** 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.
**
*************************************************************************
** $Id: btree.c,v 1.268 2005/09/16 11:32:18 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
  u8 *pPtrmap;    /* The pointer map page */
  Pgno iPtrmap;   /* The pointer map page number */
  int offset;     /* Offset in pointer map page */
  int rc;

  assert( pBt->autoVacuum );
  if( key==0 ){
    return SQLITE_CORRUPT;
  }
  iPtrmap = PTRMAP_PAGENO(pBt->usableSize, key);
  rc = sqlite3pager_get(pBt->pPager, iPtrmap, (void **)&pPtrmap);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  offset = PTRMAP_PTROFFSET(pBt->usableSize, key);
................................................................................
  }

  offset = PTRMAP_PTROFFSET(pBt->usableSize, key);
  if( pEType ) *pEType = pPtrmap[offset];
  if( pPgno ) *pPgno = get4byte(&pPtrmap[offset+1]);

  sqlite3pager_unref(pPtrmap);
  if( *pEType<1 || *pEType>5 ) return SQLITE_CORRUPT;
  return SQLITE_OK;
}

#endif /* SQLITE_OMIT_AUTOVACUUM */

/*
** Given a btree page and a cell index (0 means the first cell on
................................................................................
  pBt = pPage->pBt;
  assert( pBt!=0 );
  assert( pParent==0 || pParent->pBt==pBt );
  assert( pPage->pgno==sqlite3pager_pagenumber(pPage->aData) );
  assert( pPage->aData == &((unsigned char*)pPage)[-pBt->pageSize] );
  if( pPage->pParent!=pParent && (pPage->pParent!=0 || pPage->isInit) ){
    /* The parent page should never change unless the file is corrupt */
    return SQLITE_CORRUPT; /* bkpt-CORRUPT */
  }
  if( pPage->isInit ) return SQLITE_OK;
  if( pPage->pParent==0 && pParent!=0 ){
    pPage->pParent = pParent;
    sqlite3pager_ref(pParent->aData);
  }
  hdr = pPage->hdrOffset;
................................................................................
  pPage->idxShift = 0;
  usableSize = pBt->usableSize;
  pPage->cellOffset = cellOffset = hdr + 12 - 4*pPage->leaf;
  top = get2byte(&data[hdr+5]);
  pPage->nCell = get2byte(&data[hdr+3]);
  if( pPage->nCell>MX_CELL(pBt) ){
    /* To many cells for a single page.  The page must be corrupt */
    return SQLITE_CORRUPT; /* bkpt-CORRUPT */
  }
  if( pPage->nCell==0 && pParent!=0 && pParent->pgno!=1 ){
    /* All pages must have at least one cell, except for root pages */
    return SQLITE_CORRUPT; /* bkpt-CORRUPT */
  }

  /* Compute the total free space on the page */
  pc = get2byte(&data[hdr+1]);
  nFree = data[hdr+7] + top - (cellOffset + 2*pPage->nCell);
  while( pc>0 ){
    int next, size;
    if( pc>usableSize-4 ){
      /* Free block is off the page */
      return SQLITE_CORRUPT;  /* bkpt-CORRUPT */
    }
    next = get2byte(&data[pc]);
    size = get2byte(&data[pc+2]);
    if( next>0 && next<=pc+size+3 ){
      /* Free blocks must be in accending order */
      return SQLITE_CORRUPT;  /* bkpt-CORRUPT */
    }
    nFree += size;
    pc = next;
  }
  pPage->nFree = nFree;
  if( nFree>=usableSize ){
    /* Free space cannot exceed total page size */
    return SQLITE_CORRUPT;  /* bkpt-CORRUPT */
  }

  pPage->isInit = 1;
  pageIntegrity(pPage);
  return SQLITE_OK;
}

................................................................................
  Btree *pBt,          /* The database file */
  Pgno pgno,           /* Number of the page to get */
  MemPage **ppPage,    /* Write the page pointer here */
  MemPage *pParent     /* Parent of the page */
){
  int rc;
  if( pgno==0 ){
    return SQLITE_CORRUPT;  /* bkpt-CORRUPT */
  }
  rc = getPage(pBt, pgno, ppPage);
  if( rc==SQLITE_OK && (*ppPage)->isInit==0 ){
    rc = initPage(*ppPage, pParent);
  }
  return rc;
}
................................................................................
** PTRMAP_OVERFLOW2: pPage is an overflow-page. The pointer points at the next
**                   overflow page in the list.
*/
static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
  if( eType==PTRMAP_OVERFLOW2 ){
    /* The pointer is always the first 4 bytes of the page in this case.  */
    if( get4byte(pPage->aData)!=iFrom ){
      return SQLITE_CORRUPT;
    }
    put4byte(pPage->aData, iTo);
  }else{
    int isInitOrig = pPage->isInit;
    int i;
    int nCell;

................................................................................
        }
      }
    }
  
    if( i==nCell ){
      if( eType!=PTRMAP_BTREE || 
          get4byte(&pPage->aData[pPage->hdrOffset+8])!=iFrom ){
        return SQLITE_CORRUPT;
      }
      put4byte(&pPage->aData[pPage->hdrOffset+8], iTo);
    }

    pPage->isInit = isInitOrig;
  }
  return SQLITE_OK;
................................................................................

#ifndef NDEBUG
  int nRef = *sqlite3pager_stats(pPager);
#endif

  assert( pBt->autoVacuum );
  if( PTRMAP_ISPAGE(pgsz, sqlite3pager_pagecount(pPager)) ){
    return SQLITE_CORRUPT;
  }

  /* Figure out how many free-pages are in the database. If there are no
  ** free pages, then auto-vacuum is a no-op.
  */
  nFreeList = get4byte(&pBt->pPage1->aData[36]);
  if( nFreeList==0 ){
................................................................................
    if( PTRMAP_ISPAGE(pgsz, iDbPage) || iDbPage==PENDING_BYTE_PAGE(pBt) ){
      continue;
    }

    rc = ptrmapGet(pBt, iDbPage, &eType, &iPtrPage);
    if( rc!=SQLITE_OK ) goto autovacuum_out;
    if( eType==PTRMAP_ROOTPAGE ){
      rc = SQLITE_CORRUPT;
      goto autovacuum_out;
    }

    /* If iDbPage is free, do not swap it.  */
    if( eType==PTRMAP_FREEPAGE ){
      continue;
    }
................................................................................
        offset -= ovflSize;
      }
      sqlite3pager_unref(aPayload);
    }
  }

  if( amt>0 ){
    return SQLITE_CORRUPT; /* bkpt-CORRUPT */
  }
  return SQLITE_OK;
}

/*
** Read part of the key associated with cursor pCur.  Exactly
** "amt" bytes will be transfered into pBuf[].  The transfer
................................................................................
** wrong.  An error is returned if "offset+amt" is larger than
** the available payload.
*/
int sqlite3BtreeKey(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
  assert( pCur->isValid );
  assert( pCur->pPage!=0 );
  if( pCur->pPage->intKey ){
    return SQLITE_CORRUPT;
  }
  assert( pCur->pPage->intKey==0 );
  assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
  return getPayload(pCur, offset, amt, (unsigned char*)pBuf, 0);
}

/*
................................................................................
  pOldPage = pCur->pPage;
  pOldPage->idxShift = 0;
  releasePage(pOldPage);
  pCur->pPage = pNewPage;
  pCur->idx = 0;
  pCur->info.nSize = 0;
  if( pNewPage->nCell<1 ){
    return SQLITE_CORRUPT; /* bkpt-CORRUPT */
  }
  return SQLITE_OK;
}

/*
** Return true if the page is the virtual root of its table.
**
................................................................................
    int lwr, upr;
    Pgno chldPg;
    MemPage *pPage = pCur->pPage;
    int c = -1;  /* pRes return if table is empty must be -1 */
    lwr = 0;
    upr = pPage->nCell-1;
    if( !pPage->intKey && pKey==0 ){
      return SQLITE_CORRUPT;
    }
    pageIntegrity(pPage);
    while( lwr<=upr ){
      void *pCellKey;
      i64 nCellKey;
      pCur->idx = (lwr+upr)/2;
      pCur->info.nSize = 0;
................................................................................
        *pPgno = iTrunk;
        memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
        *ppPage = pTrunk;
        pTrunk = 0;
        TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
      }else if( k>pBt->usableSize/4 - 8 ){
        /* Value of k is out of range.  Database corruption */
        return SQLITE_CORRUPT; /* bkpt-CORRUPT */
#ifndef SQLITE_OMIT_AUTOVACUUM
      }else if( searchList && nearby==iTrunk ){
        /* The list is being searched and this trunk page is the page
        ** to allocate, regardless of whether it has leaves.
        */
        assert( *pPgno==iTrunk );
        *ppPage = pTrunk;
................................................................................
        }

        iPage = get4byte(&aData[8+closest*4]);
        if( !searchList || iPage==nearby ){
          *pPgno = iPage;
          if( *pPgno>sqlite3pager_pagecount(pBt->pPager) ){
            /* Free page off the end of the file */
            return SQLITE_CORRUPT; /* bkpt-CORRUPT */
          }
          TRACE(("ALLOCATE: %d was leaf %d of %d on trunk %d"
                 ": %d more free pages\n",
                 *pPgno, closest+1, k, pTrunk->pgno, n-1));
          if( closest<k-1 ){
            memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
          }
................................................................................
  if( info.iOverflow==0 ){
    return SQLITE_OK;  /* No overflow pages. Return without doing anything */
  }
  ovflPgno = get4byte(&pCell[info.iOverflow]);
  while( ovflPgno!=0 ){
    MemPage *pOvfl;
    if( ovflPgno>sqlite3pager_pagecount(pBt->pPager) ){
      return SQLITE_CORRUPT;
    }
    rc = getPage(pBt, ovflPgno, &pOvfl);
    if( rc ) return rc;
    ovflPgno = get4byte(pOvfl->aData);
    rc = freePage(pOvfl);
    sqlite3pager_unref(pOvfl->aData);
    if( rc ) return rc;
................................................................................
    int notUsed;
    unsigned char *tempCell = 0;
    assert( !pPage->leafData );
    getTempCursor(pCur, &leafCur);
    rc = sqlite3BtreeNext(&leafCur, &notUsed);
    if( rc!=SQLITE_OK ){
      if( rc!=SQLITE_NOMEM ){
        rc = SQLITE_CORRUPT;  /* bkpt-CORRUPT */
      }
    }
    if( rc==SQLITE_OK ){
      rc = sqlite3pager_write(leafCur.pPage->aData);
    }
    if( rc==SQLITE_OK ){
      TRACE(("DELETE: table=%d delete internal from %d replace from leaf %d\n",
................................................................................
){
  MemPage *pPage = 0;
  int rc;
  unsigned char *pCell;
  int i;

  if( pgno>sqlite3pager_pagecount(pBt->pPager) ){
    return SQLITE_CORRUPT;
  }

  rc = getAndInitPage(pBt, pgno, &pPage, pParent);
  if( rc ) goto cleardatabasepage_out;
  rc = sqlite3pager_write(pPage->aData);
  if( rc ) goto cleardatabasepage_out;
  for(i=0; i<pPage->nCell; i++){
................................................................................
    if( rc ) break;
    rc = sqlite3pager_overwrite(pBtTo->pPager, i, pPage);
    if( rc ) break;
    sqlite3pager_unref(pPage);
  }
  for(i=nPage+1; rc==SQLITE_OK && i<=nToPage; i++){
    void *pPage;

    rc = sqlite3pager_get(pBtTo->pPager, i, &pPage);
    if( rc ) break;
    rc = sqlite3pager_write(pPage);
    sqlite3pager_unref(pPage);
    sqlite3pager_dont_write(pBtTo->pPager, i);
  }
  if( !rc && nPage<nToPage ){

** 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.
**
*************************************************************************
** $Id: btree.c,v 1.269 2005/09/17 15:20:27 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
  u8 *pPtrmap;    /* The pointer map page */
  Pgno iPtrmap;   /* The pointer map page number */
  int offset;     /* Offset in pointer map page */
  int rc;

  assert( pBt->autoVacuum );
  if( key==0 ){
    return SQLITE_CORRUPT_BKPT;
  }
  iPtrmap = PTRMAP_PAGENO(pBt->usableSize, key);
  rc = sqlite3pager_get(pBt->pPager, iPtrmap, (void **)&pPtrmap);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  offset = PTRMAP_PTROFFSET(pBt->usableSize, key);
................................................................................
  }

  offset = PTRMAP_PTROFFSET(pBt->usableSize, key);
  if( pEType ) *pEType = pPtrmap[offset];
  if( pPgno ) *pPgno = get4byte(&pPtrmap[offset+1]);

  sqlite3pager_unref(pPtrmap);
  if( *pEType<1 || *pEType>5 ) return SQLITE_CORRUPT_BKPT;
  return SQLITE_OK;
}

#endif /* SQLITE_OMIT_AUTOVACUUM */

/*
** Given a btree page and a cell index (0 means the first cell on
................................................................................
  pBt = pPage->pBt;
  assert( pBt!=0 );
  assert( pParent==0 || pParent->pBt==pBt );
  assert( pPage->pgno==sqlite3pager_pagenumber(pPage->aData) );
  assert( pPage->aData == &((unsigned char*)pPage)[-pBt->pageSize] );
  if( pPage->pParent!=pParent && (pPage->pParent!=0 || pPage->isInit) ){
    /* The parent page should never change unless the file is corrupt */
    return SQLITE_CORRUPT_BKPT;
  }
  if( pPage->isInit ) return SQLITE_OK;
  if( pPage->pParent==0 && pParent!=0 ){
    pPage->pParent = pParent;
    sqlite3pager_ref(pParent->aData);
  }
  hdr = pPage->hdrOffset;
................................................................................
  pPage->idxShift = 0;
  usableSize = pBt->usableSize;
  pPage->cellOffset = cellOffset = hdr + 12 - 4*pPage->leaf;
  top = get2byte(&data[hdr+5]);
  pPage->nCell = get2byte(&data[hdr+3]);
  if( pPage->nCell>MX_CELL(pBt) ){
    /* To many cells for a single page.  The page must be corrupt */
    return SQLITE_CORRUPT_BKPT;
  }
  if( pPage->nCell==0 && pParent!=0 && pParent->pgno!=1 ){
    /* All pages must have at least one cell, except for root pages */
    return SQLITE_CORRUPT_BKPT;
  }

  /* Compute the total free space on the page */
  pc = get2byte(&data[hdr+1]);
  nFree = data[hdr+7] + top - (cellOffset + 2*pPage->nCell);
  while( pc>0 ){
    int next, size;
    if( pc>usableSize-4 ){
      /* Free block is off the page */
      return SQLITE_CORRUPT_BKPT; 
    }
    next = get2byte(&data[pc]);
    size = get2byte(&data[pc+2]);
    if( next>0 && next<=pc+size+3 ){
      /* Free blocks must be in accending order */
      return SQLITE_CORRUPT_BKPT; 
    }
    nFree += size;
    pc = next;
  }
  pPage->nFree = nFree;
  if( nFree>=usableSize ){
    /* Free space cannot exceed total page size */
    return SQLITE_CORRUPT_BKPT; 
  }

  pPage->isInit = 1;
  pageIntegrity(pPage);
  return SQLITE_OK;
}

................................................................................
  Btree *pBt,          /* The database file */
  Pgno pgno,           /* Number of the page to get */
  MemPage **ppPage,    /* Write the page pointer here */
  MemPage *pParent     /* Parent of the page */
){
  int rc;
  if( pgno==0 ){
    return SQLITE_CORRUPT_BKPT; 
  }
  rc = getPage(pBt, pgno, ppPage);
  if( rc==SQLITE_OK && (*ppPage)->isInit==0 ){
    rc = initPage(*ppPage, pParent);
  }
  return rc;
}
................................................................................
** PTRMAP_OVERFLOW2: pPage is an overflow-page. The pointer points at the next
**                   overflow page in the list.
*/
static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
  if( eType==PTRMAP_OVERFLOW2 ){
    /* The pointer is always the first 4 bytes of the page in this case.  */
    if( get4byte(pPage->aData)!=iFrom ){
      return SQLITE_CORRUPT_BKPT;
    }
    put4byte(pPage->aData, iTo);
  }else{
    int isInitOrig = pPage->isInit;
    int i;
    int nCell;

................................................................................
        }
      }
    }
  
    if( i==nCell ){
      if( eType!=PTRMAP_BTREE || 
          get4byte(&pPage->aData[pPage->hdrOffset+8])!=iFrom ){
        return SQLITE_CORRUPT_BKPT;
      }
      put4byte(&pPage->aData[pPage->hdrOffset+8], iTo);
    }

    pPage->isInit = isInitOrig;
  }
  return SQLITE_OK;
................................................................................

#ifndef NDEBUG
  int nRef = *sqlite3pager_stats(pPager);
#endif

  assert( pBt->autoVacuum );
  if( PTRMAP_ISPAGE(pgsz, sqlite3pager_pagecount(pPager)) ){
    return SQLITE_CORRUPT_BKPT;
  }

  /* Figure out how many free-pages are in the database. If there are no
  ** free pages, then auto-vacuum is a no-op.
  */
  nFreeList = get4byte(&pBt->pPage1->aData[36]);
  if( nFreeList==0 ){
................................................................................
    if( PTRMAP_ISPAGE(pgsz, iDbPage) || iDbPage==PENDING_BYTE_PAGE(pBt) ){
      continue;
    }

    rc = ptrmapGet(pBt, iDbPage, &eType, &iPtrPage);
    if( rc!=SQLITE_OK ) goto autovacuum_out;
    if( eType==PTRMAP_ROOTPAGE ){
      rc = SQLITE_CORRUPT_BKPT;
      goto autovacuum_out;
    }

    /* If iDbPage is free, do not swap it.  */
    if( eType==PTRMAP_FREEPAGE ){
      continue;
    }
................................................................................
        offset -= ovflSize;
      }
      sqlite3pager_unref(aPayload);
    }
  }

  if( amt>0 ){
    return SQLITE_CORRUPT_BKPT;
  }
  return SQLITE_OK;
}

/*
** Read part of the key associated with cursor pCur.  Exactly
** "amt" bytes will be transfered into pBuf[].  The transfer
................................................................................
** wrong.  An error is returned if "offset+amt" is larger than
** the available payload.
*/
int sqlite3BtreeKey(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
  assert( pCur->isValid );
  assert( pCur->pPage!=0 );
  if( pCur->pPage->intKey ){
    return SQLITE_CORRUPT_BKPT;
  }
  assert( pCur->pPage->intKey==0 );
  assert( pCur->idx>=0 && pCur->idx<pCur->pPage->nCell );
  return getPayload(pCur, offset, amt, (unsigned char*)pBuf, 0);
}

/*
................................................................................
  pOldPage = pCur->pPage;
  pOldPage->idxShift = 0;
  releasePage(pOldPage);
  pCur->pPage = pNewPage;
  pCur->idx = 0;
  pCur->info.nSize = 0;
  if( pNewPage->nCell<1 ){
    return SQLITE_CORRUPT_BKPT;
  }
  return SQLITE_OK;
}

/*
** Return true if the page is the virtual root of its table.
**
................................................................................
    int lwr, upr;
    Pgno chldPg;
    MemPage *pPage = pCur->pPage;
    int c = -1;  /* pRes return if table is empty must be -1 */
    lwr = 0;
    upr = pPage->nCell-1;
    if( !pPage->intKey && pKey==0 ){
      return SQLITE_CORRUPT_BKPT;
    }
    pageIntegrity(pPage);
    while( lwr<=upr ){
      void *pCellKey;
      i64 nCellKey;
      pCur->idx = (lwr+upr)/2;
      pCur->info.nSize = 0;
................................................................................
        *pPgno = iTrunk;
        memcpy(&pPage1->aData[32], &pTrunk->aData[0], 4);
        *ppPage = pTrunk;
        pTrunk = 0;
        TRACE(("ALLOCATE: %d trunk - %d free pages left\n", *pPgno, n-1));
      }else if( k>pBt->usableSize/4 - 8 ){
        /* Value of k is out of range.  Database corruption */
        return SQLITE_CORRUPT_BKPT;
#ifndef SQLITE_OMIT_AUTOVACUUM
      }else if( searchList && nearby==iTrunk ){
        /* The list is being searched and this trunk page is the page
        ** to allocate, regardless of whether it has leaves.
        */
        assert( *pPgno==iTrunk );
        *ppPage = pTrunk;
................................................................................
        }

        iPage = get4byte(&aData[8+closest*4]);
        if( !searchList || iPage==nearby ){
          *pPgno = iPage;
          if( *pPgno>sqlite3pager_pagecount(pBt->pPager) ){
            /* Free page off the end of the file */
            return SQLITE_CORRUPT_BKPT;
          }
          TRACE(("ALLOCATE: %d was leaf %d of %d on trunk %d"
                 ": %d more free pages\n",
                 *pPgno, closest+1, k, pTrunk->pgno, n-1));
          if( closest<k-1 ){
            memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
          }
................................................................................
  if( info.iOverflow==0 ){
    return SQLITE_OK;  /* No overflow pages. Return without doing anything */
  }
  ovflPgno = get4byte(&pCell[info.iOverflow]);
  while( ovflPgno!=0 ){
    MemPage *pOvfl;
    if( ovflPgno>sqlite3pager_pagecount(pBt->pPager) ){
      return SQLITE_CORRUPT_BKPT;
    }
    rc = getPage(pBt, ovflPgno, &pOvfl);
    if( rc ) return rc;
    ovflPgno = get4byte(pOvfl->aData);
    rc = freePage(pOvfl);
    sqlite3pager_unref(pOvfl->aData);
    if( rc ) return rc;
................................................................................
    int notUsed;
    unsigned char *tempCell = 0;
    assert( !pPage->leafData );
    getTempCursor(pCur, &leafCur);
    rc = sqlite3BtreeNext(&leafCur, &notUsed);
    if( rc!=SQLITE_OK ){
      if( rc!=SQLITE_NOMEM ){
        rc = SQLITE_CORRUPT_BKPT; 
      }
    }
    if( rc==SQLITE_OK ){
      rc = sqlite3pager_write(leafCur.pPage->aData);
    }
    if( rc==SQLITE_OK ){
      TRACE(("DELETE: table=%d delete internal from %d replace from leaf %d\n",
................................................................................
){
  MemPage *pPage = 0;
  int rc;
  unsigned char *pCell;
  int i;

  if( pgno>sqlite3pager_pagecount(pBt->pPager) ){
    return SQLITE_CORRUPT_BKPT;
  }

  rc = getAndInitPage(pBt, pgno, &pPage, pParent);
  if( rc ) goto cleardatabasepage_out;
  rc = sqlite3pager_write(pPage->aData);
  if( rc ) goto cleardatabasepage_out;
  for(i=0; i<pPage->nCell; i++){
................................................................................
    if( rc ) break;
    rc = sqlite3pager_overwrite(pBtTo->pPager, i, pPage);
    if( rc ) break;
    sqlite3pager_unref(pPage);
  }
  for(i=nPage+1; rc==SQLITE_OK && i<=nToPage; i++){
    void *pPage;
    if( i==iSkip ) continue;
    rc = sqlite3pager_get(pBtTo->pPager, i, &pPage);
    if( rc ) break;
    rc = sqlite3pager_write(pPage);
    sqlite3pager_unref(pPage);
    sqlite3pager_dont_write(pBtTo->pPager, i);
  }
  if( !rc && nPage<nToPage ){

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.301 2005/09/07 21:22:46 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and
................................................................................
** by the next COMMIT or ROLLBACK.
**
******* THIS IS AN EXPERIMENTAL API AND IS SUBJECT TO CHANGE ******
*/
int sqlite3_get_autocommit(sqlite3 *db){
  return db->autoCommit;
}

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.302 2005/09/17 15:20:27 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and
................................................................................
** by the next COMMIT or ROLLBACK.
**
******* THIS IS AN EXPERIMENTAL API AND IS SUBJECT TO CHANGE ******
*/
int sqlite3_get_autocommit(sqlite3 *db){
  return db->autoCommit;
}

#ifdef SQLITE_DEBUG
/*
** The following routine is subtituted for constant SQLITE_CORRUPT in
** debugging builds.  This provides a way to set a breakpoint for when
** corruption is first detected.
*/
int sqlite3Corrupt(void){
  return SQLITE_CORRUPT;
}
#endif

** The default location of PENDING_BYTE is the first byte past the
** 1GB boundary.
**
*/
#ifndef SQLITE_TEST
#define PENDING_BYTE      0x40000000  /* First byte past the 1GB boundary */
#else
/* Defined in test2.c (pager tests) */
extern unsigned int sqlite3_pending_byte;
#define PENDING_BYTE sqlite3_pending_byte
#endif

#define RESERVED_BYTE     (PENDING_BYTE+1)
#define SHARED_FIRST      (PENDING_BYTE+2)
#define SHARED_SIZE       510

** The default location of PENDING_BYTE is the first byte past the
** 1GB boundary.
**
*/
#ifndef SQLITE_TEST
#define PENDING_BYTE      0x40000000  /* First byte past the 1GB boundary */
#else

extern unsigned int sqlite3_pending_byte;
#define PENDING_BYTE sqlite3_pending_byte
#endif

#define RESERVED_BYTE     (PENDING_BYTE+1)
#define SHARED_FIRST      (PENDING_BYTE+2)
#define SHARED_SIZE       510

/*
 * When testing, this global variable stores the location of the
 * pending-byte in the database file.
 */
#ifdef SQLITE_TEST
unsigned int sqlite3_pending_byte = 0x0010000;
#endif

int sqlite3_os_trace = 0;
#ifdef SQLITE_DEBUG
static int last_page = 0;
#define SEEK(X)           last_page=(X)
#define TRACE1(X)         if( sqlite3_os_trace ) sqlite3DebugPrintf(X)

/*
 * When testing, this global variable stores the location of the
 * pending-byte in the database file.
 */
#ifdef SQLITE_TEST
unsigned int sqlite3_pending_byte = 0x40000000;
#endif

int sqlite3_os_trace = 0;
#ifdef SQLITE_DEBUG
static int last_page = 0;
#define SEEK(X)           last_page=(X)
#define TRACE1(X)         if( sqlite3_os_trace ) sqlite3DebugPrintf(X)

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.214 2005/09/16 17:16:53 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>
................................................................................
  }

  pPager->journalOff = szJ;
  
end_stmt_playback:
  if( rc!=SQLITE_OK ){
    pPager->errMask |= PAGER_ERR_CORRUPT;
    rc = SQLITE_CORRUPT;  /* bkpt-CORRUPT */
  }else{
    pPager->journalOff = szJ;
    /* pager_reload_cache(pPager); */
  }
  return rc;
}

................................................................................
  PgHdr *pPg;
  int rc;

  /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
  ** number greater than this, or zero, is requested.
  */
  if( pgno>PAGER_MAX_PGNO || pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
    return SQLITE_CORRUPT;
  }

  /* Make sure we have not hit any critical errors.
  */ 
  assert( pPager!=0 );
  *ppPage = 0;
  if( pPager->errMask & ~(PAGER_ERR_FULL) ){
................................................................................
    if( rc==SQLITE_OK ){
      rc = rc2;
    }
  }else{
    rc = pager_playback(pPager);
  }
  if( rc!=SQLITE_OK ){
    rc = SQLITE_CORRUPT;  /* bkpt-CORRUPT */
    pPager->errMask |= PAGER_ERR_CORRUPT;
  }
  pPager->dbSize = -1;
  return rc;
}

/*

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.215 2005/09/17 15:20:27 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>
................................................................................
  }

  pPager->journalOff = szJ;
  
end_stmt_playback:
  if( rc!=SQLITE_OK ){
    pPager->errMask |= PAGER_ERR_CORRUPT;
    rc = SQLITE_CORRUPT;
  }else{
    pPager->journalOff = szJ;
    /* pager_reload_cache(pPager); */
  }
  return rc;
}

................................................................................
  PgHdr *pPg;
  int rc;

  /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
  ** number greater than this, or zero, is requested.
  */
  if( pgno>PAGER_MAX_PGNO || pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
    return SQLITE_CORRUPT_BKPT;
  }

  /* Make sure we have not hit any critical errors.
  */ 
  assert( pPager!=0 );
  *ppPage = 0;
  if( pPager->errMask & ~(PAGER_ERR_FULL) ){
................................................................................
    if( rc==SQLITE_OK ){
      rc = rc2;
    }
  }else{
    rc = pager_playback(pPager);
  }
  if( rc!=SQLITE_OK ){
    rc = SQLITE_CORRUPT_BKPT;
    pPager->errMask |= PAGER_ERR_CORRUPT;
  }
  pPager->dbSize = -1;
  return rc;
}

/*

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.418 2005/09/16 02:38:11 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Many people are failing to set -DNDEBUG=1 when compiling SQLite.
** Setting NDEBUG makes the code smaller and run faster.  So the following
................................................................................
/*
 * This global flag is set for performance testing of triggers. When it is set
 * SQLite will perform the overhead of building new and old trigger references 
 * even when no triggers exist
 */
extern int sqlite3_always_code_trigger_setup;














/*
** Internal function prototypes
*/
int sqlite3StrICmp(const char *, const char *);
int sqlite3StrNICmp(const char *, const char *, int);
int sqlite3HashNoCase(const char *, int);
int sqlite3IsNumber(const char*, int*, u8);

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.419 2005/09/17 15:20:27 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Many people are failing to set -DNDEBUG=1 when compiling SQLite.
** Setting NDEBUG makes the code smaller and run faster.  So the following
................................................................................
/*
 * This global flag is set for performance testing of triggers. When it is set
 * SQLite will perform the overhead of building new and old trigger references 
 * even when no triggers exist
 */
extern int sqlite3_always_code_trigger_setup;

/*
** The SQLITE_CORRUPT_BKPT macro can be either a constant (for production
** builds) or a function call (for debugging).  If it is a function call,
** it allows the operator to set a breakpoint at the spot where database
** corruption is first detected.
*/
#ifdef SQLITE_DEBUG
  extern int sqlite3Corrupt(void);
# define SQLITE_CORRUPT_BKPT sqlite3Corrupt()
#else
# define SQLITE_CORRUPT_BKPT SQLITE_CORRUPT
#endif

/*
** Internal function prototypes
*/
int sqlite3StrICmp(const char *, const char *);
int sqlite3StrNICmp(const char *, const char *, int);
int sqlite3HashNoCase(const char *, int);
int sqlite3IsNumber(const char*, int*, u8);

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.487 2005/09/16 02:38:11 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
    }

    /* The header should end at the start of data and the data should
    ** end at last byte of the record. If this is not the case then
    ** we are dealing with a malformed record.
    */
    if( idx!=szHdr || offset!=payloadSize ){
      rc = SQLITE_CORRUPT;
      goto op_column_out;
    }

    /* Remember all aType and aColumn information if we have a cursor
    ** to remember it in. */
    if( pC ){
      pC->payloadSize = payloadSize;
................................................................................
      /* Sanity checking.  Only the lower four bits of the flags byte should
      ** be used.  Bit 3 (mask 0x08) is unpreditable.  The lower 3 bits
      ** (mask 0x07) should be either 5 (intkey+leafdata for tables) or
      ** 2 (zerodata for indices).  If these conditions are not met it can
      ** only mean that we are dealing with a corrupt database file
      */
      if( (flags & 0xf0)!=0 || ((flags & 0x07)!=5 && (flags & 0x07)!=2) ){
        rc = SQLITE_CORRUPT;
        goto abort_due_to_error;
      }
      pCur->isTable = (flags & BTREE_INTKEY)!=0;
      pCur->isIndex = (flags & BTREE_ZERODATA)!=0;
      /* If P3==0 it means we are expected to open a table.  If P3!=0 then
      ** we expect to be opening an index.  If this is not what happened,
      ** then the database is corrupt
      */
      if( (pCur->isTable && pOp->p3type==P3_KEYINFO)
       || (pCur->isIndex && pOp->p3type!=P3_KEYINFO) ){
        rc = SQLITE_CORRUPT;
        goto abort_due_to_error;
      }
      break;
    }
    case SQLITE_EMPTY: {
      pCur->isTable = pOp->p3type!=P3_KEYINFO;
      pCur->isIndex = !pCur->isTable;
................................................................................
    ** to double the speed of the COPY operation.
    */
    int res, rx=SQLITE_OK, cnt;
    i64 x;
    cnt = 0;
    if( (sqlite3BtreeFlags(pC->pCursor)&(BTREE_INTKEY|BTREE_ZERODATA)) !=
          BTREE_INTKEY ){
      rc = SQLITE_CORRUPT;
      goto abort_due_to_error;
    }
    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_INTKEY)!=0 );
    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_ZERODATA)==0 );

#ifdef SQLITE_32BIT_ROWID
#   define MAX_ROWID 0x7fffffff

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.488 2005/09/17 15:20:28 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
    }

    /* The header should end at the start of data and the data should
    ** end at last byte of the record. If this is not the case then
    ** we are dealing with a malformed record.
    */
    if( idx!=szHdr || offset!=payloadSize ){
      rc = SQLITE_CORRUPT_BKPT;
      goto op_column_out;
    }

    /* Remember all aType and aColumn information if we have a cursor
    ** to remember it in. */
    if( pC ){
      pC->payloadSize = payloadSize;
................................................................................
      /* Sanity checking.  Only the lower four bits of the flags byte should
      ** be used.  Bit 3 (mask 0x08) is unpreditable.  The lower 3 bits
      ** (mask 0x07) should be either 5 (intkey+leafdata for tables) or
      ** 2 (zerodata for indices).  If these conditions are not met it can
      ** only mean that we are dealing with a corrupt database file
      */
      if( (flags & 0xf0)!=0 || ((flags & 0x07)!=5 && (flags & 0x07)!=2) ){
        rc = SQLITE_CORRUPT_BKPT;
        goto abort_due_to_error;
      }
      pCur->isTable = (flags & BTREE_INTKEY)!=0;
      pCur->isIndex = (flags & BTREE_ZERODATA)!=0;
      /* If P3==0 it means we are expected to open a table.  If P3!=0 then
      ** we expect to be opening an index.  If this is not what happened,
      ** then the database is corrupt
      */
      if( (pCur->isTable && pOp->p3type==P3_KEYINFO)
       || (pCur->isIndex && pOp->p3type!=P3_KEYINFO) ){
        rc = SQLITE_CORRUPT_BKPT;
        goto abort_due_to_error;
      }
      break;
    }
    case SQLITE_EMPTY: {
      pCur->isTable = pOp->p3type!=P3_KEYINFO;
      pCur->isIndex = !pCur->isTable;
................................................................................
    ** to double the speed of the COPY operation.
    */
    int res, rx=SQLITE_OK, cnt;
    i64 x;
    cnt = 0;
    if( (sqlite3BtreeFlags(pC->pCursor)&(BTREE_INTKEY|BTREE_ZERODATA)) !=
          BTREE_INTKEY ){
      rc = SQLITE_CORRUPT_BKPT;
      goto abort_due_to_error;
    }
    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_INTKEY)!=0 );
    assert( (sqlite3BtreeFlags(pC->pCursor) & BTREE_ZERODATA)==0 );

#ifdef SQLITE_32BIT_ROWID
#   define MAX_ROWID 0x7fffffff

  u32 szHdr;        /* Size of the header */
  u32 typeRowid;    /* Serial type of the rowid */
  u32 lenRowid;     /* Size of the rowid */
  Mem m, v;

  sqlite3BtreeKeySize(pCur, &nCellKey);
  if( nCellKey<=0 ){
    return SQLITE_CORRUPT;
  }
  rc = sqlite3VdbeMemFromBtree(pCur, 0, nCellKey, 1, &m);
  if( rc ){
    return rc;
  }
  sqlite3GetVarint32(m.z, &szHdr);
  sqlite3GetVarint32(&m.z[szHdr-1], &typeRowid);

  u32 szHdr;        /* Size of the header */
  u32 typeRowid;    /* Serial type of the rowid */
  u32 lenRowid;     /* Size of the rowid */
  Mem m, v;

  sqlite3BtreeKeySize(pCur, &nCellKey);
  if( nCellKey<=0 ){
    return SQLITE_CORRUPT_BKPT;
  }
  rc = sqlite3VdbeMemFromBtree(pCur, 0, nCellKey, 1, &m);
  if( rc ){
    return rc;
  }
  sqlite3GetVarint32(m.z, &szHdr);
  sqlite3GetVarint32(&m.z[szHdr-1], &typeRowid);

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements some common TCL routines used for regression
# testing the SQLite library
#
# $Id: tester.tcl,v 1.49 2005/05/26 15:20:53 danielk1977 Exp $

# Make sure tclsqlite3 was compiled correctly.  Abort now with an
# error message if not.
#
if {[sqlite3 -tcl-uses-utf]} {
  if {"\u1234"=="u1234"} {
    puts stderr "***** BUILD PROBLEM *****"
................................................................................
    puts stderr "Recompile using a TCL library and header file that match"
    puts stderr "and try again.\n**************************"
    exit 1
  }
}

set tcl_precision 15


# Use the pager codec if it is available
#
if {[sqlite3 -has-codec] && [info command sqlite_orig]==""} {
  rename sqlite3 sqlite_orig
  proc sqlite3 {args} {
    if {[llength $args]==2 && [string index [lindex $args 0] 0]!="-"} {

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements some common TCL routines used for regression
# testing the SQLite library
#
# $Id: tester.tcl,v 1.50 2005/09/17 15:20:28 drh Exp $

# Make sure tclsqlite3 was compiled correctly.  Abort now with an
# error message if not.
#
if {[sqlite3 -tcl-uses-utf]} {
  if {"\u1234"=="u1234"} {
    puts stderr "***** BUILD PROBLEM *****"
................................................................................
    puts stderr "Recompile using a TCL library and header file that match"
    puts stderr "and try again.\n**************************"
    exit 1
  }
}

set tcl_precision 15
set sqlite_pending_byte 0x0010000

# Use the pager codec if it is available
#
if {[sqlite3 -has-codec] && [info command sqlite_orig]==""} {
  rename sqlite3 sqlite_orig
  proc sqlite3 {args} {
    if {[llength $args]==2 && [string index [lindex $args 0] 0]!="-"} {