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Diffstat (limited to 'src/libFLAC/bitreader.c')
| -rw-r--r-- | src/libFLAC/bitreader.c | 1052 |
1 files changed, 1052 insertions, 0 deletions
diff --git a/src/libFLAC/bitreader.c b/src/libFLAC/bitreader.c new file mode 100644 index 0000000..829b308 --- /dev/null +++ b/src/libFLAC/bitreader.c @@ -0,0 +1,1052 @@ +/* libFLAC - Free Lossless Audio Codec library + * Copyright (C) 2000-2009 Josh Coalson + * Copyright (C) 2011-2023 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/cpu.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__bool read_limit_set; /* whether reads are limited */ + uint32_t read_limit; /* the remaining size of what can be read */ + uint32_t last_seen_framesync; /* the location of the last seen framesync, if it is in the buffer, in bits from front of buffer */ + 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) { + uint32_t shift = FLAC__BITS_PER_WORD - 8 - br->crc16_align ; + crc = FLAC__CRC16_UPDATE ((uint32_t) (shift < FLAC__BITS_PER_WORD ? (word >> shift) & 0xff : 0), 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++]); + + /* Prevent OOB read due to wrap-around. */ + if (br->consumed_words > 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; +#if WORDS_BIGENDIAN +#else + brword preswap_backup; +#endif + + /* first shift the unconsumed buffer data toward the front as much as possible */ + if(br->consumed_words > 0) { + /* invalidate last seen framesync */ + br->last_seen_framesync = -1; + + 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 + preswap_backup = br->buffer[br->words]; + 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)){ + /* Despite the read callback failing, the data in the target + * might be used later, when the buffer is rewound. Therefore + * we revert the swap that was just done */ +#if WORDS_BIGENDIAN +#else + br->buffer[br->words] = preswap_backup; +#endif + 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; + br->read_limit_set = false; + br->read_limit = -1; + br->last_seen_framesync = -1; + + 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; + br->read_limit_set = false; + br->read_limit = -1; + br->last_seen_framesync = -1; +} + +FLAC__bool FLAC__bitreader_clear(FLAC__BitReader *br) +{ + br->words = br->bytes = 0; + br->consumed_words = br->consumed_bits = 0; + br->read_limit_set = false; + br->read_limit = -1; + br->last_seen_framesync = -1; + return true; +} + +void FLAC__bitreader_set_framesync_location(FLAC__BitReader *br) +{ + br->last_seen_framesync = br->consumed_words * FLAC__BYTES_PER_WORD + br->consumed_bits / 8; +} + +FLAC__bool FLAC__bitreader_rewind_to_after_last_seen_framesync(FLAC__BitReader *br) +{ + if(br->last_seen_framesync == (uint32_t)-1) { + br->consumed_words = br->consumed_bits = 0; + return false; + } + else { + br->consumed_words = (br->last_seen_framesync + 1) / FLAC__BYTES_PER_WORD; + br->consumed_bits = ((br->last_seen_framesync + 1) % FLAC__BYTES_PER_WORD) * 8; + return true; + } +} + +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; +} + +void FLAC__bitreader_set_limit(FLAC__BitReader *br, uint32_t limit) +{ + br->read_limit = limit; + br->read_limit_set = true; +} + +void FLAC__bitreader_remove_limit(FLAC__BitReader *br) +{ + br->read_limit_set = false; + br->read_limit = -1; +} + +uint32_t FLAC__bitreader_limit_remaining(FLAC__BitReader *br) +{ + FLAC__ASSERT(br->read_limit_set); + return br->read_limit; +} +void FLAC__bitreader_limit_invalidate(FLAC__BitReader *br) +{ + br->read_limit = -1; +} + +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; + } + + if(br->read_limit_set && br->read_limit < (uint32_t)-1){ + if(br->read_limit < bits) { + br->read_limit = -1; + return false; + } + else + br->read_limit -= bits; + } + + 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]; + const brword mask = br->consumed_bits < FLAC__BITS_PER_WORD ? FLAC__WORD_ALL_ONES >> br->consumed_bits : 0; + if(bits < n) { + uint32_t shift = n - bits; + *val = shift < FLAC__BITS_PER_WORD ? (FLAC__uint32)((word & mask) >> shift) : 0; /* 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 & mask); + 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 */ + uint32_t shift = FLAC__BITS_PER_WORD - bits; + *val = bits < 32 ? *val << bits : 0; + *val |= shift < FLAC__BITS_PER_WORD ? (FLAC__uint32)(br->buffer[br->consumed_words] >> shift) : 0; + 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 (bits < 1 || ! 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 = bits >= 33 ? 0 : 1lu << (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; +} + +FLAC__bool FLAC__bitreader_read_raw_int64(FLAC__BitReader *br, FLAC__int64 *val, uint32_t bits) +{ + FLAC__uint64 uval, mask; + /* OPT: inline raw uint64 code here, or make into a macro if possible in the .h file */ + if (bits < 1 || ! FLAC__bitreader_read_raw_uint64(br, &uval, bits)) + return false; + /* sign-extend *val assuming it is currently bits wide. */ + /* From: https://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend */ + mask = bits >= 65 ? 0 : 1llu << (bits - 1); + *val = (uval ^ mask) - mask; + 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)); + + if(br->read_limit_set && br->read_limit < (uint32_t)-1){ + if(br->read_limit < nvals*8){ + br->read_limit = -1; + return false; + } + } + + /* 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; + if(br->read_limit_set) + br->read_limit -= FLAC__BITS_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)); + + if(br->read_limit_set && br->read_limit < (uint32_t)-1){ + if(br->read_limit < nvals*8){ + br->read_limit = -1; + return false; + } + } + + /* 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; + if(br->read_limit_set) + br->read_limit -= FLAC__BITS_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->consumed_bits < FLAC__BITS_PER_WORD ? br->buffer[br->consumed_words] << br->consumed_bits : 0; + 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 + +#if 0 /* unused */ +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; +} +#endif + +/* 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) +#include "deduplication/bitreader_read_rice_signed_block.c" + +#ifdef FLAC__BMI2_SUPPORTED +FLAC__SSE_TARGET("bmi2") +FLAC__bool FLAC__bitreader_read_rice_signed_block_bmi2(FLAC__BitReader *br, int vals[], uint32_t nvals, uint32_t parameter) +#include "deduplication/bitreader_read_rice_signed_block.c" +#endif + +#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); |