LCOV - code coverage report
Current view: top level - libavcodec - cabac_functions.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 32 34 94.1 %
Date: 2017-12-18 06:23:41 Functions: 6 6 100.0 %

          Line data    Source code
       1             : /*
       2             :  * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
       3             :  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
       4             :  *
       5             :  * This file is part of FFmpeg.
       6             :  *
       7             :  * FFmpeg is free software; you can redistribute it and/or
       8             :  * modify it under the terms of the GNU Lesser General Public
       9             :  * License as published by the Free Software Foundation; either
      10             :  * version 2.1 of the License, or (at your option) any later version.
      11             :  *
      12             :  * FFmpeg is distributed in the hope that it will be useful,
      13             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15             :  * Lesser General Public License for more details.
      16             :  *
      17             :  * You should have received a copy of the GNU Lesser General Public
      18             :  * License along with FFmpeg; if not, write to the Free Software
      19             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      20             :  */
      21             : 
      22             : /**
      23             :  * @file
      24             :  * Context Adaptive Binary Arithmetic Coder inline functions
      25             :  */
      26             : 
      27             : #ifndef AVCODEC_CABAC_FUNCTIONS_H
      28             : #define AVCODEC_CABAC_FUNCTIONS_H
      29             : 
      30             : #include <stdint.h>
      31             : 
      32             : #include "cabac.h"
      33             : #include "config.h"
      34             : 
      35             : #ifndef UNCHECKED_BITSTREAM_READER
      36             : #define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
      37             : #endif
      38             : 
      39             : #if ARCH_AARCH64
      40             : #   include "aarch64/cabac.h"
      41             : #endif
      42             : #if ARCH_ARM
      43             : #   include "arm/cabac.h"
      44             : #endif
      45             : #if ARCH_X86
      46             : #   include "x86/cabac.h"
      47             : #endif
      48             : 
      49             : static const uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
      50             : static const uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
      51             : static const uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
      52             : static const uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;
      53             : 
      54             : #if !defined(get_cabac_bypass) || !defined(get_cabac_terminate)
      55       21705 : static void refill(CABACContext *c){
      56             : #if CABAC_BITS == 16
      57       21705 :         c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
      58             : #else
      59             :         c->low+= c->bytestream[0]<<1;
      60             : #endif
      61       21705 :     c->low -= CABAC_MASK;
      62             : #if !UNCHECKED_BITSTREAM_READER
      63       19673 :     if (c->bytestream < c->bytestream_end)
      64             : #endif
      65       21662 :         c->bytestream += CABAC_BITS / 8;
      66       21705 : }
      67             : #endif
      68             : 
      69             : #ifndef get_cabac_terminate
      70     9488724 : static inline void renorm_cabac_decoder_once(CABACContext *c){
      71     9488724 :     int shift= (uint32_t)(c->range - 0x100)>>31;
      72     9488724 :     c->range<<= shift;
      73     9488724 :     c->low  <<= shift;
      74     9488724 :     if(!(c->low & CABAC_MASK))
      75       21705 :         refill(c);
      76     9488724 : }
      77             : #endif
      78             : 
      79             : #ifndef get_cabac_inline
      80             : static void refill2(CABACContext *c){
      81             :     int i;
      82             :     unsigned x;
      83             : #if !HAVE_FAST_CLZ
      84             :     x= c->low ^ (c->low-1);
      85             :     i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
      86             : #else
      87             :     i = ff_ctz(c->low) - CABAC_BITS;
      88             : #endif
      89             : 
      90             :     x= -CABAC_MASK;
      91             : 
      92             : #if CABAC_BITS == 16
      93             :         x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
      94             : #else
      95             :         x+= c->bytestream[0]<<1;
      96             : #endif
      97             : 
      98             :     c->low += x<<i;
      99             : #if !UNCHECKED_BITSTREAM_READER
     100             :     if (c->bytestream < c->bytestream_end)
     101             : #endif
     102             :         c->bytestream += CABAC_BITS/8;
     103             : }
     104             : #endif
     105             : 
     106             : #ifndef get_cabac_inline
     107             : static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
     108             :     int s = *state;
     109             :     int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
     110             :     int bit, lps_mask;
     111             : 
     112             :     c->range -= RangeLPS;
     113             :     lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
     114             : 
     115             :     c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
     116             :     c->range += (RangeLPS - c->range) & lps_mask;
     117             : 
     118             :     s^=lps_mask;
     119             :     *state= (ff_h264_mlps_state+128)[s];
     120             :     bit= s&1;
     121             : 
     122             :     lps_mask= ff_h264_norm_shift[c->range];
     123             :     c->range<<= lps_mask;
     124             :     c->low  <<= lps_mask;
     125             :     if(!(c->low & CABAC_MASK))
     126             :         refill2(c);
     127             :     return bit;
     128             : }
     129             : #endif
     130             : 
     131    76684508 : static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
     132    76684508 :     return get_cabac_inline(c,state);
     133             : }
     134             : 
     135   963833780 : static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
     136   963833780 :     return get_cabac_inline(c,state);
     137             : }
     138             : 
     139             : #ifndef get_cabac_bypass
     140             : static int av_unused get_cabac_bypass(CABACContext *c){
     141             :     int range;
     142             :     c->low += c->low;
     143             : 
     144             :     if(!(c->low & CABAC_MASK))
     145             :         refill(c);
     146             : 
     147             :     range= c->range<<(CABAC_BITS+1);
     148             :     if(c->low < range){
     149             :         return 0;
     150             :     }else{
     151             :         c->low -= range;
     152             :         return 1;
     153             :     }
     154             : }
     155             : #endif
     156             : 
     157             : #ifndef get_cabac_bypass_sign
     158             : static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
     159             :     int range, mask;
     160             :     c->low += c->low;
     161             : 
     162             :     if(!(c->low & CABAC_MASK))
     163             :         refill(c);
     164             : 
     165             :     range= c->range<<(CABAC_BITS+1);
     166             :     c->low -= range;
     167             :     mask= c->low >> 31;
     168             :     range &= mask;
     169             :     c->low += range;
     170             :     return (val^mask)-mask;
     171             : }
     172             : #endif
     173             : 
     174             : /**
     175             :  * @return the number of bytes read or 0 if no end
     176             :  */
     177             : #ifndef get_cabac_terminate
     178     9552695 : static int av_unused get_cabac_terminate(CABACContext *c){
     179     9552695 :     c->range -= 2;
     180     9552695 :     if(c->low < c->range<<(CABAC_BITS+1)){
     181     9488724 :         renorm_cabac_decoder_once(c);
     182     9488724 :         return 0;
     183             :     }else{
     184       63971 :         return c->bytestream - c->bytestream_start;
     185             :     }
     186             : }
     187             : #endif
     188             : 
     189             : /**
     190             :  * Skip @p n bytes and reset the decoder.
     191             :  * @return the address of the first skipped byte or NULL if there's less than @p n bytes left
     192             :  */
     193             : #ifndef skip_bytes
     194       20007 : static av_unused const uint8_t* skip_bytes(CABACContext *c, int n) {
     195       20007 :     const uint8_t *ptr = c->bytestream;
     196             : 
     197       20007 :     if (c->low & 0x1)
     198        1143 :         ptr--;
     199             : #if CABAC_BITS == 16
     200       20007 :     if (c->low & 0x1FF)
     201       10892 :         ptr--;
     202             : #endif
     203       20007 :     if ((int) (c->bytestream_end - ptr) < n)
     204           0 :         return NULL;
     205       20007 :     if (ff_init_cabac_decoder(c, ptr + n, c->bytestream_end - ptr - n) < 0)
     206           0 :         return NULL;
     207             : 
     208       20007 :     return ptr;
     209             : }
     210             : #endif
     211             : 
     212             : #endif /* AVCODEC_CABAC_FUNCTIONS_H */

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