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special version of sample formatting for common cases

This commit is contained in:
Josh Coalson 2007-03-22 03:15:07 +00:00
parent feeca21bde
commit db55c40fd3
1 changed files with 60 additions and 18 deletions
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64
src/flac/decode.c
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@ -904,30 +904,59 @@ FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder *decoder
&decoder_session->replaygain.dither_context
);
}
else if(bps+shift == 8) {
if(is_unsigned_samples) {
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++)
for(channel = 0; channel < channels; channel++, sample++)
u8buffer[sample] = (FLAC__uint8)(buffer[channel][wide_sample] + 0x80);
/* first some special code for common cases */
else if(is_big_endian == is_big_endian_host_ && !is_unsigned_samples && channels == 2 && bps+shift == 16) {
FLAC__int16 *buf1_ = s16buffer + 1;
if(is_big_endian)
memcpy(s16buffer, ((FLAC__byte*)(buffer[0]))+2, sizeof(FLAC__int32) * wide_samples - 2);
else
memcpy(s16buffer, buffer[0], sizeof(FLAC__int32) * wide_samples);
for(sample = 0; sample < wide_samples; sample++, buf1_+=2)
*buf1_ = (FLAC__int16)buffer[1][sample];
bytes_to_write = 4 * sample;
}
else {
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++)
for(channel = 0; channel < channels; channel++, sample++)
s8buffer[sample] = (FLAC__int8)(buffer[channel][wide_sample]);
}
bytes_to_write = sample;
else if(is_big_endian == is_big_endian_host_ && !is_unsigned_samples && channels == 1 && bps+shift == 16) {
FLAC__int16 *buf1_ = s16buffer;
for(sample = 0; sample < wide_samples; sample++)
*buf1_++ = (FLAC__int16)buffer[0][sample];
bytes_to_write = 2 * sample;
}
/* generic code for the rest */
else if(bps+shift == 16) {
if(is_unsigned_samples) {
if(channels == 2) {
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++) {
u16buffer[sample++] = (FLAC__uint16)(buffer[0][wide_sample] + 0x8000);
u16buffer[sample++] = (FLAC__uint16)(buffer[1][wide_sample] + 0x8000);
}
}
else if(channels == 1) {
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++)
u16buffer[sample++] = (FLAC__uint16)(buffer[0][wide_sample] + 0x8000);
}
else { /* works for any 'channels' but above flavors are faster for 1 and 2 */
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++)
for(channel = 0; channel < channels; channel++, sample++)
u16buffer[sample] = (FLAC__uint16)(buffer[channel][wide_sample] + 0x8000);
}
}
else {
if(channels == 2) {
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++) {
s16buffer[sample++] = (FLAC__int16)(buffer[0][wide_sample]);
s16buffer[sample++] = (FLAC__int16)(buffer[1][wide_sample]);
}
}
else if(channels == 1) {
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++)
s16buffer[sample++] = (FLAC__int16)(buffer[0][wide_sample]);
}
else { /* works for any 'channels' but above flavors are faster for 1 and 2 */
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++)
for(channel = 0; channel < channels; channel++, sample++)
s16buffer[sample] = (FLAC__int16)(buffer[channel][wide_sample]);
}
}
if(is_big_endian != is_big_endian_host_) {
unsigned char tmp;
const unsigned bytes = sample * 2;
@ -984,6 +1013,19 @@ FLAC__StreamDecoderWriteStatus write_callback(const FLAC__StreamDecoder *decoder
}
bytes_to_write = 3 * sample;
}
else if(bps+shift == 8) {
if(is_unsigned_samples) {
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++)
for(channel = 0; channel < channels; channel++, sample++)
u8buffer[sample] = (FLAC__uint8)(buffer[channel][wide_sample] + 0x80);
}
else {
for(sample = wide_sample = 0; wide_sample < wide_samples; wide_sample++)
for(channel = 0; channel < channels; channel++, sample++)
s8buffer[sample] = (FLAC__int8)(buffer[channel][wide_sample]);
}
bytes_to_write = sample;
}
else {
FLAC__ASSERT(0);
/* double protection */