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LibGfx/JPEGXL: Make EntropyDecoder::read_config() static

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This function will soon be used for the LZ77 decoder with a different
parameter than `m_log_alphabet_size`.
This commit is contained in:
Lucas CHOLLET 2023-07-23 14:32:13 -04:00 committed by Jelle Raaijmakers
parent a0bceeb704
commit 07ea66528e
Notes: sideshowbarker 2024-07-17 06:54:15 +09:00 
Author: https://github.com/LucasChollet
Commit: https://github.com/SerenityOS/serenity/commit/07ea66528e
Pull-request: https://github.com/SerenityOS/serenity/pull/20480
Reviewed-by: https://github.com/gmta ✅
1 changed files with 20 additions and 20 deletions
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40
Userland/Libraries/LibGfx/ImageFormats/JPEGXLLoader.cpp
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@ -1158,7 +1158,7 @@ public:
entropy_decoder.m_log_alphabet_size = 5 + TRY(stream.read_bits(2));
for (auto& config : entropy_decoder.m_configs)
config = TRY(entropy_decoder.read_config(stream));
config = TRY(read_config(stream, entropy_decoder.m_log_alphabet_size));
if (use_prefix_code) {
entropy_decoder.m_distributions = Vector<BrotliCanonicalCode> {};
@ -1257,6 +1257,25 @@ private:
return result;
}
static ErrorOr<HybridUint> read_config(LittleEndianInputBitStream& stream, u8 log_alphabet_size)
{
// C.2.3 - Hybrid integer configuration
HybridUint config {};
config.split_exponent = TRY(stream.read_bits(ceil(log2(log_alphabet_size + 1))));
if (config.split_exponent != log_alphabet_size) {
auto nbits = ceil(log2(config.split_exponent + 1));
config.msb_in_token = TRY(stream.read_bits(nbits));
nbits = ceil(log2(config.split_exponent - config.msb_in_token + 1));
config.lsb_in_token = TRY(stream.read_bits(nbits));
} else {
config.msb_in_token = 0;
config.lsb_in_token = 0;
}
config.split = 1 << config.split_exponent;
return config;
}
ErrorOr<void> read_pre_clustered_distributions(LittleEndianInputBitStream& stream, u8 num_distrib)
{
// C.2.2 Distribution clustering
@ -1301,25 +1320,6 @@ private:
return {};
}
ErrorOr<HybridUint> read_config(LittleEndianInputBitStream& stream) const
{
// C.2.3 - Hybrid integer configuration
HybridUint config {};
config.split_exponent = TRY(stream.read_bits(ceil(log2(m_log_alphabet_size + 1))));
if (config.split_exponent != m_log_alphabet_size) {
auto nbits = ceil(log2(config.split_exponent + 1));
config.msb_in_token = TRY(stream.read_bits(nbits));
nbits = ceil(log2(config.split_exponent - config.msb_in_token + 1));
config.lsb_in_token = TRY(stream.read_bits(nbits));
} else {
config.msb_in_token = 0;
config.lsb_in_token = 0;
}
config.split = 1 << config.split_exponent;
return config;
}
bool m_lz77_enabled {};
Vector<u32> m_clusters;
Vector<HybridUint> m_configs;