/*
  * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
  * Copyright (c) 2003 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
  * Context Adaptive Binary Arithmetic Coder inline functions
  */
 
 #ifndef AVCODEC_CABAC_FUNCTIONS_H
 #define AVCODEC_CABAC_FUNCTIONS_H
 
 #include <stdint.h>
 
 #include "cabac.h"
 #include "config.h"
 
 #if ARCH_X86
 #   include "x86/cabac.h"
 #endif
 

 extern uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63];
 static uint8_t * const ff_h264_norm_shift = ff_h264_cabac_tables + H264_NORM_SHIFT_OFFSET;
 static uint8_t * const ff_h264_lps_range = ff_h264_cabac_tables + H264_LPS_RANGE_OFFSET;
 static uint8_t * const ff_h264_mlps_state = ff_h264_cabac_tables + H264_MLPS_STATE_OFFSET;
 static uint8_t * const ff_h264_last_coeff_flag_offset_8x8 = ff_h264_cabac_tables + H264_LAST_COEFF_FLAG_OFFSET_8x8_OFFSET;

 
 static void refill(CABACContext *c){
 #if CABAC_BITS == 16
         c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
 #else
         c->low+= c->bytestream[0]<<1;
 #endif
     c->low -= CABAC_MASK;

     c->bytestream += CABAC_BITS / 8;

 }
 
 static inline void renorm_cabac_decoder_once(CABACContext *c){
     int shift= (uint32_t)(c->range - 0x100)>>31;
     c->range<<= shift;
     c->low  <<= shift;
     if(!(c->low & CABAC_MASK))
         refill(c);
 }
 
 #ifndef get_cabac_inline
 static void refill2(CABACContext *c){
     int i, x;
 
     x= c->low ^ (c->low-1);
     i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
 
     x= -CABAC_MASK;
 
 #if CABAC_BITS == 16
         x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
 #else
         x+= c->bytestream[0]<<1;
 #endif
 
     c->low += x<<i;

     c->bytestream += CABAC_BITS/8;

 }
 
 static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
     int s = *state;
     int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
     int bit, lps_mask;
 
     c->range -= RangeLPS;
     lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
 
     c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
     c->range += (RangeLPS - c->range) & lps_mask;
 
     s^=lps_mask;
     *state= (ff_h264_mlps_state+128)[s];
     bit= s&1;
 
     lps_mask= ff_h264_norm_shift[c->range];
     c->range<<= lps_mask;
     c->low  <<= lps_mask;
     if(!(c->low & CABAC_MASK))
         refill2(c);
     return bit;
 }
 #endif
 
 static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
     return get_cabac_inline(c,state);
 }
 
 static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
     return get_cabac_inline(c,state);
 }
 
 static int av_unused get_cabac_bypass(CABACContext *c){
     int range;
     c->low += c->low;
 
     if(!(c->low & CABAC_MASK))
         refill(c);
 
     range= c->range<<(CABAC_BITS+1);
     if(c->low < range){
         return 0;
     }else{
         c->low -= range;
         return 1;
     }
 }
 
 
 #ifndef get_cabac_bypass_sign
 static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
     int range, mask;
     c->low += c->low;
 
     if(!(c->low & CABAC_MASK))
         refill(c);
 
     range= c->range<<(CABAC_BITS+1);
     c->low -= range;
     mask= c->low >> 31;
     range &= mask;
     c->low += range;
     return (val^mask)-mask;
 }
 #endif
 
 /**
  *
  * @return the number of bytes read or 0 if no end
  */
 static int av_unused get_cabac_terminate(CABACContext *c){
     c->range -= 2;
     if(c->low < c->range<<(CABAC_BITS+1)){
         renorm_cabac_decoder_once(c);
         return 0;
     }else{
         return c->bytestream - c->bytestream_start;
     }
 }
 
 #endif /* AVCODEC_CABAC_FUNCTIONS_H */