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rust-bitcoin-unsafe-fast
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Fix increment of Uint256 with carry

This commit is contained in:
carolcapps 2021-03-13 15:19:43 +00:00
parent bee5e8a090
commit d52b88b525
1 changed files with 51 additions and 4 deletions
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55
src/util/uint.rs
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@ -516,13 +516,13 @@ impl Uint256 {
#[inline]
pub fn increment(&mut self) {
let &mut Uint256(ref mut arr) = self;
arr[0] += 1;
arr[0] = arr[0].wrapping_add(1);
if arr[0] == 0 {
arr[1] += 1;
arr[1] = arr[1].wrapping_add(1);
if arr[1] == 0 {
arr[2] += 1;
arr[2] = arr[2].wrapping_add(1);
if arr[2] == 0 {
arr[3] += 1;
arr[3] = arr[3].wrapping_add(1);
}
}
}
@ -689,6 +689,53 @@ mod tests {
0x4AFCFF6F0375C608u64, 0x928D92B4D7F5DF33u64]));
}
#[test]
pub fn increment_test() {
let mut val = Uint256([
0xFFFFFFFFFFFFFFFEu64,
0xFFFFFFFFFFFFFFFFu64,
0xFFFFFFFFFFFFFFFFu64,
0xEFFFFFFFFFFFFFFFu64,
]);
val.increment();
assert_eq!(
val,
Uint256([
0xFFFFFFFFFFFFFFFFu64,
0xFFFFFFFFFFFFFFFFu64,
0xFFFFFFFFFFFFFFFFu64,
0xEFFFFFFFFFFFFFFFu64,
])
);
val.increment();
assert_eq!(
val,
Uint256([
0x0000000000000000u64,
0x0000000000000000u64,
0x0000000000000000u64,
0xF000000000000000u64,
])
);
let mut val = Uint256([
0xFFFFFFFFFFFFFFFFu64,
0xFFFFFFFFFFFFFFFFu64,
0xFFFFFFFFFFFFFFFFu64,
0xFFFFFFFFFFFFFFFFu64,
]);
val.increment();
assert_eq!(
val,
Uint256([
0x0000000000000000u64,
0x0000000000000000u64,
0x0000000000000000u64,
0x0000000000000000u64,
])
);
}
#[test]
pub fn uint256_bitslice_test() {
let init = Uint256::from_u64(0xDEADBEEFDEADBEEF).unwrap();