dtmfgenerator.cpp

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/**
 * Copyright (C) 2004-2005 Savoir-Faire Linux inc.
 * Author: Yan Morin <[e-mail]>
 * Author: Laurielle Lea <[e-mail]> 
 *
 * Portions (c) 2003 iptel.org
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Library 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 Library General Public
 * License for more details.
 * 
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 *
 */

#include <math.h>

#include "dtmfgenerator.h"
#include "../global.h"


/*
 * Tone frequencies
 */
const DTMFGenerator::DTMFTone DTMFGenerator::tones[NUM_TONES] = {
	{'0', 941, 1336},
	{'1', 697, 1209},
	{'2', 697, 1336},
	{'3', 697, 1477},
	{'4', 770, 1209},
	{'5', 770, 1336},
	{'6', 770, 1477},
	{'7', 852, 1209},
	{'8', 852, 1336},
	{'9', 852, 1477},
	{'A', 697, 1633},
	{'B', 770, 1633},
	{'C', 852, 1633},
	{'D', 941, 1633},
	{'*', 941, 1209},
	{'#', 941, 1477}
};


DTMFException::DTMFException(const char* _reason) throw()
{
	reason = _reason;
}


DTMFException::~DTMFException() throw()
{
}


const char* DTMFException::what() const throw()
{
	return reason;
}



/*
 * Initialize the generator
 */
DTMFGenerator::DTMFGenerator(unsigned int sampleRate) : tone("", sampleRate) 
{
  _sampleRate = sampleRate;
  state.offset = 0;
  state.sample = 0;

  for(int i = 0; i < NUM_TONES; i++) {
    samples[i] = generateSample(i);
  }
}
	

DTMFGenerator::~DTMFGenerator() {
  for(int i = 0; i < NUM_TONES; i++) {
    delete[] samples[i]; samples[i] = NULL;
  }
}


/*
 * Get n samples of the signal of code code
 */
void DTMFGenerator::getSamples(SFLDataFormat* buffer, size_t n, unsigned char code) throw(DTMFException) {
	size_t i;
	if (!buffer) {
	  throw DTMFException("Invalid parameter value");
	}

	switch(code) {
	case '0': state.sample = samples[0];  break;
	case '1': state.sample = samples[1];  break;
	case '2': state.sample = samples[2];  break;
	case '3': state.sample = samples[3];  break;
	case '4': state.sample = samples[4];  break;
	case '5': state.sample = samples[5];  break;
	case '6': state.sample = samples[6];  break;
	case '7': state.sample = samples[7];  break;
	case '8': state.sample = samples[8];  break;
	case '9': state.sample = samples[9];  break;
	case 'A':
	case 'a': state.sample = samples[10]; break;
	case 'B':
	case 'b': state.sample = samples[11]; break;
	case 'C':
	case 'c': state.sample = samples[12]; break;
	case 'D':
	case 'd': state.sample = samples[13]; break;
	case '*': state.sample = samples[14]; break;
	case '#': state.sample = samples[15]; break;
	default:
			throw DTMFException("Invalid code");
		return;
		break;
	}

	for(i = 0; i < n; i++) {
		buffer[i] = state.sample[i % _sampleRate];
	}

	state.offset = i % _sampleRate;
}


/*
 * Get next n samples (continues where previous call to
 * genSample or genNextSamples stopped
 */
void DTMFGenerator::getNextSamples(SFLDataFormat* buffer, size_t n) throw(DTMFException)
{
	size_t i;

	if (!buffer) {
	  throw DTMFException("Invalid parameter");
	}

	if (state.sample == 0) {
	  throw DTMFException("DTMF generator not initialized");
	}

	for(i = 0; i < n; i++) {
	  buffer[i] = state.sample[(state.offset + i) % _sampleRate];
	}
	
	state.offset = (state.offset + i) % _sampleRate;
}


/*
 * Generate a tone sample
 */
SFLDataFormat* DTMFGenerator::generateSample(unsigned char code) throw (DTMFException) {
	SFLDataFormat* ptr;

	try {
		ptr = new SFLDataFormat[_sampleRate]; 
		if (!ptr) {
			  throw new DTMFException("No memory left");
			return 0;
		}
		  
		tone.genSin(ptr, tones[code].higher, tones[code].lower,  _sampleRate);
		
		return ptr;
	} catch(...) {
			throw new DTMFException("No memory left");
			return 0;
	}

}