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/SBaseFileTable.cpp | 43 ++++++++++++++++++++++++++++++-------------
 1 file changed, 30 insertions(+), 13 deletions(-)

(limited to 'src/SBaseFileTable.cpp')

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)
-- 
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