Decompile fn_07870 (CGifRes::DecodeGif)

Batch #12438 by Yommy: 0 byte-identical, 1 confirmed by peer review.

- fn_07870 CGifRes::DecodeGif: logic confirmed by peer review

Peer-reviewed-by: KWDev, SapitoSucio, dori, cremane
Accepted without human review: peers confirmed the logic ("same" ahead by at least 3, with 70% of the votes).

Source/Resource/GifLzw.cpp

@@ -1,4 +1,4 @@
-#include "Resource/GifLzw.h"
+#include "Resource/GifResource.h"
 
 #include <cstdlib>
 

Source/Resource/GifResource.cpp

@@ -1,7 +1,6 @@
 #include "Resource/GifResource.h"
 
 #include "File/File.h"
-#include "Resource/GifLzw.h"
 
 #include <algorithm>
 #include <cstring>
@@ -47,8 +46,8 @@ namespace {
 
   // INLINED
   bool IsGifSignature(const void* data) {
-    const auto* bytes = static_cast<const unsigned char*>(data);
-    return bytes[0] == 'G' && bytes[1] == 'I' && bytes[2] == 'F';
+    constexpr char signature[] = {'G', 'I', 'F'};
+    return std::memcmp(data, signature, sizeof(signature)) == 0;
   }
 }
 
@@ -295,7 +294,7 @@ bool CGifRes::DecodeGif(const void* data, int bytes, bool iconOnly) {
       ++cursor;
 
       unsigned char* indices = new unsigned char[descriptor.width * descriptor.height];
-      if (DecodeGifLzw(minimumCodeSize, compressed, compressedBytes, indices) > 0) {
+      if (this->DecodeGifLzw(minimumCodeSize, compressed, compressedBytes, indices) > 0) {
         const unsigned int pixelCount = screenHeight * screenWidth;
         std::uint32_t* pixels = new std::uint32_t[pixelCount];
 

Source/Resource/GifResource.h

@@ -23,6 +23,7 @@ public:
 
   void CreateBlank(int width, int height);
   bool DecodeGif(const void* data, int bytes, bool iconOnly);
+  int DecodeGifLzw(int minimumCodeSize, const unsigned char* input, int inputBytes, unsigned char* output);
 
   /* 0124 */ std::vector<Frame> frames;
   /* 0130 */ std::uint16_t loopCount;