File syn_filter.h

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#ifndef SYN_FILTER_H
#define SYN_FILTER_H

#include "../util/syn_qmath.h"

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/* ── Configuration ──────────────────────────────────────────────────────── */

#ifndef SYN_FILTER_MAX_WINDOW
#define SYN_FILTER_MAX_WINDOW 32
#endif

/* ── Moving Average ─────────────────────────────────────────────────────── */

typedef struct {
    int16_t buf[SYN_FILTER_MAX_WINDOW]; 
    int32_t sum;                        
    uint8_t window;                     
    uint8_t count;                      
    uint8_t idx;                        
} SYN_FilterMA;

void syn_filter_ma_init(SYN_FilterMA *f, uint8_t window);

int16_t syn_filter_ma_update(SYN_FilterMA *f, int16_t sample);

void syn_filter_ma_reset(SYN_FilterMA *f);

/* ── Exponential Moving Average ─────────────────────────────────────────── */

typedef struct {
    int32_t value; 
    uint8_t alpha; 
    bool primed;   
} SYN_FilterEMA;

void syn_filter_ema_init(SYN_FilterEMA *f, uint8_t alpha);

int16_t syn_filter_ema_update(SYN_FilterEMA *f, int16_t sample);

void syn_filter_ema_reset(SYN_FilterEMA *f);

/* ── Median Filter ──────────────────────────────────────────────────────── */

typedef struct {
    int16_t buf[SYN_FILTER_MAX_WINDOW]; 
    uint8_t window;                     
    uint8_t count;                      
    uint8_t idx;                        
} SYN_FilterMedian;

void syn_filter_median_init(SYN_FilterMedian *f, uint8_t window);

int16_t syn_filter_median_update(SYN_FilterMedian *f, int16_t sample);

void syn_filter_median_reset(SYN_FilterMedian *f);

/* ── FIR Filter ─────────────────────────────────────────────────────────── */

typedef struct {
    const q16_t *taps; 
    q16_t *history;    
    uint16_t num_taps; 
    uint16_t head;     
} SYN_FilterFIR;

void syn_filter_fir_init(SYN_FilterFIR *f, const q16_t *taps, q16_t *history, uint16_t num_taps);

q16_t syn_filter_fir_update(SYN_FilterFIR *f, q16_t sample);

void syn_filter_fir_reset(SYN_FilterFIR *f);

#ifdef __cplusplus
}
#endif

#endif /* SYN_FILTER_H */