How do you set, clear and toggle a single bit in Rust?
Like many other languages, the bitwise operators &
(bitwise AND), |
(bitwise OR), ^
(bitwise XOR) exist:
fn main() {
let mut byte: u8 = 0b0000_0000;
byte |= 0b0000_1000; // Set a bit
println!("0b{:08b}", byte);
byte &= 0b1111_0111; // Unset a bit
println!("0b{:08b}", byte);
byte ^= 0b0000_1000; // Toggle a bit
println!("0b{:08b}", byte);
}
The main difference from other languages is in bitwise NOT, which uses !
instead of ~
:
fn main() {
let mut byte: u8 = 0b0000_0000;
byte = !byte; // Flip all bits
println!("0b{:08b}", byte);
}
You can also shift bits left or right:
fn main() {
let mut byte: u8 = 0b0000_1000;
byte <<= 1; // shift left one bit
println!("0b{:08b}", byte);
byte >>= 1; // shift right one bit
println!("0b{:08b}", byte);
}
There are many other conceptual things that ultimately do bit-level manipulation that are not expressed with operators. Check out the documentation for an integer for examples. One interesting example is leading_zeros
. Here is how to rotate by a certain number of bits:
fn main() {
let mut byte: u8 = 0b1000_0000;
byte = byte.rotate_left(1); // rotate left one bit
println!("0b{:08b}", byte);
byte = byte.rotate_right(1); // rotate right one bit
println!("0b{:08b}", byte);
}
The book has some more information
Rust has both bit-twiddling operators and binary format printing (very helpful for debugging):
fn bit_twiddling(original: u8, bit: u8) {
let mask = 1 << bit;
println!(
"Original: {:b}, Set: {:b}, Cleared: {:b}, Toggled: {:b}",
original,
original | mask,
original & !mask,
original ^ mask
);
}
fn main() {
bit_twiddling(0, 3);
bit_twiddling(8, 3);
}
It also has the compound assignment variants (|=
, &=
and ^=
).
The book has some more information