mirror of https://github.com/FFmpeg/FFmpeg.git
put_bits.h. Originally committed as revision 18461 to svn://svn.ffmpeg.org/ffmpeg/trunkrelease/0.6
Stefano Sabatini
16 years ago
parent
77daaf6748
commit
b275500706
30 changed files with 340 additions and 287 deletions
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/*
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* copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/**
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* @file libavcodec/put_bits.h |
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* bitstream writer API |
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*/ |
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#ifndef AVCODEC_PUT_BITS_H |
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#define AVCODEC_PUT_BITS_H |
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#include <stdint.h> |
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#include <stdlib.h> |
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#include <assert.h> |
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#include "libavutil/bswap.h" |
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#include "libavutil/common.h" |
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#include "libavutil/intreadwrite.h" |
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#include "libavutil/log.h" |
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#include "mathops.h" |
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//#define ALT_BITSTREAM_WRITER
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//#define ALIGNED_BITSTREAM_WRITER
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/* buf and buf_end must be present and used by every alternative writer. */ |
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typedef struct PutBitContext { |
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#ifdef ALT_BITSTREAM_WRITER |
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uint8_t *buf, *buf_end; |
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int index; |
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#else |
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uint32_t bit_buf; |
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int bit_left; |
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uint8_t *buf, *buf_ptr, *buf_end; |
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#endif |
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int size_in_bits; |
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} PutBitContext; |
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/**
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* Initializes the PutBitContext \p s. |
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* |
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* @param buffer the buffer where to put bits |
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* @param buffer_size the size in bytes of \p buffer |
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*/ |
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static inline void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size) |
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{ |
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if(buffer_size < 0) { |
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buffer_size = 0; |
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buffer = NULL; |
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} |
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s->size_in_bits= 8*buffer_size; |
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s->buf = buffer; |
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s->buf_end = s->buf + buffer_size; |
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#ifdef ALT_BITSTREAM_WRITER |
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s->index=0; |
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((uint32_t*)(s->buf))[0]=0; |
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// memset(buffer, 0, buffer_size);
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#else |
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s->buf_ptr = s->buf; |
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s->bit_left=32; |
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s->bit_buf=0; |
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#endif |
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} |
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/**
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* Returns the total number of bits written to the bitstream. |
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*/ |
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static inline int put_bits_count(PutBitContext *s) |
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{ |
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#ifdef ALT_BITSTREAM_WRITER |
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return s->index; |
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#else |
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return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left; |
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#endif |
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} |
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/**
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* Pads the end of the output stream with zeros. |
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*/ |
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static inline void flush_put_bits(PutBitContext *s) |
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{ |
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#ifdef ALT_BITSTREAM_WRITER |
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align_put_bits(s); |
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#else |
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#ifndef BITSTREAM_WRITER_LE |
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s->bit_buf<<= s->bit_left; |
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#endif |
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while (s->bit_left < 32) { |
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/* XXX: should test end of buffer */ |
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#ifdef BITSTREAM_WRITER_LE |
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*s->buf_ptr++=s->bit_buf; |
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s->bit_buf>>=8; |
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#else |
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*s->buf_ptr++=s->bit_buf >> 24; |
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s->bit_buf<<=8; |
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#endif |
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s->bit_left+=8; |
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} |
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s->bit_left=32; |
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s->bit_buf=0; |
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#endif |
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} |
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/**
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* Pads the bitstream with zeros up to the next byte boundary. |
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*/ |
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void align_put_bits(PutBitContext *s); |
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/**
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* Puts the string \p s in the bitstream. |
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* |
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* @param terminate_string 0-terminates the written string if value is 1 |
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*/ |
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void ff_put_string(PutBitContext * pbc, const char *s, int terminate_string); |
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/**
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* Copies the content of \p src to the bitstream. |
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* |
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* @param length the number of bits of \p src to copy |
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*/ |
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void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length); |
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static inline void put_bits(PutBitContext *s, int n, unsigned int value) |
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#ifndef ALT_BITSTREAM_WRITER |
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{ |
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unsigned int bit_buf; |
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int bit_left; |
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// printf("put_bits=%d %x\n", n, value);
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assert(n == 32 || value < (1U << n)); |
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bit_buf = s->bit_buf; |
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bit_left = s->bit_left; |
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// printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
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/* XXX: optimize */ |
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#ifdef BITSTREAM_WRITER_LE |
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bit_buf |= value << (32 - bit_left); |
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if (n >= bit_left) { |
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#if !HAVE_FAST_UNALIGNED |
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if (3 & (intptr_t) s->buf_ptr) { |
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AV_WL32(s->buf_ptr, bit_buf); |
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} else |
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#endif |
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*(uint32_t *)s->buf_ptr = le2me_32(bit_buf); |
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s->buf_ptr+=4; |
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bit_buf = (bit_left==32)?0:value >> bit_left; |
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bit_left+=32; |
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} |
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bit_left-=n; |
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#else |
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if (n < bit_left) { |
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bit_buf = (bit_buf<<n) | value; |
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bit_left-=n; |
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} else { |
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bit_buf<<=bit_left; |
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bit_buf |= value >> (n - bit_left); |
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#if !HAVE_FAST_UNALIGNED |
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if (3 & (intptr_t) s->buf_ptr) { |
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AV_WB32(s->buf_ptr, bit_buf); |
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} else |
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#endif |
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*(uint32_t *)s->buf_ptr = be2me_32(bit_buf); |
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//printf("bitbuf = %08x\n", bit_buf);
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s->buf_ptr+=4; |
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bit_left+=32 - n; |
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bit_buf = value; |
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} |
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#endif |
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s->bit_buf = bit_buf; |
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s->bit_left = bit_left; |
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} |
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#else /* ALT_BITSTREAM_WRITER defined */ |
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{ |
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# ifdef ALIGNED_BITSTREAM_WRITER |
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# if ARCH_X86 |
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__asm__ volatile( |
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"movl %0, %%ecx \n\t" |
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"xorl %%eax, %%eax \n\t" |
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"shrdl %%cl, %1, %%eax \n\t" |
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"shrl %%cl, %1 \n\t" |
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"movl %0, %%ecx \n\t" |
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"shrl $3, %%ecx \n\t" |
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"andl $0xFFFFFFFC, %%ecx \n\t" |
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"bswapl %1 \n\t" |
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"orl %1, (%2, %%ecx) \n\t" |
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"bswapl %%eax \n\t" |
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"addl %3, %0 \n\t" |
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"movl %%eax, 4(%2, %%ecx) \n\t" |
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: "=&r" (s->index), "=&r" (value) |
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: "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n)) |
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: "%eax", "%ecx" |
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); |
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# else |
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int index= s->index; |
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uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5); |
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value<<= 32-n; |
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ptr[0] |= be2me_32(value>>(index&31)); |
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ptr[1] = be2me_32(value<<(32-(index&31))); |
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//if(n>24) printf("%d %d\n", n, value);
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index+= n; |
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s->index= index; |
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# endif |
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# else //ALIGNED_BITSTREAM_WRITER
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# if ARCH_X86 |
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__asm__ volatile( |
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"movl $7, %%ecx \n\t" |
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"andl %0, %%ecx \n\t" |
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"addl %3, %%ecx \n\t" |
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"negl %%ecx \n\t" |
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"shll %%cl, %1 \n\t" |
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"bswapl %1 \n\t" |
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"movl %0, %%ecx \n\t" |
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"shrl $3, %%ecx \n\t" |
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"orl %1, (%%ecx, %2) \n\t" |
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"addl %3, %0 \n\t" |
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"movl $0, 4(%%ecx, %2) \n\t" |
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: "=&r" (s->index), "=&r" (value) |
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: "r" (s->buf), "r" (n), "0" (s->index), "1" (value) |
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: "%ecx" |
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); |
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# else |
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int index= s->index; |
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uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3)); |
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ptr[0] |= be2me_32(value<<(32-n-(index&7) )); |
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ptr[1] = 0; |
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//if(n>24) printf("%d %d\n", n, value);
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index+= n; |
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s->index= index; |
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# endif |
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# endif //!ALIGNED_BITSTREAM_WRITER
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} |
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#endif |
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static inline void put_sbits(PutBitContext *pb, int bits, int32_t val) |
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{ |
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assert(bits >= 0 && bits <= 31); |
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put_bits(pb, bits, val & ((1<<bits)-1)); |
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} |
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static inline uint8_t* pbBufPtr(PutBitContext *s) |
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{ |
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#ifdef ALT_BITSTREAM_WRITER |
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return s->buf + (s->index>>3); |
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#else |
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return s->buf_ptr; |
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#endif |
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} |
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/**
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* Skips the given number of bytes. |
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* PutBitContext must be flushed & aligned to a byte boundary before calling this. |
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*/ |
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static inline void skip_put_bytes(PutBitContext *s, int n){ |
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assert((put_bits_count(s)&7)==0); |
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#ifdef ALT_BITSTREAM_WRITER |
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FIXME may need some cleaning of the buffer |
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s->index += n<<3; |
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#else |
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assert(s->bit_left==32); |
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s->buf_ptr += n; |
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#endif |
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} |
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/**
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* Skips the given number of bits. |
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* Must only be used if the actual values in the bitstream do not matter. |
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* If \p n is 0 the behavior is undefined. |
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*/ |
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static inline void skip_put_bits(PutBitContext *s, int n){ |
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#ifdef ALT_BITSTREAM_WRITER |
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s->index += n; |
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#else |
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s->bit_left -= n; |
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s->buf_ptr-= s->bit_left>>5; |
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s->bit_left &= 31; |
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#endif |
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} |
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/**
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* Changes the end of the buffer. |
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* |
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* @param size the new size in bytes of the buffer where to put bits |
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*/ |
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static inline void set_put_bits_buffer_size(PutBitContext *s, int size){ |
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s->buf_end= s->buf + size; |
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} |
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#endif /* AVCODEC_PUT_BITS_H */ |
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