1 // morse.cxx -- Morse code generation class
3 // Written by Curtis Olson, started March 2001.
5 // Copyright (C) 2001 Curtis L. Olson - curt@flightgear.org
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 #include <simgear/constants.h>
29 static const char alphabet[26][4] = {
30 { DI, DAH, end, end }, /* A */
31 { DA, DI, DI, DIT }, /* B */
32 { DA, DI, DA, DIT }, /* C */
33 { DA, DI, DIT, end }, /* D */
34 { DIT, end, end, end }, /* E */
35 { DI, DI, DA, DIT }, /* F */
36 { DA, DA, DIT, end }, /* G */
37 { DI, DI, DI, DIT }, /* H */
38 { DI, DIT, end, end }, /* I */
39 { DI, DA, DA, DAH }, /* J */
40 { DA, DI, DAH, end }, /* K */
41 { DI, DA, DI, DIT }, /* L */
42 { DA, DAH, end, end }, /* M */
43 { DA, DIT, end, end }, /* N */
44 { DA, DA, DAH, end }, /* O */
45 { DI, DA, DA, DIT }, /* P */
46 { DA, DA, DI, DAH }, /* Q */
47 { DI, DA, DIT, end }, /* R */
48 { DI, DI, DIT, end }, /* S */
49 { DAH, end, end, end }, /* T */
50 { DI, DI, DAH, end }, /* U */
51 { DI, DI, DI, DAH }, /* V */
52 { DI, DA, DAH, end }, /* W */
53 { DA, DI, DI, DAH }, /* X */
54 { DA, DI, DA, DAH }, /* Y */
55 { DA, DA, DI, DIT } /* Z */
68 // Make a tone of specified freq and total_len with trans_len ramp in
69 // and out and only the first len bytes with sound, the rest with
71 void make_tone( unsigned char *buf, int freq,
72 int len, int total_len, int trans_len )
76 for ( i = 0; i < trans_len; ++i ) {
77 float level = ( sin( (double) i * 2.0 * SGD_PI / (8000.0 / freq) ) )
78 * ((double)i / trans_len) / 2.0 + 0.5;
80 /* Convert to unsigned byte */
81 buf[ i ] = (unsigned char) ( level * 255.0 ) ;
84 for ( i = trans_len; i < len - trans_len; ++i ) {
85 float level = ( sin( (double) i * 2.0 * SGD_PI / (8000.0 / freq) ) )
88 /* Convert to unsigned byte */
89 buf[ i ] = (unsigned char) ( level * 255.0 ) ;
92 for ( i = len - trans_len; i < len; ++i ) {
93 float level = ( sin( (double) i * 2.0 * SGD_PI / (8000.0 / freq) ) )
94 * ((double)j / trans_len) / 2.0 + 0.5;
97 /* Convert to unsigned byte */
98 buf[ i ] = (unsigned char) ( level * 255.0 ) ;
100 for ( i = len; i < total_len; ++i ) {
101 buf[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
106 // allocate and initialize sound samples
107 bool FGMorse::init() {
109 make_tone( lo_dit, LO_FREQUENCY, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
113 make_tone( hi_dit, HI_FREQUENCY, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
117 make_tone( lo_dah, LO_FREQUENCY, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
121 make_tone( hi_dah, HI_FREQUENCY, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
126 for ( i = 0; i < SPACE_SIZE; ++i ) {
127 space[ i ] = (unsigned char) ( 0.5 * 255 ) ;
134 // allocate and initialize sound samples
135 bool FGMorse::cust_init(const int freq ) {
139 make_tone( cust_dit, freq, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
143 make_tone( cust_dah, freq, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
147 for ( i = 0; i < SPACE_SIZE; ++i ) {
148 space[ i ] = (unsigned char) ( 0.5 * 255 ) ;
155 // make a FGSimpleSound morse code transmission for the specified string
156 FGSimpleSound *FGMorse::make_ident( const string& id, const int freq ) {
157 char *idptr = (char *)id.c_str();
162 // 0. Select the frequency. If custom frequency, generate the
163 // sound fragments we need on the fly.
164 unsigned char *dit_ptr, *dah_ptr;
166 if ( freq == LO_FREQUENCY ) {
169 } else if ( freq == HI_FREQUENCY ) {
178 // 1. Determine byte length of message
179 for ( i = 0; i < (int)id.length(); ++i ) {
180 if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
181 char c = idptr[i] - 'A';
182 for ( j = 0; j < 4 || alphabet[c][j] == end; ++j ) {
183 if ( alphabet[c][j] == DIT ) {
185 } else if ( alphabet[c][j] == DAH ) {
189 length += SPACE_SIZE;
191 // skip unknown character
194 // add 2x more space to the end of the string
195 length += 2 * SPACE_SIZE;
197 // 2. Allocate space for the message
198 unsigned char *buffer = new unsigned char[length];
200 // 3. Assemble the message;
201 unsigned char *buf_ptr = buffer;
203 for ( i = 0; i < (int)id.length(); ++i ) {
204 if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
205 char c = idptr[i] - 'A';
206 for ( j = 0; j < 4 || alphabet[c][j] == end; ++j ) {
207 if ( alphabet[c][j] == DIT ) {
208 memcpy( buf_ptr, dit_ptr, DIT_SIZE );
210 } else if ( alphabet[c][j] == DAH ) {
211 memcpy( buf_ptr, dah_ptr, DAH_SIZE );
215 memcpy( buf_ptr, space, SPACE_SIZE );
216 buf_ptr += SPACE_SIZE;
218 // skip unknown character
221 memcpy( buf_ptr, space, SPACE_SIZE );
222 buf_ptr += SPACE_SIZE;
223 memcpy( buf_ptr, space, SPACE_SIZE );
224 buf_ptr += SPACE_SIZE;
226 // 4. create the simple sound and return
227 FGSimpleSound *sample = new FGSimpleSound( buffer, length );