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/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include <stddef.h>
#include <stdlib.h>
#include "cras_volume_curve.h"
/* Default to 1dB per tick.
* Volume = 100 -> 0dB.
* Volume = 0 -> -100dB. */
static long get_dBFS_default(const struct cras_volume_curve *curve,
size_t volume)
{
/* dB to cut * 100 */
return (volume - 100) * 100;
}
/* Simple curve with configurable max volume and volume step. */
struct stepped_curve {
struct cras_volume_curve curve;
long max_vol;
long step;
};
static long get_dBFS_step(const struct cras_volume_curve *curve, size_t volume)
{
const struct stepped_curve *c = (const struct stepped_curve *)curve;
return c->max_vol - (c->step * (100 - volume));
}
/*
* Exported Interface.
*/
struct cras_volume_curve *cras_volume_curve_create_default()
{
struct cras_volume_curve *curve;
curve = (struct cras_volume_curve *)calloc(1, sizeof(*curve));
if (curve != NULL)
curve->get_dBFS = get_dBFS_default;
return curve;
}
struct cras_volume_curve *cras_volume_curve_create_simple_step(
long max_volume,
long volume_step)
{
struct stepped_curve *curve;
curve = (struct stepped_curve *)calloc(1, sizeof(*curve));
if (curve == NULL)
return NULL;
curve->curve.get_dBFS = get_dBFS_step;
curve->max_vol = max_volume;
curve->step = volume_step;
return &curve->curve;
}
void cras_volume_curve_destroy(struct cras_volume_curve *curve)
{
free(curve);
}
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