#ifndef _THREEFISH_H
#define _THREEFISH_H

typedef unsigned long long W64;
extern W64 key_const;

typedef struct {
  W64 key[4];
  W64 tweak[2];
  int outlen;
} skein_t;

#define rl(x, b) (((x) << ((b) & 63)) | ((x) >> ((64-(b)) & 63)))
#define rr(x, b) (((x) >> ((b) & 63)) | ((x) << ((64-(b)) & 63)))

typedef enum {
  T_KEY = 0,
  T_CONFIG = 4,
  T_PERSONALIZATION = 8,
  T_PUBKEY = 12,
  T_KEYIDENTIFIER = 16,
  T_NONCE = 20,
  T_MSG = 48,
  T_OUT = 63
} UBIType;

void encrypt256(W64* key, W64 t0, W64 t1, W64* in, W64* out);
void decrypt256(W64* key, W64 t0, W64 t1, W64* in, W64* out);

/* note that here outlen is in *bits* */
void skein256_init(skein_t* ctx, W64* key, W64 outlen);
/* firstlast & 1 if we're starting a new type, firstlast & 2 if it's the last update */
void skein256_update(skein_t* ctx, int firstlast, UBIType type, W64 len, W64* data);
void skein256_output(skein_t* ctx, int from, int to, W64* out);

inline void init_tweak(UBIType type, W64* t);
inline void mk_config_tweak(W64* t);
inline void set_type(UBIType type, W64* t);
inline void set_first(unsigned char first, W64* t);
inline void set_last(unsigned char last, W64* t);
inline void add_bytes(W64 bytes, W64* t);

#endif