#include "filter.h" typedef struct samplerate { double factor; struct { filter_t lp; sample_t last_sample; double in_index; } down; struct { filter_t lp; sample_t last_sample; double in_index; } up; } samplerate_t; int init_samplerate(samplerate_t *state, double low_samplerate, double high_samplerate); int samplerate_downsample(samplerate_t *state, sample_t *samples, int input_num); int samplerate_upsample(samplerate_t *state, sample_t *input, int input_num, sample_t *output);