#include <stdio.h>

#include <gmp.h>

#define uint unsigned int
#define u8 unsigned char

#include <string>
using namespace std;

class MPI {
    // FIXME: Make this protected
public:
    mpz_t n;

public:
    class MPIError { };
    MPI () { mpz_init (n); }
    MPI (uint i) { mpz_init (n) ; mpz_set_ui (n, i); }
    MPI (const char *c){ mpz_init (n) ; if (mpz_set_str (n, c, 0) == -1)
	throw MPIError ();
    }
    MPI (const char *c, int base) {
	mpz_init (n); if (mpz_set_str (n, c, base) == -1)
	    throw MPIError ();
    }
    MPI (const MPI &m) { mpz_init_set (n, m.n); }
    ~MPI () { mpz_clear (n); }

    void set_to (uint i) { mpz_set_ui (n, i); }
    void set_to (const char *c, int base) {
	if (mpz_set_str (n, c, base) == -1) throw MPIError (); }
    
    void set_to (const MPI &m) { mpz_set (n, m.n); }
    void set_to_binary (const u8 *, uint);
    void add (uint i) { mpz_add_ui (n, n, i); }
    void add (const MPI &m) { mpz_add (n, n, m.n); }
    void sub (uint i) { mpz_sub_ui (n, n, i); }
    void sub (const MPI &m) { mpz_sub (n, n, m.n); }

    void modpow (uint i, const MPI &m) { mpz_powm_ui (n, n, i, m.n); }
    void modpow (const MPI &m, const MPI &m2){
	mpz_powm (n, n, m.n, m2.n);
    }

    void power (uint i) {
	mpz_pow_ui (n, n, i);
    }

    int prime_test (const int rounds) { return mpz_probab_prime_p (n, rounds); }
    
    void mod (const MPI &m) { mpz_mod (n, n, m.n); }
    void mul (const MPI &m) { mpz_mul (n, n, m.n); }
    void div (const MPI &m, MPI &r) { mpz_tdiv_qr (n, r.n, n, m.n); }
    bool equ_to (uint i) { return mpz_cmp_ui (n, i) == 0; }
    bool equ_to (const MPI &m) { return mpz_cmp (n, m.n) == 0; }
    void and_op (const MPI &m) { mpz_and (n, n, m.n); }

    int compareTo (const MPI &m) { return mpz_cmp (n, m.n); }
    int comp (const MPI &m) { return mpz_cmp (n, m.n) == 0; }
    void modinvert (const MPI &m) { mpz_invert (n, n, m.n); }
    bool lessthan (const MPI &m) { return (mpz_cmp (n, m.n) < 0); }
	
    int bitsize () const { return mpz_sizeinbase (n, 2); }
    int bytesize () const { return mpz_sizeinbase (n, 0x100); }
    int size () const { return mpz_size (n); }
    string get_string (uint);

    int opgp (char *buf, char **obuf);
    int opgp (u8 *buf, u8 **obuf) { return opgp ((char *) buf, (char **) obuf); }
    int bin_dump (u8 *, uint);
    void get_buf (u8 *, uint);
};

int
main() {
	MPI p("0xFFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08"
"8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B"
"302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9"
"A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6"
"49286651ECE65381FFFFFFFFFFFFFFFF");
	MPI one("0x1");
	MPI two("0x2");

	printf("p is prime returns %d\n", p.prime_test(256));

	MPI twopone(p);
	twopone.add(p);
	twopone.add(one);

	printf("2p+1 is prime returns %d\n", twopone.prime_test(256));

	MPI halfpmo(p);
	MPI remainder;
	halfpmo.sub(one);
	halfpmo.div(two, remainder);
	
	printf("(p-1)/2 is prime returns %d\n", halfpmo.prime_test(256));

	return 0;
}