minor optimizations to FLAC__bitbuffer_read_rice_signed_block()
diff --git a/src/libFLAC/bitreader.c b/src/libFLAC/bitreader.c
index 4f3874f..be09574 100644
--- a/src/libFLAC/bitreader.c
+++ b/src/libFLAC/bitreader.c
@@ -131,6 +131,7 @@
#define FLaC__INLINE
#endif
+/* WATCHOUT: assembly routines rely on the order in which these fields are declared */
struct FLAC__BitReader {
/* any partially-consumed word at the head will stay right-justified as bits are consumed from the left */
/* any incomplete word at the tail will be left-justified, and bytes from the read callback are added on the right */
@@ -138,7 +139,8 @@
unsigned capacity; /* in words */
unsigned words; /* # of completed words in buffer */
unsigned bytes; /* # of bytes in incomplete word at buffer[words] */
- unsigned consumed_words, consumed_bits; /* #words+(#bits of head word) already consumed from the front of buffer */
+ unsigned consumed_words; /* #words ... */
+ unsigned consumed_bits; /* ... + (#bits of head word) already consumed from the front of buffer */
unsigned read_crc16; /* the running frame CRC */
unsigned crc16_align; /* the number of bits in the current consumed word that should not be CRC'd */
FLAC__BitReaderReadCallback read_callback;
@@ -201,7 +203,8 @@
br->crc16_align = 0;
}
-static FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br)
+/* would be static except it needs to be called by asm routines */
+FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br)
{
unsigned start, end;
size_t bytes;
@@ -827,7 +830,7 @@
/* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */
FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32);
FLAC__ASSERT(parameter < 32);
- /* the above two asserts also guarantee that the binary part never straddles more that 2 words, so we don't have to loop to read it */
+ /* the above two asserts also guarantee that the binary part never straddles more than 2 words, so we don't have to loop to read it */
if(nvals == 0)
return true;
@@ -849,9 +852,9 @@
i = ALIGNED_UNARY_BITS(b);
#endif
uval += i;
- bits = parameter;
- i++;
cbits += i;
+ bits = parameter;
+ cbits++; /* skip over stop bit */
if(cbits == FLAC__BITS_PER_WORD) {
crc16_update_word_(br, br->buffer[cwords]);
cwords++;
@@ -876,7 +879,7 @@
*/
if(br->bytes) {
const unsigned end = br->bytes * 8;
- brword b = (br->buffer[cwords] & (FLAC__WORD_ALL_ONES << (FLAC__BITS_PER_WORD-end))) << cbits;
+ brword b = (br->buffer[cwords] & ~(FLAC__WORD_ALL_ONES >> end)) << cbits;
if(b) {
#if 0 /* too slow, but this is the idea: */
for(i = 0; !(b & FLAC__WORD_TOP_BIT_ONE); i++)
@@ -885,9 +888,9 @@
i = ALIGNED_UNARY_BITS(b);
#endif
uval += i;
- bits = parameter;
- i++;
cbits += i;
+ bits = parameter;
+ cbits++; /* skip over stop bit */
FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD);
goto break1;
}