aboutsummaryrefslogtreecommitdiffstats
path: root/formats/format_vox.c
blob: 851f1fb81030b158ecc789543d6176b19ea6f48a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
/*
 * Asterisk -- A telephony toolkit for Linux.
 *
 * Flat, binary, ADPCM vox file format.
 * 
 * Copyright (C) 1999, Mark Spencer
 *
 * Mark Spencer <markster@linux-support.net>
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License
 */
 
#include <asterisk/lock.h>
#include <asterisk/channel.h>
#include <asterisk/file.h>
#include <asterisk/logger.h>
#include <asterisk/sched.h>
#include <asterisk/module.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/time.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <pthread.h>
#ifdef __linux__
#include <endian.h>
#else
#include <machine/endian.h>
#endif

#define BUF_SIZE 80		/* 160 samples */

struct ast_filestream {
	void *reserved[AST_RESERVED_POINTERS];
	/* This is what a filestream means to us */
	int fd; /* Descriptor */
	struct ast_frame fr;				/* Frame information */
	char waste[AST_FRIENDLY_OFFSET];	/* Buffer for sending frames, etc */
	char empty;							/* Empty character */
	unsigned char buf[BUF_SIZE + 3];				/* Output Buffer */
	int lasttimeout;
	struct timeval last;
	short signal;						/* Signal level (file side) */
	short ssindex;						/* Signal ssindex (file side) */
};


static ast_mutex_t vox_lock = AST_MUTEX_INITIALIZER;
static int glistcnt = 0;

static char *name = "vox";
static char *desc = "Dialogic VOX (ADPCM) File Format";
static char *exts = "vox";

/*
 * Step size index shift table 
 */

static short indsft[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };

/*
 * Step size table, where stpsz[i]=floor[16*(11/10)^i]
 */

static short stpsz[49] = {
  16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73,
  80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279,
  307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
  1060, 1166, 1282, 1411, 1552
};

/* 
 * Nibble to bit map
 */

static short nbl2bit[16][4] = {
  {1, 0, 0, 0}, {1, 0, 0, 1}, {1, 0, 1, 0}, {1, 0, 1, 1},
  {1, 1, 0, 0}, {1, 1, 0, 1}, {1, 1, 1, 0}, {1, 1, 1, 1},
  {-1, 0, 0, 0}, {-1, 0, 0, 1}, {-1, 0, 1, 0}, {-1, 0, 1, 1},
  {-1, 1, 0, 0}, {-1, 1, 0, 1}, {-1, 1, 1, 0}, {-1, 1, 1, 1}
};

/*
 * Decode(encoded)
 *  Decodes the encoded nibble from the adpcm file.
 *
 * Results:
 *  Returns the encoded difference.
 *
 * Side effects:
 *  Sets the index to the step size table for the next encode.
 */

static inline short
decode (unsigned char encoded, short *ssindex)
{
  short diff, step;
  step = stpsz[*ssindex];
  diff = nbl2bit[encoded][0] * (step * nbl2bit[encoded][1] +
				(step >> 1) * nbl2bit[encoded][2] +
				(step >> 2) * nbl2bit[encoded][3] +
				(step >> 3));
  *ssindex = *ssindex + indsft[(encoded & 7)];
  if (*ssindex < 0)
    *ssindex = 0;
  else if (*ssindex > 48)
    *ssindex = 48;
  return (diff);
}

/*
 * Adpcm
 *  Takes a signed linear signal and encodes it as ADPCM
 *  For more information see http://support.dialogic.com/appnotes/adpcm.pdf
 *
 * Results:
 *  Foo.
 *
 * Side effects:
 *  signal gets updated with each pass.
 */

static inline unsigned char
adpcm (short csig, short *ssindex, short *signal)
{
  short diff, step;
  unsigned char encoded;
  step = stpsz[*ssindex];
  /* 
   * Clip csig if too large or too small
   */
   
  csig >>= 4;

  diff = csig - *signal;
  
  if (diff < 0)
    {
      encoded = 8;
      diff = -diff;
    }
  else
    encoded = 0;
  if (diff >= step)
    {
      encoded |= 4;
      diff -= step;
    }
  step >>= 1;
  if (diff >= step)
    {
      encoded |= 2;
      diff -= step;
    }
  step >>= 1;
  if (diff >= step)
    encoded |= 1;
    
  *signal += decode (encoded, ssindex);
  return (encoded);
}

static struct ast_filestream *vox_open(int fd)
{
	/* We don't have any header to read or anything really, but
	   if we did, it would go here.  We also might want to check
	   and be sure it's a valid file.  */
	struct ast_filestream *tmp;
	if ((tmp = malloc(sizeof(struct ast_filestream)))) {
		memset(tmp, 0, sizeof(struct ast_filestream));
		if (ast_mutex_lock(&vox_lock)) {
			ast_log(LOG_WARNING, "Unable to lock vox list\n");
			free(tmp);
			return NULL;
		}
		tmp->fd = fd;
		tmp->fr.data = tmp->buf;
		tmp->fr.frametype = AST_FRAME_VOICE;
		tmp->fr.subclass = AST_FORMAT_ADPCM;
		/* datalen will vary for each frame */
		tmp->fr.src = name;
		tmp->fr.mallocd = 0;
		tmp->lasttimeout = -1;
		glistcnt++;
		ast_mutex_unlock(&vox_lock);
		ast_update_use_count();
	}
	return tmp;
}

static struct ast_filestream *vox_rewrite(int fd, char *comment)
{
	/* We don't have any header to read or anything really, but
	   if we did, it would go here.  We also might want to check
	   and be sure it's a valid file.  */
	struct ast_filestream *tmp;
	if ((tmp = malloc(sizeof(struct ast_filestream)))) {
		memset(tmp, 0, sizeof(struct ast_filestream));
		if (ast_mutex_lock(&vox_lock)) {
			ast_log(LOG_WARNING, "Unable to lock vox list\n");
			free(tmp);
			return NULL;
		}
		tmp->fd = fd;
		glistcnt++;
		ast_mutex_unlock(&vox_lock);
		ast_update_use_count();
	} else
		ast_log(LOG_WARNING, "Out of memory\n");
	return tmp;
}

static void vox_close(struct ast_filestream *s)
{
	if (ast_mutex_lock(&vox_lock)) {
		ast_log(LOG_WARNING, "Unable to lock vox list\n");
		return;
	}
	glistcnt--;
	ast_mutex_unlock(&vox_lock);
	ast_update_use_count();
	close(s->fd);
	free(s);
	s = NULL;
}

static struct ast_frame *vox_read(struct ast_filestream *s, int *whennext)
{
	int res;
	int x;
	/* Send a frame from the file to the appropriate channel */

	s->fr.frametype = AST_FRAME_VOICE;
	s->fr.subclass = AST_FORMAT_ADPCM;
	s->fr.offset = AST_FRIENDLY_OFFSET;
	s->fr.mallocd = 0;
	s->fr.data = s->buf;
	if ((res = read(s->fd, s->buf + 3, BUF_SIZE)) < 1) {
		if (res)
			ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
		return NULL;
	}
	/* Store index, then signal */
	s->buf[0] = s->ssindex & 0xff;
	s->buf[1] = (s->signal >> 8) & 0xff;
	s->buf[2] = s->signal & 0xff;
	/* Do the decoder to be sure we get the right stuff in the signal and index fields. */
	for (x=3;x<res+3;x++) {
		s->signal += decode(s->buf[x] >> 4, &s->ssindex);
		s->signal += decode(s->buf[x] & 0xf, &s->ssindex);
	}
	s->fr.samples = res * 2;
	s->fr.datalen = res + 3;
	*whennext = s->fr.samples;
	return &s->fr;
}

static int vox_write(struct ast_filestream *fs, struct ast_frame *f)
{
	int res;
	if (f->frametype != AST_FRAME_VOICE) {
		ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
		return -1;
	}
	if (f->subclass != AST_FORMAT_ADPCM) {
		ast_log(LOG_WARNING, "Asked to write non-ADPCM frame (%d)!\n", f->subclass);
		return -1;
	}
	if (f->datalen < 3) {
		ast_log(LOG_WARNING, "Invalid frame of data (< 3 bytes long) from %s\n", f->src);
		return -1;
	}
	if ((res = write(fs->fd, f->data + 3, f->datalen)) != f->datalen) {
			ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
			return -1;
	}
	return 0;
}

static char *vox_getcomment(struct ast_filestream *s)
{
	return NULL;
}

static int vox_seek(struct ast_filestream *fs, long sample_offset, int whence)
{
	return -1;
}

static int vox_trunc(struct ast_filestream *fs)
{
	return -1;
}

static long vox_tell(struct ast_filestream *fs)
{
	return -1;
}

int load_module()
{
	return ast_format_register(name, exts, AST_FORMAT_ADPCM,
								vox_open,
								vox_rewrite,
								vox_write,
								vox_seek,
								vox_trunc,
								vox_tell,
								vox_read,
								vox_close,
								vox_getcomment);
								
								
}

int unload_module()
{
	return ast_format_unregister(name);
}	

int usecount()
{
	int res;
	if (ast_mutex_lock(&vox_lock)) {
		ast_log(LOG_WARNING, "Unable to lock vox list\n");
		return -1;
	}
	res = glistcnt;
	ast_mutex_unlock(&vox_lock);
	return res;
}

char *description()
{
	return desc;
}


char *key()
{
	return ASTERISK_GPL_KEY;
}