More speed improvements to btree. (CVS 1384)

FossilOrigin-Name: aab4b794b4238bad5c4a6aee7d4443732921127d

manifest

@@ -1,5 +1,5 @@
-C Allocates\sVDBE\scursors\sone\sby\sone\sin\sseparate\smemory\sso\sthat\spointers\sto\ncursors\scan\spersist\sthrough\sa\srealloc().\s(CVS\s1383)
-D 2004-05-14T21:59:40
+C More\sspeed\simprovements\sto\sbtree.\s(CVS\s1384)
+D 2004-05-15T00:29:24
 F Makefile.in ab7b0d5118e2da97bac66be8684a1034e3500f5a
 F Makefile.linux-gcc b86a99c493a5bfb402d1d9178dcdc4bd4b32f906
 F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
@@ -23,7 +23,7 @@ F sqlite.def fc4f5734786fe4743cfe2aa98eb2da4b089edb5f
 F sqlite.pc.in 30552343140c53304c2a658c080fbe810cd09ca2
 F src/attach.c c315c58cb16fd6e913b3bfa6412aedecb4567fa5
 F src/auth.c 5c2f0bea4729c98c2be3b69d6b466fc51448fe79
-F src/btree.c 731695f701be37c20146b0aaaf415135f01b6deb
+F src/btree.c 05aefd3eec56690d9731bf090203b57d8ae4bf19
 F src/btree.h 6f51ad0ffebfba71295fcacdbe86007512200050
 F src/btree_rb.c 9d7973e266ee6f9c61ce592f68742ce9cd5b10e5
 F src/build.c e93f443a20eab57ffb77ff6244b1e09a1f7d9390
@@ -191,7 +191,7 @@ F www/sqlite.tcl 3c83b08cf9f18aa2d69453ff441a36c40e431604
 F www/tclsqlite.tcl b9271d44dcf147a93c98f8ecf28c927307abd6da
 F www/vdbe.tcl 9b9095d4495f37697fd1935d10e14c6015e80aa1
 F www/whentouse.tcl a8335bce47cc2fddb07f19052cb0cb4d9129a8e4
-P 8d9eab178f285415775060369f372a88c7091f9f
-R b51b67250edc5f732aa65343a7a205f1
+P d8bacc16801606176fe8639b2f55b4584ad549df
+R d43b2b97f5dc394b60a54b98133aa83a
 U drh
-Z 23e87bbd07c6c07486d74ecaf3cab33d
+Z 06eabac28a7b451889010e7a03f02723

manifest.uuid

@@ -1 +1 @@
-d8bacc16801606176fe8639b2f55b4584ad549df
+aab4b794b4238bad5c4a6aee7d4443732921127d

src/btree.c

@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.139 2004/05/14 21:12:23 drh Exp $
+** $Id: btree.c,v 1.140 2004/05/15 00:29:24 drh Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** For a detailed discussion of BTrees, refer to
@@ -709,7 +709,8 @@ static int initPage(
   int c, pc, i, hdr;
   unsigned char *data;
   int usableSize;
-  /* int sumCell = 0;       // Total size of all cells */
+  int nCell, nFree;
+  u8 *aCell[MX_PAGE_SIZE/2];
 
 
   assert( pPage->pBt!=0 );
@@ -739,43 +740,37 @@ static int initPage(
   usableSize = pPage->pBt->usableSize;
 
   /* Initialize the cell count and cell pointers */
+  i = 0;
   pc = get2byte(&data[hdr+3]);
+  nCell = 0;
   while( pc>0 ){
     if( pc>=usableSize ) return SQLITE_CORRUPT;
-    if( pPage->nCell>usableSize ) return SQLITE_CORRUPT;
-    pPage->nCell++;
+    if( nCell>sizeof(aCell)/sizeof(aCell[0]) ) return SQLITE_CORRUPT;
+    aCell[nCell++] = &data[pc];
     pc = get2byte(&data[pc]);
   }
-  if( resizeCellArray(pPage, pPage->nCell) ){
+  if( resizeCellArray(pPage, nCell) ){
     return SQLITE_NOMEM;
   }
-  pc = get2byte(&data[hdr+3]);
-  for(i=0; pc>0; i++){
-    pPage->aCell[i] = &data[pc];
-    /* sumCell += cellSize(pPage, &data[pc]); */
-    pc = get2byte(&data[pc]);
-  }
+  pPage->nCell = nCell;
+  memcpy(pPage->aCell, aCell, nCell*sizeof(aCell[0]));
 
   /* Compute the total free space on the page */
-  pPage->nFree = data[hdr+5];
   pc = get2byte(&data[hdr+1]);
+  nFree = data[hdr+5];
+  i = 0;
   while( pc>0 ){
     int next, size;
     if( pc>=usableSize ) return SQLITE_CORRUPT;
+    if( i++>MX_PAGE_SIZE ) return SQLITE_CORRUPT;
     next = get2byte(&data[pc]);
     size = get2byte(&data[pc+2]);
     if( next>0 && next<=pc+size+3 ) return SQLITE_CORRUPT;
-    pPage->nFree += size;
+    nFree += size;
     pc = next;
   }
-  if( pPage->nFree>=usableSize ) return SQLITE_CORRUPT;
-
-  /* Sanity check:  Cells and freespace and header must sum to the size
-  ** a page.
-  if( sumCell+pPage->nFree+hdr+10-pPage->leaf*4 != usableSize ){
-    return SQLITE_CORRUPT;
-  }
-  */
+  pPage->nFree = nFree;
+  if( nFree>=usableSize ) return SQLITE_CORRUPT;
 
   pPage->isInit = 1;
   pageIntegrity(pPage);