347 lines
7.7 KiB
C
Executable File
347 lines
7.7 KiB
C
Executable File
/*
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* Asterisk -- A telephony toolkit for Linux.
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*
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* Flat, binary, ADPCM vox file format.
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*
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* Copyright (C) 1999, Mark Spencer
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*
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* Mark Spencer <markster@linux-support.net>
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License
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*/
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#include <asterisk/lock.h>
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#include <asterisk/channel.h>
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#include <asterisk/file.h>
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#include <asterisk/logger.h>
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#include <asterisk/sched.h>
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#include <asterisk/module.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <stdlib.h>
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#include <sys/time.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <pthread.h>
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#ifdef __linux__
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#include <endian.h>
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#else
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#include <machine/endian.h>
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#endif
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#define BUF_SIZE 80 /* 160 samples */
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struct ast_filestream {
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void *reserved[AST_RESERVED_POINTERS];
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/* This is what a filestream means to us */
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int fd; /* Descriptor */
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struct ast_frame fr; /* Frame information */
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char waste[AST_FRIENDLY_OFFSET]; /* Buffer for sending frames, etc */
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char empty; /* Empty character */
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unsigned char buf[BUF_SIZE + 3]; /* Output Buffer */
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int lasttimeout;
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struct timeval last;
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short signal; /* Signal level (file side) */
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short ssindex; /* Signal ssindex (file side) */
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};
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static ast_mutex_t vox_lock = AST_MUTEX_INITIALIZER;
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static int glistcnt = 0;
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static char *name = "vox";
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static char *desc = "Dialogic VOX (ADPCM) File Format";
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static char *exts = "vox";
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/*
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* Step size index shift table
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*/
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static short indsft[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };
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/*
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* Step size table, where stpsz[i]=floor[16*(11/10)^i]
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*/
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static short stpsz[49] = {
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16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73,
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80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279,
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307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
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1060, 1166, 1282, 1411, 1552
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};
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/*
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* Nibble to bit map
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*/
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static short nbl2bit[16][4] = {
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{1, 0, 0, 0}, {1, 0, 0, 1}, {1, 0, 1, 0}, {1, 0, 1, 1},
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{1, 1, 0, 0}, {1, 1, 0, 1}, {1, 1, 1, 0}, {1, 1, 1, 1},
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{-1, 0, 0, 0}, {-1, 0, 0, 1}, {-1, 0, 1, 0}, {-1, 0, 1, 1},
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{-1, 1, 0, 0}, {-1, 1, 0, 1}, {-1, 1, 1, 0}, {-1, 1, 1, 1}
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};
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/*
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* Decode(encoded)
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* Decodes the encoded nibble from the adpcm file.
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*
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* Results:
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* Returns the encoded difference.
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*
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* Side effects:
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* Sets the index to the step size table for the next encode.
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*/
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static inline short
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decode (unsigned char encoded, short *ssindex)
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{
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short diff, step;
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step = stpsz[*ssindex];
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diff = nbl2bit[encoded][0] * (step * nbl2bit[encoded][1] +
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(step >> 1) * nbl2bit[encoded][2] +
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(step >> 2) * nbl2bit[encoded][3] +
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(step >> 3));
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*ssindex = *ssindex + indsft[(encoded & 7)];
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if (*ssindex < 0)
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*ssindex = 0;
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else if (*ssindex > 48)
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*ssindex = 48;
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return (diff);
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}
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/*
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* Adpcm
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* Takes a signed linear signal and encodes it as ADPCM
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* For more information see http://support.dialogic.com/appnotes/adpcm.pdf
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*
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* Results:
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* Foo.
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*
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* Side effects:
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* signal gets updated with each pass.
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*/
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static inline unsigned char
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adpcm (short csig, short *ssindex, short *signal)
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{
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short diff, step;
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unsigned char encoded;
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step = stpsz[*ssindex];
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/*
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* Clip csig if too large or too small
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*/
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csig >>= 4;
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diff = csig - *signal;
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if (diff < 0)
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{
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encoded = 8;
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diff = -diff;
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}
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else
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encoded = 0;
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if (diff >= step)
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{
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encoded |= 4;
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diff -= step;
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}
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step >>= 1;
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if (diff >= step)
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{
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encoded |= 2;
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diff -= step;
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}
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step >>= 1;
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if (diff >= step)
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encoded |= 1;
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*signal += decode (encoded, ssindex);
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return (encoded);
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}
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static struct ast_filestream *vox_open(int fd)
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{
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/* We don't have any header to read or anything really, but
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if we did, it would go here. We also might want to check
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and be sure it's a valid file. */
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struct ast_filestream *tmp;
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if ((tmp = malloc(sizeof(struct ast_filestream)))) {
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memset(tmp, 0, sizeof(struct ast_filestream));
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if (ast_mutex_lock(&vox_lock)) {
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ast_log(LOG_WARNING, "Unable to lock vox list\n");
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free(tmp);
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return NULL;
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}
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tmp->fd = fd;
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tmp->fr.data = tmp->buf;
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tmp->fr.frametype = AST_FRAME_VOICE;
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tmp->fr.subclass = AST_FORMAT_ADPCM;
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/* datalen will vary for each frame */
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tmp->fr.src = name;
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tmp->fr.mallocd = 0;
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tmp->lasttimeout = -1;
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glistcnt++;
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ast_mutex_unlock(&vox_lock);
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ast_update_use_count();
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}
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return tmp;
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}
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static struct ast_filestream *vox_rewrite(int fd, char *comment)
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{
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/* We don't have any header to read or anything really, but
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if we did, it would go here. We also might want to check
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and be sure it's a valid file. */
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struct ast_filestream *tmp;
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if ((tmp = malloc(sizeof(struct ast_filestream)))) {
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memset(tmp, 0, sizeof(struct ast_filestream));
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if (ast_mutex_lock(&vox_lock)) {
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ast_log(LOG_WARNING, "Unable to lock vox list\n");
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free(tmp);
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return NULL;
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}
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tmp->fd = fd;
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glistcnt++;
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ast_mutex_unlock(&vox_lock);
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ast_update_use_count();
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} else
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ast_log(LOG_WARNING, "Out of memory\n");
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return tmp;
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}
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static void vox_close(struct ast_filestream *s)
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{
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if (ast_mutex_lock(&vox_lock)) {
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ast_log(LOG_WARNING, "Unable to lock vox list\n");
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return;
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}
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glistcnt--;
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ast_mutex_unlock(&vox_lock);
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ast_update_use_count();
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close(s->fd);
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free(s);
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s = NULL;
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}
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static struct ast_frame *vox_read(struct ast_filestream *s, int *whennext)
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{
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int res;
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int x;
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/* Send a frame from the file to the appropriate channel */
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s->fr.frametype = AST_FRAME_VOICE;
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s->fr.subclass = AST_FORMAT_ADPCM;
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s->fr.offset = AST_FRIENDLY_OFFSET;
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s->fr.mallocd = 0;
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s->fr.data = s->buf;
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if ((res = read(s->fd, s->buf + 3, BUF_SIZE)) < 1) {
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if (res)
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ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
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return NULL;
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}
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/* Store index, then signal */
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s->buf[0] = s->ssindex & 0xff;
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s->buf[1] = (s->signal >> 8) & 0xff;
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s->buf[2] = s->signal & 0xff;
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/* Do the decoder to be sure we get the right stuff in the signal and index fields. */
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for (x=3;x<res+3;x++) {
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s->signal += decode(s->buf[x] >> 4, &s->ssindex);
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s->signal += decode(s->buf[x] & 0xf, &s->ssindex);
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}
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s->fr.samples = res * 2;
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s->fr.datalen = res + 3;
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*whennext = s->fr.samples;
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return &s->fr;
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}
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static int vox_write(struct ast_filestream *fs, struct ast_frame *f)
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{
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int res;
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if (f->frametype != AST_FRAME_VOICE) {
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ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
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return -1;
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}
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if (f->subclass != AST_FORMAT_ADPCM) {
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ast_log(LOG_WARNING, "Asked to write non-ADPCM frame (%d)!\n", f->subclass);
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return -1;
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}
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if (f->datalen < 3) {
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ast_log(LOG_WARNING, "Invalid frame of data (< 3 bytes long) from %s\n", f->src);
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return -1;
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}
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if ((res = write(fs->fd, f->data + 3, f->datalen - 3)) != f->datalen - 3) {
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ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
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return -1;
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}
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return 0;
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}
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static char *vox_getcomment(struct ast_filestream *s)
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{
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return NULL;
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}
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static int vox_seek(struct ast_filestream *fs, long sample_offset, int whence)
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{
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return -1;
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}
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static int vox_trunc(struct ast_filestream *fs)
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{
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return -1;
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}
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static long vox_tell(struct ast_filestream *fs)
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{
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return -1;
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}
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int load_module()
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{
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return ast_format_register(name, exts, AST_FORMAT_ADPCM,
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vox_open,
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vox_rewrite,
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vox_write,
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vox_seek,
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vox_trunc,
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vox_tell,
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vox_read,
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vox_close,
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vox_getcomment);
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}
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int unload_module()
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{
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return ast_format_unregister(name);
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}
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int usecount()
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{
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int res;
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if (ast_mutex_lock(&vox_lock)) {
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ast_log(LOG_WARNING, "Unable to lock vox list\n");
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return -1;
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}
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res = glistcnt;
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ast_mutex_unlock(&vox_lock);
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return res;
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}
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char *description()
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{
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return desc;
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}
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char *key()
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{
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return ASTERISK_GPL_KEY;
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}
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