asterisk/formats/format_gsm.c

204 lines
5.5 KiB
C
Raw Normal View History

2023-05-25 18:45:57 +00:00
/*
* 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
*/
/*** MODULEINFO
<support_level>core</support_level>
***/
#include "asterisk.h"
#include "asterisk/mod_format.h"
#include "asterisk/module.h"
#include "asterisk/endian.h"
#include "asterisk/format_cache.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: */
static const 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)
{
size_t res;
AST_FRAME_SET_BUFFER(&(s->fr), s->buf, AST_FRIENDLY_OFFSET, GSM_FRAME_SIZE);
if ((res = fread(s->fr.data.ptr, 1, GSM_FRAME_SIZE, s->f)) != GSM_FRAME_SIZE) {
if (res) {
ast_log(LOG_WARNING, "Short read of %s data (expected %d bytes, read %zu): %s\n",
ast_format_get_name(s->fr.subclass.format), GSM_FRAME_SIZE, 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->datalen % 65)) {
/* This is in MSGSM format, need to be converted */
int len=0;
while(len < f->datalen) {
conv65(f->data.ptr + 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.ptr, 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 = 0, cur, max, distance;
if ((cur = ftello(fs->f)) < 0) {
ast_log(AST_LOG_WARNING, "Unable to determine current position in g719 filestream %p: %s\n", fs, strerror(errno));
return -1;
}
if (fseeko(fs->f, 0, SEEK_END) < 0) {
ast_log(AST_LOG_WARNING, "Unable to seek to end of g719 filestream %p: %s\n", fs, strerror(errno));
return -1;
}
if ((max = ftello(fs->f)) < 0) {
ast_log(AST_LOG_WARNING, "Unable to determine max position in g719 filestream %p: %s\n", fs, strerror(errno));
return -1;
}
/* 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++) {
if (fwrite(gsm_silence, 1, GSM_FRAME_SIZE, fs->f) != GSM_FRAME_SIZE) {
ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
}
}
}
return fseeko(fs->f, offset, SEEK_SET);
}
static int gsm_trunc(struct ast_filestream *fs)
{
int fd;
off_t cur;
if ((fd = fileno(fs->f)) < 0) {
ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for gsm filestream %p: %s\n", fs, strerror(errno));
return -1;
}
if ((cur = ftello(fs->f)) < 0) {
ast_log(AST_LOG_WARNING, "Unable to determine current position in gsm filestream %p: %s\n", fs, strerror(errno));
return -1;
}
/* Truncate file to current length */
return ftruncate(fd, cur);
}
static off_t gsm_tell(struct ast_filestream *fs)
{
off_t offset = ftello(fs->f);
if (offset < 0) {
ast_log(AST_LOG_WARNING, "Unable to determine offset for gsm filestream %p: %s\n", fs, strerror(errno));
return 0;
}
return (offset / GSM_FRAME_SIZE) * GSM_SAMPLES;
}
static struct ast_format_def gsm_f = {
.name = "gsm",
.exts = "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)
{
gsm_f.format = ast_format_gsm;
if (ast_format_def_register(&gsm_f))
return AST_MODULE_LOAD_DECLINE;
return AST_MODULE_LOAD_SUCCESS;
}
static int unload_module(void)
{
return ast_format_def_unregister(gsm_f.name);
}
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Raw GSM data",
.support_level = AST_MODULE_SUPPORT_CORE,
.load = load_module,
.unload = unload_module,
.load_pri = AST_MODPRI_APP_DEPEND
);