Made load_file function return error if file can't be opened

4 files changed, 25 insertions, 21 deletions

diff --git a/examples/example_decode.c b/examples/example_decode.c
index 1ecec3d..8f6ce39 100644
--- a/examples/example_decode.c
+++ b/examples/example_decode.c
@@ -59,11 +59,11 @@ void decodeTwoSteps(const char* filename)
   unsigned error;

   unsigned char* image;

   unsigned width, height;

-  unsigned char* png;

+  unsigned char* png = 0;

   size_t pngsize;

 

-  lodepng_load_file(&png, &pngsize, filename);

-  error = lodepng_decode32(&image, &width, &height, png, pngsize);

+  error = lodepng_load_file(&png, &pngsize, filename);

+  if(!error) error = lodepng_decode32(&image, &width, &height, png, pngsize);

   if(error) printf("error %u: %s\n", error, lodepng_error_text(error));

 

   free(png);

@@ -82,15 +82,15 @@ void decodeWithState(const char* filename)
   unsigned error;

   unsigned char* image;

   unsigned width, height;

-  unsigned char* png;

+  unsigned char* png = 0;

   size_t pngsize;

   LodePNGState state;

 

   lodepng_state_init(&state);

   /*optionally customize the state*/

 

-  lodepng_load_file(&png, &pngsize, filename);

-  error = lodepng_decode(&image, &width, &height, &state, png, pngsize);

+  error = lodepng_load_file(&png, &pngsize, filename);

+  if(!error) error = lodepng_decode(&image, &width, &height, &state, png, pngsize);

   if(error) printf("error %u: %s\n", error, lodepng_error_text(error));

 

   free(png);

@@ -107,7 +107,7 @@ int main(int argc, char *argv[])
   const char* filename = argc > 1 ? argv[1] : "test.png";

 

   decodeOneStep(filename);

-  

+

   return 0;

 }

 

diff --git a/examples/example_decode.cpp b/examples/example_decode.cpp
index 4eee6b8..76cda6e 100644
--- a/examples/example_decode.cpp
+++ b/examples/example_decode.cpp
@@ -58,8 +58,8 @@ void decodeTwoSteps(const char* filename)
   unsigned width, height;

 

   //load and decode

-  lodepng::load_file(png, filename);

-  unsigned error = lodepng::decode(image, width, height, png);

+  unsigned error = lodepng::load_file(png, filename);

+  if(!error) error = lodepng::decode(image, width, height, png);

 

   //if there's an error, display it

   if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;

@@ -76,8 +76,8 @@ void decodeWithState(const char* filename)
   unsigned width, height;

   lodepng::State state; //optionally customize this one

 

-  lodepng::load_file(png, filename); //load the image file with given filename

-  unsigned error = lodepng::decode(image, width, height, state, png);

+  unsigned error = lodepng::load_file(png, filename); //load the image file with given filename

+  if(!error) error = lodepng::decode(image, width, height, state, png);

 

   //if there's an error, display it

   if(error) std::cout << "decoder error " << error << ": "<< lodepng_error_text(error) << std::endl;

diff --git a/lodepng.cpp b/lodepng.cpp
index a5a5b78..b0d9845 100644
--- a/lodepng.cpp
+++ b/lodepng.cpp
@@ -1,5 +1,5 @@
 /*
-LodePNG version 20151024
+LodePNG version 20151208
 
 Copyright (c) 2005-2015 Lode Vandevenne
 
@@ -42,7 +42,7 @@ Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for
 #pragma warning( disable : 4996 ) /*VS does not like fopen, but fopen_s is not standard C so unusable here*/
 #endif /*_MSC_VER */
 
-const char* LODEPNG_VERSION_STRING = "20151024";
+const char* LODEPNG_VERSION_STRING = "20151208";
 
 /*
 This source file is built up in the following large parts. The code sections
@@ -5873,8 +5873,7 @@ const char* lodepng_error_text(unsigned code)
     case 43: return "bKGD chunk has wrong size for palette image";
     case 44: return "bKGD chunk has wrong size for greyscale image";
     case 45: return "bKGD chunk has wrong size for RGB image";
-    /*the input data is empty, maybe a PNG file doesn't exist or is in the wrong path*/
-    case 48: return "empty input or file doesn't exist";
+    case 48: return "empty input buffer given to decoder. Maybe caused by non-existing file?";
     case 49: return "jumped past memory while generating dynamic huffman tree";
     case 50: return "jumped past memory while generating dynamic huffman tree";
     case 51: return "jumped past memory while inflating huffman block";
@@ -5940,9 +5939,10 @@ namespace lodepng
 {
 
 #ifdef LODEPNG_COMPILE_DISK
-void load_file(std::vector<unsigned char>& buffer, const std::string& filename)
+unsigned load_file(std::vector<unsigned char>& buffer, const std::string& filename)
 {
   std::ifstream file(filename.c_str(), std::ios::in|std::ios::binary|std::ios::ate);
+  if(!file) return 78;
 
   /*get filesize*/
   std::streamsize size = 0;
@@ -5952,6 +5952,8 @@ void load_file(std::vector<unsigned char>& buffer, const std::string& filename)
   /*read contents of the file into the vector*/
   buffer.resize(size_t(size));
   if(size > 0) file.read((char*)(&buffer[0]), size);
+
+  return 0; /* OK */
 }
 
 /*write given buffer to the file, overwriting the file, it doesn't append to it.*/
@@ -6087,7 +6089,8 @@ unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const
                 LodePNGColorType colortype, unsigned bitdepth)
 {
   std::vector<unsigned char> buffer;
-  load_file(buffer, filename);
+  unsigned error = load_file(buffer, filename);
+  if(error) return error;
   return decode(out, w, h, buffer, colortype, bitdepth);
 }
 #endif /* LODEPNG_COMPILE_DECODER */
diff --git a/lodepng.h b/lodepng.h
index 86c24f9..800cd0c 100644
--- a/lodepng.h
+++ b/lodepng.h
@@ -1,5 +1,5 @@
 /*
-LodePNG version 20151024
+LodePNG version 20151208
 
 Copyright (c) 2005-2015 Lode Vandevenne
 
@@ -848,10 +848,10 @@ unsigned encode(std::vector<unsigned char>& out,
 
 #ifdef LODEPNG_COMPILE_DISK
 /*
-Load a file from disk into an std::vector. If the vector is empty, then either
-the file doesn't exist or is an empty file.
+Load a file from disk into an std::vector.
+return value: error code (0 means ok)
 */
-void load_file(std::vector<unsigned char>& buffer, const std::string& filename);
+unsigned load_file(std::vector<unsigned char>& buffer, const std::string& filename);
 
 /*
 Save the binary data in an std::vector to a file on disk. The file is overwritten
@@ -1564,6 +1564,7 @@ yyyymmdd.
 Some changes aren't backwards compatible. Those are indicated with a (!)
 symbol.
 
+*) 08 dec 2015: Made load_file function return error if file can't be opened.
 *) 24 okt 2015: Bugfix with decoding to palette output.
 *) 18 apr 2015: Boundary PM instead of just package-merge for faster encoding.
 *) 23 aug 2014: Reduced needless memory usage of decoder.