1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | |
4 | * l1oip_codec.c generic codec using lookup table |
5 | * -> conversion from a-Law to u-Law |
6 | * -> conversion from u-Law to a-Law |
7 | * -> compression by reducing the number of sample resolution to 4 |
8 | * |
9 | * NOTE: It is not compatible with any standard codec like ADPCM. |
10 | * |
11 | * Author Andreas Eversberg (jolly@eversberg.eu) |
12 | * |
13 | |
14 | */ |
15 | |
16 | /* |
17 | |
18 | How the codec works: |
19 | -------------------- |
20 | |
21 | The volume is increased to increase the dynamic range of the audio signal. |
22 | Each sample is converted to a-LAW with only 16 steps of level resolution. |
23 | A pair of two samples are stored in one byte. |
24 | |
25 | The first byte is stored in the upper bits, the second byte is stored in the |
26 | lower bits. |
27 | |
28 | To speed up compression and decompression, two lookup tables are formed: |
29 | |
30 | - 16 bits index for two samples (law encoded) with 8 bit compressed result. |
31 | - 8 bits index for one compressed data with 16 bits decompressed result. |
32 | |
33 | NOTE: The bytes are handled as they are law-encoded. |
34 | |
35 | */ |
36 | |
37 | #include <linux/vmalloc.h> |
38 | #include <linux/mISDNif.h> |
39 | #include <linux/in.h> |
40 | #include "core.h" |
41 | #include "l1oip.h" |
42 | |
43 | /* definitions of codec. don't use calculations, code may run slower. */ |
44 | |
45 | static u8 *table_com; |
46 | static u16 *table_dec; |
47 | |
48 | |
49 | /* alaw -> ulaw */ |
50 | static u8 alaw_to_ulaw[256] = |
51 | { |
52 | 0xab, 0x2b, 0xe3, 0x63, 0x8b, 0x0b, 0xc9, 0x49, |
53 | 0xba, 0x3a, 0xf6, 0x76, 0x9b, 0x1b, 0xd7, 0x57, |
54 | 0xa3, 0x23, 0xdd, 0x5d, 0x83, 0x03, 0xc1, 0x41, |
55 | 0xb2, 0x32, 0xeb, 0x6b, 0x93, 0x13, 0xcf, 0x4f, |
56 | 0xaf, 0x2f, 0xe7, 0x67, 0x8f, 0x0f, 0xcd, 0x4d, |
57 | 0xbe, 0x3e, 0xfe, 0x7e, 0x9f, 0x1f, 0xdb, 0x5b, |
58 | 0xa7, 0x27, 0xdf, 0x5f, 0x87, 0x07, 0xc5, 0x45, |
59 | 0xb6, 0x36, 0xef, 0x6f, 0x97, 0x17, 0xd3, 0x53, |
60 | 0xa9, 0x29, 0xe1, 0x61, 0x89, 0x09, 0xc7, 0x47, |
61 | 0xb8, 0x38, 0xf2, 0x72, 0x99, 0x19, 0xd5, 0x55, |
62 | 0xa1, 0x21, 0xdc, 0x5c, 0x81, 0x01, 0xbf, 0x3f, |
63 | 0xb0, 0x30, 0xe9, 0x69, 0x91, 0x11, 0xce, 0x4e, |
64 | 0xad, 0x2d, 0xe5, 0x65, 0x8d, 0x0d, 0xcb, 0x4b, |
65 | 0xbc, 0x3c, 0xfa, 0x7a, 0x9d, 0x1d, 0xd9, 0x59, |
66 | 0xa5, 0x25, 0xde, 0x5e, 0x85, 0x05, 0xc3, 0x43, |
67 | 0xb4, 0x34, 0xed, 0x6d, 0x95, 0x15, 0xd1, 0x51, |
68 | 0xac, 0x2c, 0xe4, 0x64, 0x8c, 0x0c, 0xca, 0x4a, |
69 | 0xbb, 0x3b, 0xf8, 0x78, 0x9c, 0x1c, 0xd8, 0x58, |
70 | 0xa4, 0x24, 0xde, 0x5e, 0x84, 0x04, 0xc2, 0x42, |
71 | 0xb3, 0x33, 0xec, 0x6c, 0x94, 0x14, 0xd0, 0x50, |
72 | 0xb0, 0x30, 0xe8, 0x68, 0x90, 0x10, 0xce, 0x4e, |
73 | 0xbf, 0x3f, 0xfe, 0x7e, 0xa0, 0x20, 0xdc, 0x5c, |
74 | 0xa8, 0x28, 0xe0, 0x60, 0x88, 0x08, 0xc6, 0x46, |
75 | 0xb7, 0x37, 0xf0, 0x70, 0x98, 0x18, 0xd4, 0x54, |
76 | 0xaa, 0x2a, 0xe2, 0x62, 0x8a, 0x0a, 0xc8, 0x48, |
77 | 0xb9, 0x39, 0xf4, 0x74, 0x9a, 0x1a, 0xd6, 0x56, |
78 | 0xa2, 0x22, 0xdd, 0x5d, 0x82, 0x02, 0xc0, 0x40, |
79 | 0xb1, 0x31, 0xea, 0x6a, 0x92, 0x12, 0xcf, 0x4f, |
80 | 0xae, 0x2e, 0xe6, 0x66, 0x8e, 0x0e, 0xcc, 0x4c, |
81 | 0xbd, 0x3d, 0xfc, 0x7c, 0x9e, 0x1e, 0xda, 0x5a, |
82 | 0xa6, 0x26, 0xdf, 0x5f, 0x86, 0x06, 0xc4, 0x44, |
83 | 0xb5, 0x35, 0xee, 0x6e, 0x96, 0x16, 0xd2, 0x52 |
84 | }; |
85 | |
86 | /* ulaw -> alaw */ |
87 | static u8 ulaw_to_alaw[256] = |
88 | { |
89 | 0xab, 0x55, 0xd5, 0x15, 0x95, 0x75, 0xf5, 0x35, |
90 | 0xb5, 0x45, 0xc5, 0x05, 0x85, 0x65, 0xe5, 0x25, |
91 | 0xa5, 0x5d, 0xdd, 0x1d, 0x9d, 0x7d, 0xfd, 0x3d, |
92 | 0xbd, 0x4d, 0xcd, 0x0d, 0x8d, 0x6d, 0xed, 0x2d, |
93 | 0xad, 0x51, 0xd1, 0x11, 0x91, 0x71, 0xf1, 0x31, |
94 | 0xb1, 0x41, 0xc1, 0x01, 0x81, 0x61, 0xe1, 0x21, |
95 | 0x59, 0xd9, 0x19, 0x99, 0x79, 0xf9, 0x39, 0xb9, |
96 | 0x49, 0xc9, 0x09, 0x89, 0x69, 0xe9, 0x29, 0xa9, |
97 | 0xd7, 0x17, 0x97, 0x77, 0xf7, 0x37, 0xb7, 0x47, |
98 | 0xc7, 0x07, 0x87, 0x67, 0xe7, 0x27, 0xa7, 0xdf, |
99 | 0x9f, 0x7f, 0xff, 0x3f, 0xbf, 0x4f, 0xcf, 0x0f, |
100 | 0x8f, 0x6f, 0xef, 0x2f, 0x53, 0x13, 0x73, 0x33, |
101 | 0xb3, 0x43, 0xc3, 0x03, 0x83, 0x63, 0xe3, 0x23, |
102 | 0xa3, 0x5b, 0xdb, 0x1b, 0x9b, 0x7b, 0xfb, 0x3b, |
103 | 0xbb, 0xbb, 0x4b, 0x4b, 0xcb, 0xcb, 0x0b, 0x0b, |
104 | 0x8b, 0x8b, 0x6b, 0x6b, 0xeb, 0xeb, 0x2b, 0x2b, |
105 | 0xab, 0x54, 0xd4, 0x14, 0x94, 0x74, 0xf4, 0x34, |
106 | 0xb4, 0x44, 0xc4, 0x04, 0x84, 0x64, 0xe4, 0x24, |
107 | 0xa4, 0x5c, 0xdc, 0x1c, 0x9c, 0x7c, 0xfc, 0x3c, |
108 | 0xbc, 0x4c, 0xcc, 0x0c, 0x8c, 0x6c, 0xec, 0x2c, |
109 | 0xac, 0x50, 0xd0, 0x10, 0x90, 0x70, 0xf0, 0x30, |
110 | 0xb0, 0x40, 0xc0, 0x00, 0x80, 0x60, 0xe0, 0x20, |
111 | 0x58, 0xd8, 0x18, 0x98, 0x78, 0xf8, 0x38, 0xb8, |
112 | 0x48, 0xc8, 0x08, 0x88, 0x68, 0xe8, 0x28, 0xa8, |
113 | 0xd6, 0x16, 0x96, 0x76, 0xf6, 0x36, 0xb6, 0x46, |
114 | 0xc6, 0x06, 0x86, 0x66, 0xe6, 0x26, 0xa6, 0xde, |
115 | 0x9e, 0x7e, 0xfe, 0x3e, 0xbe, 0x4e, 0xce, 0x0e, |
116 | 0x8e, 0x6e, 0xee, 0x2e, 0x52, 0x12, 0x72, 0x32, |
117 | 0xb2, 0x42, 0xc2, 0x02, 0x82, 0x62, 0xe2, 0x22, |
118 | 0xa2, 0x5a, 0xda, 0x1a, 0x9a, 0x7a, 0xfa, 0x3a, |
119 | 0xba, 0xba, 0x4a, 0x4a, 0xca, 0xca, 0x0a, 0x0a, |
120 | 0x8a, 0x8a, 0x6a, 0x6a, 0xea, 0xea, 0x2a, 0x2a |
121 | }; |
122 | |
123 | /* alaw -> 4bit compression */ |
124 | static u8 alaw_to_4bit[256] = { |
125 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
126 | 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
127 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
128 | 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
129 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
130 | 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
131 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
132 | 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
133 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
134 | 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
135 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0d, 0x02, |
136 | 0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
137 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
138 | 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
139 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
140 | 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
141 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
142 | 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
143 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
144 | 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
145 | 0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
146 | 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x01, 0x0a, 0x05, |
147 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
148 | 0x0d, 0x02, 0x09, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
149 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
150 | 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
151 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
152 | 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
153 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
154 | 0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04, |
155 | 0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03, |
156 | 0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04, |
157 | }; |
158 | |
159 | /* 4bit -> alaw decompression */ |
160 | static u8 _4bit_to_alaw[16] = { |
161 | 0x5d, 0x51, 0xd9, 0xd7, 0x5f, 0x53, 0xa3, 0x4b, |
162 | 0x2a, 0x3a, 0x22, 0x2e, 0x26, 0x56, 0x20, 0x2c, |
163 | }; |
164 | |
165 | /* ulaw -> 4bit compression */ |
166 | static u8 ulaw_to_4bit[256] = { |
167 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
168 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
169 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
170 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
171 | 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, |
172 | 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, |
173 | 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, |
174 | 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, |
175 | 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, |
176 | 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, |
177 | 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, |
178 | 0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05, |
179 | 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, |
180 | 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, |
181 | 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, |
182 | 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x08, |
183 | 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, |
184 | 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, |
185 | 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, |
186 | 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, |
187 | 0x0f, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, |
188 | 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, |
189 | 0x0e, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, |
190 | 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, |
191 | 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, |
192 | 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0b, 0x0b, |
193 | 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, |
194 | 0x0b, 0x0b, 0x0b, 0x0b, 0x0a, 0x0a, 0x0a, 0x0a, |
195 | 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, |
196 | 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, |
197 | 0x09, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, |
198 | 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, |
199 | }; |
200 | |
201 | /* 4bit -> ulaw decompression */ |
202 | static u8 _4bit_to_ulaw[16] = { |
203 | 0x11, 0x21, 0x31, 0x40, 0x4e, 0x5c, 0x68, 0x71, |
204 | 0xfe, 0xef, 0xe7, 0xdb, 0xcd, 0xbf, 0xaf, 0x9f, |
205 | }; |
206 | |
207 | |
208 | /* |
209 | * Compresses data to the result buffer |
210 | * The result size must be at least half of the input buffer. |
211 | * The number of samples also must be even! |
212 | */ |
213 | int |
214 | l1oip_law_to_4bit(u8 *data, int len, u8 *result, u32 *state) |
215 | { |
216 | int ii, i = 0, o = 0; |
217 | |
218 | if (!len) |
219 | return 0; |
220 | |
221 | /* send saved byte and first input byte */ |
222 | if (*state) { |
223 | *result++ = table_com[(((*state) << 8) & 0xff00) | (*data++)]; |
224 | len--; |
225 | o++; |
226 | } |
227 | |
228 | ii = len >> 1; |
229 | |
230 | while (i < ii) { |
231 | *result++ = table_com[(data[0]<<8) | (data[1])]; |
232 | data += 2; |
233 | i++; |
234 | o++; |
235 | } |
236 | |
237 | /* if len has an odd number, we save byte for next call */ |
238 | if (len & 1) |
239 | *state = 0x100 + *data; |
240 | else |
241 | *state = 0; |
242 | |
243 | return o; |
244 | } |
245 | |
246 | /* Decompress data to the result buffer |
247 | * The result size must be the number of sample in packet. (2 * input data) |
248 | * The number of samples in the result are even! |
249 | */ |
250 | int |
251 | l1oip_4bit_to_law(u8 *data, int len, u8 *result) |
252 | { |
253 | int i = 0; |
254 | u16 r; |
255 | |
256 | while (i < len) { |
257 | r = table_dec[*data++]; |
258 | *result++ = r >> 8; |
259 | *result++ = r; |
260 | i++; |
261 | } |
262 | |
263 | return len << 1; |
264 | } |
265 | |
266 | |
267 | /* |
268 | * law conversion |
269 | */ |
270 | int |
271 | l1oip_alaw_to_ulaw(u8 *data, int len, u8 *result) |
272 | { |
273 | int i = 0; |
274 | |
275 | while (i < len) { |
276 | *result++ = alaw_to_ulaw[*data++]; |
277 | i++; |
278 | } |
279 | |
280 | return len; |
281 | } |
282 | |
283 | int |
284 | l1oip_ulaw_to_alaw(u8 *data, int len, u8 *result) |
285 | { |
286 | int i = 0; |
287 | |
288 | while (i < len) { |
289 | *result++ = ulaw_to_alaw[*data++]; |
290 | i++; |
291 | } |
292 | |
293 | return len; |
294 | } |
295 | |
296 | |
297 | /* |
298 | * generate/free compression and decompression table |
299 | */ |
300 | void |
301 | l1oip_4bit_free(void) |
302 | { |
303 | vfree(addr: table_dec); |
304 | vfree(addr: table_com); |
305 | table_com = NULL; |
306 | table_dec = NULL; |
307 | } |
308 | |
309 | int |
310 | l1oip_4bit_alloc(int ulaw) |
311 | { |
312 | int i1, i2, c, sample; |
313 | |
314 | /* in case, it is called again */ |
315 | if (table_dec) |
316 | return 0; |
317 | |
318 | /* alloc conversion tables */ |
319 | table_com = vzalloc(size: 65536); |
320 | table_dec = vzalloc(size: 512); |
321 | if (!table_com || !table_dec) { |
322 | l1oip_4bit_free(); |
323 | return -ENOMEM; |
324 | } |
325 | /* generate compression table */ |
326 | i1 = 0; |
327 | while (i1 < 256) { |
328 | if (ulaw) |
329 | c = ulaw_to_4bit[i1]; |
330 | else |
331 | c = alaw_to_4bit[i1]; |
332 | i2 = 0; |
333 | while (i2 < 256) { |
334 | table_com[(i1 << 8) | i2] |= (c << 4); |
335 | table_com[(i2 << 8) | i1] |= c; |
336 | i2++; |
337 | } |
338 | i1++; |
339 | } |
340 | |
341 | /* generate decompression table */ |
342 | i1 = 0; |
343 | while (i1 < 16) { |
344 | if (ulaw) |
345 | sample = _4bit_to_ulaw[i1]; |
346 | else |
347 | sample = _4bit_to_alaw[i1]; |
348 | i2 = 0; |
349 | while (i2 < 16) { |
350 | table_dec[(i1 << 4) | i2] |= (sample << 8); |
351 | table_dec[(i2 << 4) | i1] |= sample; |
352 | i2++; |
353 | } |
354 | i1++; |
355 | } |
356 | |
357 | return 0; |
358 | } |
359 | |