diff options
| -rw-r--r-- | src/libextra/num/bigint.rs | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/src/libextra/num/bigint.rs b/src/libextra/num/bigint.rs index cb764228155..e873bf3d056 100644 --- a/src/libextra/num/bigint.rs +++ b/src/libextra/num/bigint.rs @@ -589,6 +589,12 @@ impl BigUint { } } + /// Converts this BigUint into a positively-signed BigInt. + #[inline] + pub fn to_bigint(&self) -> BigInt { + BigInt::from_biguint(Plus, self.clone()) + } + #[inline] fn shl_unit(&self, n_unit: uint) -> BigUint { if n_unit == 0 || self.is_zero() { return (*self).clone(); } @@ -1102,6 +1108,16 @@ impl BigInt { Minus => 0 } } + + /// Converts this BigInt into a BigUint. Negative BigInts are + /// converted to zero-valued BigUints. + #[inline] + pub fn to_biguint(&self) -> BigUint { + match self.sign { + Plus => self.data.clone(), + _ => Zero::zero() + } + } } #[cfg(test)] @@ -1281,6 +1297,16 @@ mod biguint_tests { assert_eq!(BigUint::new(~[0, 0, -1]).to_uint(), uint::max_value); } + #[test] + fn test_convert_to_bigint() { + fn check(n: BigUint, ans: BigInt) { + assert_eq!(n.to_bigint(), ans); + assert_eq!(n.to_bigint().to_biguint(), n); + } + check(Zero::zero(), Zero::zero()); + check(BigUint::from_uint(637), BigInt::from_uint(637)); + } + static sum_triples: &'static [(&'static [BigDigit], &'static [BigDigit], &'static [BigDigit])] = &[ @@ -1700,6 +1726,21 @@ mod bigint_tests { ).to_uint() == 0); } + #[test] + fn test_convert_to_biguint() { + fn check(n: BigInt, ans_1: BigUint, ans_2: BigInt) { + assert_eq!(n.to_biguint(), ans_1); + assert_eq!(n.to_biguint().to_bigint(), ans_2); + } + let zero: BigInt = Zero::zero(); + let unsigned_zero: BigUint = Zero::zero(); + let positive: BigInt = BigInt::from_uint(637); + let negative = -positive; + check(zero.clone(), unsigned_zero.clone(), zero.clone()); + check(positive.clone(), BigUint::from_uint(637), positive); + check(negative, unsigned_zero, zero); + } + static sum_triples: &'static [(&'static [BigDigit], &'static [BigDigit], &'static [BigDigit])] = &[ |