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Make FNV64 function generic

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This commit is contained in:
Truman Kilen 2024-05-31 12:15:24 -05:00
parent b13c073a4d
commit 91861bb78f
1 changed files with 12 additions and 8 deletions
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20
repak/src/pak.rs
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@ -599,12 +599,7 @@ fn generate_path_hash_index<W: Write>(
) -> Result<(), super::Error> {
writer.write_u32::<LE>(entries.len() as u32)?;
for (path, offset) in entries.keys().zip(offsets) {
let utf16le_path = path
.to_lowercase()
.encode_utf16()
.flat_map(|c| c.to_le_bytes())
.collect::<Vec<_>>();
let path_hash = fnv64(&utf16le_path, path_hash_seed);
let path_hash = fnv64_path(path, path_hash_seed);
writer.write_u64::<LE>(path_hash)?;
writer.write_u32::<LE>(*offset)?;
}
@ -614,17 +609,26 @@ fn generate_path_hash_index<W: Write>(
Ok(())
}
fn fnv64(data: &[u8], offset: u64) -> u64 {
fn fnv64<I>(data: I, offset: u64) -> u64
where
I: IntoIterator<Item = u8>,
{
const OFFSET: u64 = 0xcbf29ce484222325;
const PRIME: u64 = 0x00000100000001b3;
let mut hash = OFFSET.wrapping_add(offset);
for &b in data {
for b in data.into_iter() {
hash ^= b as u64;
hash = hash.wrapping_mul(PRIME);
}
hash
}
fn fnv64_path(path: &str, offset: u64) -> u64 {
let lower = path.to_lowercase();
let data = lower.encode_utf16().flat_map(u16::to_le_bytes);
fnv64(data, offset)
}
fn split_path_child(path: &str) -> Option<(&str, &str)> {
if path == "/" || path.is_empty() {
None