From 7abf31ea821a0bbddb836adb1a63d0fec2ceee4f Mon Sep 17 00:00:00 2001
From: Leonard Kugis <leonard@kug.is>
Date: Mon, 25 Apr 2022 18:41:24 +0200
Subject: Initial commit

---
 .../instancedregions/chunkmap/ChunkWriter.java     | 108 +++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100755 src/main/java/com/encrox/instancedregions/chunkmap/ChunkWriter.java

(limited to 'src/main/java/com/encrox/instancedregions/chunkmap/ChunkWriter.java')

diff --git a/src/main/java/com/encrox/instancedregions/chunkmap/ChunkWriter.java b/src/main/java/com/encrox/instancedregions/chunkmap/ChunkWriter.java
new file mode 100755
index 0000000..398cb25
--- /dev/null
+++ b/src/main/java/com/encrox/instancedregions/chunkmap/ChunkWriter.java
@@ -0,0 +1,108 @@
+/**
+ * @author Aleksey Terzi
+ *
+ */
+
+package com.encrox.instancedregions.chunkmap;
+
+import java.io.IOException;
+
+public class ChunkWriter {
+	private byte[] data;
+	private int bitsPerBlock;
+	private int byteIndex;
+	private int bitIndex;
+	private long buffer;
+	
+	public ChunkWriter(byte[] data) {
+		this.data = data;
+	}
+	
+	public int getByteIndex() {
+		return this.byteIndex;
+	}
+	
+	public void init() {
+		this.byteIndex = 0;
+		this.bitIndex = 0;
+		this.buffer = 0;
+	}
+	
+	public void setBitsPerBlock(int bitsPerBlock) {
+		this.bitsPerBlock = bitsPerBlock;
+	}
+	
+	public void save() throws IOException {
+		writeLong();
+	}
+	
+	public void skip(int count) {
+		this.byteIndex += count;
+		this.bitIndex = 0;
+	}
+	
+	public void writeBytes(byte[] source, int index, int length) throws IOException {
+		if(this.byteIndex + length > this.data.length) {
+			throw new IOException("No space to write.");
+		}
+		
+		System.arraycopy(source, index, this.data, this.byteIndex, length);
+		
+		this.byteIndex += length;
+	}
+	
+	public void writeBlockBits(long bits) throws IOException {
+		if(this.bitIndex >= 64) {
+			writeLong();
+			this.bitIndex = 0;
+		}
+		
+		int leftBits = 64 - this.bitIndex;
+		
+		this.buffer |= bits << this.bitIndex; 
+		
+		if(leftBits >= this.bitsPerBlock) {
+			this.bitIndex += this.bitsPerBlock;
+		} else {
+			writeLong();
+			
+			this.buffer = bits >>> leftBits;
+			
+			this.bitIndex = this.bitsPerBlock - leftBits;
+		}
+	}
+	
+	private void writeLong() throws IOException {
+		if(this.byteIndex + 7 >= this.data.length) {
+			throw new IOException("No space to write.");
+		}
+		
+		this.data[this.byteIndex++] = (byte)(this.buffer >> 56);
+		this.data[this.byteIndex++] = (byte)(this.buffer >> 48);
+		this.data[this.byteIndex++] = (byte)(this.buffer >> 40);
+		this.data[this.byteIndex++] = (byte)(this.buffer >> 32);
+		this.data[this.byteIndex++] = (byte)(this.buffer >> 24);
+		this.data[this.byteIndex++] = (byte)(this.buffer >> 16);
+		this.data[this.byteIndex++] = (byte)(this.buffer >> 8);
+		this.data[this.byteIndex++] = (byte)this.buffer;
+		
+		this.buffer = 0;
+	}
+	
+	public void writeVarInt(int value) throws IOException {
+		while((value & ~0x7F) != 0) {
+            writeByte((value & 0x7F) | 0x80);
+            value >>>= 7;
+        }
+
+        writeByte(value);
+    }
+	
+	public void writeByte(int value) throws IOException {
+		if(this.byteIndex >= this.data.length) {
+			throw new IOException("No space to write.");
+		}
+		
+		this.data[this.byteIndex++] = (byte)value;
+	}
+}
-- 
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