1 // morse.cxx -- Morse code generation class
3 // Written by Curtis Olson, started March 2001.
5 // Copyright (C) 2001 Curtis L. Olson - http://www.flightgear.org/~curt
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
26 #include <simgear/constants.h>
31 static const char alphabet[26][4] = {
32 { DI, DAH, end, end }, /* A */
33 { DA, DI, DI, DIT }, /* B */
34 { DA, DI, DA, DIT }, /* C */
35 { DA, DI, DIT, end }, /* D */
36 { DIT, end, end, end }, /* E */
37 { DI, DI, DA, DIT }, /* F */
38 { DA, DA, DIT, end }, /* G */
39 { DI, DI, DI, DIT }, /* H */
40 { DI, DIT, end, end }, /* I */
41 { DI, DA, DA, DAH }, /* J */
42 { DA, DI, DAH, end }, /* K */
43 { DI, DA, DI, DIT }, /* L */
44 { DA, DAH, end, end }, /* M */
45 { DA, DIT, end, end }, /* N */
46 { DA, DA, DAH, end }, /* O */
47 { DI, DA, DA, DIT }, /* P */
48 { DA, DA, DI, DAH }, /* Q */
49 { DI, DA, DIT, end }, /* R */
50 { DI, DI, DIT, end }, /* S */
51 { DAH, end, end, end }, /* T */
52 { DI, DI, DAH, end }, /* U */
53 { DI, DI, DI, DAH }, /* V */
54 { DI, DA, DAH, end }, /* W */
55 { DA, DI, DI, DAH }, /* X */
56 { DA, DI, DA, DAH }, /* Y */
57 { DA, DA, DI, DIT } /* Z */
60 static const char numerals[10][5] = {
61 { DA, DA, DA, DA, DAH }, // 0
62 { DI, DA, DA, DA, DAH }, // 1
63 { DI, DI, DA, DA, DAH }, // 2
64 { DI, DI, DI, DA, DAH }, // 3
65 { DI, DI, DI, DI, DAH }, // 4
66 { DI, DI, DI, DI, DIT }, // 5
67 { DA, DI, DI, DI, DIT }, // 6
68 { DA, DA, DI, DI, DIT }, // 7
69 { DA, DA, DA, DI, DIT }, // 8
70 { DA, DA, DA, DA, DIT } // 9
83 // Make a tone of specified freq and total_len with trans_len ramp in
84 // and out and only the first len bytes with sound, the rest with
86 void make_tone( unsigned char *buf, int freq,
87 int len, int total_len, int trans_len )
91 for ( i = 0; i < trans_len; ++i ) {
92 float level = ( sin( (double) i * SGD_2PI / (BYTES_PER_SECOND / freq) ) )
93 * ((double)i / trans_len) / 2.0 + 0.5;
95 /* Convert to unsigned byte */
96 buf[ i ] = (unsigned char) ( level * 255.0 ) ;
99 for ( i = trans_len; i < len - trans_len; ++i ) {
100 float level = ( sin( (double) i * SGD_2PI / (BYTES_PER_SECOND / freq) ) )
103 /* Convert to unsigned byte */
104 buf[ i ] = (unsigned char) ( level * 255.0 ) ;
107 for ( i = len - trans_len; i < len; ++i ) {
108 float level = ( sin( (double) i * SGD_2PI / (BYTES_PER_SECOND / freq) ) )
109 * ((double)j / trans_len) / 2.0 + 0.5;
112 /* Convert to unsigned byte */
113 buf[ i ] = (unsigned char) ( level * 255.0 ) ;
115 for ( i = len; i < total_len; ++i ) {
116 buf[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
121 // allocate and initialize sound samples
122 bool FGMorse::init() {
124 make_tone( lo_dit, LO_FREQUENCY, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
128 make_tone( hi_dit, HI_FREQUENCY, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
132 make_tone( lo_dah, LO_FREQUENCY, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
136 make_tone( hi_dah, HI_FREQUENCY, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
141 for ( i = 0; i < SPACE_SIZE; ++i ) {
142 space[ i ] = (unsigned char) ( 0.5 * 255 ) ;
149 // allocate and initialize sound samples
150 bool FGMorse::cust_init(const int freq ) {
154 make_tone( cust_dit, freq, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
158 make_tone( cust_dah, freq, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
162 for ( i = 0; i < SPACE_SIZE; ++i ) {
163 space[ i ] = (unsigned char) ( 0.5 * 255 ) ;
170 // make a SGSoundSample morse code transmission for the specified string
171 SGSoundSample *FGMorse::make_ident( const string& id, const int freq ) {
173 char *idptr = (char *)id.c_str();
178 // 0. Select the frequency. If custom frequency, generate the
179 // sound fragments we need on the fly.
180 unsigned char *dit_ptr, *dah_ptr;
182 if ( freq == LO_FREQUENCY ) {
185 } else if ( freq == HI_FREQUENCY ) {
194 // 1. Determine byte length of message
195 for ( i = 0; i < (int)id.length(); ++i ) {
196 if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
197 int c = (int)(idptr[i] - 'A');
198 for ( j = 0; j < 4 || alphabet[c][j] == end; ++j ) {
199 if ( alphabet[c][j] == DIT ) {
201 } else if ( alphabet[c][j] == DAH ) {
205 length += SPACE_SIZE;
206 } else if ( idptr[i] >= '0' && idptr[i] <= '9' ) {
207 int c = (int)(idptr[i] - '0');
208 for ( j = 0; j < 5; ++j) {
209 if ( numerals[c][j] == DIT ) {
211 } else if ( numerals[c][j] == DAH ) {
215 length += SPACE_SIZE;
217 // skip unknown character
220 // add 2x more space to the end of the string
221 length += 2 * SPACE_SIZE;
223 // 2. Allocate space for the message
224 std::auto_ptr<unsigned char>buffer( new unsigned char[length] );
226 // 3. Assemble the message;
227 unsigned char *buf_ptr = buffer.get();
229 for ( i = 0; i < (int)id.length(); ++i ) {
230 if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
231 int c = (int)(idptr[i] - 'A');
232 for ( j = 0; j < 4 || alphabet[c][j] == end; ++j ) {
233 if ( alphabet[c][j] == DIT ) {
234 memcpy( buf_ptr, dit_ptr, DIT_SIZE );
236 } else if ( alphabet[c][j] == DAH ) {
237 memcpy( buf_ptr, dah_ptr, DAH_SIZE );
241 memcpy( buf_ptr, space, SPACE_SIZE );
242 buf_ptr += SPACE_SIZE;
243 } else if ( idptr[i] >= '0' && idptr[i] <= '9' ) {
244 int c = (int)(idptr[i] - '0');
245 for ( j = 0; j < 5; ++j ) {
246 if ( numerals[c][j] == DIT ) {
247 memcpy( buf_ptr, dit_ptr, DIT_SIZE );
249 } else if ( numerals[c][j] == DAH ) {
250 memcpy( buf_ptr, dah_ptr, DAH_SIZE );
254 memcpy( buf_ptr, space, SPACE_SIZE );
255 buf_ptr += SPACE_SIZE;
257 // skip unknown character
260 memcpy( buf_ptr, space, SPACE_SIZE );
261 buf_ptr += SPACE_SIZE;
262 memcpy( buf_ptr, space, SPACE_SIZE );
263 buf_ptr += SPACE_SIZE;
265 // 4. create the simple sound and return
266 SGSoundSample *sample = new SGSoundSample( buffer, length,
269 sample->set_reference_dist( 10.0 );
270 sample->set_max_dist( 20.0 );