ref: 290c921d1d01119b7d4550770da06c491508508f
dir: /sys/src/cmd/audio/libFLAC/bitreader.c/
/* libFLAC - Free Lossless Audio Codec library * Copyright (C) 2000-2009 Josh Coalson * Copyright (C) 2011-2018 Xiph.Org Foundation * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of the Xiph.org Foundation nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifdef HAVE_CONFIG_H # include <config.h> #endif #include <stdlib.h> #include <string.h> #include "private/bitmath.h" #include "private/bitreader.h" #include "private/crc.h" #include "private/macros.h" #include "FLAC/assert.h" #include "share/compat.h" #include "share/endswap.h" /* Things should be fastest when this matches the machine word size */ /* WATCHOUT: if you change this you must also change the following #defines down to COUNT_ZERO_MSBS2 below to match */ /* WATCHOUT: there are a few places where the code will not work unless brword is >= 32 bits wide */ /* also, some sections currently only have fast versions for 4 or 8 bytes per word */ #if (ENABLE_64_BIT_WORDS == 0) typedef FLAC__uint32 brword; #define FLAC__BYTES_PER_WORD 4 /* sizeof brword */ #define FLAC__BITS_PER_WORD 32 #define FLAC__WORD_ALL_ONES ((FLAC__uint32)0xffffffff) /* SWAP_BE_WORD_TO_HOST swaps bytes in a brword (which is always big-endian) if necessary to match host byte order */ #if WORDS_BIGENDIAN #define SWAP_BE_WORD_TO_HOST(x) (x) #else #define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_32(x) #endif /* counts the # of zero MSBs in a word */ #define COUNT_ZERO_MSBS(word) FLAC__clz_uint32(word) #define COUNT_ZERO_MSBS2(word) FLAC__clz2_uint32(word) #else typedef FLAC__uint64 brword; #define FLAC__BYTES_PER_WORD 8 /* sizeof brword */ #define FLAC__BITS_PER_WORD 64 #define FLAC__WORD_ALL_ONES ((FLAC__uint64)FLAC__U64L(0xffffffffffffffff)) /* SWAP_BE_WORD_TO_HOST swaps bytes in a brword (which is always big-endian) if necessary to match host byte order */ #if WORDS_BIGENDIAN #define SWAP_BE_WORD_TO_HOST(x) (x) #else #define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_64(x) #endif /* counts the # of zero MSBs in a word */ #define COUNT_ZERO_MSBS(word) FLAC__clz_uint64(word) #define COUNT_ZERO_MSBS2(word) FLAC__clz2_uint64(word) #endif /* * This should be at least twice as large as the largest number of words * required to represent any 'number' (in any encoding) you are going to * read. With FLAC this is on the order of maybe a few hundred bits. * If the buffer is smaller than that, the decoder won't be able to read * in a whole number that is in a variable length encoding (e.g. Rice). * But to be practical it should be at least 1K bytes. * * Increase this number to decrease the number of read callbacks, at the * expense of using more memory. Or decrease for the reverse effect, * keeping in mind the limit from the first paragraph. The optimal size * also depends on the CPU cache size and other factors; some twiddling * may be necessary to squeeze out the best performance. */ static const uint32_t FLAC__BITREADER_DEFAULT_CAPACITY = 65536u / FLAC__BITS_PER_WORD; /* in words */ 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 */ brword *buffer; uint32_t capacity; /* in words */ uint32_t words; /* # of completed words in buffer */ uint32_t bytes; /* # of bytes in incomplete word at buffer[words] */ uint32_t consumed_words; /* #words ... */ uint32_t consumed_bits; /* ... + (#bits of head word) already consumed from the front of buffer */ uint32_t read_crc16; /* the running frame CRC */ uint32_t crc16_offset; /* the number of words in the current buffer that should not be CRC'd */ uint32_t crc16_align; /* the number of bits in the current consumed word that should not be CRC'd */ FLAC__BitReaderReadCallback read_callback; void *client_data; }; static inline void crc16_update_word_(FLAC__BitReader *br, brword word) { register uint32_t crc = br->read_crc16; for( ; br->crc16_align < FLAC__BITS_PER_WORD; br->crc16_align += 8) crc = FLAC__CRC16_UPDATE((uint32_t)((word >> (FLAC__BITS_PER_WORD-8-br->crc16_align)) & 0xff), crc); br->read_crc16 = crc; br->crc16_align = 0; } static inline void crc16_update_block_(FLAC__BitReader *br) { if(br->consumed_words > br->crc16_offset && br->crc16_align) crc16_update_word_(br, br->buffer[br->crc16_offset++]); #if FLAC__BYTES_PER_WORD == 4 br->read_crc16 = FLAC__crc16_update_words32(br->buffer + br->crc16_offset, br->consumed_words - br->crc16_offset, br->read_crc16); #elif FLAC__BYTES_PER_WORD == 8 br->read_crc16 = FLAC__crc16_update_words64(br->buffer + br->crc16_offset, br->consumed_words - br->crc16_offset, br->read_crc16); #else unsigned i; for(i = br->crc16_offset; i < br->consumed_words; i++) crc16_update_word_(br, br->buffer[i]); #endif br->crc16_offset = 0; } static FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br) { uint32_t start, end; size_t bytes; FLAC__byte *target; /* first shift the unconsumed buffer data toward the front as much as possible */ if(br->consumed_words > 0) { crc16_update_block_(br); /* CRC consumed words */ start = br->consumed_words; end = br->words + (br->bytes? 1:0); memmove(br->buffer, br->buffer+start, FLAC__BYTES_PER_WORD * (end - start)); br->words -= start; br->consumed_words = 0; } /* * set the target for reading, taking into account word alignment and endianness */ bytes = (br->capacity - br->words) * FLAC__BYTES_PER_WORD - br->bytes; if(bytes == 0) return false; /* no space left, buffer is too small; see note for FLAC__BITREADER_DEFAULT_CAPACITY */ target = ((FLAC__byte*)(br->buffer+br->words)) + br->bytes; /* before reading, if the existing reader looks like this (say brword is 32 bits wide) * bitstream : 11 22 33 44 55 br->words=1 br->bytes=1 (partial tail word is left-justified) * buffer[BE]: 11 22 33 44 55 ?? ?? ?? (shown laid out as bytes sequentially in memory) * buffer[LE]: 44 33 22 11 ?? ?? ?? 55 (?? being don't-care) * ^^-------target, bytes=3 * on LE machines, have to byteswap the odd tail word so nothing is * overwritten: */ #if WORDS_BIGENDIAN #else if(br->bytes) br->buffer[br->words] = SWAP_BE_WORD_TO_HOST(br->buffer[br->words]); #endif /* now it looks like: * bitstream : 11 22 33 44 55 br->words=1 br->bytes=1 * buffer[BE]: 11 22 33 44 55 ?? ?? ?? * buffer[LE]: 44 33 22 11 55 ?? ?? ?? * ^^-------target, bytes=3 */ /* read in the data; note that the callback may return a smaller number of bytes */ if(!br->read_callback(target, &bytes, br->client_data)) return false; /* after reading bytes 66 77 88 99 AA BB CC DD EE FF from the client: * bitstream : 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF * buffer[BE]: 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF ?? * buffer[LE]: 44 33 22 11 55 66 77 88 99 AA BB CC DD EE FF ?? * now have to byteswap on LE machines: */ #if WORDS_BIGENDIAN #else end = (br->words*FLAC__BYTES_PER_WORD + br->bytes + (uint32_t)bytes + (FLAC__BYTES_PER_WORD-1)) / FLAC__BYTES_PER_WORD; for(start = br->words; start < end; start++) br->buffer[start] = SWAP_BE_WORD_TO_HOST(br->buffer[start]); #endif /* now it looks like: * bitstream : 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF * buffer[BE]: 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF ?? * buffer[LE]: 44 33 22 11 88 77 66 55 CC BB AA 99 ?? FF EE DD * finally we'll update the reader values: */ end = br->words*FLAC__BYTES_PER_WORD + br->bytes + (uint32_t)bytes; br->words = end / FLAC__BYTES_PER_WORD; br->bytes = end % FLAC__BYTES_PER_WORD; return true; } /*********************************************************************** * * Class constructor/destructor * ***********************************************************************/ FLAC__BitReader *FLAC__bitreader_new(void) { FLAC__BitReader *br = calloc(1, sizeof(FLAC__BitReader)); /* calloc() implies: memset(br, 0, sizeof(FLAC__BitReader)); br->buffer = 0; br->capacity = 0; br->words = br->bytes = 0; br->consumed_words = br->consumed_bits = 0; br->read_callback = 0; br->client_data = 0; */ return br; } void FLAC__bitreader_delete(FLAC__BitReader *br) { FLAC__ASSERT(0 != br); FLAC__bitreader_free(br); free(br); } /*********************************************************************** * * Public class methods * ***********************************************************************/ FLAC__bool FLAC__bitreader_init(FLAC__BitReader *br, FLAC__BitReaderReadCallback rcb, void *cd) { FLAC__ASSERT(0 != br); br->words = br->bytes = 0; br->consumed_words = br->consumed_bits = 0; br->capacity = FLAC__BITREADER_DEFAULT_CAPACITY; br->buffer = malloc(sizeof(brword) * br->capacity); if(br->buffer == 0) return false; br->read_callback = rcb; br->client_data = cd; return true; } void FLAC__bitreader_free(FLAC__BitReader *br) { FLAC__ASSERT(0 != br); if(0 != br->buffer) free(br->buffer); br->buffer = 0; br->capacity = 0; br->words = br->bytes = 0; br->consumed_words = br->consumed_bits = 0; br->read_callback = 0; br->client_data = 0; } FLAC__bool FLAC__bitreader_clear(FLAC__BitReader *br) { br->words = br->bytes = 0; br->consumed_words = br->consumed_bits = 0; return true; } void FLAC__bitreader_dump(const FLAC__BitReader *br, FILE *out) { uint32_t i, j; if(br == 0) { fprintf(out, "bitreader is NULL\n"); } else { fprintf(out, "bitreader: capacity=%u words=%u bytes=%u consumed: words=%u, bits=%u\n", br->capacity, br->words, br->bytes, br->consumed_words, br->consumed_bits); for(i = 0; i < br->words; i++) { fprintf(out, "%08X: ", i); for(j = 0; j < FLAC__BITS_PER_WORD; j++) if(i < br->consumed_words || (i == br->consumed_words && j < br->consumed_bits)) fprintf(out, "."); else fprintf(out, "%01d", br->buffer[i] & ((brword)1 << (FLAC__BITS_PER_WORD-j-1)) ? 1:0); fprintf(out, "\n"); } if(br->bytes > 0) { fprintf(out, "%08X: ", i); for(j = 0; j < br->bytes*8; j++) if(i < br->consumed_words || (i == br->consumed_words && j < br->consumed_bits)) fprintf(out, "."); else fprintf(out, "%01d", br->buffer[i] & ((brword)1 << (br->bytes*8-j-1)) ? 1:0); fprintf(out, "\n"); } } } void FLAC__bitreader_reset_read_crc16(FLAC__BitReader *br, FLAC__uint16 seed) { FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); FLAC__ASSERT((br->consumed_bits & 7) == 0); br->read_crc16 = (uint32_t)seed; br->crc16_offset = br->consumed_words; br->crc16_align = br->consumed_bits; } FLAC__uint16 FLAC__bitreader_get_read_crc16(FLAC__BitReader *br) { FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); /* CRC consumed words up to here */ crc16_update_block_(br); FLAC__ASSERT((br->consumed_bits & 7) == 0); FLAC__ASSERT(br->crc16_align <= br->consumed_bits); /* CRC any tail bytes in a partially-consumed word */ if(br->consumed_bits) { const brword tail = br->buffer[br->consumed_words]; for( ; br->crc16_align < br->consumed_bits; br->crc16_align += 8) br->read_crc16 = FLAC__CRC16_UPDATE((uint32_t)((tail >> (FLAC__BITS_PER_WORD-8-br->crc16_align)) & 0xff), br->read_crc16); } return br->read_crc16; } inline FLAC__bool FLAC__bitreader_is_consumed_byte_aligned(const FLAC__BitReader *br) { return ((br->consumed_bits & 7) == 0); } inline uint32_t FLAC__bitreader_bits_left_for_byte_alignment(const FLAC__BitReader *br) { return 8 - (br->consumed_bits & 7); } inline uint32_t FLAC__bitreader_get_input_bits_unconsumed(const FLAC__BitReader *br) { return (br->words-br->consumed_words)*FLAC__BITS_PER_WORD + br->bytes*8 - br->consumed_bits; } FLAC__bool FLAC__bitreader_read_raw_uint32(FLAC__BitReader *br, FLAC__uint32 *val, uint32_t bits) { FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); FLAC__ASSERT(bits <= 32); FLAC__ASSERT((br->capacity*FLAC__BITS_PER_WORD) * 2 >= bits); FLAC__ASSERT(br->consumed_words <= br->words); /* WATCHOUT: code does not work with <32bit words; we can make things much faster with this assertion */ FLAC__ASSERT(FLAC__BITS_PER_WORD >= 32); if(bits == 0) { /* OPT: investigate if this can ever happen, maybe change to assertion */ *val = 0; return true; } while((br->words-br->consumed_words)*FLAC__BITS_PER_WORD + br->bytes*8 - br->consumed_bits < bits) { if(!bitreader_read_from_client_(br)) return false; } if(br->consumed_words < br->words) { /* if we've not consumed up to a partial tail word... */ /* OPT: taking out the consumed_bits==0 "else" case below might make things faster if less code allows the compiler to inline this function */ if(br->consumed_bits) { /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */ const uint32_t n = FLAC__BITS_PER_WORD - br->consumed_bits; const brword word = br->buffer[br->consumed_words]; if(bits < n) { *val = (FLAC__uint32)((word & (FLAC__WORD_ALL_ONES >> br->consumed_bits)) >> (n-bits)); /* The result has <= 32 non-zero bits */ br->consumed_bits += bits; return true; } /* (FLAC__BITS_PER_WORD - br->consumed_bits <= bits) ==> (FLAC__WORD_ALL_ONES >> br->consumed_bits) has no more than 'bits' non-zero bits */ *val = (FLAC__uint32)(word & (FLAC__WORD_ALL_ONES >> br->consumed_bits)); bits -= n; br->consumed_words++; br->consumed_bits = 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 */ *val <<= bits; *val |= (FLAC__uint32)(br->buffer[br->consumed_words] >> (FLAC__BITS_PER_WORD-bits)); br->consumed_bits = bits; } return true; } else { /* br->consumed_bits == 0 */ const brword word = br->buffer[br->consumed_words]; if(bits < FLAC__BITS_PER_WORD) { *val = (FLAC__uint32)(word >> (FLAC__BITS_PER_WORD-bits)); br->consumed_bits = bits; return true; } /* at this point bits == FLAC__BITS_PER_WORD == 32; because of previous assertions, it can't be larger */ *val = (FLAC__uint32)word; br->consumed_words++; return true; } } else { /* in this case we're starting our read at a partial tail word; * the reader has guaranteed that we have at least 'bits' bits * available to read, which makes this case simpler. */ /* OPT: taking out the consumed_bits==0 "else" case below might make things faster if less code allows the compiler to inline this function */ if(br->consumed_bits) { /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */ FLAC__ASSERT(br->consumed_bits + bits <= br->bytes*8); *val = (FLAC__uint32)((br->buffer[br->consumed_words] & (FLAC__WORD_ALL_ONES >> br->consumed_bits)) >> (FLAC__BITS_PER_WORD-br->consumed_bits-bits)); br->consumed_bits += bits; return true; } else { *val = (FLAC__uint32)(br->buffer[br->consumed_words] >> (FLAC__BITS_PER_WORD-bits)); br->consumed_bits += bits; return true; } } } FLAC__bool FLAC__bitreader_read_raw_int32(FLAC__BitReader *br, FLAC__int32 *val, uint32_t bits) { FLAC__uint32 uval, mask; /* OPT: inline raw uint32 code here, or make into a macro if possible in the .h file */ if(!FLAC__bitreader_read_raw_uint32(br, &uval, bits)) return false; /* sign-extend *val assuming it is currently bits wide. */ /* From: https://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend */ mask = 1u << (bits - 1); *val = (uval ^ mask) - mask; return true; } FLAC__bool FLAC__bitreader_read_raw_uint64(FLAC__BitReader *br, FLAC__uint64 *val, uint32_t bits) { FLAC__uint32 hi, lo; if(bits > 32) { if(!FLAC__bitreader_read_raw_uint32(br, &hi, bits-32)) return false; if(!FLAC__bitreader_read_raw_uint32(br, &lo, 32)) return false; *val = hi; *val <<= 32; *val |= lo; } else { if(!FLAC__bitreader_read_raw_uint32(br, &lo, bits)) return false; *val = lo; } return true; } inline FLAC__bool FLAC__bitreader_read_uint32_little_endian(FLAC__BitReader *br, FLAC__uint32 *val) { FLAC__uint32 x8, x32 = 0; /* this doesn't need to be that fast as currently it is only used for vorbis comments */ if(!FLAC__bitreader_read_raw_uint32(br, &x32, 8)) return false; if(!FLAC__bitreader_read_raw_uint32(br, &x8, 8)) return false; x32 |= (x8 << 8); if(!FLAC__bitreader_read_raw_uint32(br, &x8, 8)) return false; x32 |= (x8 << 16); if(!FLAC__bitreader_read_raw_uint32(br, &x8, 8)) return false; x32 |= (x8 << 24); *val = x32; return true; } FLAC__bool FLAC__bitreader_skip_bits_no_crc(FLAC__BitReader *br, uint32_t bits) { /* * OPT: a faster implementation is possible but probably not that useful * since this is only called a couple of times in the metadata readers. */ FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); if(bits > 0) { const uint32_t n = br->consumed_bits & 7; uint32_t m; FLAC__uint32 x; if(n != 0) { m = flac_min(8-n, bits); if(!FLAC__bitreader_read_raw_uint32(br, &x, m)) return false; bits -= m; } m = bits / 8; if(m > 0) { if(!FLAC__bitreader_skip_byte_block_aligned_no_crc(br, m)) return false; bits %= 8; } if(bits > 0) { if(!FLAC__bitreader_read_raw_uint32(br, &x, bits)) return false; } } return true; } FLAC__bool FLAC__bitreader_skip_byte_block_aligned_no_crc(FLAC__BitReader *br, uint32_t nvals) { FLAC__uint32 x; FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); FLAC__ASSERT(FLAC__bitreader_is_consumed_byte_aligned(br)); /* step 1: skip over partial head word to get word aligned */ while(nvals && br->consumed_bits) { /* i.e. run until we read 'nvals' bytes or we hit the end of the head word */ if(!FLAC__bitreader_read_raw_uint32(br, &x, 8)) return false; nvals--; } if(0 == nvals) return true; /* step 2: skip whole words in chunks */ while(nvals >= FLAC__BYTES_PER_WORD) { if(br->consumed_words < br->words) { br->consumed_words++; nvals -= FLAC__BYTES_PER_WORD; } else if(!bitreader_read_from_client_(br)) return false; } /* step 3: skip any remainder from partial tail bytes */ while(nvals) { if(!FLAC__bitreader_read_raw_uint32(br, &x, 8)) return false; nvals--; } return true; } FLAC__bool FLAC__bitreader_read_byte_block_aligned_no_crc(FLAC__BitReader *br, FLAC__byte *val, uint32_t nvals) { FLAC__uint32 x; FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); FLAC__ASSERT(FLAC__bitreader_is_consumed_byte_aligned(br)); /* step 1: read from partial head word to get word aligned */ while(nvals && br->consumed_bits) { /* i.e. run until we read 'nvals' bytes or we hit the end of the head word */ if(!FLAC__bitreader_read_raw_uint32(br, &x, 8)) return false; *val++ = (FLAC__byte)x; nvals--; } if(0 == nvals) return true; /* step 2: read whole words in chunks */ while(nvals >= FLAC__BYTES_PER_WORD) { if(br->consumed_words < br->words) { const brword word = br->buffer[br->consumed_words++]; #if FLAC__BYTES_PER_WORD == 4 val[0] = (FLAC__byte)(word >> 24); val[1] = (FLAC__byte)(word >> 16); val[2] = (FLAC__byte)(word >> 8); val[3] = (FLAC__byte)word; #elif FLAC__BYTES_PER_WORD == 8 val[0] = (FLAC__byte)(word >> 56); val[1] = (FLAC__byte)(word >> 48); val[2] = (FLAC__byte)(word >> 40); val[3] = (FLAC__byte)(word >> 32); val[4] = (FLAC__byte)(word >> 24); val[5] = (FLAC__byte)(word >> 16); val[6] = (FLAC__byte)(word >> 8); val[7] = (FLAC__byte)word; #else for(x = 0; x < FLAC__BYTES_PER_WORD; x++) val[x] = (FLAC__byte)(word >> (8*(FLAC__BYTES_PER_WORD-x-1))); #endif val += FLAC__BYTES_PER_WORD; nvals -= FLAC__BYTES_PER_WORD; } else if(!bitreader_read_from_client_(br)) return false; } /* step 3: read any remainder from partial tail bytes */ while(nvals) { if(!FLAC__bitreader_read_raw_uint32(br, &x, 8)) return false; *val++ = (FLAC__byte)x; nvals--; } return true; } FLAC__bool FLAC__bitreader_read_unary_unsigned(FLAC__BitReader *br, uint32_t *val) #if 0 /* slow but readable version */ { uint32_t bit; FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); *val = 0; while(1) { if(!FLAC__bitreader_read_bit(br, &bit)) return false; if(bit) break; else *val++; } return true; } #else { uint32_t i; FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); *val = 0; while(1) { while(br->consumed_words < br->words) { /* if we've not consumed up to a partial tail word... */ brword b = br->buffer[br->consumed_words] << br->consumed_bits; if(b) { i = COUNT_ZERO_MSBS(b); *val += i; i++; br->consumed_bits += i; if(br->consumed_bits >= FLAC__BITS_PER_WORD) { /* faster way of testing if(br->consumed_bits == FLAC__BITS_PER_WORD) */ br->consumed_words++; br->consumed_bits = 0; } return true; } else { *val += FLAC__BITS_PER_WORD - br->consumed_bits; br->consumed_words++; br->consumed_bits = 0; /* didn't find stop bit yet, have to keep going... */ } } /* at this point we've eaten up all the whole words; have to try * reading through any tail bytes before calling the read callback. * this is a repeat of the above logic adjusted for the fact we * don't have a whole word. note though if the client is feeding * us data a byte at a time (unlikely), br->consumed_bits may not * be zero. */ if(br->bytes*8 > br->consumed_bits) { const uint32_t end = br->bytes * 8; brword b = (br->buffer[br->consumed_words] & (FLAC__WORD_ALL_ONES << (FLAC__BITS_PER_WORD-end))) << br->consumed_bits; if(b) { i = COUNT_ZERO_MSBS(b); *val += i; i++; br->consumed_bits += i; FLAC__ASSERT(br->consumed_bits < FLAC__BITS_PER_WORD); return true; } else { *val += end - br->consumed_bits; br->consumed_bits = end; FLAC__ASSERT(br->consumed_bits < FLAC__BITS_PER_WORD); /* didn't find stop bit yet, have to keep going... */ } } if(!bitreader_read_from_client_(br)) return false; } } #endif FLAC__bool FLAC__bitreader_read_rice_signed(FLAC__BitReader *br, int *val, uint32_t parameter) { FLAC__uint32 lsbs = 0, msbs = 0; uint32_t uval; FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); FLAC__ASSERT(parameter <= 31); /* read the unary MSBs and end bit */ if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) return false; /* read the binary LSBs */ if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, parameter)) return false; /* compose the value */ uval = (msbs << parameter) | lsbs; if(uval & 1) *val = -((int)(uval >> 1)) - 1; else *val = (int)(uval >> 1); return true; } /* this is by far the most heavily used reader call. it ain't pretty but it's fast */ FLAC__bool FLAC__bitreader_read_rice_signed_block(FLAC__BitReader *br, int vals[], uint32_t nvals, uint32_t parameter) { /* try and get br->consumed_words and br->consumed_bits into register; * must remember to flush them back to *br before calling other * bitreader functions that use them, and before returning */ uint32_t cwords, words, lsbs, msbs, x, y; uint32_t ucbits; /* keep track of the number of unconsumed bits in word */ brword b; int *val, *end; FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); /* 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 than 2 words, so we don't have to loop to read it */ val = vals; end = vals + nvals; if(parameter == 0) { while(val < end) { /* read the unary MSBs and end bit */ if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) return false; *val++ = (int)(msbs >> 1) ^ -(int)(msbs & 1); } return true; } FLAC__ASSERT(parameter > 0); cwords = br->consumed_words; words = br->words; /* if we've not consumed up to a partial tail word... */ if(cwords >= words) { x = 0; goto process_tail; } ucbits = FLAC__BITS_PER_WORD - br->consumed_bits; b = br->buffer[cwords] << br->consumed_bits; /* keep unconsumed bits aligned to left */ while(val < end) { /* read the unary MSBs and end bit */ x = y = COUNT_ZERO_MSBS2(b); if(x == FLAC__BITS_PER_WORD) { x = ucbits; do { /* didn't find stop bit yet, have to keep going... */ cwords++; if (cwords >= words) goto incomplete_msbs; b = br->buffer[cwords]; y = COUNT_ZERO_MSBS2(b); x += y; } while(y == FLAC__BITS_PER_WORD); } b <<= y; b <<= 1; /* account for stop bit */ ucbits = (ucbits - x - 1) % FLAC__BITS_PER_WORD; msbs = x; /* read the binary LSBs */ x = (FLAC__uint32)(b >> (FLAC__BITS_PER_WORD - parameter)); /* parameter < 32, so we can cast to 32-bit uint32_t */ if(parameter <= ucbits) { ucbits -= parameter; b <<= parameter; } else { /* there are still bits left to read, they will all be in the next word */ cwords++; if (cwords >= words) goto incomplete_lsbs; b = br->buffer[cwords]; ucbits += FLAC__BITS_PER_WORD - parameter; x |= (FLAC__uint32)(b >> ucbits); b <<= FLAC__BITS_PER_WORD - ucbits; } lsbs = x; /* compose the value */ x = (msbs << parameter) | lsbs; *val++ = (int)(x >> 1) ^ -(int)(x & 1); continue; /* at this point we've eaten up all the whole words */ process_tail: do { if(0) { incomplete_msbs: br->consumed_bits = 0; br->consumed_words = cwords; } /* read the unary MSBs and end bit */ if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) return false; msbs += x; x = ucbits = 0; if(0) { incomplete_lsbs: br->consumed_bits = 0; br->consumed_words = cwords; } /* read the binary LSBs */ if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, parameter - ucbits)) return false; lsbs = x | lsbs; /* compose the value */ x = (msbs << parameter) | lsbs; *val++ = (int)(x >> 1) ^ -(int)(x & 1); x = 0; cwords = br->consumed_words; words = br->words; ucbits = FLAC__BITS_PER_WORD - br->consumed_bits; b = br->buffer[cwords] << br->consumed_bits; } while(cwords >= words && val < end); } if(ucbits == 0 && cwords < words) { /* don't leave the head word with no unconsumed bits */ cwords++; ucbits = FLAC__BITS_PER_WORD; } br->consumed_bits = FLAC__BITS_PER_WORD - ucbits; br->consumed_words = cwords; return true; } #if 0 /* UNUSED */ FLAC__bool FLAC__bitreader_read_golomb_signed(FLAC__BitReader *br, int *val, uint32_t parameter) { FLAC__uint32 lsbs = 0, msbs = 0; uint32_t bit, uval, k; FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); k = FLAC__bitmath_ilog2(parameter); /* read the unary MSBs and end bit */ if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) return false; /* read the binary LSBs */ if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, k)) return false; if(parameter == 1u<<k) { /* compose the value */ uval = (msbs << k) | lsbs; } else { uint32_t d = (1 << (k+1)) - parameter; if(lsbs >= d) { if(!FLAC__bitreader_read_bit(br, &bit)) return false; lsbs <<= 1; lsbs |= bit; lsbs -= d; } /* compose the value */ uval = msbs * parameter + lsbs; } /* unfold uint32_t to signed */ if(uval & 1) *val = -((int)(uval >> 1)) - 1; else *val = (int)(uval >> 1); return true; } FLAC__bool FLAC__bitreader_read_golomb_unsigned(FLAC__BitReader *br, uint32_t *val, uint32_t parameter) { FLAC__uint32 lsbs, msbs = 0; uint32_t bit, k; FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); k = FLAC__bitmath_ilog2(parameter); /* read the unary MSBs and end bit */ if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) return false; /* read the binary LSBs */ if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, k)) return false; if(parameter == 1u<<k) { /* compose the value */ *val = (msbs << k) | lsbs; } else { uint32_t d = (1 << (k+1)) - parameter; if(lsbs >= d) { if(!FLAC__bitreader_read_bit(br, &bit)) return false; lsbs <<= 1; lsbs |= bit; lsbs -= d; } /* compose the value */ *val = msbs * parameter + lsbs; } return true; } #endif /* UNUSED */ /* on return, if *val == 0xffffffff then the utf-8 sequence was invalid, but the return value will be true */ FLAC__bool FLAC__bitreader_read_utf8_uint32(FLAC__BitReader *br, FLAC__uint32 *val, FLAC__byte *raw, uint32_t *rawlen) { FLAC__uint32 v = 0; FLAC__uint32 x; uint32_t i; if(!FLAC__bitreader_read_raw_uint32(br, &x, 8)) return false; if(raw) raw[(*rawlen)++] = (FLAC__byte)x; if(!(x & 0x80)) { /* 0xxxxxxx */ v = x; i = 0; } else if(x & 0xC0 && !(x & 0x20)) { /* 110xxxxx */ v = x & 0x1F; i = 1; } else if(x & 0xE0 && !(x & 0x10)) { /* 1110xxxx */ v = x & 0x0F; i = 2; } else if(x & 0xF0 && !(x & 0x08)) { /* 11110xxx */ v = x & 0x07; i = 3; } else if(x & 0xF8 && !(x & 0x04)) { /* 111110xx */ v = x & 0x03; i = 4; } else if(x & 0xFC && !(x & 0x02)) { /* 1111110x */ v = x & 0x01; i = 5; } else { *val = 0xffffffff; return true; } for( ; i; i--) { if(!FLAC__bitreader_read_raw_uint32(br, &x, 8)) return false; if(raw) raw[(*rawlen)++] = (FLAC__byte)x; if(!(x & 0x80) || (x & 0x40)) { /* 10xxxxxx */ *val = 0xffffffff; return true; } v <<= 6; v |= (x & 0x3F); } *val = v; return true; } /* on return, if *val == 0xffffffffffffffff then the utf-8 sequence was invalid, but the return value will be true */ FLAC__bool FLAC__bitreader_read_utf8_uint64(FLAC__BitReader *br, FLAC__uint64 *val, FLAC__byte *raw, uint32_t *rawlen) { FLAC__uint64 v = 0; FLAC__uint32 x; uint32_t i; if(!FLAC__bitreader_read_raw_uint32(br, &x, 8)) return false; if(raw) raw[(*rawlen)++] = (FLAC__byte)x; if(!(x & 0x80)) { /* 0xxxxxxx */ v = x; i = 0; } else if(x & 0xC0 && !(x & 0x20)) { /* 110xxxxx */ v = x & 0x1F; i = 1; } else if(x & 0xE0 && !(x & 0x10)) { /* 1110xxxx */ v = x & 0x0F; i = 2; } else if(x & 0xF0 && !(x & 0x08)) { /* 11110xxx */ v = x & 0x07; i = 3; } else if(x & 0xF8 && !(x & 0x04)) { /* 111110xx */ v = x & 0x03; i = 4; } else if(x & 0xFC && !(x & 0x02)) { /* 1111110x */ v = x & 0x01; i = 5; } else if(x & 0xFE && !(x & 0x01)) { /* 11111110 */ v = 0; i = 6; } else { *val = FLAC__U64L(0xffffffffffffffff); return true; } for( ; i; i--) { if(!FLAC__bitreader_read_raw_uint32(br, &x, 8)) return false; if(raw) raw[(*rawlen)++] = (FLAC__byte)x; if(!(x & 0x80) || (x & 0x40)) { /* 10xxxxxx */ *val = FLAC__U64L(0xffffffffffffffff); return true; } v <<= 6; v |= (x & 0x3F); } *val = v; return true; } /* These functions are declared inline in this file but are also callable as * externs from elsewhere. * According to the C99 spec, section 6.7.4, simply providing a function * prototype in a header file without 'inline' and making the function inline * in this file should be sufficient. * Unfortunately, the Microsoft VS compiler doesn't pick them up externally. To * fix that we add extern declarations here. */ extern FLAC__bool FLAC__bitreader_is_consumed_byte_aligned(const FLAC__BitReader *br); extern uint32_t FLAC__bitreader_bits_left_for_byte_alignment(const FLAC__BitReader *br); extern uint32_t FLAC__bitreader_get_input_bits_unconsumed(const FLAC__BitReader *br); extern FLAC__bool FLAC__bitreader_read_uint32_little_endian(FLAC__BitReader *br, FLAC__uint32 *val);