aboutsummaryrefslogtreecommitdiffstats
path: root/formats/format_gsm.c
blob: f997af1190e7944422ffb47b3e5c396a1a915c8b (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
/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Save to raw, headerless GSM data.
 * \arg File name extension: gsm
 * \ingroup formats
 */
 
#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/time.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>

#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 "asterisk/endian.h"

#include "msgsm.h"

/* Some Ideas for this code came from makegsme.c by Jeffrey Chilton */

/* Portions of the conversion code are by guido@sienanet.it */

#define	GSM_FRAME_SIZE	33
#define	GSM_SAMPLES	160

/* silent gsm frame */
/* begin binary data: */
char gsm_silence[] = /* 33 */
{0xD8,0x20,0xA2,0xE1,0x5A,0x50,0x00,0x49,0x24,0x92,0x49,0x24,0x50,0x00,0x49
,0x24,0x92,0x49,0x24,0x50,0x00,0x49,0x24,0x92,0x49,0x24,0x50,0x00,0x49,0x24
,0x92,0x49,0x24};
/* end binary data. size = 33 bytes */

static struct ast_frame *gsm_read(struct ast_filestream *s, int *whennext)
{
	int res;

	s->fr.frametype = AST_FRAME_VOICE;
	s->fr.subclass = AST_FORMAT_GSM;
	AST_FRAME_SET_BUFFER(&(s->fr), s->buf, AST_FRIENDLY_OFFSET, GSM_FRAME_SIZE)
	s->fr.mallocd = 0;
	if ((res = fread(s->fr.data, 1, GSM_FRAME_SIZE, s->f)) != GSM_FRAME_SIZE) {
		if (res)
			ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
		return NULL;
	}
	*whennext = s->fr.samples = GSM_SAMPLES;
	return &s->fr;
}

static int gsm_write(struct ast_filestream *fs, struct ast_frame *f)
{
	int res;
	unsigned char gsm[2*GSM_FRAME_SIZE];

	if (f->frametype != AST_FRAME_VOICE) {
		ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
		return -1;
	}
	if (f->subclass != AST_FORMAT_GSM) {
		ast_log(LOG_WARNING, "Asked to write non-GSM frame (%d)!\n", f->subclass);
		return -1;
	}
	if (!(f->datalen % 65)) {
		/* This is in MSGSM format, need to be converted */
		int len=0;
		while(len < f->datalen) {
			conv65(f->data + len, gsm);
			if ((res = fwrite(gsm, 1, 2*GSM_FRAME_SIZE, fs->f)) != 2*GSM_FRAME_SIZE) {
				ast_log(LOG_WARNING, "Bad write (%d/66): %s\n", res, strerror(errno));
				return -1;
			}
			len += 65;
		}
	} else {
		if (f->datalen % GSM_FRAME_SIZE) {
			ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 33\n", f->datalen);
			return -1;
		}
		if ((res = fwrite(f->data, 1, f->datalen, fs->f)) != f->datalen) {
				ast_log(LOG_WARNING, "Bad write (%d/33): %s\n", res, strerror(errno));
				return -1;
		}
	}
	return 0;
}

static int gsm_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
{
	off_t offset=0,min,cur,max,distance;
	
	min = 0;
	cur = ftello(fs->f);
	fseeko(fs->f, 0, SEEK_END);
	max = ftello(fs->f);
	/* have to fudge to frame here, so not fully to sample */
	distance = (sample_offset/GSM_SAMPLES) * GSM_FRAME_SIZE;
	if(whence == SEEK_SET)
		offset = distance;
	else if(whence == SEEK_CUR || whence == SEEK_FORCECUR)
		offset = distance + cur;
	else if(whence == SEEK_END)
		offset = max - distance;
	/* Always protect against seeking past the begining. */
	offset = (offset < min)?min:offset;
	if (whence != SEEK_FORCECUR) {
		offset = (offset > max)?max:offset;
	} else if (offset > max) {
		int i;
		fseeko(fs->f, 0, SEEK_END);
		for (i=0; i< (offset - max) / GSM_FRAME_SIZE; i++) {
			fwrite(gsm_silence, 1, GSM_FRAME_SIZE, fs->f);
		}
	}
	return fseeko(fs->f, offset, SEEK_SET);
}

static int gsm_trunc(struct ast_filestream *fs)
{
	return ftruncate(fileno(fs->f), ftello(fs->f));
}

static off_t gsm_tell(struct ast_filestream *fs)
{
	off_t offset = ftello(fs->f);
	return (offset/GSM_FRAME_SIZE)*GSM_SAMPLES;
}

static const struct ast_format gsm_f = {
	.name = "gsm",
	.exts = "gsm",
	.format = AST_FORMAT_GSM,
	.write = gsm_write,
	.seek =	gsm_seek,
	.trunc = gsm_trunc,
	.tell =	gsm_tell,
	.read =	gsm_read,
	.buf_size = 2*GSM_FRAME_SIZE + AST_FRIENDLY_OFFSET,	/* 2 gsm frames */
};

static int load_module(void)
{
	return ast_format_register(&gsm_f);
}

static int unload_module(void)
{
	return ast_format_unregister(gsm_f.name);
}	

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Raw GSM data");