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 };
  57
  58 static float dr[4], di[4];
  59 static float tddsb = 176.0;  /* 45.5 baud */
  60
  61 #define TDD_SPACE       1800.0          /* 1800 hz for "0" */
  62 #define TDD_MARK        1400.0          /* 1400 hz for "1" */
  63
  64 static int tdd_decode_baudot(struct tdd_state *tdd,unsigned char data)  /* covert baudot into ASCII */
  65 {
  66         static char ltrs[32] = { '<','E','\n','A',' ','S','I','U',
  67                                  '\n','D','R','J','N','F','C','K',
  68                                  'T','Z','L','W','H','Y','P','Q',
  69                                  'O','B','G','^','M','X','V','^' };
  70         static char figs[32] = { '<','3','\n','-',' ',',','8','7',
  71                                  '\n','$','4','\'',',','·',':','(',
  72                                  '5','+',')','2','·','6','0','1',
  73                                  '9','7','·','^','.','/','=','^' };
  74         int d = 0;  /* return 0 if not decodeable */
  75         switch (data) {
  76         case 0x1f:
  77                 tdd->modo = 0;
  78                 break;
  79         case 0x1b:
  80                 tdd->modo = 1;
  81                 break;
  82         default:
  83                 if (tdd->modo == 0)
  84                         d = ltrs[data];
  85                 else
  86                         d = figs[data];
  87                 break;
  88         }
  89         return d;
  90 }
  91
  92 void tdd_init(void)
  93 {
  94         /* Initialize stuff for inverse FFT */
  95         dr[0] = cos(TDD_SPACE * 2.0 * M_PI / 8000.0);
  96         di[0] = sin(TDD_SPACE * 2.0 * M_PI / 8000.0);
  97         dr[1] = cos(TDD_MARK * 2.0 * M_PI / 8000.0);
  98         di[1] = sin(TDD_MARK * 2.0 * M_PI / 8000.0);
  99 }
 100
 101 struct tdd_state *tdd_new(void)
 102 {
 103         struct tdd_state *tdd;
 104         tdd = malloc(sizeof(struct tdd_state));
 105         if (tdd) {
 106                 memset(tdd, 0, sizeof(struct tdd_state));
 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 = 2;
 121         } else
 122                 ast_log(LOG_WARNING, "Out of memory\n");
 123         return tdd;
 124 }
 125
 126 int ast_tdd_gen_ecdisa(unsigned char *outbuf, int len)
 127 {
 128         int pos = 0;
 129         int cnt;
 130         while (len) {
 131                 cnt = len > sizeof(ecdisa) ? sizeof(ecdisa) : len;
 132                 memcpy(outbuf + pos, ecdisa, cnt);
 133                 pos += cnt;
 134                 len -= cnt;
 135         }
 136         return 0;
 137 }
 138
 139 int tdd_feed(struct tdd_state *tdd, unsigned char *ubuf, int len)
 140 {
 141         int mylen = len;
 142         int olen;
 143         int b = 'X';
 144         int res;
 145         int c,x;
 146         short *buf = malloc(2 * len + tdd->oldlen);
 147         short *obuf = buf;
 148         if (!buf) {
 149                 ast_log(LOG_WARNING, "Out of memory\n");
 150                 return -1;
 151         }
 152         memset(buf, 0, 2 * len + tdd->oldlen);
 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_serie 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_serie 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)) continue; /* if not valid */
 178                         break;
 179                 }
 180         }
 181         if (mylen) {
 182                 memcpy(tdd->oldstuff, buf, mylen * 2);
 183                 tdd->oldlen = mylen * 2;
 184         } else
 185                 tdd->oldlen = 0;
 186         free(obuf);
 187         if (res) {
 188                 tdd->mode = 2; /* put it in mode where it
 189                         reliably puts teleprinter in correct shift mode */
 190                 return(c);
 191         }
 192         return 0;
 193 }
 194
 195 void tdd_free(struct tdd_state *tdd)
 196 {
 197         free(tdd);
 198 }
 199
 200 static inline float tdd_getcarrier(float *cr, float *ci, int bit)
 201 {
 202         /* Move along.  There's nothing to see here... */
 203         float t;
 204         t = *cr * dr[bit] - *ci * di[bit];
 205         *ci = *cr * di[bit] + *ci * dr[bit];
 206         *cr = t;
 207
 208         t = 2.0 - (*cr * *cr + *ci * *ci);
 209         *cr *= t;
 210         *ci *= t;
 211         return *cr;
 212 }
 213
 214 #define PUT_BYTE(a) do { \
 215         *(buf++) = (a); \
 216         bytes++; \
 217 } while(0)
 218
 219 #define PUT_AUDIO_SAMPLE(y) do { \
 220         int index = (short)(rint(8192.0 * (y))); \
 221         *(buf++) = AST_LIN2MU(index); \
 222         bytes++; \
 223 } while(0)
 224
 225 #define PUT_TDD_MARKMS do { \
 226         int x; \
 227         for (x=0;x<8;x++) \
 228                 PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
 229 } while(0)
 230
 231 #define PUT_TDD_BAUD(bit) do { \
 232         while(scont < tddsb) { \
 233                 PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, bit)); \
 234                 scont += 1.0; \
 235         } \
 236         scont -= tddsb; \
 237 } while(0)
 238
 239 #define PUT_TDD_STOP do { \
 240         while(scont < (tddsb * 1.5)) { \
 241                 PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
 242                 scont += 1.0; \
 243         } \
 244         scont -= (tddsb * 1.5); \
 245 } while(0)
 246
 247
 248 #define PUT_TDD(byte) do { \
 249         int z; \
 250         unsigned char b = (byte); \
 251         PUT_TDD_BAUD(0);        /* Start bit */ \
 252         for (z = 0; z < 5; z++) { \
 253                 PUT_TDD_BAUD(b & 1); \
 254                 b >>= 1; \
 255         } \
 256         PUT_TDD_STOP;   /* Stop bit */ \
 257 } while(0);
 258
 259 int tdd_generate(struct tdd_state *tdd, unsigned char *buf, const char *str)
 260 {
 261         int bytes=0;
 262         int i,x;
 263         char    c;
 264         static unsigned char lstr[31] = "\000E\nA SIU\rDRJNFCKTZLWHYPQOBG\000MXV";
 265         static unsigned char fstr[31] = "\0003\n- \00787\r$4',!:(5\")2\0006019?&\000./;";
 266         /* Initial carriers (real/imaginary) */
 267         float cr = 1.0;
 268         float ci = 0.0;
 269         float scont = 0.0;
 270
 271         for(x = 0; str[x]; x++) {
 272                 c = toupper(str[x]);
 273 #if     0
 274                 printf("%c",c); fflush(stdout);
 275 #endif
 276                 if (c == 0) { /* send null */
 277                         PUT_TDD(0);
 278                         continue;
 279                 }
 280                 if (c == '\r') { /* send c/r */
 281                         PUT_TDD(8);
 282                         continue;
 283                 }
 284                 if (c == '\n') { /* send c/r and l/f */
 285                         PUT_TDD(8);
 286                         PUT_TDD(2);
 287                         continue;
 288                 }
 289                 if (c == ' ') { /* send space */
 290                         PUT_TDD(4);
 291                         continue;
 292                 }
 293                 for (i = 0; i < 31; i++) {
 294                         if (lstr[i] == c)
 295                                 break;
 296                 }
 297                 if (i < 31) {        /* if we found it */
 298                         if (tdd->mode) { /* if in figs mode, change it */
 299                                 PUT_TDD(31); /* Send LTRS */
 300                                 tdd->mode = 0;
 301                         }
 302                         PUT_TDD(i);
 303                         continue;
 304                 }
 305                 for (i = 0; i < 31; i++) {
 306                         if (fstr[i] == c)
 307                                 break;
 308                 }
 309                 if (i < 31) {             /* if we found it */
 310                         if (tdd->mode != 1) { /* if in ltrs mode, change it */
 311                                 PUT_TDD(27);      /* send FIGS */
 312                                 tdd->mode = 1;
 313                         }
 314                         PUT_TDD(i);           /* send byte */
 315                         continue;
 316                 }
 317         }
 318         return bytes;
 319 }
 320