Fix decoding error with trailing comment extension blocks #12
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The GIF files that can be found on the Internet come in a wide variety of forms. Some strictly adhere to the original specification, others do not and differ in the actual sequence of blocks or their number. For this reason, my decoder has a kind of "virtual" FrameBlock, which can contain all possible blocks in different order that occur in a GIF animation. - Graphic Control Extension - Image Description - Local Color Table - Image Data Block - Plain Text Extension - Application Extension - Comment Extension The TableBasedImage block, which is a chain of ImageDescriptor, (Local Color Table) and ImageData, is used as a feature for terminating a FrameBlock. So far I have only seen GIF files that follow this scheme. However, there was one example where one (or more) comment extensions were added before the end. Here the decoding process failed. This fix also adds "global comments" that are not part of my FrameBlock and are appended to the GifDataStream afterwards.
olivervogel
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The GIF files that can be found on the Internet come in a wide variety of forms. Some strictly adhere to the original specification, others do not and differ in the actual sequence of blocks or their number.
For this reason, my decoder has a kind of "virtual" FrameBlock, which can contain all possible blocks in different order that occur in a GIF animation.
The TableBasedImage block, which is a chain of ImageDescriptor, (Local Color Table) and ImageData, is used as a feature for terminating a FrameBlock.
So far I have only seen GIF files that follow this scheme. However, there was one example where one (or more) comment extensions were added before the end. Here the decoding process failed.
This fix also adds "global comments" that are not part of my FrameBlock and are appended to the GifDataStream afterwards.