yading@10: /*
yading@10:  * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
yading@10:  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Context Adaptive Binary Arithmetic Coder inline functions
yading@10:  */
yading@10: 
yading@10: #ifndef AVCODEC_CABAC_FUNCTIONS_H
yading@10: #define AVCODEC_CABAC_FUNCTIONS_H
yading@10: 
yading@10: #include <stdint.h>
yading@10: 
yading@10: #include "cabac.h"
yading@10: #include "config.h"
yading@10: 
yading@10: #if ARCH_X86
yading@10: #   include "x86/cabac.h"
yading@10: #endif
yading@10: 
yading@10: extern uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63];
yading@10: static uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
yading@10: static uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
yading@10: static uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
yading@10: static uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
yading@10: 
yading@10: static void refill(CABACContext *c){
yading@10: #if CABAC_BITS == 16
yading@10:         c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
yading@10: #else
yading@10:         c->low+= c->bytestream[0]<<1;
yading@10: #endif
yading@10:     c->low -= CABAC_MASK;
yading@10:     c->bytestream += CABAC_BITS / 8;
yading@10: }
yading@10: 
yading@10: static inline void renorm_cabac_decoder_once(CABACContext *c){
yading@10:     int shift= (uint32_t)(c->range - 0x100)>>31;
yading@10:     c->range<<= shift;
yading@10:     c->low  <<= shift;
yading@10:     if(!(c->low & CABAC_MASK))
yading@10:         refill(c);
yading@10: }
yading@10: 
yading@10: #ifndef get_cabac_inline
yading@10: static void refill2(CABACContext *c){
yading@10:     int i, x;
yading@10: 
yading@10:     x= c->low ^ (c->low-1);
yading@10:     i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
yading@10: 
yading@10:     x= -CABAC_MASK;
yading@10: 
yading@10: #if CABAC_BITS == 16
yading@10:         x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
yading@10: #else
yading@10:         x+= c->bytestream[0]<<1;
yading@10: #endif
yading@10: 
yading@10:     c->low += x<<i;
yading@10:     c->bytestream += CABAC_BITS/8;
yading@10: }
yading@10: 
yading@10: static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
yading@10:     int s = *state;
yading@10:     int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
yading@10:     int bit, lps_mask;
yading@10: 
yading@10:     c->range -= RangeLPS;
yading@10:     lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
yading@10: 
yading@10:     c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
yading@10:     c->range += (RangeLPS - c->range) & lps_mask;
yading@10: 
yading@10:     s^=lps_mask;
yading@10:     *state= (ff_h264_mlps_state+128)[s];
yading@10:     bit= s&1;
yading@10: 
yading@10:     lps_mask= ff_h264_norm_shift[c->range];
yading@10:     c->range<<= lps_mask;
yading@10:     c->low  <<= lps_mask;
yading@10:     if(!(c->low & CABAC_MASK))
yading@10:         refill2(c);
yading@10:     return bit;
yading@10: }
yading@10: #endif
yading@10: 
yading@10: static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
yading@10:     return get_cabac_inline(c,state);
yading@10: }
yading@10: 
yading@10: static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
yading@10:     return get_cabac_inline(c,state);
yading@10: }
yading@10: 
yading@10: static int av_unused get_cabac_bypass(CABACContext *c){
yading@10:     int range;
yading@10:     c->low += c->low;
yading@10: 
yading@10:     if(!(c->low & CABAC_MASK))
yading@10:         refill(c);
yading@10: 
yading@10:     range= c->range<<(CABAC_BITS+1);
yading@10:     if(c->low < range){
yading@10:         return 0;
yading@10:     }else{
yading@10:         c->low -= range;
yading@10:         return 1;
yading@10:     }
yading@10: }
yading@10: 
yading@10: 
yading@10: #ifndef get_cabac_bypass_sign
yading@10: static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
yading@10:     int range, mask;
yading@10:     c->low += c->low;
yading@10: 
yading@10:     if(!(c->low & CABAC_MASK))
yading@10:         refill(c);
yading@10: 
yading@10:     range= c->range<<(CABAC_BITS+1);
yading@10:     c->low -= range;
yading@10:     mask= c->low >> 31;
yading@10:     range &= mask;
yading@10:     c->low += range;
yading@10:     return (val^mask)-mask;
yading@10: }
yading@10: #endif
yading@10: 
yading@10: /**
yading@10:  *
yading@10:  * @return the number of bytes read or 0 if no end
yading@10:  */
yading@10: static int av_unused get_cabac_terminate(CABACContext *c){
yading@10:     c->range -= 2;
yading@10:     if(c->low < c->range<<(CABAC_BITS+1)){
yading@10:         renorm_cabac_decoder_once(c);
yading@10:         return 0;
yading@10:     }else{
yading@10:         return c->bytestream - c->bytestream_start;
yading@10:     }
yading@10: }
yading@10: 
yading@10: #endif /* AVCODEC_CABAC_FUNCTIONS_H */