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LibGfx/TIFF: Add support for LZW compression

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This commit is contained in:
Lucas CHOLLET 2023-11-04 17:22:54 -04:00 • committed by Andreas Kling
parent 4f5a0227e2
commit 272be6b20a
3 changed files with 56 additions and 1 deletions
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45
Userland/Libraries/LibGfx/ImageFormats/TIFFLoader.cpp
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@ -8,6 +8,7 @@
#include <AK/Debug.h>
#include <AK/Endian.h>
#include <AK/String.h>
#include <LibCompress/LZWDecoder.h>
namespace Gfx {
@ -108,10 +109,12 @@ private:
};
template<typename ByteReader>
ErrorOr<void> loop_over_pixels(ByteReader&& byte_reader)
ErrorOr<void> loop_over_pixels(ByteReader&& byte_reader, Function<ErrorOr<void>(u32)> initializer = {})
{
for (u32 strip_index = 0; strip_index < m_strip_offsets.size(); ++strip_index) {
TRY(m_stream->seek(m_strip_offsets[strip_index]));
if (initializer)
TRY(initializer(m_strip_bytes_count[strip_index]));
for (u32 row = 0; row < m_rows_per_strip; row++) {
auto const scanline = row + m_rows_per_strip * strip_index;
if (scanline >= static_cast<u32>(m_size.height()))
@ -145,6 +148,46 @@ private:
case Compression::NoCompression:
TRY(loop_over_pixels([this]() { return read_value<u8>(); }));
break;
case Compression::LZW: {
Vector<u8> result_buffer {};
Optional<Compress::LZWDecoder<BigEndianInputBitStream>> decoder {};
u16 clear_code {};
u16 end_of_information_code {};
auto initializer = [&](u32 bytes) -> ErrorOr<void> {
auto strip_stream = make<FixedMemoryStream>(TRY(m_stream->read_in_place<u8 const>(bytes)));
auto lzw_stream = make<BigEndianInputBitStream>(MaybeOwned<Stream>(move(strip_stream)));
decoder = Compress::LZWDecoder { MaybeOwned<BigEndianInputBitStream> { move(lzw_stream) }, 8, -1 };
clear_code = decoder->add_control_code();
end_of_information_code = decoder->add_control_code();
return {};
};
auto read_lzw_byte = [&]() -> ErrorOr<u8> {
while (true) {
if (!result_buffer.is_empty())
return result_buffer.take_first();
auto const code = TRY(decoder->next_code());
if (code == clear_code) {
decoder->reset();
continue;
}
if (code == end_of_information_code)
return Error::from_string_literal("TIFFImageDecoderPlugin: Reached end of LZW stream");
result_buffer = decoder->get_output();
}
};
TRY(loop_over_pixels([read_lzw_byte = move(read_lzw_byte)]() { return read_lzw_byte(); }, move(initializer)));
break;
}
case Compression::PackBits: {
// Section 9: PackBits Compression
Optional<i8> n;