main/tdd.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2005, Digium, Inc.
   5  *
   6  * Mark Spencer <markster@digium.com>
   7  *
   8  * Includes code and algorithms from the Zapata library.
   9  *
  10  * See http://www.asterisk.org for more information about
  11  * the Asterisk project. Please do not directly contact
  12  * any of the maintainers of this project for assistance;
  13  * the project provides a web site, mailing lists and IRC
  14  * channels for your use.
  15  *
  16  * This program is free software, distributed under the terms of
  17  * the GNU General Public License Version 2. See the LICENSE file
  18  * at the top of the source tree.
  19  */
  20
  21 /*! \file
  22  *
  23  * \brief TTY/TDD Generation support
  24  *
  25  * \author Mark Spencer <markster@digium.com>
  26  *
  27  * \note Includes code and algorithms from the Zapata library.
  28  */
  29
  30 #include "asterisk.h"
  31
  32 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  33
  34 #include <time.h>
  35 #include <string.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <unistd.h>
  39 #include <math.h>
  40 #include <ctype.h>
  41
  42 #include "asterisk/ulaw.h"
  43 #include "asterisk/tdd.h"
  44 #include "asterisk/logger.h"
  45 #include "asterisk/fskmodem.h"
  46 #include "ecdisa.h"
  47
  48 struct tdd_state {
  49         fsk_data fskd;
  50         char rawdata[256];
  51         short oldstuff[4096];
  52         int oldlen;
  53         int pos;
  54         int modo;
  55         int mode;
  56         int charnum;
  57 };
  58
  59 static float dr[4], di[4];
  60 static float tddsb = 176.0;  /* 45.5 baud */
  61
  62 #define TDD_SPACE       1800.0          /* 1800 hz for "0" */
  63 #define TDD_MARK        1400.0          /* 1400 hz for "1" */
  64
  65 static int tdd_decode_baudot(struct tdd_state *tdd,unsigned char data)  /* covert baudot into ASCII */
  66 {
  67         static char ltrs[32] = { '<','E','\n','A',' ','S','I','U',
  68                                  '\n','D','R','J','N','F','C','K',
  69                                  'T','Z','L','W','H','Y','P','Q',
  70                                  'O','B','G','^','M','X','V','^' };
  71         static char figs[32] = { '<','3','\n','-',' ','\'','8','7',
  72                                  '\n','$','4','\'',',','!',':','(',
  73                                  '5','\"',')','2','=','6','0','1',
  74                                  '9','?','+','^','.','/',';','^' };
  75         int d = 0;  /* return 0 if not decodeable */
  76         switch (data) {
  77         case 0x1f:
  78                 tdd->modo = 0;
  79                 break;
  80         case 0x1b:
  81                 tdd->modo = 1;
  82                 break;
  83         default:
  84                 if (tdd->modo == 0)
  85                         d = ltrs[data];
  86                 else
  87                         d = figs[data];
  88                 break;
  89         }
  90         return d;
  91 }
  92
  93 void tdd_init(void)
  94 {
  95         /* Initialize stuff for inverse FFT */
  96         dr[0] = cos(TDD_SPACE * 2.0 * M_PI / 8000.0);
  97         di[0] = sin(TDD_SPACE * 2.0 * M_PI / 8000.0);
  98         dr[1] = cos(TDD_MARK * 2.0 * M_PI / 8000.0);
  99         di[1] = sin(TDD_MARK * 2.0 * M_PI / 8000.0);
 100 }
 101
 102 struct tdd_state *tdd_new(void)
 103 {
 104         struct tdd_state *tdd;
 105         tdd = calloc(1, sizeof(*tdd));
 106         if (tdd) {
 107                 tdd->fskd.spb = 176;        /* 45.5 baud */
 108                 tdd->fskd.hdlc = 0;         /* Async */
 109                 tdd->fskd.nbit = 5;         /* 5 bits */
 110                 tdd->fskd.nstop = 1.5;      /* 1.5 stop bits */
 111                 tdd->fskd.paridad = 0;      /* No parity */
 112                 tdd->fskd.bw=0;             /* Filter 75 Hz */
 113                 tdd->fskd.f_mark_idx = 0;   /* 1400 Hz */
 114                 tdd->fskd.f_space_idx = 1;  /* 1800 Hz */
 115                 tdd->fskd.pcola = 0;        /* No clue */
 116                 tdd->fskd.cont = 0;         /* Digital PLL reset */
 117                 tdd->fskd.x0 = 0.0;
 118                 tdd->fskd.state = 0;
 119                 tdd->pos = 0;
 120                 tdd->mode = 0;
 121                 tdd->charnum = 0;
 122         } else
 123                 ast_log(LOG_WARNING, "Out of memory\n");
 124         return tdd;
 125 }
 126
 127 int ast_tdd_gen_ecdisa(unsigned char *outbuf, int len)
 128 {
 129         int pos = 0;
 130         int cnt;
 131         while (len) {
 132                 cnt = len > sizeof(ecdisa) ? sizeof(ecdisa) : len;
 133                 memcpy(outbuf + pos, ecdisa, cnt);
 134                 pos += cnt;
 135                 len -= cnt;
 136         }
 137         return 0;
 138 }
 139
 140 int tdd_feed(struct tdd_state *tdd, unsigned char *ubuf, int len)
 141 {
 142         int mylen = len;
 143         int olen;
 144         int b = 'X';
 145         int res;
 146         int c,x;
 147         short *buf = calloc(1, 2 * len + tdd->oldlen);
 148         short *obuf = buf;
 149         if (!buf) {
 150                 ast_log(LOG_WARNING, "Out of memory\n");
 151                 return -1;
 152         }
 153         memcpy(buf, tdd->oldstuff, tdd->oldlen);
 154         mylen += tdd->oldlen/2;
 155         for (x = 0; x < len; x++)
 156                 buf[x + tdd->oldlen / 2] = AST_MULAW(ubuf[x]);
 157         c = res = 0;
 158         while (mylen >= 1320) { /* has to have enough to work on */
 159                 olen = mylen;
 160                 res = fsk_serie(&tdd->fskd, buf, &mylen, &b);
 161                 if (mylen < 0) {
 162                         ast_log(LOG_ERROR, "fsk_serial made mylen < 0 (%d) (olen was %d)\n", mylen, olen);
 163                         free(obuf);
 164                         return -1;
 165                 }
 166                 buf += (olen - mylen);
 167                 if (res < 0) {
 168                         ast_log(LOG_NOTICE, "fsk_serial failed\n");
 169                         free(obuf);
 170                         return -1;
 171                 }
 172                 if (res == 1) {
 173                         /* Ignore invalid bytes */
 174                         if (b > 0x7f)
 175                                 continue;
 176                         c = tdd_decode_baudot(tdd,b);
 177                         if ((c < 1) || (c > 126))
 178                                 continue; /* if not valid */
 179                         break;
 180                 }
 181         }
 182         if (mylen) {
 183                 memcpy(tdd->oldstuff, buf, mylen * 2);
 184                 tdd->oldlen = mylen * 2;
 185         } else
 186                 tdd->oldlen = 0;
 187         free(obuf);
 188         if (res) {
 189                 tdd->mode = 2;
 190 /* put it in mode where it
 191                         reliably puts teleprinter in correct shift mode */
 192                 return(c);
 193         }
 194         return 0;
 195 }
 196
 197 void tdd_free(struct tdd_state *tdd)
 198 {
 199         free(tdd);
 200 }
 201
 202 static inline float tdd_getcarrier(float *cr, float *ci, int bit)
 203 {
 204         /* Move along.  There's nothing to see here... */
 205         float t;
 206         t = *cr * dr[bit] - *ci * di[bit];
 207         *ci = *cr * di[bit] + *ci * dr[bit];
 208         *cr = t;
 209
 210         t = 2.0 - (*cr * *cr + *ci * *ci);
 211         *cr *= t;
 212         *ci *= t;
 213         return *cr;
 214 }
 215
 216 #define PUT_BYTE(a) do { \
 217         *(buf++) = (a); \
 218         bytes++; \
 219 } while(0)
 220
 221 #define PUT_AUDIO_SAMPLE(y) do { \
 222         int index = (short)(rint(8192.0 * (y))); \
 223         *(buf++) = AST_LIN2MU(index); \
 224         bytes++; \
 225 } while(0)
 226
 227 #define PUT_TDD_MARKMS do { \
 228         int x; \
 229         for (x=0;x<8;x++) \
 230                 PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
 231 } while(0)
 232
 233 #define PUT_TDD_BAUD(bit) do { \
 234         while (scont < tddsb) { \
 235                 PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, bit)); \
 236                 scont += 1.0; \
 237         } \
 238         scont -= tddsb; \
 239 } while(0)
 240
 241 #define PUT_TDD_STOP do { \
 242         while (scont < (tddsb * 1.5)) { \
 243                 PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
 244                 scont += 1.0; \
 245         } \
 246         scont -= (tddsb * 1.5); \
 247 } while(0)
 248
 249
 250 #define PUT_TDD(byte) do { \
 251         int z; \
 252         unsigned char b = (byte); \
 253         PUT_TDD_BAUD(0);        /* Start bit */ \
 254         for (z = 0; z < 5; z++) { \
 255                 PUT_TDD_BAUD(b & 1); \
 256                 b >>= 1; \
 257         } \
 258         PUT_TDD_STOP;   /* Stop bit */ \
 259 } while(0);
 260
 261 int tdd_generate(struct tdd_state *tdd, unsigned char *buf, const char *str)
 262 {
 263         int bytes=0;
 264         int i,x;
 265         char    c;
 266         /*! Baudot letters */
 267         static unsigned char lstr[31] = "\000E\nA SIU\rDRJNFCKTZLWHYPQOBG\000MXV";
 268         /*! Baudot figures */
 269         static unsigned char fstr[31] = "\0003\n- \00787\r$4',!:(5\")2\0006019?+\000./;";
 270         /* Initial carriers (real/imaginary) */
 271         float cr = 1.0;
 272         float ci = 0.0;
 273         float scont = 0.0;
 274
 275         for(x = 0; str[x]; x++) {
 276                 /* Do synch for each 72th character */
 277                 if ( (tdd->charnum++) % 72 == 0)
 278                         PUT_TDD(tdd->mode ? 27 /* FIGS */ : 31 /* LTRS */);
 279
 280                 c = toupper(str[x]);
 281 #if     0
 282                 printf("%c",c); fflush(stdout);
 283 #endif
 284                 if (c == 0) { /* send null */
 285                         PUT_TDD(0);
 286                         continue;
 287                 }
 288                 if (c == '\r') { /* send c/r */
 289                         PUT_TDD(8);
 290                         continue;
 291                 }
 292                 if (c == '\n') { /* send c/r and l/f */
 293                         PUT_TDD(8);
 294                         PUT_TDD(2);
 295                         continue;
 296                 }
 297                 if (c == ' ') { /* send space */
 298                         PUT_TDD(4);
 299                         continue;
 300                 }
 301                 for (i = 0; i < 31; i++) {
 302                         if (lstr[i] == c)
 303                                 break;
 304                 }
 305                 if (i < 31) {        /* if we found it */
 306                         if (tdd->mode) { /* if in figs mode, change it */
 307                                 PUT_TDD(31); /* Send LTRS */
 308                                 tdd->mode = 0;
 309                         }
 310                         PUT_TDD(i);
 311                         continue;
 312                 }
 313                 for (i = 0; i < 31; i++) {
 314                         if (fstr[i] == c)
 315                                 break;
 316                 }
 317                 if (i < 31) {             /* if we found it */
 318                         if (tdd->mode != 1) { /* if in ltrs mode, change it */
 319                                 PUT_TDD(27);      /* send FIGS */
 320                                 tdd->mode = 1;
 321                         }
 322                         PUT_TDD(i);           /* send byte */
 323                         continue;
 324                 }
 325         }
 326         return bytes;
 327 }
 328