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Overview
Comment:Fix a compiler warning when SQLITE_DIRECT_OVERFLOW_READ is defined. Minor performance enhancement and size reduction.
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Timelines: family | ancestors | descendants | both | overflow-pgno-cache
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SHA1: 96385dc460545807a5c8fcf6280a971700f84866
User & Date: drh 2014-03-31 23:57:41.627
Context
2014-04-01
01:24
Remove an unnecessary conditional, replacing it with an assert(). Improvements to comments. (Closed-Leaf check-in: 834bf1c367 user: drh tags: overflow-pgno-cache)
2014-03-31
23:57
Fix a compiler warning when SQLITE_DIRECT_OVERFLOW_READ is defined. Minor performance enhancement and size reduction. (check-in: 96385dc460 user: drh tags: overflow-pgno-cache)
22:03
Merge in the latest changes and fixes from trunk. (check-in: f6211540c9 user: drh tags: overflow-pgno-cache)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btree.c.
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  /* Now that no other errors can occur, finish filling in the BtCursor
  ** variables and link the cursor into the BtShared list.  */
  pCur->pgnoRoot = (Pgno)iTable;
  pCur->iPage = -1;
  pCur->pKeyInfo = pKeyInfo;
  pCur->pBtree = p;
  pCur->pBt = pBt;

  pCur->curFlags = wrFlag ? BTCF_WriteFlag : 0;
  pCur->pNext = pBt->pCursor;
  if( pCur->pNext ){
    pCur->pNext->pPrev = pCur;
  }
  pBt->pCursor = pCur;
  pCur->eState = CURSOR_INVALID;
  return SQLITE_OK;








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  /* Now that no other errors can occur, finish filling in the BtCursor
  ** variables and link the cursor into the BtShared list.  */
  pCur->pgnoRoot = (Pgno)iTable;
  pCur->iPage = -1;
  pCur->pKeyInfo = pKeyInfo;
  pCur->pBtree = p;
  pCur->pBt = pBt;
  assert( wrFlag==0 || wrFlag==BTCF_WriteFlag );
  pCur->curFlags = wrFlag;
  pCur->pNext = pBt->pCursor;
  if( pCur->pNext ){
    pCur->pNext->pPrev = pCur;
  }
  pBt->pCursor = pCur;
  pCur->eState = CURSOR_INVALID;
  return SQLITE_OK;
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){
  unsigned char *aPayload;
  int rc = SQLITE_OK;
  u32 nKey;
  int iIdx = 0;
  MemPage *pPage = pCur->apPage[pCur->iPage]; /* Btree page of current entry */
  BtShared *pBt = pCur->pBt;                  /* Btree this cursor belongs to */

  int bEnd;                       /* True if reading to end of data */


  assert( pPage );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
  assert( cursorHoldsMutex(pCur) );

  getCellInfo(pCur);
  aPayload = pCur->info.pCell + pCur->info.nHeader;
  nKey = (pPage->intKey ? 0 : (int)pCur->info.nKey);

  bEnd = (offset+amt==nKey+pCur->info.nData);


  if( NEVER(offset+amt > nKey+pCur->info.nData) 
   || &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
  ){
    /* Trying to read or write past the end of the data is an error */
    return SQLITE_CORRUPT_BKPT;
  }








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){
  unsigned char *aPayload;
  int rc = SQLITE_OK;
  u32 nKey;
  int iIdx = 0;
  MemPage *pPage = pCur->apPage[pCur->iPage]; /* Btree page of current entry */
  BtShared *pBt = pCur->pBt;                  /* Btree this cursor belongs to */
#ifdef SQLITE_DIRECT_OVERFLOW_READ
  int bEnd;                                   /* True if reading to end of data */
#endif

  assert( pPage );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->aiIdx[pCur->iPage]<pPage->nCell );
  assert( cursorHoldsMutex(pCur) );

  getCellInfo(pCur);
  aPayload = pCur->info.pCell + pCur->info.nHeader;
  nKey = (pPage->intKey ? 0 : (int)pCur->info.nKey);
#ifdef SQLITE_DIRECT_OVERFLOW_READ
  bEnd = (offset+amt==nKey+pCur->info.nData);
#endif

  if( NEVER(offset+amt > nKey+pCur->info.nData) 
   || &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
  ){
    /* Trying to read or write past the end of the data is an error */
    return SQLITE_CORRUPT_BKPT;
  }
︙︙
Changes to src/btreeInt.h.
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  u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
};

/*
** Legal values for BtCursor.curFlags
*/

#define BTCF_ValidNKey    0x01   /* True if info.nKey is valid */
#define BTCF_ValidOvfl    0x02   /* True if aOverflow is valid */
#define BTCF_AtLast       0x04   /* Cursor is pointing ot the last entry */
#define BTCF_WriteFlag    0x08   /* True if a write cursor */
#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */

/*
** Potential values for BtCursor.eState.
**
** CURSOR_INVALID:
**   Cursor does not point to a valid entry. This can happen (for example) 








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  u16 aiIdx[BTCURSOR_MAX_DEPTH];        /* Current index in apPage[i] */
  MemPage *apPage[BTCURSOR_MAX_DEPTH];  /* Pages from root to current page */
};

/*
** Legal values for BtCursor.curFlags
*/
#define BTCF_WriteFlag    0x01   /* True if a write cursor */
#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
#define BTCF_AtLast       0x08   /* Cursor is pointing ot the last entry */

#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */

/*
** Potential values for BtCursor.eState.
**
** CURSOR_INVALID:
**   Cursor does not point to a valid entry. This can happen (for example)
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