vp9_boolhuff.h

/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */


/****************************************************************************
*
*   Module Title :     vp9_boolhuff.h
*
*   Description  :     Bool Coder header file.
*
****************************************************************************/
#ifndef VP9_ENCODER_VP9_BOOLHUFF_H_
#define VP9_ENCODER_VP9_BOOLHUFF_H_

#include "vpx_ports/mem.h"

typedef struct {
  unsigned int lowvalue;
  unsigned int range;
  unsigned int value;
  int count;
  unsigned int pos;
  uint8_t *buffer;

  // Variables used to track bit costs without outputing to the bitstream
  unsigned int  measure_cost;
  unsigned long bit_counter;
} vp9_writer;

extern const unsigned int vp9_prob_cost[256];

void vp9_start_encode(vp9_writer *bc, uint8_t *buffer);
void vp9_stop_encode(vp9_writer *bc);

DECLARE_ALIGNED(16, extern const unsigned char, vp9_norm[256]);

static void vp9_write(vp9_writer *br, int bit, int probability) {
  unsigned int split;
  int count = br->count;
  unsigned int range = br->range;
  unsigned int lowvalue = br->lowvalue;
  register unsigned int shift;

#ifdef ENTROPY_STATS
#if defined(SECTIONBITS_OUTPUT)

  if (bit)
    Sectionbits[active_section] += vp9_prob_cost[255 - probability];
  else
    Sectionbits[active_section] += vp9_prob_cost[probability];

#endif
#endif

  split = 1 + (((range - 1) * probability) >> 8);

  range = split;

  if (bit) {
    lowvalue += split;
    range = br->range - split;
  }