mirror of
https://github.com/urbit/ares.git
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92 lines
2.9 KiB
Markdown
92 lines
2.9 KiB
Markdown
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# This fork
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This modifies ibig to accept a custom allocator for some operations.
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Specifically, any function which ends in `_stack` will never allocate
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except by calling the passed-in allocator with trait `Stack`. This
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allocator is assumed to *not* require deallocation, so we leak
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everything we allocate in that way.
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Further, we leak *all* allocations of multi-word `UBig`s, even those created by
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non-`_stack` functions. This means that this repo *must* be used
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exclusively with `_stack` functions (or others that you know do not
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allocate). To allow easier integration of future upstream changes, we
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do not modify existing functions where possible, even though they are no
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longer safe to use.
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It is recommended to use
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[assert-no-alloc](https://github.com/Windfisch/rust-assert-no-alloc) to
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verify that no allocations happen.
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# ibig
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[](https://crates.io/crates/ibig)
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[](https://docs.rs/ibig)
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[](https://github.com/tczajka/ibig-rs/actions/workflows/tests.yml)
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A big integer library with good performance.
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The library implements efficient large integer arithmetic in pure Rust.
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The two integer types are `UBig` (for unsigned integers) and `IBig` (for signed integers).
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Modular arithmetic is supported by the module `modular`.
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## Examples
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```rust
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use ibig::{ibig, modular::ModuloRing, ubig, UBig};
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let a = ubig!(12345678);
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let b = ubig!(0x10ff);
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let c = ibig!(-azz base 36);
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let d: UBig = "15033211231241234523452345345787".parse()?;
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let e = 2 * &b + 1;
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let f = a * b.pow(10);
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assert_eq!(e, ubig!(0x21ff));
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assert_eq!(c.to_string(), "-14255");
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assert_eq!(
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f.in_radix(16).to_string(),
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"1589bda8effbfc495d8d73c83d8b27f94954e"
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);
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assert_eq!(
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format!("hello {:#x}", d % ubig!(0xabcd1234134132451345)),
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"hello 0x1a7e7c487267d2658a93"
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);
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let ring = ModuloRing::new(&ubig!(10000));
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let x = ring.from(12345);
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let y = ring.from(55443);
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assert_eq!(format!("{}", x - y), "6902 (mod 10000)");
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```
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## Optional dependencies
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* `std` (default): for `std::error::Error`.
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* `num-traits` (default): integral traits.
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* `rand` (default): random number generation.
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* `serde`: serialization and deserialization.
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## Benchmarks
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[Benchmarks](https://github.com/tczajka/bigint-benchmark-rs) contains a quick benchmark of
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Rust big integer libraries.
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## License
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Licensed under either of
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* Apache License, Version 2.0
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([LICENSE-APACHE](LICENSE-APACHE) or https://www.apache.org/licenses/LICENSE-2.0)
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* MIT license
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([LICENSE-MIT](LICENSE-MIT) or https://opensource.org/licenses/MIT)
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at your option.
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## Contribution
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Unless you explicitly state otherwise, any contribution intentionally submitted
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for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
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dual licensed as above, without any additional terms or conditions.
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