From 8c2bbb620b2edde8a00e8020163a1800eb2c3c9d Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Fri, 10 Jul 2009 02:52:20 +0000
Subject: [PATCH] Simplifications to the PRAGMA integrity_check logic in
 btree.c. (CVS 6873)

FossilOrigin-Name: 440c573c7e2a22f9a67a9571883e205fbadb7c11
---
 manifest      | 12 ++++++------
 manifest.uuid |  2 +-
 src/btree.c   | 31 +++++++++++++++----------------
 3 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/manifest b/manifest
index f84695654f..cbf62e1d71 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\stwo\sfaulty\sassert()\sstatements\sbtree.\s\s(It\swas\spossible\sfor\sthe\sassertions\nto\sbe\sfalse\sgiven\sa\scorrupt\sdatabase\sfile\sas\sinput.)\s(CVS\s6872)
-D 2009-07-09T13:25:32
+C Simplifications\sto\sthe\sPRAGMA\sintegrity_check\slogic\sin\sbtree.c.\s(CVS\s6873)
+D 2009-07-10T02:52:21
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in df9359da7a726ccb67a45db905c5447d5c00c6ef
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -106,7 +106,7 @@ F src/auth.c 802a9439dfa0b8c208b10055cba400e82ef18025
 F src/backup.c 6f1c2d9862c8a3feb7739dfcca02c1f5352e37f3
 F src/bitvec.c 0ef0651714728055d43de7a4cdd95e703fac0119
 F src/btmutex.c 9b899c0d8df3bd68f527b0afe03088321b696d3c
-F src/btree.c 0c58f7879b6439d2acd5c37b19c754873ffb9e5e
+F src/btree.c 90b5fbf40b9f0294b23ebec71a374cf32e9ca829
 F src/btree.h e53a10fd31d16c60a86f03c9467a6f470aa3683b
 F src/btreeInt.h a568bf057aa249eb06fd31358b4393a5ac88c118
 F src/build.c 867028ee9f63f7bc8eb8d4a720bb98cf9b9a12b4
@@ -740,7 +740,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P 45efb78a8a1e01a0154153b10469bb34d6d129eb
-R 312eb19d05ae6f242619e437dda1112d
+P 9403f04dfdabdd2ba9adb1a91ca9b400cf4ca6b3
+R f5584a1b216a472f2389b4db4fb67036
 U drh
-Z a56b6692cd4d8a5d3fbce96abbee444b
+Z edc8374917110976eef49eaed71b43e7
diff --git a/manifest.uuid b/manifest.uuid
index 5b3a77549a..90e9b7eb6f 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-9403f04dfdabdd2ba9adb1a91ca9b400cf4ca6b3
\ No newline at end of file
+440c573c7e2a22f9a67a9571883e205fbadb7c11
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index fb8038748a..9560703007 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.672 2009/07/09 13:25:32 drh Exp $
+** $Id: btree.c,v 1.673 2009/07/10 02:52:21 drh Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
@@ -7389,7 +7389,7 @@ static int checkTreePage(
       int pc = get2byte(&data[cellStart+i*2]);
       u16 size = 1024;
       int j;
-      if( pc<=usableSize ){
+      if( pc<=usableSize-4 ){
         size = cellSizePtr(pPage, &data[pc]);
       }
       if( (pc+size-1)>=usableSize || pc<0 ){
@@ -7399,17 +7399,17 @@ static int checkTreePage(
         for(j=pc+size-1; j>=pc; j--) hit[j]++;
       }
     }
-    for(cnt=0, i=get2byte(&data[hdr+1]); i>0 && i<usableSize && cnt<10000; 
-           cnt++){
-      int size = get2byte(&data[i+2]);
-      int j;
-      if( (i+size-1)>=usableSize || i<0 ){
-        checkAppendMsg(pCheck, 0,  
-            "Corruption detected in cell %d on page %d",i,iPage,0);
-      }else{
-        for(j=i+size-1; j>=i; j--) hit[j]++;
-      }
-      i = get2byte(&data[i]);
+    i = get2byte(&data[hdr+1]);
+    while( i>0 ){
+      int size, j;
+      assert( i<=usableSize-4 );     /* Enforced by btreeInitPage() */
+      size = get2byte(&data[i+2]);
+      assert( i+size<=usableSize );  /* Enforced by btreeInitPage() */
+      for(j=i+size-1; j>=i; j--) hit[j]++;
+      j = get2byte(&data[i]);
+      assert( j==0 || j>i+size );  /* Enforced by btreeInitPage() */
+      assert( j<=usableSize-4 );   /* Enforced by btreeInitPage() */
+      i = j;
     }
     for(i=cnt=0; i<usableSize; i++){
       if( hit[i]==0 ){
@@ -7422,13 +7422,12 @@ static int checkTreePage(
     }
     if( cnt!=data[hdr+7] ){
       checkAppendMsg(pCheck, 0, 
-          "Fragmented space is %d byte reported as %d on page %d",
+          "Fragmentation of %d bytes reported as %d on page %d",
           cnt, data[hdr+7], iPage);
     }
   }
 check_page_abort:
-  if (hit) sqlite3PageFree(hit);
-
+  sqlite3PageFree(hit);
   releasePage(pPage);
   return depth+1;
 }