Overview

ModNum and ModNumC are highly ergonomic modular arithmetic structs intended for no_std use.

ModNum objects represent a value modulo m. The value and modulo can be of any primitive integer type. Arithmetic operators include +, - (both unary and binary), *, /, pow(), and ==. Additional capabilities include computing multiplicative inverses and solving modular equations.

ModNumC objects likewise represent a value modulo M, where M is a generic constant of the usize type. Arithmetic operators include +, - (both unary and binary), *, and ==.

This library was originally developed to facilitate bidirectional navigation through fixed-size arrays at arbitrary starting points. This is facilitated by a double-ended iterator that traverses the entire ring starting at any desired value. The iterator supports both ModNum and ModNumC.

Note that ModNum and ModNumC are not designed to work with arbitrary-length integers, as they require their integer type to implement the Copy trait.

Updates

• 0.8.0:
  • Added the with() method.
  • Updated SaturatingAdd and SaturatingSub documentation.
  • Tested and updated for Rust 2021 edition.
• 0.7.1:
  • Added some more documentation tests for ModNumC.
• 0.7:
  • Added ModNumC, which uses const generics to enable compile-time checking of compatible modulo. Its functionality is a proper subset of ModNum.
  • Added MNum trait to allow ModNumIterator to work with both ModNum and ModNumC. Note: To use the .a() and .m() methods, be sure to import MNum (or just use bare_metal_modulo::*;)
• 0.6:
  • Learned that num::Saturating is deprecated.
  • Removed num::Saturating implementation.
  • Replaced by implementing num::traits::SaturatingAdd and num::traits::SaturatingSub instead.
• 0.5:
  • Implemented the num::Saturating trait.
• 0.4:
  • Added ModNum as a right-hand side option for arithmetic operators.
  • Implemented Display for ModNum objects.
• 0.3: Added division and modular exponentiation with negative exponents.
• 0.2: Added modular exponentiation and inverse.