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LibGfx/GIF: Only use a FixedMemoryStream

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This allows us to drop the data pointer in the `GIFLoadingContext`.
This commit is contained in:
Lucas CHOLLET 2023-07-14 17:45:19 -04:00 • committed by Andreas Kling
parent 1192e46c09
commit b8bc84a3e8
2 changed files with 39 additions and 35 deletions
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71
Userland/Libraries/LibGfx/ImageFormats/GIFLoader.cpp
View file

@ -59,6 +59,11 @@ struct LogicalScreen {
}; };
struct GIFLoadingContext { struct GIFLoadingContext {
GIFLoadingContext(FixedMemoryStream stream)
: stream(move(stream))
{
}
enum State { enum State {
NotDecoded = 0, NotDecoded = 0,
FrameDescriptorsLoaded, FrameDescriptorsLoaded,
@ -72,8 +77,9 @@ struct GIFLoadingContext {
FailedToLoadFrameDescriptors, FailedToLoadFrameDescriptors,
}; };
ErrorState error_state { NoError }; ErrorState error_state { NoError };
u8 const* data { nullptr };
size_t data_size { 0 }; FixedMemoryStream stream;
LogicalScreen logical_screen {}; LogicalScreen logical_screen {};
u8 background_color_index { 0 }; u8 background_color_index { 0 };
Vector<NonnullOwnPtr<GIFImageDescriptor>> images {}; Vector<NonnullOwnPtr<GIFImageDescriptor>> images {};
@ -377,24 +383,22 @@ static ErrorOr<void> decode_frame(GIFLoadingContext& context, size_t frame_index
static ErrorOr<void> load_gif_frame_descriptors(GIFLoadingContext& context) static ErrorOr<void> load_gif_frame_descriptors(GIFLoadingContext& context)
{ {
if (context.data_size < 32) if (TRY(context.stream.size()) < 32)
return Error::from_string_literal("Size too short for GIF frame descriptors"); return Error::from_string_literal("Size too short for GIF frame descriptors");
FixedMemoryStream stream { { context.data, context.data_size } }; TRY(decode_gif_header(context.stream));
TRY(decode_gif_header(stream)); context.logical_screen.width = TRY(context.stream.read_value<LittleEndian<u16>>());
context.logical_screen.height = TRY(context.stream.read_value<LittleEndian<u16>>());
context.logical_screen.width = TRY(stream.read_value<LittleEndian<u16>>());
context.logical_screen.height = TRY(stream.read_value<LittleEndian<u16>>());
if (context.logical_screen.width > maximum_width_for_decoded_images || context.logical_screen.height > maximum_height_for_decoded_images) { if (context.logical_screen.width > maximum_width_for_decoded_images || context.logical_screen.height > maximum_height_for_decoded_images) {
dbgln("This GIF is too large for comfort: {}x{}", context.logical_screen.width, context.logical_screen.height); dbgln("This GIF is too large for comfort: {}x{}", context.logical_screen.width, context.logical_screen.height);
return Error::from_string_literal("This GIF is too large for comfort"); return Error::from_string_literal("This GIF is too large for comfort");
} }
auto gcm_info = TRY(stream.read_value<u8>()); auto gcm_info = TRY(context.stream.read_value<u8>());
context.background_color_index = TRY(stream.read_value<u8>()); context.background_color_index = TRY(context.stream.read_value<u8>());
[[maybe_unused]] auto pixel_aspect_ratio = TRY(stream.read_value<u8>()); [[maybe_unused]] auto pixel_aspect_ratio = TRY(context.stream.read_value<u8>());
u8 bits_per_pixel = (gcm_info & 7) + 1; u8 bits_per_pixel = (gcm_info & 7) + 1;
int color_map_entry_count = 1; int color_map_entry_count = 1;
@ -402,29 +406,29 @@ static ErrorOr<void> load_gif_frame_descriptors(GIFLoadingContext& context)
color_map_entry_count *= 2; color_map_entry_count *= 2;
for (int i = 0; i < color_map_entry_count; ++i) { for (int i = 0; i < color_map_entry_count; ++i) {
u8 r = TRY(stream.read_value<u8>()); u8 r = TRY(context.stream.read_value<u8>());
u8 g = TRY(stream.read_value<u8>()); u8 g = TRY(context.stream.read_value<u8>());
u8 b = TRY(stream.read_value<u8>()); u8 b = TRY(context.stream.read_value<u8>());
context.logical_screen.color_map[i] = { r, g, b }; context.logical_screen.color_map[i] = { r, g, b };
} }
NonnullOwnPtr<GIFImageDescriptor> current_image = make<GIFImageDescriptor>(); NonnullOwnPtr<GIFImageDescriptor> current_image = make<GIFImageDescriptor>();
for (;;) { for (;;) {
u8 sentinel = TRY(stream.read_value<u8>()); u8 sentinel = TRY(context.stream.read_value<u8>());
if (sentinel == '!') { if (sentinel == '!') {
u8 extension_type = TRY(stream.read_value<u8>()); u8 extension_type = TRY(context.stream.read_value<u8>());
u8 sub_block_length = 0; u8 sub_block_length = 0;
Vector<u8> sub_block {}; Vector<u8> sub_block {};
for (;;) { for (;;) {
sub_block_length = TRY(stream.read_value<u8>()); sub_block_length = TRY(context.stream.read_value<u8>());
if (sub_block_length == 0) if (sub_block_length == 0)
break; break;
TRY(sub_block.try_resize(sub_block.size() + sub_block_length)); TRY(sub_block.try_resize(sub_block.size() + sub_block_length));
TRY(stream.read_until_filled(sub_block.span().slice_from_end(sub_block_length))); TRY(context.stream.read_until_filled(sub_block.span().slice_from_end(sub_block_length)));
} }
if (extension_type == 0xF9) { if (extension_type == 0xF9) {
@ -470,12 +474,12 @@ static ErrorOr<void> load_gif_frame_descriptors(GIFLoadingContext& context)
context.images.append(move(current_image)); context.images.append(move(current_image));
auto& image = context.images.last(); auto& image = context.images.last();
image->x = TRY(stream.read_value<LittleEndian<u16>>()); image->x = TRY(context.stream.read_value<LittleEndian<u16>>());
image->y = TRY(stream.read_value<LittleEndian<u16>>()); image->y = TRY(context.stream.read_value<LittleEndian<u16>>());
image->width = TRY(stream.read_value<LittleEndian<u16>>()); image->width = TRY(context.stream.read_value<LittleEndian<u16>>());
image->height = TRY(stream.read_value<LittleEndian<u16>>()); image->height = TRY(context.stream.read_value<LittleEndian<u16>>());
auto packed_fields = TRY(stream.read_value<u8>()); auto packed_fields = TRY(context.stream.read_value<u8>());
image->use_global_color_map = !(packed_fields & 0x80); image->use_global_color_map = !(packed_fields & 0x80);
image->interlaced = (packed_fields & 0x40) != 0; image->interlaced = (packed_fields & 0x40) != 0;
@ -484,24 +488,24 @@ static ErrorOr<void> load_gif_frame_descriptors(GIFLoadingContext& context)
size_t local_color_table_size = AK::exp2<size_t>((packed_fields & 7) + 1); size_t local_color_table_size = AK::exp2<size_t>((packed_fields & 7) + 1);
for (size_t i = 0; i < local_color_table_size; ++i) { for (size_t i = 0; i < local_color_table_size; ++i) {
u8 r = TRY(stream.read_value<u8>()); u8 r = TRY(context.stream.read_value<u8>());
u8 g = TRY(stream.read_value<u8>()); u8 g = TRY(context.stream.read_value<u8>());
u8 b = TRY(stream.read_value<u8>()); u8 b = TRY(context.stream.read_value<u8>());
image->color_map[i] = { r, g, b }; image->color_map[i] = { r, g, b };
} }
} }
image->lzw_min_code_size = TRY(stream.read_value<u8>()); image->lzw_min_code_size = TRY(context.stream.read_value<u8>());
u8 lzw_encoded_bytes_expected = 0; u8 lzw_encoded_bytes_expected = 0;
for (;;) { for (;;) {
lzw_encoded_bytes_expected = TRY(stream.read_value<u8>()); lzw_encoded_bytes_expected = TRY(context.stream.read_value<u8>());
if (lzw_encoded_bytes_expected == 0) if (lzw_encoded_bytes_expected == 0)
break; break;
Array<u8, 256> buffer; Array<u8, 256> buffer;
TRY(stream.read_until_filled(buffer.span().trim(lzw_encoded_bytes_expected))); TRY(context.stream.read_until_filled(buffer.span().trim(lzw_encoded_bytes_expected)));
for (int i = 0; i < lzw_encoded_bytes_expected; ++i) { for (int i = 0; i < lzw_encoded_bytes_expected; ++i) {
image->lzw_encoded_bytes.append(buffer[i]); image->lzw_encoded_bytes.append(buffer[i]);
@ -523,11 +527,9 @@ static ErrorOr<void> load_gif_frame_descriptors(GIFLoadingContext& context)
return {}; return {};
} }
GIFImageDecoderPlugin::GIFImageDecoderPlugin(u8 const* data, size_t size) GIFImageDecoderPlugin::GIFImageDecoderPlugin(FixedMemoryStream stream)
{ {
m_context = make<GIFLoadingContext>(); m_context = make<GIFLoadingContext>(move(stream));
m_context->data = data;
m_context->data_size = size;
} }
GIFImageDecoderPlugin::~GIFImageDecoderPlugin() = default; GIFImageDecoderPlugin::~GIFImageDecoderPlugin() = default;
@ -556,7 +558,8 @@ bool GIFImageDecoderPlugin::sniff(ReadonlyBytes data)
ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> GIFImageDecoderPlugin::create(ReadonlyBytes data) ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> GIFImageDecoderPlugin::create(ReadonlyBytes data)
{ {
return adopt_nonnull_own_or_enomem(new (nothrow) GIFImageDecoderPlugin(data.data(), data.size())); FixedMemoryStream stream { data };
return adopt_nonnull_own_or_enomem(new (nothrow) GIFImageDecoderPlugin(move(stream)));
} }
bool GIFImageDecoderPlugin::is_animated() bool GIFImageDecoderPlugin::is_animated()

3
Userland/Libraries/LibGfx/ImageFormats/GIFLoader.h
View file

@ -6,6 +6,7 @@
#pragma once #pragma once
#include <AK/MemoryStream.h>
#include <LibGfx/Bitmap.h> #include <LibGfx/Bitmap.h>
#include <LibGfx/ImageFormats/ImageDecoder.h> #include <LibGfx/ImageFormats/ImageDecoder.h>
@ -30,7 +31,7 @@ public:
virtual ErrorOr<Optional<ReadonlyBytes>> icc_data() override; virtual ErrorOr<Optional<ReadonlyBytes>> icc_data() override;
private: private:
GIFImageDecoderPlugin(u8 const*, size_t); GIFImageDecoderPlugin(FixedMemoryStream);
OwnPtr<GIFLoadingContext> m_context; OwnPtr<GIFLoadingContext> m_context;
}; };