/* This code is placed in the public domain. */ #include <stdlib.h>#include "soundpipe.h" int sp_thresh_create(sp_thresh **p){    *p = malloc(sizeof(sp_thresh));    return SP_OK;} int sp_thresh_destroy(sp_thresh **p){    free(*p);    return SP_OK;} int sp_thresh_init(sp_data *sp, sp_thresh *p){    USED(sp);     /* Initalize variables here. */    p->init = 1;    p->mode = 0;    p->prev = 0;    p->thresh = 0;    return SP_OK;} int sp_thresh_compute(sp_data *sp, sp_thresh *p, SPFLOAT *in, SPFLOAT *out){    USED(sp);     if(p->init) {        *out = 0;        p->prev = *in;        p->init = 0;        return SP_OK;    }     switch((int)p->mode) {        /* input signal goes above threshold */        case 0:            *out = (*in > p->thresh && p->prev <= p->thresh);            break;         /* input signal goes below threshold */        case 1:            *out = (*in < p->thresh && p->prev >= p->thresh);            break;         /* input signal goes below or above threshold */        case 2:            *out = (*in < p->thresh && p->prev >= p->thresh) ||                (*in > p->thresh && p->prev <= p->thresh);            break;         default:            return SP_NOT_OK;    }     p->prev = *in;     return SP_OK;}