Wed Jan 8 2020 09:49:51

Asterisk developer's documentation


tdd.c
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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 /*** MODULEINFO
31  <support_level>core</support_level>
32  ***/
33 
34 #include "asterisk.h"
35 
36 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 369001 $")
37 
38 #include <time.h>
39 #include <math.h>
40 #include <ctype.h>
41 
42 #include "asterisk/logger.h"
43 #include "asterisk/ulaw.h"
44 #include "asterisk/tdd.h"
45 #include "asterisk/fskmodem.h"
46 #include "ecdisa.h"
47 
48 struct tdd_state {
50  char rawdata[256];
51  short oldstuff[4096];
52  int oldlen;
53  int pos;
54  int modo;
55  int mode;
56  int charnum;
57 };
58 
59 static float dr[4], di[4];
60 static float tddsb = 176.0; /* 45.5 baud */
61 
62 #define TDD_SPACE 1800.0 /* 1800 hz for "0" */
63 #define TDD_MARK 1400.0 /* 1400 hz for "1" */
64 
65 static int tdd_decode_baudot(struct tdd_state *tdd,unsigned char data) /* covert baudot into ASCII */
66 {
67  static char ltrs[32] = { '<','E','\n','A',' ','S','I','U',
68  '\n','D','R','J','N','F','C','K',
69  'T','Z','L','W','H','Y','P','Q',
70  'O','B','G','^','M','X','V','^' };
71  static char figs[32] = { '<','3','\n','-',' ','\'','8','7',
72  '\n','$','4','\'',',','!',':','(',
73  '5','\"',')','2','=','6','0','1',
74  '9','?','+','^','.','/',';','^' };
75  int d = 0; /* return 0 if not decodeable */
76  if (data < 32) {
77  switch (data) {
78  case 0x1f:
79  tdd->modo = 0;
80  break;
81  case 0x1b:
82  tdd->modo = 1;
83  break;
84  default:
85  if (tdd->modo == 0)
86  d = ltrs[data];
87  else
88  d = figs[data];
89  break;
90  }
91  }
92  return d;
93 }
94 
95 void tdd_init(void)
96 {
97  /* Initialize stuff for inverse FFT */
98  dr[0] = cos(TDD_SPACE * 2.0 * M_PI / 8000.0);
99  di[0] = sin(TDD_SPACE * 2.0 * M_PI / 8000.0);
100  dr[1] = cos(TDD_MARK * 2.0 * M_PI / 8000.0);
101  di[1] = sin(TDD_MARK * 2.0 * M_PI / 8000.0);
102 }
103 
104 struct tdd_state *tdd_new(void)
105 {
106  struct tdd_state *tdd;
107  tdd = calloc(1, sizeof(*tdd));
108  if (tdd) {
109 #ifdef INTEGER_CALLERID
110  tdd->fskd.ispb = 176; /* 45.5 baud */
111  /* Set up for 45.5 / 8000 freq *32 to allow ints */
112  tdd->fskd.pllispb = (int)((8000 * 32 * 2) / 90);
113  tdd->fskd.pllids = tdd->fskd.pllispb / 32;
114  tdd->fskd.pllispb2 = tdd->fskd.pllispb / 2;
115  tdd->fskd.hdlc = 0; /* Async */
116  tdd->fskd.nbit = 5; /* 5 bits */
117  tdd->fskd.instop = 1; /* integer rep of 1.5 stop bits */
118  tdd->fskd.parity = 0; /* No parity */
119  tdd->fskd.bw=0; /* Filter 75 Hz */
120  tdd->fskd.f_mark_idx = 0; /* 1400 Hz */
121  tdd->fskd.f_space_idx = 1; /* 1800 Hz */
122  tdd->fskd.xi0 = 0;
123  tdd->fskd.state = 0;
124  tdd->pos = 0;
125  tdd->mode = 0;
126  fskmodem_init(&tdd->fskd);
127 #else
128  tdd->fskd.spb = 176; /* 45.5 baud */
129  tdd->fskd.hdlc = 0; /* Async */
130  tdd->fskd.nbit = 5; /* 5 bits */
131  tdd->fskd.nstop = 1.5; /* 1.5 stop bits */
132  tdd->fskd.parity = 0; /* No parity */
133  tdd->fskd.bw=0; /* Filter 75 Hz */
134  tdd->fskd.f_mark_idx = 0; /* 1400 Hz */
135  tdd->fskd.f_space_idx = 1; /* 1800 Hz */
136  tdd->fskd.pcola = 0; /* No clue */
137  tdd->fskd.cont = 0; /* Digital PLL reset */
138  tdd->fskd.x0 = 0.0;
139  tdd->fskd.state = 0;
140  tdd->pos = 0;
141  tdd->mode = 2;
142 #endif
143  tdd->charnum = 0;
144  } else
145  ast_log(LOG_WARNING, "Out of memory\n");
146  return tdd;
147 }
148 
149 int ast_tdd_gen_ecdisa(unsigned char *outbuf, int len)
150 {
151  int pos = 0;
152  int cnt;
153  while (len) {
154  cnt = len > sizeof(ecdisa) ? sizeof(ecdisa) : len;
155  memcpy(outbuf + pos, ecdisa, cnt);
156  pos += cnt;
157  len -= cnt;
158  }
159  return 0;
160 }
161 
162 int tdd_feed(struct tdd_state *tdd, unsigned char *ubuf, int len)
163 {
164  int mylen = len;
165  int olen;
166  int b = 'X';
167  int res;
168  int c,x;
169  short *buf = calloc(1, 2 * len + tdd->oldlen);
170  short *obuf = buf;
171  if (!buf) {
172  ast_log(LOG_WARNING, "Out of memory\n");
173  return -1;
174  }
175  memcpy(buf, tdd->oldstuff, tdd->oldlen);
176  mylen += tdd->oldlen / 2;
177  for (x = 0; x < len; x++)
178  buf[x + tdd->oldlen / 2] = AST_MULAW(ubuf[x]);
179  c = res = 0;
180  while (mylen >= 1320) { /* has to have enough to work on */
181  olen = mylen;
182  res = fsk_serial(&tdd->fskd, buf, &mylen, &b);
183  if (mylen < 0) {
184  ast_log(LOG_ERROR, "fsk_serial made mylen < 0 (%d) (olen was %d)\n", mylen, olen);
185  free(obuf);
186  return -1;
187  }
188  buf += (olen - mylen);
189  if (res < 0) {
190  ast_log(LOG_NOTICE, "fsk_serial failed\n");
191  free(obuf);
192  return -1;
193  }
194  if (res == 1) {
195  /* Ignore invalid bytes */
196  if (b > 0x7f)
197  continue;
198  c = tdd_decode_baudot(tdd, b);
199  if ((c < 1) || (c > 126))
200  continue; /* if not valid */
201  break;
202  }
203  }
204  if (mylen) {
205  memcpy(tdd->oldstuff, buf, mylen * 2);
206  tdd->oldlen = mylen * 2;
207  } else
208  tdd->oldlen = 0;
209  free(obuf);
210  if (res) {
211  tdd->mode = 2;
212 /* put it in mode where it
213  reliably puts teleprinter in correct shift mode */
214  return(c);
215  }
216  return 0;
217 }
218 
219 void tdd_free(struct tdd_state *tdd)
220 {
221  free(tdd);
222 }
223 
224 static inline float tdd_getcarrier(float *cr, float *ci, int bit)
225 {
226  /* Move along. There's nothing to see here... */
227  float t;
228  t = *cr * dr[bit] - *ci * di[bit];
229  *ci = *cr * di[bit] + *ci * dr[bit];
230  *cr = t;
231 
232  t = 2.0 - (*cr * *cr + *ci * *ci);
233  *cr *= t;
234  *ci *= t;
235  return *cr;
236 }
237 
238 #define PUT_BYTE(a) do { \
239  *(buf++) = (a); \
240  bytes++; \
241 } while(0)
242 
243 #define PUT_AUDIO_SAMPLE(y) do { \
244  int __pas_idx = (short)(rint(8192.0 * (y))); \
245  *(buf++) = AST_LIN2MU(__pas_idx); \
246  bytes++; \
247 } while(0)
248 
249 #define PUT_TDD_MARKMS do { \
250  int x; \
251  for (x = 0; x < 8; x++) \
252  PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
253 } while(0)
254 
255 #define PUT_TDD_BAUD(bit) do { \
256  while (scont < tddsb) { \
257  PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, bit)); \
258  scont += 1.0; \
259  } \
260  scont -= tddsb; \
261 } while(0)
262 
263 #define PUT_TDD_STOP do { \
264  while (scont < (tddsb * 1.5)) { \
265  PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
266  scont += 1.0; \
267  } \
268  scont -= (tddsb * 1.5); \
269 } while(0)
270 
271 
272 #define PUT_TDD(byte) do { \
273  int z; \
274  unsigned char b = (byte); \
275  PUT_TDD_BAUD(0); /* Start bit */ \
276  for (z = 0; z < 5; z++) { \
277  PUT_TDD_BAUD(b & 1); \
278  b >>= 1; \
279  } \
280  PUT_TDD_STOP; /* Stop bit */ \
281 } while(0);
282 
283 /*! Generate TDD hold tone
284  * \param buf Result buffer
285  * \todo How big should this be??? */
286 int tdd_gen_holdtone(unsigned char *buf)
287 {
288  int bytes = 0;
289  float scont = 0.0, cr = 1.0, ci=0.0;
290  while (scont < tddsb * 10.0) {
291  PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1));
292  scont += 1.0;
293  }
294  return bytes;
295 }
296 
297 int tdd_generate(struct tdd_state *tdd, unsigned char *buf, const char *str)
298 {
299  int bytes = 0;
300  int i,x;
301  char c;
302  /*! Baudot letters */
303  static unsigned char lstr[31] = "\000E\nA SIU\rDRJNFCKTZLWHYPQOBG\000MXV";
304  /*! Baudot figures */
305  static unsigned char fstr[31] = "\0003\n- \00787\r$4',!:(5\")2\0006019?+\000./;";
306  /* Initial carriers (real/imaginary) */
307  float cr = 1.0;
308  float ci = 0.0;
309  float scont = 0.0;
310 
311  for(x = 0; str[x]; x++) {
312  /* Do synch for each 72th character */
313  if ( (tdd->charnum++) % 72 == 0)
314  PUT_TDD(tdd->mode ? 27 /* FIGS */ : 31 /* LTRS */);
315 
316  c = toupper(str[x]);
317 #if 0
318  printf("%c",c); fflush(stdout);
319 #endif
320  if (c == 0) { /* send null */
321  PUT_TDD(0);
322  continue;
323  }
324  if (c == '\r') { /* send c/r */
325  PUT_TDD(8);
326  continue;
327  }
328  if (c == '\n') { /* send c/r and l/f */
329  PUT_TDD(8);
330  PUT_TDD(2);
331  continue;
332  }
333  if (c == ' ') { /* send space */
334  PUT_TDD(4);
335  continue;
336  }
337  for (i = 0; i < 31; i++) {
338  if (lstr[i] == c)
339  break;
340  }
341  if (i < 31) { /* if we found it */
342  if (tdd->mode) { /* if in figs mode, change it */
343  PUT_TDD(31); /* Send LTRS */
344  tdd->mode = 0;
345  }
346  PUT_TDD(i);
347  continue;
348  }
349  for (i = 0; i < 31; i++) {
350  if (fstr[i] == c)
351  break;
352  }
353  if (i < 31) { /* if we found it */
354  if (tdd->mode != 1) { /* if in ltrs mode, change it */
355  PUT_TDD(27); /* send FIGS */
356  tdd->mode = 1;
357  }
358  PUT_TDD(i); /* send byte */
359  continue;
360  }
361  }
362  return bytes;
363 }
364 
static float dr[4]
Definition: tdd.c:59
int oldlen
Definition: tdd.c:52
Asterisk main include file. File version handling, generic pbx functions.
void tdd_init(void)
Definition: tdd.c:95
int charnum
Definition: tdd.c:56
#define LOG_WARNING
Definition: logger.h:144
#define PUT_AUDIO_SAMPLE(y)
Definition: tdd.c:243
int pllids
Definition: fskmodem_int.h:60
int fskmodem_init(fsk_data *fskd)
Definition: fskmodem_int.c:197
const char * str
Definition: app_jack.c:144
#define calloc(a, b)
Definition: astmm.h:79
float cont
#define M_PI
float nstop
int tdd_gen_holdtone(unsigned char *outbuf)
Definition: tdd.c:286
u-Law to Signed linear conversion
int ast_tdd_gen_ecdisa(unsigned char *outbuf, int len)
Definition: tdd.c:149
#define AST_MULAW(a)
Definition: ulaw.h:85
int instop
Definition: fskmodem_int.h:46
#define PUT_TDD(byte)
Definition: tdd.c:272
static float tddsb
Definition: tdd.c:60
static float tdd_getcarrier(float *cr, float *ci, int bit)
Definition: tdd.c:224
static unsigned char ecdisa[80]
Definition: ecdisa.h:3
int modo
Definition: tdd.c:54
#define TDD_SPACE
Definition: tdd.c:62
#define LOG_ERROR
Definition: logger.h:155
int pllispb
Definition: fskmodem_int.h:59
#define free(a)
Definition: astmm.h:94
struct tdd_state * tdd_new(void)
Definition: tdd.c:104
int pllispb2
Definition: fskmodem_int.h:61
TTY/TDD Generation support.
static int len(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t buflen)
void ast_log(int level, const char *file, int line, const char *function, const char *fmt,...)
Used for sending a log message This is the standard logger function. Probably the only way you will i...
Definition: logger.c:1207
static float di[4]
Definition: tdd.c:59
#define LOG_NOTICE
Definition: logger.h:133
static int tdd_decode_baudot(struct tdd_state *tdd, unsigned char data)
Definition: tdd.c:65
Definition: tdd.c:48
int f_space_idx
short oldstuff[4096]
Definition: tdd.c:51
Support for logging to various files, console and syslog Configuration in file logger.conf.
fsk_data fskd
Definition: tdd.c:49
int mode
Definition: tdd.c:55
int f_mark_idx
char rawdata[256]
Definition: tdd.c:50
FSK Modem Support.
int tdd_generate(struct tdd_state *tdd, unsigned char *buf, const char *string)
Definition: tdd.c:297
void tdd_free(struct tdd_state *tdd)
Definition: tdd.c:219
static unsigned int cos
Definition: chan_h323.c:147
int fsk_serial(fsk_data *fskd, short *buffer, int *len, int *outbyte)
#define TDD_MARK
Definition: tdd.c:63
int pos
Definition: tdd.c:53
#define ASTERISK_FILE_VERSION(file, version)
Register/unregister a source code file with the core.
Definition: asterisk.h:180
int tdd_feed(struct tdd_state *tdd, unsigned char *ubuf, int samples)
Definition: tdd.c:162