tdd.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[email protected]>
 *
 * 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 <[email protected]>
 *
 * \note Includes code and algorithms from the Zapata library.
 */

/*** MODULEINFO
 <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include <time.h>
#include <math.h>
#include <ctype.h>

#include "asterisk/logger.h"
#include "asterisk/ulaw.h"
#include "asterisk/tdd.h"
#include "asterisk/fskmodem.h"
#include "asterisk/utils.h"
#include "ecdisa.h"

struct tdd_state {
 fsk_data fskd;
 char rawdata[256];
 short oldstuff[4096];
 int oldlen;
 int pos;
 int modo;
 int mode;
 int charnum;
};

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','?','+','^','.','/',';','^' };
 int d = 0; /* return 0 if not decodeable */
 if (data < 32) {
 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 = ast_calloc(1, sizeof(*tdd));
 if (tdd) {
#ifdef INTEGER_CALLERID
 tdd->fskd.ispb = 176; /* 45.5 baud */
 /* Set up for 45.5 / 8000 freq *32 to allow ints */
 tdd->fskd.pllispb = (int)((8000 * 32 * 2) / 90);
 tdd->fskd.pllids = tdd->fskd.pllispb / 32;
 tdd->fskd.pllispb2 = tdd->fskd.pllispb / 2;
 tdd->fskd.hdlc = 0; /* Async */
 tdd->fskd.nbit = 5; /* 5 bits */
 tdd->fskd.instop = 1; /* integer rep of 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.xi0 = 0;
 tdd->fskd.state = 0;
 tdd->pos = 0;
 tdd->mode = 0;
 fskmodem_init(&tdd->fskd);
#else
 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;
#endif
 tdd->charnum = 0;
 } 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 = ast_calloc(1, 2 * len + tdd->oldlen);
 short *obuf = buf;
 if (!buf) {
 ast_log(LOG_WARNING, "Out of memory\n");
 return -1;
 }
 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);
 ast_free(obuf);
 return -1;
 }
 buf += (olen - mylen);
 if (res < 0) {
 ast_log(LOG_NOTICE, "fsk_serial failed\n");
 ast_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;
 ast_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)
{
 ast_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 __pas_idx = (short)(rint(8192.0 * (y))); \
 *(buf++) = AST_LIN2MU(__pas_idx); \
 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);

/*! Generate TDD hold tone
 * \param outbuf, buf Result buffer
 * \todo How big should this be?
 */
int tdd_gen_holdtone(unsigned char *buf)
{
 int bytes = 0;
 float scont = 0.0, cr = 1.0, ci=0.0;
 while (scont < tddsb * 10.0) {
 PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1));
 scont += 1.0;
 }
 return bytes;
}

int tdd_generate(struct tdd_state *tdd, unsigned char *buf, const char *str)
{
 int bytes = 0;
 int i,x;
 char c;
 /*! Baudot letters */
 static unsigned char lstr[31] = "\000E\nA SIU\rDRJNFCKTZLWHYPQOBG\000MXV";
 /*! Baudot figures */
 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++) {
 /* Do synch for each 72th character */
 if ( (tdd->charnum++) % 72 == 0)
 PUT_TDD(tdd->mode ? 27 /* FIGS */ : 31 /* LTRS */);

 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;
}