From 909ff807e78b0b92afffaf0d5ed7149982d8ac33 Mon Sep 17 00:00:00 2001
From: Ladislav Zezula <zezula@volny.cz>
Date: Sat, 30 Dec 2023 08:59:09 +0100
Subject: Regression tests passed

---
 src/SBaseCommon.cpp        |  2 +-
 src/SBaseFileTable.cpp     | 43 ++++++++++++++++++++++++++++++-------------
 src/SFileCreateArchive.cpp |  3 +++
 src/SFileOpenArchive.cpp   |  5 +++++
 src/StormCommon.h          |  1 +
 src/StormLib.h             |  1 +
 6 files changed, 41 insertions(+), 14 deletions(-)

(limited to 'src')

diff --git a/src/SBaseCommon.cpp b/src/SBaseCommon.cpp
index 4fc473a..7415583 100644
--- a/src/SBaseCommon.cpp
+++ b/src/SBaseCommon.cpp
@@ -15,7 +15,7 @@
 #include "StormLib.h"
 #include "StormCommon.h"
 
-char StormLibCopyright[] = "StormLib v " STORMLIB_VERSION_STRING " Copyright Ladislav Zezula 1998-2014";
+char StormLibCopyright[] = "StormLib v " STORMLIB_VERSION_STRING " Copyright Ladislav Zezula 1998-2023";
 
 //-----------------------------------------------------------------------------
 // Local variables
diff --git a/src/SBaseFileTable.cpp b/src/SBaseFileTable.cpp
index a53d6a6..ca14693 100644
--- a/src/SBaseFileTable.cpp
+++ b/src/SBaseFileTable.cpp
@@ -385,20 +385,39 @@ static ULONGLONG DetermineArchiveSize_V4(
     return ArchiveSize;
 }
 
-ULONGLONG FileOffsetFromMpqOffset(TMPQArchive * ha, ULONGLONG MpqOffset)
+ULONGLONG GetFileOffsetMask(TMPQArchive * ha)
 {
+    ULONGLONG FileOffsetMask = (ULONGLONG)(-1);
+
+    // Sanity checks
+    assert(ha != NULL);
+    assert(ha->pHeader != NULL);
+
+    // MPQs of format 1 are 32-bit only
     if(ha->pHeader->wFormatVersion == MPQ_FORMAT_VERSION_1)
-    {
-        // For MPQ archive v1, any file offset is only 32-bit
-        return (ULONGLONG)((DWORD)ha->MpqPos + (DWORD)MpqOffset);
-    }
-    else
-    {
-        // For MPQ archive v2+, file offsets are full 64-bit
-        return ha->MpqPos + MpqOffset;
-    }
+        FileOffsetMask = (ULONGLONG)(DWORD)(-1);
+    return FileOffsetMask;
 }
 
+ULONGLONG FileOffsetFromMpqOffset(TMPQArchive * ha, ULONGLONG MpqOffset)
+{
+    return (ha->MpqPos + MpqOffset) & ha->FileOffsetMask;
+}
+
+//ULONGLONG FileOffsetFromMpqOffset(TMPQArchive * ha, ULONGLONG MpqOffset)
+//{
+//    if(ha->pHeader->wFormatVersion == MPQ_FORMAT_VERSION_1)
+//    {
+//        // For MPQ archive v1, any file offset is only 32-bit
+//        return (ULONGLONG)((DWORD)ha->MpqPos + (DWORD)MpqOffset);
+//    }
+//    else
+//    {
+//        // For MPQ archive v2+, file offsets are full 64-bit
+//        return ha->MpqPos + MpqOffset;
+//    }
+//}
+
 ULONGLONG CalculateRawSectorOffset(
     TMPQFile * hf,
     DWORD dwSectorOffset)
@@ -418,9 +437,7 @@ ULONGLONG CalculateRawSectorOffset(
     // For MPQs version 1.0, the offset is purely 32-bit
     //
 
-    RawFilePos = hf->RawFilePos + dwSectorOffset;
-    if(hf->ha->pHeader->wFormatVersion == MPQ_FORMAT_VERSION_1)
-        RawFilePos = (DWORD)hf->ha->MpqPos + (DWORD)hf->pFileEntry->ByteOffset + dwSectorOffset;
+    RawFilePos = (hf->RawFilePos + dwSectorOffset) & hf->ha->FileOffsetMask;
 
     // We also have to add patch header size, if patch header is present
     if(hf->pPatchInfo != NULL)
diff --git a/src/SFileCreateArchive.cpp b/src/SFileCreateArchive.cpp
index c0ea367..bae3dcc 100644
--- a/src/SFileCreateArchive.cpp
+++ b/src/SFileCreateArchive.cpp
@@ -238,6 +238,9 @@ bool WINAPI SFileCreateArchive2(const TCHAR * szMpqName, PSFILE_CREATE_MPQ pCrea
         pHeader->dwBlockTablePos  = pHeader->dwHashTablePos + dwHashTableSize * sizeof(TMPQHash);
         pHeader->dwBlockTableSize = dwBlockTableSize;
 
+        // Set the mask for MPQ byte offset
+        ha->FileOffsetMask = GetFileOffsetMask(ha);
+        
         // For MPQs version 4 and higher, we set the size of raw data block
         // for calculating MD5
         if(pCreateInfo->dwMpqVersion >= MPQ_FORMAT_VERSION_4)
diff --git a/src/SFileOpenArchive.cpp b/src/SFileOpenArchive.cpp
index baad848..4b2d3b4 100644
--- a/src/SFileOpenArchive.cpp
+++ b/src/SFileOpenArchive.cpp
@@ -463,6 +463,11 @@ bool WINAPI SFileOpenArchive(
         if(IsStarcraftBetaArchive(ha->pHeader))
             ha->dwFlags |= MPQ_FLAG_STARCRAFT_BETA;
 
+        // Set the mask for the file offset. In MPQs version 1,
+        // all offsets are 32-bit and overflow is allowed.
+        // For MPQs v2+, file offset if 64-bit.
+        ha->FileOffsetMask = GetFileOffsetMask(ha);
+
         // Maps from StarCraft and Warcraft III need special treatment
         switch(MapType)
         {
diff --git a/src/StormCommon.h b/src/StormCommon.h
index 34077fd..c73543d 100644
--- a/src/StormCommon.h
+++ b/src/StormCommon.h
@@ -251,6 +251,7 @@ TMPQFile * IsValidFileHandle(HANDLE hFile);
 //-----------------------------------------------------------------------------
 // Support for MPQ file tables
 
+ULONGLONG GetFileOffsetMask(TMPQArchive * ha);
 ULONGLONG FileOffsetFromMpqOffset(TMPQArchive * ha, ULONGLONG MpqOffset);
 ULONGLONG CalculateRawSectorOffset(TMPQFile * hf, DWORD dwSectorOffset);
 
diff --git a/src/StormLib.h b/src/StormLib.h
index b78f7ef..e211cd8 100644
--- a/src/StormLib.h
+++ b/src/StormLib.h
@@ -830,6 +830,7 @@ typedef struct _TMPQArchive
     ULONGLONG      UserDataPos;                 // Position of user data (relative to the begin of the file)
     ULONGLONG      MpqPos;                      // MPQ header offset (relative to the begin of the file)
     ULONGLONG      FileSize;                    // Size of the file at the moment of file open
+    ULONGLONG      FileOffsetMask;              // 0xFFFFFFFF for MPQ v 1, otherwise 0xFFFFFFFFFFFFFFFFull
 
     struct _TMPQArchive * haPatch;              // Pointer to patch archive, if any
     struct _TMPQArchive * haBase;               // Pointer to base ("previous version") archive, if any
-- 
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