From 6aedb395f4691294d3809f8f84d6539885a31627 Mon Sep 17 00:00:00 2001
From: wp_xxyyzz <wp_xxyyzz@8e941d3f-bd1b-0410-a28a-d453659cc2b4>
Date: Mon, 26 Feb 2018 22:20:06 +0000
Subject: [PATCH] fpspreadsheet: Fix xls reader crashing if comment has record
 sequence OBJ-CONTINUE-TX0-CONTINUE instead of OBJ-TX0-CONTINUE.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@6214 8e941d3f-bd1b-0410-a28a-d453659cc2b4
---
 components/fpspreadsheet/source/common/xlsbiff8.pas | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/components/fpspreadsheet/source/common/xlsbiff8.pas b/components/fpspreadsheet/source/common/xlsbiff8.pas
index ea5a70fb7..f7e5f2a83 100644
--- a/components/fpspreadsheet/source/common/xlsbiff8.pas
+++ b/components/fpspreadsheet/source/common/xlsbiff8.pas
@@ -537,7 +537,7 @@ var
   comment: TBIFF8Comment;
   rtParams: TsRichTextParams;
 begin
-  if FCommentPending then begin
+  if FCommentPending and (FCommentLen > 0) then begin
     commentStr := Utf8Encode(ReadWideString(AStream, FCommentLen, rtParams));
     if commentStr <> '' then
     begin
@@ -605,6 +605,7 @@ begin
           if objType = $19 then begin  // $19 = object is a "comment"
             FCommentPending := true;
             FCommentID := objID;
+            FCommentLen := 0;  // will be determined in following TX0 record
             exit;
           end else
             FCommentPending := false;
@@ -886,6 +887,9 @@ begin
     RecordSize := WordLEToN(AStream.ReadWord);
     PendingRecordSize := RecordSize;
 
+// For debugging to find out in which record a crash happens:
+//    WriteLn(Format('Stream.Pos: %d, RecordType: $%.04x, RecordSize: %d', [AStream.Position-4, RecordType, RecordSize]));
+
     CurStreamPos := AStream.Position;
 
     case RecordType of