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https://github.com/RGBCube/serenity
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338d64abd9
Some images (like https://www.w3.org/Press/Stock/Berners-Lee/2001-europaeum-eighth.jpg) embed a non-compliant ICC profile. Instead of rejecting the image, we can simply discard the color profile and resume the decoding of the bitmap.
1979 lines
76 KiB
C++
1979 lines
76 KiB
C++
/*
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* Copyright (c) 2020, the SerenityOS developers.
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* Copyright (c) 2022-2023, Lucas Chollet <lucas.chollet@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Debug.h>
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#include <AK/Endian.h>
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#include <AK/Error.h>
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#include <AK/FixedArray.h>
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#include <AK/HashMap.h>
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#include <AK/Math.h>
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#include <AK/MemoryStream.h>
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#include <AK/NumericLimits.h>
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#include <AK/String.h>
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#include <AK/Try.h>
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#include <AK/Vector.h>
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#include <LibGfx/ImageFormats/JPEGLoader.h>
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#include <LibGfx/ImageFormats/JPEGShared.h>
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namespace Gfx {
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struct MacroblockMeta {
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u32 total { 0 };
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u32 padded_total { 0 };
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u32 hcount { 0 };
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u32 vcount { 0 };
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u32 hpadded_count { 0 };
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u32 vpadded_count { 0 };
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};
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// In the JPEG format, components are defined first at the frame level, then
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// referenced in each scan and aggregated with scan-specific information. The
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// two following structs mimic this hierarchy.
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struct Component {
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// B.2.2 - Frame header syntax
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u8 id { 0 }; // Ci, Component identifier
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u8 hsample_factor { 1 }; // Hi, Horizontal sampling factor
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u8 vsample_factor { 1 }; // Vi, Vertical sampling factor
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u8 quantization_table_id { 0 }; // Tqi, Quantization table destination selector
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// The JPEG specification does not specify which component corresponds to
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// Y, Cb or Cr. This field (actually the index in the parent Vector) will
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// act as an authority to determine the *real* component.
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// Please note that this is implementation specific.
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u8 index { 0 };
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};
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struct ScanComponent {
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// B.2.3 - Scan header syntax
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Component& component;
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u8 dc_destination_id { 0 }; // Tdj, DC entropy coding table destination selector
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u8 ac_destination_id { 0 }; // Taj, AC entropy coding table destination selector
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};
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struct StartOfFrame {
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// Of these, only the first 3 are in mainstream use, and refers to SOF0-2.
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enum class FrameType {
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Baseline_DCT = 0,
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Extended_Sequential_DCT = 1,
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Progressive_DCT = 2,
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Sequential_Lossless = 3,
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Differential_Sequential_DCT = 5,
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Differential_Progressive_DCT = 6,
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Differential_Sequential_Lossless = 7,
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Extended_Sequential_DCT_Arithmetic = 9,
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Progressive_DCT_Arithmetic = 10,
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Sequential_Lossless_Arithmetic = 11,
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Differential_Sequential_DCT_Arithmetic = 13,
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Differential_Progressive_DCT_Arithmetic = 14,
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Differential_Sequential_Lossless_Arithmetic = 15,
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};
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FrameType type { FrameType::Baseline_DCT };
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u8 precision { 0 };
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u16 height { 0 };
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u16 width { 0 };
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};
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struct HuffmanTable {
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u8 type { 0 };
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u8 destination_id { 0 };
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u8 code_counts[16] = { 0 };
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Vector<u8> symbols;
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Vector<u16> codes;
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// Note: The value 8 is chosen quite arbitrarily, the only current constraint
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// is that both the symbol and the size fit in an u16. I've tested more
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// values but none stand out, and 8 is the value used by libjpeg-turbo.
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static constexpr u8 bits_per_cached_code = 8;
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static constexpr u8 maximum_bits_per_code = 16;
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u8 first_non_cached_code_index {};
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void generate_codes()
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{
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unsigned code = 0;
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for (auto number_of_codes : code_counts) {
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for (int i = 0; i < number_of_codes; i++)
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codes.append(code++);
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code <<= 1;
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}
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generate_lookup_table();
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}
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struct SymbolAndSize {
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u8 symbol {};
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u8 size {};
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};
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ErrorOr<SymbolAndSize> symbol_from_code(u16 code) const
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{
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static constexpr u8 shift_for_cache = maximum_bits_per_code - bits_per_cached_code;
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if (lookup_table[code >> shift_for_cache] != invalid_entry) {
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u8 const code_length = lookup_table[code >> shift_for_cache] >> bits_per_cached_code;
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return SymbolAndSize { static_cast<u8>(lookup_table[code >> shift_for_cache]), code_length };
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}
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u64 code_cursor = first_non_cached_code_index;
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for (u8 i = HuffmanTable::bits_per_cached_code; i < 16; i++) {
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auto const result = code >> (maximum_bits_per_code - 1 - i);
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for (u32 j = 0; j < code_counts[i]; j++) {
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if (result == codes[code_cursor])
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return SymbolAndSize { symbols[code_cursor], static_cast<u8>(i + 1) };
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code_cursor++;
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}
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}
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return Error::from_string_literal("This kind of JPEG is not yet supported by the decoder");
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}
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private:
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static constexpr u16 invalid_entry = 0xFF;
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void generate_lookup_table()
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{
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lookup_table.fill(invalid_entry);
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u32 code_offset = 0;
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for (u8 code_length = 1; code_length <= bits_per_cached_code; code_length++) {
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for (u32 i = 0; i < code_counts[code_length - 1]; i++, code_offset++) {
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u32 code_key = codes[code_offset] << (bits_per_cached_code - code_length);
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for (u8 duplicate_count = 1 << (bits_per_cached_code - code_length); duplicate_count > 0; duplicate_count--) {
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lookup_table[code_key] = (code_length << bits_per_cached_code) | symbols[code_offset];
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code_key++;
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}
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}
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}
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}
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Array<u16, 1 << bits_per_cached_code> lookup_table {};
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};
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class HuffmanStream;
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class JPEGStream {
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public:
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static ErrorOr<JPEGStream> create(NonnullOwnPtr<Stream> stream)
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{
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Vector<u8> buffer;
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TRY(buffer.try_resize(buffer_size));
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JPEGStream jpeg_stream { move(stream), move(buffer) };
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TRY(jpeg_stream.refill_buffer());
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return jpeg_stream;
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}
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ALWAYS_INLINE ErrorOr<u8> read_u8()
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{
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if (m_byte_offset == m_current_size)
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TRY(refill_buffer());
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return m_buffer[m_byte_offset++];
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}
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ALWAYS_INLINE ErrorOr<u16> read_u16()
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{
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if (m_saved_marker.has_value())
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return m_saved_marker.release_value();
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return (static_cast<u16>(TRY(read_u8())) << 8) | TRY(read_u8());
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}
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ALWAYS_INLINE ErrorOr<void> discard(u64 bytes)
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{
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auto const discarded_from_buffer = min(m_current_size - m_byte_offset, bytes);
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m_byte_offset += discarded_from_buffer;
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if (discarded_from_buffer < bytes)
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TRY(m_stream->discard(bytes - discarded_from_buffer));
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return {};
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}
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ErrorOr<void> read_until_filled(Bytes bytes)
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{
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auto const copied = m_buffer.span().slice(m_byte_offset).copy_trimmed_to(bytes);
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m_byte_offset += copied;
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if (copied < bytes.size())
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TRY(m_stream->read_until_filled(bytes.slice(copied)));
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return {};
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}
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Optional<u16>& saved_marker(Badge<HuffmanStream>)
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{
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return m_saved_marker;
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}
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u64 byte_offset() const
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{
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return m_byte_offset;
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}
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private:
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JPEGStream(NonnullOwnPtr<Stream> stream, Vector<u8> buffer)
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: m_stream(move(stream))
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, m_buffer(move(buffer))
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{
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}
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ErrorOr<void> refill_buffer()
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{
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VERIFY(m_byte_offset == m_current_size);
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m_current_size = TRY(m_stream->read_some(m_buffer.span())).size();
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m_byte_offset = 0;
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return {};
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}
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static constexpr auto buffer_size = 4096;
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NonnullOwnPtr<Stream> m_stream;
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Optional<u16> m_saved_marker {};
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Vector<u8> m_buffer {};
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u64 m_byte_offset { buffer_size };
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u64 m_current_size { buffer_size };
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};
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class HuffmanStream {
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public:
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ALWAYS_INLINE ErrorOr<u8> next_symbol(HuffmanTable const& table)
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{
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u16 const code = TRY(peek_bits(HuffmanTable::maximum_bits_per_code));
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auto const symbol_and_size = TRY(table.symbol_from_code(code));
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TRY(discard_bits(symbol_and_size.size));
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return symbol_and_size.symbol;
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}
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ALWAYS_INLINE ErrorOr<u16> read_bits(u8 count = 1)
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{
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if (count > NumericLimits<u16>::digits()) {
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dbgln_if(JPEG_DEBUG, "Can't read {} bits at once!", count);
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return Error::from_string_literal("Reading too much huffman bits at once");
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}
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u16 const value = TRY(peek_bits(count));
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TRY(discard_bits(count));
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return value;
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}
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ALWAYS_INLINE ErrorOr<u16> peek_bits(u8 count)
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{
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if (count == 0)
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return 0;
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if (count + m_bit_offset > bits_in_reservoir)
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TRY(refill_reservoir());
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auto const mask = NumericLimits<u16>::max() >> (NumericLimits<u16>::digits() - count);
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return static_cast<u16>((m_bit_reservoir >> (bits_in_reservoir - m_bit_offset - count)) & mask);
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}
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ALWAYS_INLINE ErrorOr<void> discard_bits(u8 count)
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{
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m_bit_offset += count;
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if (m_bit_offset > bits_in_reservoir) {
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// FIXME: I can't find a test case for that so let's leave it for later
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// instead of inserting an hard-to-find bug.
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TODO();
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}
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return {};
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}
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ErrorOr<void> advance_to_byte_boundary()
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{
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if (auto remainder = m_bit_offset % 8; remainder != 0)
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TRY(discard_bits(bits_per_byte - remainder));
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return {};
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}
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HuffmanStream(JPEGStream& stream)
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: jpeg_stream(stream)
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{
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}
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private:
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ALWAYS_INLINE ErrorOr<void> refill_reservoir()
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{
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auto const bytes_needed = m_bit_offset / bits_per_byte;
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u8 bytes_added {};
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auto const append_byte = [&](u8 byte) {
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m_last_byte_was_ff = false;
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m_bit_reservoir <<= 8;
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m_bit_reservoir |= byte;
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m_bit_offset -= 8;
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bytes_added++;
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};
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do {
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// Note: We fake zeroes when we have reached another segment
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// It allows us to continue peeking seamlessly.
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u8 const next_byte = jpeg_stream.saved_marker({}).has_value() ? 0 : TRY(jpeg_stream.read_u8());
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if (m_last_byte_was_ff) {
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if (next_byte == 0xFF)
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continue;
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if (next_byte == 0x00) {
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append_byte(0xFF);
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continue;
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}
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Marker const marker = 0xFF00 | next_byte;
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if (marker < JPEG_RST0 || marker > JPEG_RST7) {
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// Note: The only way to know that we reached the end of a segment is to read
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// the marker of the following one. So we store it for later use.
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jpeg_stream.saved_marker({}) = marker;
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m_last_byte_was_ff = false;
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continue;
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}
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}
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if (next_byte == 0xFF) {
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m_last_byte_was_ff = true;
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continue;
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}
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append_byte(next_byte);
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} while (bytes_added < bytes_needed);
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return {};
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}
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JPEGStream& jpeg_stream;
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using Reservoir = u64;
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static constexpr auto bits_per_byte = 8;
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static constexpr auto bits_in_reservoir = sizeof(Reservoir) * bits_per_byte;
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Reservoir m_bit_reservoir {};
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u8 m_bit_offset { bits_in_reservoir };
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bool m_last_byte_was_ff { false };
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};
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struct ICCMultiChunkState {
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u8 seen_number_of_icc_chunks { 0 };
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FixedArray<ByteBuffer> chunks;
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};
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struct Scan {
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Scan(HuffmanStream stream)
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: huffman_stream(stream)
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{
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}
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// B.2.3 - Scan header syntax
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Vector<ScanComponent, 4> components;
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u8 spectral_selection_start {}; // Ss
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u8 spectral_selection_end {}; // Se
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u8 successive_approximation_high {}; // Ah
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u8 successive_approximation_low {}; // Al
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HuffmanStream huffman_stream;
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u64 end_of_bands_run_count { 0 };
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// See the note on Figure B.4 - Scan header syntax
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bool are_components_interleaved() const
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{
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return components.size() != 1;
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}
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};
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enum class ColorTransform {
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// https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-T.872-201206-I!!PDF-E&type=items
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// 6.5.3 - APP14 marker segment for colour encoding
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CmykOrRgb = 0,
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YCbCr = 1,
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YCCK = 2,
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};
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struct JPEGLoadingContext {
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JPEGLoadingContext(JPEGStream jpeg_stream)
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: stream(move(jpeg_stream))
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{
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}
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static ErrorOr<NonnullOwnPtr<JPEGLoadingContext>> create(NonnullOwnPtr<Stream> stream)
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{
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auto jpeg_stream = TRY(JPEGStream::create(move(stream)));
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return make<JPEGLoadingContext>(move(jpeg_stream));
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}
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enum State {
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NotDecoded = 0,
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Error,
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FrameDecoded,
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HeaderDecoded,
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BitmapDecoded
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};
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State state { State::NotDecoded };
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Array<Optional<Array<u16, 64>>, 4> quantization_tables {};
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StartOfFrame frame;
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u8 hsample_factor { 0 };
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u8 vsample_factor { 0 };
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Optional<Scan> current_scan {};
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Vector<Component, 4> components;
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RefPtr<Gfx::Bitmap> bitmap;
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u16 dc_restart_interval { 0 };
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HashMap<u8, HuffmanTable> dc_tables;
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HashMap<u8, HuffmanTable> ac_tables;
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Array<i16, 4> previous_dc_values {};
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MacroblockMeta mblock_meta;
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JPEGStream stream;
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Optional<ColorTransform> color_transform {};
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Optional<ICCMultiChunkState> icc_multi_chunk_state;
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Optional<ByteBuffer> icc_data;
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};
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static inline auto* get_component(Macroblock& block, unsigned component)
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{
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switch (component) {
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case 0:
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return block.y;
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case 1:
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return block.cb;
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case 2:
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return block.cr;
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case 3:
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return block.k;
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default:
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VERIFY_NOT_REACHED();
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}
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}
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static ErrorOr<void> refine_coefficient(Scan& scan, auto& coefficient)
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{
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// G.1.2.3 - Coding model for subsequent scans of successive approximation
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// See the correction bit from rule b.
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u8 const bit = TRY(scan.huffman_stream.read_bits(1));
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if (bit == 1)
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coefficient |= 1 << scan.successive_approximation_low;
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return {};
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}
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enum class JPEGDecodingMode {
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Sequential,
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Progressive
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};
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template<JPEGDecodingMode DecodingMode>
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static ErrorOr<void> add_dc(JPEGLoadingContext& context, Macroblock& macroblock, ScanComponent const& scan_component)
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{
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auto maybe_table = context.dc_tables.get(scan_component.dc_destination_id);
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if (!maybe_table.has_value()) {
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dbgln_if(JPEG_DEBUG, "Unable to find a DC table with id: {}", scan_component.dc_destination_id);
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return Error::from_string_literal("Unable to find corresponding DC table");
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}
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auto& dc_table = maybe_table.value();
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auto& scan = *context.current_scan;
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auto* select_component = get_component(macroblock, scan_component.component.index);
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auto& coefficient = select_component[0];
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if (DecodingMode == JPEGDecodingMode::Progressive && scan.successive_approximation_high > 0) {
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TRY(refine_coefficient(scan, coefficient));
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return {};
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}
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// For DC coefficients, symbol encodes the length of the coefficient.
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auto dc_length = TRY(scan.huffman_stream.next_symbol(dc_table));
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// F.1.2.1.2 - Defining Huffman tables for the DC coefficients
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// F.1.5.1 - Structure of DC code table for 12-bit sample precision
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if ((context.frame.precision == 8 && dc_length > 11)
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|| (context.frame.precision == 12 && dc_length > 15)) {
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dbgln_if(JPEG_DEBUG, "DC coefficient too long: {}!", dc_length);
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return Error::from_string_literal("DC coefficient too long");
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}
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// DC coefficients are encoded as the difference between previous and current DC values.
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i16 dc_diff = TRY(scan.huffman_stream.read_bits(dc_length));
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// If MSB in diff is 0, the difference is -ve. Otherwise +ve.
|
||
if (dc_length != 0 && dc_diff < (1 << (dc_length - 1)))
|
||
dc_diff -= (1 << dc_length) - 1;
|
||
|
||
auto& previous_dc = context.previous_dc_values[scan_component.component.index];
|
||
previous_dc += dc_diff;
|
||
coefficient = previous_dc << scan.successive_approximation_low;
|
||
|
||
return {};
|
||
}
|
||
|
||
template<JPEGDecodingMode DecodingMode>
|
||
static ALWAYS_INLINE ErrorOr<bool> read_eob(Scan& scan, u32 symbol)
|
||
{
|
||
// OPTIMIZATION: This is a fast path for sequential JPEGs, these
|
||
// only supports EOB with a value of one block.
|
||
if constexpr (DecodingMode == JPEGDecodingMode::Sequential)
|
||
return symbol == 0x00;
|
||
|
||
// G.1.2.2 - Progressive encoding of AC coefficients with Huffman coding
|
||
// Note: We also use it for non-progressive encoding as it supports both EOB and ZRL
|
||
|
||
if (auto const eob = symbol & 0x0F; eob == 0 && symbol != JPEG_ZRL) {
|
||
// We encountered an EOB marker
|
||
auto const eob_base = symbol >> 4;
|
||
auto const additional_value = TRY(scan.huffman_stream.read_bits(eob_base));
|
||
|
||
scan.end_of_bands_run_count = additional_value + (1 << eob_base) - 1;
|
||
|
||
// end_of_bands_run_count is decremented at the end of `build_macroblocks`.
|
||
// And we need to now that we reached End of Block in `add_ac`.
|
||
++scan.end_of_bands_run_count;
|
||
|
||
return true;
|
||
}
|
||
|
||
return false;
|
||
}
|
||
|
||
static bool is_progressive(StartOfFrame::FrameType frame_type)
|
||
{
|
||
return frame_type == StartOfFrame::FrameType::Progressive_DCT
|
||
|| frame_type == StartOfFrame::FrameType::Progressive_DCT_Arithmetic
|
||
|| frame_type == StartOfFrame::FrameType::Differential_Progressive_DCT
|
||
|| frame_type == StartOfFrame::FrameType::Differential_Progressive_DCT_Arithmetic;
|
||
}
|
||
|
||
template<JPEGDecodingMode DecodingMode>
|
||
static ErrorOr<void> add_ac(JPEGLoadingContext& context, Macroblock& macroblock, ScanComponent const& scan_component)
|
||
{
|
||
auto maybe_table = context.ac_tables.get(scan_component.ac_destination_id);
|
||
if (!maybe_table.has_value()) {
|
||
dbgln_if(JPEG_DEBUG, "Unable to find a AC table with id: {}", scan_component.ac_destination_id);
|
||
return Error::from_string_literal("Unable to find corresponding AC table");
|
||
}
|
||
|
||
auto& ac_table = maybe_table.value();
|
||
auto* select_component = get_component(macroblock, scan_component.component.index);
|
||
|
||
auto& scan = *context.current_scan;
|
||
|
||
// Compute the AC coefficients.
|
||
|
||
// 0th coefficient is the dc, which is already handled
|
||
auto first_coefficient = max(1, scan.spectral_selection_start);
|
||
|
||
u32 to_skip = 0;
|
||
Optional<u8> saved_symbol;
|
||
Optional<u8> saved_bit_for_rule_a;
|
||
bool in_zrl = false;
|
||
|
||
for (int j = first_coefficient; j <= scan.spectral_selection_end; ++j) {
|
||
auto& coefficient = select_component[zigzag_map[j]];
|
||
|
||
// AC symbols encode 2 pieces of information, the high 4 bits represent
|
||
// number of zeroes to be stuffed before reading the coefficient. Low 4
|
||
// bits represent the magnitude of the coefficient.
|
||
if (!in_zrl && scan.end_of_bands_run_count == 0 && !saved_symbol.has_value()) {
|
||
saved_symbol = TRY(scan.huffman_stream.next_symbol(ac_table));
|
||
|
||
if (!TRY(read_eob<DecodingMode>(scan, *saved_symbol))) {
|
||
to_skip = *saved_symbol >> 4;
|
||
|
||
in_zrl = *saved_symbol == JPEG_ZRL;
|
||
if (in_zrl) {
|
||
to_skip++;
|
||
saved_symbol.clear();
|
||
}
|
||
|
||
if constexpr (DecodingMode == JPEGDecodingMode::Sequential) {
|
||
j += to_skip - 1;
|
||
to_skip = 0;
|
||
in_zrl = false;
|
||
continue;
|
||
}
|
||
|
||
if constexpr (DecodingMode == JPEGDecodingMode::Progressive) {
|
||
if (!in_zrl && scan.successive_approximation_high != 0) {
|
||
// G.1.2.3 - Coding model for subsequent scans of successive approximation
|
||
// Bit sign from rule a
|
||
saved_bit_for_rule_a = TRY(scan.huffman_stream.read_bits(1));
|
||
}
|
||
}
|
||
} else if constexpr (DecodingMode == JPEGDecodingMode::Sequential) {
|
||
break;
|
||
}
|
||
}
|
||
|
||
if constexpr (DecodingMode == JPEGDecodingMode::Progressive) {
|
||
if (coefficient != 0) {
|
||
TRY(refine_coefficient(scan, coefficient));
|
||
continue;
|
||
}
|
||
}
|
||
|
||
if (to_skip > 0) {
|
||
--to_skip;
|
||
if (to_skip == 0)
|
||
in_zrl = false;
|
||
continue;
|
||
}
|
||
|
||
if (scan.end_of_bands_run_count > 0)
|
||
continue;
|
||
|
||
if (DecodingMode == JPEGDecodingMode::Progressive && scan.successive_approximation_high != 0) {
|
||
// G.1.2.3 - Coding model for subsequent scans of successive approximation
|
||
if (auto const low_bits = *saved_symbol & 0x0F; low_bits != 1) {
|
||
dbgln_if(JPEG_DEBUG, "AC coefficient low bits isn't equal to 1: {}!", low_bits);
|
||
return Error::from_string_literal("AC coefficient low bits isn't equal to 1");
|
||
}
|
||
|
||
coefficient = (*saved_bit_for_rule_a == 0 ? -1 : 1) << scan.successive_approximation_low;
|
||
saved_bit_for_rule_a.clear();
|
||
} else {
|
||
// F.1.2.2 - Huffman encoding of AC coefficients
|
||
u8 const coeff_length = *saved_symbol & 0x0F;
|
||
|
||
// F.1.2.2.1 - Structure of AC code table
|
||
// F.1.5.2 - Structure of AC code table for 12-bit sample precision
|
||
if ((context.frame.precision == 8 && coeff_length > 10)
|
||
|| (context.frame.precision == 12 && coeff_length > 14)) {
|
||
dbgln_if(JPEG_DEBUG, "AC coefficient too long: {}!", coeff_length);
|
||
return Error::from_string_literal("AC coefficient too long");
|
||
}
|
||
|
||
if (coeff_length != 0) {
|
||
i32 ac_coefficient = TRY(scan.huffman_stream.read_bits(coeff_length));
|
||
if (ac_coefficient < (1 << (coeff_length - 1)))
|
||
ac_coefficient -= (1 << coeff_length) - 1;
|
||
|
||
coefficient = ac_coefficient * (1 << scan.successive_approximation_low);
|
||
}
|
||
}
|
||
|
||
saved_symbol.clear();
|
||
}
|
||
|
||
if (to_skip > 0) {
|
||
dbgln_if(JPEG_DEBUG, "Run-length exceeded boundaries. Cursor: {}, Skipping: {}!", scan.spectral_selection_end + to_skip, to_skip);
|
||
return Error::from_string_literal("Run-length exceeded boundaries");
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
/**
|
||
* Build the macroblocks possible by reading single (MCU) subsampled pair of CbCr.
|
||
* Depending on the sampling factors, we may not see triples of y, cb, cr in that
|
||
* order. If sample factors differ from one, we'll read more than one block of y-
|
||
* coefficients before we get to read a cb-cr block.
|
||
|
||
* In the function below, `hcursor` and `vcursor` denote the location of the block
|
||
* we're building in the macroblock matrix. `vfactor_i` and `hfactor_i` are cursors
|
||
* that iterate over the vertical and horizontal subsampling factors, respectively.
|
||
* When we finish one iteration of the innermost loop, we'll have the coefficients
|
||
* of one of the components of block at position `macroblock_index`. When the outermost
|
||
* loop finishes first iteration, we'll have all the luminance coefficients for all the
|
||
* macroblocks that share the chrominance data. Next two iterations (assuming that
|
||
* we are dealing with three components) will fill up the blocks with chroma data.
|
||
*/
|
||
template<JPEGDecodingMode DecodingMode>
|
||
static ErrorOr<void> build_macroblocks(JPEGLoadingContext& context, Vector<Macroblock>& macroblocks, u32 hcursor, u32 vcursor)
|
||
{
|
||
for (auto const& scan_component : context.current_scan->components) {
|
||
for (u8 vfactor_i = 0; vfactor_i < scan_component.component.vsample_factor; vfactor_i++) {
|
||
for (u8 hfactor_i = 0; hfactor_i < scan_component.component.hsample_factor; hfactor_i++) {
|
||
// A.2.3 - Interleaved order
|
||
u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor);
|
||
if (!context.current_scan->are_components_interleaved()) {
|
||
macroblock_index = vcursor * context.mblock_meta.hpadded_count + (hfactor_i + (hcursor * scan_component.component.vsample_factor) + (vfactor_i * scan_component.component.hsample_factor));
|
||
|
||
// A.2.4 Completion of partial MCU
|
||
// If the component is [and only if!] to be interleaved, the encoding process
|
||
// shall also extend the number of samples by one or more additional blocks.
|
||
|
||
// Horizontally
|
||
if (macroblock_index >= context.mblock_meta.hcount && macroblock_index % context.mblock_meta.hpadded_count >= context.mblock_meta.hcount)
|
||
continue;
|
||
// Vertically
|
||
if (macroblock_index >= context.mblock_meta.hpadded_count * context.mblock_meta.vcount)
|
||
continue;
|
||
}
|
||
|
||
Macroblock& block = macroblocks[macroblock_index];
|
||
|
||
if constexpr (DecodingMode == JPEGDecodingMode::Sequential) {
|
||
TRY(add_dc<DecodingMode>(context, block, scan_component));
|
||
TRY(add_ac<DecodingMode>(context, block, scan_component));
|
||
} else {
|
||
if (context.current_scan->spectral_selection_start == 0)
|
||
TRY(add_dc<DecodingMode>(context, block, scan_component));
|
||
if (context.current_scan->spectral_selection_end != 0)
|
||
TRY(add_ac<DecodingMode>(context, block, scan_component));
|
||
|
||
// G.1.2.2 - Progressive encoding of AC coefficients with Huffman coding
|
||
if (context.current_scan->end_of_bands_run_count > 0) {
|
||
--context.current_scan->end_of_bands_run_count;
|
||
continue;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
static bool is_dct_based(StartOfFrame::FrameType frame_type)
|
||
{
|
||
return frame_type == StartOfFrame::FrameType::Baseline_DCT
|
||
|| frame_type == StartOfFrame::FrameType::Extended_Sequential_DCT
|
||
|| frame_type == StartOfFrame::FrameType::Progressive_DCT
|
||
|| frame_type == StartOfFrame::FrameType::Differential_Sequential_DCT
|
||
|| frame_type == StartOfFrame::FrameType::Differential_Progressive_DCT
|
||
|| frame_type == StartOfFrame::FrameType::Progressive_DCT_Arithmetic
|
||
|| frame_type == StartOfFrame::FrameType::Differential_Sequential_DCT_Arithmetic
|
||
|| frame_type == StartOfFrame::FrameType::Differential_Progressive_DCT_Arithmetic;
|
||
}
|
||
|
||
static void reset_decoder(JPEGLoadingContext& context)
|
||
{
|
||
// G.1.2.2 - Progressive encoding of AC coefficients with Huffman coding
|
||
context.current_scan->end_of_bands_run_count = 0;
|
||
|
||
// E.2.4 Control procedure for decoding a restart interval
|
||
if (is_dct_based(context.frame.type)) {
|
||
context.previous_dc_values = {};
|
||
return;
|
||
}
|
||
|
||
VERIFY_NOT_REACHED();
|
||
}
|
||
|
||
static ErrorOr<void> decode_huffman_stream(JPEGLoadingContext& context, Vector<Macroblock>& macroblocks)
|
||
{
|
||
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
|
||
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
|
||
u32 i = vcursor * context.mblock_meta.hpadded_count + hcursor;
|
||
|
||
auto& huffman_stream = context.current_scan->huffman_stream;
|
||
|
||
if (context.dc_restart_interval > 0) {
|
||
if (i != 0 && i % (context.dc_restart_interval * context.vsample_factor * context.hsample_factor) == 0) {
|
||
reset_decoder(context);
|
||
|
||
// Restart markers are stored in byte boundaries. Advance the huffman stream cursor to
|
||
// the 0th bit of the next byte.
|
||
TRY(huffman_stream.advance_to_byte_boundary());
|
||
|
||
// Skip the restart marker (RSTn).
|
||
TRY(huffman_stream.discard_bits(8));
|
||
}
|
||
}
|
||
|
||
auto result = [&]() {
|
||
if (is_progressive(context.frame.type))
|
||
return build_macroblocks<JPEGDecodingMode::Progressive>(context, macroblocks, hcursor, vcursor);
|
||
return build_macroblocks<JPEGDecodingMode::Sequential>(context, macroblocks, hcursor, vcursor);
|
||
}();
|
||
|
||
if (result.is_error()) {
|
||
if constexpr (JPEG_DEBUG) {
|
||
dbgln("Failed to build Macroblock {}: {}", i, result.error());
|
||
dbgln("Huffman stream byte offset {}", context.stream.byte_offset());
|
||
}
|
||
return result.release_error();
|
||
}
|
||
}
|
||
}
|
||
return {};
|
||
}
|
||
|
||
static bool is_frame_marker(Marker const marker)
|
||
{
|
||
// B.1.1.3 - Marker assignments
|
||
bool const is_sof_marker = marker >= JPEG_SOF0 && marker <= JPEG_SOF15;
|
||
|
||
// Start of frame markers are valid for JPEG_SOF0 to JPEG_SOF15 except number 4, 8 (reserved) and 12.
|
||
bool const is_defined_marker = marker != JPEG_DHT && marker != 0xFFC8 && marker != JPEG_DAC;
|
||
|
||
return is_sof_marker && is_defined_marker;
|
||
}
|
||
|
||
static inline bool is_supported_marker(Marker const marker)
|
||
{
|
||
if (marker >= JPEG_APPN0 && marker <= JPEG_APPN15) {
|
||
|
||
if (marker != JPEG_APPN0 && marker != JPEG_APPN14)
|
||
dbgln_if(JPEG_DEBUG, "{:#04x} not supported yet. The decoder may fail!", marker);
|
||
return true;
|
||
}
|
||
if (marker >= JPEG_RESERVED1 && marker <= JPEG_RESERVEDD)
|
||
return true;
|
||
if (marker >= JPEG_RST0 && marker <= JPEG_RST7)
|
||
return true;
|
||
switch (marker) {
|
||
case JPEG_COM:
|
||
case JPEG_DHP:
|
||
case JPEG_EXP:
|
||
case JPEG_DHT:
|
||
case JPEG_DQT:
|
||
case JPEG_DRI:
|
||
case JPEG_EOI:
|
||
case JPEG_SOF0:
|
||
case JPEG_SOF1:
|
||
case JPEG_SOF2:
|
||
case JPEG_SOI:
|
||
case JPEG_SOS:
|
||
return true;
|
||
}
|
||
|
||
if (is_frame_marker(marker))
|
||
dbgln_if(JPEG_DEBUG, "Decoding this frame-type (SOF{}) is not currently supported. Decoder will fail!", marker & 0xf);
|
||
|
||
return false;
|
||
}
|
||
|
||
static inline ErrorOr<Marker> read_marker_at_cursor(JPEGStream& stream)
|
||
{
|
||
u16 marker = TRY(stream.read_u16());
|
||
|
||
if (marker == 0xFFFF) {
|
||
u8 next { 0xFF };
|
||
|
||
while (next == 0xFF)
|
||
next = TRY(stream.read_u8());
|
||
|
||
marker = 0xFF00 | next;
|
||
}
|
||
|
||
if (is_supported_marker(marker))
|
||
return marker;
|
||
|
||
return Error::from_string_literal("Reached an unsupported marker");
|
||
}
|
||
|
||
static ErrorOr<u16> read_effective_chunk_size(JPEGStream& stream)
|
||
{
|
||
// The stored chunk size includes the size of `stored_size` itself.
|
||
u16 const stored_size = TRY(stream.read_u16());
|
||
if (stored_size < 2)
|
||
return Error::from_string_literal("Stored chunk size is too small");
|
||
return stored_size - 2;
|
||
}
|
||
|
||
static ErrorOr<void> read_start_of_scan(JPEGStream& stream, JPEGLoadingContext& context)
|
||
{
|
||
// B.2.3 - Scan header syntax
|
||
|
||
if (context.state < JPEGLoadingContext::State::FrameDecoded)
|
||
return Error::from_string_literal("SOS found before reading a SOF");
|
||
|
||
[[maybe_unused]] u16 const bytes_to_read = TRY(read_effective_chunk_size(stream));
|
||
u8 const component_count = TRY(stream.read_u8());
|
||
|
||
Scan current_scan(HuffmanStream { context.stream });
|
||
|
||
Optional<u8> last_read;
|
||
u8 component_read = 0;
|
||
for (auto& component : context.components) {
|
||
// See the Csj paragraph:
|
||
// [...] the ordering in the scan header shall follow the ordering in the frame header.
|
||
if (component_read == component_count)
|
||
break;
|
||
|
||
if (!last_read.has_value())
|
||
last_read = TRY(stream.read_u8());
|
||
|
||
if (component.id != *last_read)
|
||
continue;
|
||
|
||
u8 const table_ids = TRY(stream.read_u8());
|
||
|
||
current_scan.components.empend(component, static_cast<u8>(table_ids >> 4), static_cast<u8>(table_ids & 0x0F));
|
||
|
||
component_read++;
|
||
last_read.clear();
|
||
}
|
||
|
||
if constexpr (JPEG_DEBUG) {
|
||
StringBuilder builder;
|
||
TRY(builder.try_append("Components in scan: "sv));
|
||
for (auto const& scan_component : current_scan.components) {
|
||
TRY(builder.try_append(TRY(String::number(scan_component.component.id))));
|
||
TRY(builder.try_append(' '));
|
||
}
|
||
dbgln(builder.string_view());
|
||
}
|
||
|
||
current_scan.spectral_selection_start = TRY(stream.read_u8());
|
||
current_scan.spectral_selection_end = TRY(stream.read_u8());
|
||
auto const successive_approximation = TRY(stream.read_u8());
|
||
current_scan.successive_approximation_high = successive_approximation >> 4;
|
||
current_scan.successive_approximation_low = successive_approximation & 0x0F;
|
||
|
||
dbgln_if(JPEG_DEBUG, "Start of Selection: {}, End of Selection: {}, Successive Approximation High: {}, Successive Approximation Low: {}",
|
||
current_scan.spectral_selection_start,
|
||
current_scan.spectral_selection_end,
|
||
current_scan.successive_approximation_high,
|
||
current_scan.successive_approximation_low);
|
||
|
||
if (current_scan.spectral_selection_start > 63 || current_scan.spectral_selection_end > 63 || current_scan.successive_approximation_high > 13 || current_scan.successive_approximation_low > 13) {
|
||
dbgln_if(JPEG_DEBUG, "ERROR! Start of Selection: {}, End of Selection: {}, Successive Approximation High: {}, Successive Approximation Low: {}!",
|
||
current_scan.spectral_selection_start,
|
||
current_scan.spectral_selection_end,
|
||
current_scan.successive_approximation_high,
|
||
current_scan.successive_approximation_low);
|
||
return Error::from_string_literal("Spectral selection is not [0,63] or successive approximation is not null");
|
||
}
|
||
|
||
context.current_scan = move(current_scan);
|
||
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> read_restart_interval(JPEGStream& stream, JPEGLoadingContext& context)
|
||
{
|
||
// B.2.4.4 - Restart interval definition syntax
|
||
u16 bytes_to_read = TRY(read_effective_chunk_size(stream));
|
||
if (bytes_to_read != 2) {
|
||
dbgln_if(JPEG_DEBUG, "Malformed DRI marker found!");
|
||
return Error::from_string_literal("Malformed DRI marker found");
|
||
}
|
||
context.dc_restart_interval = TRY(stream.read_u16());
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> read_huffman_table(JPEGStream& stream, JPEGLoadingContext& context)
|
||
{
|
||
// B.2.4.2 - Huffman table-specification syntax
|
||
|
||
u16 bytes_to_read = TRY(read_effective_chunk_size(stream));
|
||
|
||
while (bytes_to_read > 0) {
|
||
HuffmanTable table;
|
||
u8 const table_info = TRY(stream.read_u8());
|
||
u8 const table_type = table_info >> 4;
|
||
u8 const table_destination_id = table_info & 0x0F;
|
||
if (table_type > 1) {
|
||
dbgln_if(JPEG_DEBUG, "Unrecognized huffman table: {}!", table_type);
|
||
return Error::from_string_literal("Unrecognized huffman table");
|
||
}
|
||
|
||
if ((context.frame.type == StartOfFrame::FrameType::Baseline_DCT && table_destination_id > 1)
|
||
|| (context.frame.type != StartOfFrame::FrameType::Baseline_DCT && table_destination_id > 3)) {
|
||
dbgln_if(JPEG_DEBUG, "Invalid huffman table destination id: {}!", table_destination_id);
|
||
return Error::from_string_literal("Invalid huffman table destination id");
|
||
}
|
||
|
||
table.type = table_type;
|
||
table.destination_id = table_destination_id;
|
||
u32 total_codes = 0;
|
||
|
||
// Read code counts. At each index K, the value represents the number of K+1 bit codes in this header.
|
||
for (int i = 0; i < 16; i++) {
|
||
if (i == HuffmanTable::bits_per_cached_code)
|
||
table.first_non_cached_code_index = total_codes;
|
||
u8 const count = TRY(stream.read_u8());
|
||
total_codes += count;
|
||
table.code_counts[i] = count;
|
||
}
|
||
|
||
table.codes.ensure_capacity(total_codes);
|
||
table.symbols.ensure_capacity(total_codes);
|
||
|
||
// Read symbols. Read X bytes, where X is the sum of the counts of codes read in the previous step.
|
||
for (u32 i = 0; i < total_codes; i++) {
|
||
u8 symbol = TRY(stream.read_u8());
|
||
table.symbols.append(symbol);
|
||
}
|
||
|
||
table.generate_codes();
|
||
|
||
auto& huffman_table = table.type == 0 ? context.dc_tables : context.ac_tables;
|
||
huffman_table.set(table.destination_id, table);
|
||
|
||
bytes_to_read -= 1 + 16 + total_codes;
|
||
}
|
||
|
||
if (bytes_to_read != 0) {
|
||
dbgln_if(JPEG_DEBUG, "Extra bytes detected in huffman header!");
|
||
return Error::from_string_literal("Extra bytes detected in huffman header");
|
||
}
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> read_icc_profile(JPEGStream& stream, JPEGLoadingContext& context, int bytes_to_read)
|
||
{
|
||
// https://www.color.org/technotes/ICC-Technote-ProfileEmbedding.pdf, page 5, "JFIF".
|
||
if (bytes_to_read <= 2) {
|
||
dbgln_if(JPEG_DEBUG, "icc marker too small");
|
||
TRY(stream.discard(bytes_to_read));
|
||
return {};
|
||
}
|
||
|
||
auto chunk_sequence_number = TRY(stream.read_u8()); // 1-based
|
||
auto number_of_chunks = TRY(stream.read_u8());
|
||
bytes_to_read -= 2;
|
||
|
||
if (!context.icc_multi_chunk_state.has_value())
|
||
context.icc_multi_chunk_state.emplace(ICCMultiChunkState { 0, TRY(FixedArray<ByteBuffer>::create(number_of_chunks)) });
|
||
auto& chunk_state = context.icc_multi_chunk_state;
|
||
|
||
u8 index {};
|
||
|
||
auto const ensure_correctness = [&]() -> ErrorOr<void> {
|
||
if (chunk_state->seen_number_of_icc_chunks >= number_of_chunks)
|
||
return Error::from_string_literal("Too many ICC chunks");
|
||
|
||
if (chunk_state->chunks.size() != number_of_chunks)
|
||
return Error::from_string_literal("Inconsistent number of total ICC chunks");
|
||
|
||
if (chunk_sequence_number == 0)
|
||
return Error::from_string_literal("ICC chunk sequence number not 1 based");
|
||
|
||
index = chunk_sequence_number - 1;
|
||
|
||
if (index >= chunk_state->chunks.size())
|
||
return Error::from_string_literal("ICC chunk sequence number larger than number of chunks");
|
||
|
||
if (!chunk_state->chunks[index].is_empty())
|
||
return Error::from_string_literal("Duplicate ICC chunk at sequence number");
|
||
|
||
return {};
|
||
};
|
||
|
||
if (auto result = ensure_correctness(); result.is_error()) {
|
||
dbgln_if(JPEG_DEBUG, "JPEG: {}", result.release_error());
|
||
TRY(stream.discard(bytes_to_read));
|
||
return {};
|
||
}
|
||
|
||
chunk_state->chunks[index] = TRY(ByteBuffer::create_zeroed(bytes_to_read));
|
||
TRY(stream.read_until_filled(chunk_state->chunks[index]));
|
||
|
||
chunk_state->seen_number_of_icc_chunks++;
|
||
|
||
if (chunk_state->seen_number_of_icc_chunks != chunk_state->chunks.size())
|
||
return {};
|
||
|
||
if (number_of_chunks == 1) {
|
||
context.icc_data = move(chunk_state->chunks[0]);
|
||
return {};
|
||
}
|
||
|
||
size_t total_size = 0;
|
||
for (auto const& chunk : chunk_state->chunks)
|
||
total_size += chunk.size();
|
||
|
||
auto icc_bytes = TRY(ByteBuffer::create_zeroed(total_size));
|
||
size_t start = 0;
|
||
for (auto const& chunk : chunk_state->chunks) {
|
||
memcpy(icc_bytes.data() + start, chunk.data(), chunk.size());
|
||
start += chunk.size();
|
||
}
|
||
|
||
context.icc_data = move(icc_bytes);
|
||
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> read_colour_encoding(JPEGStream& stream, [[maybe_unused]] JPEGLoadingContext& context, int bytes_to_read)
|
||
{
|
||
// The App 14 segment is application specific in the first JPEG standard.
|
||
// However, the Adobe implementation is globally accepted and the value of the color transform
|
||
// was latter standardized as a JPEG-1 extension.
|
||
|
||
// For the structure of the App 14 segment, see:
|
||
// https://www.pdfa.org/norm-refs/5116.DCT_Filter.pdf
|
||
// 18 Adobe Application-Specific JPEG Marker
|
||
|
||
// For the value of color_transform, see:
|
||
// https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-T.872-201206-I!!PDF-E&type=items
|
||
// 6.5.3 - APP14 marker segment for colour encoding
|
||
|
||
if (bytes_to_read < 6)
|
||
return Error::from_string_literal("App14 segment too small");
|
||
|
||
[[maybe_unused]] auto const version = TRY(stream.read_u8());
|
||
[[maybe_unused]] u16 const flag0 = TRY(stream.read_u16());
|
||
[[maybe_unused]] u16 const flag1 = TRY(stream.read_u16());
|
||
auto const color_transform = TRY(stream.read_u8());
|
||
|
||
if (bytes_to_read > 6) {
|
||
dbgln_if(JPEG_DEBUG, "Unread bytes in App14 segment: {}", bytes_to_read - 6);
|
||
TRY(stream.discard(bytes_to_read - 6));
|
||
}
|
||
|
||
switch (color_transform) {
|
||
case 0:
|
||
context.color_transform = ColorTransform::CmykOrRgb;
|
||
break;
|
||
case 1:
|
||
context.color_transform = ColorTransform::YCbCr;
|
||
break;
|
||
case 2:
|
||
context.color_transform = ColorTransform::YCCK;
|
||
break;
|
||
default:
|
||
dbgln("0x{:x} is not a specified transform flag value, ignoring", color_transform);
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> read_app_marker(JPEGStream& stream, JPEGLoadingContext& context, int app_marker_number)
|
||
{
|
||
// B.2.4.6 - Application data syntax
|
||
|
||
u16 bytes_to_read = TRY(read_effective_chunk_size(stream));
|
||
|
||
StringBuilder builder;
|
||
for (;;) {
|
||
if (bytes_to_read == 0) {
|
||
dbgln_if(JPEG_DEBUG, "app marker {} does not start with zero-terminated string", app_marker_number);
|
||
return {};
|
||
}
|
||
|
||
auto c = TRY(stream.read_u8());
|
||
bytes_to_read--;
|
||
|
||
if (c == '\0')
|
||
break;
|
||
|
||
TRY(builder.try_append(c));
|
||
}
|
||
|
||
auto app_id = TRY(builder.to_string());
|
||
|
||
if (app_marker_number == 2 && app_id == "ICC_PROFILE"sv)
|
||
return read_icc_profile(stream, context, bytes_to_read);
|
||
if (app_marker_number == 14 && app_id == "Adobe"sv)
|
||
return read_colour_encoding(stream, context, bytes_to_read);
|
||
|
||
return stream.discard(bytes_to_read);
|
||
}
|
||
|
||
static inline bool validate_luma_and_modify_context(Component const& luma, JPEGLoadingContext& context)
|
||
{
|
||
if ((luma.hsample_factor == 1 || luma.hsample_factor == 2) && (luma.vsample_factor == 1 || luma.vsample_factor == 2)) {
|
||
context.mblock_meta.hpadded_count += luma.hsample_factor == 1 ? 0 : context.mblock_meta.hcount % 2;
|
||
context.mblock_meta.vpadded_count += luma.vsample_factor == 1 ? 0 : context.mblock_meta.vcount % 2;
|
||
context.mblock_meta.padded_total = context.mblock_meta.hpadded_count * context.mblock_meta.vpadded_count;
|
||
// For easy reference to relevant sample factors.
|
||
context.hsample_factor = luma.hsample_factor;
|
||
context.vsample_factor = luma.vsample_factor;
|
||
|
||
if constexpr (JPEG_DEBUG) {
|
||
dbgln("Horizontal Subsampling Factor: {}", luma.hsample_factor);
|
||
dbgln("Vertical Subsampling Factor: {}", luma.vsample_factor);
|
||
}
|
||
|
||
return true;
|
||
}
|
||
return false;
|
||
}
|
||
|
||
static inline void set_macroblock_metadata(JPEGLoadingContext& context)
|
||
{
|
||
context.mblock_meta.hcount = (context.frame.width + 7) / 8;
|
||
context.mblock_meta.vcount = (context.frame.height + 7) / 8;
|
||
context.mblock_meta.hpadded_count = context.mblock_meta.hcount;
|
||
context.mblock_meta.vpadded_count = context.mblock_meta.vcount;
|
||
context.mblock_meta.total = context.mblock_meta.hcount * context.mblock_meta.vcount;
|
||
}
|
||
|
||
static ErrorOr<void> ensure_standard_precision(StartOfFrame const& frame)
|
||
{
|
||
// B.2.2 - Frame header syntax
|
||
// Table B.2 - Frame header parameter sizes and values
|
||
|
||
if (frame.precision == 8)
|
||
return {};
|
||
|
||
if (frame.type == StartOfFrame::FrameType::Extended_Sequential_DCT && frame.precision == 12)
|
||
return {};
|
||
|
||
if (frame.type == StartOfFrame::FrameType::Progressive_DCT && frame.precision == 12)
|
||
return {};
|
||
|
||
dbgln_if(JPEG_DEBUG, "Unsupported precision: {}, for SOF type: {}!", frame.precision, static_cast<int>(frame.type));
|
||
return Error::from_string_literal("Unsupported SOF precision.");
|
||
}
|
||
|
||
static ErrorOr<void> read_start_of_frame(JPEGStream& stream, JPEGLoadingContext& context)
|
||
{
|
||
if (context.state == JPEGLoadingContext::FrameDecoded) {
|
||
dbgln_if(JPEG_DEBUG, "SOF repeated!");
|
||
return Error::from_string_literal("SOF repeated");
|
||
}
|
||
|
||
[[maybe_unused]] u16 const bytes_to_read = TRY(read_effective_chunk_size(stream));
|
||
|
||
context.frame.precision = TRY(stream.read_u8());
|
||
|
||
TRY(ensure_standard_precision(context.frame));
|
||
|
||
context.frame.height = TRY(stream.read_u16());
|
||
context.frame.width = TRY(stream.read_u16());
|
||
if (!context.frame.width || !context.frame.height) {
|
||
dbgln_if(JPEG_DEBUG, "ERROR! Image height: {}, Image width: {}!", context.frame.height, context.frame.width);
|
||
return Error::from_string_literal("Image frame height of width null");
|
||
}
|
||
|
||
if (context.frame.width > maximum_width_for_decoded_images || context.frame.height > maximum_height_for_decoded_images) {
|
||
dbgln("This JPEG is too large for comfort: {}x{}", context.frame.width, context.frame.height);
|
||
return Error::from_string_literal("JPEG too large for comfort");
|
||
}
|
||
|
||
set_macroblock_metadata(context);
|
||
|
||
auto component_count = TRY(stream.read_u8());
|
||
if (component_count != 1 && component_count != 3 && component_count != 4) {
|
||
dbgln_if(JPEG_DEBUG, "Unsupported number of components in SOF: {}!", component_count);
|
||
return Error::from_string_literal("Unsupported number of components in SOF");
|
||
}
|
||
|
||
for (u8 i = 0; i < component_count; i++) {
|
||
Component component;
|
||
component.id = TRY(stream.read_u8());
|
||
component.index = i;
|
||
|
||
u8 subsample_factors = TRY(stream.read_u8());
|
||
component.hsample_factor = subsample_factors >> 4;
|
||
component.vsample_factor = subsample_factors & 0x0F;
|
||
|
||
if (i == 0) {
|
||
// By convention, downsampling is applied only on chroma components. So we should
|
||
// hope to see the maximum sampling factor in the luma component.
|
||
if (!validate_luma_and_modify_context(component, context)) {
|
||
dbgln_if(JPEG_DEBUG, "Unsupported luma subsampling factors: horizontal: {}, vertical: {}",
|
||
component.hsample_factor,
|
||
component.vsample_factor);
|
||
return Error::from_string_literal("Unsupported luma subsampling factors");
|
||
}
|
||
} else {
|
||
if (component.hsample_factor != 1 || component.vsample_factor != 1) {
|
||
dbgln_if(JPEG_DEBUG, "Unsupported chroma subsampling factors: horizontal: {}, vertical: {}",
|
||
component.hsample_factor,
|
||
component.vsample_factor);
|
||
return Error::from_string_literal("Unsupported chroma subsampling factors");
|
||
}
|
||
}
|
||
|
||
component.quantization_table_id = TRY(stream.read_u8());
|
||
|
||
context.components.append(move(component));
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> read_quantization_table(JPEGStream& stream, JPEGLoadingContext& context)
|
||
{
|
||
// B.2.4.1 - Quantization table-specification syntax
|
||
|
||
u16 bytes_to_read = TRY(read_effective_chunk_size(stream));
|
||
|
||
while (bytes_to_read > 0) {
|
||
u8 const info_byte = TRY(stream.read_u8());
|
||
u8 const element_unit_hint = info_byte >> 4;
|
||
if (element_unit_hint > 1) {
|
||
dbgln_if(JPEG_DEBUG, "Unsupported unit hint in quantization table: {}!", element_unit_hint);
|
||
return Error::from_string_literal("Unsupported unit hint in quantization table");
|
||
}
|
||
u8 const table_id = info_byte & 0x0F;
|
||
|
||
if (table_id > 3) {
|
||
dbgln_if(JPEG_DEBUG, "Unsupported quantization table id: {}!", table_id);
|
||
return Error::from_string_literal("Unsupported quantization table id");
|
||
}
|
||
|
||
auto& maybe_table = context.quantization_tables[table_id];
|
||
|
||
if (!maybe_table.has_value())
|
||
maybe_table = Array<u16, 64> {};
|
||
|
||
auto& table = maybe_table.value();
|
||
|
||
for (int i = 0; i < 64; i++) {
|
||
if (element_unit_hint == 0)
|
||
table[zigzag_map[i]] = TRY(stream.read_u8());
|
||
else
|
||
table[zigzag_map[i]] = TRY(stream.read_u16());
|
||
}
|
||
|
||
bytes_to_read -= 1 + (element_unit_hint == 0 ? 64 : 128);
|
||
}
|
||
if (bytes_to_read != 0) {
|
||
dbgln_if(JPEG_DEBUG, "Invalid length for one or more quantization tables!");
|
||
return Error::from_string_literal("Invalid length for one or more quantization tables");
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> skip_segment(JPEGStream& stream)
|
||
{
|
||
u16 bytes_to_skip = TRY(stream.read_u16()) - 2;
|
||
TRY(stream.discard(bytes_to_skip));
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> dequantize(JPEGLoadingContext& context, Vector<Macroblock>& macroblocks)
|
||
{
|
||
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
|
||
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
|
||
for (u32 i = 0; i < context.components.size(); i++) {
|
||
auto const& component = context.components[i];
|
||
|
||
if (!context.quantization_tables[component.quantization_table_id].has_value()) {
|
||
dbgln_if(JPEG_DEBUG, "Unknown quantization table id: {}!", component.quantization_table_id);
|
||
return Error::from_string_literal("Unknown quantization table id");
|
||
}
|
||
|
||
auto const& table = context.quantization_tables[component.quantization_table_id].value();
|
||
|
||
for (u32 vfactor_i = 0; vfactor_i < component.vsample_factor; vfactor_i++) {
|
||
for (u32 hfactor_i = 0; hfactor_i < component.hsample_factor; hfactor_i++) {
|
||
u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor);
|
||
Macroblock& block = macroblocks[macroblock_index];
|
||
auto* block_component = get_component(block, i);
|
||
for (u32 k = 0; k < 64; k++)
|
||
block_component[k] *= table[k];
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
static void inverse_dct(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
|
||
{
|
||
static float const m0 = 2.0f * AK::cos(1.0f / 16.0f * 2.0f * AK::Pi<float>);
|
||
static float const m1 = 2.0f * AK::cos(2.0f / 16.0f * 2.0f * AK::Pi<float>);
|
||
static float const m3 = 2.0f * AK::cos(2.0f / 16.0f * 2.0f * AK::Pi<float>);
|
||
static float const m5 = 2.0f * AK::cos(3.0f / 16.0f * 2.0f * AK::Pi<float>);
|
||
static float const m2 = m0 - m5;
|
||
static float const m4 = m0 + m5;
|
||
static float const s0 = AK::cos(0.0f / 16.0f * AK::Pi<float>) * AK::rsqrt(8.0f);
|
||
static float const s1 = AK::cos(1.0f / 16.0f * AK::Pi<float>) / 2.0f;
|
||
static float const s2 = AK::cos(2.0f / 16.0f * AK::Pi<float>) / 2.0f;
|
||
static float const s3 = AK::cos(3.0f / 16.0f * AK::Pi<float>) / 2.0f;
|
||
static float const s4 = AK::cos(4.0f / 16.0f * AK::Pi<float>) / 2.0f;
|
||
static float const s5 = AK::cos(5.0f / 16.0f * AK::Pi<float>) / 2.0f;
|
||
static float const s6 = AK::cos(6.0f / 16.0f * AK::Pi<float>) / 2.0f;
|
||
static float const s7 = AK::cos(7.0f / 16.0f * AK::Pi<float>) / 2.0f;
|
||
|
||
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
|
||
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
|
||
for (u32 component_i = 0; component_i < context.components.size(); component_i++) {
|
||
auto& component = context.components[component_i];
|
||
for (u8 vfactor_i = 0; vfactor_i < component.vsample_factor; vfactor_i++) {
|
||
for (u8 hfactor_i = 0; hfactor_i < component.hsample_factor; hfactor_i++) {
|
||
u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor);
|
||
Macroblock& block = macroblocks[macroblock_index];
|
||
auto* block_component = get_component(block, component_i);
|
||
for (u32 k = 0; k < 8; ++k) {
|
||
float const g0 = block_component[0 * 8 + k] * s0;
|
||
float const g1 = block_component[4 * 8 + k] * s4;
|
||
float const g2 = block_component[2 * 8 + k] * s2;
|
||
float const g3 = block_component[6 * 8 + k] * s6;
|
||
float const g4 = block_component[5 * 8 + k] * s5;
|
||
float const g5 = block_component[1 * 8 + k] * s1;
|
||
float const g6 = block_component[7 * 8 + k] * s7;
|
||
float const g7 = block_component[3 * 8 + k] * s3;
|
||
|
||
float const f0 = g0;
|
||
float const f1 = g1;
|
||
float const f2 = g2;
|
||
float const f3 = g3;
|
||
float const f4 = g4 - g7;
|
||
float const f5 = g5 + g6;
|
||
float const f6 = g5 - g6;
|
||
float const f7 = g4 + g7;
|
||
|
||
float const e0 = f0;
|
||
float const e1 = f1;
|
||
float const e2 = f2 - f3;
|
||
float const e3 = f2 + f3;
|
||
float const e4 = f4;
|
||
float const e5 = f5 - f7;
|
||
float const e6 = f6;
|
||
float const e7 = f5 + f7;
|
||
float const e8 = f4 + f6;
|
||
|
||
float const d0 = e0;
|
||
float const d1 = e1;
|
||
float const d2 = e2 * m1;
|
||
float const d3 = e3;
|
||
float const d4 = e4 * m2;
|
||
float const d5 = e5 * m3;
|
||
float const d6 = e6 * m4;
|
||
float const d7 = e7;
|
||
float const d8 = e8 * m5;
|
||
|
||
float const c0 = d0 + d1;
|
||
float const c1 = d0 - d1;
|
||
float const c2 = d2 - d3;
|
||
float const c3 = d3;
|
||
float const c4 = d4 + d8;
|
||
float const c5 = d5 + d7;
|
||
float const c6 = d6 - d8;
|
||
float const c7 = d7;
|
||
float const c8 = c5 - c6;
|
||
|
||
float const b0 = c0 + c3;
|
||
float const b1 = c1 + c2;
|
||
float const b2 = c1 - c2;
|
||
float const b3 = c0 - c3;
|
||
float const b4 = c4 - c8;
|
||
float const b5 = c8;
|
||
float const b6 = c6 - c7;
|
||
float const b7 = c7;
|
||
|
||
block_component[0 * 8 + k] = b0 + b7;
|
||
block_component[1 * 8 + k] = b1 + b6;
|
||
block_component[2 * 8 + k] = b2 + b5;
|
||
block_component[3 * 8 + k] = b3 + b4;
|
||
block_component[4 * 8 + k] = b3 - b4;
|
||
block_component[5 * 8 + k] = b2 - b5;
|
||
block_component[6 * 8 + k] = b1 - b6;
|
||
block_component[7 * 8 + k] = b0 - b7;
|
||
}
|
||
for (u32 l = 0; l < 8; ++l) {
|
||
float const g0 = block_component[l * 8 + 0] * s0;
|
||
float const g1 = block_component[l * 8 + 4] * s4;
|
||
float const g2 = block_component[l * 8 + 2] * s2;
|
||
float const g3 = block_component[l * 8 + 6] * s6;
|
||
float const g4 = block_component[l * 8 + 5] * s5;
|
||
float const g5 = block_component[l * 8 + 1] * s1;
|
||
float const g6 = block_component[l * 8 + 7] * s7;
|
||
float const g7 = block_component[l * 8 + 3] * s3;
|
||
|
||
float const f0 = g0;
|
||
float const f1 = g1;
|
||
float const f2 = g2;
|
||
float const f3 = g3;
|
||
float const f4 = g4 - g7;
|
||
float const f5 = g5 + g6;
|
||
float const f6 = g5 - g6;
|
||
float const f7 = g4 + g7;
|
||
|
||
float const e0 = f0;
|
||
float const e1 = f1;
|
||
float const e2 = f2 - f3;
|
||
float const e3 = f2 + f3;
|
||
float const e4 = f4;
|
||
float const e5 = f5 - f7;
|
||
float const e6 = f6;
|
||
float const e7 = f5 + f7;
|
||
float const e8 = f4 + f6;
|
||
|
||
float const d0 = e0;
|
||
float const d1 = e1;
|
||
float const d2 = e2 * m1;
|
||
float const d3 = e3;
|
||
float const d4 = e4 * m2;
|
||
float const d5 = e5 * m3;
|
||
float const d6 = e6 * m4;
|
||
float const d7 = e7;
|
||
float const d8 = e8 * m5;
|
||
|
||
float const c0 = d0 + d1;
|
||
float const c1 = d0 - d1;
|
||
float const c2 = d2 - d3;
|
||
float const c3 = d3;
|
||
float const c4 = d4 + d8;
|
||
float const c5 = d5 + d7;
|
||
float const c6 = d6 - d8;
|
||
float const c7 = d7;
|
||
float const c8 = c5 - c6;
|
||
|
||
float const b0 = c0 + c3;
|
||
float const b1 = c1 + c2;
|
||
float const b2 = c1 - c2;
|
||
float const b3 = c0 - c3;
|
||
float const b4 = c4 - c8;
|
||
float const b5 = c8;
|
||
float const b6 = c6 - c7;
|
||
float const b7 = c7;
|
||
|
||
block_component[l * 8 + 0] = b0 + b7;
|
||
block_component[l * 8 + 1] = b1 + b6;
|
||
block_component[l * 8 + 2] = b2 + b5;
|
||
block_component[l * 8 + 3] = b3 + b4;
|
||
block_component[l * 8 + 4] = b3 - b4;
|
||
block_component[l * 8 + 5] = b2 - b5;
|
||
block_component[l * 8 + 6] = b1 - b6;
|
||
block_component[l * 8 + 7] = b0 - b7;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
// F.2.1.5 - Inverse DCT (IDCT)
|
||
auto const level_shift = 1 << (context.frame.precision - 1);
|
||
auto const max_value = (1 << context.frame.precision) - 1;
|
||
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
|
||
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
|
||
for (u8 vfactor_i = 0; vfactor_i < context.vsample_factor; ++vfactor_i) {
|
||
for (u8 hfactor_i = 0; hfactor_i < context.hsample_factor; ++hfactor_i) {
|
||
u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
|
||
for (u8 i = 0; i < 8; ++i) {
|
||
for (u8 j = 0; j < 8; ++j) {
|
||
|
||
// FIXME: This just truncate all coefficients, it's an easy way to support (read hack)
|
||
// 12 bits JPEGs without rewriting all color transformations.
|
||
auto const clamp_to_8_bits = [&](u16 color) -> u8 {
|
||
if (context.frame.precision == 8)
|
||
return static_cast<u8>(color);
|
||
return static_cast<u8>(color >> 4);
|
||
};
|
||
|
||
macroblocks[mb_index].r[i * 8 + j] = clamp_to_8_bits(clamp(macroblocks[mb_index].r[i * 8 + j] + level_shift, 0, max_value));
|
||
macroblocks[mb_index].g[i * 8 + j] = clamp_to_8_bits(clamp(macroblocks[mb_index].g[i * 8 + j] + level_shift, 0, max_value));
|
||
macroblocks[mb_index].b[i * 8 + j] = clamp_to_8_bits(clamp(macroblocks[mb_index].b[i * 8 + j] + level_shift, 0, max_value));
|
||
macroblocks[mb_index].k[i * 8 + j] = clamp_to_8_bits(clamp(macroblocks[mb_index].k[i * 8 + j] + level_shift, 0, max_value));
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
static void ycbcr_to_rgb(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
|
||
{
|
||
// Conversion from YCbCr to RGB isn't specified in the first JPEG specification but in the JFIF extension:
|
||
// See: https://www.itu.int/rec/dologin_pub.asp?lang=f&id=T-REC-T.871-201105-I!!PDF-E&type=items
|
||
// 7 - Conversion to and from RGB
|
||
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
|
||
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
|
||
u32 const chroma_block_index = vcursor * context.mblock_meta.hpadded_count + hcursor;
|
||
Macroblock const& chroma = macroblocks[chroma_block_index];
|
||
// Overflows are intentional.
|
||
for (u8 vfactor_i = context.vsample_factor - 1; vfactor_i < context.vsample_factor; --vfactor_i) {
|
||
for (u8 hfactor_i = context.hsample_factor - 1; hfactor_i < context.hsample_factor; --hfactor_i) {
|
||
u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
|
||
auto* y = macroblocks[macroblock_index].y;
|
||
auto* cb = macroblocks[macroblock_index].cb;
|
||
auto* cr = macroblocks[macroblock_index].cr;
|
||
for (u8 i = 7; i < 8; --i) {
|
||
for (u8 j = 7; j < 8; --j) {
|
||
u8 const pixel = i * 8 + j;
|
||
u32 const chroma_pxrow = (i / context.vsample_factor) + 4 * vfactor_i;
|
||
u32 const chroma_pxcol = (j / context.hsample_factor) + 4 * hfactor_i;
|
||
u32 const chroma_pixel = chroma_pxrow * 8 + chroma_pxcol;
|
||
int r = y[pixel] + 1.402f * (chroma.cr[chroma_pixel] - 128);
|
||
int g = y[pixel] - 0.3441f * (chroma.cb[chroma_pixel] - 128) - 0.7141f * (chroma.cr[chroma_pixel] - 128);
|
||
int b = y[pixel] + 1.772f * (chroma.cb[chroma_pixel] - 128);
|
||
y[pixel] = clamp(r, 0, 255);
|
||
cb[pixel] = clamp(g, 0, 255);
|
||
cr[pixel] = clamp(b, 0, 255);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
static void invert_colors_for_adobe_images(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
|
||
{
|
||
if (!context.color_transform.has_value())
|
||
return;
|
||
|
||
// From libjpeg-turbo's libjpeg.txt:
|
||
// https://github.com/libjpeg-turbo/libjpeg-turbo/blob/main/libjpeg.txt
|
||
// CAUTION: it appears that Adobe Photoshop writes inverted data in CMYK JPEG
|
||
// files: 0 represents 100% ink coverage, rather than 0% ink as you'd expect.
|
||
// This is arguably a bug in Photoshop, but if you need to work with Photoshop
|
||
// CMYK files, you will have to deal with it in your application.
|
||
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
|
||
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
|
||
for (u8 vfactor_i = 0; vfactor_i < context.vsample_factor; ++vfactor_i) {
|
||
for (u8 hfactor_i = 0; hfactor_i < context.hsample_factor; ++hfactor_i) {
|
||
u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
|
||
for (u8 i = 0; i < 8; ++i) {
|
||
for (u8 j = 0; j < 8; ++j) {
|
||
macroblocks[mb_index].r[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].r[i * 8 + j];
|
||
macroblocks[mb_index].g[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].g[i * 8 + j];
|
||
macroblocks[mb_index].b[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].b[i * 8 + j];
|
||
macroblocks[mb_index].k[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].k[i * 8 + j];
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
static void cmyk_to_rgb(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
|
||
{
|
||
invert_colors_for_adobe_images(context, macroblocks);
|
||
|
||
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
|
||
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
|
||
for (u8 vfactor_i = context.vsample_factor - 1; vfactor_i < context.vsample_factor; --vfactor_i) {
|
||
for (u8 hfactor_i = context.hsample_factor - 1; hfactor_i < context.hsample_factor; --hfactor_i) {
|
||
u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
|
||
auto* c = macroblocks[mb_index].y;
|
||
auto* m = macroblocks[mb_index].cb;
|
||
auto* y = macroblocks[mb_index].cr;
|
||
auto* k = macroblocks[mb_index].k;
|
||
for (u8 i = 0; i < 8; ++i) {
|
||
for (u8 j = 0; j < 8; ++j) {
|
||
u8 const pixel = i * 8 + j;
|
||
|
||
static constexpr auto max_value = NumericLimits<u8>::max();
|
||
|
||
auto const black_component = max_value - k[pixel];
|
||
int const r = ((max_value - c[pixel]) * black_component) / max_value;
|
||
int const g = ((max_value - m[pixel]) * black_component) / max_value;
|
||
int const b = ((max_value - y[pixel]) * black_component) / max_value;
|
||
|
||
c[pixel] = clamp(r, 0, max_value);
|
||
m[pixel] = clamp(g, 0, max_value);
|
||
y[pixel] = clamp(b, 0, max_value);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
static void ycck_to_rgb(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
|
||
{
|
||
// 7 - Conversions between colour encodings
|
||
// YCCK is obtained from CMYK by converting the CMY channels to YCC channel.
|
||
|
||
// To convert back into RGB, we only need the 3 first components, which are baseline YCbCr
|
||
ycbcr_to_rgb(context, macroblocks);
|
||
|
||
// RGB to CMYK, as mentioned in https://www.smcm.iqfr.csic.es/docs/intel/ipp/ipp_manual/IPPI/ippi_ch15/functn_YCCKToCMYK_JPEG.htm#functn_YCCKToCMYK_JPEG
|
||
for (u32 vcursor = 0; vcursor < context.mblock_meta.vcount; vcursor += context.vsample_factor) {
|
||
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
|
||
for (u8 vfactor_i = 0; vfactor_i < context.vsample_factor; ++vfactor_i) {
|
||
for (u8 hfactor_i = 0; hfactor_i < context.hsample_factor; ++hfactor_i) {
|
||
u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hcursor + hfactor_i);
|
||
for (u8 i = 0; i < 8; ++i) {
|
||
for (u8 j = 0; j < 8; ++j) {
|
||
macroblocks[mb_index].r[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].r[i * 8 + j];
|
||
macroblocks[mb_index].g[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].g[i * 8 + j];
|
||
macroblocks[mb_index].b[i * 8 + j] = NumericLimits<u8>::max() - macroblocks[mb_index].b[i * 8 + j];
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
cmyk_to_rgb(context, macroblocks);
|
||
}
|
||
|
||
static ErrorOr<void> handle_color_transform(JPEGLoadingContext const& context, Vector<Macroblock>& macroblocks)
|
||
{
|
||
// Note: This is non-standard but some encoder still add the App14 segment for grayscale images.
|
||
// So let's ignore the color transform value if we only have one component.
|
||
if (context.color_transform.has_value() && context.components.size() != 1) {
|
||
// https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-T.872-201206-I!!PDF-E&type=items
|
||
// 6.5.3 - APP14 marker segment for colour encoding
|
||
|
||
switch (*context.color_transform) {
|
||
case ColorTransform::CmykOrRgb:
|
||
if (context.components.size() == 4) {
|
||
cmyk_to_rgb(context, macroblocks);
|
||
} else if (context.components.size() == 3) {
|
||
// Note: components.size() == 3 means that we have an RGB image, so no color transformation is needed.
|
||
} else {
|
||
return Error::from_string_literal("Wrong number of components for CMYK or RGB, aborting.");
|
||
}
|
||
break;
|
||
case ColorTransform::YCbCr:
|
||
ycbcr_to_rgb(context, macroblocks);
|
||
break;
|
||
case ColorTransform::YCCK:
|
||
ycck_to_rgb(context, macroblocks);
|
||
break;
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
// No App14 segment is present, assuming :
|
||
// - 1 components means grayscale
|
||
// - 3 components means YCbCr
|
||
// - 4 components means CMYK
|
||
if (context.components.size() == 4)
|
||
cmyk_to_rgb(context, macroblocks);
|
||
if (context.components.size() == 3)
|
||
ycbcr_to_rgb(context, macroblocks);
|
||
|
||
if (context.components.size() == 1) {
|
||
// With Cb and Cr being equal to zero, this function assign the Y
|
||
// value (luminosity) to R, G and B. Providing a proper conversion
|
||
// from grayscale to RGB.
|
||
ycbcr_to_rgb(context, macroblocks);
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> compose_bitmap(JPEGLoadingContext& context, Vector<Macroblock> const& macroblocks)
|
||
{
|
||
context.bitmap = TRY(Bitmap::create(BitmapFormat::BGRx8888, { context.frame.width, context.frame.height }));
|
||
|
||
for (u32 y = context.frame.height - 1; y < context.frame.height; y--) {
|
||
u32 const block_row = y / 8;
|
||
u32 const pixel_row = y % 8;
|
||
for (u32 x = 0; x < context.frame.width; x++) {
|
||
u32 const block_column = x / 8;
|
||
auto& block = macroblocks[block_row * context.mblock_meta.hpadded_count + block_column];
|
||
u32 const pixel_column = x % 8;
|
||
u32 const pixel_index = pixel_row * 8 + pixel_column;
|
||
Color const color { (u8)block.y[pixel_index], (u8)block.cb[pixel_index], (u8)block.cr[pixel_index] };
|
||
context.bitmap->set_pixel(x, y, color);
|
||
}
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
static bool is_app_marker(Marker const marker)
|
||
{
|
||
return marker >= JPEG_APPN0 && marker <= JPEG_APPN15;
|
||
}
|
||
|
||
static bool is_miscellaneous_or_table_marker(Marker const marker)
|
||
{
|
||
// B.2.4 - Table-specification and miscellaneous marker segment syntax
|
||
// See also B.6 - Summary: Figure B.17 – Flow of marker segment
|
||
|
||
bool const is_misc = marker == JPEG_COM || marker == JPEG_DRI || is_app_marker(marker);
|
||
bool const is_table = marker == JPEG_DQT || marker == JPEG_DAC || marker == JPEG_DHT;
|
||
|
||
return is_misc || is_table;
|
||
}
|
||
|
||
static ErrorOr<void> handle_miscellaneous_or_table(JPEGStream& stream, JPEGLoadingContext& context, Marker const marker)
|
||
{
|
||
if (is_app_marker(marker)) {
|
||
TRY(read_app_marker(stream, context, marker - JPEG_APPN0));
|
||
return {};
|
||
}
|
||
|
||
switch (marker) {
|
||
case JPEG_COM:
|
||
case JPEG_DAC:
|
||
dbgln_if(JPEG_DEBUG, "TODO: implement marker \"{:x}\"", marker);
|
||
if (auto result = skip_segment(stream); result.is_error()) {
|
||
dbgln_if(JPEG_DEBUG, "Error skipping marker: {:x}!", marker);
|
||
return result.release_error();
|
||
}
|
||
break;
|
||
case JPEG_DHT:
|
||
TRY(read_huffman_table(stream, context));
|
||
break;
|
||
case JPEG_DQT:
|
||
TRY(read_quantization_table(stream, context));
|
||
break;
|
||
case JPEG_DRI:
|
||
TRY(read_restart_interval(stream, context));
|
||
break;
|
||
default:
|
||
dbgln("Unexpected marker: {:x}", marker);
|
||
VERIFY_NOT_REACHED();
|
||
}
|
||
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<void> parse_header(JPEGStream& stream, JPEGLoadingContext& context)
|
||
{
|
||
auto marker = TRY(read_marker_at_cursor(stream));
|
||
if (marker != JPEG_SOI) {
|
||
dbgln_if(JPEG_DEBUG, "SOI not found: {:x}!", marker);
|
||
return Error::from_string_literal("SOI not found");
|
||
}
|
||
for (;;) {
|
||
marker = TRY(read_marker_at_cursor(stream));
|
||
|
||
if (is_miscellaneous_or_table_marker(marker)) {
|
||
TRY(handle_miscellaneous_or_table(stream, context, marker));
|
||
continue;
|
||
}
|
||
|
||
// Set frame type if the marker marks a new frame.
|
||
if (is_frame_marker(marker))
|
||
context.frame.type = static_cast<StartOfFrame::FrameType>(marker & 0xF);
|
||
|
||
switch (marker) {
|
||
case JPEG_RST0:
|
||
case JPEG_RST1:
|
||
case JPEG_RST2:
|
||
case JPEG_RST3:
|
||
case JPEG_RST4:
|
||
case JPEG_RST5:
|
||
case JPEG_RST6:
|
||
case JPEG_RST7:
|
||
case JPEG_SOI:
|
||
case JPEG_EOI:
|
||
dbgln_if(JPEG_DEBUG, "Unexpected marker {:x}!", marker);
|
||
return Error::from_string_literal("Unexpected marker");
|
||
case JPEG_SOF0:
|
||
case JPEG_SOF1:
|
||
case JPEG_SOF2:
|
||
TRY(read_start_of_frame(stream, context));
|
||
context.state = JPEGLoadingContext::FrameDecoded;
|
||
return {};
|
||
default:
|
||
if (auto result = skip_segment(stream); result.is_error()) {
|
||
dbgln_if(JPEG_DEBUG, "Error skipping marker: {:x}!", marker);
|
||
return result.release_error();
|
||
}
|
||
break;
|
||
}
|
||
}
|
||
|
||
VERIFY_NOT_REACHED();
|
||
}
|
||
|
||
static ErrorOr<void> decode_header(JPEGLoadingContext& context)
|
||
{
|
||
VERIFY(context.state < JPEGLoadingContext::State::HeaderDecoded);
|
||
TRY(parse_header(context.stream, context));
|
||
|
||
if constexpr (JPEG_DEBUG) {
|
||
dbgln("Image width: {}", context.frame.width);
|
||
dbgln("Image height: {}", context.frame.height);
|
||
dbgln("Macroblocks in a row: {}", context.mblock_meta.hpadded_count);
|
||
dbgln("Macroblocks in a column: {}", context.mblock_meta.vpadded_count);
|
||
dbgln("Macroblock meta padded total: {}", context.mblock_meta.padded_total);
|
||
}
|
||
|
||
context.state = JPEGLoadingContext::State::HeaderDecoded;
|
||
return {};
|
||
}
|
||
|
||
static ErrorOr<Vector<Macroblock>> construct_macroblocks(JPEGLoadingContext& context)
|
||
{
|
||
// B.6 - Summary
|
||
// See: Figure B.16 – Flow of compressed data syntax
|
||
// This function handles the "Multi-scan" loop.
|
||
|
||
Vector<Macroblock> macroblocks;
|
||
TRY(macroblocks.try_resize(context.mblock_meta.padded_total));
|
||
|
||
Marker marker = TRY(read_marker_at_cursor(context.stream));
|
||
while (true) {
|
||
if (is_miscellaneous_or_table_marker(marker)) {
|
||
TRY(handle_miscellaneous_or_table(context.stream, context, marker));
|
||
} else if (marker == JPEG_SOS) {
|
||
TRY(read_start_of_scan(context.stream, context));
|
||
TRY(decode_huffman_stream(context, macroblocks));
|
||
} else if (marker == JPEG_EOI) {
|
||
return macroblocks;
|
||
} else {
|
||
dbgln_if(JPEG_DEBUG, "Unexpected marker {:x}!", marker);
|
||
return Error::from_string_literal("Unexpected marker");
|
||
}
|
||
|
||
marker = TRY(read_marker_at_cursor(context.stream));
|
||
}
|
||
}
|
||
|
||
static ErrorOr<void> decode_jpeg(JPEGLoadingContext& context)
|
||
{
|
||
auto macroblocks = TRY(construct_macroblocks(context));
|
||
TRY(dequantize(context, macroblocks));
|
||
inverse_dct(context, macroblocks);
|
||
TRY(handle_color_transform(context, macroblocks));
|
||
TRY(compose_bitmap(context, macroblocks));
|
||
return {};
|
||
}
|
||
|
||
JPEGImageDecoderPlugin::JPEGImageDecoderPlugin(NonnullOwnPtr<FixedMemoryStream> stream)
|
||
{
|
||
m_context = JPEGLoadingContext::create(move(stream)).release_value_but_fixme_should_propagate_errors();
|
||
}
|
||
|
||
JPEGImageDecoderPlugin::~JPEGImageDecoderPlugin() = default;
|
||
|
||
IntSize JPEGImageDecoderPlugin::size()
|
||
{
|
||
return { m_context->frame.width, m_context->frame.height };
|
||
}
|
||
|
||
bool JPEGImageDecoderPlugin::sniff(ReadonlyBytes data)
|
||
{
|
||
return data.size() > 3
|
||
&& data.data()[0] == 0xFF
|
||
&& data.data()[1] == 0xD8
|
||
&& data.data()[2] == 0xFF;
|
||
}
|
||
|
||
ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> JPEGImageDecoderPlugin::create(ReadonlyBytes data)
|
||
{
|
||
auto stream = TRY(try_make<FixedMemoryStream>(data));
|
||
auto plugin = TRY(adopt_nonnull_own_or_enomem(new (nothrow) JPEGImageDecoderPlugin(move(stream))));
|
||
TRY(decode_header(*plugin->m_context));
|
||
return plugin;
|
||
}
|
||
|
||
ErrorOr<ImageFrameDescriptor> JPEGImageDecoderPlugin::frame(size_t index, Optional<IntSize>)
|
||
{
|
||
if (index > 0)
|
||
return Error::from_string_literal("JPEGImageDecoderPlugin: Invalid frame index");
|
||
|
||
if (m_context->state == JPEGLoadingContext::State::Error)
|
||
return Error::from_string_literal("JPEGImageDecoderPlugin: Decoding failed");
|
||
|
||
if (m_context->state < JPEGLoadingContext::State::BitmapDecoded) {
|
||
if (auto result = decode_jpeg(*m_context); result.is_error()) {
|
||
m_context->state = JPEGLoadingContext::State::Error;
|
||
return result.release_error();
|
||
}
|
||
m_context->state = JPEGLoadingContext::State::BitmapDecoded;
|
||
}
|
||
|
||
return ImageFrameDescriptor { m_context->bitmap, 0 };
|
||
}
|
||
|
||
ErrorOr<Optional<ReadonlyBytes>> JPEGImageDecoderPlugin::icc_data()
|
||
{
|
||
if (m_context->icc_data.has_value())
|
||
return *m_context->icc_data;
|
||
return OptionalNone {};
|
||
}
|
||
|
||
}
|