Make cellSizePtr() a method on the MemPage object, with alternative

implementations depending on the page type.  This results is a small performance
improvement and size reduction.

FossilOrigin-Name: 02f7e9d7d7b93d0b6bbd6cc0d0359b3b741b9931

manifest

@@ -1,5 +1,5 @@
-C Further\s#ifdef\schanges\sin\sspeedtest1.c\sin\sorder\sto\ssupport\sSQLite\sback\sto\nversion\s3.3.9\sand\sperhaps\seven\searlier.
+C Make\scellSizePtr()\sa\smethod\son\sthe\sMemPage\sobject,\swith\salternative\nimplementations\sdepending\son\sthe\spage\stype.\s\sThis\sresults\sis\sa\ssmall\sperformance\nimprovement\sand\ssize\sreduction.
-D 2015-06-18T15:26:09.205
+D 2015-06-19T15:07:14.566
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 1063c58075b7400d93326b0eb332b48a54f53025
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -192,9 +192,9 @@ F src/auth.c b56c78ebe40a2110fd361379f7e8162d23f92240
 F src/backup.c ff743689c4d6c5cb55ad42ed9d174b2b3e71f1e3
 F src/bitvec.c 5eb7958c3bf65210211cbcfc44eff86d0ded7c9d
 F src/btmutex.c 45a968cc85afed9b5e6cf55bf1f42f8d18107f79
-F src/btree.c 02caf39192ed1f5c7157a1aac0b2ff23389233de
+F src/btree.c 960e66f4a9fd494c5712f4342432a2fb1cbb72c1
 F src/btree.h 969adc948e89e449220ff0ff724c94bb2a52e9f1
-F src/btreeInt.h 973a22a6fd61350b454ad614832b1f0a5e25a1e4
+F src/btreeInt.h 97901d5434a22344cd5ae47e80ed677bd21d572d
 F src/build.c b3f15255d5b16e42dafeaa638fd4f8a47c94ed70
 F src/callback.c 7b44ce59674338ad48b0e84e7b72f935ea4f68b0
 F src/complete.c a5cf5b4b56390cfb7b8636e8f7ddef90258dd575
@@ -1286,7 +1286,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P ed96e14adce4a4f94cc6838c46bc97937c4cb72a
+P 9246eca54adaee571dab0c066afaa604fcf9c44f
-R 4e77e4d1b1f5f9af9315f930f1585b67
+R 65525ba5a493bb8d3d370265d6f2abe8
 U drh
-Z 4a2d5290228b5807450e51ccee479c2e
+Z b80278f806bcab0592c2162609b43f46

manifest.uuid

@@ -1 +1 @@
-9246eca54adaee571dab0c066afaa604fcf9c44f
+02f7e9d7d7b93d0b6bbd6cc0d0359b3b741b9931

src/btree.c

@@ -1065,6 +1065,11 @@ static void btreeParseCell(
 ** data area of the btree-page.  The return number includes the cell
 ** data header and the local payload, but not any overflow page or
 ** the space used by the cell pointer.
+**
+** The first implementation, cellSizePtr(), handles pages that contain
+** payload, which is to say all index pages and left table pages.  The
+** second cellSizePtrNoPayload() implemention is a high-speed version
+** for pages that contain no payload - internal table pages.
 */
 static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
   u8 *pIter = pCell + pPage->childPtrSize; /* For looping over bytes of pCell */
@@ -1080,12 +1085,7 @@ static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
   btreeParseCellPtr(pPage, pCell, &debuginfo);
 #endif
 
-  if( pPage->noPayload ){
+  assert( pPage->noPayload==0 );
-    pEnd = &pIter[9];
-    while( (*pIter++)&0x80 && pIter<pEnd );
-    assert( pPage->childPtrSize==4 );
-    return (u16)(pIter - pCell);
-  }
   nSize = *pIter;
   if( nSize>=0x80 ){
     pEnd = &pIter[9];
@@ -1120,12 +1120,32 @@ static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
   assert( nSize==debuginfo.nSize || CORRUPT_DB );
   return (u16)nSize;
 }
+static u16 cellSizePtrNoPayload(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell + 4; /* For looping over bytes of pCell */
+  u8 *pEnd;              /* End mark for a varint */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  btreeParseCellPtr(pPage, pCell, &debuginfo);
+#endif
+
+  assert( pPage->childPtrSize==4 );
+  pEnd = pIter + 9;
+  while( (*pIter++)&0x80 && pIter<pEnd );
+  assert( debuginfo.nSize==(u16)(pIter - pCell) || CORRUPT_DB );
+  return (u16)(pIter - pCell);
+}
+
 
 #ifdef SQLITE_DEBUG
 /* This variation on cellSizePtr() is used inside of assert() statements
 ** only. */
 static u16 cellSize(MemPage *pPage, int iCell){
-  return cellSizePtr(pPage, findCell(pPage, iCell));
+  return pPage->xCellSize(pPage, findCell(pPage, iCell));
 }
 #endif
 
@@ -1203,7 +1223,7 @@ static int defragmentPage(MemPage *pPage){
       return SQLITE_CORRUPT_BKPT;
     }
     assert( pc>=iCellFirst && pc<=iCellLast );
-    size = cellSizePtr(pPage, &src[pc]);
+    size = pPage->xCellSize(pPage, &src[pc]);
     cbrk -= size;
     if( cbrk<iCellFirst || pc+size>usableSize ){
       return SQLITE_CORRUPT_BKPT;
@@ -1507,6 +1527,7 @@ static int decodeFlags(MemPage *pPage, int flagByte){
   pPage->leaf = (u8)(flagByte>>3);  assert( PTF_LEAF == 1<<3 );
   flagByte &= ~PTF_LEAF;
   pPage->childPtrSize = 4-4*pPage->leaf;
+  pPage->xCellSize = cellSizePtr;
   pBt = pPage->pBt;
   if( flagByte==(PTF_LEAFDATA | PTF_INTKEY) ){
     /* EVIDENCE-OF: R-03640-13415 A value of 5 means the page is an interior
@@ -1516,8 +1537,14 @@ static int decodeFlags(MemPage *pPage, int flagByte){
     ** table b-tree page. */
     assert( (PTF_LEAFDATA|PTF_INTKEY|PTF_LEAF)==13 );
     pPage->intKey = 1;
-    pPage->intKeyLeaf = pPage->leaf;
+    if( pPage->leaf ){
-    pPage->noPayload = !pPage->leaf;
+      pPage->intKeyLeaf = 1;
+      pPage->noPayload = 0;
+    }else{
+      pPage->intKeyLeaf = 0;
+      pPage->noPayload = 1;
+      pPage->xCellSize = cellSizePtrNoPayload;
+    }
     pPage->maxLocal = pBt->maxLeaf;
     pPage->minLocal = pBt->minLeaf;
   }else if( flagByte==PTF_ZERODATA ){
@@ -1624,7 +1651,7 @@ static int btreeInitPage(MemPage *pPage){
         if( pc<iCellFirst || pc>iCellLast ){
           return SQLITE_CORRUPT_BKPT;
         }
-        sz = cellSizePtr(pPage, &data[pc]);
+        sz = pPage->xCellSize(pPage, &data[pc]);
         testcase( pc+sz==usableSize );
         if( pc+sz>usableSize ){
           return SQLITE_CORRUPT_BKPT;
@@ -6096,7 +6123,7 @@ static void insertCell(
   ** wanted to be less than 4 but got rounded up to 4 on the leaf, then size
   ** might be less than 8 (leaf-size + pointer) on the interior node.  Hence
   ** the term after the || in the following assert(). */
-  assert( sz==cellSizePtr(pPage, pCell) || (sz==8 && iChild>0) );
+  assert( sz==pPage->xCellSize(pPage, pCell) || (sz==8 && iChild>0) );
   if( pPage->nOverflow || sz+2>pPage->nFree ){
     if( pTemp ){
       memcpy(pTemp, pCell, sz);
@@ -6187,8 +6214,8 @@ static void rebuildPage(
     memcpy(pData, pCell, szCell[i]);
     put2byte(pCellptr, (pData - aData));
     pCellptr += 2;
-    assert( szCell[i]==cellSizePtr(pPg, pCell) || CORRUPT_DB );
+    assert( szCell[i]==pPg->xCellSize(pPg, pCell) || CORRUPT_DB );
-    testcase( szCell[i]==cellSizePtr(pPg,pCell) );
+    testcase( szCell[i]==pPg->xCellSize(pPg,pCell) );
   }
 
   /* The pPg->nFree field is now set incorrectly. The caller will fix it. */
@@ -6478,7 +6505,7 @@ static int balance_quick(MemPage *pParent, MemPage *pPage, u8 *pSpace){
 
     u8 *pOut = &pSpace[4];
     u8 *pCell = pPage->apOvfl[0];
-    u16 szCell = cellSizePtr(pPage, pCell);
+    u16 szCell = pPage->xCellSize(pPage, pCell);
     u8 *pStop;
 
     assert( sqlite3PagerIswriteable(pNew->pDbPage) );
@@ -6784,12 +6811,12 @@ static int balance_nonroot(
     if( i+nxDiv==pParent->aiOvfl[0] && pParent->nOverflow ){
       apDiv[i] = pParent->apOvfl[0];
       pgno = get4byte(apDiv[i]);
-      szNew[i] = cellSizePtr(pParent, apDiv[i]);
+      szNew[i] = pParent->xCellSize(pParent, apDiv[i]);
       pParent->nOverflow = 0;
     }else{
       apDiv[i] = findCell(pParent, i+nxDiv-pParent->nOverflow);
       pgno = get4byte(apDiv[i]);
-      szNew[i] = cellSizePtr(pParent, apDiv[i]);
+      szNew[i] = pParent->xCellSize(pParent, apDiv[i]);
 
       /* Drop the cell from the parent page. apDiv[i] still points to
       ** the cell within the parent, even though it has been dropped.
@@ -6879,7 +6906,7 @@ static int balance_nonroot(
       for(j=0; j<limit; j++){
         assert( nCell<nMaxCells );
         apCell[nCell] = findOverflowCell(pOld, j);
-        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
+        szCell[nCell] = pOld->xCellSize(pOld, apCell[nCell]);
         nCell++;
       }
     }else{
@@ -6889,7 +6916,7 @@ static int balance_nonroot(
       for(j=0; j<limit; j++){
         assert( nCell<nMaxCells );
         apCell[nCell] = findCellv2(aData, maskPage, cellOffset, j);
-        szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
+        szCell[nCell] = pOld->xCellSize(pOld, apCell[nCell]);
         nCell++;
       }
     }       
@@ -7207,7 +7234,7 @@ static int balance_nonroot(
       */
       if( szCell[j]==4 ){
         assert(leafCorrection==4);
-        sz = cellSizePtr(pParent, pCell);
+        sz = pParent->xCellSize(pParent, pCell);
       }
     }
     iOvflSpace += sz;
@@ -7652,7 +7679,7 @@ int sqlite3BtreeInsert(
   assert( newCell!=0 );
   rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
   if( rc ) goto end_insert;
-  assert( szNew==cellSizePtr(pPage, newCell) );
+  assert( szNew==pPage->xCellSize(pPage, newCell) );
   assert( szNew <= MX_CELL_SIZE(pBt) );
   idx = pCur->aiIdx[pCur->iPage];
   if( loc==0 ){
@@ -7794,7 +7821,7 @@ int sqlite3BtreeDelete(BtCursor *pCur){
 
     pCell = findCell(pLeaf, pLeaf->nCell-1);
     if( pCell<&pLeaf->aData[4] ) return SQLITE_CORRUPT_BKPT;
-    nCell = cellSizePtr(pLeaf, pCell);
+    nCell = pLeaf->xCellSize(pLeaf, pCell);
     assert( MX_CELL_SIZE(pBt) >= nCell );
     pTmp = pBt->pTmpSpace;
     assert( pTmp!=0 );
@@ -8806,7 +8833,7 @@ static int checkTreePage(
       int pc = get2byte(&data[cellStart+i*2]);
       u32 size = 65536;
       if( pc<=usableSize-4 ){
-        size = cellSizePtr(pPage, &data[pc]);
+        size = pPage->xCellSize(pPage, &data[pc]);
       }
       if( (int)(pc+size-1)>=usableSize ){
         pCheck->zPfx = 0;

src/btreeInt.h

@@ -295,6 +295,7 @@ struct MemPage {
   u8 *aDataEnd;        /* One byte past the end of usable data */
   u8 *aCellIdx;        /* The cell index area */
   DbPage *pDbPage;     /* Pager page handle */
+  u16 (*xCellSize)(MemPage*,u8*);  /* cellSizePtr method */
   Pgno pgno;           /* Page number for this page */
 };