bitstream.h
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上传日期:2022-07-11
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- /*
- * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
- *
- * This file is part of FFmpeg.
- *
- * FFmpeg 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,
- * 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
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
- /**
- * @file bitstream.h
- * bitstream api header.
- */
- #ifndef AVCODEC_BITSTREAM_H
- #define AVCODEC_BITSTREAM_H
- //#include <stdint.h>
- #include <stdlib.h>
- #include <assert.h>
- //#include "bswap.h"
- //#include "common.h"
- //#include "intreadwrite.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_ARM
- # define A32_BITSTREAM_READER
- # else
- # define ALT_BITSTREAM_READER
- //#define LIBMPEG2_BITSTREAM_READER
- //#define A32_BITSTREAM_READER
- # endif
- #endif
- 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, %0nt"
- : "+r" (a)
- : "ic" ((uint8_t)(-s))
- );
- return a;
- }
- static inline uint32_t NEG_USR32(uint32_t a, int8_t s){
- __asm__ ("shrl %1, %0nt"
- : "+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
- /* bit output */
- /* 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;
- static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
- {
- if(buffer_size < 0) {
- buffer_size = 0;
- buffer = NULL;
- }
- 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);
- #else
- s->buf_ptr = s->buf;
- s->bit_left=32;
- s->bit_buf=0;
- #endif
- }
- /* return the number of bits output */
- static inline int put_bits_count(PutBitContext *s)
- {
- #ifdef ALT_BITSTREAM_WRITER
- return s->index;
- #else
- return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
- #endif
- }
- /* pad the end of the output stream with zeros */
- static inline void flush_put_bits(PutBitContext *s)
- {
- #ifdef ALT_BITSTREAM_WRITER
- align_put_bits(s);
- #else
- #ifndef BITSTREAM_WRITER_LE
- s->bit_buf<<= s->bit_left;
- #endif
- while (s->bit_left < 32) {
- /* XXX: should test end of buffer */
- #ifdef BITSTREAM_WRITER_LE
- *s->buf_ptr++=s->bit_buf;
- s->bit_buf>>=8;
- #else
- *s->buf_ptr++=s->bit_buf >> 24;
- s->bit_buf<<=8;
- #endif
- s->bit_left+=8;
- }
- s->bit_left=32;
- s->bit_buf=0;
- #endif
- }
- void align_put_bits(PutBitContext *s);
- void ff_put_string(PutBitContext * pbc, const char *s, int put_zero);
- void ff_copy_bits(PutBitContext *pb, const 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
- typedef struct VLC {
- int bits;
- VLC_TYPE (*table)[2]; ///< code, bits
- int table_size, table_allocated;
- } VLC;
- typedef struct RL_VLC_ELEM {
- int16_t level;
- int8_t len;
- uint8_t run;
- } RL_VLC_ELEM;
- #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 %xn", 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=%xn", n, value, bit_cnt, bit_buf);
- /* XXX: optimize */
- #ifdef BITSTREAM_WRITER_LE
- bit_buf |= value << (32 - bit_left);
- if (n >= bit_left) {
- #ifndef HAVE_FAST_UNALIGNED
- if (3 & (intptr_t) s->buf_ptr) {
- s->buf_ptr[0] = bit_buf ;
- s->buf_ptr[1] = bit_buf >> 8;
- s->buf_ptr[2] = bit_buf >> 16;
- s->buf_ptr[3] = bit_buf >> 24;
- } else
- #endif
- *(uint32_t *)s->buf_ptr = le2me_32(bit_buf);
- s->buf_ptr+=4;
- bit_buf = (bit_left==32)?0:value >> bit_left;
- bit_left+=32;
- }
- bit_left-=n;
- #else
- if (n < bit_left) {
- bit_buf = (bit_buf<<n) | value;
- bit_left-=n;
- } else {
- bit_buf<<=bit_left;
- bit_buf |= value >> (n - bit_left);
- #ifndef HAVE_FAST_UNALIGNED
- 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 = %08xn", bit_buf);
- s->buf_ptr+=4;
- bit_left+=32 - n;
- bit_buf = value;
- }
- #endif
- s->bit_buf = bit_buf;
- s->bit_left = bit_left;
- }
- #endif
- #ifdef ALT_BITSTREAM_WRITER
- static inline void put_bits(PutBitContext *s, int n, unsigned int value)
- {
- # ifdef ALIGNED_BITSTREAM_WRITER
- # if defined(ARCH_X86)
- __asm__ volatile(
- "movl %0, %%ecx nt"
- "xorl %%eax, %%eax nt"
- "shrdl %%cl, %1, %%eax nt"
- "shrl %%cl, %1 nt"
- "movl %0, %%ecx nt"
- "shrl $3, %%ecx nt"
- "andl $0xFFFFFFFC, %%ecx nt"
- "bswapl %1 nt"
- "orl %1, (%2, %%ecx) nt"
- "bswapl %%eax nt"
- "addl %3, %0 nt"
- "movl %%eax, 4(%2, %%ecx) nt"
- : "=&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 %dn", n, value);
- index+= n;
- s->index= index;
- # endif
- # else //ALIGNED_BITSTREAM_WRITER
- # if defined(ARCH_X86)
- __asm__ volatile(
- "movl $7, %%ecx nt"
- "andl %0, %%ecx nt"
- "addl %3, %%ecx nt"
- "negl %%ecx nt"
- "shll %%cl, %1 nt"
- "bswapl %1 nt"
- "movl %0, %%ecx nt"
- "shrl $3, %%ecx nt"
- "orl %1, (%%ecx, %2) nt"
- "addl %3, %0 nt"
- "movl $0, 4(%%ecx, %2) nt"
- : "=&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 %dn", n, value);
- index+= n;
- s->index= index;
- # endif
- # endif //!ALIGNED_BITSTREAM_WRITER
- }
- #endif
- static inline void put_sbits(PutBitContext *pb, int bits, int32_t val)
- {
- assert(bits >= 0 && bits <= 31);
- put_bits(pb, bits, val & ((1<<bits)-1));
- }
- static inline uint8_t* pbBufPtr(PutBitContext *s)
- {
- #ifdef ALT_BITSTREAM_WRITER
- return s->buf + (s->index>>3);
- #else
- return s->buf_ptr;
- #endif
- }
- /**
- *
- * 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
- }
- /**
- * 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;
- #else
- s->bit_left -= n;
- s->buf_ptr-= s->bit_left>>5;
- s->bit_left &= 31;
- #endif
- }
- /**
- * Changes the end of the buffer.
- */
- static inline void set_put_bits_buffer_size(PutBitContext *s, int size){
- s->buf_end= s->buf + size;
- }
- /* Bitstream reader API docs:
- name
- arbitrary 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
- */
- #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= AV_RL32( ((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= AV_RB32( ((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;
- # define UPDATE_CACHE(name, gb)
- if(name##_bit_count >= 0){
- name##_cache+= AV_RB16(name##_buffer_ptr) << name##_bit_count;
- name##_buffer_ptr+=2;
- name##_bit_count-= 16;
- }
- # 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<<name##_bit_count;
- name##_buffer_ptr++;
- name##_bit_count-= 32;
- }
- #if defined(ARCH_X86)
- # define SKIP_CACHE(name, gb, num)
- __asm__(
- "shldl %2, %1, %0 nt"
- "shll %2, %1 nt"
- : "+r" (name##_cache0), "+r" (name##_cache1)
- : "Ic" ((uint8_t)(num))
- );
- #else
- # define SKIP_CACHE(name, gb, num)
- name##_cache0 <<= (num);
- name##_cache0 |= NEG_USR32(name##_cache1,num);
- name##_cache1 <<= (num);
- #endif
- # 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##_cache0, num)
- # define SHOW_SBITS(name, gb, num)
- NEG_SSR32(name##_cache0, num)
- # define GET_CACHE(name, gb)
- (name##_cache0)
- static inline int get_bits_count(GetBitContext *s){
- return ((uint8_t*)s->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)
- }
- #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;
- }
- /**
- * 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;
- }
- /**
- * 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;
- }
- 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)
- }
- 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;
- #else
- return get_bits(s, 1);
- #endif
- }
- static inline unsigned int show_bits1(GetBitContext *s){
- return show_bits(s, 1);
- }
- static inline void skip_bits1(GetBitContext *s){
- skip_bits(s, 1);
- }
- /**
- * 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);
- #else
- int ret= get_bits(s, 16) << (n-16);
- return ret | get_bits(s, n-16);
- #endif
- }
- }
- /**
- * 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;
- }
- }
- static inline int check_marker(GetBitContext *s, const char *msg)
- {
- int bit= get_bits1(s);
- if(!bit)
- av_log(NULL, AV_LOG_INFO, "Marker bit missing %sn", msg);
- return bit;
- }
- /**
- * 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)
- {
- 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
- }
- static inline void align_get_bits(GetBitContext *s)
- {
- int n= (-get_bits_count(s)) & 7;
- if(n) skip_bits(s, n);
- }
- #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 ///< VERY strongly deprecated and forbidden
- #define INIT_VLC_LE 2
- #define INIT_VLC_USE_NEW_STATIC 4
- void free_vlc(VLC *vlc);
- #define INIT_VLC_STATIC(vlc, bits, a,b,c,d,e,f,g, static_size)
- {
- static VLC_TYPE table[static_size][2];
- (vlc)->table= table;
- (vlc)->table_allocated= static_size;
- init_vlc(vlc, bits, a,b,c,d,e,f,g, INIT_VLC_USE_NEW_STATIC);
- }
- /**
- *
- * 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)
- }
- #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)
- }
- /**
- * 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()
- * @param max_depth is the number of times bits bits must be read to completely
- * 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)
- {
- 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);
- }
- for(i=n; i<24; i++)
- av_log(NULL, AV_LOG_DEBUG, " ");
- }
- 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:%dn", 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:%dn", bits2, len, r, pos, file, func, line);
- return r;
- }
- 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:%dn", show, n, r, get_bits_count(s)-n, file, func, line);
- return r;
- }
- #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 0;
- else
- return get_bits1(gb) + 1;
- }
- static inline int decode210(GetBitContext *gb){
- if (get_bits1(gb))
- return 0;
- else
- return 2 - get_bits1(gb);
- }
- #endif /* AVCODEC_BITSTREAM_H */