From 689f34c5313bdc8382ba29789c96b13ca953bb96 Mon Sep 17 00:00:00 2001
From: Kimmo Varis <kimmov@gmail.com>
Date: Tue, 25 Mar 2003 18:08:05 +0000
Subject: [PATCH] PATCH: [ 703069 ] Fix undo crash

---
 Src/editlib/ccrystaltextbuffer.cpp | 40 +++++++++++++++++++++++++++++++-------
 Src/readme.txt                     |  2 ++
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/Src/editlib/ccrystaltextbuffer.cpp b/Src/editlib/ccrystaltextbuffer.cpp
index 43f794968..4fc52fdbc 100644
--- a/Src/editlib/ccrystaltextbuffer.cpp
+++ b/Src/editlib/ccrystaltextbuffer.cpp
@@ -1123,12 +1123,16 @@ Undo (CPoint & ptCursorPos)
 {
   ASSERT (CanUndo ());
   ASSERT ((m_aUndoBuf[0].m_dwFlags & UNDO_BEGINGROUP) != 0);
+  BOOL found = TRUE;
+  int tmpPos = m_nUndoPosition;
+
   for (;;)
     {
-      m_nUndoPosition--;
-      const SUndoRecord & ur = m_aUndoBuf[m_nUndoPosition];
+      tmpPos--;;
+      const SUndoRecord & ur = m_aUndoBuf[tmpPos];
       if (ur.m_dwFlags & UNDO_INSERT)
         {
+#if 0 //original code
 #ifdef _ADVANCED_BUGCHECK
           //  Try to ensure that we undoing correctly...
           //  Just compare the text as it was before Undo operation
@@ -1136,8 +1140,28 @@ Undo (CPoint & ptCursorPos)
           GetText (ur.m_ptStartPos.y, ur.m_ptStartPos.x, ur.m_ptEndPos.y, ur.m_ptEndPos.x, text);
           ASSERT (lstrcmp (text, ur.GetText ()) == 0);
 #endif
-          VERIFY (InternalDeleteText (NULL, ur.m_ptStartPos.y, ur.m_ptStartPos.x, ur.m_ptEndPos.y, ur.m_ptEndPos.x));
-          ptCursorPos = ur.m_ptStartPos;
+#endif // original code
+
+          // WINMERGE -- Check that text in undo buffer matches text in
+          // file buffer.  If not, then rescan() has moved lines and undo
+          // is skipped.
+          CString text;
+          if ((ur.m_ptStartPos.y < m_aLines.GetSize ()) &&
+              (ur.m_ptStartPos.x <= m_aLines[ur.m_ptStartPos.y].m_nLength) &&
+              (ur.m_ptEndPos.y < m_aLines.GetSize ()) &&
+              (ur.m_ptEndPos.x <= m_aLines[ur.m_ptEndPos.y].m_nLength))
+            {
+              GetText (ur.m_ptStartPos.y, ur.m_ptStartPos.x, ur.m_ptEndPos.y, ur.m_ptEndPos.x, text);
+              if (_tcscmp(text, ur.GetText()) == 0)
+                {
+                   VERIFY (InternalDeleteText (NULL, ur.m_ptStartPos.y, ur.m_ptStartPos.x, ur.m_ptEndPos.y, ur.m_ptEndPos.x));
+                      ptCursorPos = ur.m_ptStartPos;
+                }
+              else
+                   found = FALSE;
+            }
+          else
+              found = FALSE;
         }
       else
         {
@@ -1152,11 +1176,13 @@ Undo (CPoint & ptCursorPos)
       if (ur.m_dwFlags & UNDO_BEGINGROUP)
         break;
     }
-  if (m_bModified && m_nSyncPosition == m_nUndoPosition)
+  if (m_bModified && m_nSyncPosition == tmpPos)
     SetModified (FALSE);
-  if (!m_bModified && m_nSyncPosition != m_nUndoPosition)
+  if (!m_bModified && m_nSyncPosition != tmpPos)
     SetModified (TRUE);
-  return TRUE;
+  if (found)
+    m_nUndoPosition = tmpPos;
+  return found;
 }
 
 BOOL CCrystalTextBuffer::
diff --git a/Src/readme.txt b/Src/readme.txt
index aff05e66b..9e61e0229 100644
--- a/Src/readme.txt
+++ b/Src/readme.txt
@@ -1,6 +1,8 @@
 2003-03-25 Kimmo
  PATCH: [ 708893 ] Don't ask to save file compare
   WinMerge: MergeDoc.h MergeDoc.cpp
+ PATCH: [ 703069 ] Fix undo crash
+  editlib: crystaltextbuffer.cpp
 
 2003-03-23 Perry
  PATCH: [ 706006 ] Suppress Rescan during Merge
-- 
2.11.0