diff options
Diffstat (limited to 'libFLAC/bitreader.c')
-rw-r--r-- | libFLAC/bitreader.c | 629 |
1 files changed, 156 insertions, 473 deletions
diff --git a/libFLAC/bitreader.c b/libFLAC/bitreader.c index 7d63e52..f61229b 100644 --- a/libFLAC/bitreader.c +++ b/libFLAC/bitreader.c @@ -1,5 +1,6 @@ /* libFLAC - Free Lossless Audio Codec library - * Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007 Josh Coalson + * Copyright (C) 2000-2009 Josh Coalson + * Copyright (C) 2011-2014 Xiph.Org Foundation * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -29,53 +30,33 @@ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ -#if HAVE_CONFIG_H +#ifdef HAVE_CONFIG_H # include <config.h> #endif -#include <stdlib.h> /* for malloc() */ -#include <string.h> /* for memcpy(), memset() */ -#ifdef _MSC_VER -#include <winsock.h> /* for ntohl() */ -#elif defined FLAC__SYS_DARWIN -#include <machine/endian.h> /* for ntohl() */ -#elif defined __MINGW32__ -#include <winsock.h> /* for ntohl() */ -#else -#include <netinet/in.h> /* for ntohl() */ -#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_MSBS below to match */ -/* WATCHOUT: there are a few places where the code will not work unless brword is >= 32 bits wide */ +/* WATCHOUT: if you change this you must also change the following #defines down to FLAC__clz_uint32 below to match */ +/* WATCHOUT: there are a few places where the code will not work unless uint32_t is >= 32 bits wide */ /* also, some sections currently only have fast versions for 4 or 8 bytes per word */ -typedef FLAC__uint32 brword; -#define FLAC__BYTES_PER_WORD 4 -#define FLAC__BITS_PER_WORD 32 +#define FLAC__BYTES_PER_WORD 4 /* sizeof uint32_t */ +#define FLAC__BITS_PER_WORD (8 * FLAC__BYTES_PER_WORD) #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 */ +/* SWAP_BE_WORD_TO_HOST swaps bytes in a uint32_t (which is always big-endian) if necessary to match host byte order */ #if WORDS_BIGENDIAN #define SWAP_BE_WORD_TO_HOST(x) (x) #else -#ifdef _MSC_VER -#define SWAP_BE_WORD_TO_HOST(x) local_swap32_(x) -#else -#define SWAP_BE_WORD_TO_HOST(x) ntohl(x) -#endif +#define SWAP_BE_WORD_TO_HOST(x) ENDSWAP_32(x) #endif -/* counts the # of zero MSBs in a word */ -#define COUNT_ZERO_MSBS(word) ( \ - (word) <= 0xffff ? \ - ( (word) <= 0xff? byte_to_unary_table[word] + 24 : byte_to_unary_table[(word) >> 8] + 16 ) : \ - ( (word) <= 0xffffff? byte_to_unary_table[word >> 16] + 8 : byte_to_unary_table[(word) >> 24] ) \ -) -/* this alternate might be slightly faster on some systems/compilers: */ -#define COUNT_ZERO_MSBS2(word) ( (word) <= 0xff ? byte_to_unary_table[word] + 24 : ((word) <= 0xffff ? byte_to_unary_table[(word) >> 8] + 16 : ((word) <= 0xffffff ? byte_to_unary_table[(word) >> 16] + 8 : byte_to_unary_table[(word) >> 24])) ) - /* * This should be at least twice as large as the largest number of words @@ -93,50 +74,10 @@ typedef FLAC__uint32 brword; */ static const unsigned FLAC__BITREADER_DEFAULT_CAPACITY = 65536u / FLAC__BITS_PER_WORD; /* in words */ -static const unsigned char byte_to_unary_table[] = { - 8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, - 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, - 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 -}; - -#ifdef min -#undef min -#endif -#define min(x,y) ((x)<(y)?(x):(y)) -#ifdef max -#undef max -#endif -#define max(x,y) ((x)>(y)?(x):(y)) - -/* adjust for compilers that can't understand using LLU suffix for uint64_t literals */ -#ifdef _MSC_VER -#define FLAC__U64L(x) x -#else -#define FLAC__U64L(x) x##LLU -#endif - -#ifndef FLaC__INLINE -#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 */ - brword *buffer; + uint32_t *buffer; unsigned capacity; /* in words */ unsigned words; /* # of completed words in buffer */ unsigned bytes; /* # of bytes in incomplete word at buffer[words] */ @@ -146,36 +87,9 @@ struct FLAC__BitReader { unsigned crc16_align; /* the number of bits in the current consumed word that should not be CRC'd */ FLAC__BitReaderReadCallback read_callback; void *client_data; - FLAC__CPUInfo cpu_info; }; -#ifdef _MSC_VER -/* OPT: an MSVC built-in would be better */ -static _inline FLAC__uint32 local_swap32_(FLAC__uint32 x) -{ - x = ((x<<8)&0xFF00FF00) | ((x>>8)&0x00FF00FF); - return (x>>16) | (x<<16); -} -static void local_swap32_block_(FLAC__uint32 *start, FLAC__uint32 len) -{ - __asm { - mov edx, start - mov ecx, len - test ecx, ecx -loop1: - jz done1 - mov eax, [edx] - bswap eax - mov [edx], eax - add edx, 4 - dec ecx - jmp short loop1 -done1: - } -} -#endif - -static FLaC__INLINE void crc16_update_word_(FLAC__BitReader *br, brword word) +static inline void crc16_update_word_(FLAC__BitReader *br, uint32_t word) { register unsigned crc = br->read_crc16; #if FLAC__BYTES_PER_WORD == 4 @@ -204,8 +118,7 @@ static FLaC__INLINE void crc16_update_word_(FLAC__BitReader *br, brword word) br->crc16_align = 0; } -/* would be static except it needs to be called by asm routines */ -FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br) +static FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br) { unsigned start, end; size_t bytes; @@ -229,7 +142,7 @@ FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br) 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) + /* before reading, if the existing reader looks like this (say uint32_t 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 layed out as bytes sequentially in memory) * buffer[LE]: 44 33 22 11 ?? ?? ?? 55 (?? being don't-care) @@ -263,13 +176,6 @@ FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br) #if WORDS_BIGENDIAN #else end = (br->words*FLAC__BYTES_PER_WORD + br->bytes + bytes + (FLAC__BYTES_PER_WORD-1)) / FLAC__BYTES_PER_WORD; -# if defined(_MSC_VER) && (FLAC__BYTES_PER_WORD == 4) - if(br->cpu_info.type == FLAC__CPUINFO_TYPE_IA32 && br->cpu_info.data.ia32.bswap) { - start = br->words; - local_swap32_block_(br->buffer + start, end - start); - } - else -# endif for(start = br->words; start < end; start++) br->buffer[start] = SWAP_BE_WORD_TO_HOST(br->buffer[start]); #endif @@ -295,7 +201,7 @@ FLAC__bool bitreader_read_from_client_(FLAC__BitReader *br) FLAC__BitReader *FLAC__bitreader_new(void) { - FLAC__BitReader *br = (FLAC__BitReader*)calloc(1, sizeof(FLAC__BitReader)); + FLAC__BitReader *br = calloc(1, sizeof(FLAC__BitReader)); /* calloc() implies: memset(br, 0, sizeof(FLAC__BitReader)); @@ -323,19 +229,18 @@ void FLAC__bitreader_delete(FLAC__BitReader *br) * ***********************************************************************/ -FLAC__bool FLAC__bitreader_init(FLAC__BitReader *br, FLAC__CPUInfo cpu, FLAC__BitReaderReadCallback rcb, void *cd) +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 = (brword*)malloc(sizeof(brword) * br->capacity); + br->buffer = malloc(sizeof(uint32_t) * br->capacity); if(br->buffer == 0) return false; br->read_callback = rcb; br->client_data = cd; - br->cpu_info = cpu; return true; } @@ -410,29 +315,29 @@ FLAC__uint16 FLAC__bitreader_get_read_crc16(FLAC__BitReader *br) /* CRC any tail bytes in a partially-consumed word */ if(br->consumed_bits) { - const brword tail = br->buffer[br->consumed_words]; + const uint32_t tail = br->buffer[br->consumed_words]; for( ; br->crc16_align < br->consumed_bits; br->crc16_align += 8) br->read_crc16 = FLAC__CRC16_UPDATE((unsigned)((tail >> (FLAC__BITS_PER_WORD-8-br->crc16_align)) & 0xff), br->read_crc16); } return br->read_crc16; } -FLaC__INLINE FLAC__bool FLAC__bitreader_is_consumed_byte_aligned(const FLAC__BitReader *br) +inline FLAC__bool FLAC__bitreader_is_consumed_byte_aligned(const FLAC__BitReader *br) { return ((br->consumed_bits & 7) == 0); } -FLaC__INLINE unsigned FLAC__bitreader_bits_left_for_byte_alignment(const FLAC__BitReader *br) +inline unsigned FLAC__bitreader_bits_left_for_byte_alignment(const FLAC__BitReader *br) { return 8 - (br->consumed_bits & 7); } -FLaC__INLINE unsigned FLAC__bitreader_get_input_bits_unconsumed(const FLAC__BitReader *br) +inline unsigned 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__INLINE FLAC__bool FLAC__bitreader_read_raw_uint32(FLAC__BitReader *br, FLAC__uint32 *val, unsigned bits) +FLAC__bool FLAC__bitreader_read_raw_uint32(FLAC__BitReader *br, FLAC__uint32 *val, unsigned bits) { FLAC__ASSERT(0 != br); FLAC__ASSERT(0 != br->buffer); @@ -458,7 +363,7 @@ FLaC__INLINE FLAC__bool FLAC__bitreader_read_raw_uint32(FLAC__BitReader *br, FLA if(br->consumed_bits) { /* 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 - br->consumed_bits; - const brword word = br->buffer[br->consumed_words]; + const uint32_t word = br->buffer[br->consumed_words]; if(bits < n) { *val = (word & (FLAC__WORD_ALL_ONES >> br->consumed_bits)) >> (n-bits); br->consumed_bits += bits; @@ -477,7 +382,7 @@ FLaC__INLINE FLAC__bool FLAC__bitreader_read_raw_uint32(FLAC__BitReader *br, FLA return true; } else { - const brword word = br->buffer[br->consumed_words]; + const uint32_t word = br->buffer[br->consumed_words]; if(bits < FLAC__BITS_PER_WORD) { *val = word >> (FLAC__BITS_PER_WORD-bits); br->consumed_bits = bits; @@ -543,7 +448,7 @@ FLAC__bool FLAC__bitreader_read_raw_uint64(FLAC__BitReader *br, FLAC__uint64 *va return true; } -FLaC__INLINE FLAC__bool FLAC__bitreader_read_uint32_little_endian(FLAC__BitReader *br, FLAC__uint32 *val) +inline FLAC__bool FLAC__bitreader_read_uint32_little_endian(FLAC__BitReader *br, FLAC__uint32 *val) { FLAC__uint32 x8, x32 = 0; @@ -583,7 +488,7 @@ FLAC__bool FLAC__bitreader_skip_bits_no_crc(FLAC__BitReader *br, unsigned bits) FLAC__uint32 x; if(n != 0) { - m = min(8-n, bits); + m = flac_min(8-n, bits); if(!FLAC__bitreader_read_raw_uint32(br, &x, m)) return false; bits -= m; @@ -658,7 +563,7 @@ FLAC__bool FLAC__bitreader_read_byte_block_aligned_no_crc(FLAC__BitReader *br, F /* 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++]; + const uint32_t word = br->buffer[br->consumed_words++]; #if FLAC__BYTES_PER_WORD == 4 val[0] = (FLAC__byte)(word >> 24); val[1] = (FLAC__byte)(word >> 16); @@ -694,7 +599,7 @@ FLAC__bool FLAC__bitreader_read_byte_block_aligned_no_crc(FLAC__BitReader *br, F return true; } -FLaC__INLINE FLAC__bool FLAC__bitreader_read_unary_unsigned(FLAC__BitReader *br, unsigned *val) +FLAC__bool FLAC__bitreader_read_unary_unsigned(FLAC__BitReader *br, unsigned *val) #if 0 /* slow but readable version */ { unsigned bit; @@ -723,9 +628,9 @@ FLaC__INLINE FLAC__bool FLAC__bitreader_read_unary_unsigned(FLAC__BitReader *br, *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; + uint32_t b = br->buffer[br->consumed_words] << br->consumed_bits; if(b) { - i = COUNT_ZERO_MSBS(b); + i = FLAC__clz_uint32(b); *val += i; i++; br->consumed_bits += i; @@ -751,11 +656,11 @@ FLaC__INLINE FLAC__bool FLAC__bitreader_read_unary_unsigned(FLAC__BitReader *br, * us data a byte at a time (unlikely), br->consumed_bits may not * be zero. */ - if(br->bytes) { + if(br->bytes*8 > br->consumed_bits) { const unsigned end = br->bytes * 8; - brword b = (br->buffer[br->consumed_words] & (FLAC__WORD_ALL_ONES << (FLAC__BITS_PER_WORD-end))) << br->consumed_bits; + uint32_t 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); + i = FLAC__clz_uint32(b); *val += i; i++; br->consumed_bits += i; @@ -764,7 +669,7 @@ FLaC__INLINE FLAC__bool FLAC__bitreader_read_unary_unsigned(FLAC__BitReader *br, } else { *val += end - br->consumed_bits; - br->consumed_bits += end; + br->consumed_bits = end; FLAC__ASSERT(br->consumed_bits < FLAC__BITS_PER_WORD); /* didn't find stop bit yet, have to keep going... */ } @@ -803,379 +708,144 @@ FLAC__bool FLAC__bitreader_read_rice_signed(FLAC__BitReader *br, int *val, unsig } /* this is by far the most heavily used reader call. it ain't pretty but it's fast */ -/* a lot of the logic is copied, then adapted, from FLAC__bitreader_read_unary_unsigned() and FLAC__bitreader_read_raw_uint32() */ FLAC__bool FLAC__bitreader_read_rice_signed_block(FLAC__BitReader *br, int vals[], unsigned nvals, unsigned parameter) -/* OPT: possibly faster version for use with MSVC */ -#ifdef _MSC_VER { - unsigned i; - unsigned uval = 0; - unsigned bits; /* the # of binary LSBs left to read to finish a rice codeword */ - /* try and get br->consumed_words and br->consumed_bits into register; * must remember to flush them back to *br before calling other - * bitwriter functions that use them, and before returning */ - register unsigned cwords; - register unsigned cbits; + * bitreader functions that use them, and before returning */ + unsigned cwords, words, lsbs, msbs, x, y; + unsigned ucbits; /* keep track of the number of unconsumed bits in word */ + uint32_t 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 that 2 words, so we don't have to loop to read it */ - - if(nvals == 0) - return true; - - cbits = br->consumed_bits; - cwords = br->consumed_words; + /* 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 */ - while(1) { + val = vals; + end = vals + nvals; - /* read unary part */ - while(1) { - while(cwords < br->words) { /* if we've not consumed up to a partial tail word... */ - brword b = br->buffer[cwords] << cbits; - if(b) { -#if 0 /* slower, probably due to bad register allocation... */ && defined FLAC__CPU_IA32 && !defined FLAC__NO_ASM && FLAC__BITS_PER_WORD == 32 - __asm { - bsr eax, b - not eax - and eax, 31 - mov i, eax - } -#else - i = COUNT_ZERO_MSBS(b); -#endif - uval += i; - bits = parameter; - i++; - cbits += i; - if(cbits == FLAC__BITS_PER_WORD) { - crc16_update_word_(br, br->buffer[cwords]); - cwords++; - cbits = 0; - } - goto break1; - } - else { - uval += FLAC__BITS_PER_WORD - cbits; - crc16_update_word_(br, br->buffer[cwords]); - cwords++; - cbits = 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) { - const unsigned end = br->bytes * 8; - brword b = (br->buffer[cwords] & (FLAC__WORD_ALL_ONES << (FLAC__BITS_PER_WORD-end))) << cbits; - if(b) { - i = COUNT_ZERO_MSBS(b); - uval += i; - bits = parameter; - i++; - cbits += i; - FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD); - goto break1; - } - else { - uval += end - cbits; - cbits += end; - FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD); - /* didn't find stop bit yet, have to keep going... */ - } - } - /* flush registers and read; bitreader_read_from_client_() does - * not touch br->consumed_bits at all but we still need to set - * it in case it fails and we have to return false. - */ - br->consumed_bits = cbits; - br->consumed_words = cwords; - if(!bitreader_read_from_client_(br)) + if(parameter == 0) { + while(val < end) { + /* read the unary MSBs and end bit */ + if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) return false; - cwords = br->consumed_words; - } -break1: - /* read binary part */ - FLAC__ASSERT(cwords <= br->words); - - if(bits) { - while((br->words-cwords)*FLAC__BITS_PER_WORD + br->bytes*8 - cbits < bits) { - /* flush registers and read; bitreader_read_from_client_() does - * not touch br->consumed_bits at all but we still need to set - * it in case it fails and we have to return false. - */ - br->consumed_bits = cbits; - br->consumed_words = cwords; - if(!bitreader_read_from_client_(br)) - return false; - cwords = br->consumed_words; - } - if(cwords < br->words) { /* if we've not consumed up to a partial tail word... */ - if(cbits) { - /* 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]; - if(bits < n) { - uval <<= bits; - uval |= (word & (FLAC__WORD_ALL_ONES >> cbits)) >> (n-bits); - cbits += bits; - goto break2; - } - uval <<= n; - uval |= word & (FLAC__WORD_ALL_ONES >> cbits); - bits -= 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; - } - goto break2; - } - else { - FLAC__ASSERT(bits < FLAC__BITS_PER_WORD); - uval <<= bits; - uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-bits); - cbits = bits; - goto break2; - } - } - 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. - */ - uval <<= bits; - if(cbits) { - /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */ - FLAC__ASSERT(cbits + bits <= br->bytes*8); - uval |= (br->buffer[cwords] & (FLAC__WORD_ALL_ONES >> cbits)) >> (FLAC__BITS_PER_WORD-cbits-bits); - cbits += bits; - goto break2; - } - else { - uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-bits); - cbits += bits; - goto break2; - } - } - } -break2: - /* compose the value */ - *vals = (int)(uval >> 1 ^ -(int)(uval & 1)); - /* are we done? */ - --nvals; - if(nvals == 0) { - br->consumed_bits = cbits; - br->consumed_words = cwords; - return true; + *val++ = (int)(msbs >> 1) ^ -(int)(msbs & 1); } - uval = 0; - ++vals; - + return true; } -} -#else -{ - unsigned i; - unsigned uval = 0; - /* try and get br->consumed_words and br->consumed_bits into register; - * must remember to flush them back to *br before calling other - * bitwriter functions that use them, and before returning */ - register unsigned cwords; - register unsigned cbits; - unsigned ucbits; /* keep track of the number of unconsumed bits in the buffer */ + FLAC__ASSERT(parameter > 0); - 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 */ + cwords = br->consumed_words; + words = br->words; - if(nvals == 0) - return true; + /* if we've not consumed up to a partial tail word... */ + if(cwords >= words) { + x = 0; + goto process_tail; + } - cbits = br->consumed_bits; - cwords = br->consumed_words; - ucbits = (br->words-cwords)*FLAC__BITS_PER_WORD + br->bytes*8 - cbits; + ucbits = FLAC__BITS_PER_WORD - br->consumed_bits; + b = br->buffer[cwords] << br->consumed_bits; /* keep unconsumed bits aligned to left */ - while(1) { + while(val < end) { + /* read the unary MSBs and end bit */ + x = y = FLAC__clz2_uint32(b); + if(x == FLAC__BITS_PER_WORD) { + x = ucbits; + do { + /* didn't find stop bit yet, have to keep going... */ + crc16_update_word_(br, br->buffer[cwords++]); + if (cwords >= words) + goto incomplete_msbs; + b = br->buffer[cwords]; + y = FLAC__clz2_uint32(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 = b >> (FLAC__BITS_PER_WORD - parameter); + if(parameter <= ucbits) { + ucbits -= parameter; + b <<= parameter; + } else { + /* there are still bits left to read, they will all be in the next word */ + crc16_update_word_(br, br->buffer[cwords++]); + if (cwords >= words) + goto incomplete_lsbs; + b = br->buffer[cwords]; + ucbits += FLAC__BITS_PER_WORD - parameter; + x |= b >> ucbits; + b <<= FLAC__BITS_PER_WORD - ucbits; + } + lsbs = x; - /* read unary part */ - while(1) { - while(cwords < br->words) { /* if we've not consumed up to a partial tail word... */ - brword b = br->buffer[cwords] << cbits; - if(b) { -#if 0 /* is not discernably faster... */ && defined FLAC__CPU_IA32 && !defined FLAC__NO_ASM && FLAC__BITS_PER_WORD == 32 && defined __GNUC__ - asm volatile ( - "bsrl %1, %0;" - "notl %0;" - "andl $31, %0;" - : "=r"(i) - : "r"(b) - ); -#else - i = COUNT_ZERO_MSBS(b); -#endif - uval += i; - cbits += i; - cbits++; /* skip over stop bit */ - 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; - } - goto break1; - } - else { - uval += FLAC__BITS_PER_WORD - cbits; - crc16_update_word_(br, br->buffer[cwords]); - cwords++; - cbits = 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) { - const unsigned end = br->bytes * 8; - brword b = (br->buffer[cwords] & ~(FLAC__WORD_ALL_ONES >> end)) << cbits; - if(b) { - i = COUNT_ZERO_MSBS(b); - uval += i; - cbits += i; - cbits++; /* skip over stop bit */ - FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD); - goto break1; - } - else { - uval += end - cbits; - cbits += end; - FLAC__ASSERT(cbits < FLAC__BITS_PER_WORD); - /* didn't find stop bit yet, have to keep going... */ - } + /* 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; } - /* flush registers and read; bitreader_read_from_client_() does - * not touch br->consumed_bits at all but we still need to set - * it in case it fails and we have to return false. - */ - br->consumed_bits = cbits; - br->consumed_words = cwords; - if(!bitreader_read_from_client_(br)) + + /* read the unary MSBs and end bit */ + if(!FLAC__bitreader_read_unary_unsigned(br, &msbs)) return false; - cwords = br->consumed_words; - ucbits = (br->words-cwords)*FLAC__BITS_PER_WORD + br->bytes*8 - cbits + uval; - /* + uval to offset our count by the # of unary bits already - * consumed before the read, because we will add these back - * in all at once at break1 - */ - } -break1: - ucbits -= uval; - ucbits--; /* account for stop bit */ - - /* read binary part */ - FLAC__ASSERT(cwords <= br->words); - - if(parameter) { - while(ucbits < parameter) { - /* flush registers and read; bitreader_read_from_client_() does - * not touch br->consumed_bits at all but we still need to set - * it in case it fails and we have to return false. - */ - br->consumed_bits = cbits; + msbs += x; + x = ucbits = 0; + + if(0) { +incomplete_lsbs: + br->consumed_bits = 0; br->consumed_words = cwords; - if(!bitreader_read_from_client_(br)) - return false; - cwords = br->consumed_words; - ucbits = (br->words-cwords)*FLAC__BITS_PER_WORD + br->bytes*8 - cbits; - } - if(cwords < br->words) { /* if we've not consumed up to a partial tail word... */ - if(cbits) { - /* this also works when consumed_bits==0, it's just slower than necessary for that case */ - const unsigned n = FLAC__BITS_PER_WORD - cbits; - const brword word = br->buffer[cwords]; - if(parameter < n) { - uval <<= parameter; - uval |= (word & (FLAC__WORD_ALL_ONES >> cbits)) >> (n-parameter); - cbits += parameter; - } - else { - uval <<= n; - uval |= word & (FLAC__WORD_ALL_ONES >> cbits); - crc16_update_word_(br, word); - cwords++; - 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)); - } - } - } - else { - cbits = parameter; - uval <<= parameter; - uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-cbits); - } - } - else { - /* in this case we're starting our read at a partial tail word; - * the reader has guaranteed that we have at least 'parameter' - * bits available to read, which makes this case simpler. - */ - uval <<= parameter; - if(cbits) { - /* this also works when consumed_bits==0, it's just a little slower than necessary for that case */ - FLAC__ASSERT(cbits + parameter <= br->bytes*8); - uval |= (br->buffer[cwords] & (FLAC__WORD_ALL_ONES >> cbits)) >> (FLAC__BITS_PER_WORD-cbits-parameter); - cbits += parameter; - } - else { - cbits = parameter; - uval |= br->buffer[cwords] >> (FLAC__BITS_PER_WORD-cbits); - } } - } - ucbits -= parameter; + /* read the binary LSBs */ + if(!FLAC__bitreader_read_raw_uint32(br, &lsbs, parameter - ucbits)) + return false; + lsbs = x | lsbs; - /* compose the value */ - *vals = (int)(uval >> 1 ^ -(int)(uval & 1)); + /* compose the value */ + x = (msbs << parameter) | lsbs; + *val++ = (int)(x >> 1) ^ -(int)(x & 1); + x = 0; - /* are we done? */ - --nvals; - if(nvals == 0) { - br->consumed_bits = cbits; - br->consumed_words = cwords; - return true; - } - - uval = 0; - ++vals; + 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 */ + crc16_update_word_(br, br->buffer[cwords++]); + ucbits = FLAC__BITS_PER_WORD; } + + br->consumed_bits = FLAC__BITS_PER_WORD - ucbits; + br->consumed_words = cwords; + + return true; } -#endif #if 0 /* UNUSED */ FLAC__bool FLAC__bitreader_read_golomb_signed(FLAC__BitReader *br, int *val, unsigned parameter) @@ -1374,3 +1044,16 @@ FLAC__bool FLAC__bitreader_read_utf8_uint64(FLAC__BitReader *br, FLAC__uint64 *v *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 unsigned FLAC__bitreader_bits_left_for_byte_alignment(const FLAC__BitReader *br); +extern unsigned 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); |