--- /dev/null
+/*
+ * Copyright (C) 2015 Caleb Crome
+ * Copyright (C) 2013-2015 Intel Corporation
+ *
+ * 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.
+ *
+ */
+
+/*
+ * This is a general purpose sine wave generator that will stay stable
+ * for a long time, and with a little renormalization, could stay stay
+ * stable indefinitely
+ */
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <math.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "gettext.h"
+#include "common.h"
+#include "signal.h"
+
+/*
+ * Initialize the sine wave generator.
+ * sin_generator: gets initialized by this call.
+ * frequency: the frequency for the sine wave. must be < 0.5*sample_rate
+ * sample_rate: the sample rate...
+ * returns 0 on success, -1 on error.
+ */
+int sin_generator_init(struct sin_generator *sg, float magnitude,
+ float frequency, float sample_rate)
+{
+ /* angular frequency: cycles/sec / (samp/sec) * rad/cycle = rad/samp */
+ float w = frequency / sample_rate * 2 * M_PI;
+ if (frequency >= sample_rate / 2)
+ return -1;
+ sg->phasor_real = cos(w);
+ sg->phasor_imag = sin(w);
+ sg->magnitude = magnitude;
+ sg->state_real = 0.0;
+ sg->state_imag = magnitude;
+ sg->frequency = frequency;
+ sg->sample_rate = sample_rate;
+ return 0;
+}
+
+/*
+ * Generates the next sample in the sine wave.
+ * should be much faster than calling a sin function
+ * if it's inlined and optimized.
+ *
+ * returns the next value. no possibility of error.
+ */
+float sin_generator_next_sample(struct sin_generator *sg)
+{
+ /* get shorthand to pointers */
+ const double pr = sg->phasor_real;
+ const double pi = sg->phasor_imag;
+ const double sr = sg->state_real;
+ const double si = sg->state_imag;
+ /* step the phasor -- complex multiply */
+ sg->state_real = sr * pr - si * pi;
+ sg->state_imag = sr * pi + pr * si;
+ /* return the input value so sine wave starts at exactly 0.0 */
+ return sr;
+}
+
+/* fills a vector with a sine wave */
+void sin_generator_vfill(struct sin_generator *sg, float *buf, int n)
+{
+ int i;
+ for (i = 0; i < n; i++)
+ *buf++ = sin_generator_next_sample(sg);
+}
+
+static int reorder(struct bat *bat, float *val, int frames)
+{
+ float *new_buf = NULL;
+ int i, c, bytes;
+
+ bytes = frames * bat->channels * sizeof(float);
+
+ new_buf = (float *) malloc(bytes);
+ if (new_buf == NULL) {
+ fprintf(bat->err, _("Not enough memory.\n"));
+ return -ENOMEM;
+ }
+
+ memcpy(new_buf, val, bytes);
+ for (i = 0; i < frames; i++)
+ for (c = 0; c < bat->channels; c++)
+ val[i * bat->channels + c] =
+ new_buf[c * frames + i];
+ free(new_buf);
+
+ return 0;
+}
+
+static int adjust_waveform(struct bat *bat, float *val, int frames)
+{
+ int i, nsamples, max;
+ float factor, offset = 0.0;
+
+ switch (bat->format) {
+ case SND_PCM_FORMAT_U8:
+ max = INT8_MAX;
+ offset = max; /* shift for unsigned format */
+ break;
+ case SND_PCM_FORMAT_S16_LE:
+ max = INT16_MAX;
+ break;
+ case SND_PCM_FORMAT_S24_3LE:
+ max = (1 << 23) - 1;
+ break;
+ case SND_PCM_FORMAT_S32_LE:
+ max = INT32_MAX;
+ break;
+ default:
+ fprintf(bat->err, _("Invalid PCM format: %s\n"),
+ snd_pcm_format_name(bat->format));
+ return -EINVAL;
+ }
+
+ factor = max * RANGE_FACTOR;
+ nsamples = bat->channels * frames;
+
+ for (i = 0; i < nsamples; i++)
+ val[i] = val[i] * factor + offset;
+
+ return 0;
+}
+
+int generate_sine_wave(struct bat *bat, int frames, void *buf)
+{
+ int err = 0;
+ int c, nsamples;
+ float *sinus_f = NULL;
+ static struct sin_generator sg[MAX_CHANNELS];
+
+ nsamples = bat->channels * frames;
+ sinus_f = (float *) malloc(nsamples * sizeof(float));
+ if (sinus_f == NULL) {
+ fprintf(bat->err, _("Not enough memory.\n"));
+ return -ENOMEM;
+ }
+
+ for (c = 0; c < bat->channels; c++) {
+ /* initialize static struct at the first time */
+ if (sg[c].frequency != bat->target_freq[c])
+ sin_generator_init(&sg[c], 1.0, bat->target_freq[c],
+ bat->rate);
+ /* fill buffer for each channel */
+ sin_generator_vfill(&sg[c], sinus_f + c * frames, frames);
+ }
+
+ /* reorder samples to interleaved mode */
+ err = reorder(bat, sinus_f, frames);
+ if (err != 0)
+ return err;
+
+ /* adjust amplitude and offset of waveform */
+ err = adjust_waveform(bat, sinus_f, frames);
+ if (err != 0)
+ return err;
+
+ bat->convert_float_to_sample(sinus_f, buf, frames, bat->channels);
+
+ free(sinus_f);
+
+ return 0;
+}
--- /dev/null
+/*
+ * Copyright (C) 2015 Caleb Crome
+ * Copyright (C) 2013-2015 Intel Corporation
+ *
+ * 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.
+ *
+ */
+
+/*
+ * Here's a generic sine wave generator that will work indefinitely
+ * for any frequency.
+ *
+ * Note: the state & phasor are stored as doubles (and updated as
+ * doubles) because after a million samples the magnitude drifts a
+ * bit. If we really need floats, it can be done with periodic
+ * renormalization of the state_real+state_imag magnitudes.
+ */
+
+int sin_generator_init(struct sin_generator *, float, float, float);
+float sin_generator_next_sample(struct sin_generator *);
+void sin_generator_vfill(struct sin_generator *, float *, int);
+int generate_sine_wave(struct bat *, int, void *);
git://git.alsa-project.org / alsa-utils.git / commitdiff