morse.cxx

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// morse.cxx -- Morse code generation class
//
// Written by Curtis Olson, started March 2001.
//
// Copyright (C) 2001  Curtis L. Olson - http://www.flightgear.org/~curt
//
// 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, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//
 
 
#include <simgear/constants.h>
 
#include "morse.hxx"
 
#include <simgear/sound/sample.hxx>
 
#include <cstdlib>
#include <cstring>
#include <utility>
 
static const char DI = '1';
static const char DIT = '1';
static const char DA = '2';
static const char DAH = '2';
static const char END = '0';
 
static const char alphabet[26][4] = {
    { DI, DAH, END, END },   /* A */ 
    { DA, DI, DI, DIT },       /* B */ 
    { DA, DI, DA, DIT },       /* C */ 
    { DA, DI, DIT, END },     /* D */ 
    { DIT, END, END, END }, /* E */ 
    { DI, DI, DA, DIT },       /* F */ 
    { DA, DA, DIT, END },     /* G */ 
    { DI, DI, DI, DIT },       /* H */ 
    { DI, DIT, END, END },   /* I */ 
    { DI, DA, DA, DAH },       /* J */ 
    { DA, DI, DAH, END },     /* K */ 
    { DI, DA, DI, DIT },       /* L */ 
    { DA, DAH, END, END },   /* M */ 
    { DA, DIT, END, END },   /* N */ 
    { DA, DA, DAH, END },     /* O */ 
    { DI, DA, DA, DIT },       /* P */ 
    { DA, DA, DI, DAH },       /* Q */ 
    { DI, DA, DIT, END },     /* R */ 
    { DI, DI, DIT, END },     /* S */ 
    { DAH, END, END, END }, /* T */ 
    { DI, DI, DAH, END },     /* U */ 
    { DI, DI, DI, DAH },       /* V */ 
    { DI, DA, DAH, END },     /* W */ 
    { DA, DI, DI, DAH },       /* X */ 
    { DA, DI, DA, DAH },       /* Y */ 
    { DA, DA, DI, DIT }                /* Z */ 
};
 
static const char numerals[10][5] = {
    { DA, DA, DA, DA, DAH },    // 0
    { DI, DA, DA, DA, DAH },    // 1
    { DI, DI, DA, DA, DAH },    // 2
    { DI, DI, DI, DA, DAH },    // 3
    { DI, DI, DI, DI, DAH },    // 4
    { DI, DI, DI, DI, DIT },    // 5
    { DA, DI, DI, DI, DIT },    // 6
    { DA, DA, DI, DI, DIT },    // 7
    { DA, DA, DA, DI, DIT },    // 8
    { DA, DA, DA, DA, DIT }     // 9
};
 
 
// constructor
FGMorse::FGMorse() {
}
 
// destructor
FGMorse::~FGMorse() {
}
 
 
// allocate and initialize sound samples
bool FGMorse::init() {
    // Make Low DIT
    make_tone( lo_dit, LO_FREQUENCY, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
               TRANSITION_BYTES );
 
    // Make High DIT
    make_tone( hi_dit, HI_FREQUENCY, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
               TRANSITION_BYTES );
 
    // Make Low DAH
    make_tone( lo_dah, LO_FREQUENCY, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
               TRANSITION_BYTES );
 
    // Make High DAH
    make_tone( hi_dah, HI_FREQUENCY, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
               TRANSITION_BYTES );
 
    // Make SPACE
    int i;
    for ( i = 0; i < SPACE_SIZE; ++i ) {
        space[ i ] = (unsigned char) ( 0.5 * 255 ) ;
    }
 
    return true;
}
 
 
// allocate and initialize sound samples
bool FGMorse::cust_init(const int freq ) {
    int i;
 
    // Make DIT
    make_tone( cust_dit, freq, DIT_SIZE - COUNT_SIZE, DIT_SIZE,
               TRANSITION_BYTES );
 
    // Make DAH
    make_tone( cust_dah, freq, DAH_SIZE - COUNT_SIZE, DAH_SIZE,
               TRANSITION_BYTES );
 
    // Make SPACE
    for ( i = 0; i < SPACE_SIZE; ++i ) {
        space[ i ] = (unsigned char) ( 0.5 * 255 ) ;
    }
 
    return true;
}
 
 
// make a SGSoundSample morse code transmission for the specified string
SGSoundSample *FGMorse::make_ident( const std::string& id, const int freq ) {
 
    char *idptr = (char *)id.c_str();
 
    int length = 0;
    int i, j;
 
    // 0. Select the frequency.  If custom frequency, generate the
    // sound fragments we need on the fly.
    unsigned char *dit_ptr, *dah_ptr;
 
    if ( freq == LO_FREQUENCY ) {
        dit_ptr = lo_dit;
        dah_ptr = lo_dah;
    } else if ( freq == HI_FREQUENCY ) {
        dit_ptr = hi_dit;
        dah_ptr = hi_dah;
    } else {
        cust_init( freq );
        dit_ptr = cust_dit;
        dah_ptr = cust_dah;
    }
 
    // 1. Determine byte length of message
    for ( i = 0; i < (int)id.length(); ++i ) {
        if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
            int c = (int)(idptr[i] - 'A');
            for ( j = 0; j < 4 && alphabet[c][j] != END; ++j ) {
                if ( alphabet[c][j] == DIT ) {
                    length += DIT_SIZE;
                } else if ( alphabet[c][j] == DAH ) {
                    length += DAH_SIZE;
                }
            }
            length += SPACE_SIZE;
        } else if ( idptr[i] >= '0' && idptr[i] <= '9' ) {
            int c = (int)(idptr[i] - '0');
            for ( j = 0; j < 5; ++j) {
                if ( numerals[c][j] == DIT ) {
                    length += DIT_SIZE;
                } else if ( numerals[c][j] == DAH ) {
                    length += DAH_SIZE;
                }
            }
            length += SPACE_SIZE;
        } else {
            // skip unknown character
        }
    }
    // add 2x more space to the end of the string
    length += 2 * SPACE_SIZE;
 
    // 2. Allocate space for the message
    auto buffer = std::unique_ptr<unsigned char, decltype(free)*>{
          reinterpret_cast<unsigned char*>( malloc( length ) ),
          free
    };
 
    // 3. Assemble the message;
    unsigned char *buf_ptr = buffer.get();
 
    for ( i = 0; i < (int)id.length(); ++i ) {
        if ( idptr[i] >= 'A' && idptr[i] <= 'Z' ) {
            int c = (int)(idptr[i] - 'A');
            for ( j = 0; j < 4 && alphabet[c][j] != END; ++j ) {
                if ( alphabet[c][j] == DIT ) {
                    memcpy( buf_ptr, dit_ptr, DIT_SIZE );
                    buf_ptr += DIT_SIZE;
                } else if ( alphabet[c][j] == DAH ) {
                    memcpy( buf_ptr, dah_ptr, DAH_SIZE );
                    buf_ptr += DAH_SIZE;
                }
            }
            memcpy( buf_ptr, space, SPACE_SIZE );
            buf_ptr += SPACE_SIZE;
        } else if ( idptr[i] >= '0' && idptr[i] <= '9' ) {
            int c = (int)(idptr[i] - '0');
            for ( j = 0; j < 5; ++j ) {
                if ( numerals[c][j] == DIT ) {
                    memcpy( buf_ptr, dit_ptr, DIT_SIZE );
                    buf_ptr += DIT_SIZE;
                } else if ( numerals[c][j] == DAH ) {
                    memcpy( buf_ptr, dah_ptr, DAH_SIZE );
                    buf_ptr += DAH_SIZE;
                }
            }
            memcpy( buf_ptr, space, SPACE_SIZE );
            buf_ptr += SPACE_SIZE;
        } else {
            // skip unknown character
        }
    }
    memcpy( buf_ptr, space, SPACE_SIZE );
    buf_ptr += SPACE_SIZE;
    memcpy( buf_ptr, space, SPACE_SIZE );
    buf_ptr += SPACE_SIZE;
 
    // 4. create the simple sound and return
    SGSoundSample *sample = new SGSoundSample( std::move(buffer), length,
                                               BYTES_PER_SECOND );
 
    sample->set_reference_dist( 10.0 );
    sample->set_max_dist( 20.0 );
 
    return sample;
}
 
FGMorse * FGMorse::_instance = NULL;
 
FGMorse * FGMorse::instance()
{
    if( _instance == NULL ) {
        _instance = new FGMorse();
        _instance->init();
    }
    return _instance;
}