Upstream/Minestom
1
0
Fork 0
mirror of https://github.com/Minestom/Minestom.git synced 2024-09-27 22:17:45 +02:00
Code Issues Projects Releases Wiki Activity

copy-on-write index map

Browse Source
This commit is contained in:
themode 2022-03-24 12:51:24 +01:00
parent 043c139b91
commit 2d6368f6bd
1 changed files with 16 additions and 88 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

104
src/main/java/net/minestom/server/utils/collection/IndexMap.java
View File

@ -1,111 +1,39 @@
package net.minestom.server.utils.collection;
import it.unimi.dsi.fastutil.HashCommon;
import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
import org.jetbrains.annotations.ApiStatus;
import org.jetbrains.annotations.Contract;
import org.jetbrains.annotations.NotNull;
import static it.unimi.dsi.fastutil.HashCommon.arraySize;
import static it.unimi.dsi.fastutil.HashCommon.maxFill;
// Most of the code comes from fastutil's Object2IntOpenHashMap
@ApiStatus.Internal
public final class IndexMap<K> {
private K[] key;
private int[] value;
private final Object2IntOpenHashMap<K> write = new Object2IntOpenHashMap<>();
private Object2IntOpenHashMap<K> read = copy();
private int lastIndex;
private int maxFill, size;
private final float f = 0.75f;
public IndexMap() {
final int n = arraySize(16, f);
maxFill = maxFill(n, f);
key = (K[]) new Object[n + 1];
value = new int[n + 1];
write.defaultReturnValue(-1);
}
@Contract(pure = true)
public int get(@NotNull K key) {
final int hash = HashCommon.mix(key.hashCode());
int index = getInt(key, hash);
int index = read.getInt(key);
if (index == -1) {
synchronized (this) {
index = getInt(key, hash);
if (index == -1) put(key, (index = lastIndex++), hash);
synchronized (write) {
var write = this.write;
index = write.getInt(key);
if (index == -1) {
write.put(key, (index = lastIndex++));
read = copy();
}
}
}
return index;
}
private int getInt(final K k, int hash) {
final K[] key = this.key;
final int[] value = this.value;
if (key.length != value.length)
return -1; // Race condition, continue to slow path
final int mask = key.length - 2;
K curr;
int pos;
// The starting point.
if ((curr = key[pos = hash & mask]) == null) return -1;
if (k.equals(curr)) return value[pos];
// There's always an unused entry.
while (true) {
if ((curr = key[pos = (pos + 1) & mask]) == null) return -1;
if (k.equals(curr)) return value[pos];
}
}
private void put(final K k, final int v, int hash) {
int pos = find(k, hash);
if (pos >= 0) {
value[pos] = v;
} else {
pos = -(pos + 1);
key[pos] = k;
value[pos] = v;
if (size++ >= maxFill) rehash(arraySize(size + 1, f));
}
}
private int find(final K k, int hash) {
final K[] key = this.key;
final int mask = key.length - 2;
K curr;
int pos;
// The starting point.
if ((curr = key[pos = hash & mask]) == null)
return -(pos + 1);
if (k.equals(curr)) return pos;
// There's always an unused entry.
while (true) {
if ((curr = key[pos = (pos + 1) & mask]) == null) return -(pos + 1);
if (k.equals(curr)) return pos;
}
}
private void rehash(final int newN) {
final K[] key = this.key;
final int[] value = this.value;
final int n = key.length - 1;
final int mask = newN - 1; // Note that this is used by the hashing macro
final K[] newKey = (K[]) new Object[newN + 1];
final int[] newValue = new int[newN + 1];
int i = n, pos;
for (int j = size; j-- != 0; ) {
while (((key[--i]) == null)) ;
if (!((newKey[pos = HashCommon.mix(key[i].hashCode()) & mask]) == null))
while (!((newKey[pos = (pos + 1) & mask]) == null)) ;
newKey[pos] = key[i];
newValue[pos] = value[i];
}
newValue[newN] = value[n];
this.maxFill = maxFill(n, f);
this.key = newKey;
this.value = newValue;
private Object2IntOpenHashMap<K> copy() {
var map = new Object2IntOpenHashMap<>(write);
map.defaultReturnValue(-1);
return map;
}
}