# same unless your are cross-compiling.)
#
TCC = @CC@ @CPPFLAGS@ @CFLAGS@ -I. -I${TOP}/src -I${TOP}/ext/rtree

# Define this for the autoconf-based build, so that the code knows it can
# include the generated config.h
# 
TCC += -D_HAVE_SQLITE_CONFIG_H

# Define -DNDEBUG to compile without debugging (i.e., for production usage)
# Omitting the define will cause extra debugging code to be inserted and
# includes extra comments when "EXPLAIN stmt" is used.
#
TCC += @TARGET_DEBUG@ @XTHREADCONNECT@

# same unless your are cross-compiling.)
#
TCC = @CC@ @CPPFLAGS@ @CFLAGS@ -I. -I${TOP}/src -I${TOP}/ext/rtree

# Define this for the autoconf-based build, so that the code knows it can
# include the generated config.h
# 
TCC += -D_HAVE_SQLITE_CONFIG_H -DBUILD_sqlite

# Define -DNDEBUG to compile without debugging (i.e., for production usage)
# Omitting the define will cause extra debugging code to be inserted and
# includes extra comments when "EXPLAIN stmt" is used.
#
TCC += @TARGET_DEBUG@ @XTHREADCONNECT@

** Class derived from sqlite3_tokenizer
*/
typedef struct porter_tokenizer {
  sqlite3_tokenizer base;      /* Base class */
} porter_tokenizer;

/*
** Class derived from sqlit3_tokenizer_cursor
*/
typedef struct porter_tokenizer_cursor {
  sqlite3_tokenizer_cursor base;
  const char *zInput;          /* input we are tokenizing */
  int nInput;                  /* size of the input */
  int iOffset;                 /* current position in zInput */
  int iToken;                  /* index of next token to be returned */

** Class derived from sqlite3_tokenizer
*/
typedef struct porter_tokenizer {
  sqlite3_tokenizer base;      /* Base class */
} porter_tokenizer;

/*
** Class derived from sqlite3_tokenizer_cursor
*/
typedef struct porter_tokenizer_cursor {
  sqlite3_tokenizer_cursor base;
  const char *zInput;          /* input we are tokenizing */
  int nInput;                  /* size of the input */
  int iOffset;                 /* current position in zInput */
  int iToken;                  /* index of next token to be returned */

   $(TOP)/src/sqliteLimit.h \
   $(TOP)/src/vdbe.h \
   $(TOP)/src/vdbeInt.h

# Header files used by extensions
#
EXTHDR += \
  $(TOP)/ext/fts1/fts1.h \
  $(TOP)/ext/fts1/fts1_hash.h \
  $(TOP)/ext/fts1/fts1_tokenizer.h
EXTHDR += \
  $(TOP)/ext/fts2/fts2.h \
  $(TOP)/ext/fts2/fts2_hash.h \
  $(TOP)/ext/fts2/fts2_tokenizer.h
EXTHDR += \
  $(TOP)/ext/fts3/fts3.h \
  $(TOP)/ext/fts3/fts3Int.h \
  $(TOP)/ext/fts3/fts3_hash.h \
  $(TOP)/ext/fts3/fts3_tokenizer.h
EXTHDR += \
  $(TOP)/ext/rtree/rtree.h
EXTHDR += \
  $(TOP)/ext/icu/sqliteicu.h
EXTHDR += \
  $(TOP)/ext/sqlrr/sqlrr.h

# This is the default Makefile target.  The objects listed here
# are what get build when you type just "make" with no arguments.
#
all:	sqlite3.h libsqlite3.a sqlite3$(EXE)

   $(TOP)/src/sqliteLimit.h \
   $(TOP)/src/vdbe.h \
   $(TOP)/src/vdbeInt.h

# Header files used by extensions
#
EXTHDR += \

















  $(TOP)/ext/sqlrr/sqlrr.h

# This is the default Makefile target.  The objects listed here
# are what get build when you type just "make" with no arguments.
#
all:	sqlite3.h libsqlite3.a sqlite3$(EXE)

  sqlite3BtreeEnter(pTo);
  sqlite3BtreeEnter(pFrom);

  assert( sqlite3BtreeIsInTrans(pTo) );
  pFd = sqlite3PagerFile(sqlite3BtreePager(pTo));
  if( pFd->pMethods ){
    i64 nByte = sqlite3BtreeGetPageSize(pFrom)*(i64)sqlite3BtreeLastPage(pFrom);
    sqlite3BeginBenignMalloc();
    sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte);

    sqlite3EndBenignMalloc();
  }

  /* Set up an sqlite3_backup object. sqlite3_backup.pDestDb must be set
  ** to 0. This is used by the implementations of sqlite3_backup_step()
  ** and sqlite3_backup_finish() to detect that they are being called
  ** from this function, not directly by the user.
  */
................................................................................
  ** checks this assumption - (p->rc) should be set to either SQLITE_DONE 
  ** or an error code.
  */
  sqlite3_backup_step(&b, 0x7FFFFFFF);
  assert( b.rc!=SQLITE_OK );
  rc = sqlite3_backup_finish(&b);
  if( rc==SQLITE_OK ){
    pTo->pBt->pageSizeFixed = 0;
  }else{
    sqlite3PagerClearCache(sqlite3BtreePager(b.pDest));
  }

  assert( sqlite3BtreeIsInTrans(pTo)==0 );

  sqlite3BtreeLeave(pFrom);
  sqlite3BtreeLeave(pTo);
  return rc;
}
#endif /* SQLITE_OMIT_VACUUM */

  sqlite3BtreeEnter(pTo);
  sqlite3BtreeEnter(pFrom);

  assert( sqlite3BtreeIsInTrans(pTo) );
  pFd = sqlite3PagerFile(sqlite3BtreePager(pTo));
  if( pFd->pMethods ){
    i64 nByte = sqlite3BtreeGetPageSize(pFrom)*(i64)sqlite3BtreeLastPage(pFrom);

    rc = sqlite3OsFileControl(pFd, SQLITE_FCNTL_OVERWRITE, &nByte);
    if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK;
    if( rc ) goto copy_finished;
  }

  /* Set up an sqlite3_backup object. sqlite3_backup.pDestDb must be set
  ** to 0. This is used by the implementations of sqlite3_backup_step()
  ** and sqlite3_backup_finish() to detect that they are being called
  ** from this function, not directly by the user.
  */
................................................................................
  ** checks this assumption - (p->rc) should be set to either SQLITE_DONE 
  ** or an error code.
  */
  sqlite3_backup_step(&b, 0x7FFFFFFF);
  assert( b.rc!=SQLITE_OK );
  rc = sqlite3_backup_finish(&b);
  if( rc==SQLITE_OK ){
    pTo->pBt->btsFlags &= ~BTS_PAGESIZE_FIXED;
  }else{
    sqlite3PagerClearCache(sqlite3BtreePager(b.pDest));
  }

  assert( sqlite3BtreeIsInTrans(pTo)==0 );
copy_finished:
  sqlite3BtreeLeave(pFrom);
  sqlite3BtreeLeave(pTo);
  return rc;
}
#endif /* SQLITE_OMIT_VACUUM */

  if( !p->sharable ){
    return SQLITE_OK;
  }

  /* If some other connection is holding an exclusive lock, the
  ** requested lock may not be obtained.
  */
  if( pBt->pWriter!=p && pBt->isExclusive ){
    sqlite3ConnectionBlocked(p->db, pBt->pWriter->db);
    return SQLITE_LOCKED_SHAREDCACHE;
  }

  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
    /* The condition (pIter->eLock!=eLock) in the following if(...) 
    ** statement is a simplification of:
................................................................................
    */
    assert( pIter->eLock==READ_LOCK || pIter->eLock==WRITE_LOCK );
    assert( eLock==READ_LOCK || pIter->pBtree==p || pIter->eLock==READ_LOCK);
    if( pIter->pBtree!=p && pIter->iTable==iTab && pIter->eLock!=eLock ){
      sqlite3ConnectionBlocked(p->db, pIter->pBtree->db);
      if( eLock==WRITE_LOCK ){
        assert( p==pBt->pWriter );
        pBt->isPending = 1;
      }
      return SQLITE_LOCKED_SHAREDCACHE;
    }
  }
  return SQLITE_OK;
}
#endif /* !SQLITE_OMIT_SHARED_CACHE */
................................................................................

#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** Release all the table locks (locks obtained via calls to
** the setSharedCacheTableLock() procedure) held by Btree object p.
**
** This function assumes that Btree p has an open read or write 
** transaction. If it does not, then the BtShared.isPending variable
** may be incorrectly cleared.
*/
static void clearAllSharedCacheTableLocks(Btree *p){
  BtShared *pBt = p->pBt;
  BtLock **ppIter = &pBt->pLock;

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( p->sharable || 0==*ppIter );
  assert( p->inTrans>0 );

  while( *ppIter ){
    BtLock *pLock = *ppIter;
    assert( pBt->isExclusive==0 || pBt->pWriter==pLock->pBtree );
    assert( pLock->pBtree->inTrans>=pLock->eLock );
    if( pLock->pBtree==p ){
      *ppIter = pLock->pNext;
      assert( pLock->iTable!=1 || pLock==&p->lock );
      if( pLock->iTable!=1 ){
        sqlite3_free(pLock);
      }
    }else{
      ppIter = &pLock->pNext;
    }
  }

  assert( pBt->isPending==0 || pBt->pWriter );
  if( pBt->pWriter==p ){
    pBt->pWriter = 0;
    pBt->isExclusive = 0;
    pBt->isPending = 0;
  }else if( pBt->nTransaction==2 ){
    /* This function is called when Btree p is concluding its 
    ** transaction. If there currently exists a writer, and p is not
    ** that writer, then the number of locks held by connections other
    ** than the writer must be about to drop to zero. In this case
    ** set the isPending flag to 0.
    **
    ** If there is not currently a writer, then BtShared.isPending must
    ** be zero already. So this next line is harmless in that case.
    */
    pBt->isPending = 0;
  }
}

/*
** This function changes all write-locks held by Btree p into read-locks.
*/
static void downgradeAllSharedCacheTableLocks(Btree *p){
  BtShared *pBt = p->pBt;
  if( pBt->pWriter==p ){
    BtLock *pLock;
    pBt->pWriter = 0;
    pBt->isExclusive = 0;
    pBt->isPending = 0;
    for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
      assert( pLock->eLock==READ_LOCK || pLock->pBtree==p );
      pLock->eLock = READ_LOCK;
    }
  }
}

................................................................................
  assert( pPage->pBt!=0 );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( start>=pPage->hdrOffset+6+pPage->childPtrSize );
  assert( (start + size) <= (int)pPage->pBt->usableSize );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( size>=0 );   /* Minimum cell size is 4 */

  if( pPage->pBt->secureDelete ){
    /* Overwrite deleted information with zeros when the secure_delete
    ** option is enabled */
    memset(&data[start], 0, size);
  }

  /* Add the space back into the linked list of freeblocks.  Note that
  ** even though the freeblock list was checked by btreeInitPage(),
................................................................................
    pPage->intKey = 0;
    pPage->hasData = 0;
    pPage->maxLocal = pBt->maxLocal;
    pPage->minLocal = pBt->minLocal;
  }else{
    return SQLITE_CORRUPT_BKPT;
  }

  return SQLITE_OK;
}

/*
** Initialize the auxiliary information for a disk block.
**
** Return SQLITE_OK on success.  If we see that the page does
................................................................................
  u16 first;

  assert( sqlite3PagerPagenumber(pPage->pDbPage)==pPage->pgno );
  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
  assert( sqlite3PagerGetData(pPage->pDbPage) == data );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pBt->secureDelete ){
    memset(&data[hdr], 0, pBt->usableSize - hdr);
  }
  data[hdr] = (char)flags;
  first = hdr + 8 + 4*((flags&PTF_LEAF)==0 ?1:0);
  memset(&data[hdr+1], 0, 4);
  data[hdr+7] = 0;
  put2byte(&data[hdr+5], pBt->usableSize);
................................................................................
    pBt->openFlags = (u8)flags;
    pBt->db = db;
    sqlite3PagerSetBusyhandler(pBt->pPager, btreeInvokeBusyHandler, pBt);
    p->pBt = pBt;
  
    pBt->pCursor = 0;
    pBt->pPage1 = 0;
    pBt->readOnly = sqlite3PagerIsreadonly(pBt->pPager);
#ifdef SQLITE_SECURE_DELETE
    pBt->secureDelete = 1;
#endif
    pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
    if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
         || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
      pBt->pageSize = 0;
#ifndef SQLITE_OMIT_AUTOVACUUM
      /* If the magic name ":memory:" will create an in-memory database, then
................................................................................
        pBt->autoVacuum = (SQLITE_DEFAULT_AUTOVACUUM ? 1 : 0);
        pBt->incrVacuum = (SQLITE_DEFAULT_AUTOVACUUM==2 ? 1 : 0);
      }
#endif
      nReserve = 0;
    }else{
      nReserve = zDbHeader[20];
      pBt->pageSizeFixed = 1;
#ifndef SQLITE_OMIT_AUTOVACUUM
      pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
      pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
#endif
    }
    rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
    if( rc ) goto btree_open_out;
................................................................................
** of the database file used for locking (beginning at PENDING_BYTE,
** the first byte past the 1GB boundary, 0x40000000) needs to occur
** at the beginning of a page.
**
** If parameter nReserve is less than zero, then the number of reserved
** bytes per page is left unchanged.
**
** If the iFix!=0 then the pageSizeFixed flag is set so that the page size
** and autovacuum mode can no longer be changed.
*/
int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
  int rc = SQLITE_OK;
  BtShared *pBt = p->pBt;
  assert( nReserve>=-1 && nReserve<=255 );
  sqlite3BtreeEnter(p);
  if( pBt->pageSizeFixed ){
    sqlite3BtreeLeave(p);
    return SQLITE_READONLY;
  }
  if( nReserve<0 ){
    nReserve = pBt->pageSize - pBt->usableSize;
  }
  assert( nReserve>=0 && nReserve<=255 );
................................................................................
    assert( (pageSize & 7)==0 );
    assert( !pBt->pPage1 && !pBt->pCursor );
    pBt->pageSize = (u32)pageSize;
    freeTempSpace(pBt);
  }
  rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
  pBt->usableSize = pBt->pageSize - (u16)nReserve;
  if( iFix ) pBt->pageSizeFixed = 1;
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** Return the currently defined page size
*/
................................................................................
  sqlite3BtreeEnter(p);
  n = sqlite3PagerMaxPageCount(p->pBt->pPager, mxPage);
  sqlite3BtreeLeave(p);
  return n;
}

/*
** Set the secureDelete flag if newFlag is 0 or 1.  If newFlag is -1,
** then make no changes.  Always return the value of the secureDelete
** setting after the change.
*/
int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
  int b;
  if( p==0 ) return 0;
  sqlite3BtreeEnter(p);
  if( newFlag>=0 ){
    p->pBt->secureDelete = (newFlag!=0) ? 1 : 0;

  } 
  b = p->pBt->secureDelete;

  sqlite3BtreeLeave(p);
  return b;
}
#endif /* !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM) */

/*
** Change the 'auto-vacuum' property of the database. If the 'autoVacuum'
................................................................................
  return SQLITE_READONLY;
#else
  BtShared *pBt = p->pBt;
  int rc = SQLITE_OK;
  u8 av = (u8)autoVacuum;

  sqlite3BtreeEnter(p);
  if( pBt->pageSizeFixed && (av ?1:0)!=pBt->autoVacuum ){
    rc = SQLITE_READONLY;
  }else{
    pBt->autoVacuum = av ?1:0;
    pBt->incrVacuum = av==2 ?1:0;
  }
  sqlite3BtreeLeave(p);
  return rc;
................................................................................
    rc = SQLITE_NOTADB;
    if( memcmp(page1, zMagicHeader, 16)!=0 ){
      goto page1_init_failed;
    }

#ifdef SQLITE_OMIT_WAL
    if( page1[18]>1 ){
      pBt->readOnly = 1;
    }
    if( page1[19]>1 ){
      goto page1_init_failed;
    }
#else
    if( page1[18]>2 ){
      pBt->readOnly = 1;
    }
    if( page1[19]>2 ){
      goto page1_init_failed;
    }

    /* If the write version is set to 2, this database should be accessed
    ** in WAL mode. If the log is not already open, open it now. Then 
    ** return SQLITE_OK and return without populating BtShared.pPage1.
    ** The caller detects this and calls this function again. This is
    ** required as the version of page 1 currently in the page1 buffer
    ** may not be the latest version - there may be a newer one in the log
    ** file.
    */
    if( page1[19]==2 && pBt->doNotUseWAL==0 ){
      int isOpen = 0;
      rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
      if( rc!=SQLITE_OK ){
        goto page1_init_failed;
      }else if( isOpen==0 ){
#ifdef SQLITE_DEFAULT_WAL_SAFETYLEVEL
        /* Default to specified safety_level for WAL mode */
................................................................................
  ** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
  ** page pointer.
  */
  pBt->maxLocal = (u16)((pBt->usableSize-12)*64/255 - 23);
  pBt->minLocal = (u16)((pBt->usableSize-12)*32/255 - 23);
  pBt->maxLeaf = (u16)(pBt->usableSize - 35);
  pBt->minLeaf = (u16)((pBt->usableSize-12)*32/255 - 23);





  assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
  pBt->pPage1 = pPage1;
  pBt->nPage = nPage;
  return SQLITE_OK;

page1_init_failed:
  releasePage(pPage1);
................................................................................
  assert( pBt->usableSize<=pBt->pageSize && pBt->usableSize+255>=pBt->pageSize);
  data[20] = (u8)(pBt->pageSize - pBt->usableSize);
  data[21] = 64;
  data[22] = 32;
  data[23] = 32;
  memset(&data[24], 0, 100-24);
  zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
  pBt->pageSizeFixed = 1;
#ifndef SQLITE_OMIT_AUTOVACUUM
  assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
  assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
  put4byte(&data[36 + 4*4], pBt->autoVacuum);
  put4byte(&data[36 + 7*4], pBt->incrVacuum);
#endif
  pBt->nPage = 1;
................................................................................
  ** is requested, this is a no-op.
  */
  if( p->inTrans==TRANS_WRITE || (p->inTrans==TRANS_READ && !wrflag) ){
    goto trans_begun;
  }

  /* Write transactions are not possible on a read-only database */
  if( pBt->readOnly && wrflag ){
    rc = SQLITE_READONLY;
    goto trans_begun;
  }

#ifndef SQLITE_OMIT_SHARED_CACHE
  /* If another database handle has already opened a write transaction 
  ** on this shared-btree structure and a second write transaction is
  ** requested, return SQLITE_LOCKED.
  */
  if( (wrflag && pBt->inTransaction==TRANS_WRITE) || pBt->isPending ){


    pBlock = pBt->pWriter->db;
  }else if( wrflag>1 ){
    BtLock *pIter;
    for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
      if( pIter->pBtree!=p ){
        pBlock = pIter->pBtree->db;
        break;
................................................................................

  /* Any read-only or read-write transaction implies a read-lock on 
  ** page 1. So if some other shared-cache client already has a write-lock 
  ** on page 1, the transaction cannot be opened. */
  rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
  if( SQLITE_OK!=rc ) goto trans_begun;

  pBt->initiallyEmpty = (u8)(pBt->nPage==0);

  do {
    /* Call lockBtree() until either pBt->pPage1 is populated or
    ** lockBtree() returns something other than SQLITE_OK. lockBtree()
    ** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
    ** reading page 1 it discovers that the page-size of the database 
    ** file is not pBt->pageSize. In this case lockBtree() will update
    ** pBt->pageSize to the page-size of the file on disk.
    */
    while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );

    if( rc==SQLITE_OK && wrflag ){
      if( pBt->readOnly ){
        rc = SQLITE_READONLY;
      }else{
        rc = sqlite3PagerBegin(pBt->pPager,wrflag>1,sqlite3TempInMemory(p->db));
        if( rc==SQLITE_OK ){
          rc = newDatabase(pBt);
        }
      }
................................................................................
      pBt->inTransaction = p->inTrans;
    }
    if( wrflag ){
      MemPage *pPage1 = pBt->pPage1;
#ifndef SQLITE_OMIT_SHARED_CACHE
      assert( !pBt->pWriter );
      pBt->pWriter = p;
      pBt->isExclusive = (u8)(wrflag>1);

#endif

      /* If the db-size header field is incorrect (as it may be if an old
      ** client has been writing the database file), update it now. Doing
      ** this sooner rather than later means the database size can safely 
      ** re-read the database size from page 1 if a savepoint or transaction
      ** rollback occurs within the transaction.
................................................................................
** using the sqlite3BtreeSavepoint() function.
*/
int sqlite3BtreeBeginStmt(Btree *p, int iStatement){
  int rc;
  BtShared *pBt = p->pBt;
  sqlite3BtreeEnter(p);
  assert( p->inTrans==TRANS_WRITE );
  assert( pBt->readOnly==0 );
  assert( iStatement>0 );
  assert( iStatement>p->db->nSavepoint );
  assert( pBt->inTransaction==TRANS_WRITE );
  /* At the pager level, a statement transaction is a savepoint with
  ** an index greater than all savepoints created explicitly using
  ** SQL statements. It is illegal to open, release or rollback any
  ** such savepoints while the statement transaction savepoint is active.
................................................................................
  if( p && p->inTrans==TRANS_WRITE ){
    BtShared *pBt = p->pBt;
    assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
    assert( iSavepoint>=0 || (iSavepoint==-1 && op==SAVEPOINT_ROLLBACK) );
    sqlite3BtreeEnter(p);
    rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
    if( rc==SQLITE_OK ){

      if( iSavepoint<0 && pBt->initiallyEmpty ) pBt->nPage = 0;

      rc = newDatabase(pBt);
      pBt->nPage = get4byte(28 + pBt->pPage1->aData);

      /* The database size was written into the offset 28 of the header
      ** when the transaction started, so we know that the value at offset
      ** 28 is nonzero. */
      assert( pBt->nPage>0 );
................................................................................
  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->readOnly) ){
    return SQLITE_READONLY;
  }
  if( iTable==1 && btreePagecount(pBt)==0 ){
    assert( wrFlag==0 );
    iTable = 0;
  }

................................................................................
  pCur->validNKey = 0;
  if( pNewPage->nCell<1 || pNewPage->intKey!=pCur->apPage[i]->intKey ){
    return SQLITE_CORRUPT_BKPT;
  }
  return SQLITE_OK;
}

#ifndef NDEBUG
/*
** 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
** cells in pParent, that page number iChild is the right-child of
** the page.
*/
................................................................................
** the largest cell index.
*/
static void moveToParent(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->iPage>0 );
  assert( pCur->apPage[pCur->iPage] );







  assertParentIndex(
    pCur->apPage[pCur->iPage-1], 
    pCur->aiIdx[pCur->iPage-1], 
    pCur->apPage[pCur->iPage]->pgno
  );



  releasePage(pCur->apPage[pCur->iPage]);
  pCur->iPage--;
  pCur->info.nSize = 0;
  pCur->validNKey = 0;
}

/*
................................................................................
        ** 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 
        ** 2 bytes of the cell.
        */
        int nCell = pCell[0];
        if( !(nCell & 0x80)
         && nCell<=pPage->maxLocal
         && (pCell+nCell+1)<=pPage->aDataEnd
        ){
          /* This branch runs if the record-size field of the cell is a
          ** single byte varint and the record fits entirely on the main
          ** b-tree page.  */
          testcase( pCell+nCell+1==pPage->aDataEnd );
          c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
        }else if( !(pCell[1] & 0x80) 
          && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
          && (pCell+nCell+2)<=pPage->aDataEnd
        ){
          /* The record-size field is a 2 byte varint and the record 
          ** fits entirely on the main b-tree page.  */
          testcase( pCell+nCell+2==pPage->aDataEnd );
          c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
        }else{
          /* The record flows over onto one or more overflow pages. In
................................................................................
    return SQLITE_OK;
  }
  pCur->skipNext = 0;

  pPage = pCur->apPage[pCur->iPage];
  idx = ++pCur->aiIdx[pCur->iPage];
  assert( pPage->isInit );






  assert( idx<=pPage->nCell );

  pCur->info.nSize = 0;
  pCur->validNKey = 0;
  if( idx>=pPage->nCell ){
    if( !pPage->leaf ){
      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
      if( rc ) return rc;
................................................................................

  /* Increment the free page count on pPage1 */
  rc = sqlite3PagerWrite(pPage1->pDbPage);
  if( rc ) goto freepage_out;
  nFree = get4byte(&pPage1->aData[36]);
  put4byte(&pPage1->aData[36], nFree+1);

  if( pBt->secureDelete ){
    /* If the secure_delete option is enabled, then
    ** always fully overwrite deleted information with zeros.
    */
    if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0) )
     ||            ((rc = sqlite3PagerWrite(pPage->pDbPage))!=0)
    ){
      goto freepage_out;
................................................................................
      ** to 3.6.0 or later) we should consider fixing the conditional above
      ** to read "usableSize/4-2" instead of "usableSize/4-8".
      */
      rc = sqlite3PagerWrite(pTrunk->pDbPage);
      if( rc==SQLITE_OK ){
        put4byte(&pTrunk->aData[4], nLeaf+1);
        put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
        if( pPage && !pBt->secureDelete ){
          sqlite3PagerDontWrite(pPage->pDbPage);
        }
        rc = btreeSetHasContent(pBt, iPage);
      }
      TRACE(("FREE-PAGE: %d leaf on trunk page %d\n",pPage->pgno,pTrunk->pgno));
      goto freepage_out;
    }
................................................................................
      ** later on.  
      **
      ** But not if we are in secure-delete mode. In secure-delete mode,
      ** the dropCell() routine will overwrite the entire cell with zeroes.
      ** In this case, temporarily copy the cell into the aOvflSpace[]
      ** buffer. It will be copied out again as soon as the aSpace[] buffer
      ** is allocated.  */
      if( pBt->secureDelete ){
        int iOff;

        iOff = SQLITE_PTR_TO_INT(apDiv[i]) - SQLITE_PTR_TO_INT(pParent->aData);
        if( (iOff+szNew[i])>(int)pBt->usableSize ){
          rc = SQLITE_CORRUPT_BKPT;
          memset(apOld, 0, (i+1)*sizeof(MemPage*));
          goto balance_cleanup;
................................................................................

  if( pCur->eState==CURSOR_FAULT ){
    assert( pCur->skipNext!=SQLITE_OK );
    return pCur->skipNext;
  }

  assert( cursorHoldsMutex(pCur) );
  assert( pCur->wrFlag && pBt->inTransaction==TRANS_WRITE && !pBt->readOnly );

  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );

  /* Assert that the caller has been consistent. If this cursor was opened
  ** expecting an index b-tree, then the caller should be inserting blob
  ** keys with no associated data. If the cursor was opened expecting an
  ** intkey table, the caller should be inserting integer keys with a
  ** blob of associated data.  */
................................................................................
  MemPage *pPage;                      /* Page to delete cell from */
  unsigned char *pCell;                /* Pointer to cell to delete */
  int iCellIdx;                        /* Index of cell to delete */
  int iCellDepth;                      /* Depth of node containing pCell */ 

  assert( cursorHoldsMutex(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( !pBt->readOnly );
  assert( pCur->wrFlag );
  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)
  ){
................................................................................
  MemPage *pRoot;
  Pgno pgnoRoot;
  int rc;
  int ptfFlags;          /* Page-type flage for the root page of new table */

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( !pBt->readOnly );

#ifdef SQLITE_OMIT_AUTOVACUUM
  rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
  if( rc ){
    return rc;
  }
#else
................................................................................
  assert( idx>=0 && idx<=15 );

  *pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);

  /* If auto-vacuum is disabled in this build and this is an auto-vacuum
  ** database, mark the database as read-only.  */
#ifdef SQLITE_OMIT_AUTOVACUUM
  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ) pBt->readOnly = 1;


#endif

  sqlite3BtreeLeave(p);
}

/*
** Write meta-information back into the database.  Meta[0] is
................................................................................
  **   (c) the connection holds a write-lock on the table (if required),
  **   (d) there are no conflicting read-locks, and
  **   (e) the cursor points at a valid row of an intKey table.
  */
  if( !pCsr->wrFlag ){
    return SQLITE_READONLY;
  }

  assert( !pCsr->pBt->readOnly && pCsr->pBt->inTransaction==TRANS_WRITE );
  assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
  assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );
  assert( pCsr->apPage[pCsr->iPage]->intKey );

  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 1);
}

................................................................................
  int rc;                         /* Return code */
 
  assert( iVersion==1 || iVersion==2 );

  /* If setting the version fields to 1, do not automatically open the
  ** WAL connection, even if the version fields are currently set to 2.
  */
  pBt->doNotUseWAL = (u8)(iVersion==1);


  rc = sqlite3BtreeBeginTrans(pBtree, 0);
  if( rc==SQLITE_OK ){
    u8 *aData = pBt->pPage1->aData;
    if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
      rc = sqlite3BtreeBeginTrans(pBtree, 2);
      if( rc==SQLITE_OK ){
................................................................................
          aData[18] = (u8)iVersion;
          aData[19] = (u8)iVersion;
        }
      }
    }
  }

  pBt->doNotUseWAL = 0;
  return rc;
}

  if( !p->sharable ){
    return SQLITE_OK;
  }

  /* If some other connection is holding an exclusive lock, the
  ** requested lock may not be obtained.
  */
  if( pBt->pWriter!=p && (pBt->btsFlags & BTS_EXCLUSIVE)!=0 ){
    sqlite3ConnectionBlocked(p->db, pBt->pWriter->db);
    return SQLITE_LOCKED_SHAREDCACHE;
  }

  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
    /* The condition (pIter->eLock!=eLock) in the following if(...) 
    ** statement is a simplification of:
................................................................................
    */
    assert( pIter->eLock==READ_LOCK || pIter->eLock==WRITE_LOCK );
    assert( eLock==READ_LOCK || pIter->pBtree==p || pIter->eLock==READ_LOCK);
    if( pIter->pBtree!=p && pIter->iTable==iTab && pIter->eLock!=eLock ){
      sqlite3ConnectionBlocked(p->db, pIter->pBtree->db);
      if( eLock==WRITE_LOCK ){
        assert( p==pBt->pWriter );
        pBt->btsFlags |= BTS_PENDING;
      }
      return SQLITE_LOCKED_SHAREDCACHE;
    }
  }
  return SQLITE_OK;
}
#endif /* !SQLITE_OMIT_SHARED_CACHE */
................................................................................

#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** Release all the table locks (locks obtained via calls to
** the setSharedCacheTableLock() procedure) held by Btree object p.
**
** This function assumes that Btree p has an open read or write 
** transaction. If it does not, then the BTS_PENDING flag
** may be incorrectly cleared.
*/
static void clearAllSharedCacheTableLocks(Btree *p){
  BtShared *pBt = p->pBt;
  BtLock **ppIter = &pBt->pLock;

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( p->sharable || 0==*ppIter );
  assert( p->inTrans>0 );

  while( *ppIter ){
    BtLock *pLock = *ppIter;
    assert( (pBt->btsFlags & BTS_EXCLUSIVE)==0 || pBt->pWriter==pLock->pBtree );
    assert( pLock->pBtree->inTrans>=pLock->eLock );
    if( pLock->pBtree==p ){
      *ppIter = pLock->pNext;
      assert( pLock->iTable!=1 || pLock==&p->lock );
      if( pLock->iTable!=1 ){
        sqlite3_free(pLock);
      }
    }else{
      ppIter = &pLock->pNext;
    }
  }

  assert( (pBt->btsFlags & BTS_PENDING)==0 || pBt->pWriter );
  if( pBt->pWriter==p ){
    pBt->pWriter = 0;
    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);

  }else if( pBt->nTransaction==2 ){
    /* This function is called when Btree p is concluding its 
    ** transaction. If there currently exists a writer, and p is not
    ** that writer, then the number of locks held by connections other
    ** than the writer must be about to drop to zero. In this case
    ** set the BTS_PENDING flag to 0.
    **
    ** If there is not currently a writer, then BTS_PENDING must
    ** be zero already. So this next line is harmless in that case.
    */
    pBt->btsFlags &= ~BTS_PENDING;
  }
}

/*
** This function changes all write-locks held by Btree p into read-locks.
*/
static void downgradeAllSharedCacheTableLocks(Btree *p){
  BtShared *pBt = p->pBt;
  if( pBt->pWriter==p ){
    BtLock *pLock;
    pBt->pWriter = 0;
    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);

    for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
      assert( pLock->eLock==READ_LOCK || pLock->pBtree==p );
      pLock->eLock = READ_LOCK;
    }
  }
}

................................................................................
  assert( pPage->pBt!=0 );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( start>=pPage->hdrOffset+6+pPage->childPtrSize );
  assert( (start + size) <= (int)pPage->pBt->usableSize );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( size>=0 );   /* Minimum cell size is 4 */

  if( pPage->pBt->btsFlags & BTS_SECURE_DELETE ){
    /* Overwrite deleted information with zeros when the secure_delete
    ** option is enabled */
    memset(&data[start], 0, size);
  }

  /* Add the space back into the linked list of freeblocks.  Note that
  ** even though the freeblock list was checked by btreeInitPage(),
................................................................................
    pPage->intKey = 0;
    pPage->hasData = 0;
    pPage->maxLocal = pBt->maxLocal;
    pPage->minLocal = pBt->minLocal;
  }else{
    return SQLITE_CORRUPT_BKPT;
  }
  pPage->max1bytePayload = pBt->max1bytePayload;
  return SQLITE_OK;
}

/*
** Initialize the auxiliary information for a disk block.
**
** Return SQLITE_OK on success.  If we see that the page does
................................................................................
  u16 first;

  assert( sqlite3PagerPagenumber(pPage->pDbPage)==pPage->pgno );
  assert( sqlite3PagerGetExtra(pPage->pDbPage) == (void*)pPage );
  assert( sqlite3PagerGetData(pPage->pDbPage) == data );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pBt->btsFlags & BTS_SECURE_DELETE ){
    memset(&data[hdr], 0, pBt->usableSize - hdr);
  }
  data[hdr] = (char)flags;
  first = hdr + 8 + 4*((flags&PTF_LEAF)==0 ?1:0);
  memset(&data[hdr+1], 0, 4);
  data[hdr+7] = 0;
  put2byte(&data[hdr+5], pBt->usableSize);
................................................................................
    pBt->openFlags = (u8)flags;
    pBt->db = db;
    sqlite3PagerSetBusyhandler(pBt->pPager, btreeInvokeBusyHandler, pBt);
    p->pBt = pBt;
  
    pBt->pCursor = 0;
    pBt->pPage1 = 0;
    if( sqlite3PagerIsreadonly(pBt->pPager) ) pBt->btsFlags |= BTS_READ_ONLY;
#ifdef SQLITE_SECURE_DELETE
    pBt->btsFlags |= BTS_SECURE_DELETE;
#endif
    pBt->pageSize = (zDbHeader[16]<<8) | (zDbHeader[17]<<16);
    if( pBt->pageSize<512 || pBt->pageSize>SQLITE_MAX_PAGE_SIZE
         || ((pBt->pageSize-1)&pBt->pageSize)!=0 ){
      pBt->pageSize = 0;
#ifndef SQLITE_OMIT_AUTOVACUUM
      /* If the magic name ":memory:" will create an in-memory database, then
................................................................................
        pBt->autoVacuum = (SQLITE_DEFAULT_AUTOVACUUM ? 1 : 0);
        pBt->incrVacuum = (SQLITE_DEFAULT_AUTOVACUUM==2 ? 1 : 0);
      }
#endif
      nReserve = 0;
    }else{
      nReserve = zDbHeader[20];
      pBt->btsFlags |= BTS_PAGESIZE_FIXED;
#ifndef SQLITE_OMIT_AUTOVACUUM
      pBt->autoVacuum = (get4byte(&zDbHeader[36 + 4*4])?1:0);
      pBt->incrVacuum = (get4byte(&zDbHeader[36 + 7*4])?1:0);
#endif
    }
    rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
    if( rc ) goto btree_open_out;
................................................................................
** of the database file used for locking (beginning at PENDING_BYTE,
** the first byte past the 1GB boundary, 0x40000000) needs to occur
** at the beginning of a page.
**
** If parameter nReserve is less than zero, then the number of reserved
** bytes per page is left unchanged.
**
** If the iFix!=0 then the BTS_PAGESIZE_FIXED flag is set so that the page size
** and autovacuum mode can no longer be changed.
*/
int sqlite3BtreeSetPageSize(Btree *p, int pageSize, int nReserve, int iFix){
  int rc = SQLITE_OK;
  BtShared *pBt = p->pBt;
  assert( nReserve>=-1 && nReserve<=255 );
  sqlite3BtreeEnter(p);
  if( pBt->btsFlags & BTS_PAGESIZE_FIXED ){
    sqlite3BtreeLeave(p);
    return SQLITE_READONLY;
  }
  if( nReserve<0 ){
    nReserve = pBt->pageSize - pBt->usableSize;
  }
  assert( nReserve>=0 && nReserve<=255 );
................................................................................
    assert( (pageSize & 7)==0 );
    assert( !pBt->pPage1 && !pBt->pCursor );
    pBt->pageSize = (u32)pageSize;
    freeTempSpace(pBt);
  }
  rc = sqlite3PagerSetPagesize(pBt->pPager, &pBt->pageSize, nReserve);
  pBt->usableSize = pBt->pageSize - (u16)nReserve;
  if( iFix ) pBt->btsFlags |= BTS_PAGESIZE_FIXED;
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** Return the currently defined page size
*/
................................................................................
  sqlite3BtreeEnter(p);
  n = sqlite3PagerMaxPageCount(p->pBt->pPager, mxPage);
  sqlite3BtreeLeave(p);
  return n;
}

/*
** Set the BTS_SECURE_DELETE flag if newFlag is 0 or 1.  If newFlag is -1,
** then make no changes.  Always return the value of the BTS_SECURE_DELETE
** setting after the change.
*/
int sqlite3BtreeSecureDelete(Btree *p, int newFlag){
  int b;
  if( p==0 ) return 0;
  sqlite3BtreeEnter(p);
  if( newFlag>=0 ){
    p->pBt->btsFlags &= ~BTS_SECURE_DELETE;
    if( newFlag ) p->pBt->btsFlags |= BTS_SECURE_DELETE;
  } 

  b = (p->pBt->btsFlags & BTS_SECURE_DELETE)!=0;
  sqlite3BtreeLeave(p);
  return b;
}
#endif /* !defined(SQLITE_OMIT_PAGER_PRAGMAS) || !defined(SQLITE_OMIT_VACUUM) */

/*
** Change the 'auto-vacuum' property of the database. If the 'autoVacuum'
................................................................................
  return SQLITE_READONLY;
#else
  BtShared *pBt = p->pBt;
  int rc = SQLITE_OK;
  u8 av = (u8)autoVacuum;

  sqlite3BtreeEnter(p);
  if( (pBt->btsFlags & BTS_PAGESIZE_FIXED)!=0 && (av ?1:0)!=pBt->autoVacuum ){
    rc = SQLITE_READONLY;
  }else{
    pBt->autoVacuum = av ?1:0;
    pBt->incrVacuum = av==2 ?1:0;
  }
  sqlite3BtreeLeave(p);
  return rc;
................................................................................
    rc = SQLITE_NOTADB;
    if( memcmp(page1, zMagicHeader, 16)!=0 ){
      goto page1_init_failed;
    }

#ifdef SQLITE_OMIT_WAL
    if( page1[18]>1 ){
      pBt->btsFlags |= BTS_READ_ONLY;
    }
    if( page1[19]>1 ){
      goto page1_init_failed;
    }
#else
    if( page1[18]>2 ){
      pBt->btsFlags |= BTS_READ_ONLY;
    }
    if( page1[19]>2 ){
      goto page1_init_failed;
    }

    /* If the write version is set to 2, this database should be accessed
    ** in WAL mode. If the log is not already open, open it now. Then 
    ** return SQLITE_OK and return without populating BtShared.pPage1.
    ** The caller detects this and calls this function again. This is
    ** required as the version of page 1 currently in the page1 buffer
    ** may not be the latest version - there may be a newer one in the log
    ** file.
    */
    if( page1[19]==2 && (pBt->btsFlags & BTS_NO_WAL)==0 ){
      int isOpen = 0;
      rc = sqlite3PagerOpenWal(pBt->pPager, &isOpen);
      if( rc!=SQLITE_OK ){
        goto page1_init_failed;
      }else if( isOpen==0 ){
#ifdef SQLITE_DEFAULT_WAL_SAFETYLEVEL
        /* Default to specified safety_level for WAL mode */
................................................................................
  ** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
  ** page pointer.
  */
  pBt->maxLocal = (u16)((pBt->usableSize-12)*64/255 - 23);
  pBt->minLocal = (u16)((pBt->usableSize-12)*32/255 - 23);
  pBt->maxLeaf = (u16)(pBt->usableSize - 35);
  pBt->minLeaf = (u16)((pBt->usableSize-12)*32/255 - 23);
  if( pBt->maxLocal>127 ){
    pBt->max1bytePayload = 127;
  }else{
    pBt->max1bytePayload = (u8)pBt->maxLocal;
  }
  assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
  pBt->pPage1 = pPage1;
  pBt->nPage = nPage;
  return SQLITE_OK;

page1_init_failed:
  releasePage(pPage1);
................................................................................
  assert( pBt->usableSize<=pBt->pageSize && pBt->usableSize+255>=pBt->pageSize);
  data[20] = (u8)(pBt->pageSize - pBt->usableSize);
  data[21] = 64;
  data[22] = 32;
  data[23] = 32;
  memset(&data[24], 0, 100-24);
  zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
  pBt->btsFlags |= BTS_PAGESIZE_FIXED;
#ifndef SQLITE_OMIT_AUTOVACUUM
  assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
  assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
  put4byte(&data[36 + 4*4], pBt->autoVacuum);
  put4byte(&data[36 + 7*4], pBt->incrVacuum);
#endif
  pBt->nPage = 1;
................................................................................
  ** is requested, this is a no-op.
  */
  if( p->inTrans==TRANS_WRITE || (p->inTrans==TRANS_READ && !wrflag) ){
    goto trans_begun;
  }

  /* Write transactions are not possible on a read-only database */
  if( (pBt->btsFlags & BTS_READ_ONLY)!=0 && wrflag ){
    rc = SQLITE_READONLY;
    goto trans_begun;
  }

#ifndef SQLITE_OMIT_SHARED_CACHE
  /* If another database handle has already opened a write transaction 
  ** on this shared-btree structure and a second write transaction is
  ** requested, return SQLITE_LOCKED.
  */
  if( (wrflag && pBt->inTransaction==TRANS_WRITE)
   || (pBt->btsFlags & BTS_PENDING)!=0
  ){
    pBlock = pBt->pWriter->db;
  }else if( wrflag>1 ){
    BtLock *pIter;
    for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
      if( pIter->pBtree!=p ){
        pBlock = pIter->pBtree->db;
        break;
................................................................................

  /* Any read-only or read-write transaction implies a read-lock on 
  ** page 1. So if some other shared-cache client already has a write-lock 
  ** on page 1, the transaction cannot be opened. */
  rc = querySharedCacheTableLock(p, MASTER_ROOT, READ_LOCK);
  if( SQLITE_OK!=rc ) goto trans_begun;

  pBt->btsFlags &= ~BTS_INITIALLY_EMPTY;
  if( pBt->nPage==0 ) pBt->btsFlags |= BTS_INITIALLY_EMPTY;
  do {
    /* Call lockBtree() until either pBt->pPage1 is populated or
    ** lockBtree() returns something other than SQLITE_OK. lockBtree()
    ** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
    ** reading page 1 it discovers that the page-size of the database 
    ** file is not pBt->pageSize. In this case lockBtree() will update
    ** pBt->pageSize to the page-size of the file on disk.
    */
    while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );

    if( rc==SQLITE_OK && wrflag ){
      if( (pBt->btsFlags & BTS_READ_ONLY)!=0 ){
        rc = SQLITE_READONLY;
      }else{
        rc = sqlite3PagerBegin(pBt->pPager,wrflag>1,sqlite3TempInMemory(p->db));
        if( rc==SQLITE_OK ){
          rc = newDatabase(pBt);
        }
      }
................................................................................
      pBt->inTransaction = p->inTrans;
    }
    if( wrflag ){
      MemPage *pPage1 = pBt->pPage1;
#ifndef SQLITE_OMIT_SHARED_CACHE
      assert( !pBt->pWriter );
      pBt->pWriter = p;
      pBt->btsFlags &= ~BTS_EXCLUSIVE;
      if( wrflag>1 ) pBt->btsFlags |= BTS_EXCLUSIVE;
#endif

      /* If the db-size header field is incorrect (as it may be if an old
      ** client has been writing the database file), update it now. Doing
      ** this sooner rather than later means the database size can safely 
      ** re-read the database size from page 1 if a savepoint or transaction
      ** rollback occurs within the transaction.
................................................................................
** using the sqlite3BtreeSavepoint() function.
*/
int sqlite3BtreeBeginStmt(Btree *p, int iStatement){
  int rc;
  BtShared *pBt = p->pBt;
  sqlite3BtreeEnter(p);
  assert( p->inTrans==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( iStatement>0 );
  assert( iStatement>p->db->nSavepoint );
  assert( pBt->inTransaction==TRANS_WRITE );
  /* At the pager level, a statement transaction is a savepoint with
  ** an index greater than all savepoints created explicitly using
  ** SQL statements. It is illegal to open, release or rollback any
  ** such savepoints while the statement transaction savepoint is active.
................................................................................
  if( p && p->inTrans==TRANS_WRITE ){
    BtShared *pBt = p->pBt;
    assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
    assert( iSavepoint>=0 || (iSavepoint==-1 && op==SAVEPOINT_ROLLBACK) );
    sqlite3BtreeEnter(p);
    rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
    if( rc==SQLITE_OK ){
      if( iSavepoint<0 && (pBt->btsFlags & BTS_INITIALLY_EMPTY)!=0 ){
        pBt->nPage = 0;
      }
      rc = newDatabase(pBt);
      pBt->nPage = get4byte(28 + pBt->pPage1->aData);

      /* The database size was written into the offset 28 of the header
      ** when the transaction started, so we know that the value at offset
      ** 28 is nonzero. */
      assert( pBt->nPage>0 );
................................................................................
  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( iTable==1 && btreePagecount(pBt)==0 ){
    assert( wrFlag==0 );
    iTable = 0;
  }

................................................................................
  pCur->validNKey = 0;
  if( pNewPage->nCell<1 || pNewPage->intKey!=pCur->apPage[i]->intKey ){
    return SQLITE_CORRUPT_BKPT;
  }
  return SQLITE_OK;
}

#if 0
/*
** 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
** cells in pParent, that page number iChild is the right-child of
** the page.
*/
................................................................................
** the largest cell index.
*/
static void moveToParent(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->iPage>0 );
  assert( pCur->apPage[pCur->iPage] );

  /* UPDATE: It is actually possible for the condition tested by the assert
  ** below to be untrue if the database file is corrupt. This can occur if
  ** one cursor has modified page pParent while a reference to it is held 
  ** by a second cursor. Which can only happen if a single page is linked
  ** into more than one b-tree structure in a corrupt database.  */
#if 0
  assertParentIndex(
    pCur->apPage[pCur->iPage-1], 
    pCur->aiIdx[pCur->iPage-1], 
    pCur->apPage[pCur->iPage]->pgno
  );
#endif
  testcase( pCur->aiIdx[pCur->iPage-1] > pCur->apPage[pCur->iPage-1]->nCell );

  releasePage(pCur->apPage[pCur->iPage]);
  pCur->iPage--;
  pCur->info.nSize = 0;
  pCur->validNKey = 0;
}

/*
................................................................................
        ** 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 
        ** 2 bytes of the cell.
        */
        int nCell = pCell[0];

        if( nCell<=pPage->max1bytePayload
         /* && (pCell+nCell)<pPage->aDataEnd */
        ){
          /* This branch runs if the record-size field of the cell is a
          ** single byte varint and the record fits entirely on the main
          ** b-tree page.  */
          testcase( pCell+nCell+1==pPage->aDataEnd );
          c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
        }else if( !(pCell[1] & 0x80) 
          && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
          /* && (pCell+nCell+2)<=pPage->aDataEnd */
        ){
          /* The record-size field is a 2 byte varint and the record 
          ** fits entirely on the main b-tree page.  */
          testcase( pCell+nCell+2==pPage->aDataEnd );
          c = sqlite3VdbeRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
        }else{
          /* The record flows over onto one or more overflow pages. In
................................................................................
    return SQLITE_OK;
  }
  pCur->skipNext = 0;

  pPage = pCur->apPage[pCur->iPage];
  idx = ++pCur->aiIdx[pCur->iPage];
  assert( pPage->isInit );

  /* If the database file is corrupt, it is possible for the value of idx 
  ** to be invalid here. This can only occur if a second cursor modifies
  ** the page while cursor pCur is holding a reference to it. Which can
  ** only happen if the database is corrupt in such a way as to link the
  ** page into more than one b-tree structure. */
  testcase( idx>pPage->nCell );

  pCur->info.nSize = 0;
  pCur->validNKey = 0;
  if( idx>=pPage->nCell ){
    if( !pPage->leaf ){
      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
      if( rc ) return rc;
................................................................................

  /* Increment the free page count on pPage1 */
  rc = sqlite3PagerWrite(pPage1->pDbPage);
  if( rc ) goto freepage_out;
  nFree = get4byte(&pPage1->aData[36]);
  put4byte(&pPage1->aData[36], nFree+1);

  if( pBt->btsFlags & BTS_SECURE_DELETE ){
    /* If the secure_delete option is enabled, then
    ** always fully overwrite deleted information with zeros.
    */
    if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0) )
     ||            ((rc = sqlite3PagerWrite(pPage->pDbPage))!=0)
    ){
      goto freepage_out;
................................................................................
      ** to 3.6.0 or later) we should consider fixing the conditional above
      ** to read "usableSize/4-2" instead of "usableSize/4-8".
      */
      rc = sqlite3PagerWrite(pTrunk->pDbPage);
      if( rc==SQLITE_OK ){
        put4byte(&pTrunk->aData[4], nLeaf+1);
        put4byte(&pTrunk->aData[8+nLeaf*4], iPage);
        if( pPage && (pBt->btsFlags & BTS_SECURE_DELETE)==0 ){
          sqlite3PagerDontWrite(pPage->pDbPage);
        }
        rc = btreeSetHasContent(pBt, iPage);
      }
      TRACE(("FREE-PAGE: %d leaf on trunk page %d\n",pPage->pgno,pTrunk->pgno));
      goto freepage_out;
    }
................................................................................
      ** later on.  
      **
      ** But not if we are in secure-delete mode. In secure-delete mode,
      ** the dropCell() routine will overwrite the entire cell with zeroes.
      ** In this case, temporarily copy the cell into the aOvflSpace[]
      ** buffer. It will be copied out again as soon as the aSpace[] buffer
      ** is allocated.  */
      if( pBt->btsFlags & BTS_SECURE_DELETE ){
        int iOff;

        iOff = SQLITE_PTR_TO_INT(apDiv[i]) - SQLITE_PTR_TO_INT(pParent->aData);
        if( (iOff+szNew[i])>(int)pBt->usableSize ){
          rc = SQLITE_CORRUPT_BKPT;
          memset(apOld, 0, (i+1)*sizeof(MemPage*));
          goto balance_cleanup;
................................................................................

  if( pCur->eState==CURSOR_FAULT ){
    assert( pCur->skipNext!=SQLITE_OK );
    return pCur->skipNext;
  }

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

  /* Assert that the caller has been consistent. If this cursor was opened
  ** expecting an index b-tree, then the caller should be inserting blob
  ** keys with no associated data. If the cursor was opened expecting an
  ** intkey table, the caller should be inserting integer keys with a
  ** blob of associated data.  */
................................................................................
  MemPage *pPage;                      /* Page to delete cell from */
  unsigned char *pCell;                /* Pointer to cell to delete */
  int iCellIdx;                        /* Index of cell to delete */
  int iCellDepth;                      /* Depth of node containing pCell */ 

  assert( cursorHoldsMutex(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( pCur->wrFlag );
  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)
  ){
................................................................................
  MemPage *pRoot;
  Pgno pgnoRoot;
  int rc;
  int ptfFlags;          /* Page-type flage for the root page of new table */

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );

#ifdef SQLITE_OMIT_AUTOVACUUM
  rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
  if( rc ){
    return rc;
  }
#else
................................................................................
  assert( idx>=0 && idx<=15 );

  *pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);

  /* If auto-vacuum is disabled in this build and this is an auto-vacuum
  ** database, mark the database as read-only.  */
#ifdef SQLITE_OMIT_AUTOVACUUM
  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ){
    pBt->btsFlags |= BTS_READ_ONLY;
  }
#endif

  sqlite3BtreeLeave(p);
}

/*
** Write meta-information back into the database.  Meta[0] is
................................................................................
  **   (c) the connection holds a write-lock on the table (if required),
  **   (d) there are no conflicting read-locks, and
  **   (e) the cursor points at a valid row of an intKey table.
  */
  if( !pCsr->wrFlag ){
    return SQLITE_READONLY;
  }
  assert( (pCsr->pBt->btsFlags & BTS_READ_ONLY)==0
              && pCsr->pBt->inTransaction==TRANS_WRITE );
  assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
  assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );
  assert( pCsr->apPage[pCsr->iPage]->intKey );

  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 1);
}

................................................................................
  int rc;                         /* Return code */
 
  assert( iVersion==1 || iVersion==2 );

  /* If setting the version fields to 1, do not automatically open the
  ** WAL connection, even if the version fields are currently set to 2.
  */
  pBt->btsFlags &= ~BTS_NO_WAL;
  if( iVersion==1 ) pBt->btsFlags |= BTS_NO_WAL;

  rc = sqlite3BtreeBeginTrans(pBtree, 0);
  if( rc==SQLITE_OK ){
    u8 *aData = pBt->pPage1->aData;
    if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
      rc = sqlite3BtreeBeginTrans(pBtree, 2);
      if( rc==SQLITE_OK ){
................................................................................
          aData[18] = (u8)iVersion;
          aData[19] = (u8)iVersion;
        }
      }
    }
  }

  pBt->btsFlags &= ~BTS_NO_WAL;
  return rc;
}

  u8 isInit;           /* True if previously initialized. MUST BE FIRST! */
  u8 nOverflow;        /* Number of overflow cell bodies in aCell[] */
  u8 intKey;           /* True if intkey flag is set */
  u8 leaf;             /* True if leaf flag is set */
  u8 hasData;          /* True if this page stores data */
  u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
  u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */

  u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
  u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
  u16 cellOffset;      /* Index in aData of first cell pointer */
  u16 nFree;           /* Number of free bytes on the page */
  u16 nCell;           /* Number of cells on this page, local and ovfl */
  u16 maskPage;        /* Mask for page offset */
  struct _OvflCell {   /* Cells that will not fit on aData[] */
................................................................................
**   This feature is included to help prevent writer-starvation.
*/
struct BtShared {
  Pager *pPager;        /* The page cache */
  sqlite3 *db;          /* Database connection currently using this Btree */
  BtCursor *pCursor;    /* A list of all open cursors */
  MemPage *pPage1;      /* First page of the database */
  u8 readOnly;          /* True if the underlying file is readonly */
  u8 pageSizeFixed;     /* True if the page size can no longer be changed */
  u8 secureDelete;      /* True if secure_delete is enabled */
  u8 initiallyEmpty;    /* Database is empty at start of transaction */
  u8 openFlags;         /* Flags to sqlite3BtreeOpen() */
#ifndef SQLITE_OMIT_AUTOVACUUM
  u8 autoVacuum;        /* True if auto-vacuum is enabled */
  u8 incrVacuum;        /* True if incr-vacuum is enabled */
#endif
  u8 inTransaction;     /* Transaction state */
  u8 doNotUseWAL;       /* If true, do not open write-ahead-log file */

  u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
  u16 minLocal;         /* Minimum local payload in non-LEAFDATA tables */
  u16 maxLeaf;          /* Maximum local payload in a LEAFDATA table */
  u16 minLeaf;          /* Minimum local payload in a LEAFDATA table */
  u32 pageSize;         /* Total number of bytes on a page */
  u32 usableSize;       /* Number of usable bytes on each page */
  int nTransaction;     /* Number of open transactions (read + write) */
................................................................................
  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this object */
  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
  BtLock *pLock;        /* List of locks held on this shared-btree struct */
  Btree *pWriter;       /* Btree with currently open write transaction */
  u8 isExclusive;       /* True if pWriter has an EXCLUSIVE lock on the db */
  u8 isPending;         /* If waiting for read-locks to clear */
#endif
  u8 *pTmpSpace;        /* BtShared.pageSize bytes of space for tmp use */
};












/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
*/
typedef struct CellInfo CellInfo;
struct CellInfo {

  u8 isInit;           /* True if previously initialized. MUST BE FIRST! */
  u8 nOverflow;        /* Number of overflow cell bodies in aCell[] */
  u8 intKey;           /* True if intkey flag is set */
  u8 leaf;             /* True if leaf flag is set */
  u8 hasData;          /* True if this page stores data */
  u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
  u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
  u8 max1bytePayload;  /* min(maxLocal,127) */
  u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
  u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
  u16 cellOffset;      /* Index in aData of first cell pointer */
  u16 nFree;           /* Number of free bytes on the page */
  u16 nCell;           /* Number of cells on this page, local and ovfl */
  u16 maskPage;        /* Mask for page offset */
  struct _OvflCell {   /* Cells that will not fit on aData[] */
................................................................................
**   This feature is included to help prevent writer-starvation.
*/
struct BtShared {
  Pager *pPager;        /* The page cache */
  sqlite3 *db;          /* Database connection currently using this Btree */
  BtCursor *pCursor;    /* A list of all open cursors */
  MemPage *pPage1;      /* First page of the database */




  u8 openFlags;         /* Flags to sqlite3BtreeOpen() */
#ifndef SQLITE_OMIT_AUTOVACUUM
  u8 autoVacuum;        /* True if auto-vacuum is enabled */
  u8 incrVacuum;        /* True if incr-vacuum is enabled */
#endif
  u8 inTransaction;     /* Transaction state */
  u8 max1bytePayload;   /* Maximum first byte of cell for a 1-byte payload */
  u16 btsFlags;         /* Boolean parameters.  See BTS_* macros below */
  u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
  u16 minLocal;         /* Minimum local payload in non-LEAFDATA tables */
  u16 maxLeaf;          /* Maximum local payload in a LEAFDATA table */
  u16 minLeaf;          /* Minimum local payload in a LEAFDATA table */
  u32 pageSize;         /* Total number of bytes on a page */
  u32 usableSize;       /* Number of usable bytes on each page */
  int nTransaction;     /* Number of open transactions (read + write) */
................................................................................
  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this object */
  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
  BtLock *pLock;        /* List of locks held on this shared-btree struct */
  Btree *pWriter;       /* Btree with currently open write transaction */


#endif
  u8 *pTmpSpace;        /* BtShared.pageSize bytes of space for tmp use */
};

/*
** Allowed values for BtShared.btsFlags
*/
#define BTS_READ_ONLY        0x0001   /* Underlying file is readonly */
#define BTS_PAGESIZE_FIXED   0x0002   /* Page size can no longer be changed */
#define BTS_SECURE_DELETE    0x0004   /* PRAGMA secure_delete is enabled */
#define BTS_INITIALLY_EMPTY  0x0008   /* Database was empty at trans start */
#define BTS_NO_WAL           0x0010   /* Do not open write-ahead-log files */
#define BTS_EXCLUSIVE        0x0020   /* pWriter has an exclusive lock */
#define BTS_PENDING          0x0040   /* Waiting for read-locks to clear */

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
*/
typedef struct CellInfo CellInfo;
struct CellInfo {

  /* 
  ** Allocate the index structure. 
  */
  nName = sqlite3Strlen30(zName);
  nCol = pList->nExpr;
  pIndex = sqlite3DbMallocZero(db, 
      sizeof(Index) +                      /* Index structure  */
      ROUND8(sizeof(tRowcnt)*(nCol+1)) +   /* Index.aiRowEst   */
      sizeof(char *)*nCol +                /* Index.azColl     */
      sizeof(int)*nCol +                   /* Index.aiColumn   */
      sizeof(u8)*nCol +                    /* Index.aSortOrder */
      nName + 1 +                          /* Index.zName      */
      nExtra                               /* Collation sequence names */
  );
  if( db->mallocFailed ){
    goto exit_create_index;
  }

  pIndex->aiRowEst = (tRowcnt*)(&pIndex[1]);
  pIndex->azColl = (char**)
     ((char*)pIndex->aiRowEst + ROUND8(sizeof(tRowcnt)*nCol+1));
  assert( EIGHT_BYTE_ALIGNMENT(pIndex->aiRowEst) );
  assert( EIGHT_BYTE_ALIGNMENT(pIndex->azColl) );
  pIndex->aiColumn = (int *)(&pIndex->azColl[nCol]);
  pIndex->aSortOrder = (u8 *)(&pIndex->aiColumn[nCol]);
  pIndex->zName = (char *)(&pIndex->aSortOrder[nCol]);

  /* 
  ** Allocate the index structure. 
  */
  nName = sqlite3Strlen30(zName);
  nCol = pList->nExpr;
  pIndex = sqlite3DbMallocZero(db, 
      ROUND8(sizeof(Index)) +              /* Index structure  */
      ROUND8(sizeof(tRowcnt)*(nCol+1)) +   /* Index.aiRowEst   */
      sizeof(char *)*nCol +                /* Index.azColl     */
      sizeof(int)*nCol +                   /* Index.aiColumn   */
      sizeof(u8)*nCol +                    /* Index.aSortOrder */
      nName + 1 +                          /* Index.zName      */
      nExtra                               /* Collation sequence names */
  );
  if( db->mallocFailed ){
    goto exit_create_index;
  }
  zExtra = (char*)pIndex;
  pIndex->aiRowEst = (tRowcnt*)&zExtra[ROUND8(sizeof(Index))];
  pIndex->azColl = (char**)
     ((char*)pIndex->aiRowEst + ROUND8(sizeof(tRowcnt)*nCol+1));
  assert( EIGHT_BYTE_ALIGNMENT(pIndex->aiRowEst) );
  assert( EIGHT_BYTE_ALIGNMENT(pIndex->azColl) );
  pIndex->aiColumn = (int *)(&pIndex->azColl[nCol]);
  pIndex->aSortOrder = (u8 *)(&pIndex->aiColumn[nCol]);
  pIndex->zName = (char *)(&pIndex->aSortOrder[nCol]);

**                                return code of SQLITE_CONSTRAINT.
**
**  any              ABORT        Back out changes from the current command
**                                only (do not do a complete rollback) then
**                                cause sqlite3_exec() to return immediately
**                                with SQLITE_CONSTRAINT.
**
**  any              FAIL         Sqlite_exec() returns immediately with a
**                                return code of SQLITE_CONSTRAINT.  The
**                                transaction is not rolled back and any
**                                prior changes are retained.
**
**  any              IGNORE       The record number and data is popped from
**                                the stack and there is an immediate jump
**                                to label ignoreDest.

**                                return code of SQLITE_CONSTRAINT.
**
**  any              ABORT        Back out changes from the current command
**                                only (do not do a complete rollback) then
**                                cause sqlite3_exec() to return immediately
**                                with SQLITE_CONSTRAINT.
**
**  any              FAIL         Sqlite3_exec() returns immediately with a
**                                return code of SQLITE_CONSTRAINT.  The
**                                transaction is not rolled back and any
**                                prior changes are retained.
**
**  any              IGNORE       The record number and data is popped from
**                                the stack and there is an immediate jump
**                                to label ignoreDest.

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

#endif /* SQLITE_MUTEX_OMIT */

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

#endif /* !defined(SQLITE_MUTEX_OMIT) */

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

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

    0
#endif
  };

  return &sMutex;
}

#endif /* SQLITE_MUTEX_PTHREAD */

    0
#endif
  };

  return &sMutex;
}

#endif /* SQLITE_MUTEX_PTHREADS */

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









int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
  DO_OS_MALLOC_TEST(id);
  return id->pMethods->xFileControl(id, op, pArg);
}




int sqlite3OsSectorSize(sqlite3_file *id){
  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
}
int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
  return id->pMethods->xDeviceCharacteristics(id);
}
................................................................................
#endif
  rc = pVfs->xOpen(pVfs, zPath, pFile, openFlags, pFlagsOut);
  assert( rc==SQLITE_OK || pFile->pMethods==0 );
  return rc;
}
int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  DO_OS_MALLOC_TEST(0);

  return pVfs->xDelete(pVfs, zPath, dirSync);
}
int sqlite3OsAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut

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

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

int sqlite3OsSectorSize(sqlite3_file *id){
  int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
  return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
}
int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
  return id->pMethods->xDeviceCharacteristics(id);
}
................................................................................
#endif
  rc = pVfs->xOpen(pVfs, zPath, pFile, openFlags, pFlagsOut);
  assert( rc==SQLITE_OK || pFile->pMethods==0 );
  return rc;
}
int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
  DO_OS_MALLOC_TEST(0);
  assert( dirSync==0 || dirSync==1 );
  return pVfs->xDelete(pVfs, zPath, dirSync);
}
int sqlite3OsAccess(
  sqlite3_vfs *pVfs, 
  const char *zPath, 
  int flags, 
  int *pResOut

int sqlite3OsTruncate(sqlite3_file*, i64 size);
int sqlite3OsSync(sqlite3_file*, int);
int sqlite3OsFileSize(sqlite3_file*, i64 *pSize);
int sqlite3OsLock(sqlite3_file*, int);
int sqlite3OsUnlock(sqlite3_file*, int);
int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut);
int sqlite3OsFileControl(sqlite3_file*,int,void*);

#define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0
int sqlite3OsSectorSize(sqlite3_file *id);
int sqlite3OsDeviceCharacteristics(sqlite3_file *id);
int sqlite3OsShmMap(sqlite3_file *,int,int,int,void volatile **);
int sqlite3OsShmLock(sqlite3_file *id, int, int, int);
void sqlite3OsShmBarrier(sqlite3_file *id);
int sqlite3OsShmUnmap(sqlite3_file *id, int);


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

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


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

#if SQLITE_ENABLE_DATA_PROTECTION
  int protFlags;                      /* Data protection flags from unixOpen */
#endif
#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
  unsigned fsFlags;                   /* cached details from statfs() */
#endif
#if OS_VXWORKS
  int isDelete;                       /* Delete on close if true */
  struct vxworksFileId *pId;          /* Unique file ID */
#endif
#ifndef NDEBUG
  /* The next group of variables are used to track whether or not the
  ** transaction counter in bytes 24-27 of database files are updated
  ** whenever any part of the database changes.  An assertion fault will
  ** occur if a file is updated without also updating the transaction
................................................................................
#define UNIXFILE_PERSIST_WAL 0x04     /* Persistent WAL mode */
#ifndef SQLITE_DISABLE_DIRSYNC
# define UNIXFILE_DIRSYNC    0x08     /* Directory sync needed */
#else
# define UNIXFILE_DIRSYNC    0x00
#endif
#define UNIXFILE_PSOW        0x10     /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */




/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"

/*
................................................................................
  if( pFile->h>=0 ){
    robust_close(pFile, pFile->h, __LINE__);
    pFile->h = -1;
  }
#endif
#if OS_VXWORKS
  if( pFile->pId ){
    if( pFile->isDelete ){
      osUnlink(pFile->pId->zCanonicalName);
    }
    vxworksReleaseFileId(pFile->pId);
    pFile->pId = 0;
  }
#endif
  OSTRACE(("CLOSE   %-3d\n", pFile->h));
................................................................................
    */
    case SQLITE_FCNTL_DB_UNCHANGED: {
      ((unixFile*)id)->dbUpdate = 0;
      return SQLITE_OK;
    }
#endif
#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
    case SQLITE_FCNTL_SET_LOCKPROXYFILE:
    case SQLITE_FCNTL_GET_LOCKPROXYFILE: {
      return proxyFileControl(id,op,pArg);
    }
#endif /* SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) */
#if (SQLITE_ENABLE_APPLE_SPI>0) && defined(__APPLE__)
    case SQLITE_FCNTL_TRUNCATE_DATABASE: {
      return unixTruncateDatabase(pFile, (pArg ? (*(int *)pArg) : 0));
    }
................................................................................
      }
      pLockstate = (LockstatePID *)pArg;
      rc = unixLockstatePid(pFile, pLockstate->pid, &(pLockstate->state));
      return rc;
    }
      
#endif /* (SQLITE_ENABLE_APPLE_SPI>0) && defined(__APPLE__) */
    case SQLITE_FCNTL_SYNC_OMITTED: {
      return SQLITE_OK;  /* A no-op */
    }
  }
  return SQLITE_NOTFOUND;
}

/*
** Return the sector size in bytes of the underlying block device for
** the specified file. This is almost always 512 bytes, but may be
................................................................................
    nShmFilename = 6 + (int)strlen(zBasePath);
#endif
    pShmNode = sqlite3_malloc( sizeof(*pShmNode) + nShmFilename );
    if( pShmNode==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    memset(pShmNode, 0, sizeof(*pShmNode));
    zShmFilename = pShmNode->zFilename = (char*)&pShmNode[1];
#ifdef SQLITE_SHM_DIRECTORY
    sqlite3_snprintf(nShmFilename, zShmFilename, 
                     SQLITE_SHM_DIRECTORY "/sqlite-shm-%x-%x",
                     (u32)sStat.st_ino, (u32)sStat.st_dev);
#else
    sqlite3_snprintf(nShmFilename, zShmFilename, "%s-shm", zBasePath);
................................................................................

/*
** Initialize the contents of the unixFile structure pointed to by pId.
*/
static int fillInUnixFile(
  sqlite3_vfs *pVfs,      /* Pointer to vfs object */
  int h,                  /* Open file descriptor of file being opened */
  int syncDir,            /* True to sync directory on first sync */
  sqlite3_file *pId,      /* Write to the unixFile structure here */
  const char *zFilename,  /* Name of the file being opened */
  int noLock,             /* Omit locking if true */
  int isDelete,           /* Delete on close if true */
  int isReadOnly          /* True if the file is opened read-only */

){
  const sqlite3_io_methods *pLockingStyle;
  unixFile *pNew = (unixFile *)pId;
  int rc = SQLITE_OK;

  assert( pNew->pInode==NULL );

  /* Parameter isDelete is only used on vxworks. Express this explicitly 
  ** here to prevent compiler warnings about unused parameters.
  */
  UNUSED_PARAMETER(isDelete);

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

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

  OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
  pNew->h = h;
  pNew->pVfs = pVfs;
  pNew->zPath = zFilename;
  pNew->ctrlFlags = 0;

  if( sqlite3_uri_boolean(zFilename, "psow", SQLITE_POWERSAFE_OVERWRITE) ){
    pNew->ctrlFlags |= UNIXFILE_PSOW;
  }
  if( memcmp(pVfs->zName,"unix-excl",10)==0 ){
    pNew->ctrlFlags |= UNIXFILE_EXCL;
  }
  if( isReadOnly ){
    pNew->ctrlFlags |= UNIXFILE_RDONLY;
  }
  if( syncDir ){
    pNew->ctrlFlags |= UNIXFILE_DIRSYNC;
  }

#if OS_VXWORKS
  pNew->pId = vxworksFindFileId(zFilename);
  if( pNew->pId==0 ){
    noLock = 1;
    rc = SQLITE_NOMEM;
  }
#endif

  if( noLock ){
    pLockingStyle = &nolockIoMethods;
  }else{
    pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew);
#if SQLITE_ENABLE_LOCKING_STYLE
    /* Cache zFilename in the locking context (AFP and dotlock override) for
    ** proxyLock activation is possible (remote proxy is based on db name)
    ** zFilename remains valid until file is closed, to support */
................................................................................
#if OS_VXWORKS
  if( rc!=SQLITE_OK ){
    if( h>=0 ) robust_close(pNew, h, __LINE__);
    h = -1;
    osUnlink(zFilename);
    isDelete = 0;
  }
  pNew->isDelete = isDelete;
#endif
  if( rc!=SQLITE_OK ){
    if( h>=0 ) robust_close(pNew, h, __LINE__);
  }else{
    pNew->pMethod = pLockingStyle;
    OpenCounter(+1);
  }
................................................................................

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

  /* Check that the output buffer is large enough for the temporary file 
  ** name. If it is not, return SQLITE_ERROR.
  */
  if( (strlen(zDir) + strlen(SQLITE_TEMP_FILE_PREFIX) + 17) >= (size_t)nBuf ){
    return SQLITE_ERROR;
  }

  do{
    sqlite3_snprintf(nBuf-17, zBuf, "%s/"SQLITE_TEMP_FILE_PREFIX, zDir);
    j = (int)strlen(zBuf);
    sqlite3_randomness(15, &zBuf[j]);
    for(i=0; i<15; i++, j++){
      zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
    }
    zBuf[j] = 0;

  }while( osAccess(zBuf,0)==0 );
  return SQLITE_OK;
}

#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
/*
** Routine to transform a unixFile into a proxy-locking unixFile.
................................................................................
#if SQLITE_ENABLE_DATA_PROTECTION
  int eType = flags&0xFF0FFF00;  /* Type of file to open */
#else
  int eType = flags&0xFFFFFF00;  /* Type of file to open */
#endif
  int noLock;                    /* True to omit locking primitives */
  int rc = SQLITE_OK;            /* Function Return Code */


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

  /* If argument zPath is a NULL pointer, this function is required to open
  ** a temporary file. Use this buffer to store the file name in.
  */
  char zTmpname[MAX_PATHNAME+1];
  const char *zName = zPath;

  /* Check the following statements are true: 
  **
  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and 
  **   (b) if CREATE is set, then READWRITE must also be set, and
  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
................................................................................
    }else{
      pUnused = sqlite3_malloc(sizeof(*pUnused));
      if( !pUnused ){
        return SQLITE_NOMEM;
      }
    }
    p->pUnused = pUnused;






  }else if( !zName ){
    /* If zName is NULL, the upper layer is requesting a temp file. */
    assert(isDelete && !syncDir);
    rc = unixGetTempname(MAX_PATHNAME+1, zTmpname);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    zName = zTmpname;




  }

  /* Determine the value of the flags parameter passed to POSIX function
  ** open(). These must be calculated even if open() is not called, as
  ** they may be stored as part of the file handle and used by the 
  ** 'conch file' locking functions later on.  */
  if( isReadonly )  openFlags |= O_RDONLY;
................................................................................
    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
  }
  if (0 == strncmp("exfat", fsInfo.f_fstypename, 5)) {
    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
  }
#endif
  







#if SQLITE_ENABLE_LOCKING_STYLE
#if SQLITE_PREFER_PROXY_LOCKING
  isAutoProxy = 1;
#endif
  if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){
    char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
    int useProxy = 0;
................................................................................
        robust_close(p, fd, __LINE__);
        rc = SQLITE_IOERR_ACCESS;
        goto open_finished;
      }
      useProxy = !(fsInfo.f_flags&MNT_LOCAL);
    }
    if( useProxy ){
      rc = fillInUnixFile(pVfs, fd, syncDir, pFile, zPath, noLock,
                          isDelete, isReadonly);
      if( rc==SQLITE_OK ){
        /* cache the pMethod in case the transform fails */
        const struct sqlite3_io_methods *pMethod = pFile->pMethods;
        rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
        if( rc!=SQLITE_OK ){
          /* Use unixClose to clean up the resources added in fillInUnixFile 
          ** and clear all the structure's references.  Specifically, 
................................................................................
        }
      }
      goto open_finished;
    }
  }
#endif
  
  rc = fillInUnixFile(pVfs, fd, syncDir, pFile, zPath, noLock,
                      isDelete, isReadonly);
open_finished:
  if( rc!=SQLITE_OK ){
    sqlite3_free(p->pUnused);
  }
  return rc;
}

................................................................................
  int rc = SQLITE_OK;
  UNUSED_PARAMETER(NotUsed);
  SimulateIOError(return SQLITE_IOERR_DELETE);
  if( osUnlink(zPath)==(-1) && errno!=ENOENT ){
    return unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
  }
#ifndef SQLITE_DISABLE_DIRSYNC
  if( dirSync ){
    int fd;
    rc = osOpenDirectory(zPath, &fd);
    if( rc==SQLITE_OK ){
#if OS_VXWORKS
      if( fsync(fd)==-1 )
#else
      if( fsync(fd) )
................................................................................
  memset(&dummyVfs, 0, sizeof(dummyVfs));
  dummyVfs.pAppData = (void*)&autolockIoFinder;
  dummyVfs.zName = "dummy";
  pUnused->fd = fd;
  pUnused->flags = openFlags;
  pNew->pUnused = pUnused;
  
  rc = fillInUnixFile(&dummyVfs, fd, 0, (sqlite3_file*)pNew, path, 0, 0, 0);
  if( rc==SQLITE_OK ){
    *ppFile = pNew;
    return SQLITE_OK;
  }
end_create_proxy:    
  robust_close(pNew, fd, __LINE__);
  sqlite3_free(pNew);

#if SQLITE_ENABLE_DATA_PROTECTION
  int protFlags;                      /* Data protection flags from unixOpen */
#endif
#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
  unsigned fsFlags;                   /* cached details from statfs() */
#endif
#if OS_VXWORKS

  struct vxworksFileId *pId;          /* Unique file ID */
#endif
#ifndef NDEBUG
  /* The next group of variables are used to track whether or not the
  ** transaction counter in bytes 24-27 of database files are updated
  ** whenever any part of the database changes.  An assertion fault will
  ** occur if a file is updated without also updating the transaction
................................................................................
#define UNIXFILE_PERSIST_WAL 0x04     /* Persistent WAL mode */
#ifndef SQLITE_DISABLE_DIRSYNC
# define UNIXFILE_DIRSYNC    0x08     /* Directory sync needed */
#else
# define UNIXFILE_DIRSYNC    0x00
#endif
#define UNIXFILE_PSOW        0x10     /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
#define UNIXFILE_DELETE      0x20     /* Delete on close */
#define UNIXFILE_URI         0x40     /* Filename might have query parameters */
#define UNIXFILE_NOLOCK      0x80     /* Do no file locking */

/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"

/*
................................................................................
  if( pFile->h>=0 ){
    robust_close(pFile, pFile->h, __LINE__);
    pFile->h = -1;
  }
#endif
#if OS_VXWORKS
  if( pFile->pId ){
    if( pFile->ctrlFlags & UNIXFILE_DELETE ){
      osUnlink(pFile->pId->zCanonicalName);
    }
    vxworksReleaseFileId(pFile->pId);
    pFile->pId = 0;
  }
#endif
  OSTRACE(("CLOSE   %-3d\n", pFile->h));
................................................................................
    */
    case SQLITE_FCNTL_DB_UNCHANGED: {
      ((unixFile*)id)->dbUpdate = 0;
      return SQLITE_OK;
    }
#endif
#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
    case SQLITE_SET_LOCKPROXYFILE:
    case SQLITE_GET_LOCKPROXYFILE: {
      return proxyFileControl(id,op,pArg);
    }
#endif /* SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__) */
#if (SQLITE_ENABLE_APPLE_SPI>0) && defined(__APPLE__)
    case SQLITE_FCNTL_TRUNCATE_DATABASE: {
      return unixTruncateDatabase(pFile, (pArg ? (*(int *)pArg) : 0));
    }
................................................................................
      }
      pLockstate = (LockstatePID *)pArg;
      rc = unixLockstatePid(pFile, pLockstate->pid, &(pLockstate->state));
      return rc;
    }
      
#endif /* (SQLITE_ENABLE_APPLE_SPI>0) && defined(__APPLE__) */



  }
  return SQLITE_NOTFOUND;
}

/*
** Return the sector size in bytes of the underlying block device for
** the specified file. This is almost always 512 bytes, but may be
................................................................................
    nShmFilename = 6 + (int)strlen(zBasePath);
#endif
    pShmNode = sqlite3_malloc( sizeof(*pShmNode) + nShmFilename );
    if( pShmNode==0 ){
      rc = SQLITE_NOMEM;
      goto shm_open_err;
    }
    memset(pShmNode, 0, sizeof(*pShmNode)+nShmFilename);
    zShmFilename = pShmNode->zFilename = (char*)&pShmNode[1];
#ifdef SQLITE_SHM_DIRECTORY
    sqlite3_snprintf(nShmFilename, zShmFilename, 
                     SQLITE_SHM_DIRECTORY "/sqlite-shm-%x-%x",
                     (u32)sStat.st_ino, (u32)sStat.st_dev);
#else
    sqlite3_snprintf(nShmFilename, zShmFilename, "%s-shm", zBasePath);
................................................................................

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

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



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

  assert( pNew->pInode==NULL );






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

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

  OSTRACE(("OPEN    %-3d %s\n", h, zFilename));
  pNew->h = h;
  pNew->pVfs = pVfs;
  pNew->zPath = zFilename;
  pNew->ctrlFlags = (u8)ctrlFlags;
  if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0),
                           "psow", SQLITE_POWERSAFE_OVERWRITE) ){
    pNew->ctrlFlags |= UNIXFILE_PSOW;
  }
  if( memcmp(pVfs->zName,"unix-excl",10)==0 ){
    pNew->ctrlFlags |= UNIXFILE_EXCL;
  }







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

  if( ctrlFlags & UNIXFILE_NOLOCK ){
    pLockingStyle = &nolockIoMethods;
  }else{
    pLockingStyle = (**(finder_type*)pVfs->pAppData)(zFilename, pNew);
#if SQLITE_ENABLE_LOCKING_STYLE
    /* Cache zFilename in the locking context (AFP and dotlock override) for
    ** proxyLock activation is possible (remote proxy is based on db name)
    ** zFilename remains valid until file is closed, to support */
................................................................................
#if OS_VXWORKS
  if( rc!=SQLITE_OK ){
    if( h>=0 ) robust_close(pNew, h, __LINE__);
    h = -1;
    osUnlink(zFilename);
    isDelete = 0;
  }
  if( isDelete ) pNew->ctrlFlags |= UNIXFILE_DELETE;
#endif
  if( rc!=SQLITE_OK ){
    if( h>=0 ) robust_close(pNew, h, __LINE__);
  }else{
    pNew->pMethod = pLockingStyle;
    OpenCounter(+1);
  }
................................................................................

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

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

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

#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
/*
** Routine to transform a unixFile into a proxy-locking unixFile.
................................................................................
#if SQLITE_ENABLE_DATA_PROTECTION
  int eType = flags&0xFF0FFF00;  /* Type of file to open */
#else
  int eType = flags&0xFFFFFF00;  /* Type of file to open */
#endif
  int noLock;                    /* True to omit locking primitives */
  int rc = SQLITE_OK;            /* Function Return Code */
  int ctrlFlags = 0;             /* UNIXFILE_* flags */

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

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

  /* Check the following statements are true: 
  **
  **   (a) Exactly one of the READWRITE and READONLY flags must be set, and 
  **   (b) if CREATE is set, then READWRITE must also be set, and
  **   (c) if EXCLUSIVE is set, then CREATE must also be set.
................................................................................
    }else{
      pUnused = sqlite3_malloc(sizeof(*pUnused));
      if( !pUnused ){
        return SQLITE_NOMEM;
      }
    }
    p->pUnused = pUnused;

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

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

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

  /* Determine the value of the flags parameter passed to POSIX function
  ** open(). These must be calculated even if open() is not called, as
  ** they may be stored as part of the file handle and used by the 
  ** 'conch file' locking functions later on.  */
  if( isReadonly )  openFlags |= O_RDONLY;
................................................................................
    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
  }
  if (0 == strncmp("exfat", fsInfo.f_fstypename, 5)) {
    ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
  }
#endif

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

#if SQLITE_ENABLE_LOCKING_STYLE
#if SQLITE_PREFER_PROXY_LOCKING
  isAutoProxy = 1;
#endif
  if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){
    char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
    int useProxy = 0;
................................................................................
        robust_close(p, fd, __LINE__);
        rc = SQLITE_IOERR_ACCESS;
        goto open_finished;
      }
      useProxy = !(fsInfo.f_flags&MNT_LOCAL);
    }
    if( useProxy ){
      rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);

      if( rc==SQLITE_OK ){
        /* cache the pMethod in case the transform fails */
        const struct sqlite3_io_methods *pMethod = pFile->pMethods;
        rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
        if( rc!=SQLITE_OK ){
          /* Use unixClose to clean up the resources added in fillInUnixFile 
          ** and clear all the structure's references.  Specifically, 
................................................................................
        }
      }
      goto open_finished;
    }
  }
#endif
  
  rc = fillInUnixFile(pVfs, fd, pFile, zPath, ctrlFlags);

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

................................................................................
  int rc = SQLITE_OK;
  UNUSED_PARAMETER(NotUsed);
  SimulateIOError(return SQLITE_IOERR_DELETE);
  if( osUnlink(zPath)==(-1) && errno!=ENOENT ){
    return unixLogError(SQLITE_IOERR_DELETE, "unlink", zPath);
  }
#ifndef SQLITE_DISABLE_DIRSYNC
  if( (dirSync & 1)!=0 ){
    int fd;
    rc = osOpenDirectory(zPath, &fd);
    if( rc==SQLITE_OK ){
#if OS_VXWORKS
      if( fsync(fd)==-1 )
#else
      if( fsync(fd) )
................................................................................
  memset(&dummyVfs, 0, sizeof(dummyVfs));
  dummyVfs.pAppData = (void*)&autolockIoFinder;
  dummyVfs.zName = "dummy";
  pUnused->fd = fd;
  pUnused->flags = openFlags;
  pNew->pUnused = pUnused;
  
  rc = fillInUnixFile(&dummyVfs, fd, (sqlite3_file*)pNew, path, 0);
  if( rc==SQLITE_OK ){
    *ppFile = pNew;
    return SQLITE_OK;
  }
end_create_proxy:    
  robust_close(pNew, fd, __LINE__);
  sqlite3_free(pNew);

      winModeBit(pFile, WINFILE_PSOW, (int*)pArg);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_VFSNAME: {
      *(char**)pArg = sqlite3_mprintf("win32");
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_SYNC_OMITTED: {
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_WIN32_AV_RETRY: {
      int *a = (int*)pArg;
      if( a[0]>0 ){
        win32IoerrRetry = a[0];
      }else{
        a[0] = win32IoerrRetry;
      }
................................................................................
      if( p->hFile.h != INVALID_HANDLE_VALUE ){
        SimulateIOErrorBenign(1);
        winClose((sqlite3_file *)&p->hFile);
        SimulateIOErrorBenign(0);
      }
      if( deleteFlag ){
        SimulateIOErrorBenign(1);

        winDelete(pVfs, p->zFilename, 0);

        SimulateIOErrorBenign(0);
      }
      *pp = p->pNext;
      sqlite3_free(p->aRegion);
      sqlite3_free(p);
    }else{
      pp = &p->pNext;
................................................................................
  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new winShmNode and filename.
  */
  p = sqlite3_malloc( sizeof(*p) );
  if( p==0 ) return SQLITE_IOERR_NOMEM;
  memset(p, 0, sizeof(*p));
  nName = sqlite3Strlen30(pDbFd->zPath);
  pNew = sqlite3_malloc( sizeof(*pShmNode) + nName + 16 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_IOERR_NOMEM;
  }
  memset(pNew, 0, sizeof(*pNew));
  pNew->zFilename = (char*)&pNew[1];
  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename); 

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

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

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
................................................................................
*/
static int getTempname(int nBuf, char *zBuf){
  static char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  size_t i, j;
  char zTempPath[MAX_PATH+1];

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

................................................................................
    }
#endif
  }

  /* Check that the output buffer is large enough for the temporary file 
  ** name. If it is not, return SQLITE_ERROR.
  */
  if( (sqlite3Strlen30(zTempPath) + sqlite3Strlen30(SQLITE_TEMP_FILE_PREFIX) + 17) >= nBuf ){
    return SQLITE_ERROR;
  }

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

  sqlite3_snprintf(nBuf-17, zBuf,
                   "%s\\"SQLITE_TEMP_FILE_PREFIX, zTempPath);
  j = sqlite3Strlen30(zBuf);
  sqlite3_randomness(15, &zBuf[j]);
  for(i=0; i<15; i++, j++){
    zBuf[j] = (char)zChars[ ((unsigned char)zBuf[j])%(sizeof(zChars)-1) ];
  }
  zBuf[j] = 0;


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

/*
** Open a file.
................................................................................
  void *zConverted;              /* Filename in OS encoding */
  const char *zUtf8Name = zName; /* Filename in UTF-8 encoding */
  int cnt = 0;

  /* If argument zPath is a NULL pointer, this function is required to open
  ** a temporary file. Use this buffer to store the file name in.
  */
  char zTmpname[MAX_PATH+1];     /* Buffer used to create temp filename */

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

  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
................................................................................
  pFile->h = INVALID_HANDLE_VALUE;

  /* If the second argument to this function is NULL, generate a 
  ** temporary file name to use 
  */
  if( !zUtf8Name ){
    assert(isDelete && !isOpenJournal);
    rc = getTempname(MAX_PATH+1, zTmpname);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    zUtf8Name = zTmpname;
  }








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

      winModeBit(pFile, WINFILE_PSOW, (int*)pArg);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_VFSNAME: {
      *(char**)pArg = sqlite3_mprintf("win32");
      return SQLITE_OK;
    }



    case SQLITE_FCNTL_WIN32_AV_RETRY: {
      int *a = (int*)pArg;
      if( a[0]>0 ){
        win32IoerrRetry = a[0];
      }else{
        a[0] = win32IoerrRetry;
      }
................................................................................
      if( p->hFile.h != INVALID_HANDLE_VALUE ){
        SimulateIOErrorBenign(1);
        winClose((sqlite3_file *)&p->hFile);
        SimulateIOErrorBenign(0);
      }
      if( deleteFlag ){
        SimulateIOErrorBenign(1);
        sqlite3BeginBenignMalloc();
        winDelete(pVfs, p->zFilename, 0);
        sqlite3EndBenignMalloc();
        SimulateIOErrorBenign(0);
      }
      *pp = p->pNext;
      sqlite3_free(p->aRegion);
      sqlite3_free(p);
    }else{
      pp = &p->pNext;
................................................................................
  /* Allocate space for the new sqlite3_shm object.  Also speculatively
  ** allocate space for a new winShmNode and filename.
  */
  p = sqlite3_malloc( sizeof(*p) );
  if( p==0 ) return SQLITE_IOERR_NOMEM;
  memset(p, 0, sizeof(*p));
  nName = sqlite3Strlen30(pDbFd->zPath);
  pNew = sqlite3_malloc( sizeof(*pShmNode) + nName + 17 );
  if( pNew==0 ){
    sqlite3_free(p);
    return SQLITE_IOERR_NOMEM;
  }
  memset(pNew, 0, sizeof(*pNew) + nName + 17);
  pNew->zFilename = (char*)&pNew[1];
  sqlite3_snprintf(nName+15, pNew->zFilename, "%s-shm", pDbFd->zPath);
  sqlite3FileSuffix3(pDbFd->zPath, pNew->zFilename); 

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

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

      goto shm_open_err;
    }

    /* Check to see if another process is holding the dead-man switch.
    ** If not, truncate the file to zero length. 
    */
    if( winShmSystemLock(pShmNode, _SHM_WRLCK, WIN_SHM_DMS, 1)==SQLITE_OK ){
................................................................................
*/
static int getTempname(int nBuf, char *zBuf){
  static char zChars[] =
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789";
  size_t i, j;
  char zTempPath[MAX_PATH+2];

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

................................................................................
    }
#endif
  }

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

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

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

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

/*
** Open a file.
................................................................................
  void *zConverted;              /* Filename in OS encoding */
  const char *zUtf8Name = zName; /* Filename in UTF-8 encoding */
  int cnt = 0;

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

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

  int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
................................................................................
  pFile->h = INVALID_HANDLE_VALUE;

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

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

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

    assert( pPager->eLock==EXCLUSIVE_LOCK );
    /* TODO: Is it safe to use Pager.dbFileSize here? */
    rc = sqlite3OsFileSize(pPager->fd, &currentSize);
    newSize = szPage*(i64)nPage;
    if( rc==SQLITE_OK && currentSize!=newSize ){
      if( currentSize>newSize ){
        rc = sqlite3OsTruncate(pPager->fd, newSize);
      }else{
        char *pTmp = pPager->pTmpSpace;
        memset(pTmp, 0, szPage);
        testcase( (newSize-szPage) <  currentSize );
        testcase( (newSize-szPage) == currentSize );
        testcase( (newSize-szPage) >  currentSize );
        rc = sqlite3OsWrite(pPager->fd, pTmp, szPage, newSize-szPage);
      }
      if( rc==SQLITE_OK ){
        pPager->dbFileSize = nPage;
      }
................................................................................

end_playback:
  /* Following a rollback, the database file should be back in its original
  ** state prior to the start of the transaction, so invoke the
  ** SQLITE_FCNTL_DB_UNCHANGED file-control method to disable the
  ** assertion that the transaction counter was modified.
  */
  assert(
    pPager->fd->pMethods==0 ||
    sqlite3OsFileControl(pPager->fd,SQLITE_FCNTL_DB_UNCHANGED,0)>=SQLITE_OK
  );



  /* If this playback is happening automatically as a result of an IO or 
  ** malloc error that occurred after the change-counter was updated but 
  ** before the transaction was committed, then the change-counter 
  ** modification may just have been reverted. If this happens in exclusive 
  ** mode, then subsequent transactions performed by the connection will not
  ** update the change-counter at all. This may lead to cache inconsistency
................................................................................
    assert( isOpen(pPager->fd) || pPager->tempFile );
    if( isOpen(pPager->fd) ){
      int rc = sqlite3OsFileSize(pPager->fd, &n);
      if( rc!=SQLITE_OK ){
        return rc;
      }
    }
    nPage = (Pgno)(n / pPager->pageSize);
    if( nPage==0 && n>0 ){
      nPage = 1;
    }
  }

  /* If the current number of pages in the file is greater than the
  ** configured maximum pager number, increase the allowed limit so
  ** that the file can be read.
  */
  if( nPage>pPager->mxPgno ){
................................................................................
    if( rc==SQLITE_OK ){
      pNew = (char *)sqlite3PageMalloc(pageSize);
      if( !pNew ) rc = SQLITE_NOMEM;
    }

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

................................................................................

  /* Before the first write, give the VFS a hint of what the final
  ** file size will be.
  */
  assert( rc!=SQLITE_OK || isOpen(pPager->fd) );
  if( rc==SQLITE_OK && pPager->dbSize>pPager->dbHintSize ){
    sqlite3_int64 szFile = pPager->pageSize * (sqlite3_int64)pPager->dbSize;
    sqlite3BeginBenignMalloc();
    sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
    sqlite3EndBenignMalloc();
    pPager->dbHintSize = pPager->dbSize;
  }

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

    /* If there are dirty pages in the page cache with page numbers greater
................................................................................
      return rc;
    }
  }else{
    rc = pager_playback(pPager, 0);
  }

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


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

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

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

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

  }
#endif

  /* If this playback is happening automatically as a result of an IO or 
  ** malloc error that occurred after the change-counter was updated but 
  ** before the transaction was committed, then the change-counter 
  ** modification may just have been reverted. If this happens in exclusive 
  ** mode, then subsequent transactions performed by the connection will not
  ** update the change-counter at all. This may lead to cache inconsistency
................................................................................
    assert( isOpen(pPager->fd) || pPager->tempFile );
    if( isOpen(pPager->fd) ){
      int rc = sqlite3OsFileSize(pPager->fd, &n);
      if( rc!=SQLITE_OK ){
        return rc;
      }
    }
    nPage = (Pgno)((n+pPager->pageSize-1) / pPager->pageSize);



  }

  /* If the current number of pages in the file is greater than the
  ** configured maximum pager number, increase the allowed limit so
  ** that the file can be read.
  */
  if( nPage>pPager->mxPgno ){
................................................................................
    if( rc==SQLITE_OK ){
      pNew = (char *)sqlite3PageMalloc(pageSize);
      if( !pNew ) rc = SQLITE_NOMEM;
    }

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

................................................................................

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

    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);

    pPager->dbHintSize = pPager->dbSize;
  }

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

    /* If there are dirty pages in the page cache with page numbers greater
................................................................................
      return rc;
    }
  }else{
    rc = pager_playback(pPager, 0);
  }

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

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

**
**   (2)  There is a single global PGroup that all PCaches are a member
**        of.
**
** Mode 1 uses more memory (since PCache instances are not able to rob
** unused pages from other PCaches) but it also operates without a mutex,
** and is therefore often faster.  Mode 2 requires a mutex in order to be
** threadsafe, but is able recycle pages more efficient.
**
** For mode (1), PGroup.mutex is NULL.  For mode (2) there is only a single
** PGroup which is the pcache1.grp global variable and its mutex is
** SQLITE_MUTEX_STATIC_LRU.
*/
struct PGroup {
  sqlite3_mutex *mutex;          /* MUTEX_STATIC_LRU or NULL */
................................................................................
**
** Pointers to structures of this type are cast and returned as 
** opaque sqlite3_pcache* handles.
*/
struct PCache1 {
  /* Cache configuration parameters. Page size (szPage) and the purgeable
  ** flag (bPurgeable) are set when the cache is created. nMax may be 
  ** modified at any time by a call to the pcache1CacheSize() method.
  ** The PGroup mutex must be held when accessing nMax.
  */
  PGroup *pGroup;                     /* PGroup this cache belongs to */
  int szPage;                         /* Size of allocated pages in bytes */
  int szExtra;                        /* Size of extra space in bytes */
  int bPurgeable;                     /* True if cache is purgeable */
  unsigned int nMin;                  /* Minimum number of pages reserved */
................................................................................
** If memory was allocated specifically to the page cache using
** SQLITE_CONFIG_PAGECACHE but that memory has all been used, then
** it is desirable to avoid allocating a new page cache entry because
** presumably SQLITE_CONFIG_PAGECACHE was suppose to be sufficient
** for all page cache needs and we should not need to spill the
** allocation onto the heap.
**
** Or, the heap is used for all page cache memory put the heap is
** under memory pressure, then again it is desirable to avoid
** allocating a new page cache entry in order to avoid stressing
** the heap even further.
*/
static int pcache1UnderMemoryPressure(PCache1 *pCache){
  if( pcache1.nSlot && (pCache->szPage+pCache->szExtra)<=pcache1.szSlot ){
    return pcache1.bUnderPressure;
................................................................................
** the value of the createFlag argument.  0 means do not allocate a new
** page.  1 means allocate a new page if space is easily available.  2 
** means to try really hard to allocate a new page.
**
** For a non-purgeable cache (a cache used as the storage for an in-memory
** database) there is really no difference between createFlag 1 and 2.  So
** the calling function (pcache.c) will never have a createFlag of 1 on
** a non-purgable cache.
**
** There are three different approaches to obtaining space for a page,
** depending on the value of parameter createFlag (which may be 0, 1 or 2).
**
**   1. Regardless of the value of createFlag, the cache is searched for a 
**      copy of the requested page. If one is found, it is returned.
**

**
**   (2)  There is a single global PGroup that all PCaches are a member
**        of.
**
** Mode 1 uses more memory (since PCache instances are not able to rob
** unused pages from other PCaches) but it also operates without a mutex,
** and is therefore often faster.  Mode 2 requires a mutex in order to be
** threadsafe, but recycles pages more efficiently.
**
** For mode (1), PGroup.mutex is NULL.  For mode (2) there is only a single
** PGroup which is the pcache1.grp global variable and its mutex is
** SQLITE_MUTEX_STATIC_LRU.
*/
struct PGroup {
  sqlite3_mutex *mutex;          /* MUTEX_STATIC_LRU or NULL */
................................................................................
**
** Pointers to structures of this type are cast and returned as 
** opaque sqlite3_pcache* handles.
*/
struct PCache1 {
  /* Cache configuration parameters. Page size (szPage) and the purgeable
  ** flag (bPurgeable) are set when the cache is created. nMax may be 
  ** modified at any time by a call to the pcache1Cachesize() method.
  ** The PGroup mutex must be held when accessing nMax.
  */
  PGroup *pGroup;                     /* PGroup this cache belongs to */
  int szPage;                         /* Size of allocated pages in bytes */
  int szExtra;                        /* Size of extra space in bytes */
  int bPurgeable;                     /* True if cache is purgeable */
  unsigned int nMin;                  /* Minimum number of pages reserved */
................................................................................
** If memory was allocated specifically to the page cache using
** SQLITE_CONFIG_PAGECACHE but that memory has all been used, then
** it is desirable to avoid allocating a new page cache entry because
** presumably SQLITE_CONFIG_PAGECACHE was suppose to be sufficient
** for all page cache needs and we should not need to spill the
** allocation onto the heap.
**
** Or, the heap is used for all page cache memory but the heap is
** under memory pressure, then again it is desirable to avoid
** allocating a new page cache entry in order to avoid stressing
** the heap even further.
*/
static int pcache1UnderMemoryPressure(PCache1 *pCache){
  if( pcache1.nSlot && (pCache->szPage+pCache->szExtra)<=pcache1.szSlot ){
    return pcache1.bUnderPressure;
................................................................................
** the value of the createFlag argument.  0 means do not allocate a new
** page.  1 means allocate a new page if space is easily available.  2 
** means to try really hard to allocate a new page.
**
** For a non-purgeable cache (a cache used as the storage for an in-memory
** database) there is really no difference between createFlag 1 and 2.  So
** the calling function (pcache.c) will never have a createFlag of 1 on
** a non-purgeable cache.
**
** There are three different approaches to obtaining space for a page,
** depending on the value of parameter createFlag (which may be 0, 1 or 2).
**
**   1. Regardless of the value of createFlag, the cache is searched for a 
**      copy of the requested page. If one is found, it is returned.
**

   **
   */
  if( sqlite3StrICmp(zLeft, "lock_proxy_file")==0 ){
    if( !zRight ){
      Pager *pPager = sqlite3BtreePager(pDb->pBt);
      char *proxy_file_path = NULL;
      sqlite3_file *pFile = sqlite3PagerFile(pPager);
      sqlite3OsFileControl(pFile, SQLITE_GET_LOCKPROXYFILE, 
                           &proxy_file_path);
      
      if( proxy_file_path ){
        sqlite3VdbeSetNumCols(v, 1);
        sqlite3VdbeSetColName(v, 0, COLNAME_NAME, 
                              "lock_proxy_file", SQLITE_STATIC);
        sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, proxy_file_path, 0);

   **
   */
  if( sqlite3StrICmp(zLeft, "lock_proxy_file")==0 ){
    if( !zRight ){
      Pager *pPager = sqlite3BtreePager(pDb->pBt);
      char *proxy_file_path = NULL;
      sqlite3_file *pFile = sqlite3PagerFile(pPager);
      sqlite3OsFileControlHint(pFile, SQLITE_GET_LOCKPROXYFILE, 
                           &proxy_file_path);
      
      if( proxy_file_path ){
        sqlite3VdbeSetNumCols(v, 1);
        sqlite3VdbeSetColName(v, 0, COLNAME_NAME, 
                              "lock_proxy_file", SQLITE_STATIC);
        sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, proxy_file_path, 0);

/*
** CAPI3REF: Obtain Values For URI Parameters
**
** These are utility routines, useful to VFS implementations, that check
** to see if a database file was a URI that contained a specific query 
** parameter, and if so obtains the value of that query parameter.
**
** If F is the filename pointer passed into the xOpen() method of a VFS


** implementation and P is the name of the query parameter, then
** sqlite3_uri_parameter(F,P) returns the value of the P
** parameter if it exists or a NULL pointer if P does not appear as a 
** query parameter on F.  If P is a query parameter of F
** has no explicit value, then sqlite3_uri_parameter(F,P) returns
** a pointer to an empty string.
**
** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
................................................................................
** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
** 64-bit signed integer and returns that integer, or D if P does not
** exist.  If the value of P is something other than an integer, then
** zero is returned.
** 
** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
** is not a pathname pointer that SQLite passed into the xOpen VFS method,
** then the behavior of this routine is undefined and probably undesirable.

*/
const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);


/*
................................................................................
** The SQLite source code contains multiple implementations
** of these mutex routines.  An appropriate implementation
** is selected automatically at compile-time.  ^(The following
** implementations are available in the SQLite core:
**
** <ul>
** <li>   SQLITE_MUTEX_OS2
** <li>   SQLITE_MUTEX_PTHREAD
** <li>   SQLITE_MUTEX_W32
** <li>   SQLITE_MUTEX_NOOP
** </ul>)^
**
** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
** that does no real locking and is appropriate for use in
** a single-threaded application.  ^The SQLITE_MUTEX_OS2,
** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
** are appropriate for use on OS/2, Unix, and Windows.
**
** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
** implementation is included with the library. In this case the
** application must supply a custom mutex implementation using the
** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
................................................................................
** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
** handle invalid, and will not use it with any other sqlite3_pcache_methods2
** functions.
**
** [[the xShrink() page cache method]]
** ^SQLite invokes the xShrink() method when it wants the page cache to
** free up as much of heap memory as possible.  The page cache implementation
** is not obligated to free any memory, but well-behaved implementions should
** do their best.
*/
typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
struct sqlite3_pcache_methods2 {
  int iVersion;
  void *pArg;
  int (*xInit)(void*);

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


/*
................................................................................
** The SQLite source code contains multiple implementations
** of these mutex routines.  An appropriate implementation
** is selected automatically at compile-time.  ^(The following
** implementations are available in the SQLite core:
**
** <ul>
** <li>   SQLITE_MUTEX_OS2
** <li>   SQLITE_MUTEX_PTHREADS
** <li>   SQLITE_MUTEX_W32
** <li>   SQLITE_MUTEX_NOOP
** </ul>)^
**
** ^The SQLITE_MUTEX_NOOP implementation is a set of routines
** that does no real locking and is appropriate for use in
** a single-threaded application.  ^The SQLITE_MUTEX_OS2,
** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations
** are appropriate for use on OS/2, Unix, and Windows.
**
** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
** implementation is included with the library. In this case the
** application must supply a custom mutex implementation using the
** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
................................................................................
** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
** handle invalid, and will not use it with any other sqlite3_pcache_methods2
** functions.
**
** [[the xShrink() page cache method]]
** ^SQLite invokes the xShrink() method when it wants the page cache to
** free up as much of heap memory as possible.  The page cache implementation
** is not obligated to free any memory, but well-behaved implementations should
** do their best.
*/
typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
struct sqlite3_pcache_methods2 {
  int iVersion;
  void *pArg;
  int (*xInit)(void*);

      Tcl_AppendResult(interp, "unknown option: ", zArg, (char*)0);
      return TCL_ERROR;
    }
  }
  if( objc<3 || (objc&1)!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv, 
      "HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN?"
      " ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN?"
#ifdef SQLITE_HAS_CODEC
      " ?-key CODECKEY?"
#endif
    );
    return TCL_ERROR;
  }
  zErrMsg = 0;

      Tcl_AppendResult(interp, "unknown option: ", zArg, (char*)0);
      return TCL_ERROR;
    }
  }
  if( objc<3 || (objc&1)!=1 ){
    Tcl_WrongNumArgs(interp, 1, objv, 
      "HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN?"
      " ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN?"
#ifdef SQLITE_HAS_CODEC
      " ?-key CODECKEY?"
#endif
    );
    return TCL_ERROR;
  }
  zErrMsg = 0;

  const char **argv      /* Text of each argument */
){
  sqlite3_vfs *pVfs;
  sqlite3_file *fd = 0;
  int rc;
  int n;
  i64 offset;


  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " N-MEGABYTES FILE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], &n) ) return TCL_ERROR;

  pVfs = sqlite3_vfs_find(0);





  rc = sqlite3OsOpenMalloc(pVfs, argv[2], &fd, 
      (SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB), 0
  );
  if( rc ){
    Tcl_AppendResult(interp, "open failed: ", errorName(rc), 0);

    return TCL_ERROR;
  }
  offset = n;
  offset *= 1024*1024;
  rc = sqlite3OsWrite(fd, "Hello, World!", 14, offset);
  sqlite3OsCloseFree(fd);

  if( rc ){
    Tcl_AppendResult(interp, "write failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}
#endif

  const char **argv      /* Text of each argument */
){
  sqlite3_vfs *pVfs;
  sqlite3_file *fd = 0;
  int rc;
  int n;
  i64 offset;
  char *zFile;
  int nFile;
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " N-MEGABYTES FILE\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], &n) ) return TCL_ERROR;

  pVfs = sqlite3_vfs_find(0);
  nFile = strlen(argv[2]);
  zFile = sqlite3_malloc( nFile+2 );
  if( zFile==0 ) return TCL_ERROR;
  memcpy(zFile, argv[2], nFile+1);
  zFile[nFile+1] = 0;
  rc = sqlite3OsOpenMalloc(pVfs, zFile, &fd, 
      (SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_DB), 0
  );
  if( rc ){
    Tcl_AppendResult(interp, "open failed: ", errorName(rc), 0);
    sqlite3_free(zFile);
    return TCL_ERROR;
  }
  offset = n;
  offset *= 1024*1024;
  rc = sqlite3OsWrite(fd, "Hello, World!", 14, offset);
  sqlite3OsCloseFree(fd);
  sqlite3_free(zFile);
  if( rc ){
    Tcl_AppendResult(interp, "write failed: ", errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}
#endif

  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  Btree *pBt;
  int rc, nCache;
  char zBuf[100];


  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME NCACHE FLAGS\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[2], &nCache) ) return TCL_ERROR;
  nRefSqlite3++;
  if( nRefSqlite3==1 ){
    sDb.pVfs = sqlite3_vfs_find(0);
    sDb.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
    sqlite3_mutex_enter(sDb.mutex);
  }





  rc = sqlite3BtreeOpen(sDb.pVfs, argv[1], &sDb, &pBt, 0, 
     SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_MAIN_DB);

  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sqlite3BtreeSetCacheSize(pBt, nCache);
  sqlite3_snprintf(sizeof(zBuf), zBuf,"%p", pBt);
  Tcl_AppendResult(interp, zBuf, 0);

  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  Btree *pBt;
  int rc, nCache;
  char zBuf[100];
  int n;
  char *zFilename;
  if( argc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " FILENAME NCACHE FLAGS\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[2], &nCache) ) return TCL_ERROR;
  nRefSqlite3++;
  if( nRefSqlite3==1 ){
    sDb.pVfs = sqlite3_vfs_find(0);
    sDb.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
    sqlite3_mutex_enter(sDb.mutex);
  }
  n = strlen(argv[1]);
  zFilename = sqlite3_malloc( n+2 );
  if( zFilename==0 ) return TCL_ERROR;
  memcpy(zFilename, argv[1], n+1);
  zFilename[n+1] = 0;
  rc = sqlite3BtreeOpen(sDb.pVfs, zFilename, &sDb, &pBt, 0, 
     SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_MAIN_DB);
  sqlite3_free(zFilename);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sqlite3BtreeSetCacheSize(pBt, nCache);
  sqlite3_snprintf(sizeof(zBuf), zBuf,"%p", pBt);
  Tcl_AppendResult(interp, zBuf, 0);

    if( rc==SQLITE_OK ){
      int ii;
      for(ii=0; rc==SQLITE_OK && ii<pMain->nPage; ii++){
        i64 iOff = (i64)(pMain->nPagesize) * (i64)ii;
        if( iOff==PENDING_BYTE ) continue;
        rc = sqlite3OsRead(pMain->pReal, aData, pMain->nPagesize, iOff);
        pMain->aCksum[ii] = genCksum(aData, pMain->nPagesize);

      }
    }

    start_ioerr_simulation(iSave, iSave2);
  }

  sqlite3_free(aData);
................................................................................
}

/*
** File control method. For custom operations on an jt-file.
*/
static int jtFileControl(sqlite3_file *pFile, int op, void *pArg){
  jt_file *p = (jt_file *)pFile;
  return sqlite3OsFileControl(p->pReal, op, pArg);
}

/*
** Return the sector-size in bytes for an jt-file.
*/
static int jtSectorSize(sqlite3_file *pFile){
  jt_file *p = (jt_file *)pFile;

    if( rc==SQLITE_OK ){
      int ii;
      for(ii=0; rc==SQLITE_OK && ii<pMain->nPage; ii++){
        i64 iOff = (i64)(pMain->nPagesize) * (i64)ii;
        if( iOff==PENDING_BYTE ) continue;
        rc = sqlite3OsRead(pMain->pReal, aData, pMain->nPagesize, iOff);
        pMain->aCksum[ii] = genCksum(aData, pMain->nPagesize);
        if( ii+1==pMain->nPage && rc==SQLITE_IOERR_SHORT_READ ) rc = SQLITE_OK;
      }
    }

    start_ioerr_simulation(iSave, iSave2);
  }

  sqlite3_free(aData);
................................................................................
}

/*
** File control method. For custom operations on an jt-file.
*/
static int jtFileControl(sqlite3_file *pFile, int op, void *pArg){
  jt_file *p = (jt_file *)pFile;
  return p->pReal->pMethods->xFileControl(p->pReal, op, pArg);
}

/*
** Return the sector-size in bytes for an jt-file.
*/
static int jtSectorSize(sqlite3_file *pFile){
  jt_file *p = (jt_file *)pFile;

  while( *z2 ){ z2++; }
  return 0x3fffffff & (int)(z2 - z);
}

/*
** Generate the file-name for chunk iChunk of the group with base name
** zBase. The file-name is written to buffer zOut before returning. Buffer
** zOut must be allocated by the caller so that it is at least (nBase+4)
** bytes in size, where nBase is the length of zBase, not including the
** nul-terminator.


















*/
static void multiplexFilename(
  const char *zBase,              /* Filename for chunk 0 */
  int nBase,                      /* Size of zBase in bytes (without \0) */
  int flags,                      /* Flags used to open file */
  int iChunk,                     /* Chunk to generate filename for */
  char *zOut                      /* Buffer to write generated name to */
){

  memcpy(zOut, zBase, nBase+1);
  if( iChunk!=0 && iChunk!=SQLITE_MULTIPLEX_JOURNAL_8_3_OFFSET ){
    int n = nBase;
#ifdef SQLITE_ENABLE_8_3_NAMES
    int i;
    for(i=n-1; i>0 && i>=n-4 && zOut[i]!='.'; i--){}
    if( i>=n-4 ) n = i+1;
    if( flags & SQLITE_OPEN_MAIN_JOURNAL ){
      /* The extensions on overflow files for main databases are 001, 002,
       ** 003 and so forth.  To avoid name collisions, add 400 to the 
       ** extensions of journal files so that they are 401, 402, 403, ....
       */
      iChunk += SQLITE_MULTIPLEX_JOURNAL_8_3_OFFSET;
    }
#endif
    sqlite3_snprintf(4,&zOut[n],"%03d",iChunk);

  }



}

/* Compute the filename for the iChunk-th chunk
*/
static int multiplexSubFilename(multiplexGroup *pGroup, int iChunk){
  if( iChunk>=pGroup->nReal ){
    struct multiplexReal *p;
................................................................................
    memset(&p[pGroup->nReal], 0, sizeof(p[0])*(iChunk+1-pGroup->nReal));
    pGroup->aReal = p;
    pGroup->nReal = iChunk+1;
  }
  if( pGroup->zName && pGroup->aReal[iChunk].z==0 ){
    char *z;
    int n = pGroup->nName;
    pGroup->aReal[iChunk].z = z = sqlite3_malloc( n+4 );
    if( z==0 ){
      return SQLITE_NOMEM;
    }
    multiplexFilename(pGroup->zName, pGroup->nName, pGroup->flags, iChunk, z);
  }
  return SQLITE_OK;
}
................................................................................
    return 0;
  }
#endif

  *rc = multiplexSubFilename(pGroup, iChunk);
  if( (*rc)==SQLITE_OK && (pSubOpen = pGroup->aReal[iChunk].p)==0 ){
    int flags, bExists;
    createFlag = (pGroup->flags & SQLITE_OPEN_CREATE)!=0;
    flags = pGroup->flags;
    if( createFlag ){
      flags |= SQLITE_OPEN_CREATE;
    }else if( iChunk==0 ){
      /* Fall through */
    }else if( pGroup->aReal[iChunk].z==0 ){
      return 0;
................................................................................
  multiplexGroup *pGroup,    /* The multiplexor group */
  int iChunk,                /* Which chunk to open.  0==original file */
  int *rc                    /* Result code in and out */
){
  sqlite3_file *pSub;
  sqlite3_int64 sz = 0;


  pSub = multiplexSubOpen(pGroup, iChunk, rc, NULL, 0);
  if( pSub==0 ) return 0;
  *rc = pSub->pMethods->xFileSize(pSub, &sz);
  return sz;
}    

/*
................................................................................
    pGroup = sqlite3_malloc( sz );
    if( pGroup==0 ){
      rc = SQLITE_NOMEM;
    }
  }

  if( rc==SQLITE_OK ){

    /* assign pointers to extra space allocated */
    memset(pGroup, 0, sz);
    pMultiplexOpen->pGroup = pGroup;
    pGroup->bEnabled = -1;
    pGroup->bTruncate = sqlite3_uri_boolean(zName, "truncate", 
                                 (flags & SQLITE_OPEN_MAIN_DB)==0);
    pGroup->szChunk = sqlite3_uri_int64(zName, "chunksize",
                                        SQLITE_MULTIPLEX_CHUNK_SIZE);
    pGroup->szChunk = (pGroup->szChunk+0xffff)&~0xffff;
    if( zName ){
      char *p = (char *)&pGroup[1];
      pGroup->zName = p;
      memcpy(pGroup->zName, zName, nName+1);
      pGroup->nName = nName;
................................................................................
  rc = pOrigVfs->xDelete(pOrigVfs, zName, syncDir);
  if( rc==SQLITE_OK ){
    /* If the main chunk was deleted successfully, also delete any subsequent
    ** chunks - starting with the last (highest numbered). 
    */
    int nName = strlen(zName);
    char *z;
    z = sqlite3_malloc(nName + 4);
    if( z==0 ){
      rc = SQLITE_IOERR_NOMEM;
    }else{
      int iChunk = 0;
      int bExists;
      do{
        multiplexFilename(zName, nName, SQLITE_OPEN_MAIN_JOURNAL, ++iChunk, z);

  while( *z2 ){ z2++; }
  return 0x3fffffff & (int)(z2 - z);
}

/*
** Generate the file-name for chunk iChunk of the group with base name
** zBase. The file-name is written to buffer zOut before returning. Buffer
** zOut must be allocated by the caller so that it is at least (nBase+5)
** bytes in size, where nBase is the length of zBase, not including the
** nul-terminator.
**
** If iChunk is 0 (or 400 - the number for the first journal file chunk),
** the output is a copy of the input string. Otherwise, if 
** SQLITE_ENABLE_8_3_NAMES is not defined or the input buffer does not contain
** a "." character, then the output is a copy of the input string with the 
** three-digit zero-padded decimal representation if iChunk appended to it. 
** For example:
**
**   zBase="test.db", iChunk=4  ->  zOut="test.db004"
**
** Or, if SQLITE_ENABLE_8_3_NAMES is defined and the input buffer contains
** a "." character, then everything after the "." is replaced by the 
** three-digit representation of iChunk.
**
**   zBase="test.db", iChunk=4  ->  zOut="test.004"
**
** The output buffer string is terminated by 2 0x00 bytes. This makes it safe
** to pass to sqlite3_uri_parameter() and similar.
*/
static void multiplexFilename(
  const char *zBase,              /* Filename for chunk 0 */
  int nBase,                      /* Size of zBase in bytes (without \0) */
  int flags,                      /* Flags used to open file */
  int iChunk,                     /* Chunk to generate filename for */
  char *zOut                      /* Buffer to write generated name to */
){
  int n = nBase;
  memcpy(zOut, zBase, n+1);
  if( iChunk!=0 && iChunk!=SQLITE_MULTIPLEX_JOURNAL_8_3_OFFSET ){

#ifdef SQLITE_ENABLE_8_3_NAMES
    int i;
    for(i=n-1; i>0 && i>=n-4 && zOut[i]!='.'; i--){}
    if( i>=n-4 ) n = i+1;
    if( flags & SQLITE_OPEN_MAIN_JOURNAL ){
      /* The extensions on overflow files for main databases are 001, 002,
       ** 003 and so forth.  To avoid name collisions, add 400 to the 
       ** extensions of journal files so that they are 401, 402, 403, ....
       */
      iChunk += SQLITE_MULTIPLEX_JOURNAL_8_3_OFFSET;
    }
#endif
    sqlite3_snprintf(4,&zOut[n],"%03d",iChunk);
    n += 3;
  }

  assert( zOut[n]=='\0' );
  zOut[n+1] = '\0';
}

/* Compute the filename for the iChunk-th chunk
*/
static int multiplexSubFilename(multiplexGroup *pGroup, int iChunk){
  if( iChunk>=pGroup->nReal ){
    struct multiplexReal *p;
................................................................................
    memset(&p[pGroup->nReal], 0, sizeof(p[0])*(iChunk+1-pGroup->nReal));
    pGroup->aReal = p;
    pGroup->nReal = iChunk+1;
  }
  if( pGroup->zName && pGroup->aReal[iChunk].z==0 ){
    char *z;
    int n = pGroup->nName;
    pGroup->aReal[iChunk].z = z = sqlite3_malloc( n+5 );
    if( z==0 ){
      return SQLITE_NOMEM;
    }
    multiplexFilename(pGroup->zName, pGroup->nName, pGroup->flags, iChunk, z);
  }
  return SQLITE_OK;
}
................................................................................
    return 0;
  }
#endif

  *rc = multiplexSubFilename(pGroup, iChunk);
  if( (*rc)==SQLITE_OK && (pSubOpen = pGroup->aReal[iChunk].p)==0 ){
    int flags, bExists;

    flags = pGroup->flags;
    if( createFlag ){
      flags |= SQLITE_OPEN_CREATE;
    }else if( iChunk==0 ){
      /* Fall through */
    }else if( pGroup->aReal[iChunk].z==0 ){
      return 0;
................................................................................
  multiplexGroup *pGroup,    /* The multiplexor group */
  int iChunk,                /* Which chunk to open.  0==original file */
  int *rc                    /* Result code in and out */
){
  sqlite3_file *pSub;
  sqlite3_int64 sz = 0;

  if( *rc ) return 0;
  pSub = multiplexSubOpen(pGroup, iChunk, rc, NULL, 0);
  if( pSub==0 ) return 0;
  *rc = pSub->pMethods->xFileSize(pSub, &sz);
  return sz;
}    

/*
................................................................................
    pGroup = sqlite3_malloc( sz );
    if( pGroup==0 ){
      rc = SQLITE_NOMEM;
    }
  }

  if( rc==SQLITE_OK ){
    const char *zUri = (flags & SQLITE_OPEN_URI) ? zName : 0;
    /* assign pointers to extra space allocated */
    memset(pGroup, 0, sz);
    pMultiplexOpen->pGroup = pGroup;
    pGroup->bEnabled = -1;
    pGroup->bTruncate = sqlite3_uri_boolean(zUri, "truncate", 
                                   (flags & SQLITE_OPEN_MAIN_DB)==0);
    pGroup->szChunk = sqlite3_uri_int64(zUri, "chunksize",
                                        SQLITE_MULTIPLEX_CHUNK_SIZE);
    pGroup->szChunk = (pGroup->szChunk+0xffff)&~0xffff;
    if( zName ){
      char *p = (char *)&pGroup[1];
      pGroup->zName = p;
      memcpy(pGroup->zName, zName, nName+1);
      pGroup->nName = nName;
................................................................................
  rc = pOrigVfs->xDelete(pOrigVfs, zName, syncDir);
  if( rc==SQLITE_OK ){
    /* If the main chunk was deleted successfully, also delete any subsequent
    ** chunks - starting with the last (highest numbered). 
    */
    int nName = strlen(zName);
    char *z;
    z = sqlite3_malloc(nName + 5);
    if( z==0 ){
      rc = SQLITE_IOERR_NOMEM;
    }else{
      int iChunk = 0;
      int bExists;
      do{
        multiplexFilename(zName, nName, SQLITE_OPEN_MAIN_JOURNAL, ++iChunk, z);

*/
int sqlite3_quota_file(const char *zFilename){
  char *zFull;
  sqlite3_file *fd;
  int rc;
  int outFlags = 0;
  sqlite3_int64 iSize;
  fd = (sqlite3_file*)sqlite3_malloc(gQuota.sThisVfs.szOsFile +
                                     gQuota.sThisVfs.mxPathname+1);




  if( fd==0 ) return SQLITE_NOMEM;

  zFull = gQuota.sThisVfs.szOsFile + (char*)fd;
  rc = gQuota.pOrigVfs->xFullPathname(gQuota.pOrigVfs, zFilename,
                                      gQuota.sThisVfs.mxPathname+1, zFull);


  if( rc==SQLITE_OK ){

    rc = quotaOpen(&gQuota.sThisVfs, zFull, fd, 
                   SQLITE_OPEN_READONLY | SQLITE_OPEN_MAIN_DB, &outFlags);
  }
  if( rc==SQLITE_OK ){
    fd->pMethods->xFileSize(fd, &iSize);
    fd->pMethods->xClose(fd);
  }else if( rc==SQLITE_CANTOPEN ){
    quotaGroup *pGroup;
    quotaFile *pFile;
    quotaEnter();
................................................................................
    pGroup = quotaGroupFind(zFull);
    if( pGroup ){
      pFile = quotaFindFile(pGroup, zFull, 0);
      if( pFile ) quotaRemoveFile(pFile);
    }
    quotaLeave();
  }


  sqlite3_free(fd);
  return rc;
}

/*
** Open a potentially quotaed file for I/O.
*/

*/
int sqlite3_quota_file(const char *zFilename){
  char *zFull;
  sqlite3_file *fd;
  int rc;
  int outFlags = 0;
  sqlite3_int64 iSize;

  int nAlloc = gQuota.sThisVfs.szOsFile + gQuota.sThisVfs.mxPathname+2;

  /* Allocate space for a file-handle and the full path for file zFilename */
  fd = (sqlite3_file *)sqlite3_malloc(nAlloc);
  if( fd==0 ){
    rc = SQLITE_NOMEM;
  }else{
    zFull = &((char *)fd)[gQuota.sThisVfs.szOsFile];
    rc = gQuota.pOrigVfs->xFullPathname(gQuota.pOrigVfs, zFilename,
        gQuota.sThisVfs.mxPathname+1, zFull);
  }

  if( rc==SQLITE_OK ){
    zFull[strlen(zFull)+1] = '\0';
    rc = quotaOpen(&gQuota.sThisVfs, zFull, fd, 
                   SQLITE_OPEN_READONLY | SQLITE_OPEN_MAIN_DB, &outFlags);

    if( rc==SQLITE_OK ){
      fd->pMethods->xFileSize(fd, &iSize);
      fd->pMethods->xClose(fd);
    }else if( rc==SQLITE_CANTOPEN ){
      quotaGroup *pGroup;
      quotaFile *pFile;
      quotaEnter();
................................................................................
      pGroup = quotaGroupFind(zFull);
      if( pGroup ){
        pFile = quotaFindFile(pGroup, zFull, 0);
        if( pFile ) quotaRemoveFile(pFile);
      }
      quotaLeave();
    }
  }

  sqlite3_free(fd);
  return rc;
}

/*
** Open a potentially quotaed file for I/O.
*/

** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
** three characters, then shorten the suffix on z[] to be the last three
** characters of the original suffix.
**
** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
** do the suffix shortening regardless of URI parameter.
**
** Assume that zBaseFilename contains two \000 terminator bytes (so that
** it can be harmlessly passed into sqlite3_uri_parameter()) and copy both
** zero terminator bytes into the end of the revised name.
**
** Examples:
**
**     test.db-journal    =>   test.nal
**     test.db-wal        =>   test.wal
**     test.db-shm        =>   test.shm
**     test.db-mj7f3319fa =>   test.9fa
*/
void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
  assert( zBaseFilename[strlen(zBaseFilename)+1]==0 );
#if SQLITE_ENABLE_8_3_NAMES<2
  if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
#endif
  {
    int i, sz;
    sz = sqlite3Strlen30(z);
    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 5);
  }
}
#endif

** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
** three characters, then shorten the suffix on z[] to be the last three
** characters of the original suffix.
**
** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
** do the suffix shortening regardless of URI parameter.
**




** Examples:
**
**     test.db-journal    =>   test.nal
**     test.db-wal        =>   test.wal
**     test.db-shm        =>   test.shm
**     test.db-mj7f3319fa =>   test.9fa
*/
void sqlite3FileSuffix3(const char *zBaseFilename, char *z){

#if SQLITE_ENABLE_8_3_NAMES<2
  if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
#endif
  {
    int i, sz;
    sz = sqlite3Strlen30(z);
    for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
    if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
  }
}
#endif

/*
** Invoke this macro on memory cells just prior to changing the
** value of the cell.  This macro verifies that shallow copies are
** not misused.
*/
#ifdef SQLITE_DEBUG
# define memAboutToChange(P,M) sqlite3VdbeMemPrepareToChange(P,M)
#else
# define memAboutToChange(P,M)
#endif

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
................................................................................
*/
#ifdef SQLITE_TEST
int sqlite3_search_count = 0;
#endif

/*
** When this global variable is positive, it gets decremented once before
** each instruction in the VDBE.  When reaches zero, the u1.isInterrupted
** field of the sqlite3 structure is set in order to simulate and interrupt.
**
** This facility is used for testing purposes only.  It does not function
** in an ordinary build.
*/
#ifdef SQLITE_TEST
int sqlite3_interrupt_count = 0;
#endif
................................................................................
** string that the register itself controls.  In other words, it
** converts an MEM_Ephem string into an MEM_Dyn string.
*/
#define Deephemeralize(P) \
   if( ((P)->flags&MEM_Ephem)!=0 \
       && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}

/*
** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
** P if required.
*/
#define ExpandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)

/* Return true if the cursor was opened using the OP_OpenSorter opcode. */
#ifdef SQLITE_OMIT_MERGE_SORT
# define isSorter(x) 0
#else
# define isSorter(x) ((x)->pSorter!=0)
#endif

................................................................................
** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
** if we run out of memory.
*/
static VdbeCursor *allocateCursor(
  Vdbe *p,              /* The virtual machine */
  int iCur,             /* Index of the new VdbeCursor */
  int nField,           /* Number of fields in the table or index */
  int iDb,              /* When database the cursor belongs to, or -1 */
  int isBtreeCursor     /* True for B-Tree.  False for pseudo-table or vtab */
){
  /* Find the memory cell that will be used to store the blob of memory
  ** required for this VdbeCursor structure. It is convenient to use a 
  ** vdbe memory cell to manage the memory allocation required for a
  ** VdbeCursor structure for the following reasons:
  **
................................................................................
/*
** The CHECK_FOR_INTERRUPT macro defined here looks to see if the
** sqlite3_interrupt() routine has been called.  If it has been, then
** processing of the VDBE program is interrupted.
**
** This macro added to every instruction that does a jump in order to
** implement a loop.  This test used to be on every single instruction,
** but that meant we more testing that we needed.  By only testing the
** flag on jump instructions, we get a (small) speed improvement.
*/
#define CHECK_FOR_INTERRUPT \
   if( db->u1.isInterrupted ) goto abort_due_to_interrupt;


#ifndef NDEBUG
................................................................................
    */
    assert( pOp->opflags==sqlite3OpcodeProperty[pOp->opcode] );
    if( pOp->opflags & OPFLG_OUT2_PRERELEASE ){
      assert( pOp->p2>0 );
      assert( pOp->p2<=p->nMem );
      pOut = &aMem[pOp->p2];
      memAboutToChange(p, pOut);
      MemReleaseExt(pOut);
      pOut->flags = MEM_Int;
    }

    /* Sanity checking on other operands */
#ifdef SQLITE_DEBUG
    if( (pOp->opflags & OPFLG_IN1)!=0 ){
      assert( pOp->p1>0 );
................................................................................
  int cnt;
  cnt = pOp->p3-pOp->p2;
  assert( pOp->p3<=p->nMem );
  pOut->flags = MEM_Null;
  while( cnt>0 ){
    pOut++;
    memAboutToChange(p, pOut);
    MemReleaseExt(pOut);
    pOut->flags = MEM_Null;
    cnt--;
  }
  break;
}


................................................................................
  ** then there are not enough fields in the record to satisfy the
  ** request.  In this case, set the value NULL or to P4 if P4 is
  ** a pointer to a Mem object.
  */
  if( aOffset[p2] ){
    assert( rc==SQLITE_OK );
    if( zRec ){
      MemReleaseExt(pDest);
      sqlite3VdbeSerialGet((u8 *)&zRec[aOffset[p2]], aType[p2], pDest);
    }else{
      len = sqlite3VdbeSerialTypeLen(aType[p2]);
      sqlite3VdbeMemMove(&sMem, pDest);
      rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex, &sMem);
      if( rc!=SQLITE_OK ){
        goto op_column_out;

/*
** Invoke this macro on memory cells just prior to changing the
** value of the cell.  This macro verifies that shallow copies are
** not misused.
*/
#ifdef SQLITE_DEBUG
# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
#else
# define memAboutToChange(P,M)
#endif

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
................................................................................
*/
#ifdef SQLITE_TEST
int sqlite3_search_count = 0;
#endif

/*
** When this global variable is positive, it gets decremented once before
** each instruction in the VDBE.  When it reaches zero, the u1.isInterrupted
** field of the sqlite3 structure is set in order to simulate an interrupt.
**
** This facility is used for testing purposes only.  It does not function
** in an ordinary build.
*/
#ifdef SQLITE_TEST
int sqlite3_interrupt_count = 0;
#endif
................................................................................
** string that the register itself controls.  In other words, it
** converts an MEM_Ephem string into an MEM_Dyn string.
*/
#define Deephemeralize(P) \
   if( ((P)->flags&MEM_Ephem)!=0 \
       && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}







/* Return true if the cursor was opened using the OP_OpenSorter opcode. */
#ifdef SQLITE_OMIT_MERGE_SORT
# define isSorter(x) 0
#else
# define isSorter(x) ((x)->pSorter!=0)
#endif

................................................................................
** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
** if we run out of memory.
*/
static VdbeCursor *allocateCursor(
  Vdbe *p,              /* The virtual machine */
  int iCur,             /* Index of the new VdbeCursor */
  int nField,           /* Number of fields in the table or index */
  int iDb,              /* Database the cursor belongs to, or -1 */
  int isBtreeCursor     /* True for B-Tree.  False for pseudo-table or vtab */
){
  /* Find the memory cell that will be used to store the blob of memory
  ** required for this VdbeCursor structure. It is convenient to use a 
  ** vdbe memory cell to manage the memory allocation required for a
  ** VdbeCursor structure for the following reasons:
  **
................................................................................
/*
** The CHECK_FOR_INTERRUPT macro defined here looks to see if the
** sqlite3_interrupt() routine has been called.  If it has been, then
** processing of the VDBE program is interrupted.
**
** This macro added to every instruction that does a jump in order to
** implement a loop.  This test used to be on every single instruction,
** but that meant we more testing than we needed.  By only testing the
** flag on jump instructions, we get a (small) speed improvement.
*/
#define CHECK_FOR_INTERRUPT \
   if( db->u1.isInterrupted ) goto abort_due_to_interrupt;


#ifndef NDEBUG
................................................................................
    */
    assert( pOp->opflags==sqlite3OpcodeProperty[pOp->opcode] );
    if( pOp->opflags & OPFLG_OUT2_PRERELEASE ){
      assert( pOp->p2>0 );
      assert( pOp->p2<=p->nMem );
      pOut = &aMem[pOp->p2];
      memAboutToChange(p, pOut);
      VdbeMemRelease(pOut);
      pOut->flags = MEM_Int;
    }

    /* Sanity checking on other operands */
#ifdef SQLITE_DEBUG
    if( (pOp->opflags & OPFLG_IN1)!=0 ){
      assert( pOp->p1>0 );
................................................................................
  int cnt;
  cnt = pOp->p3-pOp->p2;
  assert( pOp->p3<=p->nMem );
  pOut->flags = MEM_Null;
  while( cnt>0 ){
    pOut++;
    memAboutToChange(p, pOut);
    VdbeMemRelease(pOut);
    pOut->flags = MEM_Null;
    cnt--;
  }
  break;
}


................................................................................
  ** then there are not enough fields in the record to satisfy the
  ** request.  In this case, set the value NULL or to P4 if P4 is
  ** a pointer to a Mem object.
  */
  if( aOffset[p2] ){
    assert( rc==SQLITE_OK );
    if( zRec ){
      VdbeMemRelease(pDest);
      sqlite3VdbeSerialGet((u8 *)&zRec[aOffset[p2]], aType[p2], pDest);
    }else{
      len = sqlite3VdbeSerialTypeLen(aType[p2]);
      sqlite3VdbeMemMove(&sMem, pDest);
      rc = sqlite3VdbeMemFromBtree(pCrsr, aOffset[p2], len, pC->isIndex, &sMem);
      if( rc!=SQLITE_OK ){
        goto op_column_out;

double sqlite3VdbeRealValue(Mem*);
void sqlite3VdbeIntegerAffinity(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemReleaseExternal(Mem *p);
#define MemReleaseExt(X)  \
  if((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame)) \
    sqlite3VdbeMemReleaseExternal(X);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
................................................................................
  void sqlite3VdbeLeave(Vdbe*);
#else
# define sqlite3VdbeEnter(X)
# define sqlite3VdbeLeave(X)
#endif

#ifdef SQLITE_DEBUG
void sqlite3VdbeMemPrepareToChange(Vdbe*,Mem*);
#endif

#ifndef SQLITE_OMIT_FOREIGN_KEY
int sqlite3VdbeCheckFk(Vdbe *, int);
#else
# define sqlite3VdbeCheckFk(p,i) 0
#endif
................................................................................
  void sqlite3VdbePrintSql(Vdbe*);
  void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
#endif
int sqlite3VdbeMemHandleBom(Mem *pMem);

#ifndef SQLITE_OMIT_INCRBLOB
  int sqlite3VdbeMemExpandBlob(Mem *);

#else
  #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK

#endif

#endif /* !defined(_VDBEINT_H_) */

double sqlite3VdbeRealValue(Mem*);
void sqlite3VdbeIntegerAffinity(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemReleaseExternal(Mem *p);
#define VdbeMemRelease(X)  \
  if((X)->flags&(MEM_Agg|MEM_Dyn|MEM_RowSet|MEM_Frame)) \
    sqlite3VdbeMemReleaseExternal(X);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
................................................................................
  void sqlite3VdbeLeave(Vdbe*);
#else
# define sqlite3VdbeEnter(X)
# define sqlite3VdbeLeave(X)
#endif

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

#ifndef SQLITE_OMIT_FOREIGN_KEY
int sqlite3VdbeCheckFk(Vdbe *, int);
#else
# define sqlite3VdbeCheckFk(p,i) 0
#endif
................................................................................
  void sqlite3VdbePrintSql(Vdbe*);
  void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
#endif
int sqlite3VdbeMemHandleBom(Mem *pMem);

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

#endif /* !defined(_VDBEINT_H_) */

  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
  sqlite3VdbeChangeP4(p, addr, zP4, p4type);
  return addr;
}

/*
** Add an OP_ParseSchema opcode.  This routine is broken out from
** sqlite3VdbeAddOp4() since it needs to also local all btrees.

**
** The zWhere string must have been obtained from sqlite3_malloc().
** This routine will take ownership of the allocated memory.
*/
void sqlite3VdbeAddParseSchemaOp(Vdbe *p, int iDb, char *zWhere){
  int j;
  int addr = sqlite3VdbeAddOp3(p, OP_ParseSchema, iDb, 0, 0);
................................................................................
}
#endif

/*
** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
**
** The prepared statements need to know in advance the complete set of
** attached databases that they will be using.  A mask of these databases
** is maintained in p->btreeMask and is used for locking and other purposes.

*/
void sqlite3VdbeUsesBtree(Vdbe *p, int i){
  assert( i>=0 && i<p->db->nDb && i<(int)sizeof(yDbMask)*8 );
  assert( i<(int)sizeof(p->btreeMask)*8 );
  p->btreeMask |= ((yDbMask)1)<<i;
  if( i!=1 && sqlite3BtreeSharable(p->db->aDb[i].pBt) ){
    p->lockMask |= ((yDbMask)1)<<i;

  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
  sqlite3VdbeChangeP4(p, addr, zP4, p4type);
  return addr;
}

/*
** Add an OP_ParseSchema opcode.  This routine is broken out from
** sqlite3VdbeAddOp4() since it needs to also needs to mark all btrees
** as having been used.
**
** The zWhere string must have been obtained from sqlite3_malloc().
** This routine will take ownership of the allocated memory.
*/
void sqlite3VdbeAddParseSchemaOp(Vdbe *p, int iDb, char *zWhere){
  int j;
  int addr = sqlite3VdbeAddOp3(p, OP_ParseSchema, iDb, 0, 0);
................................................................................
}
#endif

/*
** Declare to the Vdbe that the BTree object at db->aDb[i] is used.
**
** The prepared statements need to know in advance the complete set of
** attached databases that will be use.  A mask of these databases
** is maintained in p->btreeMask.  The p->lockMask value is the subset of
** p->btreeMask of databases that will require a lock.
*/
void sqlite3VdbeUsesBtree(Vdbe *p, int i){
  assert( i>=0 && i<p->db->nDb && i<(int)sizeof(yDbMask)*8 );
  assert( i<(int)sizeof(p->btreeMask)*8 );
  p->btreeMask |= ((yDbMask)1)<<i;
  if( i!=1 && sqlite3BtreeSharable(p->db->aDb[i].pBt) ){
    p->lockMask |= ((yDbMask)1)<<i;

** stores a single value in the VDBE.  Mem is an opaque structure visible
** only within the VDBE.  Interface routines refer to a Mem using the
** name sqlite_value
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
** P if required.
*/
#define expandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)

/*
** If pMem is an object with a valid string representation, this routine
** ensures the internal encoding for the string representation is
** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
**
** If pMem is not a string object, or the encoding of the string
** representation is already stored using the requested encoding, then this
................................................................................
**
** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
*/
int sqlite3VdbeMemMakeWriteable(Mem *pMem){
  int f;
  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
  assert( (pMem->flags&MEM_RowSet)==0 );
  expandBlob(pMem);
  f = pMem->flags;
  if( (f&(MEM_Str|MEM_Blob)) && pMem->z!=pMem->zMalloc ){
    if( sqlite3VdbeMemGrow(pMem, pMem->n + 2, 1) ){
      return SQLITE_NOMEM;
    }
    pMem->z[pMem->n] = 0;
    pMem->z[pMem->n+1] = 0;
................................................................................

/*
** Release any memory held by the Mem. This may leave the Mem in an
** inconsistent state, for example with (Mem.z==0) and
** (Mem.type==SQLITE_TEXT).
*/
void sqlite3VdbeMemRelease(Mem *p){
  MemReleaseExt(p);
  sqlite3DbFree(p->db, p->zMalloc);
  p->z = 0;
  p->zMalloc = 0;
  p->xDel = 0;
}

/*
................................................................................
** This routine prepares a memory cell for modication by breaking
** its link to a shallow copy and by marking any current shallow
** copies of this cell as invalid.
**
** This is used for testing and debugging only - to make sure shallow
** copies are not misused.
*/
void sqlite3VdbeMemPrepareToChange(Vdbe *pVdbe, Mem *pMem){
  int i;
  Mem *pX;
  for(i=1, pX=&pVdbe->aMem[1]; i<=pVdbe->nMem; i++, pX++){
    if( pX->pScopyFrom==pMem ){
      pX->flags |= MEM_Invalid;
      pX->pScopyFrom = 0;
    }
................................................................................
** Make an shallow copy of pFrom into pTo.  Prior contents of
** pTo are freed.  The pFrom->z field is not duplicated.  If
** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
** and flags gets srcType (either MEM_Ephem or MEM_Static).
*/
void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
  assert( (pFrom->flags & MEM_RowSet)==0 );
  MemReleaseExt(pTo);
  memcpy(pTo, pFrom, MEMCELLSIZE);
  pTo->xDel = 0;
  if( (pFrom->flags&MEM_Static)==0 ){
    pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
    assert( srcType==MEM_Ephem || srcType==MEM_Static );
    pTo->flags |= srcType;
  }
................................................................................
** Make a full copy of pFrom into pTo.  Prior contents of pTo are
** freed before the copy is made.
*/
int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
  int rc = SQLITE_OK;

  assert( (pFrom->flags & MEM_RowSet)==0 );
  MemReleaseExt(pTo);
  memcpy(pTo, pFrom, MEMCELLSIZE);
  pTo->flags &= ~MEM_Dyn;

  if( pTo->flags&(MEM_Str|MEM_Blob) ){
    if( 0==(pFrom->flags&MEM_Static) ){
      pTo->flags |= MEM_Ephem;
      rc = sqlite3VdbeMemMakeWriteable(pTo);
................................................................................
  assert( (pVal->flags & MEM_RowSet)==0 );

  if( pVal->flags&MEM_Null ){
    return 0;
  }
  assert( (MEM_Blob>>3) == MEM_Str );
  pVal->flags |= (pVal->flags & MEM_Blob)>>3;
  expandBlob(pVal);
  if( pVal->flags&MEM_Str ){
    sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
    if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
      assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
      if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
        return 0;
      }

** stores a single value in the VDBE.  Mem is an opaque structure visible
** only within the VDBE.  Interface routines refer to a Mem using the
** name sqlite_value
*/
#include "sqliteInt.h"
#include "vdbeInt.h"







/*
** If pMem is an object with a valid string representation, this routine
** ensures the internal encoding for the string representation is
** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
**
** If pMem is not a string object, or the encoding of the string
** representation is already stored using the requested encoding, then this
................................................................................
**
** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
*/
int sqlite3VdbeMemMakeWriteable(Mem *pMem){
  int f;
  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
  assert( (pMem->flags&MEM_RowSet)==0 );
  ExpandBlob(pMem);
  f = pMem->flags;
  if( (f&(MEM_Str|MEM_Blob)) && pMem->z!=pMem->zMalloc ){
    if( sqlite3VdbeMemGrow(pMem, pMem->n + 2, 1) ){
      return SQLITE_NOMEM;
    }
    pMem->z[pMem->n] = 0;
    pMem->z[pMem->n+1] = 0;
................................................................................

/*
** Release any memory held by the Mem. This may leave the Mem in an
** inconsistent state, for example with (Mem.z==0) and
** (Mem.type==SQLITE_TEXT).
*/
void sqlite3VdbeMemRelease(Mem *p){
  VdbeMemRelease(p);
  sqlite3DbFree(p->db, p->zMalloc);
  p->z = 0;
  p->zMalloc = 0;
  p->xDel = 0;
}

/*
................................................................................
** This routine prepares a memory cell for modication by breaking
** its link to a shallow copy and by marking any current shallow
** copies of this cell as invalid.
**
** This is used for testing and debugging only - to make sure shallow
** copies are not misused.
*/
void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
  int i;
  Mem *pX;
  for(i=1, pX=&pVdbe->aMem[1]; i<=pVdbe->nMem; i++, pX++){
    if( pX->pScopyFrom==pMem ){
      pX->flags |= MEM_Invalid;
      pX->pScopyFrom = 0;
    }
................................................................................
** Make an shallow copy of pFrom into pTo.  Prior contents of
** pTo are freed.  The pFrom->z field is not duplicated.  If
** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
** and flags gets srcType (either MEM_Ephem or MEM_Static).
*/
void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
  assert( (pFrom->flags & MEM_RowSet)==0 );
  VdbeMemRelease(pTo);
  memcpy(pTo, pFrom, MEMCELLSIZE);
  pTo->xDel = 0;
  if( (pFrom->flags&MEM_Static)==0 ){
    pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
    assert( srcType==MEM_Ephem || srcType==MEM_Static );
    pTo->flags |= srcType;
  }
................................................................................
** Make a full copy of pFrom into pTo.  Prior contents of pTo are
** freed before the copy is made.
*/
int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
  int rc = SQLITE_OK;

  assert( (pFrom->flags & MEM_RowSet)==0 );
  VdbeMemRelease(pTo);
  memcpy(pTo, pFrom, MEMCELLSIZE);
  pTo->flags &= ~MEM_Dyn;

  if( pTo->flags&(MEM_Str|MEM_Blob) ){
    if( 0==(pFrom->flags&MEM_Static) ){
      pTo->flags |= MEM_Ephem;
      rc = sqlite3VdbeMemMakeWriteable(pTo);
................................................................................
  assert( (pVal->flags & MEM_RowSet)==0 );

  if( pVal->flags&MEM_Null ){
    return 0;
  }
  assert( (MEM_Blob>>3) == MEM_Str );
  pVal->flags |= (pVal->flags & MEM_Blob)>>3;
  ExpandBlob(pVal);
  if( pVal->flags&MEM_Str ){
    sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
    if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
      assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
      if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
        return 0;
      }

    /* If the database file may grow as a result of this checkpoint, hint
    ** about the eventual size of the db file to the VFS layer. 
    */
    if( rc==SQLITE_OK ){
      i64 nReq = ((i64)mxPage * szPage);
      rc = sqlite3OsFileSize(pWal->pDbFd, &nSize);
      if( rc==SQLITE_OK && nSize<nReq ){
        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_SIZE_HINT, &nReq);
      }
    }

    /* Iterate through the contents of the WAL, copying data to the db file. */
    while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
      i64 iOffset;
      assert( walFramePgno(pWal, iFrame)==iDbpage );
................................................................................
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }
      rc = sqlite3WalCheckpoint(
          pWal, SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
      );
      if( rc==SQLITE_OK ){
        int bPersist = -1;

        sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist);

        if( bPersist!=1 ){
          /* Try to delete the WAL file if the checkpoint completed and
          ** fsyned (rc==SQLITE_OK) and if we are not in persistent-wal
          ** mode (!bPersist) */
          isDelete = 1;
        }else if( pWal->mxWalSize>=0 ){
          /* Try to truncate the WAL file to zero bytes if the checkpoint
................................................................................
        }
      }
    }

    walIndexClose(pWal, isDelete);
    sqlite3OsClose(pWal->pWalFd);
    if( isDelete ){

      sqlite3OsDelete(pWal->pVfs, pWal->zWalName, 0);

    }
    WALTRACE(("WAL%p: closed\n", pWal));
    sqlite3_free((void *)pWal->apWiData);
    sqlite3_free(pWal);
  }
  return rc;
}

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

    /* Iterate through the contents of the WAL, copying data to the db file. */
    while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
      i64 iOffset;
      assert( walFramePgno(pWal, iFrame)==iDbpage );
................................................................................
        pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
      }
      rc = sqlite3WalCheckpoint(
          pWal, SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
      );
      if( rc==SQLITE_OK ){
        int bPersist = -1;
        sqlite3OsFileControlHint(
            pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersist
        );
        if( bPersist!=1 ){
          /* Try to delete the WAL file if the checkpoint completed and
          ** fsyned (rc==SQLITE_OK) and if we are not in persistent-wal
          ** mode (!bPersist) */
          isDelete = 1;
        }else if( pWal->mxWalSize>=0 ){
          /* Try to truncate the WAL file to zero bytes if the checkpoint
................................................................................
        }
      }
    }

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

  set rc [catch {db backup} res]
  lappend rc $res
} {1 {wrong # args: should be "db backup ?DATABASE? FILENAME"}}

# Try to restore from an unreadable file.
#
if {$tcl_platform(platform)=="windows"} {
  do_test backup2-10 {
    forcedelete bu3.db
    file mkdir bu3.db
    set rc [catch {db restore temp bu3.db} res]
    lappend rc $res
  } {1 {cannot open source database: unable to open database file}}




}
if {$tcl_platform(platform)!="windows"} {
  do_test backup2-10 {
    forcedelete bu3.db
    file mkdir bu3.db
    set rc [catch {db restore temp bu3.db} res]
    lappend rc $res
  } {1 {cannot open source database: disk I/O error}}
}

# Try to restore from something that is not a database file.
#
do_test backup2-11 {
  set rc [catch {db restore temp bu2.db} res]
  lappend rc $res
} {1 {restore failed: file is encrypted or is not a database}}

  set rc [catch {db backup} res]
  lappend rc $res
} {1 {wrong # args: should be "db backup ?DATABASE? FILENAME"}}

# Try to restore from an unreadable file.
#
if {$tcl_platform(platform)=="windows"} {





  set msg {cannot open source database: unable to open database file}
} elseif {$tcl_platform(os)=="OpenBSD"} {
  set msg {restore failed: file is encrypted or is not a database}
} else {
  set msg {cannot open source database: disk I/O error}
}

do_test backup2-10 {
  forcedelete bu3.db
  file mkdir bu3.db
  set rc [catch {db restore temp bu3.db} res]
  lappend rc $res
} [list 1 $msg]


# Try to restore from something that is not a database file.
#
do_test backup2-11 {
  set rc [catch {db restore temp bu2.db} res]
  lappend rc $res
} {1 {restore failed: file is encrypted or is not a database}}

# 2012 January 12
#
# 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.
#
#***********************************************************************
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix corruptF

# Do not use a codec for tests in this file, as the database file is
# manipulated directly using tcl scripts (using the [hexio_write] command).
#
do_not_use_codec

proc str {i} { format %08d $i }

# Create a 6 page database containing a single table - t1. Table t1 
# consists of page 2 (the root page) and pages 5 and 6 (leaf pages). 
# Database pages 3 and 4 are on the free list.
#
proc create_test_db {} {
  catch { db close }
  forcedelete test.db
  sqlite3 db test.db
  db func str str
  execsql {
    PRAGMA auto_vacuum = 0;
    PRAGMA page_size = 1024;
    CREATE TABLE t1(x);         /* root page = 2 */
    CREATE TABLE t2(x);         /* root page = 3 */
    CREATE TABLE t3(x);         /* root page = 4 */

    INSERT INTO t1 VALUES(str(1));
    INSERT INTO t1 SELECT str(rowid+1) FROM t1;
    INSERT INTO t1 SELECT str(rowid+2) FROM t1;
    INSERT INTO t1 SELECT str(rowid+4) FROM t1;
    INSERT INTO t1 SELECT str(rowid+8) FROM t1;
    INSERT INTO t1 SELECT str(rowid+16) FROM t1;
    INSERT INTO t1 SELECT str(rowid+32) FROM t1;
    INSERT INTO t1 SELECT str(rowid+64) FROM t1;
    DROP TABLE t2;
    DROP TABLE t3;
  }
  db close
}

do_test 1.1 { create_test_db } {}

# Check the db is as we expect. 6 pages in total, with 3 and 4 on the free
# list. Page 3 is the free list trunk and page 4 is a leaf.
#
do_test 1.2 { file size test.db } [expr 6*1024]
do_test 1.3 { hexio_read test.db 32 4 } 00000003
do_test 1.4 { hexio_read test.db [expr 2*1024] 12 } 000000000000000100000004

# Change the free-list entry to page 6 and reopen the db file.
do_test 1.5 { 
  hexio_write test.db [expr 2*1024 + 8] 00000006 
  sqlite3 db test.db
} {}

# Now create a new table in the database file. The root of the new table
# is page 6, which is also the right-most leaf page in table t1.
#
do_execsql_test 1.6 { 
  CREATE TABLE t4(x);
  SELECT * FROM sqlite_master;
} {
  table t1 t1 2 {CREATE TABLE t1(x)} 
  table t4 t4 6 {CREATE TABLE t4(x)}
}

# At one point this was causing an assert to fail.
#
# This statement opens a cursor on table t1 and does a full table scan. As
# each row is visited, it is copied into table t4. There is no temporary
# table.
#
# When the t1 cursor reaches page 6 (which is both the right-most leaf of
# t1 and the root of t4), it continues to iterate through the keys within
# it (which at this point are keys that have been inserted into t4). And
# for each row visited, another row is inserted into page 6 - it being the
# root page of t4. Eventually, page 6 becomes full and the height of the
# b-tree for table t4 increased. From the point of view of the t1 cursor,
# this unexpectedly reduces the number of keys on page 6 in the middle of
# its iteration, which causes an assert() to fail.
#
db_save_and_close
if 1 {
for {set i 0} {$i < 128} {incr i} {
  db_restore_and_reopen
  do_test 1.7.$i { 
    set res [
      catchsql { INSERT INTO t4 SELECT x FROM t1 WHERE rowid>$i }
    ]
    if {$res == "0 {}" || $res == "1 {database disk image is malformed}"} {
      set res ""
    }
    set res
  } {}
}
}

do_test 2.1 { create_test_db } {}
do_test 2.2 { file size test.db } [expr 6*1024]
do_test 2.3 { hexio_read test.db 32 4 } 00000003
do_test 2.4 { hexio_read test.db [expr 2*1024] 12 } 000000000000000100000004

# Change the free-list entry to page 5 and reopen the db file.
do_test 2.5 { 
  hexio_write test.db [expr 2*1024 + 8] 00000005 
  sqlite3 db test.db
} {}

# Now create a new table in the database file. The root of the new table
# is page 5, which is also the right-most leaf page in table t1.
#
do_execsql_test 2.6 { 
  CREATE TABLE t4(x);
  SELECT * FROM sqlite_master;
} {
  table t1 t1 2 {CREATE TABLE t1(x)} 
  table t4 t4 5 {CREATE TABLE t4(x)}
}

db_save_and_close
for {set i 127} {$i >= 0} {incr i -1} {
  db_restore_and_reopen
  do_test 2.7.$i { 
    set res [
      catchsql { 
        INSERT INTO t4 SELECT x FROM t1 WHERE rowid<$i ORDER BY rowid DESC 
      }
    ]
    if {$res == "0 {}" || $res == "1 {database disk image is malformed}"} {
      set res ""
    }
    set res
  } {}
}

finish_test

  } db2
  execsql { SELECT * FROM abc } db
  expr [nPage db] + [nPage db2]
} {20}
do_test malloc5-6.3.2 {
  # Try to release 7700 bytes. This should release all the 
  # non-dirty pages held by db2.
  sqlite3_release_memory [expr 7*1100]
  list [nPage db] [nPage db2]
} {10 3}
do_test malloc5-6.3.3 {
  # Try to release another 1000 bytes. This should come fromt the db
  # cache, since all three pages held by db2 are either in-use or diry.
  sqlite3_release_memory 1000
  list [nPage db] [nPage db2]
} {9 3}
do_test malloc5-6.3.4 {
  # Now release 9900 more (about 9 pages worth). This should expunge
  # the rest of the db cache. But the db2 cache remains intact, because
  # SQLite tries to avoid calling sync().
  if {$::tcl_platform(wordSize)==8} {
    sqlite3_release_memory 10177
  } else {
    sqlite3_release_memory 9900
  }
  list [nPage db] [nPage db2]
} {0 3}
do_test malloc5-6.3.5 {
  # But if we are really insistent, SQLite will consent to call sync()

  } db2
  execsql { SELECT * FROM abc } db
  expr [nPage db] + [nPage db2]
} {20}
do_test malloc5-6.3.2 {
  # Try to release 7700 bytes. This should release all the 
  # non-dirty pages held by db2.
  sqlite3_release_memory [expr 7*1132]
  list [nPage db] [nPage db2]
} {10 3}
do_test malloc5-6.3.3 {
  # Try to release another 1000 bytes. This should come fromt the db
  # cache, since all three pages held by db2 are either in-use or diry.
  sqlite3_release_memory 1000
  list [nPage db] [nPage db2]
} {9 3}
do_test malloc5-6.3.4 {
  # Now release 9900 more (about 9 pages worth). This should expunge
  # the rest of the db cache. But the db2 cache remains intact, because
  # SQLite tries to avoid calling sync().
  if {$::tcl_platform(wordSize)==8} {
    sqlite3_release_memory 10500
  } else {
    sqlite3_release_memory 9900
  }
  list [nPage db] [nPage db2]
} {0 3}
do_test malloc5-6.3.5 {
  # But if we are really insistent, SQLite will consent to call sync()

#   multiplex-2.7.*: Disable/enable tests.
#

sqlite3_multiplex_initialize "" 1
multiplex_set db main 32768 16

forcedelete test.x



do_test multiplex-2.1.2 {
  sqlite3 db test.x
  execsql {
    PRAGMA page_size=1024;
    PRAGMA auto_vacuum=OFF;
    PRAGMA journal_mode=DELETE;
  }
................................................................................
do_test multiplex-2.4.1 {
  sqlite3_multiplex_shutdown
} {SQLITE_MISUSE}
do_test multiplex-2.4.2 {
  execsql { INSERT INTO t1 VALUES(3, randomblob(1100)) }
} {}
do_test multiplex-2.4.4 { file size [multiplex_name test.x 0] } {7168}
do_test multiplex-2.4.99 {
  db close






  sqlite3_multiplex_shutdown
} {SQLITE_OK}


do_test multiplex-2.5.1 {
  multiplex_delete test.x
  sqlite3_multiplex_initialize "" 1
  sqlite3 db test.x
  multiplex_set db main 4096 16
} {SQLITE_OK}

#   multiplex-2.7.*: Disable/enable tests.
#

sqlite3_multiplex_initialize "" 1
multiplex_set db main 32768 16

forcedelete test.x
foreach f [glob -nocomplain {test.x*[0-9][0-9][0-9]}] {
  forcedelete $f
}
do_test multiplex-2.1.2 {
  sqlite3 db test.x
  execsql {
    PRAGMA page_size=1024;
    PRAGMA auto_vacuum=OFF;
    PRAGMA journal_mode=DELETE;
  }
................................................................................
do_test multiplex-2.4.1 {
  sqlite3_multiplex_shutdown
} {SQLITE_MISUSE}
do_test multiplex-2.4.2 {
  execsql { INSERT INTO t1 VALUES(3, randomblob(1100)) }
} {}
do_test multiplex-2.4.4 { file size [multiplex_name test.x 0] } {7168}
do_test multiplex-2.4.5 {
  db close
  sqlite3 db test.x
  db eval vacuum
  db close
  glob test.x*
} {test.x}
do_test multiplex-2.4.99 {
  sqlite3_multiplex_shutdown
} {SQLITE_OK}


do_test multiplex-2.5.1 {
  multiplex_delete test.x
  sqlite3_multiplex_initialize "" 1
  sqlite3 db test.x
  multiplex_set db main 4096 16
} {SQLITE_OK}

  test_set $allquicktests -exclude *malloc* *ioerr* *fault*
]

test_suite "valgrind" -prefix "" -description {
  Run the "veryquick" test suite with a couple of multi-process tests (that
  fail under valgrind) omitted.
} -files [
  test_set $allquicktests -exclude *malloc* *ioerr* *fault*
] -initialize {
  set ::G(valgrind) 1
} -shutdown {
  unset -nocomplain ::G(valgrind)
}

test_suite "quick" -prefix "" -description {
................................................................................
  journal3.test 8_3_names.test

  pager1.test async4.test corrupt.test filefmt.test pager2.test
  corrupt5.test corruptA.test pageropt.test

  # Exclude stmt.test, which expects sub-journals to use temporary files.
  stmt.test



  # WAL mode is different.
  wal* tkt-2d1a5c67d.test backcompat.test
}]

ifcapable mem3 {
  test_suite "memsys3" -description {

  test_set $allquicktests -exclude *malloc* *ioerr* *fault*
]

test_suite "valgrind" -prefix "" -description {
  Run the "veryquick" test suite with a couple of multi-process tests (that
  fail under valgrind) omitted.
} -files [
  test_set $allquicktests -exclude *malloc* *ioerr* *fault* wal.test
] -initialize {
  set ::G(valgrind) 1
} -shutdown {
  unset -nocomplain ::G(valgrind)
}

test_suite "quick" -prefix "" -description {
................................................................................
  journal3.test 8_3_names.test

  pager1.test async4.test corrupt.test filefmt.test pager2.test
  corrupt5.test corruptA.test pageropt.test

  # Exclude stmt.test, which expects sub-journals to use temporary files.
  stmt.test

  zerodamage.test

  # WAL mode is different.
  wal* tkt-2d1a5c67d.test backcompat.test
}]

ifcapable mem3 {
  test_suite "memsys3" -description {

set testdir [file dirname $argv0]
source $testdir/tester.tcl

unset -nocomplain baseline
do_test shrink-1.1 {
  db eval {

    CREATE TABLE t1(x,y);
    INSERT INTO t1 VALUES(randomblob(1000000),1);
  }
  set ::baseline sqlite3_memory_used
  sqlite3_db_release_memory db
  expr {$::baseline > [sqlite3_memory_used]+500000}
} {1}

set testdir [file dirname $argv0]
source $testdir/tester.tcl

unset -nocomplain baseline
do_test shrink-1.1 {
  db eval {
    PRAGMA cache_size = 2000;
    CREATE TABLE t1(x,y);
    INSERT INTO t1 VALUES(randomblob(1000000),1);
  }
  set ::baseline sqlite3_memory_used
  sqlite3_db_release_memory db
  expr {$::baseline > [sqlite3_memory_used]+500000}
} {1}

source $testdir/tester.tcl

# Check the error messages generated by tclsqlite
#
if {[sqlite3 -has-codec]} {
  set r "sqlite_orig HANDLE FILENAME ?-key CODEC-KEY?"
} else {
  set r "sqlite_orig HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN? ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN?"
}
do_test tcl-1.1 {
  set v [catch {sqlite3 bogus} msg]
  regsub {really_sqlite3} $msg {sqlite3} msg
  lappend v $msg
} [list 1 "wrong # args: should be \"$r\""]
do_test tcl-1.2 {

source $testdir/tester.tcl

# Check the error messages generated by tclsqlite
#
if {[sqlite3 -has-codec]} {
  set r "sqlite_orig HANDLE FILENAME ?-key CODEC-KEY?"
} else {
  set r "sqlite_orig HANDLE FILENAME ?-vfs VFSNAME? ?-readonly BOOLEAN? ?-create BOOLEAN? ?-nomutex BOOLEAN? ?-fullmutex BOOLEAN? ?-uri BOOLEAN?"
}
do_test tcl-1.1 {
  set v [catch {sqlite3 bogus} msg]
  regsub {really_sqlite3} $msg {sqlite3} msg
  lappend v $msg
} [list 1 "wrong # args: should be \"$r\""]
do_test tcl-1.2 {

}

do_multiclient_test tn {
  do_test unixexcl-3.$tn.1 {
    code1 { db close; sqlite3 db file:test.db?psow=0 -vfs unix-excl -uri 1 }
    code2 { db2 close; sqlite3 db2 file:test.db?psow=0 -vfs unix-excl -uri 1 }
    sql1 {

      PRAGMA journal_mode = WAL;
      CREATE TABLE t1(a, b);
      INSERT INTO t1 VALUES(1, 2);
    }
  } {wal}

  if {$tn==1} {

}

do_multiclient_test tn {
  do_test unixexcl-3.$tn.1 {
    code1 { db close; sqlite3 db file:test.db?psow=0 -vfs unix-excl -uri 1 }
    code2 { db2 close; sqlite3 db2 file:test.db?psow=0 -vfs unix-excl -uri 1 }
    sql1 {
      PRAGMA auto_vacuum = 0;
      PRAGMA journal_mode = WAL;
      CREATE TABLE t1(a, b);
      INSERT INTO t1 VALUES(1, 2);
    }
  } {wal}

  if {$tn==1} {

}

# walcrash-2.*
#
for {set i 1} {$i < $REPEATS} {incr i} {
  forcedelete test.db test.db-wal
  do_test walcrash-2.$i.1 {
    crashsql -delay 4 -file test.db-wal -seed [incr seed] {
      PRAGMA journal_mode = WAL;
      CREATE TABLE t1(a PRIMARY KEY, b);
      INSERT INTO t1 VALUES(1, 2);
      INSERT INTO t1 VALUES(3, 4);
      INSERT INTO t1 VALUES(5, 9);
    }
  } {1 {child process exited abnormally}}
................................................................................
# walcrash-4.*
#
for {set i 1} {$i < $REPEATS} {incr i} {
  forcedelete test.db test.db-wal
  forcedelete test2.db test2.db-wal

  do_test walcrash-4.$i.1 {
    crashsql -delay 3 -file test.db-wal -seed [incr seed] -blocksize 4096 {
      PRAGMA journal_mode = WAL;
      PRAGMA page_size = 1024;
      CREATE TABLE t1(a PRIMARY KEY, b);
      INSERT INTO t1 VALUES(1, 2);
      INSERT INTO t1 VALUES(3, 4);
    }
  } {1 {child process exited abnormally}}
................................................................................
# walcrash-5.*
#
for {set i 1} {$i < $REPEATS} {incr i} {
  forcedelete test.db test.db-wal
  forcedelete test2.db test2.db-wal

  do_test walcrash-5.$i.1 {
    crashsql -delay 11 -file test.db-wal -seed [incr seed] -blocksize 4096 {
      PRAGMA journal_mode = WAL;
      PRAGMA page_size = 1024;
      BEGIN;
        CREATE TABLE t1(x PRIMARY KEY);
        INSERT INTO t1 VALUES(randomblob(900));
        INSERT INTO t1 VALUES(randomblob(900));
        INSERT INTO t1 SELECT randomblob(900) FROM t1;           /* 4 */
................................................................................
# walcrash-6.*
#
for {set i 1} {$i < $REPEATS} {incr i} {
  forcedelete test.db test.db-wal
  forcedelete test2.db test2.db-wal

  do_test walcrash-6.$i.1 {
    crashsql -delay 12 -file test.db-wal -seed [incr seed] -blocksize 512 {
      PRAGMA journal_mode = WAL;
      PRAGMA page_size = 1024;
      BEGIN;
        CREATE TABLE t1(x PRIMARY KEY);
        INSERT INTO t1 VALUES(randomblob(900));
        INSERT INTO t1 VALUES(randomblob(900));
        INSERT INTO t1 SELECT randomblob(900) FROM t1;           /* 4 */
................................................................................
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 16 */
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 20 */
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 24 */
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 28 */
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 32 */

      PRAGMA wal_checkpoint;
      INSERT INTO t1 VALUES(randomblob(900));
      INSERT INTO t1 VALUES(randomblob(900));
      INSERT INTO t1 VALUES(randomblob(900));
    }
  } {1 {child process exited abnormally}}

  do_test walcrash-6.$i.2 {
    sqlite3 db test.db
    execsql { SELECT count(*)==34 OR count(*)==35 FROM t1 WHERE x != 1 }
  } {1}

}

# walcrash-2.*
#
for {set i 1} {$i < $REPEATS} {incr i} {
  forcedelete test.db test.db-wal
  do_test walcrash-2.$i.1 {
    crashsql -delay 5 -file test.db-wal -seed [incr seed] {
      PRAGMA journal_mode = WAL;
      CREATE TABLE t1(a PRIMARY KEY, b);
      INSERT INTO t1 VALUES(1, 2);
      INSERT INTO t1 VALUES(3, 4);
      INSERT INTO t1 VALUES(5, 9);
    }
  } {1 {child process exited abnormally}}
................................................................................
# walcrash-4.*
#
for {set i 1} {$i < $REPEATS} {incr i} {
  forcedelete test.db test.db-wal
  forcedelete test2.db test2.db-wal

  do_test walcrash-4.$i.1 {
    crashsql -delay 4 -file test.db-wal -seed [incr seed] -blocksize 4096 {
      PRAGMA journal_mode = WAL;
      PRAGMA page_size = 1024;
      CREATE TABLE t1(a PRIMARY KEY, b);
      INSERT INTO t1 VALUES(1, 2);
      INSERT INTO t1 VALUES(3, 4);
    }
  } {1 {child process exited abnormally}}
................................................................................
# walcrash-5.*
#
for {set i 1} {$i < $REPEATS} {incr i} {
  forcedelete test.db test.db-wal
  forcedelete test2.db test2.db-wal

  do_test walcrash-5.$i.1 {
    crashsql -delay 13 -file test.db-wal -seed [incr seed] -blocksize 4096 {
      PRAGMA journal_mode = WAL;
      PRAGMA page_size = 1024;
      BEGIN;
        CREATE TABLE t1(x PRIMARY KEY);
        INSERT INTO t1 VALUES(randomblob(900));
        INSERT INTO t1 VALUES(randomblob(900));
        INSERT INTO t1 SELECT randomblob(900) FROM t1;           /* 4 */
................................................................................
# walcrash-6.*
#
for {set i 1} {$i < $REPEATS} {incr i} {
  forcedelete test.db test.db-wal
  forcedelete test2.db test2.db-wal

  do_test walcrash-6.$i.1 {
    crashsql -delay 14 -file test.db-wal -seed [incr seed] -blocksize 512 {
      PRAGMA journal_mode = WAL;
      PRAGMA page_size = 1024;
      BEGIN;
        CREATE TABLE t1(x PRIMARY KEY);
        INSERT INTO t1 VALUES(randomblob(900));
        INSERT INTO t1 VALUES(randomblob(900));
        INSERT INTO t1 SELECT randomblob(900) FROM t1;           /* 4 */
................................................................................
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 16 */
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 20 */
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 24 */
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 28 */
      INSERT INTO t1 SELECT randomblob(900) FROM t1 LIMIT 4;   /* 32 */

      PRAGMA wal_checkpoint;
      INSERT INTO t1 VALUES(randomblob(9000));
      INSERT INTO t1 VALUES(randomblob(9000));
      INSERT INTO t1 VALUES(randomblob(9000));
    }
  } {1 {child process exited abnormally}}

  do_test walcrash-6.$i.2 {
    sqlite3 db test.db
    execsql { SELECT count(*)==34 OR count(*)==35 FROM t1 WHERE x != 1 }
  } {1}

    PRAGMA wal_checkpoint;
  }
  set {} {}
} -test {
  faultsim_test_result {0 {}}
}


#--------------------------------------------------------------------------
#
if {[permutation] != "inmemory_journal"} {
  faultsim_delete_and_reopen
  faultsim_save_and_close
  do_faultsim_test walfault-4 -prep {
    faultsim_restore_and_reopen
................................................................................
      PRAGMA journal_mode = WAL;
      CREATE TABLE t1(a PRIMARY KEY, b);
      INSERT INTO t1 VALUES('a', 'b');
      PRAGMA wal_checkpoint;
      SELECT * FROM t1;
    }
  } -test {


    faultsim_test_result {0 {wal 0 7 7 a b}}
    faultsim_integrity_check
  } 
}

#--------------------------------------------------------------------------
#
do_test walfault-5-pre-1 {
................................................................................
  faultsim_restore_and_reopen
} -body {
  db eval { 
    PRAGMA wal_checkpoint = full;
    INSERT INTO abc VALUES(randomblob(1500));
  }
} -test {
  faultsim_test_result {0 {0 10 10}}
  faultsim_integrity_check
  set nRow [db eval {SELECT count(*) FROM abc}]
  if {!(($nRow==2 && $testrc) || $nRow==3)} { error "Bad db content" }
}


finish_test

    PRAGMA wal_checkpoint;
  }
  set {} {}
} -test {
  faultsim_test_result {0 {}}
}


#--------------------------------------------------------------------------
#
if {[permutation] != "inmemory_journal"} {
  faultsim_delete_and_reopen
  faultsim_save_and_close
  do_faultsim_test walfault-4 -prep {
    faultsim_restore_and_reopen
................................................................................
      PRAGMA journal_mode = WAL;
      CREATE TABLE t1(a PRIMARY KEY, b);
      INSERT INTO t1 VALUES('a', 'b');
      PRAGMA wal_checkpoint;
      SELECT * FROM t1;
    }
  } -test {
    # Update: The following changed from {0 {wal 0 7 7 a b}} as a result
    # of PSOW being set by default.
    faultsim_test_result {0 {wal 0 5 5 a b}}
    faultsim_integrity_check
  } 
}

#--------------------------------------------------------------------------
#
do_test walfault-5-pre-1 {
................................................................................
  faultsim_restore_and_reopen
} -body {
  db eval { 
    PRAGMA wal_checkpoint = full;
    INSERT INTO abc VALUES(randomblob(1500));
  }
} -test {
  faultsim_test_result {0 {0 9 9}}
  faultsim_integrity_check
  set nRow [db eval {SELECT count(*) FROM abc}]
  if {!(($nRow==2 && $testrc) || $nRow==3)} { error "Bad db content" }
}
finish_test

finish_test

# The name of this file comes from the fact that we used to call the
# POWERSAFE_OVERWRITE property ZERO_DAMAGE.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix wal5






# POWERSAFE_OVERWRITE defaults to true
#
do_test zerodamage-1.0 {
  file_control_powersafe_overwrite db -1
} {0 1}

................................................................................
  db close
  sqlite3 db file:test.db?psow=FALSE -uri 1
  db eval {
     UPDATE t1 SET y=randomblob(50) WHERE x=124;
  }
  file size test.db-wal
} {8416}

# The name of this file comes from the fact that we used to call the
# POWERSAFE_OVERWRITE property ZERO_DAMAGE.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix wal5

ifcapable !vtab {
  finish_test
  return
}

# POWERSAFE_OVERWRITE defaults to true
#
do_test zerodamage-1.0 {
  file_control_powersafe_overwrite db -1
} {0 1}

................................................................................
  db close
  sqlite3 db file:test.db?psow=FALSE -uri 1
  db eval {
     UPDATE t1 SET y=randomblob(50) WHERE x=124;
  }
  file size test.db-wal
} {8416}

finish_test

void CompressTables(struct lemon *);
void ResortStates(struct lemon *);

/********** From the file "set.h" ****************************************/
void  SetSize(int);             /* All sets will be of size N */
char *SetNew(void);               /* A new set for element 0..N */
void  SetFree(char*);             /* Deallocate a set */

char *SetNew(void);               /* A new set for element 0..N */
int SetAdd(char*,int);            /* Add element to a set */
int SetUnion(char *,char *);    /* A <- A U B, thru element N */
#define SetFind(X,Y) (X[Y])       /* True if Y is in set X */

/********** From the file "struct.h" *************************************/
/*
** Principal data structures for the LEMON parser generator.
................................................................................
  /* First compute all lambdas */
  do{
    progress = 0;
    for(rp=lemp->rule; rp; rp=rp->next){
      if( rp->lhs->lambda ) continue;
      for(i=0; i<rp->nrhs; i++){
         struct symbol *sp = rp->rhs[i];

         if( sp->type!=TERMINAL || sp->lambda==LEMON_FALSE ) break;
      }
      if( i==rp->nrhs ){
        rp->lhs->lambda = LEMON_TRUE;
        progress = 1;
      }
    }
  }while( progress );
................................................................................
	}
        cfp->status = COMPLETE;
      }
    }
  }while( progress );
}

static int resolve_conflict(struct action *,struct action *, struct symbol *);

/* Compute the reduce actions, and resolve conflicts.
*/
void FindActions(struct lemon *lemp)
{
  int i,j;
  struct config *cfp;
................................................................................
    stp = lemp->sorted[i];
    /* assert( stp->ap ); */
    stp->ap = Action_sort(stp->ap);
    for(ap=stp->ap; ap && ap->next; ap=ap->next){
      for(nap=ap->next; nap && nap->sp==ap->sp; nap=nap->next){
         /* The two actions "ap" and "nap" have the same lookahead.
         ** Figure out which one should be used */
         lemp->nconflict += resolve_conflict(ap,nap,lemp->errsym);
      }
    }
  }

  /* Report an error for each rule that can never be reduced. */
  for(rp=lemp->rule; rp; rp=rp->next) rp->canReduce = LEMON_FALSE;
  for(i=0; i<lemp->nstate; i++){
................................................................................
**   use precedence to resolve the conflict.
**
** If either action is a SHIFT, then it must be apx.  This
** function won't work if apx->type==REDUCE and apy->type==SHIFT.
*/
static int resolve_conflict(
  struct action *apx,
  struct action *apy,
  struct symbol *errsym   /* The error symbol (if defined.  NULL otherwise) */
){
  struct symbol *spx, *spy;
  int errcnt = 0;
  assert( apx->sp==apy->sp );  /* Otherwise there would be no conflict */
  if( apx->type==SHIFT && apy->type==SHIFT ){
    apy->type = SSCONFLICT;
    errcnt++;
................................................................................
        psp->lhs = Symbol_new(x);
        psp->nrhs = 0;
        psp->lhsalias = 0;
        psp->state = WAITING_FOR_ARROW;
      }else if( x[0]=='{' ){
        if( psp->prevrule==0 ){
          ErrorMsg(psp->filename,psp->tokenlineno,
"There is no prior rule opon which to attach the code \
fragment which begins on this line.");
          psp->errorcnt++;
	}else if( psp->prevrule->code!=0 ){
          ErrorMsg(psp->filename,psp->tokenlineno,
"Code fragment beginning on this line is not the first \
to follow the previous rule.");
          psp->errorcnt++;

void CompressTables(struct lemon *);
void ResortStates(struct lemon *);

/********** From the file "set.h" ****************************************/
void  SetSize(int);             /* All sets will be of size N */
char *SetNew(void);               /* A new set for element 0..N */
void  SetFree(char*);             /* Deallocate a set */


int SetAdd(char*,int);            /* Add element to a set */
int SetUnion(char *,char *);    /* A <- A U B, thru element N */
#define SetFind(X,Y) (X[Y])       /* True if Y is in set X */

/********** From the file "struct.h" *************************************/
/*
** Principal data structures for the LEMON parser generator.
................................................................................
  /* First compute all lambdas */
  do{
    progress = 0;
    for(rp=lemp->rule; rp; rp=rp->next){
      if( rp->lhs->lambda ) continue;
      for(i=0; i<rp->nrhs; i++){
        struct symbol *sp = rp->rhs[i];
        assert( sp->type==NONTERMINAL || sp->lambda==LEMON_FALSE );
        if( sp->lambda==LEMON_FALSE ) break;
      }
      if( i==rp->nrhs ){
        rp->lhs->lambda = LEMON_TRUE;
        progress = 1;
      }
    }
  }while( progress );
................................................................................
	}
        cfp->status = COMPLETE;
      }
    }
  }while( progress );
}

static int resolve_conflict(struct action *,struct action *);

/* Compute the reduce actions, and resolve conflicts.
*/
void FindActions(struct lemon *lemp)
{
  int i,j;
  struct config *cfp;
................................................................................
    stp = lemp->sorted[i];
    /* assert( stp->ap ); */
    stp->ap = Action_sort(stp->ap);
    for(ap=stp->ap; ap && ap->next; ap=ap->next){
      for(nap=ap->next; nap && nap->sp==ap->sp; nap=nap->next){
         /* The two actions "ap" and "nap" have the same lookahead.
         ** Figure out which one should be used */
         lemp->nconflict += resolve_conflict(ap,nap);
      }
    }
  }

  /* Report an error for each rule that can never be reduced. */
  for(rp=lemp->rule; rp; rp=rp->next) rp->canReduce = LEMON_FALSE;
  for(i=0; i<lemp->nstate; i++){
................................................................................
**   use precedence to resolve the conflict.
**
** If either action is a SHIFT, then it must be apx.  This
** function won't work if apx->type==REDUCE and apy->type==SHIFT.
*/
static int resolve_conflict(
  struct action *apx,
  struct action *apy

){
  struct symbol *spx, *spy;
  int errcnt = 0;
  assert( apx->sp==apy->sp );  /* Otherwise there would be no conflict */
  if( apx->type==SHIFT && apy->type==SHIFT ){
    apy->type = SSCONFLICT;
    errcnt++;
................................................................................
        psp->lhs = Symbol_new(x);
        psp->nrhs = 0;
        psp->lhsalias = 0;
        psp->state = WAITING_FOR_ARROW;
      }else if( x[0]=='{' ){
        if( psp->prevrule==0 ){
          ErrorMsg(psp->filename,psp->tokenlineno,
"There is no prior rule upon which to attach the code \
fragment which begins on this line.");
          psp->errorcnt++;
	}else if( psp->prevrule->code!=0 ){
          ErrorMsg(psp->filename,psp->tokenlineno,
"Code fragment beginning on this line is not the first \
to follow the previous rule.");
          psp->errorcnt++;