New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
uint: implement integer_sqrt #554
Merged
Merged
Changes from all commits
Commits
Show all changes
8 commits
Select commit
Hold shift + click to select a range
625e7f1
uint: implement integer_sqrt
ordian 2719fe2
uint: remove wrong assertion
ordian 3a59289
go brrrrrrrrrrrrrr
ordian 903c12f
we don't need to move anymore
ordian f35358a
impl-num-traits: add integer-sqrt trait support
ordian 2a0f84b
add missing test
ordian 315a3a8
fmt
ordian 2bc8de7
bump uint
ordian File filter
Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,17 @@ | ||
// Copyright 2021 Parity Technologies | ||
// | ||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | ||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | ||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | ||
// option. This file may not be copied, modified, or distributed | ||
// except according to those terms. | ||
|
||
use impl_num_traits::integer_sqrt::IntegerSquareRoot; | ||
use primitive_types::U256; | ||
|
||
#[test] | ||
fn u256_isqrt() { | ||
let x = U256::MAX; | ||
let s = x.integer_sqrt_checked().unwrap(); | ||
assert_eq!(x.integer_sqrt(), s); | ||
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,50 @@ | ||
// Copyright 2021 Parity Technologies | ||
// | ||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | ||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | ||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | ||
// option. This file may not be copied, modified, or distributed | ||
// except according to those terms. | ||
|
||
#![no_main] | ||
|
||
use libfuzzer_sys::fuzz_target; | ||
use uint::*; | ||
|
||
construct_uint! { | ||
pub struct U256(4); | ||
} | ||
|
||
fn isqrt(mut me: U256) -> U256 { | ||
let one = U256::one(); | ||
if me <= one { | ||
return me; | ||
} | ||
// the implementation is based on: | ||
// https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Binary_numeral_system_(base_2) | ||
|
||
// "bit" starts at the highest power of four <= self. | ||
let max_shift = 4 * 64 as u32 - 1; | ||
let shift: u32 = (max_shift - me.leading_zeros()) & !1; | ||
let mut bit = one << shift; | ||
let mut result = U256::zero(); | ||
while !bit.is_zero() { | ||
let x = result + bit; | ||
result >>= 1; | ||
if me >= x { | ||
me -= x; | ||
result += bit; | ||
} | ||
bit >>= 2; | ||
} | ||
result | ||
} | ||
|
||
fuzz_target!(|data: &[u8]| { | ||
if data.len() == 32 { | ||
let x = U256::from_little_endian(data); | ||
let expected = isqrt(x); | ||
let got = x.integer_sqrt(); | ||
assert_eq!(got, expected); | ||
} | ||
}); |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
So this is independent of the
num-traits
feature?There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Technically it could have been, but it's rather not useful by its own. E.g. see https://github.com/paritytech/substrate/blob/d8b3fce28513169d8ee1315dd9a4cd92d95753cc/primitives/arithmetic/src/traits.rs#L33-L51