/* * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at> * * This file is part of Libav. * * 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. * * 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * bitstream writer API */ #ifndef AVCODEC_PUT_BITS_H #define AVCODEC_PUT_BITS_H #include <stdint.h> #include <stdlib.h> #include <assert.h> #include "libavutil/bswap.h" #include "libavutil/common.h" #include "libavutil/intreadwrite.h" #include "libavutil/log.h" #include "mathops.h" #include "config.h" //#define ALT_BITSTREAM_WRITER //#define ALIGNED_BITSTREAM_WRITER /* 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 int size_in_bits; } PutBitContext; /** * Initialize the PutBitContext s. * * @param buffer the buffer where to put bits * @param buffer_size the size in bytes of buffer */ static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size) { if(buffer_size < 0) { buffer_size = 0; buffer = NULL; } s->size_in_bits= 8*buffer_size; 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 total number of bits written to the bitstream. */ 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 } #if defined(ALT_BITSTREAM_WRITER) || defined(BITSTREAM_WRITER_LE) #define align_put_bits align_put_bits_unsupported_here #define ff_put_string ff_put_string_unsupported_here #define ff_copy_bits ff_copy_bits_unsupported_here #else /** * Pad the bitstream with zeros up to the next byte boundary. */ void align_put_bits(PutBitContext *s); /** * Put the string string in the bitstream. * * @param terminate_string 0-terminates the written string if value is 1 */ void ff_put_string(PutBitContext *pb, const char *string, int terminate_string); /** * Copy the content of src to the bitstream. * * @param length the number of bits of src to copy */ void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length); #endif /** * Write up to 31 bits into a bitstream. * Use put_bits32 to write 32 bits. */ static inline void put_bits(PutBitContext *s, int n, unsigned int value) #ifndef ALT_BITSTREAM_WRITER { unsigned int bit_buf; int bit_left; // printf("put_bits=%d %x\n", n, value); assert(n <= 31 && 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 */ #ifdef BITSTREAM_WRITER_LE bit_buf |= value << (32 - bit_left); if (n >= bit_left) { #if !HAVE_FAST_UNALIGNED if (3 & (intptr_t) s->buf_ptr) { AV_WL32(s->buf_ptr, bit_buf); } else #endif *(uint32_t *)s->buf_ptr = av_le2ne32(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); #if !HAVE_FAST_UNALIGNED if (3 & (intptr_t) s->buf_ptr) { AV_WB32(s->buf_ptr, bit_buf); } else #endif *(uint32_t *)s->buf_ptr = av_be2ne32(bit_buf); //printf("bitbuf = %08x\n", bit_buf); s->buf_ptr+=4; bit_left+=32 - n; bit_buf = value; } #endif s->bit_buf = bit_buf; s->bit_left = bit_left; } #else /* ALT_BITSTREAM_WRITER defined */ { # ifdef ALIGNED_BITSTREAM_WRITER # if 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] |= av_be2ne32(value>>(index&31)); ptr[1] = av_be2ne32(value<<(32-(index&31))); //if(n>24) printf("%d %d\n", n, value); index+= n; s->index= index; # endif # else //ALIGNED_BITSTREAM_WRITER # if 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] |= av_be2ne32(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 } #endif static inline void put_sbits(PutBitContext *pb, int n, int32_t value) { assert(n >= 0 && n <= 31); put_bits(pb, n, value & ((1<<n)-1)); } /** * Write exactly 32 bits into a bitstream. */ static void av_unused put_bits32(PutBitContext *s, uint32_t value) { int lo = value & 0xffff; int hi = value >> 16; #ifdef BITSTREAM_WRITER_LE put_bits(s, 16, lo); put_bits(s, 16, hi); #else put_bits(s, 16, hi); put_bits(s, 16, lo); #endif } /** * Return the pointer to the byte where the bitstream writer will put * the next bit. */ static inline uint8_t* put_bits_ptr(PutBitContext *s) { #ifdef ALT_BITSTREAM_WRITER return s->buf + (s->index>>3); #else return s->buf_ptr; #endif } /** * Skip the given number of bytes. * 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 } /** * Skip the given number of bits. * Must only be used if the actual values in the bitstream do not matter. * If n is 0 the behavior is undefined. */ 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-= 4*(s->bit_left>>5); s->bit_left &= 31; #endif } /** * Change the end of the buffer. * * @param size the new size in bytes of the buffer where to put bits */ static inline void set_put_bits_buffer_size(PutBitContext *s, int size) { s->buf_end= s->buf + size; } #endif /* AVCODEC_PUT_BITS_H */