And move canonicalized_path() to a static method on LexicalPath.
This is to make it clear that FileSystemPath/canonicalized_path() only
perform *lexical* canonicalization.
Various optimisations to speed up LZWDecoder
- Take advantage of the fact that we add new codes in the order they are
discovered so no need to store the code as part of a separate
CodeTableEntry structure. Instead we store directly store vectors of
colors and the code is the index into the vector.
- Cache current table capacity to avoid calling pow2 every time.
- Prevent some unnecessary vector copies by returning by reference from
get_output.
Adds methods to determine whether an image is animated, how many times
the animation loops, the number of frames, and to get individual frames.
Implements stubs of these methods for PNGImageDecoderPlugin and
GIFImageDecoderPlugin.
The LZW decode step will now copy and pad LZW data out to 4 bytes if there are
less than 4 bytes remaining in the buffer. This means it will now also work when
the total size of the LZW image data is less than 4 bytes.
The sniff method is intended to be used for content sniffing. It should be a
cheap test to rapidly rule out whether a candidate image can be successfully
decoded. For the GIF and PNG implementations it simply attempts to decode the
image header, returning true if successful and false if not.
Also:
- Define the GIFLoadingContext structure.
- The load_gif_impl function now returns load operation success, and takes a
reference to a GIFLoadingContext as input.
- Implement GIFImageDecoderPlugin::bitmap which calls onto load_gif_impl.
