ares/rust/ibig

This fork

This modifies ibig to accept a custom allocator for some operations. Specifically, any function which ends in _stack will never allocate except by calling the passed-in allocator with trait Stack. This allocator is assumed to not require deallocation, so we leak everything we allocate in that way.

Further, we leak all allocations of multi-word UBigs, even those created by non-_stack functions. This means that this repo must be used exclusively with _stack functions (or others that you know do not allocate). To allow easier integration of future upstream changes, we do not modify existing functions where possible, even though they are no longer safe to use.

It is recommended to use assert-no-alloc to verify that no allocations happen.

ibig

A big integer library with good performance.

The library implements efficient large integer arithmetic in pure Rust.

The two integer types are UBig (for unsigned integers) and IBig (for signed integers).

Modular arithmetic is supported by the module modular.

Examples

use ibig::{ibig, modular::ModuloRing, ubig, UBig};

let a = ubig!(12345678);
let b = ubig!(0x10ff);
let c = ibig!(-azz base 36);
let d: UBig = "15033211231241234523452345345787".parse()?;
let e = 2 * &b + 1;
let f = a * b.pow(10);

assert_eq!(e, ubig!(0x21ff));
assert_eq!(c.to_string(), "-14255");
assert_eq!(
    f.in_radix(16).to_string(),
    "1589bda8effbfc495d8d73c83d8b27f94954e"
);
assert_eq!(
    format!("hello {:#x}", d % ubig!(0xabcd1234134132451345)),
    "hello 0x1a7e7c487267d2658a93"
);

let ring = ModuloRing::new(&ubig!(10000));
let x = ring.from(12345);
let y = ring.from(55443);
assert_eq!(format!("{}", x - y), "6902 (mod 10000)");

Optional dependencies

• std (default): for std::error::Error.
• num-traits (default): integral traits.
• rand (default): random number generation.
• serde: serialization and deserialization.

Benchmarks

Benchmarks contains a quick benchmark of Rust big integer libraries.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.