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LibGfx/JBIG2: Extract check_valid_adaptive_template_pixel()

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No behavior change.
This commit is contained in:
Nico Weber 2024-04-04 13:13:35 -07:00 committed by Andreas Kling
parent 200e36aad3
commit 154d0bb458
1 changed files with 14 additions and 13 deletions
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27
Userland/Libraries/LibGfx/ImageFormats/JBIG2Loader.cpp
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@ -900,6 +900,17 @@ struct AdaptiveTemplatePixel {
i8 y { 0 };
};
// Figure 7 – Field to which AT pixel locations are restricted
static ErrorOr<void> check_valid_adaptive_template_pixel(AdaptiveTemplatePixel const& adaptive_template_pixel)
{
// Don't have to check < -127 or > 127: The offsets are stored in an i8, so they can't be out of those bounds.
if (adaptive_template_pixel.y > 0)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Adaptive pixel y too big");
if (adaptive_template_pixel.y == 0 && adaptive_template_pixel.x > -1)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Adaptive pixel x too big");
return {};
}
// 6.2.2 Input parameters
// Table 2 – Parameters for the generic region decoding procedure
struct GenericRegionDecodingInputParameters {
@ -945,19 +956,9 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_region_decoding_procedure(Gener
if (inputs.is_extended_reference_template_used)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode EXTTEMPLATE yet");
// Figure 7 – Field to which AT pixel locations are restricted
int number_of_adaptive_template_pixels = 0;
if (inputs.gb_template == 0)
number_of_adaptive_template_pixels = 4;
else
number_of_adaptive_template_pixels = 1;
for (int i = 0; i < number_of_adaptive_template_pixels; ++i) {
// Don't have to check < -127 or > 127: The offsets are stored in an i8, so they can't be out of those bounds.
if (inputs.adaptive_template_pixels[i].y > 0)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Adaptive pixel y too big");
if (inputs.adaptive_template_pixels[i].y == 0 && inputs.adaptive_template_pixels[i].x > -1)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Adaptive pixel x too big");
}
int number_of_adaptive_template_pixels = inputs.gb_template == 0 ? 4 : 1;
for (int i = 0; i < number_of_adaptive_template_pixels; ++i)
TRY(check_valid_adaptive_template_pixel(inputs.adaptive_template_pixels[i]));
if (inputs.skip_pattern.has_value())
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode USESKIP yet");