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.
27 static const char alphabet[26][4] = {
28 { DI, DAH, end, end }, /* A */
29 { DA, DI, DI, DIT }, /* B */
30 { DA, DI, DA, DIT }, /* C */
31 { DA, DI, DIT, end }, /* D */
32 { DIT, end, end, end }, /* E */
33 { DI, DI, DA, DIT }, /* F */
34 { DA, DA, DIT, end }, /* G */
35 { DI, DI, DI, DIT }, /* H */
36 { DI, DIT, end, end }, /* I */
37 { DI, DA, DA, DAH }, /* J */
38 { DA, DI, DAH, end }, /* K */
39 { DI, DA, DI, DIT }, /* L */
40 { DA, DAH, end, end }, /* M */
41 { DA, DIT, end, end }, /* N */
42 { DA, DA, DAH, end }, /* O */
43 { DI, DA, DA, DIT }, /* P */
44 { DA, DA, DI, DAH }, /* Q */
45 { DI, DA, DIT, end }, /* R */
46 { DI, DI, DIT, end }, /* S */
47 { DAH, end, end, end }, /* T */
48 { DI, DI, DAH, end }, /* U */
49 { DI, DI, DI, DAH }, /* V */
50 { DI, DA, DAH, end }, /* W */
51 { DA, DI, DI, DAH }, /* X */
52 { DA, DI, DA, DAH }, /* Y */
53 { DA, DA, DI, DIT } /* Z */
66 // allocate and initialize sound samples
67 bool FGMorse::init() {
71 for ( i = 0; i < TRANSITION_BYTES; ++i ) {
72 float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY)) )
73 * ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
75 /* Convert to unsigned byte */
76 dit[ i ] = (unsigned char) ( level * 255.0 ) ;
79 for ( i = TRANSITION_BYTES;
80 i < DIT_SIZE - TRANSITION_BYTES - COUNT_SIZE; ++i ) {
81 float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
84 /* Convert to unsigned byte */
85 dit[ i ] = (unsigned char) ( level * 255.0 ) ;
88 for ( i = DIT_SIZE - TRANSITION_BYTES - COUNT_SIZE;
89 i < DIT_SIZE - COUNT_SIZE;
91 float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
92 * ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
95 /* Convert to unsigned byte */
96 dit[ i ] = (unsigned char) ( level * 255.0 ) ;
98 for ( i = DIT_SIZE - COUNT_SIZE; i < DIT_SIZE; ++i ) {
99 dit[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
103 for ( i = 0; i < TRANSITION_BYTES; ++i ) {
104 float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
105 * ((double)i / TRANSITION_BYTES) / 2.0 + 0.5;
107 /* Convert to unsigned byte */
108 dah[ i ] = (unsigned char) ( level * 255.0 ) ;
111 for ( i = TRANSITION_BYTES;
112 i < DAH_SIZE - TRANSITION_BYTES - COUNT_SIZE;
114 float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
117 /* Convert to unsigned byte */
118 dah[ i ] = (unsigned char) ( level * 255.0 ) ;
120 j = TRANSITION_BYTES;
121 for ( int i = DAH_SIZE - TRANSITION_BYTES - COUNT_SIZE;
122 i < DAH_SIZE - COUNT_SIZE;
124 float level = ( sin( (double) i * 2.0 * M_PI / (8000.0 / FREQUENCY) ) )
125 * ((double)j / TRANSITION_BYTES) / 2.0 + 0.5;
128 /* Convert to unsigned byte */
129 dah[ i ] = (unsigned char) ( level * 255.0 ) ;
131 for ( int i = DAH_SIZE - COUNT_SIZE; i < DAH_SIZE; ++i ) {
132 dah[ i ] = (unsigned char) ( 0.5 * 255.0 ) ;
136 for ( int i = 0; i < SPACE_SIZE; ++i ) {
137 space[ i ] = (unsigned char) ( 0.5 * 255 ) ;
144 // make a FGSimpleSound morse code transmission for the specified string
145 FGSimpleSound *FGMorse::make_ident( const string& id ) {
146 char *idptr = (char *)id.c_str();
151 // 1. Determine byte length of message
152 for ( i = 0; i < (int)id.length(); ++i ) {
153 if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
154 char c = idptr[i] - 'A';
155 for ( j = 0; j < 4 || alphabet[c][j] == end; ++j ) {
156 if ( alphabet[c][j] == DIT ) {
158 } else if ( alphabet[c][j] == DAH ) {
162 length += SPACE_SIZE;
164 // skip unknown character
168 // 2. Allocate space for the message
169 unsigned char *buffer = new unsigned char[length];
171 // 3. Assemble the message;
172 unsigned char *bufptr = buffer;
174 for ( i = 0; i < (int)id.length(); ++i ) {
175 if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
176 char c = idptr[i] - 'A';
177 for ( j = 0; j < 4 || alphabet[c][j] == end; ++j ) {
178 if ( alphabet[c][j] == DIT ) {
179 memcpy( bufptr, dit, DIT_SIZE );
181 } else if ( alphabet[c][j] == DAH ) {
182 memcpy( bufptr, dah, DAH_SIZE );
186 memcpy( bufptr, space, SPACE_SIZE );
187 bufptr += SPACE_SIZE;
189 // skip unknown character
193 // 4. create the simple sound and return
194 FGSimpleSound *sample = new FGSimpleSound( buffer, length );