From 840cd4ce4ac8c781e7d35db2ed86d575a42c37e7 Mon Sep 17 00:00:00 2001
From: Anssi Hannula <anssi@xbmc.org>
Date: Wed, 16 May 2012 00:14:49 +0300
Subject: [PATCH] fixed: CRarFile::Read() returning wrong data after some seek
 patterns

Certain seek patterns on a file inside a non-compressed rar file can
cause CmdExtract::UnstoreFile() to think that the destination buffer has
been filled (as DestUnpSize counter, originally set to the file size,
reaches zero).

However, counting written bytes using DestUnpSize doesn't make sense for
the UnpackToMemory codepath used for non-compressed rar files, as there
can be seeks which can eventually cause more data to be read than what
the actual file size was. The actual output buffer is internally handled
by ComprDataIO.

The check in UnstoreFile() will result in not all data being written to
the destination buffer, causing CRarFile::Read() to return old stale
data.

Fix that by dropping the unnecessary DestUnpSize handling in
UnpackToMemory codepath of CmdExtract::UnstoreFile().
---
 lib/UnrarXLib/extract.cpp | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/lib/UnrarXLib/extract.cpp b/lib/UnrarXLib/extract.cpp
index da608572de055..ea9b8f9257fb4 100644
--- a/lib/UnrarXLib/extract.cpp
+++ b/lib/UnrarXLib/extract.cpp
@@ -859,10 +859,7 @@ void CmdExtract::UnstoreFile(ComprDataIO &DataIO,Int64 DestUnpSize)
       }
       if (Code > 0)
       {
-        Code=Code<DestUnpSize ? Code:int64to32(DestUnpSize);
         DataIO.UnpWrite(&Buffer[0],Code);
-        if (DestUnpSize>=0)
-          DestUnpSize-=Code;
       }
       else 
       {