Fixed-point numbers

The fixed crate provides fixed-point numbers. Currently it uses the typenum crate for the fractional bit count; it is planned to move to const generics when they are implemented by the Rust compiler.

The crate provides the following types:

• FixedI8 is a signed eight-bit fixed-point number,
• FixedI16 is a signed 16-bit fixed-point number,
• FixedI32 is a signed 32-bit fixed-point number,
• FixedI64 is a signed 64-bit fixed-point number,
• FixedI128 is a signed 128-bit fixed-point number,
• FixedU8 is an unsigned eight-bit fixed-point number,
• FixedU16 is an unsigned 16-bit fixed-point number,
• FixedU32 is an unsigned 32-bit fixed-point number,
• FixedU64 is an unsigned 64-bit fixed-point number, and
• FixedU128 is an unsigned 128-bit fixed-point number.

All fixed-point numbers can have Frac fractional bits, where Frac can have any value from 0 up to and including the size of the number in bits. When Frac is 0, the fixed-point number behaves like an integer. When Frac is equal to the number of bits, the value of the fixed-point number lies in the range −0.5 ≤ x < 0.5 for signed fixed-point numbers, and in the range 0 ≤ x < 1 for unsigned fixed-point numbers.

What’s new

Version 0.1.1 news (unreleased)

• New static methods int_bits and frac_bits were added.
• New methods from_int, to_int, to_int_ceil, to_int_floor and to_int_round were added.
• New methods int and frac were added.
• Support for multiplication and division by integers was added.

Version 0.1.0 news (2018-08-10)

• Unsigned constants provided by the typenum crate are now used for the number of fractional bits.
• Many methods and trait implementations available for primitive integers are now also supported by the fixed-point numbers.

Other releases

Details on other releases can be found in RELEASES.md.

Using the fixed crate

The fixed crate is available on crates.io. To use it in your crate, add it as a dependency inside Cargo.toml:

[dependencies]
fixed = "0.1.0"

You also need to declare it by adding this to your crate root (usually lib.rs or main.rs):

extern crate fixed;

License

This crate is free software: you can redistribute it and/or modify it under the terms of either

• the Apache License, Version 2.0 or
• the MIT License

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 License, Version 2.0, shall be dual licensed as above, without any additional terms or conditions.