/* $NetBSD: dtmf.c,v 1.3.28.1 2019/09/29 07:34:09 martin Exp $ */ /* * Copyright (c) 2010 Jared D. McNeill * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include #include #include #include #include #include #include #include #include #include "dtmf.h" #define PI2 (3.14159265358979323846f * 2) static void dtmf_create(int16_t *buf, unsigned int sample_rate, unsigned short sample_length, unsigned short channels, unsigned int chanmask, float freq1, float freq2) { int c; unsigned i; size_t sample_count = sample_rate * sample_length; for (i = 0; i < sample_count; i++) { for (c = 0; c < channels; c++) { if ((chanmask & (1 << c)) == 0) continue; buf[c] = htole16( (sin(i * PI2 * (freq1 / sample_rate)) + sin(i * PI2 * (freq2 / sample_rate))) * 16383 ); } buf += channels; } } void dtmf_new(int16_t **buf, size_t *buflen, unsigned int sample_rate, unsigned short sample_length, unsigned short channels, unsigned int chanmask, float rate1, float rate2) { *buflen = sample_rate * sizeof(int16_t) * sample_length * channels; *buf = calloc(1, *buflen); if (*buf == NULL) { warn("calloc"); return; } dtmf_create(*buf, sample_rate, sample_length, channels, chanmask, rate1, rate2); }