Mercurial > hg4j
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> |
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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; + } +}