Reduce the size of the CellInfo object from 32 to 24 bytes on 64-bit machines,

for a small performance increase and library size reduction.

FossilOrigin-Name: 6a4cfc7ab62046eb718ce59eff6b632f239312ac

manifest

@@ -1,5 +1,5 @@
-C Enhance\sthe\scommand-line\sshell\sso\sthat\sit\scan\shandle\sMBCS\scharacters\son\s\ninput\sand\soutput.
-D 2015-12-30T17:03:40.996
+C Reduce\sthe\ssize\sof\sthe\sCellInfo\sobject\sfrom\s32\sto\s24\sbytes\son\s64-bit\smachines,\nfor\sa\ssmall\sperformance\sincrease\sand\slibrary\ssize\sreduction.
+D 2015-12-30T18:18:46.481
 F Makefile.in 28bcd6149e050dff35d4dcfd97e890cd387a499d
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 5fff077fcc46de7714ed6eebb6159a4c00eab751
@@ -276,9 +276,9 @@ F src/auth.c b56c78ebe40a2110fd361379f7e8162d23f92240
 F src/backup.c 2869a76c03eb393ee795416e2387005553df72bc
 F src/bitvec.c 1a78d450a17c5016710eec900bedfc5729bf9bdf
 F src/btmutex.c 45a968cc85afed9b5e6cf55bf1f42f8d18107f79
-F src/btree.c 84ede51e371a11c3dbb3e24ccc5e3e99594a6c00
+F src/btree.c 5ac3f868d4f20a67f0f00a1014940f902b511558
 F src/btree.h 2d76dee44704c47eed323356a758662724b674a0
-F src/btreeInt.h 3ab435ed27adea54d040584b0bcc488ee7db1e38
+F src/btreeInt.h b5f2651b41808f038dee9282c5dc0232ce6532d3
 F src/build.c 5a8611a01cbf67c736d81304e054ec361ef8963d
 F src/callback.c 7b44ce59674338ad48b0e84e7b72f935ea4f68b0
 F src/complete.c addcd8160b081131005d5bc2d34adf20c1c5c92f
@@ -1406,8 +1406,8 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 2081d75767dc590b4c8457e5f8e5f18ba5f8eaa7 a0a08b8c0bbd4d71955261f6b7e997701ca68e18
-R 7ece1114510edab4a5d304cc0b06015c
-T +closed a0a08b8c0bbd4d71955261f6b7e997701ca68e18
+P 3d81dfe3bc5ca9588b7796769d9be7a182f38b1c 7850715406458a61cff9eba5ad915f61f6d99482
+R 53c67154b7bbcd33ca0c18e39c81df1f
+T +closed 7850715406458a61cff9eba5ad915f61f6d99482
 U drh
-Z 175aed9e7444f5a5f7c550af284b6e58
+Z f674907b91bbe0647e025dbc39f72b55

manifest.uuid

@@ -1 +1 @@
-3d81dfe3bc5ca9588b7796769d9be7a182f38b1c
+6a4cfc7ab62046eb718ce59eff6b632f239312ac

src/btree.c

@@ -1051,8 +1051,7 @@ static SQLITE_NOINLINE void btreeParseCellAdjustSizeForOverflow(
   }else{
     pInfo->nLocal = (u16)minLocal;
   }
-  pInfo->iOverflow = (u16)(&pInfo->pPayload[pInfo->nLocal] - pCell);
-  pInfo->nSize = pInfo->iOverflow + 4;
+  pInfo->nSize = (u16)(&pInfo->pPayload[pInfo->nLocal] - pCell) + 4;
 }
 
 /*
@@ -1084,7 +1083,6 @@ static void btreeParseCellPtrNoPayload(
   pInfo->nSize = 4 + getVarint(&pCell[4], (u64*)&pInfo->nKey);
   pInfo->nPayload = 0;
   pInfo->nLocal = 0;
-  pInfo->iOverflow = 0;
   pInfo->pPayload = 0;
   return;
 }
@@ -1154,7 +1152,6 @@ static void btreeParseCellPtr(
     pInfo->nSize = nPayload + (u16)(pIter - pCell);
     if( pInfo->nSize<4 ) pInfo->nSize = 4;
     pInfo->nLocal = (u16)nPayload;
-    pInfo->iOverflow = 0;
   }else{
     btreeParseCellAdjustSizeForOverflow(pPage, pCell, pInfo);
   }
@@ -1193,7 +1190,6 @@ static void btreeParseCellPtrIndex(
     pInfo->nSize = nPayload + (u16)(pIter - pCell);
     if( pInfo->nSize<4 ) pInfo->nSize = 4;
     pInfo->nLocal = (u16)nPayload;
-    pInfo->iOverflow = 0;
   }else{
     btreeParseCellAdjustSizeForOverflow(pPage, pCell, pInfo);
   }
@@ -1309,8 +1305,8 @@ static void ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell, int *pRC){
   if( *pRC ) return;
   assert( pCell!=0 );
   pPage->xParseCell(pPage, pCell, &info);
-  if( info.iOverflow ){
-    Pgno ovfl = get4byte(&pCell[info.iOverflow]);
+  if( info.nLocal<info.nPayload ){
+    Pgno ovfl = get4byte(&pCell[info.nSize-4]);
     ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
   }
 }
@@ -3348,11 +3344,11 @@ static int modifyPagePointer(MemPage *pPage, Pgno iFrom, Pgno iTo, u8 eType){
       if( eType==PTRMAP_OVERFLOW1 ){
         CellInfo info;
         pPage->xParseCell(pPage, pCell, &info);
-        if( info.iOverflow
-         && pCell+info.iOverflow+3<=pPage->aData+pPage->maskPage
-         && iFrom==get4byte(&pCell[info.iOverflow])
+        if( info.nLocal<info.nPayload
+         && pCell+info.nSize-1<=pPage->aData+pPage->maskPage
+         && iFrom==get4byte(pCell+info.nSize-4)
         ){
-          put4byte(&pCell[info.iOverflow], iTo);
+          put4byte(pCell+info.nSize-4, iTo);
           break;
         }
       }else{
@@ -5994,13 +5990,13 @@ static int clearCell(
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
   pPage->xParseCell(pPage, pCell, &info);
   *pnSize = info.nSize;
-  if( info.iOverflow==0 ){
+  if( info.nLocal==info.nPayload ){
     return SQLITE_OK;  /* No overflow pages. Return without doing anything */
   }
-  if( pCell+info.iOverflow+3 > pPage->aData+pPage->maskPage ){
+  if( pCell+info.nSize-1 > pPage->aData+pPage->maskPage ){
     return SQLITE_CORRUPT_BKPT;  /* Cell extends past end of page */
   }
-  ovflPgno = get4byte(&pCell[info.iOverflow]);
+  ovflPgno = get4byte(pCell + info.nSize - 4);
   assert( pBt->usableSize > 4 );
   ovflPageSize = pBt->usableSize - 4;
   nOvfl = (info.nPayload - info.nLocal + ovflPageSize - 1)/ovflPageSize;
@@ -6149,7 +6145,6 @@ static int fillInCell(
     assert( info.nKey==nKey );
     assert( *pnSize == info.nSize );
     assert( spaceLeft == info.nLocal );
-    assert( pPrior == &pCell[info.iOverflow] );
   }
 #endif
 
@@ -6859,8 +6854,8 @@ static int ptrmapCheckPages(MemPage **apPage, int nPage){
      
       z = findCell(pPage, j);
       pPage->xParseCell(pPage, z, &info);
-      if( info.iOverflow ){
-        Pgno ovfl = get4byte(&z[info.iOverflow]);
+      if( info.nLocal<info.nPayload ){
+        Pgno ovfl = get4byte(&z[info.nSize-4]);
         ptrmapGet(pBt, ovfl, &e, &n);
         assert( n==pPage->pgno && e==PTRMAP_OVERFLOW1 );
       }
@@ -9166,9 +9161,9 @@ static int checkTreePage(
     if( info.nPayload>info.nLocal ){
       int nPage;       /* Number of pages on the overflow chain */
       Pgno pgnoOvfl;   /* First page of the overflow chain */
-      assert( pc + info.iOverflow <= usableSize );
+      assert( pc + info.nSize - 4 <= usableSize );
       nPage = (info.nPayload - info.nLocal + usableSize - 5)/(usableSize - 4);
-      pgnoOvfl = get4byte(&pCell[info.iOverflow]);
+      pgnoOvfl = get4byte(&pCell[info.nSize - 4]);
 #ifndef SQLITE_OMIT_AUTOVACUUM
       if( pBt->autoVacuum ){
         checkPtrmap(pCheck, pgnoOvfl, PTRMAP_OVERFLOW1, iPage);

src/btreeInt.h

@@ -470,7 +470,6 @@ struct CellInfo {
   u8 *pPayload;  /* Pointer to the start of payload */
   u32 nPayload;  /* Bytes of payload */
   u16 nLocal;    /* Amount of payload held locally, not on overflow */
-  u16 iOverflow; /* Offset to overflow page number.  Zero if no overflow */
   u16 nSize;     /* Size of the cell content on the main b-tree page */
 };