** 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 1.91 2003/04/25 13:22:52 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.
................................................................................
** must be active for both files.
**
** The size of file pBtFrom may be reduced by this operation.
** If anything goes wrong, the transaction on pBtFrom is rolled back.
*/
static int fileBtreeCopyFile(Btree *pBtTo, Btree *pBtFrom){
  int rc = SQLITE_OK;
  Pgno i, nPage;

  if( !pBtTo->inTrans || !pBtFrom->inTrans ) return SQLITE_ERROR;
  if( pBtTo->needSwab!=pBtFrom->needSwab ) return SQLITE_ERROR;
  if( pBtTo->pCursor ) return SQLITE_BUSY;
  memcpy(pBtTo->page1, pBtFrom->page1, SQLITE_PAGE_SIZE);
  sqlitepager_overwrite(pBtTo->pPager, 1, pBtFrom->page1);

  nPage = sqlitepager_pagecount(pBtFrom->pPager);
  for(i=2; i<=nPage; i++){
    void *pPage;
    rc = sqlitepager_get(pBtFrom->pPager, i, &pPage);
    if( rc ) break;
    sqlitepager_overwrite(pBtTo->pPager, i, pPage);

    sqlitepager_unref(pPage);
  }









  if( !rc ) rc = sqlitepager_truncate(pBtTo->pPager, nPage);

  if( rc ){
    fileBtreeRollback(pBtTo);
  }
  return rc;  
}

/*

** 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 1.92 2003/04/25 15:37:58 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.
................................................................................
** must be active for both files.
**
** The size of file pBtFrom may be reduced by this operation.
** If anything goes wrong, the transaction on pBtFrom is rolled back.
*/
static int fileBtreeCopyFile(Btree *pBtTo, Btree *pBtFrom){
  int rc = SQLITE_OK;
  Pgno i, nPage, nToPage;

  if( !pBtTo->inTrans || !pBtFrom->inTrans ) return SQLITE_ERROR;
  if( pBtTo->needSwab!=pBtFrom->needSwab ) return SQLITE_ERROR;
  if( pBtTo->pCursor ) return SQLITE_BUSY;
  memcpy(pBtTo->page1, pBtFrom->page1, SQLITE_PAGE_SIZE);
  rc = sqlitepager_overwrite(pBtTo->pPager, 1, pBtFrom->page1);
  nToPage = sqlitepager_pagecount(pBtTo->pPager);
  nPage = sqlitepager_pagecount(pBtFrom->pPager);
  for(i=2; rc==SQLITE_OK && i<=nPage; i++){
    void *pPage;
    rc = sqlitepager_get(pBtFrom->pPager, i, &pPage);
    if( rc ) break;
    rc = sqlitepager_overwrite(pBtTo->pPager, i, pPage);
    if( rc ) break;
    sqlitepager_unref(pPage);
  }
  for(i=nPage+1; rc==SQLITE_OK && i<=nToPage; i++){
    void *pPage;
    rc = sqlitepager_get(pBtTo->pPager, i, &pPage);
    if( rc ) break;
    rc = sqlitepager_write(pPage);
    sqlitepager_unref(pPage);
    sqlitepager_dont_write(pBtTo->pPager, i);
  }
  if( !rc && nPage<nToPage ){
    rc = sqlitepager_truncate(pBtTo->pPager, nPage);
  }
  if( rc ){
    fileBtreeRollback(pBtTo);
  }
  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 1.82 2003/04/25 13:22:53 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
static int syncAllPages(Pager*);

/*
** Truncate the file to the number of pages specified.
*/
int sqlitepager_truncate(Pager *pPager, Pgno nPage){
  int rc;

  if( pPager->dbSize<0 ) sqlitepager_pagecount(pPager);





  if( nPage>=pPager->dbSize ){
    return SQLITE_OK;
  }
  syncAllPages(pPager);
  rc = sqliteOsTruncate(&pPager->fd, SQLITE_PAGE_SIZE*(off_t)nPage);
  if( rc==SQLITE_OK ){
    pPager->dbSize = nPage;
................................................................................
  PgHdr *pPg;
  int rc;

  /* Make sure we have not hit any critical errors.
  */ 
  assert( pPager!=0 );
  assert( pgno!=0 );

  if( pPager->errMask & ~(PAGER_ERR_FULL) ){
    return pager_errcode(pPager);
  }

  /* If this is the first page accessed, then get a read lock
  ** on the database file.
  */
  if( pPager->nRef==0 ){
    rc = sqliteOsReadLock(&pPager->fd);
    if( rc!=SQLITE_OK ){
      *ppPage = 0;
      return rc;
    }
    pPager->state = SQLITE_READLOCK;

    /* If a journal file exists, try to play it back.
    */
    if( pPager->useJournal && sqliteOsFileExists(pPager->zJournal) ){
................................................................................
       */
       rc = sqliteOsWriteLock(&pPager->fd);
       if( rc!=SQLITE_OK ){
         if( sqliteOsUnlock(&pPager->fd)!=SQLITE_OK ){
           /* This should never happen! */
           rc = SQLITE_INTERNAL;
         }
         *ppPage = 0;
         return rc;
       }
       pPager->state = SQLITE_WRITELOCK;

       /* Open the journal for exclusive access.  Return SQLITE_BUSY if
       ** we cannot get exclusive access to the journal file. 
       **
................................................................................
       ** we have to open the journal for writing in order to obtain an
       ** exclusive access lock.
       */
       rc = sqliteOsOpenReadWrite(pPager->zJournal, &pPager->jfd, &dummy);
       if( rc!=SQLITE_OK ){
         rc = sqliteOsUnlock(&pPager->fd);
         assert( rc==SQLITE_OK );
         *ppPage = 0;
         return SQLITE_BUSY;
       }
       pPager->journalOpen = 1;
       pPager->journalStarted = 0;

       /* Playback and delete the journal.  Drop the database write
       ** lock and reacquire the read lock.
................................................................................
    int h;
    pPager->nMiss++;
    if( pPager->nPage<pPager->mxPage || pPager->pFirst==0 ){
      /* Create a new page */
      pPg = sqliteMallocRaw( sizeof(*pPg) + SQLITE_PAGE_SIZE 
                              + sizeof(u32) + pPager->nExtra );
      if( pPg==0 ){
        *ppPage = 0;
        pager_unwritelock(pPager);
        pPager->errMask |= PAGER_ERR_MEM;
        return SQLITE_NOMEM;
      }
      memset(pPg, 0, sizeof(*pPg));
      pPg->pPager = pPager;
      pPg->pNextAll = pPager->pAll;
................................................................................
      ** very slow operation, so we work hard to avoid it.  But sometimes
      ** it can't be helped.
      */
      if( pPg==0 ){
        int rc = syncAllPages(pPager);
        if( rc!=0 ){
          sqlitepager_rollback(pPager);
          *ppPage = 0;
          return SQLITE_IOERR;
        }
        pPg = pPager->pFirst;
      }
      assert( pPg->nRef==0 );

      /* Write the page to the database file if it is dirty.
................................................................................
      */
      if( pPg->dirty ){
        assert( pPg->needSync==0 );
        pPg->pDirty = 0;
        rc = pager_write_pagelist( pPg );
        if( rc!=SQLITE_OK ){
          sqlitepager_rollback(pPager);
          *ppPage = 0;
          return SQLITE_IOERR;
        }
      }
      assert( pPg->dirty==0 );

      /* If the page we are recycling is marked as alwaysRollback, then
      ** set the global alwaysRollback flag, thus disabling the
................................................................................
    h = pager_hash(pgno);
    pPg->pNextHash = pPager->aHash[h];
    pPager->aHash[h] = pPg;
    if( pPg->pNextHash ){
      assert( pPg->pNextHash->pPrevHash==0 );
      pPg->pNextHash->pPrevHash = pPg;
    }



    if( pPager->dbSize<0 ) sqlitepager_pagecount(pPager);





    if( pPager->dbSize<(int)pgno ){
      memset(PGHDR_TO_DATA(pPg), 0, SQLITE_PAGE_SIZE);
    }else{
      int rc;
      sqliteOsSeek(&pPager->fd, (pgno-1)*(off_t)SQLITE_PAGE_SIZE);
      rc = sqliteOsRead(&pPager->fd, PGHDR_TO_DATA(pPg), SQLITE_PAGE_SIZE);
      if( rc!=SQLITE_OK ){
        off_t fileSize;
        if( sqliteOsFileSize(&pPager->fd,&fileSize)!=SQLITE_OK
               || fileSize>=pgno*SQLITE_PAGE_SIZE ){

          return rc;
        }else{
          memset(PGHDR_TO_DATA(pPg), 0, SQLITE_PAGE_SIZE);
        }
      }
    }
    if( pPager->nExtra>0 ){
      memset(PGHDR_TO_EXTRA(pPg), 0, pPager->nExtra);
    }
  }else{
    /* The requested page is in the page cache. */
    pPager->nHit++;
    page_ref(pPg);
  }
  *ppPage = PGHDR_TO_DATA(pPg);
  return SQLITE_OK;
................................................................................
  }
  pPager->journalOpen = 1;
  pPager->journalStarted = 0;
  pPager->needSync = 0;
  pPager->alwaysRollback = 0;
  pPager->nRec = 0;
  sqlitepager_pagecount(pPager);




  pPager->origDbSize = pPager->dbSize;
  if( journal_format==JOURNAL_FORMAT_3 ){
    rc = sqliteOsWrite(&pPager->jfd, aJournalMagic3, sizeof(aJournalMagic3));
    if( rc==SQLITE_OK ){
      rc = write32bits(&pPager->jfd, pPager->noSync ? 0xffffffff : 0);
    }
    if( rc==SQLITE_OK ){

** 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 1.83 2003/04/25 15:37:58 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
static int syncAllPages(Pager*);

/*
** Truncate the file to the number of pages specified.
*/
int sqlitepager_truncate(Pager *pPager, Pgno nPage){
  int rc;
  if( pPager->dbSize<0 ){
    sqlitepager_pagecount(pPager);
  }
  if( pPager->errMask!=0 ){
    rc = pager_errcode(pPager);
    return rc;
  }
  if( nPage>=pPager->dbSize ){
    return SQLITE_OK;
  }
  syncAllPages(pPager);
  rc = sqliteOsTruncate(&pPager->fd, SQLITE_PAGE_SIZE*(off_t)nPage);
  if( rc==SQLITE_OK ){
    pPager->dbSize = nPage;
................................................................................
  PgHdr *pPg;
  int rc;

  /* Make sure we have not hit any critical errors.
  */ 
  assert( pPager!=0 );
  assert( pgno!=0 );
  *ppPage = 0;
  if( pPager->errMask & ~(PAGER_ERR_FULL) ){
    return pager_errcode(pPager);
  }

  /* If this is the first page accessed, then get a read lock
  ** on the database file.
  */
  if( pPager->nRef==0 ){
    rc = sqliteOsReadLock(&pPager->fd);
    if( rc!=SQLITE_OK ){

      return rc;
    }
    pPager->state = SQLITE_READLOCK;

    /* If a journal file exists, try to play it back.
    */
    if( pPager->useJournal && sqliteOsFileExists(pPager->zJournal) ){
................................................................................
       */
       rc = sqliteOsWriteLock(&pPager->fd);
       if( rc!=SQLITE_OK ){
         if( sqliteOsUnlock(&pPager->fd)!=SQLITE_OK ){
           /* This should never happen! */
           rc = SQLITE_INTERNAL;
         }

         return rc;
       }
       pPager->state = SQLITE_WRITELOCK;

       /* Open the journal for exclusive access.  Return SQLITE_BUSY if
       ** we cannot get exclusive access to the journal file. 
       **
................................................................................
       ** we have to open the journal for writing in order to obtain an
       ** exclusive access lock.
       */
       rc = sqliteOsOpenReadWrite(pPager->zJournal, &pPager->jfd, &dummy);
       if( rc!=SQLITE_OK ){
         rc = sqliteOsUnlock(&pPager->fd);
         assert( rc==SQLITE_OK );

         return SQLITE_BUSY;
       }
       pPager->journalOpen = 1;
       pPager->journalStarted = 0;

       /* Playback and delete the journal.  Drop the database write
       ** lock and reacquire the read lock.
................................................................................
    int h;
    pPager->nMiss++;
    if( pPager->nPage<pPager->mxPage || pPager->pFirst==0 ){
      /* Create a new page */
      pPg = sqliteMallocRaw( sizeof(*pPg) + SQLITE_PAGE_SIZE 
                              + sizeof(u32) + pPager->nExtra );
      if( pPg==0 ){

        pager_unwritelock(pPager);
        pPager->errMask |= PAGER_ERR_MEM;
        return SQLITE_NOMEM;
      }
      memset(pPg, 0, sizeof(*pPg));
      pPg->pPager = pPager;
      pPg->pNextAll = pPager->pAll;
................................................................................
      ** very slow operation, so we work hard to avoid it.  But sometimes
      ** it can't be helped.
      */
      if( pPg==0 ){
        int rc = syncAllPages(pPager);
        if( rc!=0 ){
          sqlitepager_rollback(pPager);

          return SQLITE_IOERR;
        }
        pPg = pPager->pFirst;
      }
      assert( pPg->nRef==0 );

      /* Write the page to the database file if it is dirty.
................................................................................
      */
      if( pPg->dirty ){
        assert( pPg->needSync==0 );
        pPg->pDirty = 0;
        rc = pager_write_pagelist( pPg );
        if( rc!=SQLITE_OK ){
          sqlitepager_rollback(pPager);

          return SQLITE_IOERR;
        }
      }
      assert( pPg->dirty==0 );

      /* If the page we are recycling is marked as alwaysRollback, then
      ** set the global alwaysRollback flag, thus disabling the
................................................................................
    h = pager_hash(pgno);
    pPg->pNextHash = pPager->aHash[h];
    pPager->aHash[h] = pPg;
    if( pPg->pNextHash ){
      assert( pPg->pNextHash->pPrevHash==0 );
      pPg->pNextHash->pPrevHash = pPg;
    }
    if( pPager->nExtra>0 ){
      memset(PGHDR_TO_EXTRA(pPg), 0, pPager->nExtra);
    }
    if( pPager->dbSize<0 ) sqlitepager_pagecount(pPager);
    if( pPager->errMask!=0 ){
      sqlitepager_unref(PGHDR_TO_DATA(pPg));
      rc = pager_errcode(pPager);
      return rc;
    }
    if( pPager->dbSize<(int)pgno ){
      memset(PGHDR_TO_DATA(pPg), 0, SQLITE_PAGE_SIZE);
    }else{
      int rc;
      sqliteOsSeek(&pPager->fd, (pgno-1)*(off_t)SQLITE_PAGE_SIZE);
      rc = sqliteOsRead(&pPager->fd, PGHDR_TO_DATA(pPg), SQLITE_PAGE_SIZE);
      if( rc!=SQLITE_OK ){
        off_t fileSize;
        if( sqliteOsFileSize(&pPager->fd,&fileSize)!=SQLITE_OK
               || fileSize>=pgno*SQLITE_PAGE_SIZE ){
          sqlitepager_unref(PGHDR_TO_DATA(pPg));
          return rc;
        }else{
          memset(PGHDR_TO_DATA(pPg), 0, SQLITE_PAGE_SIZE);
        }
      }
    }



  }else{
    /* The requested page is in the page cache. */
    pPager->nHit++;
    page_ref(pPg);
  }
  *ppPage = PGHDR_TO_DATA(pPg);
  return SQLITE_OK;
................................................................................
  }
  pPager->journalOpen = 1;
  pPager->journalStarted = 0;
  pPager->needSync = 0;
  pPager->alwaysRollback = 0;
  pPager->nRec = 0;
  sqlitepager_pagecount(pPager);
  if( pPager->errMask!=0 ){
    rc = pager_errcode(pPager);
    return rc;
  }
  pPager->origDbSize = pPager->dbSize;
  if( journal_format==JOURNAL_FORMAT_3 ){
    rc = sqliteOsWrite(&pPager->jfd, aJournalMagic3, sizeof(aJournalMagic3));
    if( rc==SQLITE_OK ){
      rc = write32bits(&pPager->jfd, pPager->noSync ? 0xffffffff : 0);
    }
    if( rc==SQLITE_OK ){

**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.5 2003/04/25 13:22:53 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"

#define SQLITE_OMIT_VACUUM 1

/*
................................................................................
  if( execsql(pParse, db, "BEGIN") ) goto end_of_vacuum;
  if( execsql(pParse, dbNew, "PRAGMA synchronous=off; BEGIN") ){
    goto end_of_vacuum;
  }
  sVac.dbOld = db;
  sVac.dbNew = dbNew;
  sVac.pParse = pParse;
  for(i=0; i<sizeof(zPragma)/sizeof(zPragma[0]); i++){
    char zBuf[200];
    assert( strlen(zPragma[i])<100 );
    sprintf(zBuf, "PRAGMA %s;", zPragma[i]);
    sVac.zPragma = zPragma[i];
    rc = sqlite_exec(db, zBuf, vacuumCallback3, &sVac, &zErrMsg);
    if( rc ) goto vacuum_error;
  }
  if( rc==SQLITE_OK ){

    rc = sqlite_exec(db, "SELECT type, name, sql FROM sqlite_master "
             "WHERE sql NOT NULL", vacuumCallback1, &sVac, &zErrMsg);
  }
  if( rc ){
    if( pParse->zErrMsg==0 ){
      sqliteErrorMsg(pParse, "unable to vacuum database - %s", zErrMsg);
    }
    goto end_of_vacuum;
  }
  rc = sqliteBtreeCopyFile(db->aDb[0].pBt, dbNew->aDb[0].pBt);
  sqlite_exec(db, "COMMIT", 0, 0, 0);

  sqliteResetInternalSchema(db, 0);


end_of_vacuum:
  sqlite_exec(db, "COMMIT", 0, 0, 0);



  if( safety ) {


    sqliteSafetyOn(db);
  }
  if( dbNew ) sqlite_close(dbNew);
  sqliteOsDelete(zTemp);
  sqliteFree(zTemp);
  sqliteFree(sVac.s1.z);
  sqliteFree(sVac.s2.z);
  if( zErrMsg ) sqlite_freemem(zErrMsg);
  return;

vacuum_error:
#endif
}

**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.6 2003/04/25 15:37:58 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"

#define SQLITE_OMIT_VACUUM 1

/*
................................................................................
  if( execsql(pParse, db, "BEGIN") ) goto end_of_vacuum;
  if( execsql(pParse, dbNew, "PRAGMA synchronous=off; BEGIN") ){
    goto end_of_vacuum;
  }
  sVac.dbOld = db;
  sVac.dbNew = dbNew;
  sVac.pParse = pParse;
  for(i=0; rc==SQLITE_OK && i<sizeof(zPragma)/sizeof(zPragma[0]); i++){
    char zBuf[200];
    assert( strlen(zPragma[i])<100 );
    sprintf(zBuf, "PRAGMA %s;", zPragma[i]);
    sVac.zPragma = zPragma[i];
    rc = sqlite_exec(db, zBuf, vacuumCallback3, &sVac, &zErrMsg);

  }

  if( !rc ){
    rc = sqlite_exec(db, "SELECT type, name, sql FROM sqlite_master "
             "WHERE sql NOT NULL", vacuumCallback1, &sVac, &zErrMsg);
  }
  if( !rc ){





    rc = sqliteBtreeCopyFile(db->aDb[0].pBt, dbNew->aDb[0].pBt);
    sqlite_exec(db, "COMMIT", 0, 0, 0);
    sqlite_exec(db, "ROLLBACK", 0, 0, 0);  /* In case the COMMIT failed */
    sqliteResetInternalSchema(db, 0);
  }

end_of_vacuum:

  if( rc && pParse->zErrMsg==0 && zErrMsg!=0 ){
    sqliteErrorMsg(pParse, "unable to vacuum database - %s", zErrMsg);
  }
  if( safety ) {
    sqlite_exec(db, "COMMIT", 0, 0, 0);
    sqlite_exec(db, "ROLLBACK", 0, 0, 0);  /* In case the COMMIT failed */
    sqliteSafetyOn(db);
  }
  if( dbNew ) sqlite_close(dbNew);
  sqliteOsDelete(zTemp);
  sqliteFree(zTemp);
  sqliteFree(sVac.s1.z);
  sqliteFree(sVac.s2.z);
  if( zErrMsg ) sqlite_freemem(zErrMsg);
  return;


#endif
}

**
** 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 1.219 2003/04/23 12:25:25 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The makefile scans this source file and creates the following
** array of string constants which are the names of all VDBE opcodes.
................................................................................
  Cursor *pC;
  BtCursor *pCrsr;

  assert( i>=0 && i<p->nCursor );
  pC = &p->aCsr[i];
  if( (pCrsr = pC->pCursor)!=0 ){
    int res;
    sqliteBtreeLast(pCrsr, &res);
    p->aCsr[i].nullRow = res;
    if( res && pOp->p2>0 ){
      pc = pOp->p2 - 1;
    }
  }else{
    pC->nullRow = 0;
  }
................................................................................
  Cursor *pC;
  BtCursor *pCrsr;

  assert( i>=0 && i<p->nCursor );
  pC = &p->aCsr[i];
  if( (pCrsr = pC->pCursor)!=0 ){
    int res;
    sqliteBtreeFirst(pCrsr, &res);
    pC->atFirst = res==0;
    pC->nullRow = res;
    if( res && pOp->p2>0 ){
      pc = pOp->p2 - 1;
    }
  }else{
    pC->nullRow = 0;

**
** 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 1.220 2003/04/25 15:37:58 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** The makefile scans this source file and creates the following
** array of string constants which are the names of all VDBE opcodes.
................................................................................
  Cursor *pC;
  BtCursor *pCrsr;

  assert( i>=0 && i<p->nCursor );
  pC = &p->aCsr[i];
  if( (pCrsr = pC->pCursor)!=0 ){
    int res;
    rc = sqliteBtreeLast(pCrsr, &res);
    p->aCsr[i].nullRow = res;
    if( res && pOp->p2>0 ){
      pc = pOp->p2 - 1;
    }
  }else{
    pC->nullRow = 0;
  }
................................................................................
  Cursor *pC;
  BtCursor *pCrsr;

  assert( i>=0 && i<p->nCursor );
  pC = &p->aCsr[i];
  if( (pCrsr = pC->pCursor)!=0 ){
    int res;
    rc = sqliteBtreeFirst(pCrsr, &res);
    pC->atFirst = res==0;
    pC->nullRow = res;
    if( res && pOp->p2>0 ){
      pc = pOp->p2 - 1;
    }
  }else{
    pC->nullRow = 0;

# This file implements regression tests for SQLite library.  The
# focus of this file is testing for correct handling of I/O errors
# such as writes failing because the disk is full.
# 
# The tests in this file use special facilities that are only
# available in the SQLite test fixture.
#
# $Id: ioerr.test,v 1.2 2003/02/16 22:21:33 drh Exp $

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

set ::go 1
for {set n 1} {$go} {incr n} {
  do_test ioerr-1.$n.1 {
................................................................................
    # if {$r} {puts $msg}
    set ::go [expr {$::sqlite_io_error_pending<=0}]
    expr {$::sqlite_io_error_pending>0 || $r!=0}
  } {1}
}
set ::sqlite_io_error_pending 0






























































finish_test

# This file implements regression tests for SQLite library.  The
# focus of this file is testing for correct handling of I/O errors
# such as writes failing because the disk is full.
# 
# The tests in this file use special facilities that are only
# available in the SQLite test fixture.
#
# $Id: ioerr.test,v 1.3 2003/04/25 15:37:59 drh Exp $

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

set ::go 1
for {set n 1} {$go} {incr n} {
  do_test ioerr-1.$n.1 {
................................................................................
    # if {$r} {puts $msg}
    set ::go [expr {$::sqlite_io_error_pending<=0}]
    expr {$::sqlite_io_error_pending>0 || $r!=0}
  } {1}
}
set ::sqlite_io_error_pending 0

proc cksum {{db db}} {
  set txt [$db eval {SELECT name, type, sql FROM sqlite_master}]\n
  foreach tbl [$db eval {SELECT name FROM sqlite_master WHERE type='table'}] {
    append txt [$db eval "SELECT * FROM $tbl"]\n
  }
  foreach prag {default_synchronous default_cache_size} {
    append txt $prag-[$db eval "PRAGMA $prag"]\n
  }
  set cksum [string length $txt]-[md5 $txt]
  # puts $cksum-[file size test.db]
  return $cksum
}

set ::go 1
for {set n 1} {$go} {incr n} {
  do_test ioerr-2.$n.1 {
    set ::sqlite_io_error_pending 0
    db close
    catch {file delete -force test.db}
    catch {file delete -force test.db-journal}
    sqlite db test.db
    execsql {
      BEGIN;
      CREATE TABLE t1(a, b, c);
      INSERT INTO t1 VALUES(1, randstr(5,50), randstr(5,50));
      INSERT INTO t1 SELECT a+2, b||'-'||rowid, c||'-'||rowid FROM t1;
      INSERT INTO t1 SELECT a+4, b||'-'||rowid, c||'-'||rowid FROM t1;
      INSERT INTO t1 SELECT a+8, b||'-'||rowid, c||'-'||rowid FROM t1;
      INSERT INTO t1 SELECT a+16, b||'-'||rowid, c||'-'||rowid FROM t1;
      INSERT INTO t1 SELECT a+32, b||'-'||rowid, c||'-'||rowid FROM t1;
      INSERT INTO t1 SELECT a+64, b||'-'||rowid, c||'-'||rowid FROM t1;
      INSERT INTO t1 SELECT a+128, b||'-'||rowid, c||'-'||rowid FROM t1;
      CREATE TABLE t2 AS SELECT * FROM t1;
      CREATE TABLE t3 AS SELECT * FROM t1;
      COMMIT;
      DROP TABLE t2;
    }
    set ::cksum [cksum]
    execsql {
      SELECT name FROM sqlite_master WHERE type='table'
    }
  } {t1 t3}
  do_test ioerr-2.$n.2 [subst {
    set ::sqlite_io_error_pending $n
  }] $n
  do_test ioerr-2.$n.3 {
    set r [catch {db eval {
      VACUUM;
    }} msg]
    # puts "error_pending=$::sqlite_io_error_pending"
    # if {$r} {puts $msg}
    set ::go [expr {$::sqlite_io_error_pending<=0}]
    expr {$::sqlite_io_error_pending>0 || $r!=0}
    set ::sqlite_io_error_pending 0
    db close
    sqlite db test.db
    cksum
  } $cksum
}
set ::sqlite_io_error_pending 0

finish_test