1 /* G711adecode.c
2 * A-law G.711 codec
3 *
4 * Wireshark - Network traffic analyzer
5 * By Gerald Combs <gerald@wireshark.org>
6 * Copyright 1998 Gerald Combs
7 *
8 * SPDX-License-Identifier: GPL-2.0-or-later
9 */
10
11 #include "config.h"
12
13 #include <glib.h>
14
15 #include "wsutil/codecs.h"
16 #include "ws_attributes.h"
17
18 static gint16 ulaw_exp_table[256] = {
19 -32124,-31100,-30076,-29052,-28028,-27004,-25980,-24956,
20 -23932,-22908,-21884,-20860,-19836,-18812,-17788,-16764,
21 -15996,-15484,-14972,-14460,-13948,-13436,-12924,-12412,
22 -11900,-11388,-10876,-10364, -9852, -9340, -8828, -8316,
23 -7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140,
24 -5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092,
25 -3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004,
26 -2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980,
27 -1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436,
28 -1372, -1308, -1244, -1180, -1116, -1052, -988, -924,
29 -876, -844, -812, -780, -748, -716, -684, -652,
30 -620, -588, -556, -524, -492, -460, -428, -396,
31 -372, -356, -340, -324, -308, -292, -276, -260,
32 -244, -228, -212, -196, -180, -164, -148, -132,
33 -120, -112, -104, -96, -88, -80, -72, -64,
34 -56, -48, -40, -32, -24, -16, -8, 0,
35 32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956,
36 23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764,
37 15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412,
38 11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316,
39 7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140,
40 5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092,
41 3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004,
42 2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980,
43 1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436,
44 1372, 1308, 1244, 1180, 1116, 1052, 988, 924,
45 876, 844, 812, 780, 748, 716, 684, 652,
46 620, 588, 556, 524, 492, 460, 428, 396,
47 372, 356, 340, 324, 308, 292, 276, 260,
48 244, 228, 212, 196, 180, 164, 148, 132,
49 120, 112, 104, 96, 88, 80, 72, 64,
50 56, 48, 40, 32, 24, 16, 8, 0
51 };
52
53 static gint16 alaw_exp_table[256] = {
54 -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,
55 -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784,
56 -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,
57 -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392,
58 -22016,-20992,-24064,-23040,-17920,-16896,-19968,-18944,
59 -30208,-29184,-32256,-31232,-26112,-25088,-28160,-27136,
60 -11008,-10496,-12032,-11520, -8960, -8448, -9984, -9472,
61 -15104,-14592,-16128,-15616,-13056,-12544,-14080,-13568,
62 -344, -328, -376, -360, -280, -264, -312, -296,
63 -472, -456, -504, -488, -408, -392, -440, -424,
64 -88, -72, -120, -104, -24, -8, -56, -40,
65 -216, -200, -248, -232, -152, -136, -184, -168,
66 -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184,
67 -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696,
68 -688, -656, -752, -720, -560, -528, -624, -592,
69 -944, -912, -1008, -976, -816, -784, -880, -848,
70 5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736,
71 7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784,
72 2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368,
73 3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392,
74 22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944,
75 30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136,
76 11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472,
77 15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568,
78 344, 328, 376, 360, 280, 264, 312, 296,
79 472, 456, 504, 488, 408, 392, 440, 424,
80 88, 72, 120, 104, 24, 8, 56, 40,
81 216, 200, 248, 232, 152, 136, 184, 168,
82 1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184,
83 1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696,
84 688, 656, 752, 720, 560, 528, 624, 592,
85 944, 912, 1008, 976, 816, 784, 880, 848
86 };
87
88 void codec_register_g711(void);
89
90 static void *
codec_g711u_init(void)91 codec_g711u_init(void)
92 {
93 return NULL;
94 }
95
96 static void
codec_g711u_release(void * ctx _U_)97 codec_g711u_release(void *ctx _U_)
98 {
99
100 }
101
102 static unsigned
codec_g711u_get_channels(void * ctx _U_)103 codec_g711u_get_channels(void *ctx _U_)
104 {
105 return 1;
106 }
107
108 static unsigned
codec_g711u_get_frequency(void * ctx _U_)109 codec_g711u_get_frequency(void *ctx _U_)
110 {
111 return 8000;
112 }
113
114 static size_t
codec_g711u_decode(void * ctx _U_,const void * inputBytes,size_t inputBytesSize,void * outputSamples,size_t * outputSamplesSize)115 codec_g711u_decode(void *ctx _U_, const void *inputBytes, size_t inputBytesSize,
116 void *outputSamples, size_t *outputSamplesSize)
117 {
118 const guint8 *dataIn = (const guint8 *) inputBytes;
119 gint16 *dataOut = (gint16 *) outputSamples;
120 size_t i;
121
122 if (!outputSamples || !outputSamplesSize) {
123 return inputBytesSize * 2;
124 }
125
126 for (i = 0; i < inputBytesSize; i++)
127 {
128 dataOut[i] = ulaw_exp_table[dataIn[i]];
129 }
130
131 *outputSamplesSize = inputBytesSize * 2;
132 return inputBytesSize * 2;
133 }
134
135 static void *
codec_g711a_init(void)136 codec_g711a_init(void)
137 {
138 return NULL;
139 }
140
141 static void
codec_g711a_release(void * ctx _U_)142 codec_g711a_release(void *ctx _U_)
143 {
144
145 }
146
147 static unsigned
codec_g711a_get_channels(void * ctx _U_)148 codec_g711a_get_channels(void *ctx _U_)
149 {
150 return 1;
151 }
152
153 static unsigned
codec_g711a_get_frequency(void * ctx _U_)154 codec_g711a_get_frequency(void *ctx _U_)
155 {
156 return 8000;
157 }
158
159 static size_t
codec_g711a_decode(void * ctx _U_,const void * inputBytes,size_t inputBytesSize,void * outputSamples,size_t * outputSamplesSize)160 codec_g711a_decode(void *ctx _U_, const void *inputBytes, size_t inputBytesSize,
161 void *outputSamples, size_t *outputSamplesSize)
162 {
163 const guint8 *dataIn = (const guint8 *) inputBytes;
164 gint16 *dataOut = (gint16 *) outputSamples;
165 size_t i;
166
167 if (!outputSamples || !outputSamplesSize) {
168 return inputBytesSize * 2;
169 }
170
171 for (i = 0; i < inputBytesSize; i++)
172 {
173 dataOut[i] = alaw_exp_table[dataIn[i]];
174 }
175
176 *outputSamplesSize = inputBytesSize * 2;
177 return inputBytesSize * 2;
178 }
179
180 void
codec_register_g711(void)181 codec_register_g711(void)
182 {
183 register_codec("g711U", codec_g711u_init, codec_g711u_release,
184 codec_g711u_get_channels, codec_g711u_get_frequency, codec_g711u_decode);
185 register_codec("g711A", codec_g711a_init, codec_g711a_release,
186 codec_g711a_get_channels, codec_g711a_get_frequency, codec_g711a_decode);
187 }
188
189 /*
190 * Editor modelines - https://www.wireshark.org/tools/modelines.html
191 *
192 * Local variables:
193 * c-basic-offset: 4
194 * tab-width: 8
195 * indent-tabs-mode: nil
196 * End:
197 *
198 * vi: set shiftwidth=4 tabstop=8 expandtab:
199 * :indentSize=4:tabSize=8:noTabs=true:
200 */
201