80 lines
2.6 KiB
C
80 lines
2.6 KiB
C
/* $NetBSD: dtmf.c,v 1.3 2013/08/11 06:31:00 dholland Exp $ */
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/*
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* Copyright (c) 2010 Jared D. McNeill <jmcneill@invisible.ca>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/endian.h>
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#include <fcntl.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "dtmf.h"
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#define PI2 (3.14159265358979323846f * 2)
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static void
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dtmf_create(int16_t *buf, unsigned int sample_rate,
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unsigned short sample_length, unsigned short channels,
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unsigned int chanmask, float freq1, float freq2)
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{
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int c;
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unsigned i;
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size_t sample_count = sample_rate * sample_length;
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for (i = 0; i < sample_count; i++) {
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for (c = 0; c < channels; c++) {
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if ((chanmask & (1 << c)) == 0)
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continue;
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buf[c] = htole16(
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(sin(i * PI2 * (freq1 / sample_rate)) +
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sin(i * PI2 * (freq2 / sample_rate))) * 16383
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);
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}
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buf += channels;
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}
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}
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void
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dtmf_new(int16_t **buf, size_t *buflen, unsigned int sample_rate,
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unsigned short sample_length, unsigned short channels,
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unsigned int chanmask, float rate1, float rate2)
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{
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*buflen = sample_rate * sizeof(int16_t) * sample_length * channels;
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*buf = calloc(1, *buflen);
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if (*buf == NULL) {
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perror("calloc");
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return;
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}
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dtmf_create(*buf, sample_rate, sample_length, channels, chanmask,
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rate1, rate2);
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}
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