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minor optimizations to FLAC__bitreader_read_rice_signed_block()

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This commit is contained in:
Josh Coalson 2007-03-22 03:20:12 +00:00
parent f1dfaebdfa
commit 276d616a51
1 changed files with 10 additions and 14 deletions
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24
src/libFLAC/bitreader.c
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@ -733,7 +733,7 @@ FLaC__INLINE FLAC__bool FLAC__bitreader_read_unary_unsigned(FLAC__BitReader *br,
*val += i;
i++;
br->consumed_bits += i;
if(br->consumed_bits == FLAC__BITS_PER_WORD) {
if(br->consumed_bits >= FLAC__BITS_PER_WORD) { /* faster way of testing if(br->consumed_bits == FLAC__BITS_PER_WORD) */
crc16_update_word_(br, br->buffer[br->consumed_words]);
br->consumed_words++;
br->consumed_bits = 0;
@ -855,7 +855,7 @@ FLAC__bool FLAC__bitreader_read_rice_signed_block(FLAC__BitReader *br, int vals[
uval += i;
cbits += i;
cbits++; /* skip over stop bit */
if(cbits == FLAC__BITS_PER_WORD) {
if(cbits >= FLAC__BITS_PER_WORD) { /* faster way of testing if(cbits == FLAC__BITS_PER_WORD) */
crc16_update_word_(br, br->buffer[cwords]);
cwords++;
cbits = 0;
@ -940,7 +940,6 @@ break1:
/* this also works when consumed_bits==0, it's just a little slower than necessary for that case */
const unsigned n = FLAC__BITS_PER_WORD - cbits;
const brword word = br->buffer[cwords];
unsigned bits;
if(parameter < n) {
uval <<= parameter;
uval |= (word & (FLAC__WORD_ALL_ONES >> cbits)) >> (n-parameter);
@ -949,22 +948,19 @@ break1:
}
uval <<= n;
uval |= word & (FLAC__WORD_ALL_ONES >> cbits);
bits = parameter - n;
crc16_update_word_(br, word);
cwords++;
cbits = 0;
if(bits) { /* if there are still bits left to read, there have to be less than 32 so they will all be in the next word */
uval <<= bits;
uval |= (br->buffer[cwords] >> (FLAC__BITS_PER_WORD-bits));
cbits = bits;
cbits = parameter - n;
if(cbits) { /* parameter > n, i.e. if there are still bits left to read, there have to be less than 32 so they will all be in the next word */
uval <<= cbits;
uval |= (br->buffer[cwords] >> (FLAC__BITS_PER_WORD-cbits));
}
goto break2;
}
else {
FLAC__ASSERT(parameter < FLAC__BITS_PER_WORD);
uval <<= parameter;
uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-parameter);
cbits = parameter;
uval <<= parameter;
uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-cbits);
goto break2;
}
}
@ -982,8 +978,8 @@ break1:
goto break2;
}
else {
uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-parameter);
cbits += parameter;
cbits = parameter;
uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-cbits);
goto break2;
}
}