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Make use of macro to avoid repetition

This commit is contained in:
Lzu Tao 2020-07-13 09:35:10 +00:00
parent a5d0c2c174
commit 34c343ac27
1 changed files with 10 additions and 23 deletions
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33
library/std/src/sys/windows/mod.rs
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@ -103,31 +103,18 @@ pub fn unrolled_find_u16s(needle: u16, haystack: &[u16]) -> Option<usize> {
// For performance reasons unfold the loop eight times.
while start.len() >= 8 {
if start[0] == needle {
return Some((start.as_ptr() as usize - ptr as usize) / 2);
}
if start[1] == needle {
return Some((start[1..].as_ptr() as usize - ptr as usize) / 2);
}
if start[2] == needle {
return Some((start[2..].as_ptr() as usize - ptr as usize) / 2);
}
if start[3] == needle {
return Some((start[3..].as_ptr() as usize - ptr as usize) / 2);
}
if start[4] == needle {
return Some((start[4..].as_ptr() as usize - ptr as usize) / 2);
}
if start[5] == needle {
return Some((start[5..].as_ptr() as usize - ptr as usize) / 2);
}
if start[6] == needle {
return Some((start[6..].as_ptr() as usize - ptr as usize) / 2);
}
if start[7] == needle {
return Some((start[7..].as_ptr() as usize - ptr as usize) / 2);
macro_rules! if_return {
($($n:literal,)+) => {
$(
if start[$n] == needle {
return Some((&start[$n] as *const u16 as usize - ptr as usize) / 2);
}
)+
}
}
if_return!(0, 1, 2, 3, 4, 5, 6, 7,);
start = &start[8..];
}