tdd.c

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/*
 * 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.
 */
 
/*** 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
 * \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;
}