#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <math.h>

#define PI 3.1415926535897932384626433832795

int32_t doubleToSigma(int16_t family, double value)
{
    switch (family)
    {
        case 100:
            return ((round( value * 0x800000) / 0x800000 ) * 0x800000);

        case 300:
            return ((round( value * 0x1000000) / 0x1000000 ) * 0x1000000);

        default:
            return 0;
    }
}

int main(void)
{
    float dBgain = 0.0;
    float dBoost = 1.0;
    float Q = 0.71;
    uint32_t frequency = 16;
    uint32_t sampleRate = 48000;
    double bandwidth = frequency / Q;

    double omega = (2 * PI * frequency) / sampleRate;
    double sn = sin(omega);
    double cs = cos(omega);

    double ax = pow(10, dBoost / 40);
    double alpha = sn / (2 * Q);
    double a0 = 1 + (alpha / ax);
    double gainlinear = pow(10, dBgain / 20) / a0;

    double b2 = (1 - (alpha * ax)) * gainlinear;
    double b1 = -( 2 * cs) * gainlinear;
    double b0 = (1 + (alpha * ax)) * gainlinear;
    double a2 = -(1 - (alpha / ax)) / a0;
    double a1 = (2 * cs) / a0;

    int32_t B0 = doubleToSigma(300, b0);
    int32_t B1 = doubleToSigma(300, b1);
    int32_t B2 = doubleToSigma(300, b2);
    int32_t A1 = doubleToSigma(300, a1);
    int32_t A2 = doubleToSigma(300, a2);

    printf("Gain=%.1f, Boost=%.1f, freq=%d\n", dBgain, dBoost, frequency);
    printf(" B2 = %08X \n B1 = %08X \n B0 = %08X \n A2 = %08X \n A1 = %08X \n", B2, B1, B0, A2, A1);
    printf(" B2 = %.14f\n B1 = %.14f\n B0 = %.14f\n A2 = %.14f\n A1 = %.14f\n", b2, b1, b0, a2, a1);

    printf(" BW=%0.14f\n", bandwidth);

    return 0;
}