#include <stdlib.h>#include <math.h>#include "soundpipe.h" #ifndef max#define max(a,b) (((a) > (b)) ? (a) : (b))#endif #ifndef min#define min(a,b) (((a) < (b)) ? (a) : (b))#endif #ifndef dB/* if below -100dB, set to -100dB to prevent taking log of zero */#define dB(x) 20.0 * ((x) > 0.00001 ? log10(x) : log10(0.00001))#endif #ifndef dB2lin#define dB2lin(x)           pow( 10.0, (x) / 20.0 )#endif int sp_peaklim_create(sp_peaklim **p){    *p = malloc(sizeof(sp_peaklim));    return SP_OK;} int sp_peaklim_destroy(sp_peaklim **p){    free(*p);    return SP_OK;} int sp_peaklim_init(sp_data *sp, sp_peaklim *p){    USED(sp);     p->a1_r = 0;    p->b0_r = 1;    p->a1_a = 0;    p->b0_a = 1;    p->atk = 0.1;    p->rel = 0.1;    p->patk = -100;    p->prel = -100;    p->level = 0;    return SP_OK;} int sp_peaklim_compute(sp_data *sp, sp_peaklim *p, SPFLOAT *in, SPFLOAT *out){    SPFLOAT db_gain;    SPFLOAT gain;     /* change coefficients, if needed */     if (p->patk != p->atk) {        p->patk = p->atk;		p->a1_a = exp( -1.0 / ( p->rel * sp->sr ) );		p->b0_a = 1 - p->a1_a;    }     if (p->prel != p->rel) {        p->prel = p->rel;		p->a1_r = exp( -1.0 / ( p->rel * sp->sr ) );		p->b0_r = 1 - p->a1_r;    }      if ( fabs(*in) > p->level)        p->level += p->b0_a * ( fabs(*in) - p->level);    else        p->level += p->b0_r * ( fabs(*in) - p->level);     db_gain = min(0.0, dB(dB2lin(p->thresh)/p->level));    gain = dB2lin(db_gain);     *out = *in * gain;     return SP_OK;}