1/*
2 * Header file for hardcoded PCM tables
3 *
4 * Copyright (c) 2010 Reimar D��ffinger <Reimar.Doeffinger@gmx.de>
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#ifndef PCM_TABLEGEN_H
24#define PCM_TABLEGEN_H
25
26#include <stdint.h>
27#include "../libavutil/attributes.h"
28
29/* from g711.c by SUN microsystems (unrestricted use) */
30
31#define         SIGN_BIT        (0x80)      /* Sign bit for a A-law byte. */
32#define         QUANT_MASK      (0xf)       /* Quantization field mask. */
33#define         NSEGS           (8)         /* Number of A-law segments. */
34#define         SEG_SHIFT       (4)         /* Left shift for segment number. */
35#define         SEG_MASK        (0x70)      /* Segment field mask. */
36
37#define         BIAS            (0x84)      /* Bias for linear code. */
38
39/*
40 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
41 *
42 */
43static av_cold int alaw2linear(unsigned char a_val)
44{
45        int t;
46        int seg;
47
48        a_val ^= 0x55;
49
50        t = a_val & QUANT_MASK;
51        seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
52        if(seg) t= (t + t + 1 + 32) << (seg + 2);
53        else    t= (t + t + 1     ) << 3;
54
55        return (a_val & SIGN_BIT) ? t : -t;
56}
57
58static av_cold int ulaw2linear(unsigned char u_val)
59{
60        int t;
61
62        /* Complement to obtain normal u-law value. */
63        u_val = ~u_val;
64
65        /*
66         * Extract and bias the quantization bits. Then
67         * shift up by the segment number and subtract out the bias.
68         */
69        t = ((u_val & QUANT_MASK) << 3) + BIAS;
70        t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
71
72        return (u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS);
73}
74
75#if CONFIG_HARDCODED_TABLES
76#define pcm_alaw_tableinit()
77#define pcm_ulaw_tableinit()
78#include "libavcodec/pcm_tables.h"
79#else
80/* 16384 entries per table */
81static uint8_t linear_to_alaw[16384];
82static uint8_t linear_to_ulaw[16384];
83
84static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw,
85                             int (*xlaw2linear)(unsigned char),
86                             int mask)
87{
88    int i, j, v, v1, v2;
89
90    j = 0;
91    for(i=0;i<128;i++) {
92        if (i != 127) {
93            v1 = xlaw2linear(i ^ mask);
94            v2 = xlaw2linear((i + 1) ^ mask);
95            v = (v1 + v2 + 4) >> 3;
96        } else {
97            v = 8192;
98        }
99        for(;j<v;j++) {
100            linear_to_xlaw[8192 + j] = (i ^ mask);
101            if (j > 0)
102                linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
103        }
104    }
105    linear_to_xlaw[0] = linear_to_xlaw[1];
106}
107
108static void pcm_alaw_tableinit(void)
109{
110    build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
111}
112
113static void pcm_ulaw_tableinit(void)
114{
115    build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
116}
117#endif /* CONFIG_HARDCODED_TABLES */
118
119#endif /* PCM_TABLEGEN_H */
120