fixed png bytebuffer: needed to memset png struct to zeros

build/make.linux64.so.py

@@ -19,7 +19,7 @@ cc = "gcc" #compiler
 # -fvisibility=hidden -- stripping symbols to avoid namespace pollution doesn't seem to work on Linux
 cflags = "-fPIC -O3 -DEXPORT_AMSCIMGLIB4"
 libraries = "-l{} -ljpeg -lpng -lz -lm".format(libname)
-libdirs = "-L{} -L{}/lib -L{}/lib".format(builddir,commondir,depdir)
+libdirs = "-L{} -L{}/lib -L{}/lib".format(builddir,depdir,commondir)
 linkerflags = "-shared -Wl,-rpath=. -Wl,--out-implib={}/lib{}.a".format(builddir,libname)
 srcexts = [".c",".cpp"]
 binsrc = ["main.c","main.cpp"] #ignore these files when compiling the static library

include/amscimglib4/amscimglib4.h

@@ -119,7 +119,7 @@ AMSCIMGLIB4_API void amscimglib4_readimage_jpeg(const char *fname, amscimglib4_i
 AMSCIMGLIB4_API void amscimglib4_writeimage_jpeg(const char *fname, amscimglib4_image *img, int quality);
 
 //Read and write PNG files from memory buffers
-AMSCIMGLIB4_API int amscimglib4_pngbytebuffer_to_img(amscimglib4_image *img, unsigned char *bytebuffer, long nbytes);
+AMSCIMGLIB4_API int amscimglib4_pngbytebuffer_to_img(amscimglib4_image *img, const unsigned char *bytebuffer, long nbytes);
 
 //returns length required for a bytebuffer to store img as a png
 AMSCIMGLIB4_API long amscimglib4_pngbytebufferlen(amscimglib4_image *img);

src/amscimglib4/amscimglib4_png.c

@@ -147,7 +147,7 @@ AMSCIMGLIB4_API void amscimglib4_writeimage_png(const char *fname, amscimglib4_i
 
 
 //Reads and writes png data to and from a bytebuffer in memory (for compression)
-AMSCIMGLIB4_API int amscimglib4_pngbytebuffer_to_img(amscimglib4_image *img, unsigned char *bytebuffer, long nbytes)
+AMSCIMGLIB4_API int amscimglib4_pngbytebuffer_to_img(amscimglib4_image *img, const unsigned char *bytebuffer, long nbytes)
 {
   int ret = amscimglib4_success;
   int res;
@@ -227,6 +227,7 @@ AMSCIMGLIB4_API long amscimglib4_pngbytebufferlen(amscimglib4_image *img)
 
   png_image pngimage;
 
+  memset(&pngimage,0,sizeof(pngimage)); //fills memory with zeros
   pngimage.version = PNG_IMAGE_VERSION;
   pngimage.format = PNG_FORMAT_RGBA;
   pngimage.width = img->sizex;
@@ -260,6 +261,7 @@ AMSCIMGLIB4_API int amscimglib4_pngbytebuffer_from_img(amscimglib4_image *img, u
   png_image pngimage;
   png_alloc_size_t bufflen2 = bufflen;
 
+  memset(&pngimage,0,sizeof(pngimage)); //fills memory with zeros
   pngimage.version = PNG_IMAGE_VERSION;
   pngimage.format = PNG_FORMAT_RGBA;
   pngimage.width = img->sizex;