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 <math.h>
  36 #include <ctype.h>
  37
  38 #include "asterisk/ulaw.h"
  39 #include "asterisk/tdd.h"
  40 #include "asterisk/fskmodem.h"
  41 #include "ecdisa.h"
  42
  43 struct tdd_state {
  44         fsk_data fskd;
  45         char rawdata[256];
  46         short oldstuff[4096];
  47         int oldlen;
  48         int pos;
  49         int modo;
  50         int mode;
  51         int charnum;
  52 };
  53
  54 static float dr[4], di[4];
  55 static float tddsb = 176.0;  /* 45.5 baud */
  56
  57 #define TDD_SPACE       1800.0          /* 1800 hz for "0" */
  58 #define TDD_MARK        1400.0          /* 1400 hz for "1" */
  59
  60 static int tdd_decode_baudot(struct tdd_state *tdd,unsigned char data)  /* covert baudot into ASCII */
  61 {
  62         static char ltrs[32] = { '<','E','\n','A',' ','S','I','U',
  63                                  '\n','D','R','J','N','F','C','K',
  64                                  'T','Z','L','W','H','Y','P','Q',
  65                                  'O','B','G','^','M','X','V','^' };
  66         static char figs[32] = { '<','3','\n','-',' ','\'','8','7',
  67                                  '\n','$','4','\'',',','!',':','(',
  68                                  '5','\"',')','2','=','6','0','1',
  69                                  '9','?','+','^','.','/',';','^' };
  70         int d = 0;  /* return 0 if not decodeable */
  71         switch (data) {
  72         case 0x1f:
  73                 tdd->modo = 0;
  74                 break;
  75         case 0x1b:
  76                 tdd->modo = 1;
  77                 break;
  78         default:
  79                 if (tdd->modo == 0)
  80                         d = ltrs[data];
  81                 else
  82                         d = figs[data];
  83                 break;
  84         }
  85         return d;
  86 }
  87
  88 void tdd_init(void)
  89 {
  90         /* Initialize stuff for inverse FFT */
  91         dr[0] = cos(TDD_SPACE * 2.0 * M_PI / 8000.0);
  92         di[0] = sin(TDD_SPACE * 2.0 * M_PI / 8000.0);
  93         dr[1] = cos(TDD_MARK * 2.0 * M_PI / 8000.0);
  94         di[1] = sin(TDD_MARK * 2.0 * M_PI / 8000.0);
  95 }
  96
  97 struct tdd_state *tdd_new(void)
  98 {
  99         struct tdd_state *tdd;
 100         tdd = calloc(1, sizeof(*tdd));
 101         if (tdd) {
 102                 tdd->fskd.ispb = 176;        /* 45.5 baud */
 103                 /* Set up for 45.5 / 8000 freq *32 to allow ints */
 104                 tdd->fskd.pllispb  = (int)((8000 * 32 * 2) / 90);
 105                 tdd->fskd.pllids   = tdd->fskd.pllispb / 32;
 106                 tdd->fskd.pllispb2 = tdd->fskd.pllispb / 2;
 107                 tdd->fskd.hdlc = 0;         /* Async */
 108                 tdd->fskd.nbit = 5;         /* 5 bits */
 109                 tdd->fskd.instop = 1;       /* integer rep of 1.5 stop bits */
 110                 tdd->fskd.parity = 0;       /* No parity */
 111                 tdd->fskd.bw=0;             /* Filter 75 Hz */
 112                 tdd->fskd.f_mark_idx = 0;   /* 1400 Hz */
 113                 tdd->fskd.f_space_idx = 1;  /* 1800 Hz */
 114                 tdd->fskd.xi0  = 0;
 115                 tdd->fskd.state = 0;
 116                 tdd->pos = 0;
 117                 tdd->mode = 0;
 118                 tdd->charnum = 0;
 119                 fskmodem_init(&tdd->fskd);
 120         } else
 121                 ast_log(LOG_WARNING, "Out of memory\n");
 122         return tdd;
 123 }
 124
 125 int ast_tdd_gen_ecdisa(unsigned char *outbuf, int len)
 126 {
 127         int pos = 0;
 128         int cnt;
 129         while (len) {
 130                 cnt = len > sizeof(ecdisa) ? sizeof(ecdisa) : len;
 131                 memcpy(outbuf + pos, ecdisa, cnt);
 132                 pos += cnt;
 133                 len -= cnt;
 134         }
 135         return 0;
 136 }
 137
 138 int tdd_feed(struct tdd_state *tdd, unsigned char *ubuf, int len)
 139 {
 140         int mylen = len;
 141         int olen;
 142         int b = 'X';
 143         int res;
 144         int c,x;
 145         short *buf = calloc(1, 2 * len + tdd->oldlen);
 146         short *obuf = buf;
 147         if (!buf) {
 148                 ast_log(LOG_WARNING, "Out of memory\n");
 149                 return -1;
 150         }
 151         memcpy(buf, tdd->oldstuff, tdd->oldlen);
 152         mylen += tdd->oldlen / 2;
 153         for (x = 0; x < len; x++)
 154                 buf[x + tdd->oldlen / 2] = AST_MULAW(ubuf[x]);
 155         c = res = 0;
 156         while (mylen >= 1320) { /* has to have enough to work on */
 157                 olen = mylen;
 158                 res = fsk_serial(&tdd->fskd, buf, &mylen, &b);
 159                 if (mylen < 0) {
 160                         ast_log(LOG_ERROR, "fsk_serial made mylen < 0 (%d) (olen was %d)\n", mylen, olen);
 161                         free(obuf);
 162                         return -1;
 163                 }
 164                 buf += (olen - mylen);
 165                 if (res < 0) {
 166                         ast_log(LOG_NOTICE, "fsk_serial failed\n");
 167                         free(obuf);
 168                         return -1;
 169                 }
 170                 if (res == 1) {
 171                         /* Ignore invalid bytes */
 172                         if (b > 0x7f)
 173                                 continue;
 174                         c = tdd_decode_baudot(tdd, b);
 175                         if ((c < 1) || (c > 126))
 176                                 continue; /* if not valid */
 177                         break;
 178                 }
 179         }
 180         if (mylen) {
 181                 memcpy(tdd->oldstuff, buf, mylen * 2);
 182                 tdd->oldlen = mylen * 2;
 183         } else
 184                 tdd->oldlen = 0;
 185         free(obuf);
 186         if (res) {
 187                 tdd->mode = 2;
 188 /* 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 /*! Generate TDD hold tone */
 260 int tdd_gen_holdtone(unsigned char *buf)
 261 {
 262         int bytes = 0;
 263         float scont = 0.0, cr = 1.0, ci=0.0;
 264         while (scont < tddsb * 10.0) {
 265                 PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1));
 266                 scont += 1.0;
 267         }
 268         return bytes;
 269 }
 270
 271 int tdd_generate(struct tdd_state *tdd, unsigned char *buf, const char *str)
 272 {
 273         int bytes = 0;
 274         int i,x;
 275         char c;
 276         /*! Baudot letters */
 277         static unsigned char lstr[31] = "\000E\nA SIU\rDRJNFCKTZLWHYPQOBG\000MXV";
 278         /*! Baudot figures */
 279         static unsigned char fstr[31] = "\0003\n- \00787\r$4',!:(5\")2\0006019?+\000./;";
 280         /* Initial carriers (real/imaginary) */
 281         float cr = 1.0;
 282         float ci = 0.0;
 283         float scont = 0.0;
 284
 285         for(x = 0; str[x]; x++) {
 286                 /* Do synch for each 72th character */
 287                 if ( (tdd->charnum++) % 72 == 0)
 288                         PUT_TDD(tdd->mode ? 27 /* FIGS */ : 31 /* LTRS */);
 289
 290                 c = toupper(str[x]);
 291 #if     0
 292                 printf("%c",c); fflush(stdout);
 293 #endif
 294                 if (c == 0) { /* send null */
 295                         PUT_TDD(0);
 296                         continue;
 297                 }
 298                 if (c == '\r') { /* send c/r */
 299                         PUT_TDD(8);
 300                         continue;
 301                 }
 302                 if (c == '\n') { /* send c/r and l/f */
 303                         PUT_TDD(8);
 304                         PUT_TDD(2);
 305                         continue;
 306                 }
 307                 if (c == ' ') { /* send space */
 308                         PUT_TDD(4);
 309                         continue;
 310                 }
 311                 for (i = 0; i < 31; i++) {
 312                         if (lstr[i] == c)
 313                                 break;
 314                 }
 315                 if (i < 31) {        /* if we found it */
 316                         if (tdd->mode) { /* if in figs mode, change it */
 317                                 PUT_TDD(31); /* Send LTRS */
 318                                 tdd->mode = 0;
 319                         }
 320                         PUT_TDD(i);
 321                         continue;
 322                 }
 323                 for (i = 0; i < 31; i++) {
 324                         if (fstr[i] == c)
 325                                 break;
 326                 }
 327                 if (i < 31) {             /* if we found it */
 328                         if (tdd->mode != 1) { /* if in ltrs mode, change it */
 329                                 PUT_TDD(27);      /* send FIGS */
 330                                 tdd->mode = 1;
 331                         }
 332                         PUT_TDD(i);           /* send byte */
 333                         continue;
 334                 }
 335         }
 336         return bytes;
 337 }
 338