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pub fn hash(s: &str) -> u32 {
let mut h = s.len() as u32;
let mut a: u32;
let mut b: u32;
let len = s.len();
let s = s.as_ptr();
unsafe {
match len {
0 => return 0,
1..=3 => {
a = *s as _;
h ^= *s.add(len - 1) as u32;
b = *s.add(len >> 1) as _;
h ^= b; h = h.wrapping_sub(b.rotate_left(14));
}
_ => {
a = s.cast::<u32>().read_unaligned();
h ^= s.add(len - 4).cast::<u32>().read_unaligned();
b = s.add((len >> 1).wrapping_sub(2)).cast::<u32>()
.read_unaligned();
h ^= b; h = h.wrapping_sub(b.rotate_left(14));
b += s.add((len >> 2).wrapping_sub(1)).cast::<u32>()
.read_unaligned();
}
}
}
a ^= h; a = a.wrapping_sub(h.rotate_left(11));
b ^= a; b = b.wrapping_sub(a.rotate_left(25));
h ^= b; h = h.wrapping_sub(b.rotate_left(16));
h
}
