SQLite

  sqlite3_int64 iStartLeaf,       /* First leaf to traverse */
  sqlite3_int64 iEndLeaf,         /* Final leaf to traverse */
  sqlite3_int64 iEndBlock,        /* Final block of segment */
  const char *zRoot,              /* Buffer containing root node */
  int nRoot,                      /* Size of buffer containing root node */
  Fts3SegReader **ppReader        /* OUT: Allocated Fts3SegReader */
){

  Fts3SegReader *pReader;         /* Newly allocated SegReader object */
  int nExtra = 0;                 /* Bytes to allocate segment root node */

  assert( iStartLeaf<=iEndLeaf );
  if( iStartLeaf==0 ){
    nExtra = nRoot + FTS3_NODE_PADDING;
  }

    pReader->aNode = (char *)&pReader[1];
    pReader->nNode = nRoot;
    memcpy(pReader->aNode, zRoot, nRoot);
    memset(&pReader->aNode[nRoot], 0, FTS3_NODE_PADDING);
  }else{
    pReader->iCurrentBlock = iStartLeaf-1;
  }


  *ppReader = pReader;



  return SQLITE_OK;
}

/*
** This is a comparison function used as a qsort() callback when sorting
** an array of pending terms by term. This occurs as part of flushing
** the contents of the pending-terms hash table to the database.
*/

  Fts3Table *p,                   /* Virtual table handle */
  const char *zTerm,              /* Term to search for */
  int nTerm,                      /* Size of buffer zTerm */
  int isPrefix,                   /* True for a term-prefix query */
  Fts3SegReader **ppReader        /* OUT: SegReader for pending-terms */
){
  Fts3SegReader *pReader = 0;     /* Fts3SegReader object to return */
  Fts3HashElem *pE;               /* Iterator variable */
  Fts3HashElem **aElem = 0;       /* Array of term hash entries to scan */
  int nElem = 0;                  /* Size of array at aElem */
  int rc = SQLITE_OK;             /* Return Code */

  if( isPrefix ){
    int nAlloc = 0;               /* Size of allocated array at aElem */


    for(pE=fts3HashFirst(&p->pendingTerms); pE; pE=fts3HashNext(pE)){
      char *zKey = (char *)fts3HashKey(pE);
      int nKey = fts3HashKeysize(pE);
      if( nTerm==0 || (nKey>=nTerm && 0==memcmp(zKey, zTerm, nTerm)) ){
        if( nElem==nAlloc ){
          Fts3HashElem **aElem2;

*/
static int deserializeGeometry(sqlite3_value *pValue, RtreeConstraint *pCons){
  RtreeMatchArg *p;
  sqlite3_rtree_geometry *pGeom;
  int nBlob;

  /* Check that value is actually a blob. */
  if( sqlite3_value_type(pValue)!=SQLITE_BLOB ) return SQLITE_ERROR;

  /* Check that the blob is roughly the right size. */
  nBlob = sqlite3_value_bytes(pValue);
  if( nBlob<(int)sizeof(RtreeMatchArg) 
   || ((nBlob-sizeof(RtreeMatchArg))%sizeof(double))!=0
  ){
    return SQLITE_ERROR;

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

** as heap memory usages approaches the limit.
** ^The soft heap limit is "soft" because even though SQLite strives to stay
** below the limit, it will exceed the limit rather than generate
** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
** is advisory only.
**
** ^The return value from sqlite3_soft_heap_limit64() is the size of
** the soft heap limit prior to the call, or negative in the case of an
** error.  ^If the argument N is negative
** then no change is made to the soft heap limit.  Hence, the current
** size of the soft heap limit can be determined by invoking
** sqlite3_soft_heap_limit64() with a negative argument.
**
** ^If the argument N is zero then the soft heap limit is disabled.
**
** ^(The soft heap limit is not enforced in the current implementation

/*
** 2010 May 05
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    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 implementation of the Tcl [testvfs] command,
** used to create SQLite VFS implementations with various properties and
** instrumentation to support testing SQLite.
**
**   testvfs VFSNAME ?OPTIONS?
**
** Available options are:
**
**   -noshm      BOOLEAN        (True to omit shm methods. Default false)
**   -default    BOOLEAN        (True to make the vfs default. Default false)
**   -szosfile   INTEGER        (Value for sqlite3_vfs.szOsFile)
**   -mxpathname INTEGER        (Value for sqlite3_vfs.mxPathname)
**   -iversion   INTEGER        (Value for sqlite3_vfs.iVersion)
*/
#if SQLITE_TEST          /* This file is used for testing only */

#include "sqlite3.h"
#include "sqliteInt.h"

typedef struct Testvfs Testvfs;
typedef struct TestvfsShm TestvfsShm;
typedef struct TestvfsBuffer TestvfsBuffer;

*/
struct Testvfs {
  char *zName;                    /* Name of this VFS */
  sqlite3_vfs *pParent;           /* The VFS to use for file IO */
  sqlite3_vfs *pVfs;              /* The testvfs registered with SQLite */
  Tcl_Interp *interp;             /* Interpreter to run script in */
  Tcl_Obj *pScript;               /* Script to execute */


  TestvfsBuffer *pBuffer;         /* List of shared buffers */
  int isNoshm;

  int mask;                       /* Mask controlling [script] and [ioerr] */

  TestFaultInject ioerr_err;
  TestFaultInject full_err;

** The Testvfs.mask variable is set to a combination of the following.
** If a bit is clear in Testvfs.mask, then calls made by SQLite to the 
** corresponding VFS method is ignored for purposes of:
**
**   + Simulating IO errors, and
**   + Invoking the Tcl callback script.
*/
#define TESTVFS_SHMOPEN_MASK      0x00000001
#define TESTVFS_SHMLOCK_MASK      0x00000010
#define TESTVFS_SHMMAP_MASK       0x00000020
#define TESTVFS_SHMBARRIER_MASK   0x00000040
#define TESTVFS_SHMCLOSE_MASK     0x00000080

#define TESTVFS_OPEN_MASK         0x00000100
#define TESTVFS_SYNC_MASK         0x00000200
#define TESTVFS_DELETE_MASK       0x00000400
#define TESTVFS_CLOSE_MASK        0x00000800
#define TESTVFS_WRITE_MASK        0x00001000
#define TESTVFS_TRUNCATE_MASK     0x00002000
#define TESTVFS_ACCESS_MASK       0x00004000
#define TESTVFS_FULLPATHNAME_MASK 0x00008000
#define TESTVFS_READ_MASK         0x00010000

#define TESTVFS_ALL_MASK          0x0001FFFF


#define TESTVFS_MAX_PAGES 1024

/*
** A shared-memory buffer. There is one of these objects for each shared
** memory region opened by clients. If two clients open the same file,

  Testvfs *p, 
  const char *zMethod,
  Tcl_Obj *arg1,
  Tcl_Obj *arg2,
  Tcl_Obj *arg3
){
  int rc;                         /* Return code from Tcl_EvalObj() */


  Tcl_Obj *pEval;

  assert( p->pScript );







  assert( zMethod );









  assert( p );


  assert( arg2==0 || arg1!=0 );
  assert( arg3==0 || arg2!=0 );

  pEval = Tcl_DuplicateObj(p->pScript);
  Tcl_IncrRefCount(p->pScript);
  Tcl_ListObjAppendElement(p->interp, pEval, Tcl_NewStringObj(zMethod, -1));
  if( arg1 ) Tcl_ListObjAppendElement(p->interp, pEval, arg1);
  if( arg2 ) Tcl_ListObjAppendElement(p->interp, pEval, arg2);
  if( arg3 ) Tcl_ListObjAppendElement(p->interp, pEval, arg3);

  rc = Tcl_EvalObjEx(p->interp, pEval, TCL_EVAL_GLOBAL);

  if( rc!=TCL_OK ){
    Tcl_BackgroundError(p->interp);
    Tcl_ResetResult(p->interp);
  }





}


/*
** Close an tvfs-file.
*/
static int tvfsClose(sqlite3_file *pFile){

*/
static int tvfsRead(
  sqlite3_file *pFile, 
  void *zBuf, 
  int iAmt, 
  sqlite_int64 iOfst
){
  int rc = SQLITE_OK;
  TestvfsFd *pFd = tvfsGetFd(pFile);
  Testvfs *p = (Testvfs *)pFd->pVfs->pAppData;
  if( p->pScript && p->mask&TESTVFS_READ_MASK ){
    tvfsExecTcl(p, "xRead", 
        Tcl_NewStringObj(pFd->zFilename, -1), pFd->pShmId, 0
    );
    tvfsResultCode(p, &rc);
  }
  if( rc==SQLITE_OK && p->mask&TESTVFS_READ_MASK && tvfsInjectIoerr(p) ){
    rc = SQLITE_IOERR;
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3OsRead(pFd->pReal, zBuf, iAmt, iOfst);
  }
  return rc;
}

/*
** Write data to an tvfs-file.
*/
static int tvfsWrite(
  sqlite3_file *pFile, 

  pFd->pVfs = pVfs;
  pFd->pReal = (sqlite3_file *)&pFd[1];
  memset(pTestfile, 0, sizeof(TestvfsFile));
  pTestfile->pFd = pFd;

  /* Evaluate the Tcl script: 
  **
  **   SCRIPT xOpen FILENAME KEY-VALUE-ARGS
  **
  ** If the script returns an SQLite error code other than SQLITE_OK, an
  ** error is returned to the caller. If it returns SQLITE_OK, the new
  ** connection is named "anon". Otherwise, the value returned by the
  ** script is used as the connection name.
  */
  Tcl_ResetResult(p->interp);
  if( p->pScript && p->mask&TESTVFS_OPEN_MASK ){
    Tcl_Obj *pArg = Tcl_NewObj();
    Tcl_IncrRefCount(pArg);
    if( flags&SQLITE_OPEN_MAIN_DB ){
      const char *z = &zName[strlen(zName)+1];
      while( *z ){
        Tcl_ListObjAppendElement(0, pArg, Tcl_NewStringObj(z, -1));
        z += strlen(z) + 1;
        Tcl_ListObjAppendElement(0, pArg, Tcl_NewStringObj(z, -1));
        z += strlen(z) + 1;
      }
    }
    tvfsExecTcl(p, "xOpen", Tcl_NewStringObj(pFd->zFilename, -1), pArg, 0);
    Tcl_DecrRefCount(pArg);
    if( tvfsResultCode(p, &rc) ){
      if( rc!=SQLITE_OK ) return rc;
    }else{
      pId = Tcl_GetObjResult(p->interp);
    }
  }

*/
static int tvfsFullPathname(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int nOut, 
  char *zOut
){
  Testvfs *p = (Testvfs *)pVfs->pAppData;
  if( p->pScript && p->mask&TESTVFS_FULLPATHNAME_MASK ){
    int rc;
    tvfsExecTcl(p, "xFullPathname", Tcl_NewStringObj(zPath, -1), 0, 0);
    if( tvfsResultCode(p, &rc) ){
      if( rc!=SQLITE_OK ) return rc;
    }
  }
  return sqlite3OsFullPathname(PARENTVFS(pVfs), zPath, nOut, zOut);
}

#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Open the dynamic library located at zPath and return a handle.
*/

    return TCL_ERROR;
  }
  Tcl_ResetResult(interp);

  switch( aSubcmd[i].eCmd ){
    case CMD_SHM: {
      Tcl_Obj *pObj;
      int i, rc;
      TestvfsBuffer *pBuffer;
      char *zName;
      if( objc!=3 && objc!=4 ){
        Tcl_WrongNumArgs(interp, 2, objv, "FILE ?VALUE?");
        return TCL_ERROR;
      }
      zName = ckalloc(p->pParent->mxPathname);
      rc = p->pParent->xFullPathname(
          p->pParent, Tcl_GetString(objv[2]), 
          p->pParent->mxPathname, zName
      );
      if( rc!=SQLITE_OK ){
        Tcl_AppendResult(interp, "failed to get full path: ",
                         Tcl_GetString(objv[2]), 0);
        ckfree(zName);
        return TCL_ERROR;
      }
      for(pBuffer=p->pBuffer; pBuffer; pBuffer=pBuffer->pNext){
        if( 0==strcmp(pBuffer->zFile, zName) ) break;
      }
      ckfree(zName);
      if( !pBuffer ){
        Tcl_AppendResult(interp, "no such file: ", Tcl_GetString(objv[2]), 0);
        return TCL_ERROR;

    }

    case CMD_FILTER: {
      static struct VfsMethod {
        char *zName;
        int mask;
      } vfsmethod [] = {
        { "xShmOpen",      TESTVFS_SHMOPEN_MASK },
        { "xShmLock",      TESTVFS_SHMLOCK_MASK },
        { "xShmBarrier",   TESTVFS_SHMBARRIER_MASK },
        { "xShmUnmap",     TESTVFS_SHMCLOSE_MASK },
        { "xShmMap",       TESTVFS_SHMMAP_MASK },
        { "xSync",         TESTVFS_SYNC_MASK },
        { "xDelete",       TESTVFS_DELETE_MASK },
        { "xWrite",        TESTVFS_WRITE_MASK },
        { "xRead",         TESTVFS_READ_MASK },
        { "xTruncate",     TESTVFS_TRUNCATE_MASK },
        { "xOpen",         TESTVFS_OPEN_MASK },
        { "xClose",        TESTVFS_CLOSE_MASK },
        { "xAccess",       TESTVFS_ACCESS_MASK },
        { "xFullPathname", TESTVFS_FULLPATHNAME_MASK },
      };
      Tcl_Obj **apElem = 0;
      int nElem = 0;
      int i;
      int mask = 0;
      if( objc!=3 ){
        Tcl_WrongNumArgs(interp, 2, objv, "LIST");

    }

    case CMD_SCRIPT: {
      if( objc==3 ){
        int nByte;
        if( p->pScript ){
          Tcl_DecrRefCount(p->pScript);



          p->pScript = 0;
        }
        Tcl_GetStringFromObj(objv[2], &nByte);
        if( nByte>0 ){
          p->pScript = Tcl_DuplicateObj(objv[2]);
          Tcl_IncrRefCount(p->pScript);
        }

  return TCL_OK;
}

static void testvfs_obj_del(ClientData cd){
  Testvfs *p = (Testvfs *)cd;
  if( p->pScript ) Tcl_DecrRefCount(p->pScript);
  sqlite3_vfs_unregister(p->pVfs);

  ckfree((char *)p->pVfs);
  ckfree((char *)p);
}

/*
** Usage:  testvfs VFSNAME ?SWITCHES?
**

#-------------------------------------------------------------------------
# Check that it is not possible to open a database file if the full path
# to the associated journal file will be longer than sqlite3_vfs.mxPathname.
#
testvfs tv -default 1
tv script xOpenCb
tv filter xOpen
proc xOpenCb {method filename args} {
  set ::file_len [string length $filename]
}
sqlite3 db test.db
db close
tv delete

for {set ii [expr $::file_len-5]} {$ii < [expr $::file_len+20]} {incr ii} {