Update zopfli

Author: JayXon

lib/zopfli/cache.c

@@ -34,7 +34,7 @@ void ZopfliInitCache(size_t blocksize, ZopfliLongestMatchCache* lmc) {
   if(lmc->sublen == NULL) {
     fprintf(stderr,
         "Error: Out of memory. Tried allocating %lu bytes of memory.\n",
-        ZOPFLI_CACHE_LENGTH * 3 * blocksize);
+        (unsigned long)ZOPFLI_CACHE_LENGTH * 3 * blocksize);
     exit (EXIT_FAILURE);
   }
 

lib/zopfli/squeeze.c

@@ -205,6 +205,7 @@ static double GetBestLengths(ZopfliBlockState *s,
   double* literals; /*Cost of a literal*/
   double litlentable[259]; /*Cost of the length bits of a match*/
   double disttable[30]; /*Cost of the distance bits of a match*/
+  double litstack[256];
   if(costcontext){
     literals = costcontext->ll_symbols;
     for (i = 3; i < 259; i++){
@@ -215,7 +216,6 @@ static double GetBestLengths(ZopfliBlockState *s,
     }
   }
   else{
-    double litstack[256];
     literals = litstack;
     for (i = 0; i < 256; i++){
       literals[i] = 8 + (i > 143);

lib/zopflipng/lodepng/lodepng_util.cpp

@@ -1151,7 +1151,7 @@ unsigned convertToXYZ(float* out, float whitepoint[3], const unsigned char* in,
     use_icc = validateICC(&icc);
   }
 
-  data = (unsigned char*)lodepng_malloc(w * h * (bit16 ? 8 : 4));
+  data = (unsigned char*)lodepng_malloc((size_t)w * (size_t)h * (bit16 ? 8 : 4));
   error = lodepng_convert(data, in, &tempmode, mode_in, w, h);
   if(error) goto cleanup;
 

lib/zopflipng/zopflipng_lib.cc

@@ -35,6 +35,7 @@ ZopfliPNGOptions::ZopfliPNGOptions()
   , lossy_transparent(false)
   , lossy_8bit(false)
   , auto_filter_strategy(true)
+  , keep_colortype(false)
   , use_zopfli(true)
   , num_iterations(15)
   , num_iterations_large(5)
@@ -379,7 +380,7 @@ int ZopfliPNGOptimize(const std::vector<unsigned char>& origpng,
   lodepng::State inputstate;
   error = lodepng::decode(image, w, h, inputstate, origpng);
 
-  bool keep_colortype = false;
+  bool keep_colortype = png_options.keep_colortype;
 
   if (!png_options.keepchunks.empty()) {
     // If the user wants to keep the non-essential chunks bKGD or sBIT, the
@@ -391,10 +392,12 @@ int ZopfliPNGOptimize(const std::vector<unsigned char>& origpng,
     // possible.
     std::set<std::string> keepchunks;
     ChunksToKeep(origpng, png_options.keepchunks, &keepchunks);
-    keep_colortype = keepchunks.count("bKGD") || keepchunks.count("sBIT");
-    if (keep_colortype && verbose) {
-      printf("Forced to keep original color type due to keeping bKGD or sBIT"
-             " chunk.\n");
+    if (keepchunks.count("bKGD") || keepchunks.count("sBIT")) {
+      if (!keep_colortype && verbose) {
+        printf("Forced to keep original color type due to keeping bKGD or sBIT"
+               " chunk.\n");
+      }
+      keep_colortype = true;
     }
   }
 

lib/zopflipng/zopflipng_lib.h

@@ -105,6 +105,16 @@ struct ZopfliPNGOptions {
   // Automatically choose filter strategy using less good compression
   bool auto_filter_strategy;
 
+  // Keep original color type (RGB, RGBA, gray, gray+alpha or palette) and bit
+  // depth of the PNG.
+  // This results in a loss of compression opportunities, e.g. it will no
+  // longer convert a 4-channel RGBA image to 2-channel gray+alpha if the image
+  // only had translucent gray pixels.
+  // May be useful if a device does not support decoding PNGs of a particular
+  // color type.
+  // Default value: false.
+  bool keep_colortype;
+
   // PNG chunks to keep
   // chunks to literally copy over from the original PNG to the resulting one
   std::vector<std::string> keepchunks;