// GCD sets z to the greatest common divisor of a and b, which must be positive
// numbers, and returns z. If x and y are not nil, GCD sets x and y such that
// z = a*x + b*y. If either a or b is not positive, GCD sets z = x = y = 0.
func (z *Int) GCD(x, y, a, b *Int) *Int {
z.doinit()
// Compatibility with math/big
if a.Cmp(intZero) <= 0 || b.Cmp(intZero) <= 0 {
z.Set(intZero)
return z
}
// allow for nil x and y
var x_ptr C.mpz_ptr = nil
if x != nil {
x.doinit()
x_ptr = x.ptr
}
var y_ptr C.mpz_ptr = nil
if y != nil {
y.doinit()
y_ptr = y.ptr
}
a.doinit()
b.doinit()
C.mpz_gcdext(z.ptr, x_ptr, y_ptr, a.ptr, b.ptr)
return z
}
// GCD sets z to the greatest common divisor of a and b, which both must
// be > 0, and returns z.
// If x and y are not nil, GCD sets x and y such that z = a*x + b*y.
// If either a or b is <= 0, GCD sets z = x = y = 0.
func (z *Int) GCD(x, y, a, b *Int) *Int {
z.doinit()
a.doinit()
b.doinit()
if a.Sign() <= 0 || b.Sign() <= 0 {
z.SetInt64(0)
if x != nil {
x.SetInt64(0)
}
if y != nil {
y.SetInt64(0)
}
} else if x == nil && y == nil {
C.mpz_gcd(&z.i[0], &a.i[0], &b.i[0])
} else {
if x != nil {
x.doinit()
} else {
x = _Int_0
}
if y != nil {
y.doinit()
} else {
y = _Int_0
}
C.mpz_gcdext(&z.i[0], &x.i[0], &y.i[0], &a.i[0], &b.i[0])
}
return z
}
// GcdInt sets d to the greatest common divisor of a and b,
// which must be positive numbers.
// If x and y are not nil, GcdInt sets x and y such that d = a*x + b*y.
// If either a or b is not positive, GcdInt sets d = x = y = 0.
func GcdInt(d, x, y, a, b *Int) {
d.doinit()
x.doinit()
y.doinit()
a.doinit()
b.doinit()
C.mpz_gcdext(&d.i[0], &x.i[0], &y.i[0], &a.i[0], &b.i[0])
}
