X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fbitstream.h;h=996e32e83b91a9b81bdfce82f40e6968212d8590;hb=ea7ee4b4e381e0fa731458de0cbf740430eeb013;hp=fd1b4a94f88694b7bc271f7f9e1a1f5ba32c60ff;hpb=98f7b56bb6562db841219a42ea4e15d43a835c93;p=ffmpeg diff --git a/libavcodec/bitstream.h b/libavcodec/bitstream.h index fd1b4a94f88..996e32e83b9 100644 --- a/libavcodec/bitstream.h +++ b/libavcodec/bitstream.h @@ -1,972 +1,387 @@ /* - * copyright (c) 2004 Michael Niedermayer + * Copyright (c) 2016 Alexandra Hájková * - * This file is part of FFmpeg. + * This file is part of Libav. * - * FFmpeg is free software; you can redistribute it and/or + * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * - * FFmpeg is distributed in the hope that it will be useful, + * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public - * License along with FFmpeg; if not, write to the Free Software + * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** - * @file bitstream.h - * bitstream api header. + * @file + * functions for reading bits from a buffer */ -#ifndef BITSTREAM_H -#define BITSTREAM_H +#ifndef AVCODEC_BITSTREAM_H +#define AVCODEC_BITSTREAM_H #include -#include -#include -#include "common.h" -#include "bswap.h" -#include "log.h" - -#if defined(ALT_BITSTREAM_READER_LE) && !defined(ALT_BITSTREAM_READER) -#define ALT_BITSTREAM_READER -#endif -//#define ALT_BITSTREAM_WRITER -//#define ALIGNED_BITSTREAM_WRITER -#if !defined(LIBMPEG2_BITSTREAM_READER) && !defined(A32_BITSTREAM_READER) && !defined(ALT_BITSTREAM_READER) -# ifdef ARCH_ARMV4L -# define A32_BITSTREAM_READER -# else -#define ALT_BITSTREAM_READER -//#define LIBMPEG2_BITSTREAM_READER -//#define A32_BITSTREAM_READER -# endif -#endif -#define LIBMPEG2_BITSTREAM_READER_HACK //add BERO - -extern const uint8_t ff_reverse[256]; - -#if defined(ARCH_X86) -// avoid +32 for shift optimization (gcc should do that ...) -static inline int32_t NEG_SSR32( int32_t a, int8_t s){ - asm ("sarl %1, %0\n\t" - : "+r" (a) - : "ic" ((uint8_t)(-s)) - ); - return a; -} -static inline uint32_t NEG_USR32(uint32_t a, int8_t s){ - asm ("shrl %1, %0\n\t" - : "+r" (a) - : "ic" ((uint8_t)(-s)) - ); - return a; -} -#else -# define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s))) -# define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s))) -#endif +#include "libavutil/common.h" +#include "libavutil/intreadwrite.h" +#include "libavutil/log.h" -/* bit output */ +#include "mathops.h" +#include "vlc.h" -/* buf and buf_end must be present and used by every alternative writer. */ -typedef struct PutBitContext { -#ifdef ALT_BITSTREAM_WRITER - uint8_t *buf, *buf_end; - int index; -#else - uint32_t bit_buf; - int bit_left; - uint8_t *buf, *buf_ptr, *buf_end; -#endif -} PutBitContext; +typedef struct BitstreamContext { + uint64_t bits; // stores bits read from the buffer + const uint8_t *buffer, *buffer_end; + const uint8_t *ptr; // position inside a buffer + unsigned bits_left; // number of bits left in bits field + unsigned size_in_bits; +} BitstreamContext; -static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size) +static inline void refill_64(BitstreamContext *bc) { - if(buffer_size < 0) { - buffer_size = 0; - buffer = NULL; - } + if (bc->ptr >= bc->buffer_end) + return; - s->buf = buffer; - s->buf_end = s->buf + buffer_size; -#ifdef ALT_BITSTREAM_WRITER - s->index=0; - ((uint32_t*)(s->buf))[0]=0; -// memset(buffer, 0, buffer_size); +#ifdef BITSTREAM_READER_LE + bc->bits = AV_RL64(bc->ptr); #else - s->buf_ptr = s->buf; - s->bit_left=32; - s->bit_buf=0; + bc->bits = AV_RB64(bc->ptr); #endif + bc->ptr += 8; + bc->bits_left = 64; } -/* return the number of bits output */ -static inline int put_bits_count(PutBitContext *s) +static inline void refill_32(BitstreamContext *bc) { -#ifdef ALT_BITSTREAM_WRITER - return s->index; + if (bc->ptr >= bc->buffer_end) + return; + +#ifdef BITSTREAM_READER_LE + bc->bits = (uint64_t)AV_RL32(bc->ptr) << bc->bits_left | bc->bits; #else - return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left; + bc->bits = bc->bits | (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_left); #endif + bc->ptr += 4; + bc->bits_left += 32; } -/* pad the end of the output stream with zeros */ -static inline void flush_put_bits(PutBitContext *s) +/* Initialize BitstreamContext. Input buffer must have an additional zero + * padding of AV_INPUT_BUFFER_PADDING_SIZE bytes at the end. */ +static inline int bitstream_init(BitstreamContext *bc, const uint8_t *buffer, + unsigned bit_size) { -#ifdef ALT_BITSTREAM_WRITER - align_put_bits(s); -#else - s->bit_buf<<= s->bit_left; - while (s->bit_left < 32) { - /* XXX: should test end of buffer */ - *s->buf_ptr++=s->bit_buf >> 24; - s->bit_buf<<=8; - s->bit_left+=8; + unsigned buffer_size; + + if (bit_size > INT_MAX - 7 || !buffer) { + buffer = + bc->buffer = + bc->ptr = NULL; + bc->bits_left = 0; + return AVERROR_INVALIDDATA; } - s->bit_left=32; - s->bit_buf=0; -#endif -} - -void align_put_bits(PutBitContext *s); -void ff_put_string(PutBitContext * pbc, char *s, int put_zero); -void ff_copy_bits(PutBitContext *pb, uint8_t *src, int length); - -/* bit input */ -/* buffer, buffer_end and size_in_bits must be present and used by every reader */ -typedef struct GetBitContext { - const uint8_t *buffer, *buffer_end; -#ifdef ALT_BITSTREAM_READER - int index; -#elif defined LIBMPEG2_BITSTREAM_READER - uint8_t *buffer_ptr; - uint32_t cache; - int bit_count; -#elif defined A32_BITSTREAM_READER - uint32_t *buffer_ptr; - uint32_t cache0; - uint32_t cache1; - int bit_count; -#endif - int size_in_bits; -} GetBitContext; -#define VLC_TYPE int16_t + buffer_size = (bit_size + 7) >> 3; -typedef struct VLC { - int bits; - VLC_TYPE (*table)[2]; ///< code, bits - int table_size, table_allocated; -} VLC; + bc->buffer = buffer; + bc->buffer_end = buffer + buffer_size; + bc->ptr = bc->buffer; + bc->size_in_bits = bit_size; + bc->bits_left = 0; + bc->bits = 0; -typedef struct RL_VLC_ELEM { - int16_t level; - int8_t len; - uint8_t run; -} RL_VLC_ELEM; + refill_64(bc); -#if defined(ARCH_SPARC) || defined(ARCH_ARMV4L) || defined(ARCH_MIPS) || defined(ARCH_BFIN) -#define UNALIGNED_STORES_ARE_BAD -#endif - -/* used to avoid missaligned exceptions on some archs (alpha, ...) */ -#if defined(ARCH_X86) -# define unaligned16(a) (*(const uint16_t*)(a)) -# define unaligned32(a) (*(const uint32_t*)(a)) -# define unaligned64(a) (*(const uint64_t*)(a)) -#else -# ifdef __GNUC__ -# define unaligned(x) \ -static inline uint##x##_t unaligned##x(const void *v) { \ - struct Unaligned { \ - uint##x##_t i; \ - } __attribute__((packed)); \ - \ - return ((const struct Unaligned *) v)->i; \ -} -# elif defined(__DECC) -# define unaligned(x) \ -static inline uint##x##_t unaligned##x(const void *v) { \ - return *(const __unaligned uint##x##_t *) v; \ -} -# else -# define unaligned(x) \ -static inline uint##x##_t unaligned##x(const void *v) { \ - return *(const uint##x##_t *) v; \ + return 0; } -# endif -unaligned(16) -unaligned(32) -unaligned(64) -#undef unaligned -#endif /* defined(ARCH_X86) */ - -#ifndef ALT_BITSTREAM_WRITER -static inline void put_bits(PutBitContext *s, int n, unsigned int value) -{ - unsigned int bit_buf; - int bit_left; - - // printf("put_bits=%d %x\n", n, value); - assert(n == 32 || value < (1U << n)); - - bit_buf = s->bit_buf; - bit_left = s->bit_left; - - // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf); - /* XXX: optimize */ - if (n < bit_left) { - bit_buf = (bit_buf<> (n - bit_left); -#ifdef UNALIGNED_STORES_ARE_BAD - if (3 & (intptr_t) s->buf_ptr) { - s->buf_ptr[0] = bit_buf >> 24; - s->buf_ptr[1] = bit_buf >> 16; - s->buf_ptr[2] = bit_buf >> 8; - s->buf_ptr[3] = bit_buf ; - } else -#endif - *(uint32_t *)s->buf_ptr = be2me_32(bit_buf); - //printf("bitbuf = %08x\n", bit_buf); - s->buf_ptr+=4; - bit_left+=32 - n; - bit_buf = value; - } - s->bit_buf = bit_buf; - s->bit_left = bit_left; +/* Initialize BitstreamContext with buffer size in bytes instead of bits. */ +static inline int bitstream_init8(BitstreamContext *bc, const uint8_t *buffer, + unsigned byte_size) +{ + if (byte_size > INT_MAX / 8) + return AVERROR_INVALIDDATA; + return bitstream_init(bc, buffer, byte_size * 8); } -#endif - -#ifdef ALT_BITSTREAM_WRITER -static inline void put_bits(PutBitContext *s, int n, unsigned int value) +/* Return number of bits already read. */ +static inline int bitstream_tell(const BitstreamContext *bc) { -# ifdef ALIGNED_BITSTREAM_WRITER -# if defined(ARCH_X86) - asm volatile( - "movl %0, %%ecx \n\t" - "xorl %%eax, %%eax \n\t" - "shrdl %%cl, %1, %%eax \n\t" - "shrl %%cl, %1 \n\t" - "movl %0, %%ecx \n\t" - "shrl $3, %%ecx \n\t" - "andl $0xFFFFFFFC, %%ecx \n\t" - "bswapl %1 \n\t" - "orl %1, (%2, %%ecx) \n\t" - "bswapl %%eax \n\t" - "addl %3, %0 \n\t" - "movl %%eax, 4(%2, %%ecx) \n\t" - : "=&r" (s->index), "=&r" (value) - : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n)) - : "%eax", "%ecx" - ); -# else - int index= s->index; - uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5); - - value<<= 32-n; - - ptr[0] |= be2me_32(value>>(index&31)); - ptr[1] = be2me_32(value<<(32-(index&31))); -//if(n>24) printf("%d %d\n", n, value); - index+= n; - s->index= index; -# endif -# else //ALIGNED_BITSTREAM_WRITER -# if defined(ARCH_X86) - asm volatile( - "movl $7, %%ecx \n\t" - "andl %0, %%ecx \n\t" - "addl %3, %%ecx \n\t" - "negl %%ecx \n\t" - "shll %%cl, %1 \n\t" - "bswapl %1 \n\t" - "movl %0, %%ecx \n\t" - "shrl $3, %%ecx \n\t" - "orl %1, (%%ecx, %2) \n\t" - "addl %3, %0 \n\t" - "movl $0, 4(%%ecx, %2) \n\t" - : "=&r" (s->index), "=&r" (value) - : "r" (s->buf), "r" (n), "0" (s->index), "1" (value) - : "%ecx" - ); -# else - int index= s->index; - uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3)); - - ptr[0] |= be2me_32(value<<(32-n-(index&7) )); - ptr[1] = 0; -//if(n>24) printf("%d %d\n", n, value); - index+= n; - s->index= index; -# endif -# endif //!ALIGNED_BITSTREAM_WRITER + return (bc->ptr - bc->buffer) * 8 - bc->bits_left; } -#endif - -static inline uint8_t* pbBufPtr(PutBitContext *s) +/* Return buffer size in bits. */ +static inline int bitstream_tell_size(const BitstreamContext *bc) { -#ifdef ALT_BITSTREAM_WRITER - return s->buf + (s->index>>3); -#else - return s->buf_ptr; -#endif + return bc->size_in_bits; } -/** - * - * PutBitContext must be flushed & aligned to a byte boundary before calling this. - */ -static inline void skip_put_bytes(PutBitContext *s, int n){ - assert((put_bits_count(s)&7)==0); -#ifdef ALT_BITSTREAM_WRITER - FIXME may need some cleaning of the buffer - s->index += n<<3; -#else - assert(s->bit_left==32); - s->buf_ptr += n; -#endif +/* Return the number of the bits left in a buffer. */ +static inline int bitstream_bits_left(const BitstreamContext *bc) +{ + return (bc->buffer - bc->ptr) * 8 + bc->size_in_bits + bc->bits_left; } -/** - * Skips the given number of bits. - * Must only be used if the actual values in the bitstream do not matter. - */ -static inline void skip_put_bits(PutBitContext *s, int n){ -#ifdef ALT_BITSTREAM_WRITER - s->index += n; +static inline uint64_t get_val(BitstreamContext *bc, unsigned n) +{ +#ifdef BITSTREAM_READER_LE + uint64_t ret = bc->bits & ((UINT64_C(1) << n) - 1); + bc->bits >>= n; #else - s->bit_left -= n; - s->buf_ptr-= s->bit_left>>5; - s->bit_left &= 31; + uint64_t ret = bc->bits >> (64 - n); + bc->bits <<= n; #endif -} + bc->bits_left -= n; -/** - * Changes the end of the buffer. - */ -static inline void set_put_bits_buffer_size(PutBitContext *s, int size){ - s->buf_end= s->buf + size; + return ret; } -/* Bitstream reader API docs: -name - abritary name which is used as prefix for the internal variables - -gb - getbitcontext - -OPEN_READER(name, gb) - loads gb into local variables - -CLOSE_READER(name, gb) - stores local vars in gb - -UPDATE_CACHE(name, gb) - refills the internal cache from the bitstream - after this call at least MIN_CACHE_BITS will be available, - -GET_CACHE(name, gb) - will output the contents of the internal cache, next bit is MSB of 32 or 64 bit (FIXME 64bit) - -SHOW_UBITS(name, gb, num) - will return the next num bits - -SHOW_SBITS(name, gb, num) - will return the next num bits and do sign extension - -SKIP_BITS(name, gb, num) - will skip over the next num bits - note, this is equivalent to SKIP_CACHE; SKIP_COUNTER - -SKIP_CACHE(name, gb, num) - will remove the next num bits from the cache (note SKIP_COUNTER MUST be called before UPDATE_CACHE / CLOSE_READER) - -SKIP_COUNTER(name, gb, num) - will increment the internal bit counter (see SKIP_CACHE & SKIP_BITS) - -LAST_SKIP_CACHE(name, gb, num) - will remove the next num bits from the cache if it is needed for UPDATE_CACHE otherwise it will do nothing - -LAST_SKIP_BITS(name, gb, num) - is equivalent to SKIP_LAST_CACHE; SKIP_COUNTER - -for examples see get_bits, show_bits, skip_bits, get_vlc -*/ - -static inline int unaligned32_be(const void *v) +/* Return one bit from the buffer. */ +static inline unsigned bitstream_read_bit(BitstreamContext *bc) { -#ifdef CONFIG_ALIGN - const uint8_t *p=v; - return (((p[0]<<8) | p[1])<<16) | (p[2]<<8) | (p[3]); -#else - return be2me_32( unaligned32(v)); //original -#endif + if (!bc->bits_left) + refill_64(bc); + + return get_val(bc, 1); } -static inline int unaligned32_le(const void *v) +/* Return n bits from the buffer. n has to be in the 0-63 range. */ +static inline uint64_t bitstream_read_63(BitstreamContext *bc, unsigned n) { -#ifdef CONFIG_ALIGN - const uint8_t *p=v; - return (((p[3]<<8) | p[2])<<16) | (p[1]<<8) | (p[0]); -#else - return le2me_32( unaligned32(v)); //original + uint64_t ret = 0; +#ifdef BITSTREAM_READER_LE + uint64_t left = 0; #endif -} - -#ifdef ALT_BITSTREAM_READER -# define MIN_CACHE_BITS 25 - -# define OPEN_READER(name, gb)\ - int name##_index= (gb)->index;\ - int name##_cache= 0;\ - -# define CLOSE_READER(name, gb)\ - (gb)->index= name##_index;\ - -# ifdef ALT_BITSTREAM_READER_LE -# define UPDATE_CACHE(name, gb)\ - name##_cache= unaligned32_le( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\ - -# define SKIP_CACHE(name, gb, num)\ - name##_cache >>= (num); -# else -# define UPDATE_CACHE(name, gb)\ - name##_cache= unaligned32_be( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\ - -# define SKIP_CACHE(name, gb, num)\ - name##_cache <<= (num); -# endif - -// FIXME name? -# define SKIP_COUNTER(name, gb, num)\ - name##_index += (num);\ - -# define SKIP_BITS(name, gb, num)\ - {\ - SKIP_CACHE(name, gb, num)\ - SKIP_COUNTER(name, gb, num)\ - }\ - -# define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num) -# define LAST_SKIP_CACHE(name, gb, num) ; - -# ifdef ALT_BITSTREAM_READER_LE -# define SHOW_UBITS(name, gb, num)\ - ((name##_cache) & (NEG_USR32(0xffffffff,num))) - -# define SHOW_SBITS(name, gb, num)\ - NEG_SSR32((name##_cache)<<(32-(num)), num) -# else -# define SHOW_UBITS(name, gb, num)\ - NEG_USR32(name##_cache, num) - -# define SHOW_SBITS(name, gb, num)\ - NEG_SSR32(name##_cache, num) -# endif - -# define GET_CACHE(name, gb)\ - ((uint32_t)name##_cache) - -static inline int get_bits_count(GetBitContext *s){ - return s->index; -} - -static inline void skip_bits_long(GetBitContext *s, int n){ - s->index += n; -} - -#elif defined LIBMPEG2_BITSTREAM_READER -//libmpeg2 like reader - -# define MIN_CACHE_BITS 17 - -# define OPEN_READER(name, gb)\ - int name##_bit_count=(gb)->bit_count;\ - int name##_cache= (gb)->cache;\ - uint8_t * name##_buffer_ptr=(gb)->buffer_ptr;\ - -# define CLOSE_READER(name, gb)\ - (gb)->bit_count= name##_bit_count;\ - (gb)->cache= name##_cache;\ - (gb)->buffer_ptr= name##_buffer_ptr;\ - -#ifdef LIBMPEG2_BITSTREAM_READER_HACK - -# define UPDATE_CACHE(name, gb)\ - if(name##_bit_count >= 0){\ - name##_cache+= (int)be2me_16(*(uint16_t*)name##_buffer_ptr) << name##_bit_count;\ - name##_buffer_ptr += 2;\ - name##_bit_count-= 16;\ - }\ - -#else -# define UPDATE_CACHE(name, gb)\ - if(name##_bit_count >= 0){\ - name##_cache+= ((name##_buffer_ptr[0]<<8) + name##_buffer_ptr[1]) << name##_bit_count;\ - name##_buffer_ptr+=2;\ - name##_bit_count-= 16;\ - }\ + if (!n) + return 0; + if (n > bc->bits_left) { + n -= bc->bits_left; +#ifdef BITSTREAM_READER_LE + left = bc->bits_left; #endif + ret = get_val(bc, bc->bits_left); + refill_64(bc); + } -# define SKIP_CACHE(name, gb, num)\ - name##_cache <<= (num);\ - -# define SKIP_COUNTER(name, gb, num)\ - name##_bit_count += (num);\ - -# define SKIP_BITS(name, gb, num)\ - {\ - SKIP_CACHE(name, gb, num)\ - SKIP_COUNTER(name, gb, num)\ - }\ - -# define LAST_SKIP_BITS(name, gb, num) SKIP_BITS(name, gb, num) -# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num) - -# define SHOW_UBITS(name, gb, num)\ - NEG_USR32(name##_cache, num) - -# define SHOW_SBITS(name, gb, num)\ - NEG_SSR32(name##_cache, num) - -# define GET_CACHE(name, gb)\ - ((uint32_t)name##_cache) - -static inline int get_bits_count(GetBitContext *s){ - return (s->buffer_ptr - s->buffer)*8 - 16 + s->bit_count; -} - -static inline void skip_bits_long(GetBitContext *s, int n){ - OPEN_READER(re, s) - re_bit_count += n; - re_buffer_ptr += 2*(re_bit_count>>4); - re_bit_count &= 15; - re_cache = ((re_buffer_ptr[-2]<<8) + re_buffer_ptr[-1]) << (16+re_bit_count); - UPDATE_CACHE(re, s) - CLOSE_READER(re, s) -} - -#elif defined A32_BITSTREAM_READER - -# define MIN_CACHE_BITS 32 - -# define OPEN_READER(name, gb)\ - int name##_bit_count=(gb)->bit_count;\ - uint32_t name##_cache0= (gb)->cache0;\ - uint32_t name##_cache1= (gb)->cache1;\ - uint32_t * name##_buffer_ptr=(gb)->buffer_ptr;\ - -# define CLOSE_READER(name, gb)\ - (gb)->bit_count= name##_bit_count;\ - (gb)->cache0= name##_cache0;\ - (gb)->cache1= name##_cache1;\ - (gb)->buffer_ptr= name##_buffer_ptr;\ - -# define UPDATE_CACHE(name, gb)\ - if(name##_bit_count > 0){\ - const uint32_t next= be2me_32( *name##_buffer_ptr );\ - name##_cache0 |= NEG_USR32(next,name##_bit_count);\ - name##_cache1 |= next<buffer_ptr - s->buffer)*8 - 32 + s->bit_count; -} - -static inline void skip_bits_long(GetBitContext *s, int n){ - OPEN_READER(re, s) - re_bit_count += n; - re_buffer_ptr += re_bit_count>>5; - re_bit_count &= 31; - re_cache0 = be2me_32( re_buffer_ptr[-1] ) << re_bit_count; - re_cache1 = 0; - UPDATE_CACHE(re, s) - CLOSE_READER(re, s) + return ret; } -#endif - -/** - * read mpeg1 dc style vlc (sign bit + mantisse with no MSB). - * if MSB not set it is negative - * @param n length in bits - * @author BERO - */ -static inline int get_xbits(GetBitContext *s, int n){ - register int sign; - register int32_t cache; - OPEN_READER(re, s) - UPDATE_CACHE(re, s) - cache = GET_CACHE(re,s); - sign=(~cache)>>31; - LAST_SKIP_BITS(re, s, n) - CLOSE_READER(re, s) - return (NEG_USR32(sign ^ cache, n) ^ sign) - sign; -} - -static inline int get_sbits(GetBitContext *s, int n){ - register int tmp; - OPEN_READER(re, s) - UPDATE_CACHE(re, s) - tmp= SHOW_SBITS(re, s, n); - LAST_SKIP_BITS(re, s, n) - CLOSE_READER(re, s) - return tmp; -} +/* Return n bits from the buffer. n has to be in the 0-32 range. */ +static inline uint32_t bitstream_read(BitstreamContext *bc, unsigned n) +{ + if (!n) + return 0; -/** - * reads 1-17 bits. - * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't - */ -static inline unsigned int get_bits(GetBitContext *s, int n){ - register int tmp; - OPEN_READER(re, s) - UPDATE_CACHE(re, s) - tmp= SHOW_UBITS(re, s, n); - LAST_SKIP_BITS(re, s, n) - CLOSE_READER(re, s) - return tmp; -} + if (n > bc->bits_left) { + refill_32(bc); + if (bc->bits_left < 32) + bc->bits_left = n; + } -/** - * shows 1-17 bits. - * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't - */ -static inline unsigned int show_bits(GetBitContext *s, int n){ - register int tmp; - OPEN_READER(re, s) - UPDATE_CACHE(re, s) - tmp= SHOW_UBITS(re, s, n); -// CLOSE_READER(re, s) - return tmp; + return get_val(bc, n); } -static inline void skip_bits(GetBitContext *s, int n){ - //Note gcc seems to optimize this to s->index+=n for the ALT_READER :)) - OPEN_READER(re, s) - UPDATE_CACHE(re, s) - LAST_SKIP_BITS(re, s, n) - CLOSE_READER(re, s) +/* Return n bits from the buffer as a signed integer. + * n has to be in the 0-32 range. */ +static inline int32_t bitstream_read_signed(BitstreamContext *bc, unsigned n) +{ + return sign_extend(bitstream_read(bc, n), n); } -static inline unsigned int get_bits1(GetBitContext *s){ -#ifdef ALT_BITSTREAM_READER - int index= s->index; - uint8_t result= s->buffer[ index>>3 ]; -#ifdef ALT_BITSTREAM_READER_LE - result>>= (index&0x07); - result&= 1; -#else - result<<= (index&0x07); - result>>= 8 - 1; -#endif - index++; - s->index= index; - - return result; +static inline unsigned show_val(const BitstreamContext *bc, unsigned n) +{ +#ifdef BITSTREAM_READER_LE + return bc->bits & ((UINT64_C(1) << n) - 1); #else - return get_bits(s, 1); + return bc->bits >> (64 - n); #endif } -static inline unsigned int show_bits1(GetBitContext *s){ - return show_bits(s, 1); +/* Return n bits from the buffer, but do not change the buffer state. + * n has to be in the 0-32 range. */ +static inline unsigned bitstream_peek(BitstreamContext *bc, unsigned n) +{ + if (n > bc->bits_left) + refill_32(bc); + + return show_val(bc, n); } -static inline void skip_bits1(GetBitContext *s){ - skip_bits(s, 1); +/* Return n bits from the buffer as a signed integer, but do not change the + * buffer state. n has to be in the 0-32 range. */ +static inline int bitstream_peek_signed(BitstreamContext *bc, unsigned n) +{ + return sign_extend(bitstream_peek(bc, n), n); } -/** - * reads 0-32 bits. - */ -static inline unsigned int get_bits_long(GetBitContext *s, int n){ - if(n<=17) return get_bits(s, n); - else{ -#ifdef ALT_BITSTREAM_READER_LE - int ret= get_bits(s, 16); - return ret | (get_bits(s, n-16) << 16); +static inline void skip_remaining(BitstreamContext *bc, unsigned n) +{ +#ifdef BITSTREAM_READER_LE + bc->bits >>= n; #else - int ret= get_bits(s, 16) << (n-16); - return ret | get_bits(s, n-16); + bc->bits <<= n; #endif - } + bc->bits_left -= n; } -/** - * shows 0-32 bits. - */ -static inline unsigned int show_bits_long(GetBitContext *s, int n){ - if(n<=17) return show_bits(s, n); - else{ - GetBitContext gb= *s; - int ret= get_bits_long(s, n); - *s= gb; - return ret; +/* Skip n bits in the buffer. */ +static inline void bitstream_skip(BitstreamContext *bc, unsigned n) +{ + if (n <= bc->bits_left) + skip_remaining(bc, n); + else { + n -= bc->bits_left; + skip_remaining(bc, bc->bits_left); + if (n >= 64) { + unsigned skip = n / 8; + + n -= skip * 8; + bc->ptr += skip; + } + refill_64(bc); + if (n) + skip_remaining(bc, n); } } -static inline int check_marker(GetBitContext *s, const char *msg) +/* Seek to the given bit position. */ +static inline void bitstream_seek(BitstreamContext *bc, unsigned pos) { - int bit= get_bits1(s); - if(!bit) - av_log(NULL, AV_LOG_INFO, "Marker bit missing %s\n", msg); + bc->ptr = bc->buffer; + bc->bits = 0; + bc->bits_left = 0; - return bit; + bitstream_skip(bc, pos); } -/** - * init GetBitContext. - * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits - * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end - * @param bit_size the size of the buffer in bits - */ -static inline void init_get_bits(GetBitContext *s, - const uint8_t *buffer, int bit_size) +/* Skip bits to a byte boundary. */ +static inline const uint8_t *bitstream_align(BitstreamContext *bc) { - int buffer_size= (bit_size+7)>>3; - if(buffer_size < 0 || bit_size < 0) { - buffer_size = bit_size = 0; - buffer = NULL; - } - - s->buffer= buffer; - s->size_in_bits= bit_size; - s->buffer_end= buffer + buffer_size; -#ifdef ALT_BITSTREAM_READER - s->index=0; -#elif defined LIBMPEG2_BITSTREAM_READER - s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1)); - s->bit_count = 16 + 8*((intptr_t)buffer&1); - skip_bits_long(s, 0); -#elif defined A32_BITSTREAM_READER - s->buffer_ptr = (uint32_t*)((intptr_t)buffer&(~3)); - s->bit_count = 32 + 8*((intptr_t)buffer&3); - skip_bits_long(s, 0); -#endif + unsigned n = -bitstream_tell(bc) & 7; + if (n) + bitstream_skip(bc, n); + return bc->buffer + (bitstream_tell(bc) >> 3); } -static inline void align_get_bits(GetBitContext *s) +/* Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB). + * If MSB not set it is negative. */ +static inline int bitstream_read_xbits(BitstreamContext *bc, unsigned length) { - int n= (-get_bits_count(s)) & 7; - if(n) skip_bits(s, n); + int32_t cache = bitstream_peek(bc, 32); + int sign = ~cache >> 31; + skip_remaining(bc, length); + + return ((((uint32_t)(sign ^ cache)) >> (32 - length)) ^ sign) - sign; } -#define init_vlc(vlc, nb_bits, nb_codes,\ - bits, bits_wrap, bits_size,\ - codes, codes_wrap, codes_size,\ - flags)\ - init_vlc_sparse(vlc, nb_bits, nb_codes,\ - bits, bits_wrap, bits_size,\ - codes, codes_wrap, codes_size,\ - NULL, 0, 0, flags) - -int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, - const void *bits, int bits_wrap, int bits_size, - const void *codes, int codes_wrap, int codes_size, - const void *symbols, int symbols_wrap, int symbols_size, - int flags); -#define INIT_VLC_USE_STATIC 1 -#define INIT_VLC_LE 2 -void free_vlc(VLC *vlc); +/* Return the LUT element for the given bitstream configuration. */ +static inline int set_idx(BitstreamContext *bc, int code, int *n, int *nb_bits, + VLC_TYPE (*table)[2]) +{ + unsigned idx; -/** - * - * if the vlc code is invalid and max_depth=1 than no bits will be removed - * if the vlc code is invalid and max_depth>1 than the number of bits removed - * is undefined - */ -#define GET_VLC(code, name, gb, table, bits, max_depth)\ -{\ - int n, index, nb_bits;\ -\ - index= SHOW_UBITS(name, gb, bits);\ - code = table[index][0];\ - n = table[index][1];\ -\ - if(max_depth > 1 && n < 0){\ - LAST_SKIP_BITS(name, gb, bits)\ - UPDATE_CACHE(name, gb)\ -\ - nb_bits = -n;\ -\ - index= SHOW_UBITS(name, gb, nb_bits) + code;\ - code = table[index][0];\ - n = table[index][1];\ - if(max_depth > 2 && n < 0){\ - LAST_SKIP_BITS(name, gb, nb_bits)\ - UPDATE_CACHE(name, gb)\ -\ - nb_bits = -n;\ -\ - index= SHOW_UBITS(name, gb, nb_bits) + code;\ - code = table[index][0];\ - n = table[index][1];\ - }\ - }\ - SKIP_BITS(name, gb, n)\ -} + *nb_bits = -*n; + idx = bitstream_peek(bc, *nb_bits) + code; + *n = table[idx][1]; -#define GET_RL_VLC(level, run, name, gb, table, bits, max_depth, need_update)\ -{\ - int n, index, nb_bits;\ -\ - index= SHOW_UBITS(name, gb, bits);\ - level = table[index].level;\ - n = table[index].len;\ -\ - if(max_depth > 1 && n < 0){\ - SKIP_BITS(name, gb, bits)\ - if(need_update){\ - UPDATE_CACHE(name, gb)\ - }\ -\ - nb_bits = -n;\ -\ - index= SHOW_UBITS(name, gb, nb_bits) + level;\ - level = table[index].level;\ - n = table[index].len;\ - }\ - run= table[index].run;\ - SKIP_BITS(name, gb, n)\ + return table[idx][0]; } - /** - * parses a vlc code, faster then get_vlc() - * @param bits is the number of bits which will be read at once, must be - * identical to nb_bits in init_vlc() + * Parse a VLC code. + * @param bits is the number of bits which will be read at once, must be + * identical to nb_bits in init_vlc() * @param max_depth is the number of times bits bits must be read to completely - * read the longest vlc code + * read the longest VLC code * = (max_vlc_length + bits - 1) / bits - */ -static av_always_inline int get_vlc2(GetBitContext *s, VLC_TYPE (*table)[2], - int bits, int max_depth) + * If the VLC code is invalid and max_depth = 1, then no bits will be removed. + * If the VLC code is invalid and max_depth > 1, then the number of bits removed + * is undefined. */ +static inline int bitstream_read_vlc(BitstreamContext *bc, VLC_TYPE (*table)[2], + int bits, int max_depth) { - int code; - - OPEN_READER(re, s) - UPDATE_CACHE(re, s) - - GET_VLC(code, re, s, table, bits, max_depth) - - CLOSE_READER(re, s) - return code; -} - -//#define TRACE - -#ifdef TRACE -static inline void print_bin(int bits, int n){ - int i; - - for(i=n-1; i>=0; i--){ - av_log(NULL, AV_LOG_DEBUG, "%d", (bits>>i)&1); + int nb_bits; + unsigned idx = bitstream_peek(bc, bits); + int code = table[idx][0]; + int n = table[idx][1]; + + if (max_depth > 1 && n < 0) { + skip_remaining(bc, bits); + code = set_idx(bc, code, &n, &nb_bits, table); + if (max_depth > 2 && n < 0) { + skip_remaining(bc, nb_bits); + code = set_idx(bc, code, &n, &nb_bits, table); + } } - for(i=n; i<24; i++) - av_log(NULL, AV_LOG_DEBUG, " "); -} + skip_remaining(bc, n); -static inline int get_bits_trace(GetBitContext *s, int n, char *file, const char *func, int line){ - int r= get_bits(s, n); - - print_bin(r, n); - av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d bit @%5d in %s %s:%d\n", r, n, r, get_bits_count(s)-n, file, func, line); - return r; -} -static inline int get_vlc_trace(GetBitContext *s, VLC_TYPE (*table)[2], int bits, int max_depth, char *file, const char *func, int line){ - int show= show_bits(s, 24); - int pos= get_bits_count(s); - int r= get_vlc2(s, table, bits, max_depth); - int len= get_bits_count(s) - pos; - int bits2= show>>(24-len); - - print_bin(bits2, len); - - av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d vlc @%5d in %s %s:%d\n", bits2, len, r, pos, file, func, line); - return r; + return code; } -static inline int get_xbits_trace(GetBitContext *s, int n, char *file, const char *func, int line){ - int show= show_bits(s, n); - int r= get_xbits(s, n); - print_bin(show, n); - av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d xbt @%5d in %s %s:%d\n", show, n, r, get_bits_count(s)-n, file, func, line); - return r; +#define BITSTREAM_RL_VLC(level, run, bc, table, bits, max_depth) \ + do { \ + int n, nb_bits; \ + unsigned index = bitstream_peek(bc, bits); \ + level = table[index].level; \ + n = table[index].len; \ + \ + if (max_depth > 1 && n < 0) { \ + bitstream_skip(bc, bits); \ + \ + nb_bits = -n; \ + \ + index = bitstream_peek(bc, nb_bits) + level; \ + level = table[index].level; \ + n = table[index].len; \ + if (max_depth > 2 && n < 0) { \ + bitstream_skip(bc, nb_bits); \ + nb_bits = -n; \ + \ + index = bitstream_peek(bc, nb_bits) + level; \ + level = table[index].level; \ + n = table[index].len; \ + } \ + } \ + run = table[index].run; \ + bitstream_skip(bc, n); \ + } while (0) + +/* Return decoded truncated unary code for the values 0, 1, 2. */ +static inline int bitstream_decode012(BitstreamContext *bc) +{ + if (!bitstream_read_bit(bc)) + return 0; + else + return bitstream_read_bit(bc) + 1; } -#define get_bits(s, n) get_bits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__) -#define get_bits1(s) get_bits_trace(s, 1, __FILE__, __PRETTY_FUNCTION__, __LINE__) -#define get_xbits(s, n) get_xbits_trace(s, n, __FILE__, __PRETTY_FUNCTION__, __LINE__) -#define get_vlc(s, vlc) get_vlc_trace(s, (vlc)->table, (vlc)->bits, 3, __FILE__, __PRETTY_FUNCTION__, __LINE__) -#define get_vlc2(s, tab, bits, max) get_vlc_trace(s, tab, bits, max, __FILE__, __PRETTY_FUNCTION__, __LINE__) - -#define tprintf(p, ...) av_log(p, AV_LOG_DEBUG, __VA_ARGS__) - -#else //TRACE -#define tprintf(p, ...) {} -#endif - -static inline int decode012(GetBitContext *gb){ - int n; - n = get_bits1(gb); - if (n == 0) +/* Return decoded truncated unary code for the values 2, 1, 0. */ +static inline int bitstream_decode210(BitstreamContext *bc) +{ + if (bitstream_read_bit(bc)) return 0; else - return get_bits1(gb) + 1; + return 2 - bitstream_read_bit(bc); +} + +/* Read sign bit and flip the sign of the provided value accordingly. */ +static inline int bitstream_apply_sign(BitstreamContext *bc, int val) +{ + int sign = bitstream_read_signed(bc, 1); + return (val ^ sign) - sign; } -#endif /* BITSTREAM_H */ +#endif /* AVCODEC_BITSTREAM_H */