Files
asterisk/main/tdd.c
Jason Parker 87f81679ee Expand on r48273 (from issue 8506), to translate more of the fskmodem stuff to English.
r48273 dealt with the comments and such, this deals with the code itself.
(This couldn't have been easily done if it weren't for 48273 - thanks again for that merbanan)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@48276 65c4cc65-6c06-0410-ace0-fbb531ad65f3
2006-12-05 20:15:37 +00:00

322 lines
7.2 KiB
C

/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 1999 - 2005, Digium, Inc.
*
* Mark Spencer <markster@digium.com>
*
* Includes code and algorithms from the Zapata library.
*
* 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 TTY/TDD Generation support
*
* \author Mark Spencer <markster@digium.com>
*
* \note Includes code and algorithms from the Zapata library.
*/
#include "asterisk.h"
ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include <time.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>
#include <ctype.h>
#include "asterisk/ulaw.h"
#include "asterisk/tdd.h"
#include "asterisk/logger.h"
#include "asterisk/fskmodem.h"
#include "ecdisa.h"
struct tdd_state {
fsk_data fskd;
char rawdata[256];
short oldstuff[4096];
int oldlen;
int pos;
int modo;
int mode;
};
static float dr[4], di[4];
static float tddsb = 176.0; /* 45.5 baud */
#define TDD_SPACE 1800.0 /* 1800 hz for "0" */
#define TDD_MARK 1400.0 /* 1400 hz for "1" */
static int tdd_decode_baudot(struct tdd_state *tdd,unsigned char data) /* covert baudot into ASCII */
{
static char ltrs[32] = { '<','E','\n','A',' ','S','I','U',
'\n','D','R','J','N','F','C','K',
'T','Z','L','W','H','Y','P','Q',
'O','B','G','^','M','X','V','^' };
static char figs[32] = { '<','3','\n','-',' ',',','8','7',
'\n','$','4','\'',',','·',':','(',
'5','+',')','2','·','6','0','1',
'9','7','·','^','.','/','=','^' };
int d = 0; /* return 0 if not decodeable */
switch (data) {
case 0x1f:
tdd->modo = 0;
break;
case 0x1b:
tdd->modo = 1;
break;
default:
if (tdd->modo == 0)
d = ltrs[data];
else
d = figs[data];
break;
}
return d;
}
void tdd_init(void)
{
/* Initialize stuff for inverse FFT */
dr[0] = cos(TDD_SPACE * 2.0 * M_PI / 8000.0);
di[0] = sin(TDD_SPACE * 2.0 * M_PI / 8000.0);
dr[1] = cos(TDD_MARK * 2.0 * M_PI / 8000.0);
di[1] = sin(TDD_MARK * 2.0 * M_PI / 8000.0);
}
struct tdd_state *tdd_new(void)
{
struct tdd_state *tdd;
tdd = malloc(sizeof(struct tdd_state));
if (tdd) {
memset(tdd, 0, sizeof(struct tdd_state));
tdd->fskd.spb = 176; /* 45.5 baud */
tdd->fskd.hdlc = 0; /* Async */
tdd->fskd.nbit = 5; /* 5 bits */
tdd->fskd.nstop = 1.5; /* 1.5 stop bits */
tdd->fskd.parity = 0; /* No parity */
tdd->fskd.bw=0; /* Filter 75 Hz */
tdd->fskd.f_mark_idx = 0; /* 1400 Hz */
tdd->fskd.f_space_idx = 1; /* 1800 Hz */
tdd->fskd.pcola = 0; /* No clue */
tdd->fskd.cont = 0; /* Digital PLL reset */
tdd->fskd.x0 = 0.0;
tdd->fskd.state = 0;
tdd->pos = 0;
tdd->mode = 2;
} else
ast_log(LOG_WARNING, "Out of memory\n");
return tdd;
}
int ast_tdd_gen_ecdisa(unsigned char *outbuf, int len)
{
int pos = 0;
int cnt;
while (len) {
cnt = len > sizeof(ecdisa) ? sizeof(ecdisa) : len;
memcpy(outbuf + pos, ecdisa, cnt);
pos += cnt;
len -= cnt;
}
return 0;
}
int tdd_feed(struct tdd_state *tdd, unsigned char *ubuf, int len)
{
int mylen = len;
int olen;
int b = 'X';
int res;
int c,x;
short *buf = malloc(2 * len + tdd->oldlen);
short *obuf = buf;
if (!buf) {
ast_log(LOG_WARNING, "Out of memory\n");
return -1;
}
memset(buf, 0, 2 * len + tdd->oldlen);
memcpy(buf, tdd->oldstuff, tdd->oldlen);
mylen += tdd->oldlen/2;
for (x = 0; x < len; x++)
buf[x + tdd->oldlen / 2] = AST_MULAW(ubuf[x]);
c = res = 0;
while (mylen >= 1320) { /* has to have enough to work on */
olen = mylen;
res = fsk_serial(&tdd->fskd, buf, &mylen, &b);
if (mylen < 0) {
ast_log(LOG_ERROR, "fsk_serial made mylen < 0 (%d) (olen was %d)\n", mylen, olen);
free(obuf);
return -1;
}
buf += (olen - mylen);
if (res < 0) {
ast_log(LOG_NOTICE, "fsk_serial failed\n");
free(obuf);
return -1;
}
if (res == 1) {
/* Ignore invalid bytes */
if (b > 0x7f)
continue;
c = tdd_decode_baudot(tdd,b);
if ((c < 1) || (c > 126))
continue; /* if not valid */
break;
}
}
if (mylen) {
memcpy(tdd->oldstuff, buf, mylen * 2);
tdd->oldlen = mylen * 2;
} else
tdd->oldlen = 0;
free(obuf);
if (res) {
tdd->mode = 2; /* put it in mode where it
reliably puts teleprinter in correct shift mode */
return(c);
}
return 0;
}
void tdd_free(struct tdd_state *tdd)
{
free(tdd);
}
static inline float tdd_getcarrier(float *cr, float *ci, int bit)
{
/* Move along. There's nothing to see here... */
float t;
t = *cr * dr[bit] - *ci * di[bit];
*ci = *cr * di[bit] + *ci * dr[bit];
*cr = t;
t = 2.0 - (*cr * *cr + *ci * *ci);
*cr *= t;
*ci *= t;
return *cr;
}
#define PUT_BYTE(a) do { \
*(buf++) = (a); \
bytes++; \
} while(0)
#define PUT_AUDIO_SAMPLE(y) do { \
int index = (short)(rint(8192.0 * (y))); \
*(buf++) = AST_LIN2MU(index); \
bytes++; \
} while(0)
#define PUT_TDD_MARKMS do { \
int x; \
for (x=0;x<8;x++) \
PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
} while(0)
#define PUT_TDD_BAUD(bit) do { \
while(scont < tddsb) { \
PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, bit)); \
scont += 1.0; \
} \
scont -= tddsb; \
} while(0)
#define PUT_TDD_STOP do { \
while(scont < (tddsb * 1.5)) { \
PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
scont += 1.0; \
} \
scont -= (tddsb * 1.5); \
} while(0)
#define PUT_TDD(byte) do { \
int z; \
unsigned char b = (byte); \
PUT_TDD_BAUD(0); /* Start bit */ \
for (z = 0; z < 5; z++) { \
PUT_TDD_BAUD(b & 1); \
b >>= 1; \
} \
PUT_TDD_STOP; /* Stop bit */ \
} while(0);
int tdd_generate(struct tdd_state *tdd, unsigned char *buf, const char *str)
{
int bytes=0;
int i,x;
char c;
static unsigned char lstr[31] = "\000E\nA SIU\rDRJNFCKTZLWHYPQOBG\000MXV";
static unsigned char fstr[31] = "\0003\n- \00787\r$4',!:(5\")2\0006019?&\000./;";
/* Initial carriers (real/imaginary) */
float cr = 1.0;
float ci = 0.0;
float scont = 0.0;
for(x = 0; str[x]; x++) {
c = toupper(str[x]);
#if 0
printf("%c",c); fflush(stdout);
#endif
if (c == 0) { /* send null */
PUT_TDD(0);
continue;
}
if (c == '\r') { /* send c/r */
PUT_TDD(8);
continue;
}
if (c == '\n') { /* send c/r and l/f */
PUT_TDD(8);
PUT_TDD(2);
continue;
}
if (c == ' ') { /* send space */
PUT_TDD(4);
continue;
}
for (i = 0; i < 31; i++) {
if (lstr[i] == c)
break;
}
if (i < 31) { /* if we found it */
if (tdd->mode) { /* if in figs mode, change it */
PUT_TDD(31); /* Send LTRS */
tdd->mode = 0;
}
PUT_TDD(i);
continue;
}
for (i = 0; i < 31; i++) {
if (fstr[i] == c)
break;
}
if (i < 31) { /* if we found it */
if (tdd->mode != 1) { /* if in ltrs mode, change it */
PUT_TDD(27); /* send FIGS */
tdd->mode = 1;
}
PUT_TDD(i); /* send byte */
continue;
}
}
return bytes;
}