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/*
* 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/channel.h>
#include <asterisk/file.h>
#include <asterisk/logger.h>
#include <asterisk/sched.h>
#include <asterisk/module.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>
#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;
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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);
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));
}
/* 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);
}
}
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 - 3)) != f->datalen - 3) {
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_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);