From 30e7e18fa2d1a462be260d695dab0dcf5b956550 Mon Sep 17 00:00:00 2001
From: Alec Miller <alecmiller@yahoo.com>
Date: Wed, 5 Jun 2024 09:28:33 -0700
Subject: [PATCH] kram - re-enable libCompression, but disable miniz and
 libCompression on lodepng

Too many failures of the src test suite trying to switch to miniz or libCompression as a custom ziib.
  May need to supply custom_inflate/deflate instead.
  iccp block on inter-a.png breaks miniZ.
Did managed to advance +2, size -2 to get libCompression to gen similar decompress to miniZ.
---
 libkram/kram/KTXImage.cpp      |  3 +--
 libkram/kram/Kram.cpp          | 18 ++++++++++++------
 libkram/kram/KramZipHelper.cpp |  3 +--
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/libkram/kram/KTXImage.cpp b/libkram/kram/KTXImage.cpp
index aee2287..047dbde 100644
--- a/libkram/kram/KTXImage.cpp
+++ b/libkram/kram/KTXImage.cpp
@@ -16,9 +16,8 @@
 // for zstd decompress
 #include "zstd.h"
 
-// Don't trust this see use in Kram.cpp with lodepng
 #ifndef USE_LIBCOMPRESSION
-#define USE_LIBCOMPRESSION 0 // (KRAM_MAC || KRAM_IOS)
+#define USE_LIBCOMPRESSION (KRAM_MAC || KRAM_IOS)
 #endif
 
 #if USE_LIBCOMPRESSION
diff --git a/libkram/kram/Kram.cpp b/libkram/kram/Kram.cpp
index cee9db7..2951a5b 100644
--- a/libkram/kram/Kram.cpp
+++ b/libkram/kram/Kram.cpp
@@ -27,8 +27,6 @@
 #include "lodepng.h"
 #include "miniz.h"
 
-// This doesn't work returns 121 for a 16K decode
-// Just open the src directory
 #ifndef USE_LIBCOMPRESSION
 #define USE_LIBCOMPRESSION 0 // (KRAM_MAC || KRAM_IOS)
 #endif
@@ -62,7 +60,11 @@ namespace kram {
 
 using namespace NAMESPACE_STL;
 
-static bool useMiniZ = true;
+// This fails with libCompression (see inter-a.png)
+// and with miniZ for the ICCP block (see inter-a.png)
+// lodepng passes 16K to the custom zlib decompress, but
+// the data read isn't that big.
+static bool useMiniZ = false;
 
 template <typename T>
 void releaseVector(vector<T>& v)
@@ -423,12 +425,16 @@ unsigned LodepngDecompressUsingMiniz(
     KASSERT(*dstDataSize != 0);
     
 #if USE_LIBCOMPRESSION
-    // This call can't be replaced since lodepng doesn't pass size
-    // And it doesn't take a nullable dstData?
+    // this returns 121 dstSize instead of 16448 on 126 srcSize.  
+    // Open src dir to see this.  Have to advance by 2 to fix this.
+    if (srcDataSize <= 2) {
+        return MZ_DATA_ERROR;
+    }
+    
     char scratchBuffer[compression_decode_scratch_buffer_size(COMPRESSION_ZLIB)];
     size_t bytesDecoded = compression_decode_buffer(
          (uint8_t*)*dstData, *dstDataSize,
-         (const uint8_t*)srcData, srcDataSize,
+         (const uint8_t*)srcData + 2, srcDataSize - 2,
         scratchBuffer, // scratch-buffer that could speed up to pass
          COMPRESSION_ZLIB);
     
diff --git a/libkram/kram/KramZipHelper.cpp b/libkram/kram/KramZipHelper.cpp
index bb2a427..f02d51f 100644
--- a/libkram/kram/KramZipHelper.cpp
+++ b/libkram/kram/KramZipHelper.cpp
@@ -9,9 +9,8 @@
 // test for perf of this compared to one in miniz also see 
 // comments about faster algs.
 // libcompress can only encode lvl 5, but here it's only decompress.
-// Don't trust this.
 #ifndef USE_LIBCOMPRESSION
-#define USE_LIBCOMPRESSION 0 // (KRAM_MAC || KRAM_IOS)
+#define USE_LIBCOMPRESSION (KRAM_MAC || KRAM_IOS)
 #endif
 
 #if USE_LIBCOMPRESSION