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hack for now: map uint hashes into a u32, which helps x86_64 perf.

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This commit is contained in:
Niko Matsakis 2011-12-06 15:55:11 -08:00
parent aa99bfa170
commit 66355607da
1 changed files with 12 additions and 8 deletions
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20
src/libstd/map.rs
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@ -137,21 +137,25 @@ fn mk_hashmap<copy K, copy V>(hasher: hashfn<K>, eqer: eqfn<K>)
// is always a power of 2), so that all buckets are probed for a
// fixed key.
fn hashl(n: uint, _nbkts: uint) -> uint { ret (n >>> 16u) * 2u + 1u; }
fn hashr(n: uint, _nbkts: uint) -> uint { ret 0x0000_ffff_u & n; }
fn hash(h: uint, nbkts: uint, i: uint) -> uint {
ret (hashl(h, nbkts) * i + hashr(h, nbkts)) % nbkts;
fn hashl(n: u32) -> u32 { ret (n >>> 16u32) * 2u32 + 1u32; }
fn hashr(n: u32) -> u32 { ret 0x0000_ffff_u32 & n; }
fn hash(h: u32, nbkts: uint, i: uint) -> uint {
ret ((hashl(h) as uint) * i + (hashr(h) as uint)) % nbkts;
}
fn to_u64(h: uint) -> u32 {
ret (h as u32) ^ ((h >>> 16u) as u32);
}
/**
* We attempt to never call this with a full table. If we do, it
* will fail.
*/
fn insert_common<copy K, copy V>(hasher: hashfn<K>, eqer: eqfn<K>,
bkts: [mutable bucket<K, V>],
nbkts: uint, key: K, val: V) -> bool {
let i: uint = 0u;
let h: uint = hasher(key);
let h = to_u64(hasher(key));
while i < nbkts {
let j: uint = hash(h, nbkts, i);
alt bkts[j] {
@ -171,7 +175,7 @@ fn mk_hashmap<copy K, copy V>(hasher: hashfn<K>, eqer: eqfn<K>)
bkts: [mutable bucket<K, V>],
nbkts: uint, key: K) -> option::t<V> {
let i: uint = 0u;
let h: uint = hasher(key);
let h = to_u64(hasher(key));
while i < nbkts {
let j: uint = hash(h, nbkts, i);
alt bkts[j] {
@ -244,7 +248,7 @@ fn mk_hashmap<copy K, copy V>(hasher: hashfn<K>, eqer: eqfn<K>)
}
fn remove(key: K) -> option::t<V> {
let i: uint = 0u;
let h: uint = hasher(key);
let h = to_u64(hasher(key));
while i < nbkts {
let j: uint = hash(h, nbkts, i);
alt bkts[j] {