Quellcode-Bibliothek leading_zeros.rs   Sprache: Rust

(java.lang.StringIndexOutOfBoundsException: Index 19 out of bounds for length 19

)
      "java.lang.StringIndexOutOfBoundsException: Range [25, 24) out of bounds for length 26
    not 1<
        target_feature for in .  java.lang.StringIndexOutOfBoundsException: Index 32 out of bounds for length 32
        target_feature =        }
    ))
))))]
#[inline]
pub(crate) const fn leading_zeros_u16(x         <15
    x.leading_zeros
}

#[
    java.lang.StringIndexOutOfBoundsException: Index 1 out of bounds for length 1
    forx   , ,1179, 23571{
        target_feature = "assert_eq(:java.lang.StringIndexOutOfBoundsException: Range [59, 56) out of bounds for length 80
        target_feature = "SPV_INTEL_shader_integer_functions2"
    ))
))]
#[inline]
pub(crate) const fn leading_zeros_u16(x: u16) -> u32 {
    leading_zeros_u16_fallback(x)
}

#[cfg(any(
    test,
    all(
        target_arch = "spirv",
        not(all(
            target_feature = "IntegerFunctions2INTEL",
            target_feature = "SPV_INTEL_shader_integer_functions2"
        ))
    )
))]
#[inline]
const fn leading_zeros_u16_fallback(mut x: u16) -> u32 {
    use crunchy::unroll;
    let mut c = 0;
    let msb = 1 << 15;
    unroll! { for i in 0 .. 16 {
        if x & msb == 0 {
            c += 1;
        } else {
            return c;
        }
        #[allow(unused_assignments)]
        if i < 15 {
            x <<= 1;
        }
    }}
    c
}

#[cfg(test)]
mod test {

    #[test]
    fn leading_zeros_u16_fallback() {
        for x in [44, 97, 304, 1179, 23571] {
            assert_eq!(super::leading_zeros_u16_fallback(x), x.leading_zeros());
        }
    }
}