1/*
2 * exp golomb vlc writing stuff
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 * Copyright (c) 2004 Alex Beregszaszi
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23/**
24 * @file
25 * @brief
26 *     exp golomb vlc writing stuff
27 * @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi
28 */
29
30#ifndef AVCODEC_PUT_GOLOMB_H
31#define AVCODEC_PUT_GOLOMB_H
32
33#include <stdint.h>
34#include "put_bits.h"
35
36extern const uint8_t ff_ue_golomb_len[256];
37
38/**
39 * write unsigned exp golomb code. 2^16 - 2 at most
40 */
41static inline void set_ue_golomb(PutBitContext *pb, int i)
42{
43    av_assert2(i >= 0);
44    av_assert2(i <= 0xFFFE);
45
46    if (i < 256)
47        put_bits(pb, ff_ue_golomb_len[i], i + 1);
48    else {
49        int e = av_log2(i + 1);
50        put_bits(pb, 2 * e + 1, i + 1);
51    }
52}
53
54/**
55 * write unsigned exp golomb code. 2^32-2 at most.
56 */
57static inline void set_ue_golomb_long(PutBitContext *pb, uint32_t i)
58{
59    av_assert2(i <= (UINT32_MAX - 1));
60
61    if (i < 256)
62        put_bits(pb, ff_ue_golomb_len[i], i + 1);
63    else {
64        int e = av_log2(i + 1);
65        put_bits64(pb, 2 * e + 1, i + 1);
66    }
67}
68
69/**
70 * write truncated unsigned exp golomb code.
71 */
72static inline void set_te_golomb(PutBitContext *pb, int i, int range)
73{
74    av_assert2(range >= 1);
75    av_assert2(i <= range);
76
77    if (range == 2)
78        put_bits(pb, 1, i ^ 1);
79    else
80        set_ue_golomb(pb, i);
81}
82
83/**
84 * write signed exp golomb code. 16 bits at most.
85 */
86static inline void set_se_golomb(PutBitContext *pb, int i)
87{
88    i = 2 * i - 1;
89    if (i < 0)
90        i ^= -1;    //FIXME check if gcc does the right thing
91    set_ue_golomb(pb, i);
92}
93
94/**
95 * write unsigned golomb rice code (ffv1).
96 */
97static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit,
98                                 int esc_len)
99{
100    int e;
101
102    av_assert2(i >= 0);
103
104    e = i >> k;
105    if (e < limit)
106        put_bits(pb, e + k + 1, (1 << k) + av_mod_uintp2(i, k));
107    else
108        put_bits(pb, limit + esc_len, i - limit + 1);
109}
110
111/**
112 * write unsigned golomb rice code (jpegls).
113 */
114static inline void set_ur_golomb_jpegls(PutBitContext *pb, int i, int k,
115                                        int limit, int esc_len)
116{
117    int e;
118
119    av_assert2(i >= 0);
120
121    e = (i >> k) + 1;
122    if (e < limit) {
123        while (e > 31) {
124            put_bits(pb, 31, 0);
125            e -= 31;
126        }
127        put_bits(pb, e, 1);
128        if (k)
129            put_sbits(pb, k, i);
130    } else {
131        while (limit > 31) {
132            put_bits(pb, 31, 0);
133            limit -= 31;
134        }
135        put_bits(pb, limit, 1);
136        put_bits(pb, esc_len, i - 1);
137    }
138}
139
140/**
141 * write signed golomb rice code (ffv1).
142 */
143static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit,
144                                 int esc_len)
145{
146    int v;
147
148    v  = -2 * i - 1;
149    v ^= (v >> 31);
150
151    set_ur_golomb(pb, v, k, limit, esc_len);
152}
153
154/**
155 * write signed golomb rice code (flac).
156 */
157static inline void set_sr_golomb_flac(PutBitContext *pb, int i, int k,
158                                      int limit, int esc_len)
159{
160    int v;
161
162    v  = -2 * i - 1;
163    v ^= (v >> 31);
164
165    set_ur_golomb_jpegls(pb, v, k, limit, esc_len);
166}
167
168#endif /* AVCODEC_PUT_GOLOMB_H */
169