#include "audio_gain.h"
#include <stdlib.h>
#include <stdint.h>
#include <math.h>
#include <log/log.h>

static inline int16_t float_to_short(float f)
{
    static const float scale = 1 << 15;
    return roundf(fmaxf(fminf(f * scale, scale - 1.f), -scale));
}

static inline float short_to_float(int16_t ival)
{
    static const float scale = 1. / (float)(1UL << 15);
    return ival * scale;
}

void audio_gain_process(int16_t *src, size_t count, int mute, float db_level)
{
    float db_gain;
    float value;
    size_t i;

    if (src == NULL) {
        ALOGE("audio_gain_process fail, src is NULL");
        return;
    }

    db_gain = powf(10, db_level / 20.0f); /* 10 ,20.0 are used to cauculate db */
    if (mute != 0) {
        db_gain = 0.0f;
    }
    for (i = 0; i < count; i++) {
        value = short_to_float(src[i]) * db_gain;
        src[i] = float_to_short(value);
    }
}