Sat Aug 6 00:40:06 2011

Asterisk developer's documentation


tdd.c File Reference

TTY/TDD Generation support. More...

#include "asterisk.h"
#include <time.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>
#include <ctype.h>
#include "asterisk/ulaw.h"
#include "asterisk/tdd.h"
#include "asterisk/logger.h"
#include "asterisk/fskmodem.h"
#include "ecdisa.h"

Go to the source code of this file.

Data Structures

struct  tdd_state

Defines

#define PUT_AUDIO_SAMPLE(y)
#define PUT_BYTE(a)
#define PUT_TDD(byte)
#define PUT_TDD_BAUD(bit)
#define PUT_TDD_MARKMS
#define PUT_TDD_STOP
#define TDD_MARK   1400.0
#define TDD_SPACE   1800.0

Functions

int ast_tdd_gen_ecdisa (unsigned char *outbuf, int len)
static int tdd_decode_baudot (struct tdd_state *tdd, unsigned char data)
int tdd_feed (struct tdd_state *tdd, unsigned char *ubuf, int len)
void tdd_free (struct tdd_state *tdd)
int tdd_generate (struct tdd_state *tdd, unsigned char *buf, const char *str)
static float tdd_getcarrier (float *cr, float *ci, int bit)
void tdd_init (void)
tdd_statetdd_new (void)

Variables

static float di [4]
static float dr [4]
static float tddsb = 176.0


Detailed Description

TTY/TDD Generation support.

Author:
Mark Spencer <markster@digium.com>
Note:
Includes code and algorithms from the Zapata library.

Definition in file tdd.c.


Define Documentation

#define PUT_AUDIO_SAMPLE (  ) 

Value:

do { \
   int index = (short)(rint(8192.0 * (y))); \
   *(buf++) = AST_LIN2MU(index); \
   bytes++; \
} while(0)

Definition at line 221 of file tdd.c.

#define PUT_BYTE (  ) 

Value:

do { \
   *(buf++) = (a); \
   bytes++; \
} while(0)

Definition at line 216 of file tdd.c.

Referenced by ast_callerid_vmwi_generate(), and callerid_generate().

#define PUT_TDD ( byte   ) 

Definition at line 250 of file tdd.c.

Referenced by tdd_generate().

#define PUT_TDD_BAUD ( bit   ) 

Definition at line 233 of file tdd.c.

#define PUT_TDD_MARKMS

Value:

do { \
   int x; \
   for (x=0;x<8;x++) \
      PUT_AUDIO_SAMPLE(tdd_getcarrier(&cr, &ci, 1)); \
} while(0)

Definition at line 227 of file tdd.c.

#define PUT_TDD_STOP

Definition at line 241 of file tdd.c.

#define TDD_MARK   1400.0

Definition at line 63 of file tdd.c.

Referenced by tdd_init().

#define TDD_SPACE   1800.0

Definition at line 62 of file tdd.c.

Referenced by tdd_init().


Function Documentation

int ast_tdd_gen_ecdisa ( unsigned char *  outbuf,
int  len 
)

Parameters:
outbuf This is the buffer to receive the tone data
len This is the length (in samples) of the tone data to generate Returns 0 if no error, and -1 if error.

Definition at line 127 of file tdd.c.

References ecdisa, and tdd_state::pos.

Referenced by dahdi_setoption().

00128 {
00129    int pos = 0;
00130    int cnt;
00131    while (len) {
00132       cnt = len > sizeof(ecdisa) ? sizeof(ecdisa) : len;
00133       memcpy(outbuf + pos, ecdisa, cnt);
00134       pos += cnt;
00135       len -= cnt;
00136    }
00137    return 0;
00138 }

static int tdd_decode_baudot ( struct tdd_state tdd,
unsigned char  data 
) [static]

Definition at line 65 of file tdd.c.

References tdd_state::modo.

Referenced by tdd_feed().

00066 {
00067    static char ltrs[32] = { '<','E','\n','A',' ','S','I','U',
00068                             '\n','D','R','J','N','F','C','K',
00069                             'T','Z','L','W','H','Y','P','Q',
00070                             'O','B','G','^','M','X','V','^' };
00071    static char figs[32] = { '<','3','\n','-',' ','\'','8','7',
00072                             '\n','$','4','\'',',','!',':','(',
00073                             '5','\"',')','2','=','6','0','1',
00074                             '9','?','+','^','.','/',';','^' };
00075    int d = 0;  /* return 0 if not decodeable */
00076    switch (data) {
00077    case 0x1f:
00078       tdd->modo = 0;
00079       break;
00080    case 0x1b:
00081       tdd->modo = 1;
00082       break;
00083    default:
00084       if (tdd->modo == 0)
00085          d = ltrs[data];
00086       else
00087          d = figs[data];
00088       break;
00089    }
00090    return d;
00091 }

int tdd_feed ( struct tdd_state tdd,
unsigned char *  ubuf,
int  samples 
)

Parameters:
tdd Which state machine to act upon
ubuf containing your samples
samples number of samples contained within the buffer.
Send received audio to the TDD demodulator. Returns -1 on error, 0 for "needs more samples", and > 0 (the character) if reception of a character is complete.

Definition at line 140 of file tdd.c.

References ast_log(), AST_MULAW, calloc, free, fsk_serie(), tdd_state::fskd, LOG_ERROR, LOG_NOTICE, LOG_WARNING, tdd_state::mode, tdd_state::oldlen, tdd_state::oldstuff, and tdd_decode_baudot().

00141 {
00142    int mylen = len;
00143    int olen;
00144    int b = 'X';
00145    int res;
00146    int c,x;
00147    short *buf = calloc(1, 2 * len + tdd->oldlen);
00148    short *obuf = buf;
00149    if (!buf) {
00150       ast_log(LOG_WARNING, "Out of memory\n");
00151       return -1;
00152    }
00153    memcpy(buf, tdd->oldstuff, tdd->oldlen);
00154    mylen += tdd->oldlen/2;
00155    for (x = 0; x < len; x++) 
00156       buf[x + tdd->oldlen / 2] = AST_MULAW(ubuf[x]);
00157    c = res = 0;
00158    while (mylen >= 1320) { /* has to have enough to work on */
00159       olen = mylen;
00160       res = fsk_serie(&tdd->fskd, buf, &mylen, &b);
00161       if (mylen < 0) {
00162          ast_log(LOG_ERROR, "fsk_serial made mylen < 0 (%d) (olen was %d)\n", mylen, olen);
00163          free(obuf);
00164          return -1;
00165       }
00166       buf += (olen - mylen);
00167       if (res < 0) {
00168          ast_log(LOG_NOTICE, "fsk_serial failed\n");
00169          free(obuf);
00170          return -1;
00171       }
00172       if (res == 1) {
00173          /* Ignore invalid bytes */
00174          if (b > 0x7f)
00175             continue;
00176          c = tdd_decode_baudot(tdd,b);
00177          if ((c < 1) || (c > 126))
00178             continue; /* if not valid */
00179          break;
00180       }
00181    }
00182    if (mylen) {
00183       memcpy(tdd->oldstuff, buf, mylen * 2);
00184       tdd->oldlen = mylen * 2;
00185    } else
00186       tdd->oldlen = 0;
00187    free(obuf);
00188    if (res) {
00189       tdd->mode = 2; 
00190 /* put it in mode where it
00191          reliably puts teleprinter in correct shift mode */
00192       return(c);
00193    }
00194    return 0;
00195 }

void tdd_free ( struct tdd_state tdd  ) 

Parameters:
tdd This is the tdd_state state machine to free This function frees tdd_state tdd.

Definition at line 197 of file tdd.c.

References free.

Referenced by dahdi_setoption().

00198 {
00199    free(tdd);
00200 }

int tdd_generate ( struct tdd_state tdd,
unsigned char *  buf,
const char *  string 
)

Parameters:
tdd tdd structure
buf Buffer to use. This needs to be large enough to accomodate all the generated samples.
string This is the string to send. This function creates a stream of TDD data in ulaw format. It returns the size (in bytes) of the data (if it returns a size of 0, there is probably an error)

Baudot letters

Baudot figures

Definition at line 261 of file tdd.c.

References tdd_state::charnum, tdd_state::mode, and PUT_TDD.

Referenced by dahdi_sendtext().

00262 {
00263    int bytes=0;
00264    int i,x;
00265    char  c;
00266    /*! Baudot letters */
00267    static unsigned char lstr[31] = "\000E\nA SIU\rDRJNFCKTZLWHYPQOBG\000MXV";
00268    /*! Baudot figures */
00269    static unsigned char fstr[31] = "\0003\n- \00787\r$4',!:(5\")2\0006019?+\000./;";
00270    /* Initial carriers (real/imaginary) */
00271    float cr = 1.0;
00272    float ci = 0.0;
00273    float scont = 0.0;
00274 
00275    for(x = 0; str[x]; x++) {
00276       /* Do synch for each 72th character */
00277       if ( (tdd->charnum++) % 72 == 0) 
00278          PUT_TDD(tdd->mode ? 27 /* FIGS */ : 31 /* LTRS */);
00279 
00280       c = toupper(str[x]);
00281 #if   0
00282       printf("%c",c); fflush(stdout);
00283 #endif
00284       if (c == 0) { /* send null */
00285          PUT_TDD(0);
00286          continue;
00287       }
00288       if (c == '\r') { /* send c/r */
00289          PUT_TDD(8);
00290          continue;
00291       }
00292       if (c == '\n') { /* send c/r and l/f */
00293          PUT_TDD(8);
00294          PUT_TDD(2);
00295          continue;
00296       }
00297       if (c == ' ') { /* send space */
00298          PUT_TDD(4);
00299          continue;
00300       }
00301       for (i = 0; i < 31; i++) {
00302          if (lstr[i] == c)
00303             break;
00304       }
00305       if (i < 31) {        /* if we found it */
00306          if (tdd->mode) { /* if in figs mode, change it */
00307             PUT_TDD(31); /* Send LTRS */
00308             tdd->mode = 0;
00309          }
00310          PUT_TDD(i);
00311          continue;
00312       }
00313       for (i = 0; i < 31; i++) {
00314          if (fstr[i] == c)
00315             break;
00316       }
00317       if (i < 31) {             /* if we found it */
00318          if (tdd->mode != 1) { /* if in ltrs mode, change it */
00319             PUT_TDD(27);      /* send FIGS */
00320             tdd->mode = 1;
00321          }
00322          PUT_TDD(i);           /* send byte */
00323          continue;
00324       }
00325    }
00326    return bytes;
00327 }

static float tdd_getcarrier ( float *  cr,
float *  ci,
int  bit 
) [inline, static]

Definition at line 202 of file tdd.c.

References t.

00203 {
00204    /* Move along.  There's nothing to see here... */
00205    float t;
00206    t = *cr * dr[bit] - *ci * di[bit];
00207    *ci = *cr * di[bit] + *ci * dr[bit];
00208    *cr = t;
00209    
00210    t = 2.0 - (*cr * *cr + *ci * *ci);
00211    *cr *= t;
00212    *ci *= t;
00213    return *cr;
00214 }  

void tdd_init ( void   ) 

Initializes the TDD system. Mostly stuff for inverse FFT

Definition at line 93 of file tdd.c.

References TDD_MARK, and TDD_SPACE.

Referenced by main().

00094 {
00095    /* Initialize stuff for inverse FFT */
00096    dr[0] = cos(TDD_SPACE * 2.0 * M_PI / 8000.0);
00097    di[0] = sin(TDD_SPACE * 2.0 * M_PI / 8000.0);
00098    dr[1] = cos(TDD_MARK * 2.0 * M_PI / 8000.0);
00099    di[1] = sin(TDD_MARK * 2.0 * M_PI / 8000.0);
00100 }

struct tdd_state* tdd_new ( void   ) 

This function returns a malloc'd instance of the tdd_state data structure. Returns a pointer to a malloc'd tdd_state structure, or NULL on error.

Definition at line 102 of file tdd.c.

References ast_log(), calloc, and LOG_WARNING.

Referenced by dahdi_setoption().

00103 {
00104    struct tdd_state *tdd;
00105    tdd = calloc(1, sizeof(*tdd));
00106    if (tdd) {
00107       tdd->fskd.spb = 176;        /* 45.5 baud */
00108       tdd->fskd.hdlc = 0;         /* Async */
00109       tdd->fskd.nbit = 5;         /* 5 bits */
00110       tdd->fskd.nstop = 1.5;      /* 1.5 stop bits */
00111       tdd->fskd.paridad = 0;      /* No parity */
00112       tdd->fskd.bw=0;             /* Filter 75 Hz */
00113       tdd->fskd.f_mark_idx = 0;   /* 1400 Hz */
00114       tdd->fskd.f_space_idx = 1;  /* 1800 Hz */
00115       tdd->fskd.pcola = 0;        /* No clue */
00116       tdd->fskd.cont = 0;         /* Digital PLL reset */
00117       tdd->fskd.x0 = 0.0;
00118       tdd->fskd.state = 0;
00119       tdd->pos = 0;
00120       tdd->mode = 0;
00121       tdd->charnum = 0;
00122    } else
00123       ast_log(LOG_WARNING, "Out of memory\n");
00124    return tdd;
00125 }


Variable Documentation

float di[4] [static]

Definition at line 59 of file tdd.c.

Referenced by dialed_interface_destroy(), dialed_interface_duplicate(), and try_calling().

float dr[4] [static]

Definition at line 59 of file tdd.c.

Referenced by abort_request(), append_transaction(), build_transactions(), cancel_request(), check_request(), discover_transactions(), dundi_do_lookup(), dundi_lookup_internal(), dundi_lookup_local(), dundi_lookup_thread(), dundi_precache_internal(), dundi_prop_precache(), dundi_query_eid_internal(), dundifunc_read(), optimize_transactions(), precache_trans(), precache_transactions(), query_transactions(), register_request(), and unregister_request().

float tddsb = 176.0 [static]

Definition at line 60 of file tdd.c.


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