**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Memory allocation functions used throughout sqlite.
**
**
** $Id: malloc.c,v 1.14 2007/10/20 16:36:31 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** This routine runs when the memory allocator sees that the
................................................................................
}

/*
** Release memory held by SQLite instances created by the current thread.
*/
int sqlite3_release_memory(int n){
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT

  return sqlite3PagerReleaseMemory(n);

#else
  return SQLITE_OK;
#endif
}


/*

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Memory allocation functions used throughout sqlite.
**
**
** $Id: malloc.c,v 1.15 2008/03/26 18:34:43 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <ctype.h>

/*
** This routine runs when the memory allocator sees that the
................................................................................
}

/*
** Release memory held by SQLite instances created by the current thread.
*/
int sqlite3_release_memory(int n){
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  int nRet = sqlite3VdbeReleaseMemory(n);
  nRet += sqlite3PagerReleaseMemory(n-nRet);
  return nRet;
#else
  return SQLITE_OK;
#endif
}


/*

** exclusion and is thus suitable for use only in applications
** that use SQLite in a single thread.  But this implementation
** does do a lot of error checking on mutexes to make sure they
** are called correctly and at appropriate times.  Hence, this
** implementation is suitable for testing.
** debugging purposes
**
** $Id: mutex.c,v 1.16 2007/09/10 16:13:00 danielk1977 Exp $
*/
#include "sqliteInt.h"

#ifdef SQLITE_MUTEX_NOOP_DEBUG
/*
** In this implementation, mutexes do not provide any mutual exclusion.
** But the error checking is provided.  This implementation is useful
................................................................................

/*
** The sqlite3_mutex_alloc() routine allocates a new
** mutex and returns a pointer to it.  If it returns NULL
** that means that a mutex could not be allocated. 
*/
sqlite3_mutex *sqlite3_mutex_alloc(int id){
  static sqlite3_mutex aStatic[5];
  sqlite3_mutex *pNew = 0;
  switch( id ){
    case SQLITE_MUTEX_FAST:
    case SQLITE_MUTEX_RECURSIVE: {
      pNew = sqlite3_malloc(sizeof(*pNew));
      if( pNew ){
        pNew->id = id;

** exclusion and is thus suitable for use only in applications
** that use SQLite in a single thread.  But this implementation
** does do a lot of error checking on mutexes to make sure they
** are called correctly and at appropriate times.  Hence, this
** implementation is suitable for testing.
** debugging purposes
**
** $Id: mutex.c,v 1.17 2008/03/26 18:34:43 danielk1977 Exp $
*/
#include "sqliteInt.h"

#ifdef SQLITE_MUTEX_NOOP_DEBUG
/*
** In this implementation, mutexes do not provide any mutual exclusion.
** But the error checking is provided.  This implementation is useful
................................................................................

/*
** The sqlite3_mutex_alloc() routine allocates a new
** mutex and returns a pointer to it.  If it returns NULL
** that means that a mutex could not be allocated. 
*/
sqlite3_mutex *sqlite3_mutex_alloc(int id){
  static sqlite3_mutex aStatic[6];
  sqlite3_mutex *pNew = 0;
  switch( id ){
    case SQLITE_MUTEX_FAST:
    case SQLITE_MUTEX_RECURSIVE: {
      pNew = sqlite3_malloc(sizeof(*pNew));
      if( pNew ){
        pNew->id = id;

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for OS/2
**
** $Id: mutex_os2.c,v 1.5 2008/02/01 19:42:38 pweilbacher Exp $
*/
#include "sqliteInt.h"

/*
** The code in this file is only used if SQLITE_MUTEX_OS2 is defined.
** See the mutex.h file for details.
*/
................................................................................
        }
      }
      break;
    }
    default: {
      static volatile int isInit = 0;
      static sqlite3_mutex staticMutexes[] = {

        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
      };
      if ( !isInit ){

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for OS/2
**
** $Id: mutex_os2.c,v 1.6 2008/03/26 18:34:43 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The code in this file is only used if SQLITE_MUTEX_OS2 is defined.
** See the mutex.h file for details.
*/
................................................................................
        }
      }
      break;
    }
    default: {
      static volatile int isInit = 0;
      static sqlite3_mutex staticMutexes[] = {
        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
        { OS2_MUTEX_INITIALIZER, },
      };
      if ( !isInit ){

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for pthreads
**
** $Id: mutex_unix.c,v 1.5 2007/11/28 14:04:57 drh Exp $
*/
#include "sqliteInt.h"

/*
** The code in this file is only used if we are compiling threadsafe
** under unix with pthreads.
**
................................................................................
** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
** returns a different mutex on every call.  But for the static 
** mutex types, the same mutex is returned on every call that has
** the same type number.
*/
sqlite3_mutex *sqlite3_mutex_alloc(int iType){
  static sqlite3_mutex staticMutexes[] = {

    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
  };
  sqlite3_mutex *p;

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for pthreads
**
** $Id: mutex_unix.c,v 1.6 2008/03/26 18:34:43 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The code in this file is only used if we are compiling threadsafe
** under unix with pthreads.
**
................................................................................
** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
** returns a different mutex on every call.  But for the static 
** mutex types, the same mutex is returned on every call that has
** the same type number.
*/
sqlite3_mutex *sqlite3_mutex_alloc(int iType){
  static sqlite3_mutex staticMutexes[] = {
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
    { PTHREAD_MUTEX_INITIALIZER, },
  };
  sqlite3_mutex *p;

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for win32
**
** $Id: mutex_w32.c,v 1.5 2007/10/05 15:08:01 drh Exp $
*/
#include "sqliteInt.h"

/*
** The code in this file is only used if we are compiling multithreaded
** on a win32 system.
*/
................................................................................
      if( p ){
        p->id = iType;
        InitializeCriticalSection(&p->mutex);
      }
      break;
    }
    default: {
      static sqlite3_mutex staticMutexes[5];
      static int isInit = 0;
      while( !isInit ){
        static long lock = 0;
        if( InterlockedIncrement(&lock)==1 ){
          int i;
          for(i=0; i<sizeof(staticMutexes)/sizeof(staticMutexes[0]); i++){
            InitializeCriticalSection(&staticMutexes[i].mutex);

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement mutexes for win32
**
** $Id: mutex_w32.c,v 1.6 2008/03/26 18:34:43 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The code in this file is only used if we are compiling multithreaded
** on a win32 system.
*/
................................................................................
      if( p ){
        p->id = iType;
        InitializeCriticalSection(&p->mutex);
      }
      break;
    }
    default: {
      static sqlite3_mutex staticMutexes[6];
      static int isInit = 0;
      while( !isInit ){
        static long lock = 0;
        if( InterlockedIncrement(&lock)==1 ){
          int i;
          for(i=0; i<sizeof(staticMutexes)/sizeof(staticMutexes[0]); i++){
            InitializeCriticalSection(&staticMutexes[i].mutex);

** on how SQLite interfaces are suppose to operate.
**
** The name of this file under configuration management is "sqlite.h.in".
** The makefile makes some minor changes to this file (such as inserting
** the version number) and changes its name to "sqlite3.h" as
** part of the build process.
**
** @(#) $Id: sqlite.h.in,v 1.300 2008/03/24 12:51:46 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.
................................................................................
** <li>  SQLITE_MUTEX_FAST
** <li>  SQLITE_MUTEX_RECURSIVE
** <li>  SQLITE_MUTEX_STATIC_MASTER
** <li>  SQLITE_MUTEX_STATIC_MEM
** <li>  SQLITE_MUTEX_STATIC_MEM2
** <li>  SQLITE_MUTEX_STATIC_PRNG
** <li>  SQLITE_MUTEX_STATIC_LRU

** </ul> {END}
**
** {F17015} The first two constants cause sqlite3_mutex_alloc() to create
** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
** The mutex implementation does not need to make a distinction
** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
................................................................................
#define SQLITE_MUTEX_FAST             0
#define SQLITE_MUTEX_RECURSIVE        1
#define SQLITE_MUTEX_STATIC_MASTER    2
#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
#define SQLITE_MUTEX_STATIC_MEM2      4  /* sqlite3_release_memory() */
#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */


/*
** CAPI3REF: Low-Level Control Of Database Files {F11300}
**
** {F11301} The [sqlite3_file_control()] interface makes a direct call to the
** xFileControl method for the [sqlite3_io_methods] object associated
** with a particular database identified by the second argument. {F11302} The

** on how SQLite interfaces are suppose to operate.
**
** The name of this file under configuration management is "sqlite.h.in".
** The makefile makes some minor changes to this file (such as inserting
** the version number) and changes its name to "sqlite3.h" as
** part of the build process.
**
** @(#) $Id: sqlite.h.in,v 1.301 2008/03/26 18:34:43 danielk1977 Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.
................................................................................
** <li>  SQLITE_MUTEX_FAST
** <li>  SQLITE_MUTEX_RECURSIVE
** <li>  SQLITE_MUTEX_STATIC_MASTER
** <li>  SQLITE_MUTEX_STATIC_MEM
** <li>  SQLITE_MUTEX_STATIC_MEM2
** <li>  SQLITE_MUTEX_STATIC_PRNG
** <li>  SQLITE_MUTEX_STATIC_LRU
** <li>  SQLITE_MUTEX_STATIC_LRU2
** </ul> {END}
**
** {F17015} The first two constants cause sqlite3_mutex_alloc() to create
** a new mutex.  The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END}
** The mutex implementation does not need to make a distinction
** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
................................................................................
#define SQLITE_MUTEX_FAST             0
#define SQLITE_MUTEX_RECURSIVE        1
#define SQLITE_MUTEX_STATIC_MASTER    2
#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
#define SQLITE_MUTEX_STATIC_MEM2      4  /* sqlite3_release_memory() */
#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
#define SQLITE_MUTEX_STATIC_LRU2      7  /* lru page list */

/*
** CAPI3REF: Low-Level Control Of Database Files {F11300}
**
** {F11301} The [sqlite3_file_control()] interface makes a direct call to the
** xFileControl method for the [sqlite3_io_methods] object associated
** with a particular database identified by the second argument. {F11302} The

*************************************************************************
** Header file for the Virtual DataBase Engine (VDBE)
**
** This header defines the interface to the virtual database engine
** or VDBE.  The VDBE implements an abstract machine that runs a
** simple program to access and modify the underlying database.
**
** $Id: vdbe.h,v 1.128 2008/03/25 17:23:34 drh Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines
................................................................................
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  void sqlite3VdbeTrace(Vdbe*,FILE*);
#endif
void sqlite3VdbeResetStepResult(Vdbe*);
int sqlite3VdbeReset(Vdbe*);
void sqlite3VdbeSetNumCols(Vdbe*,int);
int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, int);
void sqlite3VdbeCountChanges(Vdbe*);
sqlite3 *sqlite3VdbeDb(Vdbe*);
void sqlite3VdbeSetSql(Vdbe*, const char *z, int n);
void sqlite3VdbeSwap(Vdbe*,Vdbe*);


UnpackedRecord *sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,void*,int);
void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord*);
int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);


#ifndef NDEBUG
  void sqlite3VdbeComment(Vdbe*, const char*, ...);
# define VdbeComment(X)  sqlite3VdbeComment X
#else
# define VdbeComment(X)
#endif

#endif

*************************************************************************
** Header file for the Virtual DataBase Engine (VDBE)
**
** This header defines the interface to the virtual database engine
** or VDBE.  The VDBE implements an abstract machine that runs a
** simple program to access and modify the underlying database.
**
** $Id: vdbe.h,v 1.129 2008/03/26 18:34:43 danielk1977 Exp $
*/
#ifndef _SQLITE_VDBE_H_
#define _SQLITE_VDBE_H_
#include <stdio.h>

/*
** A single VDBE is an opaque structure named "Vdbe".  Only routines
................................................................................
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  void sqlite3VdbeTrace(Vdbe*,FILE*);
#endif
void sqlite3VdbeResetStepResult(Vdbe*);
int sqlite3VdbeReset(Vdbe*, int);
void sqlite3VdbeSetNumCols(Vdbe*,int);
int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, int);
void sqlite3VdbeCountChanges(Vdbe*);
sqlite3 *sqlite3VdbeDb(Vdbe*);
void sqlite3VdbeSetSql(Vdbe*, const char *z, int n);
void sqlite3VdbeSwap(Vdbe*,Vdbe*);

int sqlite3VdbeReleaseMemory(int);
UnpackedRecord *sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,void*,int);
void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord*);
int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);


#ifndef NDEBUG
  void sqlite3VdbeComment(Vdbe*, const char*, ...);
# define VdbeComment(X)  sqlite3VdbeComment X
#else
# define VdbeComment(X)
#endif

#endif

  FILE *trace;        /* Write an execution trace here, if not NULL */
#endif
  int openedStatement;  /* True if this VM has opened a statement journal */
#ifdef SQLITE_SSE
  int fetchId;          /* Statement number used by sqlite3_fetch_statement */
  int lru;              /* Counter used for LRU cache replacement */
#endif




};

/*
** An instance of the following structure holds information about a
** single index record that has already been parsed out into individual
** values.
**
................................................................................
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeOpcodeHasProperty(int, int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);


#ifndef NDEBUG
  void sqlite3VdbeMemSanity(Mem*);
#endif
int sqlite3VdbeMemTranslate(Mem*, u8);
#ifdef SQLITE_DEBUG
  void sqlite3VdbePrintSql(Vdbe*);

  FILE *trace;        /* Write an execution trace here, if not NULL */
#endif
  int openedStatement;  /* True if this VM has opened a statement journal */
#ifdef SQLITE_SSE
  int fetchId;          /* Statement number used by sqlite3_fetch_statement */
  int lru;              /* Counter used for LRU cache replacement */
#endif
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
  Vdbe *pLruPrev;
  Vdbe *pLruNext;
#endif
};

/*
** An instance of the following structure holds information about a
** single index record that has already been parsed out into individual
** values.
**
................................................................................
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeOpcodeHasProperty(int, int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeReleaseBuffers(Vdbe *p);

#ifndef NDEBUG
  void sqlite3VdbeMemSanity(Mem*);
#endif
int sqlite3VdbeMemTranslate(Mem*, u8);
#ifdef SQLITE_DEBUG
  void sqlite3VdbePrintSql(Vdbe*);

*************************************************************************
**
** This file contains code use to implement APIs that are part of the
** VDBE.
*/
#include "sqliteInt.h"
#include "vdbeInt.h"



























































































































































/*
** Return TRUE (non-zero) of the statement supplied as an argument needs
** to be recompiled.  A statement needs to be recompiled whenever the
** execution environment changes in a way that would alter the program
** that sqlite3_prepare() generates.  For example, if new functions or
** collating sequences are registered or if an authorizer function is
................................................................................
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
#ifndef SQLITE_MUTEX_NOOP
    sqlite3_mutex *mutex = v->db->mutex;
#endif
    sqlite3_mutex_enter(mutex);

    rc = sqlite3VdbeFinalize(v);
    sqlite3_mutex_leave(mutex);
  }
  return rc;
}

/*
................................................................................
int sqlite3_reset(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3_mutex_enter(v->db->mutex);
    rc = sqlite3VdbeReset(v);

    sqlite3VdbeMakeReady(v, -1, 0, 0, 0);
    assert( (rc & (v->db->errMask))==rc );
    sqlite3_mutex_leave(v->db->mutex);
  }
  return rc;
}

................................................................................
      sqlite3OsCurrentTime(db->pVfs, &rNow);
      p->startTime = (rNow - (int)rNow)*3600.0*24.0*1000000000.0;
    }
#endif

    db->activeVdbeCnt++;
    p->pc = 0;

  }
#ifndef SQLITE_OMIT_EXPLAIN
  if( p->explain ){
    rc = sqlite3VdbeList(p);
  }else
#endif /* SQLITE_OMIT_EXPLAIN */
  {
................................................................................
  if( pStmt ){
    int cnt = 0;
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3 *db = v->db;
    sqlite3_mutex_enter(db->mutex);
    while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
           && cnt++ < 5
           && sqlite3Reprepare(v) ){
      sqlite3_reset(pStmt);
      v->expired = 0;
    }
    if( rc==SQLITE_SCHEMA && v->zSql && db->pErr ){
      /* This case occurs after failing to recompile an sql statement. 
      ** The error message from the SQL compiler has already been loaded 
      ** into the database handle. This block copies the error message 

*************************************************************************
**
** This file contains code use to implement APIs that are part of the
** VDBE.
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
/*
** The following structure contains pointers to the end points of a
** doubly-linked list of all compiled SQL statements that may be holding
** buffers eligible for release when the sqlite3_release_memory() interface is
** invoked. Access to this list is protected by the SQLITE_MUTEX_STATIC_LRU2
** mutex.
**
** Statements are added to the end of this list when sqlite3_reset() is
** called. They are removed either when sqlite3_step() or sqlite3_finalize()
** is called. When statements are added to this list, the associated 
** register array (p->aMem[1..p->nMem]) may contain dynamic buffers that
** can be freed using sqlite3VdbeReleaseMemory().
**
** When statements are added or removed from this list, the mutex
** associated with the Vdbe being added or removed (Vdbe.db->mutex) is
** already held. The LRU2 mutex is then obtained, blocking if necessary,
** the linked-list pointers manipulated and the LRU2 mutex relinquished.
*/
struct StatementLruList {
  Vdbe *pFirst;
  Vdbe *pLast;
};
static struct StatementLruList sqlite3LruStatements;

/*
** Check that the list looks to be internally consistent. This is used
** as part of an assert() statement as follows:
**
**   assert( stmtLruCheck() );
*/
static int stmtLruCheck(){
  Vdbe *p;
  for(p=sqlite3LruStatements.pFirst; p; p=p->pLruNext){
    assert(p->pLruNext || p==sqlite3LruStatements.pLast);
    assert(!p->pLruNext || p->pLruNext->pLruPrev==p);
    assert(p->pLruPrev || p==sqlite3LruStatements.pFirst);
    assert(!p->pLruPrev || p->pLruPrev->pLruNext==p);
  }
  return 1;
}

/*
** Add vdbe p to the end of the statement lru list. It is assumed that
** p is not already part of the list when this is called. The lru list
** is protected by the SQLITE_MUTEX_STATIC_LRU mutex.
*/
static void stmtLruAdd(Vdbe *p){
  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));

  if( p->pLruPrev || p->pLruNext || sqlite3LruStatements.pFirst==p ){
    sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
    return;
  }

  assert( stmtLruCheck() );

  if( !sqlite3LruStatements.pFirst ){
    assert( !sqlite3LruStatements.pLast );
    sqlite3LruStatements.pFirst = p;
    sqlite3LruStatements.pLast = p;
  }else{
    assert( !sqlite3LruStatements.pLast->pLruNext );
    p->pLruPrev = sqlite3LruStatements.pLast;
    sqlite3LruStatements.pLast->pLruNext = p;
    sqlite3LruStatements.pLast = p;
  }

  assert( stmtLruCheck() );

  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
}

/*
** Assuming the SQLITE_MUTEX_STATIC_LRU2 mutext is already held, remove
** statement p from the least-recently-used statement list. If the 
** statement is not currently part of the list, this call is a no-op.
*/
static void stmtLruRemoveNomutex(Vdbe *p){
  if( p->pLruPrev || p->pLruNext || p==sqlite3LruStatements.pFirst ){
    assert( stmtLruCheck() );
    if( p->pLruNext ){
      p->pLruNext->pLruPrev = p->pLruPrev;
    }else{
      sqlite3LruStatements.pLast = p->pLruPrev;
    }
    if( p->pLruPrev ){
      p->pLruPrev->pLruNext = p->pLruNext;
    }else{
      sqlite3LruStatements.pFirst = p->pLruNext;
    }
    p->pLruNext = 0;
    p->pLruPrev = 0;
    assert( stmtLruCheck() );
  }
}

/*
** Assuming the SQLITE_MUTEX_STATIC_LRU2 mutext is not held, remove
** statement p from the least-recently-used statement list. If the 
** statement is not currently part of the list, this call is a no-op.
*/
static void stmtLruRemove(Vdbe *p){
  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
  stmtLruRemoveNomutex(p);
  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
}

/*
** Try to release n bytes of memory by freeing buffers associated 
** with the memory registers of currently unused vdbes.
*/
int sqlite3VdbeReleaseMemory(int n){
  Vdbe *p;
  Vdbe *pNext;
  int nFree = 0;

  sqlite3_mutex_enter(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));
  for(p=sqlite3LruStatements.pFirst; p && nFree<n; p=pNext){
    pNext = p->pLruNext;

    /* For each statement handle in the lru list, attempt to obtain the
    ** associated database mutex. If it cannot be obtained, continue
    ** to the next statement handle. It is not possible to block on
    ** the database mutex - that could cause deadlock.
    */
    if( SQLITE_OK==sqlite3_mutex_try(p->db->mutex) ){
      nFree += sqlite3VdbeReleaseBuffers(p);
      stmtLruRemoveNomutex(p);
      sqlite3_mutex_leave(p->db->mutex);
    }
  }
  sqlite3_mutex_leave(sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU2));

  return nFree;
}

/*
** Call sqlite3Reprepare() on the statement. Remove it from the
** lru list before doing so, as Reprepare() will free all the
** memory register buffers anyway.
*/
int vdbeReprepare(Vdbe *p){
  stmtLruRemove(p);
  return sqlite3Reprepare(p);
}

#else       /* !SQLITE_ENABLE_MEMORY_MANAGEMENT */
  #define stmtLruRemove(x)
  #define stmtLruAdd(x)
  #define vdbeReprepare(x) sqlite3Reprepare(x)
#endif


/*
** Return TRUE (non-zero) of the statement supplied as an argument needs
** to be recompiled.  A statement needs to be recompiled whenever the
** execution environment changes in a way that would alter the program
** that sqlite3_prepare() generates.  For example, if new functions or
** collating sequences are registered or if an authorizer function is
................................................................................
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
#ifndef SQLITE_MUTEX_NOOP
    sqlite3_mutex *mutex = v->db->mutex;
#endif
    sqlite3_mutex_enter(mutex);
    stmtLruRemove(v);
    rc = sqlite3VdbeFinalize(v);
    sqlite3_mutex_leave(mutex);
  }
  return rc;
}

/*
................................................................................
int sqlite3_reset(sqlite3_stmt *pStmt){
  int rc;
  if( pStmt==0 ){
    rc = SQLITE_OK;
  }else{
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3_mutex_enter(v->db->mutex);
    rc = sqlite3VdbeReset(v, 0);
    stmtLruAdd(v);
    sqlite3VdbeMakeReady(v, -1, 0, 0, 0);
    assert( (rc & (v->db->errMask))==rc );
    sqlite3_mutex_leave(v->db->mutex);
  }
  return rc;
}

................................................................................
      sqlite3OsCurrentTime(db->pVfs, &rNow);
      p->startTime = (rNow - (int)rNow)*3600.0*24.0*1000000000.0;
    }
#endif

    db->activeVdbeCnt++;
    p->pc = 0;
    stmtLruRemove(p);
  }
#ifndef SQLITE_OMIT_EXPLAIN
  if( p->explain ){
    rc = sqlite3VdbeList(p);
  }else
#endif /* SQLITE_OMIT_EXPLAIN */
  {
................................................................................
  if( pStmt ){
    int cnt = 0;
    Vdbe *v = (Vdbe*)pStmt;
    sqlite3 *db = v->db;
    sqlite3_mutex_enter(db->mutex);
    while( (rc = sqlite3Step(v))==SQLITE_SCHEMA
           && cnt++ < 5
           && vdbeReprepare(v) ){
      sqlite3_reset(pStmt);
      v->expired = 0;
    }
    if( rc==SQLITE_SCHEMA && v->zSql && db->pErr ){
      /* This case occurs after failing to recompile an sql statement. 
      ** The error message from the SQL compiler has already been loaded 
      ** into the database handle. This block copies the error message 

  fflush(pOut);
}
#endif

/*
** Release an array of N Mem elements
*/
static void releaseMemArray(Mem *p, int N){
  if( p && N ){
    sqlite3 *db = p->db;
    int malloc_failed = db->mallocFailed;
    while( N-->0 ){
      assert( N<2 || p[0].db==p[1].db );

      sqlite3VdbeMemRelease(p);
      p++->flags = MEM_Null;


    }
    db->mallocFailed = malloc_failed;
  }
}


















#ifndef SQLITE_OMIT_EXPLAIN
/*
** Give a listing of the program in the virtual machine.
**
** The interface is the same as sqlite3VdbeExec().  But instead of
** running the code, it invokes the callback once for each instruction.
................................................................................
  assert( db->magic==SQLITE_MAGIC_BUSY );
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );

  /* Even though this opcode does not use dynamic strings for
  ** the result, result columns may become dynamic if the user calls
  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
  */
  releaseMemArray(pMem, p->nMem);

  do{
    i = p->pc++;
  }while( i<p->nOp && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
  if( i>=p->nOp ){
    p->rc = SQLITE_OK;
    rc = SQLITE_DONE;
................................................................................
        p->aMem[n].db = db;
      }
    }
  }
#ifdef SQLITE_DEBUG
  for(n=1; n<p->nMem; n++){
    assert( p->aMem[n].db==db );
    assert( p->aMem[n].flags==MEM_Null );
  }
#endif

  p->pc = -1;
  p->rc = SQLITE_OK;
  p->uniqueCnt = 0;
  p->returnDepth = 0;
................................................................................
/*
** Clean up the VM after execution.
**
** This routine will automatically close any cursors, lists, and/or
** sorters that were left open.  It also deletes the values of
** variables in the aVar[] array.
*/
static void Cleanup(Vdbe *p){
  int i;
  closeAllCursorsExceptActiveVtabs(p);
  for(i=1; i<=p->nMem; i++){
    MemSetTypeFlag(&p->aMem[i], MEM_Null);
  }

  releaseMemArray(&p->aMem[1], p->nMem);
  sqlite3VdbeFifoClear(&p->sFifo);
  if( p->contextStack ){
    for(i=0; i<p->contextStackTop; i++){
      sqlite3VdbeFifoClear(&p->contextStack[i].sFifo);
    }
    sqlite3_free(p->contextStack);
  }
................................................................................
** execution of the vdbe program so that sqlite3_column_count() can
** be called on an SQL statement before sqlite3_step().
*/
void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
  Mem *pColName;
  int n;

  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
  sqlite3_free(p->aColName);
  n = nResColumn*COLNAME_N;
  p->nResColumn = nResColumn;
  p->aColName = pColName = (Mem*)sqlite3DbMallocZero(p->db, sizeof(Mem)*n );
  if( p->aColName==0 ) return;
  while( n-- > 0 ){
    pColName->flags = MEM_Null;
................................................................................
** After this routine is run, the VDBE should be ready to be executed
** again.
**
** To look at it another way, this routine resets the state of the
** virtual machine from VDBE_MAGIC_RUN or VDBE_MAGIC_HALT back to
** VDBE_MAGIC_INIT.
*/
int sqlite3VdbeReset(Vdbe *p){
  sqlite3 *db;
  db = p->db;

  /* If the VM did not run to completion or if it encountered an
  ** error, then it might not have been halted properly.  So halt
  ** it now.
  */
................................................................................
    sqlite3Error(db, p->rc, 0);
    sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, sqlite3_free);
    p->zErrMsg = 0;
  }

  /* Reclaim all memory used by the VDBE
  */
  Cleanup(p);

  /* Save profiling information from this VDBE run.
  */
#ifdef VDBE_PROFILE
  {
    FILE *out = fopen("vdbe_profile.out", "a");
    if( out ){
................................................................................
/*
** Clean up and delete a VDBE after execution.  Return an integer which is
** the result code.  Write any error message text into *pzErrMsg.
*/
int sqlite3VdbeFinalize(Vdbe *p){
  int rc = SQLITE_OK;
  if( p->magic==VDBE_MAGIC_RUN || p->magic==VDBE_MAGIC_HALT ){
    rc = sqlite3VdbeReset(p);
    assert( (rc & p->db->errMask)==rc );
  }else if( p->magic!=VDBE_MAGIC_INIT ){
    return SQLITE_MISUSE;
  }

  sqlite3VdbeDelete(p);
  return rc;
}

/*
** Call the destructor for each auxdata entry in pVdbeFunc for which
** the corresponding bit in mask is clear.  Auxdata entries beyond 31
................................................................................

/*
** Delete an entire VDBE.
*/
void sqlite3VdbeDelete(Vdbe *p){
  int i;
  if( p==0 ) return;
  Cleanup(p);
  if( p->pPrev ){
    p->pPrev->pNext = p->pNext;
  }else{
    assert( p->db->pVdbe==p );
    p->db->pVdbe = p->pNext;
  }
  if( p->pNext ){
................................................................................
      freeP4(pOp->p4type, pOp->p4.p);
#ifdef SQLITE_DEBUG
      sqlite3_free(pOp->zComment);
#endif     
    }
    sqlite3_free(p->aOp);
  }
  releaseMemArray(p->aVar, p->nVar);
  sqlite3_free(p->aLabel);
  if( p->aMem ){
    sqlite3_free(&p->aMem[1]);
  }
  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
  sqlite3_free(p->aColName);
  sqlite3_free(p->zSql);
  p->magic = VDBE_MAGIC_DEAD;
  sqlite3_free(p);
}

/*

  fflush(pOut);
}
#endif

/*
** Release an array of N Mem elements
*/
static void releaseMemArray(Mem *p, int N, int freebuffers){
  if( p && N ){
    sqlite3 *db = p->db;
    int malloc_failed = db->mallocFailed;
    while( N-->0 ){
      assert( N<2 || p[0].db==p[1].db );
      if( freebuffers || p->xDel ){
        sqlite3VdbeMemRelease(p);
        p->flags = MEM_Null;
      }
      p++;
    }
    db->mallocFailed = malloc_failed;
  }
}

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
int sqlite3VdbeReleaseBuffers(Vdbe *p){
  int ii;
  int nFree = 0;
  assert( sqlite3_mutex_held(p->db->mutex) );
  for(ii=1; ii<=p->nMem; ii++){
    Mem *pMem = &p->aMem[ii];
    if( pMem->z && pMem->flags&MEM_Dyn ){
      assert( !pMem->xDel );
      nFree += sqlite3MallocSize(pMem->z);
      sqlite3VdbeMemRelease(pMem);
    }
  }
  return nFree;
}
#endif

#ifndef SQLITE_OMIT_EXPLAIN
/*
** Give a listing of the program in the virtual machine.
**
** The interface is the same as sqlite3VdbeExec().  But instead of
** running the code, it invokes the callback once for each instruction.
................................................................................
  assert( db->magic==SQLITE_MAGIC_BUSY );
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );

  /* Even though this opcode does not use dynamic strings for
  ** the result, result columns may become dynamic if the user calls
  ** sqlite3_column_text16(), causing a translation to UTF-16 encoding.
  */
  releaseMemArray(pMem, p->nMem, 1);

  do{
    i = p->pc++;
  }while( i<p->nOp && p->explain==2 && p->aOp[i].opcode!=OP_Explain );
  if( i>=p->nOp ){
    p->rc = SQLITE_OK;
    rc = SQLITE_DONE;
................................................................................
        p->aMem[n].db = db;
      }
    }
  }
#ifdef SQLITE_DEBUG
  for(n=1; n<p->nMem; n++){
    assert( p->aMem[n].db==db );
    //assert( p->aMem[n].flags==MEM_Null );
  }
#endif

  p->pc = -1;
  p->rc = SQLITE_OK;
  p->uniqueCnt = 0;
  p->returnDepth = 0;
................................................................................
/*
** Clean up the VM after execution.
**
** This routine will automatically close any cursors, lists, and/or
** sorters that were left open.  It also deletes the values of
** variables in the aVar[] array.
*/
static void Cleanup(Vdbe *p, int freebuffers){
  int i;
  closeAllCursorsExceptActiveVtabs(p);
  for(i=1; i<=p->nMem; i++){
    MemSetTypeFlag(&p->aMem[i], MEM_Null);
  }

  releaseMemArray(&p->aMem[1], p->nMem, freebuffers);
  sqlite3VdbeFifoClear(&p->sFifo);
  if( p->contextStack ){
    for(i=0; i<p->contextStackTop; i++){
      sqlite3VdbeFifoClear(&p->contextStack[i].sFifo);
    }
    sqlite3_free(p->contextStack);
  }
................................................................................
** execution of the vdbe program so that sqlite3_column_count() can
** be called on an SQL statement before sqlite3_step().
*/
void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
  Mem *pColName;
  int n;

  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N, 1);
  sqlite3_free(p->aColName);
  n = nResColumn*COLNAME_N;
  p->nResColumn = nResColumn;
  p->aColName = pColName = (Mem*)sqlite3DbMallocZero(p->db, sizeof(Mem)*n );
  if( p->aColName==0 ) return;
  while( n-- > 0 ){
    pColName->flags = MEM_Null;
................................................................................
** After this routine is run, the VDBE should be ready to be executed
** again.
**
** To look at it another way, this routine resets the state of the
** virtual machine from VDBE_MAGIC_RUN or VDBE_MAGIC_HALT back to
** VDBE_MAGIC_INIT.
*/
int sqlite3VdbeReset(Vdbe *p, int freebuffers){
  sqlite3 *db;
  db = p->db;

  /* If the VM did not run to completion or if it encountered an
  ** error, then it might not have been halted properly.  So halt
  ** it now.
  */
................................................................................
    sqlite3Error(db, p->rc, 0);
    sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, sqlite3_free);
    p->zErrMsg = 0;
  }

  /* Reclaim all memory used by the VDBE
  */
  Cleanup(p, freebuffers);

  /* Save profiling information from this VDBE run.
  */
#ifdef VDBE_PROFILE
  {
    FILE *out = fopen("vdbe_profile.out", "a");
    if( out ){
................................................................................
/*
** Clean up and delete a VDBE after execution.  Return an integer which is
** the result code.  Write any error message text into *pzErrMsg.
*/
int sqlite3VdbeFinalize(Vdbe *p){
  int rc = SQLITE_OK;
  if( p->magic==VDBE_MAGIC_RUN || p->magic==VDBE_MAGIC_HALT ){
    rc = sqlite3VdbeReset(p, 1);
    assert( (rc & p->db->errMask)==rc );
  }else if( p->magic!=VDBE_MAGIC_INIT ){
    return SQLITE_MISUSE;
  }
  releaseMemArray(&p->aMem[1], p->nMem, 1);
  sqlite3VdbeDelete(p);
  return rc;
}

/*
** Call the destructor for each auxdata entry in pVdbeFunc for which
** the corresponding bit in mask is clear.  Auxdata entries beyond 31
................................................................................

/*
** Delete an entire VDBE.
*/
void sqlite3VdbeDelete(Vdbe *p){
  int i;
  if( p==0 ) return;
  Cleanup(p, 1);
  if( p->pPrev ){
    p->pPrev->pNext = p->pNext;
  }else{
    assert( p->db->pVdbe==p );
    p->db->pVdbe = p->pNext;
  }
  if( p->pNext ){
................................................................................
      freeP4(pOp->p4type, pOp->p4.p);
#ifdef SQLITE_DEBUG
      sqlite3_free(pOp->zComment);
#endif     
    }
    sqlite3_free(p->aOp);
  }
  releaseMemArray(p->aVar, p->nVar, 1);
  sqlite3_free(p->aLabel);
  if( p->aMem ){
    sqlite3_free(&p->aMem[1]);
  }
  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N, 1);
  sqlite3_free(p->aColName);
  sqlite3_free(p->zSql);
  p->magic = VDBE_MAGIC_DEAD;
  sqlite3_free(p);
}

/*