From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Spottedleaf Date: Wed, 15 Apr 2020 18:23:28 -0700 Subject: [PATCH] Optimise ArraySetSorted#removeIf Remove iterator allocation and ensure the call is always O(n) diff --git a/src/main/java/net/minecraft/server/ArraySetSorted.java b/src/main/java/net/minecraft/server/ArraySetSorted.java index 85f799a713db0c822d46b689010f9f6bd43f5280..7db6b5850b91588eb4d91f0d7e8b5dbbcb95b7cb 100644 --- a/src/main/java/net/minecraft/server/ArraySetSorted.java +++ b/src/main/java/net/minecraft/server/ArraySetSorted.java @@ -10,8 +10,8 @@ import java.util.NoSuchElementException; public class ArraySetSorted extends AbstractSet { private final Comparator a; - private T[] b; - private int c; + private T[] b; private final T[] getBackingArray() { return this.b; } // Paper - OBFHELPER + private int c; private final int getSize() { return this.c; } private final void setSize(int value) { this.c = value; } // Paper - OBFHELPER private ArraySetSorted(int i, Comparator comparator) { this.a = comparator; @@ -22,6 +22,42 @@ public class ArraySetSorted extends AbstractSet { } } + // Paper start - optimise removeIf + @Override + public boolean removeIf(java.util.function.Predicate filter) { + // prev. impl used an iterator, which could be n^2 and creates garbage + int i = 0, len = this.getSize(); + T[] backingArray = this.getBackingArray(); + + for (;;) { + if (i >= len) { + return false; + } + if (!filter.test(backingArray[i])) { + ++i; + continue; + } + break; + } + + // we only want to write back to backingArray if we really need to + + int lastIndex = i; // this is where new elements are shifted to + + for (; i < len; ++i) { + T curr = backingArray[i]; + if (!filter.test(curr)) { // if test throws we're screwed + backingArray[lastIndex++] = curr; + } + } + + // cleanup end + Arrays.fill(backingArray, lastIndex, len, null); + this.setSize(lastIndex); + return true; + } + // Paper end - optimise removeIf + public static > ArraySetSorted a(int i) { return new ArraySetSorted<>(i, (Comparator)Comparator.naturalOrder()); // Paper - decompile fix }