//
// This file is part of Dire Wolf, an amateur radio packet TNC.
//
// Copyright (C) 2013, 2015 John Langner, WB2OSZ
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
/*------------------------------------------------------------------
*
* Module: morse.c
*
* Purpose: Generate audio for morse code.
*
* Description:
*
* Reference:
*
*---------------------------------------------------------------*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <math.h>
#include "direwolf.h"
#include "textcolor.h"
#include "audio.h"
#include "ptt.h"
#include "gen_tone.h" /* for gen_tone_put_sample */
#include "morse.h"
/*
* Might get ambitious and make this adjustable some day.
* Good enough for now.
*/
#define MORSE_TONE 800
#define TIME_UNITS_TO_MS(tu,wpm) (((tu)*1200.0)/(wpm))
static const struct morse_s {
char ch;
char enc[8]; /* $ has 7 elements */
} morse[] = {
{ 'A', ".-" },
{ 'B', "-..." },
{ 'C', "-.-." },
{ 'D', "-.." },
{ 'E', "." },
{ 'F', "..-." },
{ 'G', "--." },
{ 'H', "...." },
{ 'I', "." },
{ 'J', ".---" },
{ 'K', "-.-" },
{ 'L', ".-.." },
{ 'M', "--" },
{ 'N', "-." },
{ 'O', "---" },
{ 'P', ".--." },
{ 'Q', "--.-" },
{ 'R', ".-." },
{ 'S', "..." },
{ 'T', "-" },
{ 'U', "..-" },
{ 'V', "...-" },
{ 'W', ".--" },
{ 'X', "-..-" },
{ 'Y', "-.--" },
{ 'Z', "--.." },
{ '1', ".----" },
{ '2', "..---" },
{ '3', "...--" },
{ '4', "....-" },
{ '5', "....." },
{ '6', "-...." },
{ '7', "--..." },
{ '8', "---.." },
{ '9', "----." },
{ '0', "-----" },
{ '-', "-...-" },
{ '.', ".-.-.-" },
{ ',', "--..--" },
{ '?', "..--.." },
{ '/', "-..-." },
{ '=', "-...-" }, /* from ARRL */
{ '-', "-....-" },
{ ')', "-.--.-" }, /* does not distinguish open/close */
{ ':', "---..." },
{ ';', "-.-.-." },
{ '"', ".-..-." },
{ '\'', ".----." },
{ '$', "...-..-" },
{ '!', "-.-.--" }, /* more from wikipedia */
{ '(', "-.--." },
{ '&', ".-..." },
{ '+', ".-.-." },
{ '_', "..--.-" },
{ '@', ".--.-." },
};
#define NUM_MORSE (sizeof(morse) / sizeof(struct morse_s))
static void morse_tone (int chan, int tu, int wpm);
static void morse_quiet (int chan, int tu, int wpm);
static void morse_quiet_ms (int chan, int ms);
static int morse_lookup (int ch);
static int morse_units_ch (int ch);
static int morse_units_str (char *str);
/*
* Properties of the digitized sound stream.
*/
static struct audio_s *save_audio_config_p;
/* Constants after initialization. */
#define TICKS_PER_CYCLE ( 256.0 * 256.0 * 256.0 * 256.0 )
static short sine_table[256];
/*------------------------------------------------------------------
*
* Name: morse_init
*
* Purpose: Initialize for tone generation.
*
* Inputs: audio_config_p - Pointer to audio configuration structure.
*
* The fields we care about are:
*
* samples_per_sec
*
* amp - Signal amplitude on scale of 0 .. 100.
*
* 100 will produce maximum amplitude of +-32k samples.
*
* Returns: 0 for success.
* -1 for failure.
*
* Description: Precompute a sine wave table.
*
*----------------------------------------------------------------*/
int morse_init (struct audio_s *audio_config_p, int amp)
{
int j;
/*
* Save away modem parameters for later use.
*/
save_audio_config_p = audio_config_p;
for (j=0; j<256; j++) {
double a;
int s;
a = ((double)(j) / 256.0) * (2 * M_PI);
s = (int) (sin(a) * 32767.0 * amp / 100.0);
/* 16 bit sound sample is in range of -32768 .. +32767. */
assert (s >= -32768 && s <= 32767);
sine_table[j] = s;
}
return (0);
} /* end morse_init */
/*-------------------------------------------------------------------
*
* Name: morse_send
*
* Purpose: Given a string, generate appropriate lengths of
* tone and silence.
*
* Inputs: chan - Radio channel number.
* str - Character string to send.
* wpm - Speed in words per minute.
* txdelay - Delay (ms) from PTT to first character.
* txtail - Delay (ms) from last character to PTT off.
*
*
* Returns: Total number of milliseconds to activate PTT.
* This includes delays before the first character
* and after the last to avoid chopping off part of it.
*
* Description: xmit_thread calls this instead of the usual hdlc_send
* when we have a special packet that means send morse
* code.
*
*--------------------------------------------------------------------*/
int morse_send (int chan, char *str, int wpm, int txdelay, int txtail)
{
int time_units;
char *p;
time_units = 0;
morse_quiet_ms (chan, txdelay);
for (p = str; *p != '\0'; p++) {
int i;
i = morse_lookup (*p);
if (i >= 0) {
const char *e;
for (e = morse[i].enc; *e != '\0'; e++) {
if (*e == '.') {
morse_tone (chan,1,wpm);
time_units++;
}
else {
morse_tone (chan,3,wpm);
time_units += 3;
}
if (e[1] != '\0') {
morse_quiet (chan,1,wpm);
time_units++;
}
}
}
else {
morse_quiet (chan,1,wpm);
time_units++;
}
if (p[1] != '\0') {
morse_quiet (chan,3,wpm);
time_units += 3;
}
}
morse_quiet_ms (chan, txtail);
if (time_units != morse_units_str(str)) {
dw_printf ("morse: Internal error. Inconsistent length, %d vs. %d calculated.\n",
time_units, morse_units_str(str));
}
return (txdelay +
(int) (TIME_UNITS_TO_MS(time_units, wpm) + 0.5) +
txtail);
} /* end morse_send */
/*-------------------------------------------------------------------
*
* Name: morse_tone
*
* Purpose: Generate tone for specified number of time units.
*
* Inputs: chan - Radio channel.
* tu - Number of time units. Should be 1 or 3.
* wpm - Speed in WPM.
*
*--------------------------------------------------------------------*/
static void morse_tone (int chan, int tu, int wpm) {
#if MTEST1
int n;
for (n=0; n<tu; n++) {
dw_printf ("#");
}
#else
int a = ACHAN2ADEV(chan); /* device for channel. */
int sam;
int nsamples;
int j;
unsigned int tone_phase; // Phase accumulator for tone generation.
// Upper bits are used as index into sine table.
int f1_change_per_sample; // How much to advance phase for each audio sample.
assert (save_audio_config_p->achan[chan].valid);
tone_phase = 0;
f1_change_per_sample = (int) (((double)MORSE_TONE * TICKS_PER_CYCLE / (double)save_audio_config_p->adev[a].samples_per_sec ) + 0.5);
nsamples = (int) ((TIME_UNITS_TO_MS(tu,wpm) * (float)save_audio_config_p->adev[a].samples_per_sec / 1000.) + 0.5);
for (j=0; j<nsamples; j++) {
tone_phase += f1_change_per_sample;
sam = sine_table[(tone_phase >> 24) & 0xff];
gen_tone_put_sample (chan, a, sam);
};
#endif
} /* end morse_tone */
/*-------------------------------------------------------------------
*
* Name: morse_quiet
*
* Purpose: Generate silence for specified number of time units.
*
* Inputs: chan - Radio channel.
* tu - Number of time units.
* wpm - Speed in WPM.
*
*--------------------------------------------------------------------*/
static void morse_quiet (int chan, int tu, int wpm) {
#if MTEST1
int n;
for (n=0; n<tu; n++) {
dw_printf (".");
}
#else
int a = ACHAN2ADEV(chan); /* device for channel. */
int sam = 0;
int nsamples;
int j;
assert (save_audio_config_p->achan[chan].valid);
nsamples = (int) ((TIME_UNITS_TO_MS(tu,wpm) * (float)save_audio_config_p->adev[a].samples_per_sec / 1000.) + 0.5);
for (j=0; j<nsamples; j++) {
gen_tone_put_sample (chan, a, sam);
};
#endif
} /* end morse_quiet */
/*-------------------------------------------------------------------
*
* Name: morse_quiet
*
* Purpose: Generate silence for specified number of milliseconds.
* This is used for the txdelay and txtail times.
*
* Inputs: chan - Radio channel.
* tu - Number of time units.
*
*--------------------------------------------------------------------*/
static void morse_quiet_ms (int chan, int ms) {
#if MTEST1
#else
int a = ACHAN2ADEV(chan); /* device for channel. */
int sam = 0;
int nsamples;
int j;
assert (save_audio_config_p->achan[chan].valid);
nsamples = (int) ((ms * (float)save_audio_config_p->adev[a].samples_per_sec / 1000.) + 0.5);
for (j=0; j<nsamples; j++) {
gen_tone_put_sample (chan, a, sam);
};
#endif
} /* end morse_quiet_ms */
/*-------------------------------------------------------------------
*
* Name: morse_lookup
*
* Purpose: Given a character, find index in table above.
*
* Inputs: ch
*
* Returns: Index into table above or -1 if not found.
* Notice that space is not in the table.
* Any unusual character, that is not in the table,
* ends up being treated like space.
*
*--------------------------------------------------------------------*/
static int morse_lookup (int ch)
{
int i;
if (islower(ch)) {
ch = toupper(ch);
}
for (i=0; i<NUM_MORSE; i++) {
if (ch == morse[i].ch) {
return (i);
}
}
return (-1);
}
/*-------------------------------------------------------------------
*
* Name: morse_units_ch
*
* Purpose: Find number of time units for a character.
*
* Inputs: ch
*
* Returns: 1 for E (.)
* 3 for T (-)
* 3 for I.= (..)
* etc.
*
* The one unexpected result is 1 for space. Why not 7?
* When a space appears between two other characters,
* we already have 3 before and after so only 1 more is needed.
*
*--------------------------------------------------------------------*/
static int morse_units_ch (int ch)
{
int i;
int len;
int k;
int units;
i = morse_lookup (ch);
if (i < 0) {
return (1); /* space or any invalid character */
}
len = strlen(morse[i].enc);
units = len - 1;
for (k = 0; k < len; k++) {
switch (morse[i].enc[k]) {
case '.': units++; break;
case '-': units += 3; break;
default: dw_printf ("ERROR: morse_units_ch: should not be here.\n"); break;
}
}
return (units);
}
/*-------------------------------------------------------------------
*
* Name: morse_units_str
*
* Purpose: Find number of time units for a string of characters.
*
* Inputs: str
*
* Returns: 1 for E
* 5 for EE (1 + 3 + 1)
* 9 for E E (1 + 7 + 1)
* etc.
*
*--------------------------------------------------------------------*/
static int morse_units_str (char *str)
{
//int i;
int len;
int k;
int units;
len = strlen(str);
units = (len - 1) * 3;
for (k = 0; k < len; k++) {
units += morse_units_ch(str[k]);
}
return (units);
}
#if MTEST1
int main (int argc, char *argv[]) {
dw_printf ("CQ DX\n");
morse_send (0, "CQ DX", 10, 10, 10);
dw_printf ("\n\n");
dw_printf ("wb2osz/9\n");
morse_send (0, "wb2osz/9", 10, 10, 10);
dw_printf ("\n\n");
}
#endif
/* end morse.c */