shithub: libvpx

ref: 2a1d89e2782087c240635362b4875cc702e16cf5
dir: /vp8/decoder/treereader.h/

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/*
 *  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.
 */

#ifndef VPX_VP8_DECODER_TREEREADER_H_
#define VPX_VP8_DECODER_TREEREADER_H_

#include "./vpx_config.h"
#include "vp8/common/treecoder.h"
#include "dboolhuff.h"

#ifdef __cplusplus
extern "C" {
#endif

typedef BOOL_DECODER vp8_reader;

#define vp8_read vp8dx_decode_bool
#define vp8_read_literal vp8_decode_value
#define vp8_read_bit(R) vp8_read(R, vp8_prob_half)

/* Intent of tree data structure is to make decoding trivial. */

static INLINE int vp8_treed_read(
    vp8_reader *const r, /* !!! must return a 0 or 1 !!! */
    vp8_tree t, const vp8_prob *const p) {
  vp8_tree_index i = 0;

  while ((i = t[i + vp8_read(r, p[i >> 1])]) > 0) {
  }

  return -i;
}

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // VPX_VP8_DECODER_TREEREADER_H_