Let's adapt this class a bit better to how it's actually being used.
Instead of having valid/invalid states and storing an error in case
it's invalid, a MappedFile is now always valid, and the factory
function that creates it will return an OSError if mapping fails.
Let's just say no to shenanigans by capping images at 16384 pixels both
wide and tall. If a day comes in the future where we need to handle
images larger than this, we can deal with it then.
Previously, in the case of RLE4, parsing took suspiciously long.
What happened was that 'pixel_count' was 255, and 'i' was incremented
by *two* in each iteration, so the for-loop continued until the
entire output buffer was full, and then rejected the RLE data
as bogus.
This little diff allows pixel_count to reach 256, be greater than
pixel_count, and thus terminate the loop in the intended way.
- OSv2 DIBs were not checked at all
- Regular Info DIBs had the compression checked after applying a 0xFF mask,
which let many invalid compression values pass.
- There may still be a separate latent bug that causes mask_sizes and mask_shifts to be empty.
This function did a const_cast internally which made the call side look
"safe". This method is removed completely and call sites are replaced
with ByteBuffer::wrap(const_cast<void*>(data), size) which makes the
behaviour obvious.
Adds an *almost fully featured BMP loader to process .bmp files.
Features:
- All header formats are supported
- Full RLE4/8/24 support
- Color scaling (e.g. distributing a 5-bit color throughout the 8-bit
color spectrum, so 5-bit white is still 0xffffff)
- Full BITMASK/ALPHABITMASK support
*Not included:
- 1D Huffman compression. Good luck actually finding a bmp in the wild
that uses this
- Use of any field in the V4/V5 header. Color spaces? Endpoints? No
thanks :)
This loader was tested with the images at
https://entropymine.com/jason/bmpsuite/bmpsuite/html/bmpsuite.html. This
loader correctly displays 81 out of the 90 total images (for reference,
firefox displays 64 correctly). Note that not rendering the images at
the bottom is counted as displaying correctly.
