diff src/org/tmatesoft/hg/internal/ByteVector.java @ 574:88afffd39899

Improve memory consumption of HgManifest#getFileRevision(): avoid extra byte[] instances
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Tue, 16 Apr 2013 14:44:57 +0200
parents
children a62079bc422b
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/tmatesoft/hg/internal/ByteVector.java	Tue Apr 16 14:44:57 2013 +0200
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2013 TMate Software Ltd
+ *  
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * For information on how to redistribute this software under
+ * the terms of a license other than GNU General Public License
+ * contact TMate Software at support@hg4j.com
+ */
+package org.tmatesoft.hg.internal;
+
+import java.io.ByteArrayOutputStream;
+
+/**
+ * Alternative to {@link ByteArrayOutputStream}, with extra operation that prevent extra byte[] instances
+ * 
+ * @author Artem Tikhomirov
+ * @author TMate Software Ltd.
+ */
+public class ByteVector {
+	private byte[] data;
+	private int count;
+	private final int increment;
+	
+	
+	public ByteVector(int initialSize, int increment) {
+		data = new byte[initialSize];
+		this.increment = increment;
+	}
+
+	public void add(int b) {
+		if (count == data.length) {
+			byte[] newData = new byte[count + increment];
+			System.arraycopy(data, 0, newData, 0, count);
+			data = newData;
+		}
+		data[count++] = (byte) b;
+	}
+
+	public int size() {
+		return count;
+	}
+
+	public void clear() {
+		count = 0;
+	}
+	
+	public boolean equalsTo(byte[] array) {
+		if (array == null || array.length != count) {
+			return false;
+		}
+		for (int i = 0; i < count; i++) {
+			if (data[i] != array[i]) {
+				return false;
+			}
+		}
+		return true;
+	}
+	
+	/**
+	 * Copies content of this vector into destination array.
+	 * @param destination array, greater or equal to {@link #size()} of the vector
+	 */
+	public void copyTo(byte[] destination) {
+		if (destination == null || destination.length < count) {
+			throw new IllegalArgumentException();
+		}
+		System.arraycopy(data, 0, destination, 0, count);
+	}
+
+	public byte[] toByteArray() {
+		byte[] rv = new byte[count];
+		copyTo(rv);
+		return rv;
+	}
+}