diff options
| -rw-r--r-- | src/Fl_GIF_Image.cxx | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/src/Fl_GIF_Image.cxx b/src/Fl_GIF_Image.cxx index b006a4340..b6b51fb45 100644 --- a/src/Fl_GIF_Image.cxx +++ b/src/Fl_GIF_Image.cxx @@ -266,6 +266,8 @@ void Fl_GIF_Image::load_gif_(Fl_Image_Reader &rdr) int CodeSize; /* Code size, init from GIF header, increases... */ char Interlace; + // Main parser loop: parse "blocks" until an image is found or error + for (;;) { int i = rdr.read_byte(); @@ -303,8 +305,7 @@ void Fl_GIF_Image::load_gif_(Fl_Image_Reader &rdr) rdr.name(), ch, rdr.tell()-3, blocklen); ; // skip data } - } - else if (i == 0x2c) { // an image: Image Descriptor follows + } else if (i == 0x2c) { // an image: Image Descriptor follows // printf("Image Descriptor at offset %ld\n", rdr.tell()); rdr.read_word(); // Image Left Position rdr.read_word(); // Image Top Position @@ -325,18 +326,24 @@ void Fl_GIF_Image::load_gif_(Fl_Image_Reader &rdr) } CHECK_ERROR break; // okay, this is the image we want + } else if (i == 0x3b) { // Trailer (end of GIF data) + // printf("Trailer found at offset %ld\n", rdr.tell()); + Fl::error("%s: no image data found.", rdr.name()); + ld(ERR_NO_IMAGE); // this GIF file is "empty" (no image) + return; // terminate } else { - Fl::warning("%s: unknown GIF code 0x%02x at offset %ld", rdr.name(), i, rdr.tell()-1); - blocklen = 0; + Fl::error("%s: unknown GIF code 0x%02x at offset %ld", rdr.name(), i, rdr.tell()-1); + ld(ERR_FORMAT); // broken file + return; // terminate } CHECK_ERROR - // skip all the data subblocks: + // skip all data (sub)blocks: while (blocklen > 0) { rdr.skip(blocklen); blocklen = rdr.read_byte(); } - // printf("End of data at offset %ld\n", rdr.tell()); + // printf("End of data (sub)blocks at offset %ld\n", rdr.tell()); } // read image data @@ -407,6 +414,8 @@ void Fl_GIF_Image::load_gif_(Fl_Image_Reader &rdr) CHECK_ERROR int frombit = 0; + // loop to read LZW compressed image data + for (;;) { /* Fetch the next code from the raster data stream. The codes can be @@ -507,12 +516,13 @@ void Fl_GIF_Image::load_gif_(Fl_Image_Reader &rdr) OldCode = CurCode; } - // We are done reading the image, now convert to xpm: + // We are done reading the image, now convert to xpm - // allocate line pointer arrays: w(Width); h(Height); d(1); + + // allocate line pointer arrays: new_data = new char*[Height+2]; // transparent pixel must be zero, swap if it isn't: |