// MEMS mic level maths — pure logic. See mems_level.h.

#include "mems_level.h"

#include <math.h>

double mems_level_rms(const int32_t *samples, size_t n_samples) {
    if (samples == NULL || n_samples == 0) {
        return 0.0;
    }
    double sum_sq = 0.0;
    for (size_t i = 0; i < n_samples; i++) {
        double sample = (double)(samples[i] >> 8);
        sum_sq += sample * sample;
    }
    return sqrt(sum_sq / (double)n_samples);
}

double mems_level_dbfs(double rms) {
    if (rms < 1.0) {
        return MEMS_DBFS_FLOOR; // effective noise floor
    }
    double dbfs = 20.0 * log10(rms / MEMS_FULL_SCALE_24BIT);
    if (dbfs < MEMS_DBFS_FLOOR) dbfs = MEMS_DBFS_FLOOR;
    return dbfs;
}