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LibAudio: Remove unnecessary m_bitstream field from MP3Loader

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We can just create a `BigEndianInputBitStream` where it is needed
instead of storing one in the class. After making `read_header()`
static, the only other user of the field was `read_size_information()`,
so let's do that there and then remove the field.
This commit is contained in:
Zaggy1024 2023-08-26 02:12:03 -05:00 committed by Tim Flynn
parent c1d4ff919a
commit b33a71a35e
2 changed files with 23 additions and 28 deletions
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50
Userland/Libraries/LibAudio/MP3Loader.cpp
View file

@ -65,7 +65,6 @@ MaybeLoaderError MP3LoaderPlugin::initialize()
{
TRY(build_seek_table());
m_bitstream = TRY(try_make<BigEndianInputBitStream>(MaybeOwned<Stream>(*m_stream)));
TRY(seek(0));
auto header = TRY(synchronize_and_read_header());
@ -84,7 +83,6 @@ MaybeLoaderError MP3LoaderPlugin::reset()
m_synthesis_buffer = {};
m_loaded_samples = 0;
TRY(m_bit_reservoir.discard(m_bit_reservoir.used_buffer_size()));
m_bitstream->align_to_byte_boundary();
return {};
}
@ -97,7 +95,6 @@ MaybeLoaderError MP3LoaderPlugin::seek(int const position)
}
m_synthesis_buffer = {};
TRY(m_bit_reservoir.discard(m_bit_reservoir.used_buffer_size()));
m_bitstream->align_to_byte_boundary();
return {};
}
@ -229,10 +226,7 @@ ErrorOr<MP3::Header, LoaderError> MP3LoaderPlugin::synchronize_and_read_header(S
ErrorOr<MP3::Header, LoaderError> MP3LoaderPlugin::synchronize_and_read_header()
{
auto header = TRY(MP3LoaderPlugin::synchronize_and_read_header(*m_stream, m_loaded_samples));
if (m_bitstream)
m_bitstream->align_to_byte_boundary();
return header;
return MP3LoaderPlugin::synchronize_and_read_header(*m_stream, m_loaded_samples);
}
ErrorOr<MP3::MP3Frame, LoaderError> MP3LoaderPlugin::read_next_frame()
@ -252,7 +246,7 @@ ErrorOr<MP3::MP3Frame, LoaderError> MP3LoaderPlugin::read_frame_data(MP3::Header
auto& buffer = maybe_buffer.value();
size_t old_reservoir_size = m_bit_reservoir.used_buffer_size();
TRY(m_bitstream->read_until_filled(buffer));
TRY(m_stream->read_until_filled(buffer));
TRY(m_bit_reservoir.write_until_depleted(buffer));
// If we don't have enough data in the reservoir to process this frame, skip it (but keep the data).
@ -331,46 +325,48 @@ ErrorOr<MP3::MP3Frame, LoaderError> MP3LoaderPlugin::read_frame_data(MP3::Header
MaybeLoaderError MP3LoaderPlugin::read_side_information(MP3::MP3Frame& frame)
{
frame.main_data_begin = TRY(m_bitstream->read_bits(9));
auto bitstream = BigEndianInputBitStream(MaybeOwned<Stream>(*m_stream));
frame.main_data_begin = TRY(bitstream.read_bits(9));
if (frame.header.channel_count() == 1) {
frame.private_bits = TRY(m_bitstream->read_bits(5));
frame.private_bits = TRY(bitstream.read_bits(5));
} else {
frame.private_bits = TRY(m_bitstream->read_bits(3));
frame.private_bits = TRY(bitstream.read_bits(3));
}
for (size_t channel_index = 0; channel_index < frame.header.channel_count(); channel_index++) {
for (size_t scale_factor_selection_info_band = 0; scale_factor_selection_info_band < 4; scale_factor_selection_info_band++) {
frame.channels[channel_index].scale_factor_selection_info[scale_factor_selection_info_band] = TRY(m_bitstream->read_bit());
frame.channels[channel_index].scale_factor_selection_info[scale_factor_selection_info_band] = TRY(bitstream.read_bit());
}
}
for (size_t granule_index = 0; granule_index < 2; granule_index++) {
for (size_t channel_index = 0; channel_index < frame.header.channel_count(); channel_index++) {
auto& granule = frame.channels[channel_index].granules[granule_index];
granule.part_2_3_length = TRY(m_bitstream->read_bits(12));
granule.big_values = TRY(m_bitstream->read_bits(9));
granule.global_gain = TRY(m_bitstream->read_bits(8));
granule.scalefac_compress = TRY(m_bitstream->read_bits(4));
granule.window_switching_flag = TRY(m_bitstream->read_bit());
granule.part_2_3_length = TRY(bitstream.read_bits(12));
granule.big_values = TRY(bitstream.read_bits(9));
granule.global_gain = TRY(bitstream.read_bits(8));
granule.scalefac_compress = TRY(bitstream.read_bits(4));
granule.window_switching_flag = TRY(bitstream.read_bit());
if (granule.window_switching_flag) {
granule.block_type = static_cast<MP3::BlockType>(TRY(m_bitstream->read_bits(2)));
granule.mixed_block_flag = TRY(m_bitstream->read_bit());
granule.block_type = static_cast<MP3::BlockType>(TRY(bitstream.read_bits(2)));
granule.mixed_block_flag = TRY(bitstream.read_bit());
for (size_t region = 0; region < 2; region++)
granule.table_select[region] = TRY(m_bitstream->read_bits(5));
granule.table_select[region] = TRY(bitstream.read_bits(5));
for (size_t window = 0; window < 3; window++)
granule.sub_block_gain[window] = TRY(m_bitstream->read_bits(3));
granule.sub_block_gain[window] = TRY(bitstream.read_bits(3));
granule.region0_count = (granule.block_type == MP3::BlockType::Short && !granule.mixed_block_flag) ? 8 : 7;
granule.region1_count = 36;
} else {
for (size_t region = 0; region < 3; region++)
granule.table_select[region] = TRY(m_bitstream->read_bits(5));
granule.region0_count = TRY(m_bitstream->read_bits(4));
granule.region1_count = TRY(m_bitstream->read_bits(3));
granule.table_select[region] = TRY(bitstream.read_bits(5));
granule.region0_count = TRY(bitstream.read_bits(4));
granule.region1_count = TRY(bitstream.read_bits(3));
}
granule.preflag = TRY(m_bitstream->read_bit());
granule.scalefac_scale = TRY(m_bitstream->read_bit());
granule.count1table_select = TRY(m_bitstream->read_bit());
granule.preflag = TRY(bitstream.read_bit());
granule.scalefac_scale = TRY(bitstream.read_bit());
granule.count1table_select = TRY(bitstream.read_bit());
}
}
return {};

1
Userland/Libraries/LibAudio/MP3Loader.h
View file

@ -72,7 +72,6 @@ private:
int m_total_samples { 0 };
size_t m_loaded_samples { 0 };
OwnPtr<BigEndianInputBitStream> m_bitstream;
AllocatingMemoryStream m_bit_reservoir;
};