define OP_IncrVacuum    146
#define OP_Expire        147
#define OP_TableLock     148 /* synopsis: iDb=P1 root=P2 write=P3          */
#define OP_VBegin        149
#define OP_VCreate       150
#define OP_VDestroy      151
#define OP_VOpen         152
#define OP_VColumn       153 /* synopsis: r[P3]=vcolumn(P2)                */
#define OP_VNext         154
#define OP_VRename       155
#define OP_Pagecount     156
#define OP_MaxPgcnt      157
#define OP_Init          158 /* synopsis: Start at P2                      */
#define OP_Noop          159
#define OP_Explain       160


/* Properties such as "out2" or "jump" that are specified in
** comments following the "case" for each opcode in the vdbe.c
** are encoded into bitvectors as follows:
*/
#define OPFLG_JUMP            0x0001  /* jump:  P2 holds jmp target */
#define OPFLG_IN1             0x0002  /* in1:   P1 is an input */
#define OPFLG_IN2             0x0004  /* in2:   P2 is an input */
#define OPFLG_IN3             0x0008  /* in3:   P3 is an input */
#define OPFLG_OUT2            0x0010  /* out2:  P2 is an output */
#define OPFLG_OUT3            0x0020  /* out3:  P3 is an output */
#define OPFLG_INITIALIZER {\
/*   0 */ 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01,\
/*   8 */ 0x01, 0x00, 0x10, 0x00, 0x01, 0x00, 0x01, 0x01,\
/*  16 */ 0x02, 0x01, 0x02, 0x12, 0x03, 0x08, 0x00, 0x10,\
/*  24 */ 0x10, 0x10, 0x10, 0x00, 0x10, 0x10, 0x00, 0x00,\
/*  32 */ 0x10, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x02,\
/*  40 */ 0x02, 0x00, 0x00, 0x01, 0x01, 0x03, 0x03, 0x00,\
/*  48 */ 0x00, 0x00, 0x10, 0x10, 0x08, 0x00, 0x00, 0x00,\
/*  56 */ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x09,\
/*  64 */ 0x09, 0x09, 0x09, 0x04, 0x09, 0x09, 0x09, 0x26,\
/*  72 */ 0x26, 0x09, 0x10, 0x10, 0x03, 0x03, 0x0b, 0x0b,\
/*  80 */ 0x0b, 0x0b, 0x0b, 0x0b, 0x00, 0x26, 0x26, 0x26,\
/*  88 */ 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x26, 0x00,\
/*  96 */ 0x12, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,\
/* 104 */ 0x10, 0x00, 0x01, 0x01, 0x01, 0x01, 0x04, 0x04,\
/* 112 */ 0x00, 0x10, 0x01, 0x01, 0x01, 0x01, 0x10, 0x00,\
/* 120 */ 0x00, 0x10, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00,\
/* 128 */ 0x00, 0x06, 0x23, 0x0b, 0x01, 0x10, 0x10, 0x00,\
/* 136 */ 0x01, 0x04, 0x03, 0x03, 0x03, 0x03, 0x03, 0x00,\
/* 144 */ 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,\
/* 152 */ 0x00, 0x00, 0x01, 0x00, 0x10, 0x10, 0x01, 0x00,\
/* 160 */ 0x00,}

/************** End of opcodes.h *********************************************/
/************** Continuing where we left off in vdbe.h ***********************/

/*
** Prototypes for the VDBE interface.  See comments on the implementation
** for a description of what each of these routines does.
................................................................................
  PCache *pCache;                /* Cache that owns this page */

  PgHdr *pDirtyNext;             /* Next element in list of dirty pages */
  PgHdr *pDirtyPrev;             /* Previous element in list of dirty pages */
};

/* Bit values for PgHdr.flags */
#define PGHDR_CLEAN           0x001  /* Page not on the PCache.pDirty list */
#define PGHDR_DIRTY           0x002  /* Page is on the PCache.pDirty list */
#define PGHDR_WRITEABLE       0x004  /* Journaled and ready to modify */
#define PGHDR_NEED_SYNC       0x008  /* Fsync the rollback journal before
                                     ** writing this page to the database */
#define PGHDR_NEED_READ       0x010  /* Content is unread */

#define PGHDR_DONT_WRITE      0x020  /* Do not write content to disk */

#define PGHDR_MMAP            0x040  /* This is an mmap page object */

/* Initialize and shutdown the page cache subsystem */
SQLITE_PRIVATE int sqlite3PcacheInitialize(void);
SQLITE_PRIVATE void sqlite3PcacheShutdown(void);

/* Page cache buffer management:
** These routines implement SQLITE_CONFIG_PAGECACHE.
................................................................................
# define sqlite3FaultSim(X) SQLITE_OK
#else
SQLITE_PRIVATE   int sqlite3FaultSim(int);
#endif

SQLITE_PRIVATE Bitvec *sqlite3BitvecCreate(u32);
SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec*, u32);
SQLITE_PRIVATE int sqlite3BitvecTestNotNull(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*);
#ifndef SQLITE_OMIT_BUILTIN_TEST
SQLITE_PRIVATE int sqlite3BitvecBuiltinTest(int,int*);
#endif
................................................................................
** But this file is the only place where the internal details of this
** structure are known.
**
** This structure is defined inside of vdbeInt.h because it uses substructures
** (Mem) which are only defined there.
*/
struct sqlite3_context {
  Mem *pOut;              /* The return value is stored here */
  FuncDef *pFunc;         /* Pointer to function information */
  Mem *pMem;              /* Memory cell used to store aggregate context */
  Vdbe *pVdbe;            /* The VM that owns this context */
  int iOp;                /* Instruction number of OP_Function */
  int isError;            /* Error code returned by the function. */
  u8 skipFlag;            /* Skip accumulator loading if true */
  u8 fErrorOrAux;         /* isError!=0 or pVdbe->pAuxData modified */
  u8 argc;                /* Number of arguments */
  sqlite3_value *argv[1]; /* Argument set */
};

/*
** An Explain object accumulates indented output which is helpful
** in describing recursive data structures.
*/
struct Explain {
................................................................................
** returning control to the user) that has called sqlite3_malloc or
** sqlite3_realloc.
**
** The returned value is normally a copy of the second argument to this
** function. However, if a malloc() failure has occurred since the previous
** invocation SQLITE_NOMEM is returned instead. 
**
** If an OOM as occurred, then the connection error-code (the value
** returned by sqlite3_errcode()) is set to SQLITE_NOMEM.

*/
SQLITE_PRIVATE int sqlite3ApiExit(sqlite3* db, int rc){
  /* If the db handle must hold the connection handle mutex here.
  ** Otherwise the read (and possible write) of db->mallocFailed 
  ** is unsafe, as is the call to sqlite3Error().
  */
  assert( db!=0 );
  assert( sqlite3_mutex_held(db->mutex) );

  if( db->mallocFailed || rc==SQLITE_IOERR_NOMEM ){
    return apiOomError(db);
  }
  return rc & db->errMask;
}

/************** End of malloc.c **********************************************/
................................................................................
** lower 30 bits of a 32-bit signed integer.
**
** The value returned will never be negative.  Nor will it ever be greater
** than the actual length of the string.  For very long strings (greater
** than 1GiB) the value returned might be less than the true string length.
*/
SQLITE_PRIVATE int sqlite3Strlen30(const char *z){

  if( z==0 ) return 0;

  return 0x3fffffff & (int)strlen(z);
}

/*
** Set the current error code to err_code and clear any prior error message.
*/
SQLITE_PRIVATE void sqlite3Error(sqlite3 *db, int err_code){
  assert( db!=0 );
................................................................................
}


/*
** Read or write a four-byte big-endian integer value.
*/
SQLITE_PRIVATE u32 sqlite3Get4byte(const u8 *p){
#if SQLITE_BYTEORDER==4321
  u32 x;
  memcpy(&x,p,4);
  return x;
#elif SQLITE_BYTEORDER==1234 && defined(__GNUC__)
  u32 x;
  memcpy(&x,p,4);
  return __builtin_bswap32(x);
#elif SQLITE_BYTEORDER==1234 && defined(_MSC_VER) && _MSC_VER>=1300
  u32 x;
  memcpy(&x,p,4);
  return _byteswap_ulong(x);
#else
  testcase( p[0]&0x80 );
  return ((unsigned)p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
#endif
}
SQLITE_PRIVATE void sqlite3Put4byte(unsigned char *p, u32 v){
#if SQLITE_BYTEORDER==4321
  memcpy(p,&v,4);
#elif SQLITE_BYTEORDER==1234 && defined(__GNUC__)
  u32 x = __builtin_bswap32(v);
  memcpy(p,&x,4);
#elif SQLITE_BYTEORDER==1234 && defined(_MSC_VER) && _MSC_VER>=1300
  u32 x = _byteswap_ulong(v);
  memcpy(p,&x,4);
#else
  p[0] = (u8)(v>>24);
  p[1] = (u8)(v>>16);
  p[2] = (u8)(v>>8);
  p[3] = (u8)v;
#endif
}



/*
** Translate a single byte of Hex into an integer.
** This routine only works if h really is a valid hexadecimal
................................................................................
#if defined(SQLITE_ENABLE_EXPLAIN_COMMENTS) || defined(SQLITE_DEBUG)
# define OpHelp(X) "\0" X
#else
# define OpHelp(X)
#endif
SQLITE_PRIVATE const char *sqlite3OpcodeName(int i){
 static const char *const azName[] = { "?",

     /*   1 */ "Savepoint"        OpHelp(""),
     /*   2 */ "AutoCommit"       OpHelp(""),
     /*   3 */ "Transaction"      OpHelp(""),
     /*   4 */ "SorterNext"       OpHelp(""),
     /*   5 */ "PrevIfOpen"       OpHelp(""),
     /*   6 */ "NextIfOpen"       OpHelp(""),
     /*   7 */ "Prev"             OpHelp(""),
     /*   8 */ "Next"             OpHelp(""),

     /*   9 */ "Checkpoint"       OpHelp(""),
     /*  10 */ "JournalMode"      OpHelp(""),
     /*  11 */ "Vacuum"           OpHelp(""),
     /*  12 */ "VFilter"          OpHelp("iplan=r[P3] zplan='P4'"),
     /*  13 */ "VUpdate"          OpHelp("data=r[P3@P2]"),
     /*  14 */ "Goto"             OpHelp(""),
     /*  15 */ "Gosub"            OpHelp(""),
     /*  16 */ "Return"           OpHelp(""),

     /*  17 */ "InitCoroutine"    OpHelp(""),
     /*  18 */ "EndCoroutine"     OpHelp(""),
     /*  19 */ "Not"              OpHelp("r[P2]= !r[P1]"),
     /*  20 */ "Yield"            OpHelp(""),
     /*  21 */ "HaltIfNull"       OpHelp("if r[P3]=null halt"),
     /*  22 */ "Halt"             OpHelp(""),
     /*  23 */ "Integer"          OpHelp("r[P2]=P1"),
     /*  24 */ "Int64"            OpHelp("r[P2]=P4"),
     /*  25 */ "String"           OpHelp("r[P2]='P4' (len=P1)"),
     /*  26 */ "Null"             OpHelp("r[P2..P3]=NULL"),
     /*  27 */ "SoftNull"         OpHelp("r[P1]=NULL"),
     /*  28 */ "Blob"             OpHelp("r[P2]=P4 (len=P1)"),
     /*  29 */ "Variable"         OpHelp("r[P2]=parameter(P1,P4)"),
     /*  30 */ "Move"             OpHelp("r[P2@P3]=r[P1@P3]"),
     /*  31 */ "Copy"             OpHelp("r[P2@P3+1]=r[P1@P3+1]"),
     /*  32 */ "SCopy"            OpHelp("r[P2]=r[P1]"),
     /*  33 */ "ResultRow"        OpHelp("output=r[P1@P2]"),
     /*  34 */ "CollSeq"          OpHelp(""),
     /*  35 */ "Function0"        OpHelp("r[P3]=func(r[P2@P5])"),
     /*  36 */ "Function"         OpHelp("r[P3]=func(r[P2@P5])"),
     /*  37 */ "AddImm"           OpHelp("r[P1]=r[P1]+P2"),
     /*  38 */ "MustBeInt"        OpHelp(""),
     /*  39 */ "RealAffinity"     OpHelp(""),
     /*  40 */ "Cast"             OpHelp("affinity(r[P1])"),
     /*  41 */ "Permutation"      OpHelp(""),
     /*  42 */ "Compare"          OpHelp("r[P1@P3] <-> r[P2@P3]"),
     /*  43 */ "Jump"             OpHelp(""),
................................................................................
     /* 136 */ "FkIfZero"         OpHelp("if fkctr[P1]==0 goto P2"),
     /* 137 */ "MemMax"           OpHelp("r[P1]=max(r[P1],r[P2])"),
     /* 138 */ "IfPos"            OpHelp("if r[P1]>0 goto P2"),
     /* 139 */ "IfNeg"            OpHelp("r[P1]+=P3, if r[P1]<0 goto P2"),
     /* 140 */ "IfNotZero"        OpHelp("if r[P1]!=0 then r[P1]+=P3, goto P2"),
     /* 141 */ "DecrJumpZero"     OpHelp("if (--r[P1])==0 goto P2"),
     /* 142 */ "JumpZeroIncr"     OpHelp("if (r[P1]++)==0 ) goto P2"),
     /* 143 */ "AggStep0"         OpHelp("accum=r[P3] step(r[P2@P5])"),
     /* 144 */ "AggStep"          OpHelp("accum=r[P3] step(r[P2@P5])"),
     /* 145 */ "AggFinal"         OpHelp("accum=r[P1] N=P2"),
     /* 146 */ "IncrVacuum"       OpHelp(""),
     /* 147 */ "Expire"           OpHelp(""),
     /* 148 */ "TableLock"        OpHelp("iDb=P1 root=P2 write=P3"),
     /* 149 */ "VBegin"           OpHelp(""),
     /* 150 */ "VCreate"          OpHelp(""),
     /* 151 */ "VDestroy"         OpHelp(""),
     /* 152 */ "VOpen"            OpHelp(""),
     /* 153 */ "VColumn"          OpHelp("r[P3]=vcolumn(P2)"),
     /* 154 */ "VNext"            OpHelp(""),
     /* 155 */ "VRename"          OpHelp(""),
     /* 156 */ "Pagecount"        OpHelp(""),
     /* 157 */ "MaxPgcnt"         OpHelp(""),
     /* 158 */ "Init"             OpHelp("Start at P2"),
     /* 159 */ "Noop"             OpHelp(""),
     /* 160 */ "Explain"          OpHelp(""),
  };
  return azName[i];
}
#endif

/************** End of opcodes.c *********************************************/
/************** Begin file os_unix.c *****************************************/
................................................................................
}

/*
** Check to see if the i-th bit is set.  Return true or false.
** If p is NULL (if the bitmap has not been created) or if
** i is out of range, then return false.
*/
SQLITE_PRIVATE int sqlite3BitvecTestNotNull(Bitvec *p, u32 i){
  assert( p!=0 );

  i--;
  if( i>=p->iSize ) return 0;
  while( p->iDivisor ){
    u32 bin = i/p->iDivisor;
    i = i%p->iDivisor;
    p = p->u.apSub[bin];
    if (!p) {
      return 0;
    }
................................................................................
    u32 h = BITVEC_HASH(i++);
    while( p->u.aHash[h] ){
      if( p->u.aHash[h]==i ) return 1;
      h = (h+1) % BITVEC_NINT;
    }
    return 0;
  }
}
SQLITE_PRIVATE int sqlite3BitvecTest(Bitvec *p, u32 i){
  return p!=0 && sqlite3BitvecTestNotNull(p,i);
}

/*
** Set the i-th bit.  Return 0 on success and an error code if
** anything goes wrong.
**
** This routine might cause sub-bitmaps to be allocated.  Failing
................................................................................
  Pgno pgno,                  /* Page number obtained */
  sqlite3_pcache_page *pPage  /* Page obtained by prior PcacheFetch() call */
){
  PgHdr *pPgHdr;
  assert( pPage!=0 );
  pPgHdr = (PgHdr*)pPage->pExtra;
  assert( pPgHdr->pPage==0 );
  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;
  pPgHdr->flags = PGHDR_CLEAN;
  return sqlite3PcacheFetchFinish(pCache,pgno,pPage);
}

/*
** This routine converts the sqlite3_pcache_page object returned by
** sqlite3PcacheFetch() into an initialized PgHdr object.  This routine
** must be called after sqlite3PcacheFetch() in order to get a usable
................................................................................
SQLITE_PRIVATE PgHdr *sqlite3PcacheFetchFinish(
  PCache *pCache,             /* Obtain the page from this cache */
  Pgno pgno,                  /* Page number obtained */
  sqlite3_pcache_page *pPage  /* Page obtained by prior PcacheFetch() call */
){
  PgHdr *pPgHdr;

  assert( pPage!=0 );
  pPgHdr = (PgHdr *)pPage->pExtra;

  if( !pPgHdr->pPage ){
    return pcacheFetchFinishWithInit(pCache, pgno, pPage);
  }
  if( 0==pPgHdr->nRef ){
    pCache->nRef++;
................................................................................
** reference count drops to 0, then it is made eligible for recycling.
*/
SQLITE_PRIVATE void SQLITE_NOINLINE sqlite3PcacheRelease(PgHdr *p){
  assert( p->nRef>0 );
  p->nRef--;
  if( p->nRef==0 ){
    p->pCache->nRef--;
    if( p->flags&PGHDR_CLEAN ){
      pcacheUnpin(p);
    }else if( p->pDirtyPrev!=0 ){
      /* Move the page to the head of the dirty list. */
      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_FRONT);
    }
  }
}
................................................................................
}

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

  assert( p->nRef>0 );
  if( p->flags & (PGHDR_CLEAN|PGHDR_DONT_WRITE) ){
    p->flags &= ~PGHDR_DONT_WRITE;
    if( p->flags & PGHDR_CLEAN ){
      p->flags ^= (PGHDR_DIRTY|PGHDR_CLEAN);
      assert( (p->flags & (PGHDR_DIRTY|PGHDR_CLEAN))==PGHDR_DIRTY );
      pcacheManageDirtyList(p, PCACHE_DIRTYLIST_ADD);
    }
  }
}

/*
** Make sure the page is marked as clean. If it isn't clean already,
** make it so.
*/
SQLITE_PRIVATE void sqlite3PcacheMakeClean(PgHdr *p){
  if( (p->flags & PGHDR_DIRTY) ){
    assert( (p->flags & PGHDR_CLEAN)==0 );
    pcacheManageDirtyList(p, PCACHE_DIRTYLIST_REMOVE);
    p->flags &= ~(PGHDR_DIRTY|PGHDR_NEED_SYNC|PGHDR_WRITEABLE);
    p->flags |= PGHDR_CLEAN;
    if( p->nRef==0 ){
      pcacheUnpin(p);
    }
  }
}

/*
................................................................................
  return pPage;
}


/*
** Remove the page supplied as an argument from the hash table 
** (PCache1.apHash structure) that it is currently stored in.
** Also free the page if freePage is true.
**
** The PGroup mutex must be held when this function is called.
*/
static void pcache1RemoveFromHash(PgHdr1 *pPage, int freeFlag){
  unsigned int h;
  PCache1 *pCache = pPage->pCache;
  PgHdr1 **pp;

  assert( sqlite3_mutex_held(pCache->pGroup->mutex) );
  h = pPage->iKey % pCache->nHash;
  for(pp=&pCache->apHash[h]; (*pp)!=pPage; pp=&(*pp)->pNext);
  *pp = (*pp)->pNext;

  pCache->nPage--;
  if( freeFlag ) pcache1FreePage(pPage);
}

/*
** If there are currently more than nMaxPage pages allocated, try
** to recycle pages to reduce the number allocated to nMaxPage.
*/
static void pcache1EnforceMaxPage(PGroup *pGroup){
  assert( sqlite3_mutex_held(pGroup->mutex) );
  while( pGroup->nCurrentPage>pGroup->nMaxPage && pGroup->pLruTail ){
    PgHdr1 *p = pGroup->pLruTail;
    assert( p->pCache->pGroup==pGroup );
    assert( p->isPinned==0 );
    pcache1PinPage(p);
    pcache1RemoveFromHash(p, 1);

  }
}

/*
** Discard all pages from cache pCache with a page number (key value) 
** greater than or equal to iLimit. Any pinned pages that meet this 
** criteria are unpinned before they are discarded.
................................................................................
         (pCache->nPage+1>=pCache->nMax)
      || pGroup->nCurrentPage>=pGroup->nMaxPage
      || pcache1UnderMemoryPressure(pCache)
  )){
    PCache1 *pOther;
    pPage = pGroup->pLruTail;
    assert( pPage->isPinned==0 );
    pcache1RemoveFromHash(pPage, 0);
    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 );
................................................................................
  ** part of the PGroup LRU list.
  */
  assert( pPage->pLruPrev==0 && pPage->pLruNext==0 );
  assert( pGroup->pLruHead!=pPage && pGroup->pLruTail!=pPage );
  assert( pPage->isPinned==1 );

  if( reuseUnlikely || pGroup->nCurrentPage>pGroup->nMaxPage ){
    pcache1RemoveFromHash(pPage, 1);

  }else{
    /* Add the page to the PGroup LRU list. */
    if( pGroup->pLruHead ){
      pGroup->pLruHead->pLruPrev = pPage;
      pPage->pLruNext = pGroup->pLruHead;
      pGroup->pLruHead = pPage;
    }else{
................................................................................
    while( (nReq<0 || nFree<nReq) && ((p=pcache1.grp.pLruTail)!=0) ){
      nFree += pcache1MemSize(p->page.pBuf);
#ifdef SQLITE_PCACHE_SEPARATE_HEADER
      nFree += sqlite3MemSize(p);
#endif
      assert( p->isPinned==0 );
      pcache1PinPage(p);
      pcache1RemoveFromHash(p, 1);

    }
    pcache1LeaveMutex(&pcache1.grp);
  }
  return nFree;
}
#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */

................................................................................
  u32 aWalData[WAL_SAVEPOINT_NDATA];        /* WAL savepoint context */
#endif
};

/*
** Bits of the Pager.doNotSpill flag.  See further description below.
*/
#define SPILLFLAG_OFF         0x01 /* Never spill cache.  Set via pragma */
#define SPILLFLAG_ROLLBACK    0x02 /* Current rolling back, so do not spill */
#define SPILLFLAG_NOSYNC      0x04 /* Spill is ok, but do not sync */

/*
** An open page cache is an instance of struct Pager. A description of
** some of the more important member variables follows:
**
** eState
**
................................................................................
**   writing to the database from pagerStress() is disabled altogether.
**   The SPILLFLAG_ROLLBACK case is done in a very obscure case that
**   comes up during savepoint rollback that requires the pcache module
**   to allocate a new page to prevent the journal file from being written
**   while it is being traversed by code in pager_playback().  The SPILLFLAG_OFF
**   case is a user preference.
** 
**   If the SPILLFLAG_NOSYNC bit is set, writing to the database from
**   pagerStress() is permitted, but syncing the journal file is not.
**   This flag is set by sqlite3PagerWrite() when the file-system sector-size
**   is larger than the database page-size in order to prevent a journal sync
**   from happening in between the journalling of two pages on the same sector. 
**
** subjInMemory
**
**   This is a boolean variable. If true, then any required sub-journal
**   is opened as an in-memory journal file. If false, then in-memory
**   sub-journals are only used for in-memory pager files.
**
................................................................................
  u8 eState;                  /* Pager state (OPEN, READER, WRITER_LOCKED..) */
  u8 eLock;                   /* Current lock held on database file */
  u8 changeCountDone;         /* Set after incrementing the change-counter */
  u8 setMaster;               /* True if a m-j name has been written to jrnl */
  u8 doNotSpill;              /* Do not spill the cache when non-zero */
  u8 subjInMemory;            /* True to use in-memory sub-journals */
  u8 bUseFetch;               /* True to use xFetch() */
  u8 hasBeenUsed;             /* True if any content previously read */
  Pgno dbSize;                /* Number of pages in the database */
  Pgno dbOrigSize;            /* dbSize before the current transaction */
  Pgno dbFileSize;            /* Number of pages in the database file */
  Pgno dbHintSize;            /* Value passed to FCNTL_SIZE_HINT call */
  int errCode;                /* One of several kinds of errors */
  int nRec;                   /* Pages journalled since last j-header written */
  u32 cksumInit;              /* Quasi-random value added to every checksum */
................................................................................
**
**   if( isOpen(pPager->jfd) ){ ...
**
** instead of
**
**   if( pPager->jfd->pMethods ){ ...
*/
#define isOpen(pFd) ((pFd)->pMethods!=0)

/*
** Return true if this pager uses a write-ahead log instead of the usual
** rollback journal. Otherwise false.
*/
#ifndef SQLITE_OMIT_WAL
static int pagerUseWal(Pager *pPager){
................................................................................
static int subjRequiresPage(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  PagerSavepoint *p;
  Pgno pgno = pPg->pgno;
  int i;
  for(i=0; i<pPager->nSavepoint; i++){
    p = &pPager->aSavepoint[i];
    if( p->nOrig>=pgno && 0==sqlite3BitvecTestNotNull(p->pInSavepoint, pgno) ){
      return 1;
    }
  }
  return 0;
}

#ifdef SQLITE_DEBUG
/*
** Return true if the page is already in the journal file.
*/
static int pageInJournal(Pager *pPager, PgHdr *pPg){
  return sqlite3BitvecTest(pPager->pInJournal, pPg->pgno);
}
#endif

/*
** Read a 32-bit integer from the given file descriptor.  Store the integer
** that is read in *pRes.  Return SQLITE_OK if everything worked, or an
** error code is something goes wrong.
**
** All values are stored on disk as big-endian.
................................................................................
  /* Write the master journal data to the end of the journal file. If
  ** an error occurs, return the error code to the caller.
  */
  if( (0 != (rc = write32bits(pPager->jfd, iHdrOff, PAGER_MJ_PGNO(pPager))))
   || (0 != (rc = sqlite3OsWrite(pPager->jfd, zMaster, nMaster, iHdrOff+4)))
   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nMaster, nMaster)))
   || (0 != (rc = write32bits(pPager->jfd, iHdrOff+4+nMaster+4, cksum)))
   || (0 != (rc = sqlite3OsWrite(pPager->jfd, aJournalMagic, 8,
                                 iHdrOff+4+nMaster+8)))
  ){
    return rc;
  }
  pPager->journalOff += (nMaster+20);

  /* If the pager is in peristent-journal mode, then the physical 
  ** journal-file may extend past the end of the master-journal name
................................................................................
    rc = read32bits(jfd, (*pOffset)-4, &cksum);
    if( rc ) return rc;
    if( !isSavepnt && pager_cksum(pPager, (u8*)aData)!=cksum ){
      return SQLITE_DONE;
    }
  }

  /* If this page has already been played back before during the current
  ** rollback, then don't bother to play it back again.
  */
  if( pDone && (rc = sqlite3BitvecSet(pDone, pgno))!=SQLITE_OK ){
    return rc;
  }

  /* When playing back page 1, restore the nReserve setting
................................................................................
    }
  }
  return rc;
}

/*
** Append a record of the current state of page pPg to the sub-journal. 


**
** If successful, set the bit corresponding to pPg->pgno in the bitvecs
** for all open savepoints before returning.
**
** This function returns SQLITE_OK if everything is successful, an IO
** error code if the attempt to write to the sub-journal fails, or 
** SQLITE_NOMEM if a malloc fails while setting a bit in a savepoint
................................................................................
  }
  if( rc==SQLITE_OK ){
    pPager->nSubRec++;
    assert( pPager->nSavepoint>0 );
    rc = addToSavepointBitvecs(pPager, pPg->pgno);
  }
  return rc;
}
static int subjournalPageIfRequired(PgHdr *pPg){
  if( subjRequiresPage(pPg) ){
    return subjournalPage(pPg);
  }else{
    return SQLITE_OK;
  }
}

/*
** This function is called by the pcache layer when it has reached some
** soft memory limit. The first argument is a pointer to a Pager object
** (cast as a void*). The pager is always 'purgeable' (not an in-memory
** database). The second argument is a reference to a page that is 
................................................................................
  ){
    return SQLITE_OK;
  }

  pPg->pDirty = 0;
  if( pagerUseWal(pPager) ){
    /* Write a single frame for this page to the log. */

    rc = subjournalPageIfRequired(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 = syncJournal(pPager, 1);
    }
  

































    /* Write the contents of the page out to the database file. */
    if( rc==SQLITE_OK ){
      assert( (pPg->flags&PGHDR_NEED_SYNC)==0 );
      rc = pager_write_pagelist(pPager, pPg);
    }
  }

................................................................................
    ** disk and uses an in-memory rollback journal.
    **
    ** This branch also runs for files marked as immutable.
    */ 
act_like_temp_file:
    tempFile = 1;
    pPager->eState = PAGER_READER;     /* Pretend we already have a lock */
    pPager->eLock = EXCLUSIVE_LOCK;    /* Pretend we are in EXCLUSIVE mode */
    pPager->noLock = 1;                /* Do no locking */
    readOnly = (vfsFlags&SQLITE_OPEN_READONLY);
  }

  /* The following call to PagerSetPagesize() serves to set the value of 
  ** Pager.pageSize and to allocate the Pager.pTmpSpace buffer.
  */
................................................................................
  }

  /* Initialize the PCache object. */
  if( rc==SQLITE_OK ){
    assert( nExtra<1000 );
    nExtra = ROUND8(nExtra);
    rc = sqlite3PcacheOpen(szPageDflt, nExtra, !memDb,
                       !memDb?pagerStress:0, (void *)pPager, pPager->pPCache);
  }

  /* If an error occurred above, free the  Pager structure and close the file.
  */
  if( rc!=SQLITE_OK ){
    sqlite3OsClose(pPager->fd);
    sqlite3PageFree(pPager->pTmpSpace);
................................................................................
    if( !pPager->tempFile && pPager->hasBeenUsed ){
      /* The shared-lock has just been acquired then check to
      ** see if the database has been modified.  If the database has changed,
      ** flush the cache.  The pPager->hasBeenUsed flag prevents this from
      ** occurring on the very first access to a file, in order to save a
      ** single unnecessary sqlite3OsRead() call at the start-up.
      **
      ** Database changes are detected by looking at 15 bytes beginning
      ** at offset 24 into the file.  The first 4 of these 16 bytes are
      ** a 32-bit counter that is incremented with each change.  The
      ** other bytes change randomly with each file change when
      ** a codec is in use.
      ** 
      ** There is a vanishingly small chance that a change will not be 
      ** detected.  The chance of an undetected change is so small that
................................................................................

    {
      sqlite3_pcache_page *pBase;
      pBase = sqlite3PcacheFetch(pPager->pPCache, pgno, 3);
      if( pBase==0 ){
        rc = sqlite3PcacheFetchStress(pPager->pPCache, pgno, &pBase);
        if( rc!=SQLITE_OK ) goto pager_acquire_err;
        if( pBase==0 ){
          pPg = *ppPage = 0;
          rc = SQLITE_NOMEM;
          goto pager_acquire_err;
        }
      }
      pPg = *ppPage = sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pBase);

      assert( pPg!=0 );
    }
  }

  if( rc!=SQLITE_OK ){
    /* Either the call to sqlite3PcacheFetch() returned an error or the
    ** pager was already in the error-state when this function was called.
    ** Set pPg to 0 and jump to the exception handler.  */
    pPg = 0;
    goto pager_acquire_err;
  }
  assert( pPg==(*ppPage) );
  assert( pPg->pgno==pgno );
  assert( pPg->pPager==pPager || pPg->pPager==0 );

  if( pPg->pPager && !noContent ){
    /* In this case the pcache already contains an initialized copy of
    ** the page. Return without further ado.  */
    assert( pgno<=PAGER_MAX_PGNO && pgno!=PAGER_MJ_PGNO(pPager) );
    pPager->aStat[PAGER_STAT_HIT]++;
    return SQLITE_OK;

  }else{
    /* The pager cache has created a new page. Its content needs to 
    ** be initialized.  */


    pPg->pPager = pPager;

    /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
    ** number greater than this, or the unused locking-page, is requested. */
    if( pgno>PAGER_MAX_PGNO || pgno==PAGER_MJ_PGNO(pPager) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto pager_acquire_err;
................................................................................
SQLITE_PRIVATE DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
  sqlite3_pcache_page *pPage;
  assert( pPager!=0 );
  assert( pgno!=0 );
  assert( pPager->pPCache!=0 );
  pPage = sqlite3PcacheFetch(pPager->pPCache, pgno, 0);
  assert( pPage==0 || pPager->hasBeenUsed );
  if( pPage==0 ) return 0;
  return sqlite3PcacheFetchFinish(pPager->pPCache, pgno, pPage);
}

/*
** Release a page reference.
**
** If the number of references to the page drop to zero, then the
................................................................................
    assert( rc!=SQLITE_OK || pPager->eState==PAGER_WRITER_LOCKED );
    assert( assert_pager_state(pPager) );
  }

  PAGERTRACE(("TRANSACTION %d\n", PAGERID(pPager)));
  return rc;
}

/*
** Write page pPg onto the end of the rollback journal.
*/
static SQLITE_NOINLINE int pagerAddPageToRollbackJournal(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  int rc;
  u32 cksum;
  char *pData2;
  i64 iOff = pPager->journalOff;

  /* We should never write to the journal file the page that
  ** contains the database locks.  The following assert verifies
  ** that we do not. */
  assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );

  assert( pPager->journalHdr<=pPager->journalOff );
  CODEC2(pPager, pPg->pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
  cksum = pager_cksum(pPager, (u8*)pData2);

  /* Even if an IO or diskfull error occurs while journalling the
  ** page in the block above, set the need-sync flag for the page.
  ** Otherwise, when the transaction is rolled back, the logic in
  ** playback_one_page() will think that the page needs to be restored
  ** in the database file. And if an IO error occurs while doing so,
  ** then corruption may follow.
  */
  pPg->flags |= PGHDR_NEED_SYNC;

  rc = write32bits(pPager->jfd, iOff, pPg->pgno);
  if( rc!=SQLITE_OK ) return rc;
  rc = sqlite3OsWrite(pPager->jfd, pData2, pPager->pageSize, iOff+4);
  if( rc!=SQLITE_OK ) return rc;
  rc = write32bits(pPager->jfd, iOff+pPager->pageSize+4, cksum);
  if( rc!=SQLITE_OK ) return rc;

  IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno, 
           pPager->journalOff, pPager->pageSize));
  PAGER_INCR(sqlite3_pager_writej_count);
  PAGERTRACE(("JOURNAL %d page %d needSync=%d hash(%08x)\n",
       PAGERID(pPager), pPg->pgno, 
       ((pPg->flags&PGHDR_NEED_SYNC)?1:0), pager_pagehash(pPg)));

  pPager->journalOff += 8 + pPager->pageSize;
  pPager->nRec++;
  assert( pPager->pInJournal!=0 );
  rc = sqlite3BitvecSet(pPager->pInJournal, pPg->pgno);
  testcase( rc==SQLITE_NOMEM );
  assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
  rc |= addToSavepointBitvecs(pPager, pPg->pgno);
  assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
  return rc;
}

/*
** Mark a single data page as writeable. The page is written into the 
** main journal or sub-journal as required. If the page is written into
** one of the journals, the corresponding bit is set in the 
** Pager.pInJournal bitvec and the PagerSavepoint.pInSavepoint bitvecs
** of any open savepoints as appropriate.
*/
static int pager_write(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;


  /* This routine is not called unless a write-transaction has already 
  ** been started. The journal file may or may not be open at this point.
  ** It is never called in the ERROR state.
  */
  assert( pPager->eState==PAGER_WRITER_LOCKED
       || pPager->eState==PAGER_WRITER_CACHEMOD
       || pPager->eState==PAGER_WRITER_DBMOD
  );
  assert( assert_pager_state(pPager) );
  assert( pPager->errCode==0 );
  assert( pPager->readOnly==0 );

  CHECK_PAGE(pPg);

  /* The journal file needs to be opened. Higher level routines have already
  ** obtained the necessary locks to begin the write-transaction, but the
  ** rollback journal might not yet be open. Open it now if this is the case.
  **
  ** This is done before calling sqlite3PcacheMakeDirty() on the page. 
................................................................................
  if( pPager->eState==PAGER_WRITER_LOCKED ){
    rc = pager_open_journal(pPager);
    if( rc!=SQLITE_OK ) return rc;
  }
  assert( pPager->eState>=PAGER_WRITER_CACHEMOD );
  assert( assert_pager_state(pPager) );

  /* Mark the page that is about to be modified as dirty. */


  sqlite3PcacheMakeDirty(pPg);








  /* If a rollback journal is in use, them make sure the page that is about
  ** to change is in the rollback journal, or if the page is a new page off
  ** then end of the file, make sure it is marked as PGHDR_NEED_SYNC.
  */


  assert( (pPager->pInJournal!=0) == isOpen(pPager->jfd) );






































  if( pPager->pInJournal!=0
   && sqlite3BitvecTestNotNull(pPager->pInJournal, pPg->pgno)==0



  ){
    assert( pagerUseWal(pPager)==0 );
    if( pPg->pgno<=pPager->dbOrigSize ){
      rc = pagerAddPageToRollbackJournal(pPg);
      if( rc!=SQLITE_OK ){

        return rc;
      }
    }else{
      if( pPager->eState!=PAGER_WRITER_DBMOD ){
        pPg->flags |= PGHDR_NEED_SYNC;
      }
      PAGERTRACE(("APPEND %d page %d needSync=%d\n",
              PAGERID(pPager), pPg->pgno,
             ((pPg->flags&PGHDR_NEED_SYNC)?1:0)));
    }
  }

  /* The PGHDR_DIRTY bit is set above when the page was added to the dirty-list
  ** and before writing the page into the rollback journal.  Wait until now,
  ** after the page has been successfully journalled, before setting the
  ** PGHDR_WRITEABLE bit that indicates that the page can be safely modified.
  */
  pPg->flags |= PGHDR_WRITEABLE;
  
  /* If the statement journal is open and the page is not in it,
  ** then write the page into the statement journal.


  */
  if( pPager->nSavepoint>0 ){
    rc = subjournalPageIfRequired(pPg);
  }


  /* Update the database size and return. */

  if( pPager->dbSize<pPg->pgno ){
    pPager->dbSize = pPg->pgno;
  }
  return rc;
}

/*
................................................................................
** This is a variant of sqlite3PagerWrite() that runs when the sector size
** is larger than the page size.  SQLite makes the (reasonable) assumption that
** all bytes of a sector are written together by hardware.  Hence, all bytes of
** a sector need to be journalled in case of a power loss in the middle of
** a write.
**
** Usually, the sector size is less than or equal to the page size, in which
** case pages can be individually written.  This routine only runs in the
** exceptional case where the page size is smaller than the sector size.
*/
static SQLITE_NOINLINE int pagerWriteLargeSector(PgHdr *pPg){
  int rc = SQLITE_OK;          /* Return code */
  Pgno nPageCount;             /* Total number of pages in database file */
  Pgno pg1;                    /* First page of the sector pPg is located on. */
  int nPage = 0;               /* Number of pages starting at pg1 to journal */
  int ii;                      /* Loop counter */
  int needSync = 0;            /* True if any page has PGHDR_NEED_SYNC */
  Pager *pPager = pPg->pPager; /* The pager that owns pPg */
  Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);

  /* Set the doNotSpill NOSYNC bit to 1. This is because we cannot allow
  ** a journal header to be written between the pages journaled by
  ** this function.
  */
  assert( !MEMDB );
................................................................................
** fit on a single disk sector. In this case all co-resident pages
** must have been written to the journal file before returning.
**
** If an error occurs, SQLITE_NOMEM or an IO error code is returned
** as appropriate. Otherwise, SQLITE_OK.
*/
SQLITE_PRIVATE int sqlite3PagerWrite(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  assert( (pPg->flags & PGHDR_MMAP)==0 );
  assert( pPager->eState>=PAGER_WRITER_LOCKED );
  assert( pPager->eState!=PAGER_ERROR );
  assert( assert_pager_state(pPager) );
  if( (pPg->flags & PGHDR_WRITEABLE)!=0 && pPager->dbSize>=pPg->pgno ){
    if( pPager->nSavepoint ) return subjournalPageIfRequired(pPg);
    return SQLITE_OK;
  }else if( pPager->sectorSize > (u32)pPager->pageSize ){
    return pagerWriteLargeSector(pPg);
  }else{
    return pager_write(pPg);
  }
}

/*
** Return TRUE if the page given in the argument was previously passed
** to sqlite3PagerWrite().  In other words, return TRUE if it is ok
** to change the content of the page.
*/
#ifndef NDEBUG
SQLITE_PRIVATE int sqlite3PagerIswriteable(DbPage *pPg){
  return pPg->flags & PGHDR_WRITEABLE;
}
#endif

/*
** A call to this routine tells the pager that it is not necessary to
** write the information on page pPg back to the disk, even though
** that page might be marked as dirty.  This happens, for example, when
................................................................................
*/
SQLITE_PRIVATE void sqlite3PagerDontWrite(PgHdr *pPg){
  Pager *pPager = pPg->pPager;
  if( (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){
    PAGERTRACE(("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager)));
    IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
    pPg->flags |= PGHDR_DONT_WRITE;
    pPg->flags &= ~PGHDR_WRITEABLE;
    pager_set_pagehash(pPg);
  }
}

/*
** This routine is called to increment the value of the database file 
** change-counter, stored as a 4-byte big-endian integer starting at 
................................................................................
** to make up the difference. If the number of savepoints is already
** equal to nSavepoint, then this function is a no-op.
**
** If a memory allocation fails, SQLITE_NOMEM is returned. If an error 
** occurs while opening the sub-journal file, then an IO error code is
** returned. Otherwise, SQLITE_OK.
*/
static SQLITE_NOINLINE int pagerOpenSavepoint(Pager *pPager, int nSavepoint){
  int rc = SQLITE_OK;                       /* Return code */
  int nCurrent = pPager->nSavepoint;        /* Current number of savepoints */
  int ii;                                   /* Iterator variable */
  PagerSavepoint *aNew;                     /* New Pager.aSavepoint array */

  assert( pPager->eState>=PAGER_WRITER_LOCKED );
  assert( assert_pager_state(pPager) );

  assert( nSavepoint>nCurrent && pPager->useJournal );



  /* Grow the Pager.aSavepoint array using realloc(). Return SQLITE_NOMEM
  ** if the allocation fails. Otherwise, zero the new portion in case a 
  ** malloc failure occurs while populating it in the for(...) loop below.
  */
  aNew = (PagerSavepoint *)sqlite3Realloc(
      pPager->aSavepoint, sizeof(PagerSavepoint)*nSavepoint
  );
  if( !aNew ){
    return SQLITE_NOMEM;
  }
  memset(&aNew[nCurrent], 0, (nSavepoint-nCurrent) * sizeof(PagerSavepoint));
  pPager->aSavepoint = aNew;

  /* Populate the PagerSavepoint structures just allocated. */
  for(ii=nCurrent; ii<nSavepoint; ii++){
    aNew[ii].nOrig = pPager->dbSize;
    if( isOpen(pPager->jfd) && pPager->journalOff>0 ){
      aNew[ii].iOffset = pPager->journalOff;
    }else{
      aNew[ii].iOffset = JOURNAL_HDR_SZ(pPager);
    }
    aNew[ii].iSubRec = pPager->nSubRec;
    aNew[ii].pInSavepoint = sqlite3BitvecCreate(pPager->dbSize);
    if( !aNew[ii].pInSavepoint ){
      return SQLITE_NOMEM;
    }
    if( pagerUseWal(pPager) ){
      sqlite3WalSavepoint(pPager->pWal, aNew[ii].aWalData);
    }
    pPager->nSavepoint = ii+1;
  }
  assert( pPager->nSavepoint==nSavepoint );
  assertTruncateConstraint(pPager);
  return rc;
}
SQLITE_PRIVATE int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
  assert( pPager->eState>=PAGER_WRITER_LOCKED );
  assert( assert_pager_state(pPager) );

  if( nSavepoint>pPager->nSavepoint && pPager->useJournal ){
    return pagerOpenSavepoint(pPager, nSavepoint);
  }else{
    return SQLITE_OK;
  }
}


/*
** This function is called to rollback or release (commit) a savepoint.
** The savepoint to release or rollback need not be the most recently 
** created savepoint.
**
** Parameter op is always either SAVEPOINT_ROLLBACK or SAVEPOINT_RELEASE.
................................................................................
  ** be possible to restore its contents when the "ROLLBACK TO one"
  ** statement were is processed.
  **
  ** subjournalPage() may need to allocate space to store pPg->pgno into
  ** one or more savepoint bitvecs. This is the reason this function
  ** may return SQLITE_NOMEM.
  */
  if( (pPg->flags & PGHDR_DIRTY)!=0

   && SQLITE_OK!=(rc = subjournalPageIfRequired(pPg))
  ){
    return rc;
  }

  PAGERTRACE(("MOVE %d page %d (needSync=%d) moves to %d\n", 
      PAGERID(pPager), pPg->pgno, (pPg->flags&PGHDR_NEED_SYNC)?1:0, pgno));
  IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
................................................................................
  u16 aiOvfl[5];       /* Insert the i-th overflow cell before the aiOvfl-th
                       ** non-overflow cell */
  u8 *apOvfl[5];       /* Pointers to the body of overflow cells */
  BtShared *pBt;       /* Pointer to BtShared that this page is part of */
  u8 *aData;           /* Pointer to disk image of the page data */
  u8 *aDataEnd;        /* One byte past the end of usable data */
  u8 *aCellIdx;        /* The cell index area */
  u8 *aDataOfst;       /* Same as aData for leaves.  aData+4 for interior */
  DbPage *pDbPage;     /* Pager page handle */
  u16 (*xCellSize)(MemPage*,u8*);             /* cellSizePtr method */
  void (*xParseCell)(MemPage*,u8*,CellInfo*); /* btreeParseCell method */
  Pgno pgno;           /* Page number for this page */
};

/*
................................................................................
**    eState==SKIPNEXT && skipNext>0:  Next sqlite3BtreeNext() is no-op.
**    eState==SKIPNEXT && skipNext<0:  Next sqlite3BtreePrevious() is no-op.
**    eState==FAULT:                   Cursor fault with skipNext as error code.
*/
struct BtCursor {
  Btree *pBtree;            /* The Btree to which this cursor belongs */
  BtShared *pBt;            /* The BtShared this cursor points to */
  BtCursor *pNext;          /* Forms a linked list of all cursors */

  Pgno *aOverflow;          /* Cache of overflow page locations */
  CellInfo info;            /* A parse of the cell we are pointing at */
  i64 nKey;                 /* Size of pKey, or last integer key */
  void *pKey;               /* Saved key that was cursor last known position */
  Pgno pgnoRoot;            /* The root page of this tree */
  int nOvflAlloc;           /* Allocated size of aOverflow[] array */
  int skipNext;    /* Prev() is noop if negative. Next() is noop if positive.
                   ** Error code if eState==CURSOR_FAULT */
  u8 curFlags;              /* zero or more BTCF_* flags defined below */
  u8 curPagerFlags;         /* Flags to send to sqlite3PagerAcquire() */
  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
  u8 hints;                 /* As configured by CursorSetHints() */
  /* All fields above are zeroed when the cursor is allocated.  See
  ** sqlite3BtreeCursorZero().  Fields that follow must be manually
  ** initialized. */
  i8 iPage;                 /* Index of current page in apPage */
  u8 curIntKey;             /* Value of apPage[0]->intKey */
  struct KeyInfo *pKeyInfo; /* Argument passed to comparison function */
  void *padding1;           /* Make object size a multiple of 16 */
  u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
};

/*
** Legal values for BtCursor.curFlags
*/
#define BTCF_WriteFlag    0x01   /* True if a write cursor */
#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
#define BTCF_AtLast       0x08   /* Cursor is pointing ot the last entry */
#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */
#define BTCF_Multiple     0x20   /* Maybe another cursor on the same btree */

/*
** Potential values for BtCursor.eState.
**
** CURSOR_INVALID:
**   Cursor does not point to a valid entry. This can happen (for example) 
**   because the table is empty or because BtreeCursorFirst() has not been
................................................................................
** Routines to read or write a two- and four-byte big-endian integer values.
*/
#define get2byte(x)   ((x)[0]<<8 | (x)[1])
#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
#define get4byte sqlite3Get4byte
#define put4byte sqlite3Put4byte

/*
** get2byteAligned(), unlike get2byte(), requires that its argument point to a
** two-byte aligned address.  get2bytea() is only used for accessing the
** cell addresses in a btree header.
*/
#if SQLITE_BYTEORDER==4321
# define get2byteAligned(x)  (*(u16*)(x))
#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4008000
# define get2byteAligned(x)  __builtin_bswap16(*(u16*)(x))
#elif SQLITE_BYTEORDER==1234 && defined(_MSC_VER) && _MSC_VER>=1300
# define get2byteAligned(x)  _byteswap_ushort(*(u16*)(x))
#else
# define get2byteAligned(x)  ((x)[0]<<8 | (x)[1])
#endif

/************** End of btreeInt.h ********************************************/
/************** Continuing where we left off in btmutex.c ********************/
#ifndef SQLITE_OMIT_SHARED_CACHE
#if SQLITE_THREADSAFE

/*
** Obtain the BtShared mutex associated with B-Tree handle p. Also,
................................................................................

  /* If this is an intKey table, then the above call to BtreeKeySize()
  ** stores the integer key in pCur->nKey. In this case this value is
  ** all that is required. Otherwise, if pCur is not open on an intKey
  ** table, then malloc space for and store the pCur->nKey bytes of key 
  ** data.
  */
  if( 0==pCur->curIntKey ){
    void *pKey = sqlite3Malloc( pCur->nKey );
    if( pKey ){
      rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
      if( rc==SQLITE_OK ){
        pCur->pKey = pKey;
      }else{
        sqlite3_free(pKey);
      }
    }else{
      rc = SQLITE_NOMEM;
    }
  }
  assert( !pCur->curIntKey || !pCur->pKey );

  if( rc==SQLITE_OK ){
    btreeReleaseAllCursorPages(pCur);
    pCur->eState = CURSOR_REQUIRESEEK;
  }

  invalidateOverflowCache(pCur);
................................................................................
/*
** Save the positions of all cursors (except pExcept) that are open on
** the table with root-page iRoot.  "Saving the cursor position" means that
** the location in the btree is remembered in such a way that it can be
** moved back to the same spot after the btree has been modified.  This
** routine is called just before cursor pExcept is used to modify the
** table, for example in BtreeDelete() or BtreeInsert().
**
** If there are two or more cursors on the same btree, then all such 
** cursors should have their BTCF_Multiple flag set.  The btreeCursor()
** routine enforces that rule.  This routine only needs to be called in
** the uncommon case when pExpect has the BTCF_Multiple flag set.
**
** If pExpect!=NULL and if no other cursors are found on the same root-page,
** then the BTCF_Multiple flag on pExpect is cleared, to avoid another
** pointless call to this routine.
**
** Implementation note:  This routine merely checks to see if any cursors
** need to be saved.  It calls out to saveCursorsOnList() in the (unusual)
** event that cursors are in need to being saved.
*/
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
  BtCursor *p;
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( pExcept==0 || pExcept->pBt==pBt );
  for(p=pBt->pCursor; p; p=p->pNext){
    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ) break;
  }
  if( p ) return saveCursorsOnList(p, iRoot, pExcept);
  if( pExcept ) pExcept->curFlags &= ~BTCF_Multiple;
  return SQLITE_OK;
}

/* This helper routine to saveAllCursors does the actual work of saving
** the cursors if and when a cursor is found that actually requires saving.
** The common case is that no cursors need to be saved, so this routine is
** broken out from its caller to avoid unnecessary stack pointer movement.
*/
................................................................................
  #define ptrmapPutOvflPtr(x, y, rc)
#endif

/*
** Given a btree page and a cell index (0 means the first cell on
** the page, 1 means the second cell, and so forth) return a pointer
** to the cell content.
**
** findCellPastPtr() does the same except it skips past the initial
** 4-byte child pointer found on interior pages, if there is one.
**
** This routine works only for pages that do not contain overflow cells.
*/
#define findCell(P,I) \
  ((P)->aData + ((P)->maskPage & get2byteAligned(&(P)->aCellIdx[2*(I)])))
#define findCellPastPtr(P,I) \
  ((P)->aDataOfst + ((P)->maskPage & get2byteAligned(&(P)->aCellIdx[2*(I)])))


/*
** This is common tail processing for btreeParseCellPtr() and
** btreeParseCellPtrIndex() for the case when the cell does not fit entirely
** on a single B-tree page.  Make necessary adjustments to the CellInfo
** structure.
*/
................................................................................
    assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
    pPage->maskPage = (u16)(pBt->pageSize - 1);
    pPage->nOverflow = 0;
    usableSize = pBt->usableSize;
    pPage->cellOffset = cellOffset = hdr + 8 + pPage->childPtrSize;
    pPage->aDataEnd = &data[usableSize];
    pPage->aCellIdx = &data[cellOffset];
    pPage->aDataOfst = &data[pPage->childPtrSize];
    /* EVIDENCE-OF: R-58015-48175 The two-byte integer at offset 5 designates
    ** the start of the cell content area. A zero value for this integer is
    ** interpreted as 65536. */
    top = get2byteNotZero(&data[hdr+5]);
    /* EVIDENCE-OF: R-37002-32774 The two-byte integer at offset 3 gives the
    ** number of cells on the page. */
    pPage->nCell = get2byte(&data[hdr+3]);
................................................................................
    iCellLast = usableSize - 4;
    if( pBt->db->flags & SQLITE_CellSizeCk ){
      int i;            /* Index into the cell pointer array */
      int sz;           /* Size of a cell */

      if( !pPage->leaf ) iCellLast--;
      for(i=0; i<pPage->nCell; i++){
        pc = get2byteAligned(&data[cellOffset+i*2]);
        testcase( pc==iCellFirst );
        testcase( pc==iCellLast );
        if( pc<iCellFirst || pc>iCellLast ){
          return SQLITE_CORRUPT_BKPT;
        }
        sz = pPage->xCellSize(pPage, &data[pc]);
        testcase( pc+sz==usableSize );
................................................................................
  data[hdr+7] = 0;
  put2byte(&data[hdr+5], pBt->usableSize);
  pPage->nFree = (u16)(pBt->usableSize - first);
  decodeFlags(pPage, flags);
  pPage->cellOffset = first;
  pPage->aDataEnd = &data[pBt->usableSize];
  pPage->aCellIdx = &data[first];
  pPage->aDataOfst = &data[pPage->childPtrSize];
  pPage->nOverflow = 0;
  assert( pBt->pageSize>=512 && pBt->pageSize<=65536 );
  pPage->maskPage = (u16)(pBt->pageSize - 1);
  pPage->nCell = 0;
  pPage->isInit = 1;
}

................................................................................
*/
static MemPage *btreePageFromDbPage(DbPage *pDbPage, Pgno pgno, BtShared *pBt){
  MemPage *pPage = (MemPage*)sqlite3PagerGetExtra(pDbPage);
  pPage->aData = sqlite3PagerGetData(pDbPage);
  pPage->pDbPage = pDbPage;
  pPage->pBt = pBt;
  pPage->pgno = pgno;
  pPage->hdrOffset = pgno==1 ? 100 : 0;
  return pPage; 
}

/*
** Get a page from the pager.  Initialize the MemPage.pBt and
** MemPage.aData elements if needed.  See also: btreeGetUnusedPage().
**
................................................................................
SQLITE_PRIVATE u32 sqlite3BtreeLastPage(Btree *p){
  assert( sqlite3BtreeHoldsMutex(p) );
  assert( ((p->pBt->nPage)&0x8000000)==0 );
  return btreePagecount(p->pBt);
}

/*
** Get a page from the pager and initialize it.
**
** If pCur!=0 then the page is being fetched as part of a moveToChild()
** call.  Do additional sanity checking on the page in this case.
** And if the fetch fails, this routine must decrement pCur->iPage.
**
** The page is fetched as read-write unless pCur is not NULL and is
** a read-only cursor.
**
** If an error occurs, then *ppPage is undefined. It
** may remain unchanged, or it may be set to an invalid value.
*/
static int getAndInitPage(
  BtShared *pBt,                  /* The database file */
  Pgno pgno,                      /* Number of the page to get */
  MemPage **ppPage,               /* Write the page pointer here */
  BtCursor *pCur,                 /* Cursor to receive the page, or NULL */
  int bReadOnly                   /* True for a read-only page */
){
  int rc;
  DbPage *pDbPage;
  assert( sqlite3_mutex_held(pBt->mutex) );

  assert( pCur==0 || ppPage==&pCur->apPage[pCur->iPage] );
  assert( pCur==0 || bReadOnly==pCur->curPagerFlags );
  assert( pCur==0 || pCur->iPage>0 );

  if( pgno>btreePagecount(pBt) ){
    rc = SQLITE_CORRUPT_BKPT;
    goto getAndInitPage_error;

  }
  rc = sqlite3PagerAcquire(pBt->pPager, pgno, (DbPage**)&pDbPage, bReadOnly);
  if( rc ){
    goto getAndInitPage_error;
  }
  *ppPage = btreePageFromDbPage(pDbPage, pgno, pBt);
  if( (*ppPage)->isInit==0 ){
    rc = btreeInitPage(*ppPage);
    if( rc!=SQLITE_OK ){
      releasePage(*ppPage);
      goto getAndInitPage_error;
    }
  }

  /* If obtaining a child page for a cursor, we must verify that the page is
  ** compatible with the root page. */
  if( pCur
   && ((*ppPage)->nCell<1 || (*ppPage)->intKey!=pCur->curIntKey)
  ){
    rc = SQLITE_CORRUPT_BKPT;
    releasePage(*ppPage);
    goto getAndInitPage_error;
  }
  return SQLITE_OK;

getAndInitPage_error:
  if( pCur ) pCur->iPage--;
  testcase( pgno==0 );
  assert( pgno!=0 || rc==SQLITE_CORRUPT );
  return rc;
}

/*
** Release a MemPage.  This should be called once for each prior
** call to btreeGetPage.
*/
static void releasePageNotNull(MemPage *pPage){

  assert( pPage->aData );
  assert( pPage->pBt );
  assert( pPage->pDbPage!=0 );
  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
  assert( sqlite3PagerGetData(pPage->pDbPage)==pPage->aData );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  sqlite3PagerUnrefNotNull(pPage->pDbPage);
}
static void releasePage(MemPage *pPage){
  if( pPage ) releasePageNotNull(pPage);
}

/*
** Get an unused page.
**
** This works just like btreeGetPage() with the addition:
**
................................................................................
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE );
  if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){
    MemPage *pPage1 = pBt->pPage1;
    assert( pPage1->aData );
    assert( sqlite3PagerRefcount(pBt->pPager)==1 );
    pBt->pPage1 = 0;
    releasePageNotNull(pPage1);
  }
}

/*
** If pBt points to an empty file then convert that empty file
** into a new empty database by initializing the first page of
** the database.
................................................................................
  Btree *p,                              /* The btree */
  int iTable,                            /* Root page of table to open */
  int wrFlag,                            /* 1 to write. 0 read-only */
  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
  BtCursor *pCur                         /* Space for new cursor */
){
  BtShared *pBt = p->pBt;                /* Shared b-tree handle */
  BtCursor *pX;                          /* Looping over other all cursors */

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( wrFlag==0 || wrFlag==1 );

  /* The following assert statements verify that if this is a sharable 
  ** b-tree database, the connection is holding the required table locks, 
  ** and that no other connection has any open cursor that conflicts with 
................................................................................
  assert( hasSharedCacheTableLock(p, iTable, pKeyInfo!=0, wrFlag+1) );
  assert( wrFlag==0 || !hasReadConflicts(p, iTable) );

  /* Assert that the caller has opened the required transaction. */
  assert( p->inTrans>TRANS_NONE );
  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
  assert( pBt->pPage1 && pBt->pPage1->aData );

  assert( wrFlag==0 || (pBt->btsFlags & BTS_READ_ONLY)==0 );


  if( wrFlag ){
    allocateTempSpace(pBt);
    if( pBt->pTmpSpace==0 ) return SQLITE_NOMEM;
  }
  if( iTable==1 && btreePagecount(pBt)==0 ){
    assert( wrFlag==0 );
    iTable = 0;
................................................................................
  pCur->pgnoRoot = (Pgno)iTable;
  pCur->iPage = -1;
  pCur->pKeyInfo = pKeyInfo;
  pCur->pBtree = p;
  pCur->pBt = pBt;
  assert( wrFlag==0 || wrFlag==BTCF_WriteFlag );
  pCur->curFlags = wrFlag;
  pCur->curPagerFlags = wrFlag ? 0 : PAGER_GET_READONLY;
  /* If there are two or more cursors on the same btree, then all such
  ** cursors *must* have the BTCF_Multiple flag set. */
  for(pX=pBt->pCursor; pX; pX=pX->pNext){


    if( pX->pgnoRoot==(Pgno)iTable ){
      pX->curFlags |= BTCF_Multiple;
      pCur->curFlags |= BTCF_Multiple;
    }
  }
  pCur->pNext = pBt->pCursor;
  pBt->pCursor = pCur;
  pCur->eState = CURSOR_INVALID;
  return SQLITE_OK;
}
SQLITE_PRIVATE int sqlite3BtreeCursor(
  Btree *p,                                   /* The btree */
  int iTable,                                 /* Root page of table to open */
................................................................................
SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
  Btree *pBtree = pCur->pBtree;
  if( pBtree ){
    int i;
    BtShared *pBt = pCur->pBt;
    sqlite3BtreeEnter(pBtree);
    sqlite3BtreeClearCursor(pCur);
    assert( pBt->pCursor!=0 );
    if( pBt->pCursor==pCur ){
      pBt->pCursor = pCur->pNext;
    }else{
      BtCursor *pPrev = pBt->pCursor;
      do{
        if( pPrev->pNext==pCur ){
          pPrev->pNext = pCur->pNext;
          break;
        }
        pPrev = pPrev->pNext;

      }while( ALWAYS(pPrev) );
    }
    for(i=0; i<=pCur->iPage; i++){
      releasePage(pCur->apPage[i]);
    }
    unlockBtreeIfUnused(pBt);
    sqlite3_free(pCur->aOverflow);
    /* sqlite3_free(pCur); */
................................................................................
**
** This function returns SQLITE_CORRUPT if the page-header flags field of
** the new child page does not match the flags field of the parent (i.e.
** if an intkey page appears to be the parent of a non-intkey page, or
** vice-versa).
*/
static int moveToChild(BtCursor *pCur, u32 newPgno){



  BtShared *pBt = pCur->pBt;

  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
  assert( pCur->iPage>=0 );
  if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
    return SQLITE_CORRUPT_BKPT;
  }







  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);




  pCur->iPage++;
  pCur->aiIdx[pCur->iPage] = 0;
  return getAndInitPage(pBt, newPgno, &pCur->apPage[pCur->iPage],
                        pCur, pCur->curPagerFlags);
}

#if SQLITE_DEBUG
/*
** Page pParent is an internal (non-leaf) tree page. This function 
** asserts that page number iChild is the left-child if the iIdx'th
** cell in page pParent. Or, if iIdx is equal to the total number of
................................................................................
  assert( pCur->apPage[pCur->iPage] );
  assertParentIndex(
    pCur->apPage[pCur->iPage-1], 
    pCur->aiIdx[pCur->iPage-1], 
    pCur->apPage[pCur->iPage]->pgno
  );
  testcase( pCur->aiIdx[pCur->iPage-1] > pCur->apPage[pCur->iPage-1]->nCell );



  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  releasePageNotNull(pCur->apPage[pCur->iPage--]);
}

/*
** Move the cursor to point to the root page of its b-tree structure.
**
** If the table has a virtual root page, then the cursor is moved to point
** to the virtual root page instead of the actual root page. A table has a
................................................................................
      assert( pCur->skipNext!=SQLITE_OK );
      return pCur->skipNext;
    }
    sqlite3BtreeClearCursor(pCur);
  }

  if( pCur->iPage>=0 ){
    while( pCur->iPage ){
      assert( pCur->apPage[pCur->iPage]!=0 );
      releasePageNotNull(pCur->apPage[pCur->iPage--]);
    }
  }else if( pCur->pgnoRoot==0 ){
    pCur->eState = CURSOR_INVALID;
    return SQLITE_OK;
  }else{
    assert( pCur->iPage==(-1) );
    rc = getAndInitPage(pCur->pBtree->pBt, pCur->pgnoRoot, &pCur->apPage[0],

                        0, pCur->curPagerFlags);
    if( rc!=SQLITE_OK ){
      pCur->eState = CURSOR_INVALID;
      return rc;
    }
    pCur->iPage = 0;
    pCur->curIntKey = pCur->apPage[0]->intKey;
  }
  pRoot = pCur->apPage[0];
  assert( pRoot->pgno==pCur->pgnoRoot );

  /* If pCur->pKeyInfo is not NULL, then the caller that opened this cursor
  ** expected to open it on an index b-tree. Otherwise, if pKeyInfo is
  ** NULL, the caller expects a table b-tree. If this is not the case,
................................................................................
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  assert( pRes );
  assert( (pIdxKey==0)==(pCur->pKeyInfo==0) );

  /* If the cursor is already positioned at the point we are trying
  ** to move to, then just return without doing any work */
  if( pCur->eState==CURSOR_VALID && (pCur->curFlags & BTCF_ValidNKey)!=0
   && pCur->curIntKey 
  ){
    if( pCur->info.nKey==intKey ){
      *pRes = 0;
      return SQLITE_OK;
    }
    if( (pCur->curFlags & BTCF_AtLast)!=0 && pCur->info.nKey<intKey ){
      *pRes = -1;
................................................................................
  assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->isInit );
  assert( pCur->eState==CURSOR_INVALID || pCur->apPage[pCur->iPage]->nCell>0 );
  if( pCur->eState==CURSOR_INVALID ){
    *pRes = -1;
    assert( pCur->pgnoRoot==0 || pCur->apPage[pCur->iPage]->nCell==0 );
    return SQLITE_OK;
  }
  assert( pCur->apPage[0]->intKey==pCur->curIntKey );
  assert( pCur->curIntKey || pIdxKey );
  for(;;){
    int lwr, upr, idx, c;
    Pgno chldPg;
    MemPage *pPage = pCur->apPage[pCur->iPage];
    u8 *pCell;                          /* Pointer to current cell in pPage */

    /* pPage->nCell must be greater than zero. If this is the root-page
................................................................................
    upr = pPage->nCell-1;
    assert( biasRight==0 || biasRight==1 );
    idx = upr>>(1-biasRight); /* idx = biasRight ? upr : (lwr+upr)/2; */
    pCur->aiIdx[pCur->iPage] = (u16)idx;
    if( xRecordCompare==0 ){
      for(;;){
        i64 nCellKey;
        pCell = findCellPastPtr(pPage, idx);
        if( pPage->intKeyLeaf ){
          while( 0x80 <= *(pCell++) ){
            if( pCell>=pPage->aDataEnd ) return SQLITE_CORRUPT_BKPT;
          }
        }
        getVarint(pCell, (u64*)&nCellKey);
        if( nCellKey<intKey ){
................................................................................
        }
        assert( lwr+upr>=0 );
        idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2; */
      }
    }else{
      for(;;){
        int nCell;  /* Size of the pCell cell in bytes */
        pCell = findCellPastPtr(pPage, idx);

        /* The maximum supported page-size is 65536 bytes. This means that
        ** the maximum number of record bytes stored on an index B-Tree
        ** page is less than 16384 bytes and may be stored as a 2-byte
        ** varint. This information is used to attempt to avoid parsing 
        ** the entire cell by checking for the cases where the record is 
        ** stored entirely within the b-tree page by inspecting the first 
................................................................................
  
  /* Fill in the payload size */
  if( pPage->intKey ){
    pSrc = pData;
    nSrc = nData;
    nData = 0;
  }else{ 
    assert( nKey<=0x7fffffff && pKey!=0 );


    nPayload = (int)nKey;
    pSrc = pKey;
    nSrc = (int)nKey;
  }
  if( nPayload<=pPage->maxLocal ){
    n = nHeader + nPayload;
    testcase( n==3 );
................................................................................

  put2byte(&aData[hdr+3], pPg->nCell);
  put2byte(&aData[hdr+5], pData - aData);

#ifdef SQLITE_DEBUG
  for(i=0; i<nNew && !CORRUPT_DB; i++){
    u8 *pCell = pCArray->apCell[i+iNew];
    int iOff = get2byteAligned(&pPg->aCellIdx[i*2]);
    if( pCell>=aData && pCell<&aData[pPg->pBt->usableSize] ){
      pCell = &pTmp[pCell - aData];
    }
    assert( 0==memcmp(pCell, &aData[iOff],
            pCArray->pRef->xCellSize(pCArray->pRef, pCArray->apCell[i+iNew])) );
  }
#endif
................................................................................
  if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
    pRight = &pParent->aData[pParent->hdrOffset+8];
  }else{
    pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
  }
  pgno = get4byte(pRight);
  while( 1 ){
    rc = getAndInitPage(pBt, pgno, &apOld[i], 0, 0);
    if( rc ){
      memset(apOld, 0, (i+1)*sizeof(MemPage*));
      goto balance_cleanup;
    }
    nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
    if( (i--)==0 ) break;

................................................................................
    ** first.
    */
    memset(&b.szCell[b.nCell], 0, sizeof(b.szCell[0])*limit);
    if( pOld->nOverflow>0 ){
      memset(&b.szCell[b.nCell+limit], 0, sizeof(b.szCell[0])*pOld->nOverflow);
      limit = pOld->aiOvfl[0];
      for(j=0; j<limit; j++){
        b.apCell[b.nCell] = aData + (maskPage & get2byteAligned(piCell));
        piCell += 2;
        b.nCell++;
      }
      for(k=0; k<pOld->nOverflow; k++){
        assert( k==0 || pOld->aiOvfl[k-1]+1==pOld->aiOvfl[k] );/* NOTE 1 */
        b.apCell[b.nCell] = pOld->apOvfl[k];
        b.nCell++;
      }
    }
    piEnd = aData + pOld->cellOffset + 2*pOld->nCell;
    while( piCell<piEnd ){
      assert( b.nCell<nMaxCells );
      b.apCell[b.nCell] = aData + (maskPage & get2byteAligned(piCell));
      piCell += 2;
      b.nCell++;
    }

    cntOld[i] = b.nCell;
    if( i<nOld-1 && !leafData){
      u16 sz = (u16)szNew[i];
................................................................................
  ** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the 
  ** integer key to use. It then calls this function to actually insert the 
  ** data into the intkey B-Tree. In this case btreeMoveto() recognizes
  ** that the cursor is already where it needs to be and returns without
  ** doing any work. To avoid thwarting these optimizations, it is important
  ** not to clear the cursor here.
  */
  if( pCur->curFlags & BTCF_Multiple ){
    rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
    if( rc ) return rc;
  }

  if( pCur->pKeyInfo==0 ){
    assert( pKey==0 );
    /* If this is an insert into a table b-tree, invalidate any incrblob 
    ** cursors open on the row being replaced */
    invalidateIncrblobCursors(p, nKey, 0);

    /* If the cursor is currently on the last row and we are appending a
    ** new row onto the end, set the "loc" to avoid an unnecessary
    ** btreeMoveto() call */
    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && nKey>0
      && pCur->info.nKey==nKey-1 ){
       loc = -1;
    }else if( loc==0 ){
      rc = sqlite3BtreeMovetoUnpacked(pCur, 0, nKey, appendBias, &loc);
      if( rc ) return rc;
    }


  }else if( loc==0 ){
    rc = btreeMoveto(pCur, pKey, nKey, appendBias, &loc);
    if( rc ) return rc;
  }
  assert( pCur->eState==CURSOR_VALID || (pCur->eState==CURSOR_INVALID && loc) );

  pPage = pCur->apPage[pCur->iPage];
  assert( pPage->intKey || nKey>=0 );
................................................................................

  assert( cursorHoldsMutex(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( pCur->curFlags & BTCF_WriteFlag );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
  assert( !hasReadConflicts(p, pCur->pgnoRoot) );

  assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
  assert( pCur->eState==CURSOR_VALID );





  iCellDepth = pCur->iPage;
  iCellIdx = pCur->aiIdx[iCellDepth];
  pPage = pCur->apPage[iCellDepth];
  pCell = findCell(pPage, iCellIdx);

  /* If the page containing the entry to delete is not a leaf page, move
................................................................................
  }

  /* Save the positions of any other cursors open on this table before
  ** making any modifications. Make the page containing the entry to be 
  ** deleted writable. Then free any overflow pages associated with the 
  ** entry and finally remove the cell itself from within the page.  
  */
  if( pCur->curFlags & BTCF_Multiple ){
    rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
    if( rc ) return rc;
  }

  /* If this is a delete operation to remove a row from a table b-tree,
  ** invalidate any incrblob cursors open on the row being deleted.  */
  if( pCur->pKeyInfo==0 ){
    invalidateIncrblobCursors(p, pCur->info.nKey, 0);
  }

................................................................................
  int hdr;
  u16 szCell;

  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pgno>btreePagecount(pBt) ){
    return SQLITE_CORRUPT_BKPT;
  }
  rc = getAndInitPage(pBt, pgno, &pPage, 0, 0);
  if( rc ) return rc;
  if( pPage->bBusy ){
    rc = SQLITE_CORRUPT_BKPT;
    goto cleardatabasepage_out;
  }
  pPage->bBusy = 1;
  hdr = pPage->hdrOffset;
................................................................................
    nCell = get2byte(&data[hdr+3]);
    /* EVIDENCE-OF: R-23882-45353 The cell pointer array of a b-tree page
    ** immediately follows the b-tree page header. */
    cellStart = hdr + 12 - 4*pPage->leaf;
    /* EVIDENCE-OF: R-02776-14802 The cell pointer array consists of K 2-byte
    ** integer offsets to the cell contents. */
    for(i=0; i<nCell; i++){
      int pc = get2byteAligned(&data[cellStart+i*2]);
      u32 size = 65536;
      if( pc<=usableSize-4 ){
        size = pPage->xCellSize(pPage, &data[pc]);
      }
      if( (int)(pc+size-1)>=usableSize ){
        pCheck->zPfx = 0;
        checkAppendMsg(pCheck,
................................................................................
  p->bIsReader = 0;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;

    /* NOTE: Be sure to update mkopcodeh.awk when adding or removing
    ** cases from this switch! */
    switch( opcode ){





      case OP_Transaction: {
        if( pOp->p2!=0 ) p->readOnly = 0;
        /* fall thru */
      }
      case OP_AutoCommit:
      case OP_Savepoint: {
        p->bIsReader = 1;
................................................................................
/*
** Delete a P4 value if necessary.
*/
static void freeP4(sqlite3 *db, int p4type, void *p4){
  if( p4 ){
    assert( db );
    switch( p4type ){
      case P4_FUNCCTX: {
        freeEphemeralFunction(db, ((sqlite3_context*)p4)->pFunc);
        /* Fall through into the next case */
      }
      case P4_REAL:
      case P4_INT64:
      case P4_DYNAMIC:
      case P4_INTARRAY: {
        sqlite3DbFree(db, p4);
        break;
      }
................................................................................
      break;
    }
    case P4_FUNCDEF: {
      FuncDef *pDef = pOp->p4.pFunc;
      sqlite3_snprintf(nTemp, zTemp, "%s(%d)", pDef->zName, pDef->nArg);
      break;
    }
#ifdef SQLITE_DEBUG
    case P4_FUNCCTX: {
      FuncDef *pDef = pOp->p4.pCtx->pFunc;
      sqlite3_snprintf(nTemp, zTemp, "%s(%d)", pDef->zName, pDef->nArg);
      break;
    }
#endif
    case P4_INT64: {
      sqlite3_snprintf(nTemp, zTemp, "%lld", *pOp->p4.pI64);
      break;
    }
    case P4_INT32: {
      sqlite3_snprintf(nTemp, zTemp, "%d", pOp->p4.i);
      break;
................................................................................
  n = (u32)pMem->n;
  if( flags & MEM_Zero ){
    n += pMem->u.nZero;
  }
  return ((n*2) + 12 + ((flags&MEM_Str)!=0));
}

/*
** The sizes for serial types less than 12
*/
static const u8 sqlite3SmallTypeSizes[] = {
  0, 1, 2, 3, 4, 6, 8, 8, 0, 0, 0, 0
};

/*
** Return the length of the data corresponding to the supplied serial-type.
*/
SQLITE_PRIVATE u32 sqlite3VdbeSerialTypeLen(u32 serial_type){
  if( serial_type>=12 ){
    return (serial_type-12)/2;
  }else{

    return sqlite3SmallTypeSizes[serial_type];
  }
}

/*
** If we are on an architecture with mixed-endian floating 
** points (ex: ARM7) then swap the lower 4 bytes with the 
** upper 4 bytes.  Return the result.
................................................................................
    if( serial_type==7 ){
      assert( sizeof(v)==sizeof(pMem->u.r) );
      memcpy(&v, &pMem->u.r, sizeof(v));
      swapMixedEndianFloat(v);
    }else{
      v = pMem->u.i;
    }
    len = i = sqlite3SmallTypeSizes[serial_type];
    assert( i>0 );
    do{
      buf[--i] = (u8)(v&0xFF);
      v >>= 8;
    }while( i );
    return len;
  }
................................................................................
  testcase( typeRowid==5 );
  testcase( typeRowid==6 );
  testcase( typeRowid==8 );
  testcase( typeRowid==9 );
  if( unlikely(typeRowid<1 || typeRowid>9 || typeRowid==7) ){
    goto idx_rowid_corruption;
  }
  lenRowid = sqlite3SmallTypeSizes[typeRowid];
  testcase( (u32)m.n==szHdr+lenRowid );
  if( unlikely((u32)m.n<szHdr+lenRowid) ){
    goto idx_rowid_corruption;
  }

  /* Fetch the integer off the end of the index record */
  sqlite3VdbeSerialGet((u8*)&m.z[m.n-lenRowid], typeRowid, &v);
................................................................................
  assert( pOp->p4type==P4_COLLSEQ );
  if( pOp->p1 ){
    sqlite3VdbeMemSetInt64(&aMem[pOp->p1], 0);
  }
  break;
}

/* Opcode: Function0 P1 P2 P3 P4 P5
** Synopsis: r[P3]=func(r[P2@P5])
**
** Invoke a user function (P4 is a pointer to a FuncDef object that
** defines the function) with P5 arguments taken from register P2 and
** successors.  The result of the function is stored in register P3.
** Register P3 must not be one of the function inputs.
**
** P1 is a 32-bit bitmask indicating whether or not each argument to the 
** function was determined to be constant at compile time. If the first
** argument was constant then bit 0 of P1 is set. This is used to determine
** whether meta data associated with a user function argument using the
** sqlite3_set_auxdata() API may be safely retained until the next
** invocation of this opcode.
**
** See also: Function, AggStep, AggFinal
*/
/* Opcode: Function P1 P2 P3 P4 P5
** Synopsis: r[P3]=func(r[P2@P5])
**
** Invoke a user function (P4 is a pointer to an sqlite3_context object that
** contains a pointer to the function to be run) with P5 arguments taken
** from register P2 and successors.  The result of the function is stored
** in register P3.  Register P3 must not be one of the function inputs.
**
** P1 is a 32-bit bitmask indicating whether or not each argument to the 
** function was determined to be constant at compile time. If the first
** argument was constant then bit 0 of P1 is set. This is used to determine
** whether meta data associated with a user function argument using the
** sqlite3_set_auxdata() API may be safely retained until the next
** invocation of this opcode.
**
** SQL functions are initially coded as OP_Function0 with P4 pointing
** to a FuncDef object.  But on first evaluation, the P4 operand is
** automatically converted into an sqlite3_context object and the operation
** changed to this OP_Function opcode.  In this way, the initialization of
** the sqlite3_context object occurs only once, rather than once for each
** evaluation of the function.
**
** See also: Function0, AggStep, AggFinal
*/
case OP_Function0: {
  int n;

  sqlite3_context *pCtx;



  assert( pOp->p4type==P4_FUNCDEF );
  n = pOp->p5;


  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );



  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem-p->nCursor)+1) );
  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
  pCtx = sqlite3DbMallocRaw(db, sizeof(*pCtx) + (n-1)*sizeof(sqlite3_value*));
  if( pCtx==0 ) goto no_mem;
  pCtx->pOut = 0;
  pCtx->pFunc = pOp->p4.pFunc;
  pCtx->iOp = (int)(pOp - aOp);
  pCtx->pVdbe = p;
  pCtx->argc = n;
  pOp->p4type = P4_FUNCCTX;
  pOp->p4.pCtx = pCtx;
  pOp->opcode = OP_Function;
  /* Fall through into OP_Function */
}
case OP_Function: {
  int i;
  sqlite3_context *pCtx;

  assert( pOp->p4type==P4_FUNCCTX );
  pCtx = pOp->p4.pCtx;

  /* If this function is inside of a trigger, the register array in aMem[]
  ** might change from one evaluation to the next.  The next block of code
  ** checks to see if the register array has changed, and if so it
  ** reinitializes the relavant parts of the sqlite3_context object */
  pOut = &aMem[pOp->p3];
  if( pCtx->pOut != pOut ){
    pCtx->pOut = pOut;
    for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
  }

  memAboutToChange(p, pCtx->pOut);
#ifdef SQLITE_DEBUG
  for(i=0; i<pCtx->argc; i++){
    assert( memIsValid(pCtx->argv[i]) );


    REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
  }





#endif
  MemSetTypeFlag(pCtx->pOut, MEM_Null);
  pCtx->fErrorOrAux = 0;
  db->lastRowid = lastRowid;
  (*pCtx->pFunc->xFunc)(pCtx, pCtx->argc, pCtx->argv); /* IMP: R-24505-23230 */
  lastRowid = db->lastRowid;  /* Remember rowid changes made by xFunc */

  /* If the function returned an error, throw an exception */
  if( pCtx->fErrorOrAux ){
    if( pCtx->isError ){
      sqlite3VdbeError(p, "%s", sqlite3_value_text(pCtx->pOut));
      rc = pCtx->isError;
    }
    sqlite3VdbeDeleteAuxData(p, pCtx->iOp, pOp->p1);
  }

  /* Copy the result of the function into register P3 */
  if( pOut->flags & (MEM_Str|MEM_Blob) ){
    sqlite3VdbeChangeEncoding(pCtx->pOut, encoding);
    if( sqlite3VdbeMemTooBig(pCtx->pOut) ) goto too_big;

  }

  REGISTER_TRACE(pOp->p3, pCtx->pOut);
  UPDATE_MAX_BLOBSIZE(pCtx->pOut);
  break;
}

/* Opcode: BitAnd P1 P2 P3 * *
** Synopsis:  r[P3]=r[P1]&r[P2]
**
** Take the bit-wise AND of the values in register P1 and P2 and
................................................................................

  v = 0;
  res = 0;
  pOut = out2Prerelease(p, pOp);
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->pCursor!=0 );
  {

    /* The next rowid or record number (different terms for the same
    ** thing) is obtained in a two-step algorithm.
    **
    ** First we attempt to find the largest existing rowid and add one
    ** to that.  But if the largest existing rowid is already the maximum
    ** positive integer, we have to fall through to the second
    ** probabilistic algorithm
................................................................................
**
** This instruction only works for indices.  The equivalent instruction
** for tables is OP_Insert.
*/
case OP_SorterInsert:       /* in2 */
case OP_IdxInsert: {        /* in2 */
  VdbeCursor *pC;

  int nKey;
  const char *zKey;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( isSorter(pC)==(pOp->opcode==OP_SorterInsert) );
  pIn2 = &aMem[pOp->p2];
  assert( pIn2->flags & MEM_Blob );

  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
  assert( pC->pCursor!=0 );
  assert( pC->isTable==0 );
  rc = ExpandBlob(pIn2);
  if( rc==SQLITE_OK ){
    if( pOp->opcode==OP_SorterInsert ){
      rc = sqlite3VdbeSorterWrite(pC, pIn2);
    }else{
      nKey = pIn2->n;
      zKey = pIn2->z;
      rc = sqlite3BtreeInsert(pC->pCursor, zKey, nKey, "", 0, 0, pOp->p3, 
          ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
          );
      assert( pC->deferredMoveto==0 );
      pC->cacheStatus = CACHE_STALE;
    }
  }
  break;
................................................................................
  pIn1 = &aMem[pOp->p1];
  assert( pIn1->flags&MEM_Int );
  VdbeBranchTaken(pIn1->u.i==0, 2);
  if( (pIn1->u.i++)==0 ) goto jump_to_p2;
  break;
}

/* Opcode: AggStep0 * P2 P3 P4 P5
** Synopsis: accum=r[P3] step(r[P2@P5])
**
** Execute the step function for an aggregate.  The
** function has P5 arguments.   P4 is a pointer to the FuncDef
** structure that specifies the function.  Register P3 is the
** accumulator.
**
** The P5 arguments are taken from register P2 and its
** successors.
*/
/* Opcode: AggStep * P2 P3 P4 P5
** Synopsis: accum=r[P3] step(r[P2@P5])
**
** Execute the step function for an aggregate.  The
** function has P5 arguments.   P4 is a pointer to an sqlite3_context
** object that is used to run the function.  Register P3 is
** as the accumulator.
**
** The P5 arguments are taken from register P2 and its
** successors.
**
** This opcode is initially coded as OP_AggStep0.  On first evaluation,
** the FuncDef stored in P4 is converted into an sqlite3_context and
** the opcode is changed.  In this way, the initialization of the
** sqlite3_context only happens once, instead of on each call to the
** step function.
*/
case OP_AggStep0: {
  int n;
  sqlite3_context *pCtx;

  assert( pOp->p4type==P4_FUNCDEF );
  n = pOp->p5;
  assert( pOp->p3>0 && pOp->p3<=(p->nMem-p->nCursor) );
  assert( n==0 || (pOp->p2>0 && pOp->p2+n<=(p->nMem-p->nCursor)+1) );
  assert( pOp->p3<pOp->p2 || pOp->p3>=pOp->p2+n );
  pCtx = sqlite3DbMallocRaw(db, sizeof(*pCtx) + (n-1)*sizeof(sqlite3_value*));
  if( pCtx==0 ) goto no_mem;
  pCtx->pMem = 0;
  pCtx->pFunc = pOp->p4.pFunc;
  pCtx->iOp = (int)(pOp - aOp);
  pCtx->pVdbe = p;
  pCtx->argc = n;
  pOp->p4type = P4_FUNCCTX;
  pOp->p4.pCtx = pCtx;
  pOp->opcode = OP_AggStep;
  /* Fall through into OP_AggStep */
}
case OP_AggStep: {
  int i;
  sqlite3_context *pCtx;
  Mem *pMem;

  Mem t;



  assert( pOp->p4type==P4_FUNCCTX );
  pCtx = pOp->p4.pCtx;

  pMem = &aMem[pOp->p3];



  /* If this function is inside of a trigger, the register array in aMem[]
  ** might change from one evaluation to the next.  The next block of code
  ** checks to see if the register array has changed, and if so it
  ** reinitializes the relavant parts of the sqlite3_context object */
  if( pCtx->pMem != pMem ){
    pCtx->pMem = pMem;
    for(i=pCtx->argc-1; i>=0; i--) pCtx->argv[i] = &aMem[pOp->p2+i];
  }

#ifdef SQLITE_DEBUG
  for(i=0; i<pCtx->argc; i++){
    assert( memIsValid(pCtx->argv[i]) );


    REGISTER_TRACE(pOp->p2+i, pCtx->argv[i]);
  }



#endif

  pMem->n++;
  sqlite3VdbeMemInit(&t, db, MEM_Null);
  pCtx->pOut = &t;



  pCtx->fErrorOrAux = 0;
  pCtx->skipFlag = 0;
  (pCtx->pFunc->xStep)(pCtx,pCtx->argc,pCtx->argv); /* IMP: R-24505-23230 */
  if( pCtx->fErrorOrAux ){
    if( pCtx->isError ){
      sqlite3VdbeError(p, "%s", sqlite3_value_text(&t));
      rc = pCtx->isError;
    }
    sqlite3VdbeMemRelease(&t);
  }else{
    assert( t.flags==MEM_Null );
  }
  if( pCtx->skipFlag ){
    assert( pOp[-1].opcode==OP_CollSeq );
    i = pOp[-1].p1;
    if( i ) sqlite3VdbeMemSetInt64(&aMem[i], 1);
  }

  break;
}

/* Opcode: AggFinal P1 P2 * P4 *
** Synopsis: accum=r[P1] N=P2
**
** Execute the finalizer function for an aggregate.  P1 is
................................................................................
        pDef = sqlite3VtabOverloadFunction(db, pDef, nFarg, pFarg->a[0].pExpr);
      }
#endif
      if( pDef->funcFlags & SQLITE_FUNC_NEEDCOLL ){
        if( !pColl ) pColl = db->pDfltColl; 
        sqlite3VdbeAddOp4(v, OP_CollSeq, 0, 0, 0, (char *)pColl, P4_COLLSEQ);
      }
      sqlite3VdbeAddOp4(v, OP_Function0, constMask, r1, target,
                        (char*)pDef, P4_FUNCDEF);
      sqlite3VdbeChangeP5(v, (u8)nFarg);
      if( nFarg && constMask==0 ){
        sqlite3ReleaseTempRange(pParse, r1, nFarg);
      }
      break;
    }
................................................................................
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
  sqlite3VdbeAddOp2(v, OP_Integer, iParam, regStat4+1);
#elif SQLITE_DEBUG
  assert( iParam==STAT_GET_STAT1 );
#else
  UNUSED_PARAMETER( iParam );
#endif
  sqlite3VdbeAddOp3(v, OP_Function0, 0, regStat4, regOut);
  sqlite3VdbeChangeP4(v, -1, (char*)&statGetFuncdef, P4_FUNCDEF);
  sqlite3VdbeChangeP5(v, 1 + IsStat34);
}

/*
** Generate code to do an analysis of all indices associated with
** a single table.
................................................................................
    ** The third argument is only used for STAT3 and STAT4
    */
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
    sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat4+3);
#endif
    sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat4+1);
    sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regStat4+2);
    sqlite3VdbeAddOp3(v, OP_Function0, 0, regStat4+1, regStat4);
    sqlite3VdbeChangeP4(v, -1, (char*)&statInitFuncdef, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, 2+IsStat34);

    /* Implementation of the following:
    **
    **   Rewind csr
    **   if eof(csr) goto end_of_scan;
................................................................................
        VdbeComment((v, "%s", pTab->aCol[pPk->aiColumn[j]].zName));
      }
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regKey, pPk->nKeyCol, regRowid);
      sqlite3ReleaseTempRange(pParse, regKey, pPk->nKeyCol);
    }
#endif
    assert( regChng==(regStat4+1) );
    sqlite3VdbeAddOp3(v, OP_Function0, 1, regStat4, regTemp);
    sqlite3VdbeChangeP4(v, -1, (char*)&statPushFuncdef, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, 2+IsStat34);
    sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, addrNextRow); VdbeCoverage(v);

    /* Add the entry to the stat1 table. */
    callStatGet(v, regStat4, STAT_GET_STAT1, regStat1);
    assert( "BBB"[0]==SQLITE_AFF_TEXT );
................................................................................
  regArgs = sqlite3GetTempRange(pParse, 4);
  sqlite3ExprCode(pParse, pFilename, regArgs);
  sqlite3ExprCode(pParse, pDbname, regArgs+1);
  sqlite3ExprCode(pParse, pKey, regArgs+2);

  assert( v || db->mallocFailed );
  if( v ){
    sqlite3VdbeAddOp3(v, OP_Function0, 0, regArgs+3-pFunc->nArg, regArgs+3);
    assert( pFunc->nArg==-1 || (pFunc->nArg&0xff)==pFunc->nArg );
    sqlite3VdbeChangeP5(v, (u8)(pFunc->nArg));
    sqlite3VdbeChangeP4(v, -1, (char *)pFunc, P4_FUNCDEF);

    /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this
    ** statement only). For DETACH, set it to false (expire all existing
    ** statements).
................................................................................
      }
      if( !pColl ){
        pColl = pParse->db->pDfltColl;
      }
      if( regHit==0 && pAggInfo->nAccumulator ) regHit = ++pParse->nMem;
      sqlite3VdbeAddOp4(v, OP_CollSeq, regHit, 0, 0, (char *)pColl, P4_COLLSEQ);
    }
    sqlite3VdbeAddOp4(v, OP_AggStep0, 0, regAgg, pF->iMem,
                      (void*)pF->pFunc, P4_FUNCDEF);
    sqlite3VdbeChangeP5(v, (u8)nArg);
    sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
    sqlite3ReleaseTempRange(pParse, regAgg, nArg);
    if( addrNext ){
      sqlite3VdbeResolveLabel(v, addrNext);
      sqlite3ExprCacheClear(pParse);
................................................................................
** the offset of the method to call in the sqlite3_module structure.
**
** The array is cleared after invoking the callbacks. 
*/
static void callFinaliser(sqlite3 *db, int offset){
  int i;
  if( db->aVTrans ){
    VTable **aVTrans = db->aVTrans;
    db->aVTrans = 0;
    for(i=0; i<db->nVTrans; i++){
      VTable *pVTab = aVTrans[i];
      sqlite3_vtab *p = pVTab->pVtab;
      if( p ){
        int (*x)(sqlite3_vtab *);
        x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset);
        if( x ) x(p);
      }
      pVTab->iSavepoint = 0;
      sqlite3VtabUnlock(pVTab);
    }
    sqlite3DbFree(db, aVTrans);
    db->nVTrans = 0;

  }
}

/*
** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans
** array. Return the error code for the first error that occurs, or
** SQLITE_OK if all xSync operations are successful.
................................................................................
*/
static int yy_pop_parser_stack(yyParser *pParser){
  YYCODETYPE yymajor;
  yyStackEntry *yytos = &pParser->yystack[pParser->yyidx];

  /* There is no mechanism by which the parser stack can be popped below
  ** empty in SQLite.  */
  assert( pParser->yyidx>=0 );
#ifndef NDEBUG
  if( yyTraceFILE && pParser->yyidx>=0 ){
    fprintf(yyTraceFILE,"%sPopping %s\n",
      yyTracePrompt,
      yyTokenName[yytos->major]);
  }
#endif
................................................................................
  zSql8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zSql8 ){
    rc = sqlite3_complete(zSql8);
  }else{
    rc = SQLITE_NOMEM;
  }
  sqlite3ValueFree(pVal);
  return rc & 0xff;
}
#endif /* SQLITE_OMIT_UTF16 */
#endif /* SQLITE_OMIT_COMPLETE */

/************** End of complete.c ********************************************/
/************** Begin file main.c ********************************************/
/*
................................................................................
#ifdef SQLITE_ENABLE_SQLLOG
  if( sqlite3GlobalConfig.xSqllog ){
    /* Opening a db handle. Fourth parameter is passed 0. */
    void *pArg = sqlite3GlobalConfig.pSqllogArg;
    sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
  }
#endif
  return rc & 0xff;
}

/*
** Open a new database handle.
*/
SQLITE_API int SQLITE_STDCALL sqlite3_open(
  const char *zFilename, 
................................................................................
      SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
    }
  }else{
    rc = SQLITE_NOMEM;
  }
  sqlite3ValueFree(pVal);

  return rc & 0xff;
}
#endif /* SQLITE_OMIT_UTF16 */

/*
** Register a new collation sequence with the database handle db.
*/
SQLITE_API int SQLITE_STDCALL sqlite3_create_collation(
................................................................................
** File control method. For custom operations on an otaVfs-file.
*/
static int otaVfsFileControl(sqlite3_file *pFile, int op, void *pArg){
  ota_file *p = (ota_file *)pFile;
  int (*xControl)(sqlite3_file*,int,void*) = p->pReal->pMethods->xFileControl;
  int rc;

  assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB)
       || p->openFlags & (SQLITE_OPEN_TRANSIENT_DB|SQLITE_OPEN_TEMP_JOURNAL)
  );
  if( op==SQLITE_FCNTL_OTA ){
    sqlite3ota *pOta = (sqlite3ota*)pArg;

    /* First try to find another OTA vfs lower down in the vfs stack. If
    ** one is found, this vfs will operate in pass-through mode. The lower
    ** level vfs will do the special OTA handling.  */

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.8.11"
#define SQLITE_VERSION_NUMBER 3008011
#define SQLITE_SOURCE_ID      "2015-06-26 02:41:31 015302f15e46a087ec92f3644c6741600dbf4306"

/*
** 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

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.8.11"
#define SQLITE_VERSION_NUMBER 3008011
#define SQLITE_SOURCE_ID      "2015-06-30 17:28:40 fe144dd73f7097a17c24c7812c2a1cc40466e6da"

/*
** 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