feat: some improvements on palette & bitarray

AllayMC · Dec 7, 2024 · e2edb84 · e2edb84
1 parent d843dbf
commit e2edb84
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Showing 4 changed files with 51 additions and 17 deletions.
diff --git a/server/src/main/java/org/allaymc/server/datastruct/bitarray/BitArrayVersion.java b/server/src/main/java/org/allaymc/server/datastruct/bitarray/BitArrayVersion.java
@@ -33,7 +33,7 @@ public enum BitArrayVersion {
     }
 
     public static BitArrayVersion get(int version, boolean read) {
-        for (BitArrayVersion ver : values()) {
+        for (BitArrayVersion ver : VALUES) {
             if ((!read && ver.entriesPerWord <= version) || (read && ver.bits == version)) {
                 return ver;
             }
@@ -52,24 +52,24 @@ public static BitArrayVersion forBitsCeil(int bits) {
         return null;
     }
 
-    public int getWordsForSize(int size) {
-        Preconditions.checkArgument(this != V0);
-        return GenericMath.ceil((float) size / this.entriesPerWord);
-    }
-
     public BitArray createArray(int size) {
         if (this == V0) {
             return SingletonBitArray.INSTANCE;
         }
         return this.createArray(size, new int[getWordsForSize(size)]);
     }
 
+    public int getWordsForSize(int size) {
+        Preconditions.checkArgument(this != V0);
+        return GenericMath.ceil((float) size / this.entriesPerWord);
+    }
+
     public BitArray createArray(int size, int[] words) {
-        if (this == V3 || this == V5 || this == V6) {
+        if (this == V0) {
+            return SingletonBitArray.INSTANCE;
+        } else if (this == V3 || this == V5 || this == V6) {
             // Padded palettes aren't able to use bitwise operations due to their padding.
             return new PaddedBitArray(this, size, words);
-        } else if (this == V0) {
-            return SingletonBitArray.INSTANCE;
         } else {
             return new Pow2BitArray(this, size, words);
         }

diff --git a/server/src/main/java/org/allaymc/server/datastruct/palette/Palette.java b/server/src/main/java/org/allaymc/server/datastruct/palette/Palette.java
@@ -16,8 +16,6 @@
 import java.util.List;
 
 /**
- * TODO: add tests
- *
  * @author JukeboxMC | daoge_cmd | CoolLoong
  */
 @Slf4j
@@ -69,7 +67,7 @@ public void writeToNetwork(ByteBuf byteBuf, RuntimeDataSerializer<V> serializer)
     }
 
     public void writeToStoragePersistent(ByteBuf byteBuf, PersistentDataSerializer<V> serializer) {
-        var version = isEmpty() ? BitArrayVersion.V0 : this.bitArray.version();
+        var version = oneEntryOnly() ? BitArrayVersion.V0 : this.bitArray.version();
         byteBuf.writeByte(Palette.getPaletteHeader(version, false));
 
         if (version != BitArrayVersion.V0) {
@@ -118,12 +116,12 @@ public void readFromStoragePersistent(ByteBuf byteBuf, PersistentDataDeserialize
 
     public void writeToStorageRuntime(ByteBuf byteBuf, RuntimeDataSerializer<V> serializer, Palette<V> last) {
         // FIXME: copy last flag
-//        if (last != null && last.palette.equals(this.palette)) {
+//        if (last != null && last.equals(this)) {
 //            byteBuf.writeByte(COPY_LAST_FLAG_HEADER);
 //            return;
 //        }
 
-        var version = this.isEmpty() ? BitArrayVersion.V0 : this.bitArray.version();
+        var version = this.oneEntryOnly() ? BitArrayVersion.V0 : this.bitArray.version();
         byteBuf.writeByte(Palette.getPaletteHeader(version, true));
         if (version != BitArrayVersion.V0) {
             for (int word : this.bitArray.words()) {
@@ -167,13 +165,18 @@ public void readFromStorageRuntime(ByteBuf byteBuf, RuntimeDataDeserializer<V> d
         }
     }
 
-    public boolean isEmpty() {
+    public boolean oneEntryOnly() {
         if (this.palette.size() == 1) {
             return true;
         }
-        // Do not use stream, this will be quicker
+        // The palette list may contain more than one entry,
+        // but the words are all point to the first entry.
+        // In this case, the palette is still one entry only.
         for (int word : this.bitArray.words()) {
+            // Do not use stream, this will be quicker
             if (Integer.toUnsignedLong(word) != 0L) {
+                // The word is not point to the first entry,
+                // so this palette shouldn't be empty
                 return false;
             }
         }
@@ -217,6 +220,8 @@ private int paletteIndexFor(V value) {
             var next = version.next;
             if (next != null) {
                 this.onResize(next);
+            } else {
+                throw new PaletteException("Palette have reached the max bit array version");
             }
         }
 

diff --git a/server/src/main/java/org/allaymc/server/world/chunk/ChunkSection.java b/server/src/main/java/org/allaymc/server/world/chunk/ChunkSection.java
@@ -49,7 +49,7 @@ public BiomeType getBiomeType(int x, int y, int z) {
     }
 
     public boolean isAirSection() {
-        return blockLayers[0].isEmpty() && blockLayers[0].get(0) == AIR.getDefaultState();
+        return blockLayers[0].oneEntryOnly() && blockLayers[0].get(0) == AIR.getDefaultState();
     }
 
     public void writeToNetwork(ByteBuf byteBuf) {

diff --git a/server/src/test/java/org/allaymc/server/datastruct/palette/PaletteTest.java b/server/src/test/java/org/allaymc/server/datastruct/palette/PaletteTest.java
@@ -0,0 +1,29 @@
+package org.allaymc.server.datastruct.palette;
+
+import org.allaymc.server.datastruct.bitarray.BitArrayVersion;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * @author daoge_cmd
+ */
+class PaletteTest {
+
+    @Test
+    void test() {
+        var obj0 = new Object();
+        var palette = new Palette<>(obj0, BitArrayVersion.V0);
+        assertEquals(obj0, palette.get(0));
+
+        var obj1 = new Object();
+        palette.set(1, obj1);
+        assertEquals(obj1, palette.get(1));
+
+        var obj2 = new Object();
+        palette.set(2, obj2);
+        assertEquals(obj2, palette.get(2));
+
+        // TODO: more tests
+    }
+}