1/*
2 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11
12#include "boolhuff.h"
13#include "blockd.h"
14
15
16
17#if defined(SECTIONBITS_OUTPUT)
18unsigned __int64 Sectionbits[500];
19
20#endif
21
22#ifdef ENTROPY_STATS
23unsigned int active_section = 0;
24#endif
25
26const unsigned int vp8_prob_cost[256] =
27{
28    2047, 2047, 1791, 1641, 1535, 1452, 1385, 1328, 1279, 1235, 1196, 1161, 1129, 1099, 1072, 1046,
29    1023, 1000,  979,  959,  940,  922,  905,  889,  873,  858,  843,  829,  816,  803,  790,  778,
30    767,  755,  744,  733,  723,  713,  703,  693,  684,  675,  666,  657,  649,  641,  633,  625,
31    617,  609,  602,  594,  587,  580,  573,  567,  560,  553,  547,  541,  534,  528,  522,  516,
32    511,  505,  499,  494,  488,  483,  477,  472,  467,  462,  457,  452,  447,  442,  437,  433,
33    428,  424,  419,  415,  410,  406,  401,  397,  393,  389,  385,  381,  377,  373,  369,  365,
34    361,  357,  353,  349,  346,  342,  338,  335,  331,  328,  324,  321,  317,  314,  311,  307,
35    304,  301,  297,  294,  291,  288,  285,  281,  278,  275,  272,  269,  266,  263,  260,  257,
36    255,  252,  249,  246,  243,  240,  238,  235,  232,  229,  227,  224,  221,  219,  216,  214,
37    211,  208,  206,  203,  201,  198,  196,  194,  191,  189,  186,  184,  181,  179,  177,  174,
38    172,  170,  168,  165,  163,  161,  159,  156,  154,  152,  150,  148,  145,  143,  141,  139,
39    137,  135,  133,  131,  129,  127,  125,  123,  121,  119,  117,  115,  113,  111,  109,  107,
40    105,  103,  101,   99,   97,   95,   93,   92,   90,   88,   86,   84,   82,   81,   79,   77,
41    75,   73,   72,   70,   68,   66,   65,   63,   61,   60,   58,   56,   55,   53,   51,   50,
42    48,   46,   45,   43,   41,   40,   38,   37,   35,   33,   32,   30,   29,   27,   25,   24,
43    22,   21,   19,   18,   16,   15,   13,   12,   10,    9,    7,    6,    4,    3,    1,   1
44};
45
46void vp8_start_encode(BOOL_CODER *br, unsigned char *source)
47{
48
49    br->lowvalue = 0;
50    br->range    = 255;
51    br->value    = 0;
52    br->count    = -24;
53    br->buffer   = source;
54    br->pos      = 0;
55}
56
57void vp8_stop_encode(BOOL_CODER *br)
58{
59    int i;
60
61    for (i = 0; i < 32; i++)
62        vp8_encode_bool(br, 0, 128);
63}
64
65DECLARE_ALIGNED(16, static const unsigned int, norm[256]) =
66{
67    0, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
68    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
69    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
70    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
71    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
72    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
73    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
74    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
75};
76
77void vp8_encode_bool(BOOL_CODER *br, int bit, int probability)
78{
79    unsigned int split;
80    int count = br->count;
81    unsigned int range = br->range;
82    unsigned int lowvalue = br->lowvalue;
83    register unsigned int shift;
84
85#ifdef ENTROPY_STATS
86#if defined(SECTIONBITS_OUTPUT)
87
88    if (bit)
89        Sectionbits[active_section] += vp8_prob_cost[255-probability];
90    else
91        Sectionbits[active_section] += vp8_prob_cost[probability];
92
93#endif
94#endif
95
96    split = 1 + (((range - 1) * probability) >> 8);
97
98    range = split;
99
100    if (bit)
101    {
102        lowvalue += split;
103        range = br->range - split;
104    }
105
106    shift = norm[range];
107
108    range <<= shift;
109    count += shift;
110
111    if (count >= 0)
112    {
113        int offset = shift - count;
114
115        if ((lowvalue << (offset - 1)) & 0x80000000)
116        {
117            int x = br->pos - 1;
118
119            while (x >= 0 && br->buffer[x] == 0xff)
120            {
121                br->buffer[x] = (unsigned char)0;
122                x--;
123            }
124
125            br->buffer[x] += 1;
126        }
127
128        br->buffer[br->pos++] = (lowvalue >> (24 - offset));
129        lowvalue <<= offset;
130        shift = count;
131        lowvalue &= 0xffffff;
132        count -= 8 ;
133    }
134
135    lowvalue <<= shift;
136    br->count = count;
137    br->lowvalue = lowvalue;
138    br->range = range;
139}
140
141void vp8_encode_value(BOOL_CODER *br, int data, int bits)
142{
143    int bit;
144
145    for (bit = bits - 1; bit >= 0; bit--)
146        vp8_encode_bool(br, (1 & (data >> bit)), 0x80);
147
148}
149