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LibGfx/JBIG2: Decode all segment headers

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With `#define JBIG2_DEBUG 1` at the top of the file:

    % Build/lagom/bin/image --no-output \
       .../JBIG2_ConformanceData-A20180829/F01_200_TT10.jb2
    JBIG2LoadingContext: Organization: 0 (Sequential)
    JBIG2LoadingContext: Number of pages: 1
    Segment number: 0
    Segment type: 48
    Referred to segment count: 0
    Segment page association: 1
    Segment data length: 19
    Segment number: 1
    Segment type: 39
    Referred to segment count: 0
    Segment page association: 1
    Segment data length: 12666
    Segment number: 2
    Segment type: 49
    Referred to segment count: 0
    Segment page association: 1
    Segment data length: 0
    Runtime error: JBIG2ImageDecoderPlugin: Draw the rest of the owl
This commit is contained in:
Nico Weber 2024-03-03 20:51:38 -05:00 • committed by Andreas Kling
parent 177664cfae
commit b1fdc33a22
1 changed files with 20 additions and 5 deletions
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25
Userland/Libraries/LibGfx/ImageFormats/JBIG2Loader.cpp
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@ -106,11 +106,8 @@ static ErrorOr<void> decode_jbig2_header(JBIG2LoadingContext& context)
return {};
}
static ErrorOr<SegmentHeader> decode_segment_header(JBIG2LoadingContext& context)
static ErrorOr<SegmentHeader> decode_segment_header(SeekableStream& stream)
{
ReadonlyBytes data = context.data.slice(sizeof(id_string) + sizeof(u8) + (context.number_of_pages.has_value() ? sizeof(u32) : 0));
FixedMemoryStream stream(data);
// 7.2.2 Segment number
u32 segment_number = TRY(stream.read_value<BigEndian<u32>>());
dbgln_if(JBIG2_DEBUG, "Segment number: {}", segment_number);
@ -181,6 +178,24 @@ static ErrorOr<SegmentHeader> decode_segment_header(JBIG2LoadingContext& context
return SegmentHeader { segment_number, type, move(referred_to_segment_numbers), segment_page_association, opt_data_length };
}
static ErrorOr<void> decode_segment_headers(JBIG2LoadingContext& context)
{
FixedMemoryStream stream(context.data.slice(sizeof(id_string) + sizeof(u8) + (context.number_of_pages.has_value() ? sizeof(u32) : 0)));
while (!stream.is_eof()) {
auto segment_header = TRY(decode_segment_header(stream));
if (context.organization != Organization::RandomAccess) {
if (!segment_header.data_length.has_value())
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Can't handle non-random-access organization segment without data length yet");
TRY(stream.seek(segment_header.data_length.value(), SeekMode::FromCurrentPosition));
}
// Required per spec for files with RandomAccess organization.
if (segment_header.type == SegmentType::EndOfFile)
break;
}
return {};
}
JBIG2ImageDecoderPlugin::JBIG2ImageDecoderPlugin(ReadonlyBytes data)
{
m_context = make<JBIG2LoadingContext>();
@ -201,7 +216,7 @@ ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> JBIG2ImageDecoderPlugin::create(Reado
{
auto plugin = TRY(adopt_nonnull_own_or_enomem(new (nothrow) JBIG2ImageDecoderPlugin(data)));
TRY(decode_jbig2_header(*plugin->m_context));
TRY(decode_segment_header(*plugin->m_context));
TRY(decode_segment_headers(*plugin->m_context));
return plugin;
}