minor optimizations to FLAC__bitreader_read_rice_signed_block()

diff --git a/src/libFLAC/bitreader.c b/src/libFLAC/bitreader.c
index e02a03f..47aa403 100644 (file)
--- a/src/libFLAC/bitreader.c
+++ b/src/libFLAC/bitreader.c
@@ -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;
                                }
                        }