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Overview
Comment:Factor an "if" out of a loop in balance_nonroot() for about a 1% performance increase.
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SHA1: 1bd72d0c616e20fdb395c72ecd96579090ae26cb
User & Date: drh 2011-06-03 17:50:49
Context
2011-06-03
20:11
Create and use a function especially for adding the ParseSchema opcode. This gives a small reduction in code and a small performance increase. check-in: 957b2ab6 user: drh tags: trunk
17:50
Factor an "if" out of a loop in balance_nonroot() for about a 1% performance increase. check-in: 1bd72d0c user: drh tags: trunk
14:19
Hush some harmless compiler warnings in the URI parsing logic. check-in: 0206bc6f user: drh tags: trunk
Changes
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Changes to src/btree.c.

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** the page, 1 means the second cell, and so forth) return a pointer
** to the cell content.
**
** This routine works only for pages that do not contain overflow cells.
*/
#define findCell(P,I) \
  ((P)->aData + ((P)->maskPage & get2byte(&(P)->aData[(P)->cellOffset+2*(I)])))



/*
** This a more complex version of findCell() that works for
** pages that do contain overflow cells.
*/
static u8 *findOverflowCell(MemPage *pPage, int iCell){
  int i;
................................................................................
    ** process of being overwritten.  */
    MemPage *pOld = apCopy[i] = (MemPage*)&aSpace1[pBt->pageSize + k*i];
    memcpy(pOld, apOld[i], sizeof(MemPage));
    pOld->aData = (void*)&pOld[1];
    memcpy(pOld->aData, apOld[i]->aData, pBt->pageSize);

    limit = pOld->nCell+pOld->nOverflow;

    for(j=0; j<limit; j++){
      assert( nCell<nMaxCells );
      apCell[nCell] = findOverflowCell(pOld, j);
      szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
      nCell++;
    }











    if( i<nOld-1 && !leafData){
      u16 sz = (u16)szNew[i];
      u8 *pTemp;
      assert( nCell<nMaxCells );
      szCell[nCell] = sz;
      pTemp = &aSpace1[iSpace1];
      iSpace1 += sz;







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** the page, 1 means the second cell, and so forth) return a pointer
** to the cell content.
**
** This routine works only for pages that do not contain overflow cells.
*/
#define findCell(P,I) \
  ((P)->aData + ((P)->maskPage & get2byte(&(P)->aData[(P)->cellOffset+2*(I)])))
#define findCellv2(D,M,O,I) (D+(M&get2byte(D+(O+2*(I)))))


/*
** This a more complex version of findCell() that works for
** pages that do contain overflow cells.
*/
static u8 *findOverflowCell(MemPage *pPage, int iCell){
  int i;
................................................................................
    ** process of being overwritten.  */
    MemPage *pOld = apCopy[i] = (MemPage*)&aSpace1[pBt->pageSize + k*i];
    memcpy(pOld, apOld[i], sizeof(MemPage));
    pOld->aData = (void*)&pOld[1];
    memcpy(pOld->aData, apOld[i]->aData, pBt->pageSize);

    limit = pOld->nCell+pOld->nOverflow;
    if( pOld->nOverflow>0 ){
      for(j=0; j<limit; j++){
        assert( nCell<nMaxCells );
        apCell[nCell] = findOverflowCell(pOld, j);
        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
        nCell++;
      }
    }else{
      u8 *aData = pOld->aData;
      u16 maskPage = pOld->maskPage;
      u16 cellOffset = pOld->cellOffset;
      for(j=0; j<limit; j++){
        assert( nCell<nMaxCells );
        apCell[nCell] = findCellv2(aData, maskPage, cellOffset, j);
        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
        nCell++;
      }
    }       
    if( i<nOld-1 && !leafData){
      u16 sz = (u16)szNew[i];
      u8 *pTemp;
      assert( nCell<nMaxCells );
      szCell[nCell] = sz;
      pTemp = &aSpace1[iSpace1];
      iSpace1 += sz;