Commit 3f4fbf90 authored by jD91mZM2's avatar jD91mZM2
Browse files

Merge branch 'feature/optimise-memcmp' into 'master'

Optimise `memcmp` for speed

See merge request !167
parents 91675b5b 8e2b7c11
Pipeline #1458 failed with stages
in 9 minutes and 17 seconds
......@@ -73,14 +73,32 @@ pub unsafe extern "C" fn memchr(s: *const c_void, c: c_int, n: usize) -> *mut c_
#[no_mangle]
pub unsafe extern "C" fn memcmp(s1: *const c_void, s2: *const c_void, n: usize) -> c_int {
let mut i = 0;
while i < n {
let a = *(s1 as *const u8).offset(i as isize);
let b = *(s2 as *const u8).offset(i as isize);
if a != b {
return a as i32 - b as i32;
let (div, rem) = (n / mem::size_of::<usize>(), n % mem::size_of::<usize>());
let mut a = s1 as *const usize;
let mut b = s2 as *const usize;
for _ in 0..div {
if *a != *b {
for i in 0..mem::size_of::<usize>() {
let c = *(a as *const u8).offset(i as isize);
let d = *(b as *const u8).offset(i as isize);
if c != d {
return c as c_int - d as c_int;
}
}
unreachable!()
}
i += 1;
a = a.offset(1);
b = b.offset(1);
}
let mut a = a as *const u8;
let mut b = b as *const u8;
for _ in 0..rem {
if *a != *b {
return a as c_int - b as c_int;
}
a = a.offset(1);
b = b.offset(1);
}
0
}
......
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