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https://github.com/RGBCube/serenity
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LibGfx/TGA: Simplify the code by converting it to use AK::Stream
The conversion to AK::Stream makes everything much more straightforward and understandable now, because we remove the custom reader we had. Because AK::Stream is more tested, it means that the code should be now more robust against bugs as well.
This commit is contained in:
Liav A
Sam Atkins
parent
18b7ddd0b5
commit
dc612231f5
2 changed files with 79 additions and 171 deletions
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@ -4,9 +4,11 @@
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/MemoryStream.h>
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#include <AK/Span.h>
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#include <AK/StdLibExtraDetails.h>
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#include <AK/String.h>
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#include <AK/Traits.h>
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#include <LibGfx/ImageFormats/TGALoader.h>
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namespace Gfx {
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@ -37,134 +39,30 @@ struct [[gnu::packed]] TGAHeader {
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u8 bits_per_pixel;
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u8 image_descriptor;
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};
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static_assert(sizeof(TGAHeader) == 18);
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union [[gnu::packed]] TGAPixel {
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struct TGAColor {
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u8 blue;
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u8 green;
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u8 red;
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u8 alpha;
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} components;
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}
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u32 data;
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template<>
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struct AK::Traits<Gfx::TGAHeader> : public GenericTraits<Gfx::TGAHeader> {
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static constexpr bool is_trivially_serializable() { return true; }
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};
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struct TGAPixelPacket {
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bool raw;
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u8 pixels_count;
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};
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static_assert(AssertSize<TGAPixel, 4>());
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class TGAReader {
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public:
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TGAReader(ReadonlyBytes data)
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: m_data(move(data))
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{
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}
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TGAReader(ReadonlyBytes data, size_t index)
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: m_data(move(data))
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, m_index(index)
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{
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}
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ALWAYS_INLINE u8 read_u8()
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{
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u8 value = m_data[m_index];
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m_index++;
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return value;
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}
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ALWAYS_INLINE i8 read_i8()
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{
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return static_cast<i8>(read_u8());
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}
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ALWAYS_INLINE u16 read_u16()
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{
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return read_u8() | read_u8() << 8;
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}
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ALWAYS_INLINE i16 read_i16()
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{
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return read_i8() | read_i8() << 8;
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}
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ALWAYS_INLINE u32 read_u32()
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{
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return read_u16() | read_u16() << 16;
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}
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ALWAYS_INLINE i32 read_i32()
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{
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return read_i16() | read_i16() << 16;
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}
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ALWAYS_INLINE TGAPixelPacket read_packet_type()
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{
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auto pixel_packet_type = read_u8();
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auto pixel_packet = TGAPixelPacket();
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pixel_packet.raw = !(pixel_packet_type & 0x80);
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pixel_packet.pixels_count = (pixel_packet_type & 0x7f);
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// NOTE: Run-length-encoded/Raw pixel packets cannot encode zero pixels,
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// so value 0 stands for 1 pixel, 1 stands for 2, etc...
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pixel_packet.pixels_count++;
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return pixel_packet;
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}
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ALWAYS_INLINE TGAPixel read_pixel(u8 bits_per_pixel)
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{
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auto pixel = TGAPixel();
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switch (bits_per_pixel) {
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case 24:
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pixel.components.blue = read_u8();
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pixel.components.green = read_u8();
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pixel.components.red = read_u8();
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pixel.components.alpha = 0xFF;
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return pixel;
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case 32:
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pixel.components.blue = read_u8();
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pixel.components.green = read_u8();
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pixel.components.red = read_u8();
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pixel.components.alpha = read_u8();
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return pixel;
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default:
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VERIFY_NOT_REACHED();
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}
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}
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size_t index() const
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{
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return m_index;
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}
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ReadonlyBytes data() const
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{
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return m_data;
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}
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private:
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ReadonlyBytes m_data;
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size_t m_index { 0 };
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};
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namespace Gfx {
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struct TGALoadingContext {
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TGALoadingContext(FixedMemoryStream stream)
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: stream(move(stream))
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{
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}
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FixedMemoryStream stream;
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TGAHeader header {};
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OwnPtr<TGAReader> reader = { nullptr };
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RefPtr<Gfx::Bitmap> bitmap;
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};
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TGAImageDecoderPlugin::TGAImageDecoderPlugin(u8 const* file_data, size_t file_size)
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TGAImageDecoderPlugin::TGAImageDecoderPlugin(NonnullOwnPtr<TGALoadingContext> context)
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: m_context(move(context))
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{
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m_context = make<TGALoadingContext>();
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m_context->reader = make<TGAReader>(ReadonlyBytes { file_data, file_size });
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}
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TGAImageDecoderPlugin::~TGAImageDecoderPlugin() = default;
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@ -174,55 +72,68 @@ IntSize TGAImageDecoderPlugin::size()
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return IntSize { m_context->header.width, m_context->header.height };
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}
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static ErrorOr<void> ensure_header_validity(TGAHeader const& header, size_t whole_image_stream_size)
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{
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auto bytes_remaining = whole_image_stream_size - sizeof(TGAHeader);
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if ((header.bits_per_pixel % 8) != 0 || header.bits_per_pixel < 8 || header.bits_per_pixel > 32)
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return Error::from_string_literal("Invalid bit depth");
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if (header.data_type_code == TGADataType::UncompressedRGB && bytes_remaining < static_cast<u64>(header.width) * header.height * (header.bits_per_pixel / 8))
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return Error::from_string_literal("Not enough data to read an image with the expected size");
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return {};
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}
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ErrorOr<void> TGAImageDecoderPlugin::decode_tga_header()
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{
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auto& reader = m_context->reader;
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if (reader->data().size() < sizeof(TGAHeader))
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return Error::from_string_literal("Not enough data to be a TGA image");
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m_context->header.id_length = reader->read_u8();
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m_context->header.color_map_type = reader->read_u8();
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m_context->header.data_type_code = static_cast<TGADataType>(reader->read_u8());
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m_context->header.color_map_origin = reader->read_i16();
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m_context->header.color_map_length = reader->read_i16();
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m_context->header.color_map_depth = reader->read_u8();
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m_context->header.x_origin = reader->read_i16();
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m_context->header.y_origin = reader->read_i16();
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m_context->header.width = reader->read_u16();
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m_context->header.height = reader->read_u16();
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m_context->header.bits_per_pixel = reader->read_u8();
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m_context->header.image_descriptor = reader->read_u8();
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auto bytes_remaining = reader->data().size() - reader->index();
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if (m_context->header.data_type_code == TGADataType::UncompressedRGB && bytes_remaining < static_cast<u64>(m_context->header.width) * m_context->header.height * (m_context->header.bits_per_pixel / 8))
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return Error::from_string_literal("Not enough data to read an image with the expected size");
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if (m_context->header.bits_per_pixel < 8 || m_context->header.bits_per_pixel > 32)
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return Error::from_string_literal("Invalid bit depth");
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m_context->header = TRY(m_context->stream.read_value<TGAHeader>());
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TRY(ensure_header_validity(m_context->header, m_context->stream.readonly_bytes().size()));
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return {};
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}
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ErrorOr<bool> TGAImageDecoderPlugin::validate_before_create(ReadonlyBytes data)
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{
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if (data.size() < sizeof(TGAHeader))
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return false;
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TGAHeader const& header = *reinterpret_cast<TGAHeader const*>(data.data());
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if (header.data_type_code == TGADataType::UncompressedRGB && data.size() < static_cast<u64>(header.width) * header.height * (header.bits_per_pixel / 8))
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return false;
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if (header.bits_per_pixel < 8 || header.bits_per_pixel > 32)
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return false;
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return true;
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FixedMemoryStream stream { data };
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auto header = TRY(stream.read_value<Gfx::TGAHeader>());
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return !ensure_header_validity(header, data.size()).is_error();
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}
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ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> TGAImageDecoderPlugin::create(ReadonlyBytes data)
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{
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auto plugin = TRY(adopt_nonnull_own_or_enomem(new (nothrow) TGAImageDecoderPlugin(data.data(), data.size())));
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FixedMemoryStream stream { data };
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auto context = TRY(adopt_nonnull_own_or_enomem(new (nothrow) TGALoadingContext(move(stream))));
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auto plugin = TRY(adopt_nonnull_own_or_enomem(new (nothrow) TGAImageDecoderPlugin(move(context))));
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TRY(plugin->decode_tga_header());
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return plugin;
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}
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static ErrorOr<ARGB32> read_pixel_from_stream(Stream& stream, size_t bytes_size)
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{
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// NOTE: We support 24-bit color pixels and 32-bit color pixels
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VERIFY(bytes_size == 3 || bytes_size == 4);
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if (bytes_size == 3) {
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Array<u8, 3> raw;
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TRY(stream.read_until_filled(raw.span()));
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return Color(raw[2], raw[1], raw[0]).value();
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}
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return stream.read_value<ARGB32>();
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}
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struct TGAPixelPacketHeader {
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bool raw { false };
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u8 pixels_count { 0 };
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};
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static ErrorOr<TGAPixelPacketHeader> read_pixel_packet_header(Stream& stream)
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{
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auto const pixel_packet_header = TRY(stream.read_value<u8>());
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bool pixels_raw_in_packet = !(pixel_packet_header & 0x80);
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u8 pixels_count_in_packet = (pixel_packet_header & 0x7f);
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// NOTE: Run-length-encoded/Raw pixel packets cannot encode zero pixels,
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// so value 0 stands for 1 pixel, 1 stands for 2, etc...
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pixels_count_in_packet++;
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VERIFY(pixels_count_in_packet > 0);
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return TGAPixelPacketHeader { pixels_raw_in_packet, pixels_count_in_packet };
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}
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ErrorOr<ImageFrameDescriptor> TGAImageDecoderPlugin::frame(size_t index, Optional<IntSize>)
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{
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auto bits_per_pixel = m_context->header.bits_per_pixel;
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@ -239,16 +150,8 @@ ErrorOr<ImageFrameDescriptor> TGAImageDecoderPlugin::frame(size_t index, Optiona
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if (color_map > 1)
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return Error::from_string_literal("TGAImageDecoderPlugin: Invalid color map type");
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if (m_context->bitmap) {
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if (m_context->bitmap)
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return ImageFrameDescriptor { m_context->bitmap, 0 };
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} else {
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// NOTE: Just to be on the safe side, if m_context->bitmap is nullptr, then
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// just re-construct the reader object. This will ensure that if the bitmap
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// was set as volatile and therefore it is gone, we can always re-generate it
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// with a new call to this method!
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VERIFY(m_context->reader);
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m_context->reader = make<TGAReader>(m_context->reader->data(), sizeof(TGAHeader));
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}
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RefPtr<Gfx::Bitmap> bitmap;
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switch (bits_per_pixel) {
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@ -278,30 +181,34 @@ ErrorOr<ImageFrameDescriptor> TGAImageDecoderPlugin::frame(size_t index, Optiona
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if (x_origin != 0 && x_origin != width)
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return Error::from_string_literal("TGAImageDecoderPlugin: Can only handle X origin which is 0 or the entire width");
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VERIFY((bits_per_pixel % 8) == 0);
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auto bytes_per_pixel = bits_per_pixel / 8;
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switch (data_type) {
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case TGADataType::UncompressedRGB: {
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for (int row = 0; row < height; ++row) {
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for (int col = 0; col < width; ++col) {
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auto pixel = m_context->reader->read_pixel(bits_per_pixel);
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auto actual_row = row;
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if (y_origin < height)
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actual_row = height - 1 - row;
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auto actual_col = col;
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if (x_origin > width)
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actual_col = width - 1 - col;
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bitmap->scanline(actual_row)[actual_col] = pixel.data;
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bitmap->scanline(actual_row)[actual_col] = TRY(read_pixel_from_stream(m_context->stream, bytes_per_pixel));
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}
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}
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break;
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}
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case TGADataType::RunLengthEncodedRGB: {
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size_t pixel_index = 0;
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size_t pixel_count = height * width;
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while (pixel_index < pixel_count) {
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auto packet_type = m_context->reader->read_packet_type();
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VERIFY(packet_type.pixels_count > 0);
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TGAPixel pixel = m_context->reader->read_pixel(bits_per_pixel);
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auto max_pixel_index = min(pixel_index + packet_type.pixels_count, pixel_count);
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auto pixel_packet_header = TRY(read_pixel_packet_header(m_context->stream));
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VERIFY(pixel_packet_header.pixels_count > 0);
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auto pixel = TRY(read_pixel_from_stream(m_context->stream, bytes_per_pixel));
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auto max_pixel_index = min(pixel_index + pixel_packet_header.pixels_count, pixel_count);
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for (size_t current_pixel_index = pixel_index; current_pixel_index < max_pixel_index; ++current_pixel_index) {
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int row = current_pixel_index / width;
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int col = current_pixel_index % width;
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@ -311,11 +218,11 @@ ErrorOr<ImageFrameDescriptor> TGAImageDecoderPlugin::frame(size_t index, Optiona
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auto actual_col = col;
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if (x_origin > width)
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actual_col = width - 1 - col;
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bitmap->scanline(actual_row)[actual_col] = pixel.data;
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if (packet_type.raw && (current_pixel_index + 1) < max_pixel_index)
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pixel = m_context->reader->read_pixel(bits_per_pixel);
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bitmap->scanline(actual_row)[actual_col] = pixel;
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if (pixel_packet_header.raw && (current_pixel_index + 1) < max_pixel_index)
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pixel = TRY(read_pixel_from_stream(m_context->stream, bytes_per_pixel));
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}
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pixel_index += packet_type.pixels_count;
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pixel_index += pixel_packet_header.pixels_count;
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}
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break;
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}
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