ref: d8ddc90c497260a1f22cfbbc72c58ba1434eb366
dir: /h/in.h/
typedef struct { FILE *fp; } sp_in; int sp_in_create(sp_in **p); int sp_in_destroy(sp_in **p); int sp_in_init(sp_data *sp, sp_in *p); int sp_in_compute(sp_data *sp, sp_in *p, SPFLOAT *in, SPFLOAT *out);