#integer #big-int #big-integer #numbers


Big integer types that have a small on-stack representation for small values. Uses num-bigint internally.

10 releases (3 stable)

1.1.0 Dec 13, 2020
0.7.0 Apr 5, 2020
0.6.0 Mar 29, 2020

#1694 in Data structures


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Two types, Uint and Int, like smallvec for big integers. Anything that fits in 32 bits stays on the stack. Numbers that don't fit are stored in a Box<num_bigint::BigUint> / Box<num_bigint::BigInt>.

On 64-bit architectures, by default we use unsafe to compress the types to 8 bytes, exploiting pointer alignment. This behavior is triggered by the unsafe-opt feature, which is enabled by default.

Implemented traits

Most important numeric traits have been implemented. Here are some that aren't yet; pull requests are welcome!

  • Bit operations
  • num_traits::Num, num_traits::Signed, num_traits::Unsigned, num_integer::Integer, num_integer::Roots, std::iter::Product, std::iter::Sum, num_traits::pow::Pow
  • Other methods implemented directly on BigInt, BigUint
  • Implement num_bigint::{ToBigInt, ToBigUint}


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


~12K SLoC