1# num-bigint
2
3[![crate](https://img.shields.io/crates/v/num-bigint.svg)](https://crates.io/crates/num-bigint)
4[![documentation](https://docs.rs/num-bigint/badge.svg)](https://docs.rs/num-bigint)
5[![minimum rustc 1.31](https://img.shields.io/badge/rustc-1.31+-red.svg)](https://rust-lang.github.io/rfcs/2495-min-rust-version.html)
6[![build status](https://github.com/rust-num/num-bigint/workflows/master/badge.svg)](https://github.com/rust-num/num-bigint/actions)
7
8Big integer types for Rust, `BigInt` and `BigUint`.
9
10## Usage
11
12Add this to your `Cargo.toml`:
13
14```toml
15[dependencies]
16num-bigint = "0.4"
17```
18
19## Features
20
21The `std` crate feature is enabled by default, and is mandatory before Rust
221.36 and the stabilized `alloc` crate.  If you depend on `num-bigint` with
23`default-features = false`, you must manually enable the `std` feature yourself
24if your compiler is not new enough.
25
26### Random Generation
27
28`num-bigint` supports the generation of random big integers when the `rand`
29feature is enabled. To enable it include rand as
30
31```toml
32rand = "0.8"
33num-bigint = { version = "0.4", features = ["rand"] }
34```
35
36Note that you must use the version of `rand` that `num-bigint` is compatible
37with: `0.8`.
38
39## Releases
40
41Release notes are available in [RELEASES.md](RELEASES.md).
42
43## Compatibility
44
45The `num-bigint` crate is tested for rustc 1.31 and greater.
46
47## Alternatives
48
49While `num-bigint` strives for good performance in pure Rust code, other
50crates may offer better performance with different trade-offs.  The following
51table offers a brief comparison to a few alternatives.
52
53| Crate             | License        | Min rustc | Implementation | Features |
54| :---------------  | :------------- | :-------- | :------------- | :------- |
55| **`num-bigint`**  | MIT/Apache-2.0 | 1.31      | pure rust | dynamic width, number theoretical functions |
56| [`awint`]         | MIT/Apache-2.0 | 1.66      | pure rust | fixed width, heap or stack, concatenation macros |
57| [`bnum`]          | MIT/Apache-2.0 | 1.61      | pure rust | fixed width, parity with Rust primitives including floats |
58| [`crypto-bigint`] | MIT/Apache-2.0 | 1.57      | pure rust | fixed width, stack only |
59| [`ibig`]          | MIT/Apache-2.0 | 1.49      | pure rust | dynamic width, number theoretical functions |
60| [`rug`]           | LGPL-3.0+      | 1.65      | bundles [GMP] via [`gmp-mpfr-sys`] | all the features of GMP, MPFR, and MPC |
61
62[`awint`]: https://crates.io/crates/awint
63[`bnum`]: https://crates.io/crates/bnum
64[`crypto-bigint`]: https://crates.io/crates/crypto-bigint
65[`ibig`]: https://crates.io/crates/ibig
66[`rug`]: https://crates.io/crates/rug
67
68[GMP]: https://gmplib.org/
69[`gmp-mpfr-sys`]: https://crates.io/crates/gmp-mpfr-sys
70
71## License
72
73Licensed under either of
74
75 * [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
76 * [MIT license](http://opensource.org/licenses/MIT)
77
78at your option.
79
80### Contribution
81
82Unless you explicitly state otherwise, any contribution intentionally submitted
83for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
84dual licensed as above, without any additional terms or conditions.
85