typedef struct  {    SPFLOAT delay;    uint32_t bufpos;    uint32_t bufsize;    SPFLOAT *buf;} sp_reverse; int sp_reverse_create(sp_reverse **p);int sp_reverse_destroy(sp_reverse **p);int sp_reverse_init(sp_data *sp, sp_reverse *p, SPFLOAT delay);int sp_reverse_compute(sp_data *sp, sp_reverse *p, SPFLOAT *in, SPFLOAT *out);