/// Returns the zero-based position of the most significant set bit (MSB)
/// in an unsigned 32-bit integer.
///
/// Examples:
/// 1 -> Some(0)
/// 2 -> Some(1)
/// 8 -> Some(3)
/// 15 -> Some(3)
///
/// Returns:
/// None if the value is 0 because no bits are set.
fn msb_position(value: u32) -> Option<u32> {
if value == 0 {
return None;
}
Some(u32::BITS - 1 - value.leading_zeros())
}
fn main() {
let test_values: [u32; 7] = [
0,
1,
2,
8,
15,
0x1234,
0x8000_0000,
];
for value in test_values {
match msb_position(value) {
Some(position) => {
println!(
"Value: {}, MSB position: {}",
value, position
);
}
None => {
println!(
"Value: {}, no bits are set",
value
);
}
}
}
}
/*
run:
Value: 0, no bits are set
Value: 1, MSB position: 0
Value: 2, MSB position: 1
Value: 8, MSB position: 3
Value: 15, MSB position: 3
Value: 4660, MSB position: 12
Value: 2147483648, MSB position: 31
*/
