Optimise ArraySetSorted#removeIf
Remove iterator allocation and ensure the call is always O(n)
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@ -0,0 +1,68 @@
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From f9c59df3e2db59fafe5e156b5c2e1929cc185218 Mon Sep 17 00:00:00 2001
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From: Spottedleaf <Spottedleaf@users.noreply.github.com>
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Date: Wed, 15 Apr 2020 18:23:28 -0700
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Subject: [PATCH] Optimise ArraySetSorted#removeIf
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Remove iterator allocation and ensure the call is always O(n)
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diff --git a/src/main/java/net/minecraft/server/ArraySetSorted.java b/src/main/java/net/minecraft/server/ArraySetSorted.java
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index 85f799a71..7db6b5850 100644
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--- a/src/main/java/net/minecraft/server/ArraySetSorted.java
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+++ b/src/main/java/net/minecraft/server/ArraySetSorted.java
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@@ -10,8 +10,8 @@ import java.util.NoSuchElementException;
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public class ArraySetSorted<T> extends AbstractSet<T> {
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private final Comparator<T> a;
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- private T[] b;
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- private int c;
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+ private T[] b; private final T[] getBackingArray() { return this.b; } // Paper - OBFHELPER
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+ private int c; private final int getSize() { return this.c; } private final void setSize(int value) { this.c = value; } // Paper - OBFHELPER
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private ArraySetSorted(int i, Comparator<T> comparator) {
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this.a = comparator;
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@@ -22,6 +22,42 @@ public class ArraySetSorted<T> extends AbstractSet<T> {
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}
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}
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+ // Paper start - optimise removeIf
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+ @Override
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+ public boolean removeIf(java.util.function.Predicate<? super T> filter) {
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+ // prev. impl used an iterator, which could be n^2 and creates garbage
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+ int i = 0, len = this.getSize();
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+ T[] backingArray = this.getBackingArray();
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+
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+ for (;;) {
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+ if (i >= len) {
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+ return false;
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+ }
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+ if (!filter.test(backingArray[i])) {
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+ ++i;
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+ continue;
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+ }
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+ break;
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+ }
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+
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+ // we only want to write back to backingArray if we really need to
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+
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+ int lastIndex = i; // this is where new elements are shifted to
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+
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+ for (; i < len; ++i) {
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+ T curr = backingArray[i];
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+ if (!filter.test(curr)) { // if test throws we're screwed
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+ backingArray[lastIndex++] = curr;
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+ }
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+ }
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+
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+ // cleanup end
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+ Arrays.fill(backingArray, lastIndex, len, null);
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+ this.setSize(lastIndex);
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+ return true;
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+ }
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+ // Paper end - optimise removeIf
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+
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public static <T extends Comparable<T>> ArraySetSorted<T> a(int i) {
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return new ArraySetSorted<>(i, (Comparator)Comparator.naturalOrder()); // Paper - decompile fix
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}
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--
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2.26.0
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