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LibGfx/JPEG: Split spectral_approximation

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This `u8` is actually two values of 4 bits. Let's store them separately
to avoid confusion.
This commit is contained in:
Lucas CHOLLET 2023-02-26 01:53:24 -05:00 • committed by Linus Groh
parent 5c76b63f79
commit ef98b06dff
1 changed files with 14 additions and 9 deletions
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23
Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp
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@ -199,9 +199,10 @@ struct Scan {
// B.2.3 - Scan header syntax
Vector<ScanComponent, 3> components;
u8 spectral_selection_start {};
u8 spectral_selection_end {};
u8 successive_approximation {};
u8 spectral_selection_start {}; // Ss
u8 spectral_selection_end {}; // Se
u8 successive_approximation_high {}; // Ah
u8 successive_approximation_low {}; // Al
HuffmanStreamState huffman_stream;
@ -662,19 +663,23 @@ static ErrorOr<void> read_start_of_scan(Stream& stream, JPEGLoadingContext& cont
current_scan.spectral_selection_start = TRY(stream.read_value<u8>());
current_scan.spectral_selection_end = TRY(stream.read_value<u8>());
current_scan.successive_approximation = TRY(stream.read_value<u8>());
auto const successive_approximation = TRY(stream.read_value<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: {}",
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);
current_scan.successive_approximation_high,
current_scan.successive_approximation_low);
// FIXME: Support SOF2 jpegs with current_scan.successive_approximation != 0
if (current_scan.spectral_selection_start > 63 || current_scan.spectral_selection_end > 63 || current_scan.successive_approximation != 0) {
dbgln_if(JPEG_DEBUG, "ERROR! Start of Selection: {}, End of Selection: {}, Successive Approximation: {}!",
if (current_scan.spectral_selection_start > 63 || current_scan.spectral_selection_end > 63 || successive_approximation != 0) {
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);
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");
}