typedef struct {    sp_ftbl *vals;    sp_ftbl *buf;    uint32_t id;    uint32_t pos;    uint32_t nextpos;} sp_slice; int sp_slice_create(sp_slice **p);int sp_slice_destroy(sp_slice **p);int sp_slice_init(sp_data *sp, sp_slice *p, sp_ftbl *vals, sp_ftbl *buf);int sp_slice_compute(sp_data *sp, sp_slice *p, SPFLOAT *in, SPFLOAT *out);