From 51795ccbd1347ac9ad0f28e2a537c4b8186c3253 Mon Sep 17 00:00:00 2001
From: themode <themode@outlook.fr>
Date: Fri, 7 Jan 2022 01:35:43 +0100
Subject: [PATCH] Avoid second map operation

---
 .../server/instance/palette/PaletteImpl.java         | 12 ++++++------
 .../net/minestom/server/instance/PaletteTest.java    |  7 +++++++
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/main/java/net/minestom/server/instance/palette/PaletteImpl.java b/src/main/java/net/minestom/server/instance/palette/PaletteImpl.java
index 88be64f50..282a43be3 100644
--- a/src/main/java/net/minestom/server/instance/palette/PaletteImpl.java
+++ b/src/main/java/net/minestom/server/instance/palette/PaletteImpl.java
@@ -61,6 +61,7 @@ final class PaletteImpl implements Palette, Cloneable {
         this.paletteToValueList.add(0);
         this.valueToPaletteMap = new Int2IntOpenHashMap(1);
         this.valueToPaletteMap.put(0, 0);
+        this.valueToPaletteMap.defaultReturnValue(-1);
     }
 
     @Override
@@ -362,18 +363,17 @@ final class PaletteImpl implements Palette, Cloneable {
 
     private int getPaletteIndex(int value) {
         if (!hasPalette) return value;
-        final int lookup = valueToPaletteMap.getOrDefault(value, (short) -1);
-        if (lookup != -1) return lookup;
-
+        final int lastPaletteIndex = this.lastPaletteIndex;
         if (lastPaletteIndex >= maxPaletteSize(bitsPerEntry)) {
             // Palette is full, must resize
             resize(bitsPerEntry + bitsIncrement);
             return getPaletteIndex(value);
         }
-        final int paletteIndex = lastPaletteIndex++;
+        final int lookup = valueToPaletteMap.putIfAbsent(value, lastPaletteIndex);
+        if (lookup != -1) return lookup;
+        this.lastPaletteIndex = lastPaletteIndex + 1;
         this.paletteToValueList.add(value);
-        this.valueToPaletteMap.put(value, paletteIndex);
-        return paletteIndex;
+        return lastPaletteIndex;
     }
 
     int getSectionIndex(int x, int y, int z) {
diff --git a/src/test/java/net/minestom/server/instance/PaletteTest.java b/src/test/java/net/minestom/server/instance/PaletteTest.java
index 7312b2a4d..8edfe9b65 100644
--- a/src/test/java/net/minestom/server/instance/PaletteTest.java
+++ b/src/test/java/net/minestom/server/instance/PaletteTest.java
@@ -14,6 +14,13 @@ import static org.junit.jupiter.api.Assertions.*;
 
 public class PaletteTest {
 
+    @Test
+    public void singlePlacement() {
+        var palette = Palette.blocks();
+        palette.set(0, 0, 1, 1);
+        assertEquals(1, palette.get(0, 0, 1));
+    }
+
     @Test
     public void placement() {
         var palettes = testPalettes();