Btree *p,                                   /* The btree */
  int iTable,                                 /* Root page of table to open */
  int wrFlag,                                 /* 1 to write. 0 read-only */
  struct KeyInfo *pKeyInfo,                   /* First arg to xCompare() */
  BtCursor *pCur                              /* Write new cursor here */
){
  int rc;



  sqlite3BtreeEnter(p);
  rc = btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
  sqlite3BtreeLeave(p);

  return rc;
}

/*
** Return the size of a BtCursor object in bytes.
**
** This interfaces is needed so that users of cursors can preallocate
................................................................................
  if( pCell+info.iOverflow+3 > pPage->aData+pPage->maskPage ){
    return SQLITE_CORRUPT_BKPT;  /* Cell extends past end of page */
  }
  ovflPgno = get4byte(&pCell[info.iOverflow]);
  assert( pBt->usableSize > 4 );
  ovflPageSize = pBt->usableSize - 4;
  nOvfl = (info.nPayload - info.nLocal + ovflPageSize - 1)/ovflPageSize;
  assert( ovflPgno==0 || nOvfl>0 );


  while( nOvfl-- ){
    Pgno iNext = 0;
    MemPage *pOvfl = 0;
    if( ovflPgno<2 || ovflPgno>btreePagecount(pBt) ){
      /* 0 is not a legal page number and page 1 cannot be an 
      ** overflow page. Therefore if ovflPgno<2 or past the end of the 
      ** file the database must be corrupt. */
................................................................................
  u8 *ptr;        /* Used to move bytes around within data[] */
  int rc;         /* The return code */
  int hdr;        /* Beginning of the header.  0 most pages.  100 page 1 */

  if( *pRC ) return;

  assert( idx>=0 && idx<pPage->nCell );
  assert( sz==cellSize(pPage, idx) );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  data = pPage->aData;
  ptr = &pPage->aCellIdx[2*idx];
  pc = get2byte(ptr);
  hdr = pPage->hdrOffset;
  testcase( pc==get2byte(&data[hdr+5]) );

  Btree *p,                                   /* The btree */
  int iTable,                                 /* Root page of table to open */
  int wrFlag,                                 /* 1 to write. 0 read-only */
  struct KeyInfo *pKeyInfo,                   /* First arg to xCompare() */
  BtCursor *pCur                              /* Write new cursor here */
){
  int rc;
  if( iTable<1 ){
    rc = SQLITE_CORRUPT_BKPT;
  }else{
    sqlite3BtreeEnter(p);
    rc = btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
    sqlite3BtreeLeave(p);
  }
  return rc;
}

/*
** Return the size of a BtCursor object in bytes.
**
** This interfaces is needed so that users of cursors can preallocate
................................................................................
  if( pCell+info.iOverflow+3 > pPage->aData+pPage->maskPage ){
    return SQLITE_CORRUPT_BKPT;  /* Cell extends past end of page */
  }
  ovflPgno = get4byte(&pCell[info.iOverflow]);
  assert( pBt->usableSize > 4 );
  ovflPageSize = pBt->usableSize - 4;
  nOvfl = (info.nPayload - info.nLocal + ovflPageSize - 1)/ovflPageSize;
  assert( nOvfl>0 || 
    (CORRUPT_DB && (info.nPayload + ovflPageSize)<ovflPageSize)
  );
  while( nOvfl-- ){
    Pgno iNext = 0;
    MemPage *pOvfl = 0;
    if( ovflPgno<2 || ovflPgno>btreePagecount(pBt) ){
      /* 0 is not a legal page number and page 1 cannot be an 
      ** overflow page. Therefore if ovflPgno<2 or past the end of the 
      ** file the database must be corrupt. */
................................................................................
  u8 *ptr;        /* Used to move bytes around within data[] */
  int rc;         /* The return code */
  int hdr;        /* Beginning of the header.  0 most pages.  100 page 1 */

  if( *pRC ) return;

  assert( idx>=0 && idx<pPage->nCell );
  assert( CORRUPT_DB || sz==cellSize(pPage, idx) );
  assert( sqlite3PagerIswriteable(pPage->pDbPage) );
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  data = pPage->aData;
  ptr = &pPage->aCellIdx[2*idx];
  pc = get2byte(ptr);
  hdr = pPage->hdrOffset;
  testcase( pc==get2byte(&data[hdr+5]) );

} {12}

do_test 5.3 {
  sqlite3 db test.db
  catchsql { CREATE TABLE tx(x); }
} {1 {database disk image is malformed}}












































finish_test

} {12}

do_test 5.3 {
  sqlite3 db test.db
  catchsql { CREATE TABLE tx(x); }
} {1 {database disk image is malformed}}


#-------------------------------------------------------------------------
# Set the payload size of a cell to just less than 2^32 bytes (not
# possible in an uncorrupted db). Then try to delete the cell. At one
# point this led to an integer overflow that caused an assert() to fail.
#
reset_db
do_execsql_test 6.0 {
  PRAGMA page_size = 512;
  CREATE TABLE t1(x);
  INSERT INTO t1 VALUES(zeroblob(300));
  INSERT INTO t1 VALUES(zeroblob(600));
} {}
do_test 6.1 {
  db close
  hexio_write test.db 616 EAFFFFFF0202
  sqlite3 db test.db
  breakpoint
  execsql { DELETE FROM t1 WHERE rowid=2 }
} {}

#-------------------------------------------------------------------------
# See what happens if the sqlite_master entry associated with a PRIMARY
# KEY or UNIQUE index is removed. 
#
reset_db
do_execsql_test 7.0 {
  CREATE TABLE t1(x PRIMARY KEY, y);
  INSERT INTO t1 VALUES('a', 'A');
  INSERT INTO t1 VALUES('b', 'A');
  INSERT INTO t1 VALUES('c', 'A');
  SELECT name FROM sqlite_master;
} {t1 sqlite_autoindex_t1_1}
do_execsql_test 7.1 {
  PRAGMA writable_schema = 1;
  DELETE FROM sqlite_master WHERE name = 'sqlite_autoindex_t1_1';
}
do_test 7.2 {
  db close
  sqlite3 db test.db
  catchsql { UPDATE t1 SET x='d' AND y='D' WHERE rowid = 2 }
} {1 {database disk image is malformed}}

finish_test