// Exp sets z = x^y % m and returns z.
// If m == nil, Exp sets z = x^y.
func (z *Int) Exp(x, y, m *Int) *Int {
m.doinit()
x.doinit()
y.doinit()
z.doinit()
if m == nil {
C.mpz_pow_ui(&z.i[0], &x.i[0], C.mpz_get_ui(&y.i[0]))
} else {
C.mpz_powm(&z.i[0], &x.i[0], &y.i[0], &m.i[0])
}
return z
}
// Uint64 returns the uint64 representation of x.
// If x cannot be represented in a uint64, the result is undefined.
func (x *Int) Uint64() (y uint64) {
if !x.init {
return
}
if C.mpz_fits_ulong_p(&x.i[0]) != 0 {
return uint64(C.mpz_get_ui(&x.i[0]))
}
// Undefined result if > 64 bits
if x.BitLen() > 64 {
return
}
C.mpz_export(unsafe.Pointer(&y), nil, -1, 8, 0, 0, &x.i[0])
return
}
// Exp sets z = x^y % m and returns z. If m != nil, negative exponents are
// allowed if x^-1 mod m exists. If the inverse doesn't exist then a
// division-by-zero run-time panic occurs.
//
// If m == nil, Exp sets z = x^y for positive y and 1 for negative y.
func (z *Int) Exp(x, y, m *Int) *Int {
x.doinit()
y.doinit()
z.doinit()
if m == nil || m.Cmp(intZero) == 0 {
if y.Sign() == -1 {
z := NewInt(1)
return z
}
C.mpz_pow_ui(z.ptr, x.ptr, C.mpz_get_ui(y.ptr))
} else {
m.doinit()
C.mpz_powm(z.ptr, x.ptr, y.ptr, m.ptr)
}
return z
}
// Exp sets z = x**y mod |m| (i.e. the sign of m is ignored), and returns z.
// If y <= 0, the result is 1; if m == nil or m == 0, z = x**y.
// See Knuth, volume 2, section 4.6.3.
func (z *Int) Exp(x, y, m *Int) *Int {
x.doinit()
y.doinit()
z.doinit()
if y.Sign() <= 0 {
z.SetInt64(1)
return z
}
if m == nil || m.Sign() == 0 {
C.mpz_pow_ui(&z.i[0], &x.i[0], C.mpz_get_ui(&y.i[0]))
} else {
m.doinit()
C.mpz_powm(&z.i[0], &x.i[0], &y.i[0], &m.i[0])
}
return z
}
// Uint32 returns the uint32 representation of z, if z fits into a uint32.
// If z is too big then the least significant bits that do fit are returned.
// The sign of z is ignored, only the absolute value is used.
//
// NB This is not part of big.Int
func (z *Int) Uint32() uint32 {
z.doinit()
return uint32(C.mpz_get_ui(&z.i[0]))
}
// Uint64 returns the uint64 representation of x. If x cannot be
// represented in an uint64, the result is undefined.
func (z *Int) Uint64() uint64 {
if !z.init {
return 0
}
return uint64(C.mpz_get_ui(z.ptr))
}