System.Data.SQLite

    ///////////////////////////////////////////////////////////////////////////////////////////////

    /// <summary>
    /// Attempts to bind the specified <see cref="SQLiteFunction" /> object
    /// instance to this connection.
    /// </summary>
    /// <param name="functionAttribute">
    /// The <see cref="SQLiteFunctionAttribute" /> object instance containing
    /// the metadata for the function to be bound.
    /// </param>
    /// <param name="function">
    /// The <see cref="SQLiteFunction" /> object instance that implements the
    /// function to be bound.
    /// </param>
    public void BindFunction(
        SQLiteFunctionAttribute functionAttribute,
        SQLiteFunction function
        )
    {

    ///////////////////////////////////////////////////////////////////////////////////////////////

    /// <summary>
    /// Attempts to unbind the specified <see cref="SQLiteFunction" /> object
    /// instance to this connection.
    /// </summary>
    /// <param name="functionAttribute">
    /// The <see cref="SQLiteFunctionAttribute" /> object instance containing
    /// the metadata for the function to be unbound.
    /// </param>
    /// <returns>Non-zero if the function was unbound.</returns>
    public bool UnbindFunction(
        SQLiteFunctionAttribute functionAttribute
        )
    {

    /// </summary>
    private SQLiteCallback  _StepFunc;
    /// <summary>
    /// Holds a reference to the callback function for finalizing an aggregate function
    /// </summary>
    private SQLiteFinalCallback  _FinalFunc;
    /// <summary>
    /// Holds a reference to the callback function for collating sequences
    /// </summary>
    private SQLiteCollation _CompareFunc;

    private SQLiteCollation _CompareFunc16;

    /// <summary>
    /// Current context of the current callback.  Only valid during a callback

    public virtual object Final(object contextData)
    {
      CheckDisposed();
      return null;
    }

    /// <summary>
    /// User-defined collating sequences override this method to provide a custom string sorting algorithm.
    /// </summary>
    /// <param name="param1">The first string to compare.</param>
    /// <param name="param2">The second strnig to compare.</param>
    /// <returns>1 if param1 is greater than param2, 0 if they are equal, or -1 if param1 is less than param2.</returns>
    public virtual int Compare(string param1, string param2)
    {
      CheckDisposed();
      return 0;
    }

    /// <summary>

            {
                // do nothing.
            }
        }
    }

    /// <summary>
    /// Internal collating sequence function, which wraps up the raw string pointers and executes the Compare() virtual function.
    /// WARNING: Must not throw exceptions.
    /// </summary>
    /// <param name="ptr">Not used</param>
    /// <param name="len1">Length of the string pv1</param>
    /// <param name="ptr1">Pointer to the first string to compare</param>
    /// <param name="len2">Length of the string pv2</param>
    /// <param name="ptr2">Pointer to the second string to compare</param>

        if ((_base != null) && _base.IsOpen())
            _base.Cancel();

        return 0;
    }

    /// <summary>
    /// Internal collating sequence function, which wraps up the raw string pointers and executes the Compare() virtual function.
    /// WARNING: Must not throw exceptions.
    /// </summary>
    /// <param name="ptr">Not used</param>
    /// <param name="len1">Length of the string pv1</param>
    /// <param name="ptr1">Pointer to the first string to compare</param>
    /// <param name="len2">Length of the string pv2</param>
    /// <param name="ptr2">Pointer to the second string to compare</param>

    /// <summary>
    /// Manual method of registering a function.  The type must still have the SQLiteFunctionAttributes in order to work
    /// properly, but this is a workaround for the Compact Framework where enumerating assemblies is not currently supported.
    /// </summary>
    /// <param name="typ">The type of the function to register</param>
    public static void RegisterFunction(Type typ)
    {
        object[] arAtt = typ.GetCustomAttributes(

            typeof(SQLiteFunctionAttribute), false);

        for (int y = 0; y < arAtt.Length; y++)
        {
            SQLiteFunctionAttribute at = arAtt[y] as SQLiteFunctionAttribute;

            if (at == null)
                continue;

            at.InstanceType = typ;
            _registeredFunctions.Add(at, null);
        }

    }

    /// <summary>
    /// Called by the SQLiteBase derived classes, this method binds all registered (known) user-defined functions to a connection.
    /// It is done this way so that all user-defined functions will access the database using the same encoding scheme
    /// as the connection (UTF-8 or UTF-16).
    /// </summary>

            }
        }

        return result;
    }

    /// <summary>
    /// This function binds a user-defined function to a connection.
    /// </summary>
    /// <param name="sqliteBase">
    /// The <see cref="SQLiteBase" /> object instance associated with the
    /// <see cref="SQLiteConnection" /> that the function should be bound to.
    /// </param>
    /// <param name="functionAttribute">
    /// The <see cref="SQLiteFunctionAttribute"/> object instance containing

    Scalar = 0,
    /// <summary>
    /// Aggregate functions are designed to accumulate data until the end of a call and then return a result gleaned from the accumulated data.
    /// Examples include SUM(), COUNT(), AVG(), etc.
    /// </summary>
    Aggregate = 1,
    /// <summary>
    /// Collating sequences are used to sort textual data in a custom manner, and appear in an ORDER BY clause.  Typically text in an ORDER BY is
    /// sorted using a straight case-insensitive comparison function.  Custom collating sequences can be used to alter the behavior of text sorting
    /// in a user-defined manner.
    /// </summary>
    Collation = 2,
  }

  /// <summary>

  /// </summary>
  /// <param name="context">Raw context pointer for the user function</param>
#if !PLATFORM_COMPACTFRAMEWORK
  [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
#endif
  internal delegate void SQLiteFinalCallback(IntPtr context);
  /// <summary>
  /// Internal callback delegate for implementing collating sequences
  /// </summary>
  /// <param name="puser">Not used</param>
  /// <param name="len1">Length of the string pv1</param>
  /// <param name="pv1">Pointer to the first string to compare</param>
  /// <param name="len2">Length of the string pv2</param>
  /// <param name="pv2">Pointer to the second string to compare</param>
  /// <returns>Returns -1 if the first string is less than the second.  0 if they are equal, or 1 if the first string is greater

/********************************************************
 * ADO.NET 2.0 Data Provider for SQLite Version 3.X
 * Written by Robert Simpson (robert@blackcastlesoft.com)
 *
 * Released to the public domain, use at your own risk!
 ********************************************************/

namespace System.Data.SQLite
{
  using System;