Add Palette#fill

src/main/java/net/minestom/server/instance/palette/Palette.java

@@ -25,6 +25,8 @@ public sealed interface Palette extends Writeable permits PaletteImpl {
 
     void set(int x, int y, int z, int value);
 
+    void fill(int value);
+
     /**
      * Returns the number of entries in this palette.
      */

src/main/java/net/minestom/server/instance/palette/PaletteImpl.java

@@ -7,6 +7,8 @@ import net.minestom.server.instance.Chunk;
 import net.minestom.server.utils.binary.BinaryWriter;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Arrays;
+
 final class PaletteImpl implements Palette, Cloneable {
     private static final int[] MAGIC_MASKS;
     private static final int[] VALUES_PER_LONG;
@@ -125,6 +127,30 @@ final class PaletteImpl implements Palette, Cloneable {
         }
     }
 
+    @Override
+    public void fill(int value) {
+        final boolean placedAir = value == 0;
+        if (!placedAir) value = getPaletteIndex(value);
+        final int bitsPerEntry = this.bitsPerEntry;
+        final int valuesPerLong = VALUES_PER_LONG[bitsPerEntry];
+        long[] values = this.values;
+        if (values.length == 0) {
+            if (placedAir) {
+                // Section is empty and method is trying to place an air block, stop unnecessary computation
+                return;
+            }
+            // Initialize the section
+            this.values = values = new long[(size + valuesPerLong - 1) / valuesPerLong];
+        }
+
+        long block = 0;
+        for (int i = 0; i < valuesPerLong; i++) {
+            block |= (long) value << i * bitsPerEntry;
+        }
+        Arrays.fill(values, block);
+        this.count = maxSize();
+    }
+
     @Override
     public int size() {
         return count;

src/test/java/net/minestom/server/instance/PaletteTest.java

@@ -77,6 +77,28 @@ public class PaletteTest {
         assertEquals(4, palette.get(0, 0, 3));
     }
 
+
+    @Test
+    public void fill() {
+        var palettes = testPalettes();
+        for (Palette palette : palettes) {
+            assertEquals(0, palette.size());
+            palette.set(0, 0, 0, 5);
+            assertEquals(1, palette.size());
+            assertEquals(5, palette.get(0, 0, 0));
+            palette.fill(6);
+            assertEquals(6, palette.get(0, 0, 0));
+            assertEquals(palette.maxSize(), palette.size());
+            for (int y = 0; y < palette.dimension(); y++) {
+                for (int x = 0; x < palette.dimension(); x++) {
+                    for (int z = 0; z < palette.dimension(); z++) {
+                        assertEquals(6, palette.get(x, y, z));
+                    }
+                }
+            }
+        }
+    }
+
     @Test
     public void dimension() {
         assertThrows(Exception.class, () -> Palette.newPalette(0, 5, 3, 1));