/* This code is placed in the public domain. */ #include <stdlib.h>#include <math.h>#include "soundpipe.h"#include "openlpc.h" int sp_lpc_create(sp_lpc **lpc){    *lpc = malloc(sizeof(sp_lpc));    return SP_OK;} int sp_lpc_destroy(sp_lpc **lpc){    sp_lpc *plpc;    plpc = *lpc;    free(plpc->e);    free(plpc->d);    free(plpc->out);    free(plpc->in);    free(*lpc);    return SP_OK;} int sp_lpc_init(sp_data *sp, sp_lpc *lpc, int framesize){    int i;    lpc->counter = 0;    lpc->clock = 0;    lpc->block = 4;    lpc->samp = 0;    lpc->mode = 0;    lpc->framesize = framesize;    openlpc_sr(sp->sr / lpc->block);     lpc->d = calloc(1, openlpc_get_decoder_state_size());    lpc->e = calloc(1, openlpc_get_encoder_state_size());     lpc->in = calloc(1, sizeof(short) * framesize);    lpc->out = calloc(1, sizeof(short) * framesize);     init_openlpc_decoder_state(lpc->d, framesize);    init_openlpc_encoder_state(lpc->e, framesize);     for (i = 0; i < framesize; i++) {        lpc->in[i] = 0;        lpc->out[i] = 0;        if(i < 7) lpc->data[i] = 0;    }    return SP_OK;} int sp_lpc_compute(sp_data *sp, sp_lpc *lpc, SPFLOAT *in, SPFLOAT *out){    int i;     if (lpc->clock == 0) {        if (lpc->counter == 0) {            if (lpc->mode == 0) {                openlpc_encode(lpc->in, lpc->data, lpc->e);            } else {                for (i = 0; i < 7; i++) {                    lpc->y[i] =                        lpc->smooth*lpc->y[i] +                        (1-lpc->smooth)*lpc->ft->tbl[i];                    lpc->data[i] = 255 * lpc->y[i];                }            }            openlpc_decode(sp, lpc->data, lpc->out, lpc->d);        }         if (lpc->mode == 0) lpc->in[lpc->counter] = *in * 32767;        lpc->samp = lpc->out[lpc->counter] / 32767.0;         lpc->counter = (lpc->counter + 1) % lpc->framesize;    }      lpc->clock = (lpc->clock + 1) % lpc->block;    *out = lpc->samp;     return SP_OK;} int sp_lpc_synth(sp_data *sp, sp_lpc *lpc, sp_ftbl *ft){    int i;    int sr;    sr = sp->sr;     sr = sr / 4;    sr = sr / lpc->framesize;    lpc->ft = ft;    lpc->mode = 1;    for (i = 0; i < 7; i++) lpc->y[i] = 0;    lpc->smooth = exp(-1.0 / (0.01 * sr));    return SP_OK;}