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Optimize `BigInt::from_biguint` and `BigInt::assign_from_slice` 

It removes useless memory allocations.
This commit is contained in:
Nicolas Kirchner 2017-08-02 22:25:21 +02:00
parent 5106fcc95a
commit cbdaf8f6f9
1 changed files with 12 additions and 12 deletions
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24
bigint/src/bigint.rs
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@ -1376,13 +1376,13 @@ impl BigInt {
///
/// The digits are in little-endian base 2^32.
#[inline]
pub fn from_biguint(sign: Sign, data: BigUint) -> BigInt {
if sign == NoSign || data.is_zero() {
return BigInt {
sign: NoSign,
data: Zero::zero(),
};
pub fn from_biguint(mut sign: Sign, mut data: BigUint) -> BigInt {
if sign == NoSign {
data.assign_from_slice(&[]);
} else if data.is_zero() {
sign = NoSign;
}
BigInt {
sign: sign,
data: data,
@ -1398,15 +1398,15 @@ impl BigInt {
/// Reinitializes a `BigInt`.
#[inline]
pub fn assign_from_slice(&mut self, sign: Sign, slice: &[BigDigit]) {
// Normalize:
let slice = &slice[..slice.iter().rposition(|&x| x != 0).map_or(0, |i| i + 1)];
if sign == NoSign || slice.len() == 0 {
if sign == NoSign {
self.data.assign_from_slice(&[]);
self.sign = NoSign;
self.data = Zero::zero();
} else {
self.sign = sign;
self.data.assign_from_slice(slice);
self.sign = match self.data.is_zero() {
true => NoSign,
false => sign,
}
}
}