1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libvpx/vp9/decoder/vp9_dboolhuff.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,93 @@
1.4 +/*
1.5 + * Copyright (c) 2010 The WebM project authors. All Rights Reserved.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license
1.8 + * that can be found in the LICENSE file in the root of the source
1.9 + * tree. An additional intellectual property rights grant can be found
1.10 + * in the file PATENTS. All contributing project authors may
1.11 + * be found in the AUTHORS file in the root of the source tree.
1.12 + */
1.13 +
1.14 +#ifndef VP9_DECODER_VP9_DBOOLHUFF_H_
1.15 +#define VP9_DECODER_VP9_DBOOLHUFF_H_
1.16 +
1.17 +#include <stddef.h>
1.18 +#include <limits.h>
1.19 +
1.20 +#include "./vpx_config.h"
1.21 +#include "vpx_ports/mem.h"
1.22 +#include "vpx/vpx_integer.h"
1.23 +
1.24 +typedef size_t VP9_BD_VALUE;
1.25 +
1.26 +#define BD_VALUE_SIZE ((int)sizeof(VP9_BD_VALUE)*CHAR_BIT)
1.27 +
1.28 +typedef struct {
1.29 + const uint8_t *buffer_end;
1.30 + const uint8_t *buffer;
1.31 + VP9_BD_VALUE value;
1.32 + int count;
1.33 + unsigned int range;
1.34 +} vp9_reader;
1.35 +
1.36 +DECLARE_ALIGNED(16, extern const uint8_t, vp9_norm[256]);
1.37 +
1.38 +int vp9_reader_init(vp9_reader *r, const uint8_t *buffer, size_t size);
1.39 +
1.40 +void vp9_reader_fill(vp9_reader *r);
1.41 +
1.42 +const uint8_t *vp9_reader_find_end(vp9_reader *r);
1.43 +
1.44 +static int vp9_read(vp9_reader *br, int probability) {
1.45 + unsigned int bit = 0;
1.46 + VP9_BD_VALUE value;
1.47 + VP9_BD_VALUE bigsplit;
1.48 + int count;
1.49 + unsigned int range;
1.50 + unsigned int split = ((br->range * probability) + (256 - probability)) >> 8;
1.51 +
1.52 + if (br->count < 0)
1.53 + vp9_reader_fill(br);
1.54 +
1.55 + value = br->value;
1.56 + count = br->count;
1.57 +
1.58 + bigsplit = (VP9_BD_VALUE)split << (BD_VALUE_SIZE - 8);
1.59 +
1.60 + range = split;
1.61 +
1.62 + if (value >= bigsplit) {
1.63 + range = br->range - split;
1.64 + value = value - bigsplit;
1.65 + bit = 1;
1.66 + }
1.67 +
1.68 + {
1.69 + register unsigned int shift = vp9_norm[range];
1.70 + range <<= shift;
1.71 + value <<= shift;
1.72 + count -= shift;
1.73 + }
1.74 + br->value = value;
1.75 + br->count = count;
1.76 + br->range = range;
1.77 +
1.78 + return bit;
1.79 +}
1.80 +
1.81 +static int vp9_read_bit(vp9_reader *r) {
1.82 + return vp9_read(r, 128); // vp9_prob_half
1.83 +}
1.84 +
1.85 +static int vp9_read_literal(vp9_reader *br, int bits) {
1.86 + int z = 0, bit;
1.87 +
1.88 + for (bit = bits - 1; bit >= 0; bit--)
1.89 + z |= vp9_read_bit(br) << bit;
1.90 +
1.91 + return z;
1.92 +}
1.93 +
1.94 +int vp9_reader_has_error(vp9_reader *r);
1.95 +
1.96 +#endif // VP9_DECODER_VP9_DBOOLHUFF_H_
