Bitmatch

The bitmatch crate provides tools for packing and unpacking integers as sequences of bits. Supports #![no_std].

Examples

Using #[bitmatch] with a let unpacks the bits into separate single-character variables for each letter you use.

Using bitpack!() re-packs the bits from those single-character variables into a single integer.

use bitmatch::bitmatch;

#[bitmatch]
fn interleave(n: u8) -> u8 {
    #[bitmatch]
    let "xxxx_yyyy" = n;
    bitpack!("xyxy_xyxy")
}

fn main() {
    assert_eq!(interleave(0xF0), 0xAA);
}

You can use #[bitmatch] on a match as well, and it will ensure that the literal portions match, and bind the variable portions.

use bitmatch::bitmatch;
#[bitmatch]
fn decode(inst: u8) -> String {
    #[bitmatch]
    match inst {
        "00oo_aabb" => format!("Op {}, {}, {}", o, a, b),
        "0100_aaii" => format!("Val {}, {}", a, i),
        "01??_????" => format!("Invalid"),
        "10ii_aabb" => format!("Ld {}, {}, {}", a, b, i),
        "11ii_aabb" => format!("St {}, {}, {}", a, b, i),
    }
}