From: David ‘Bombe’ Roden <bombe@pterodactylus.net>
Date: Sat, 5 Apr 2008 21:04:46 +0000 (+0000)
Subject: add improved stream copier
X-Git-Url: https://git.pterodactylus.net/?a=commitdiff_plain;h=a689a44df847282b2ea40e917f178976e7c80682;p=jSite2.git

add improved stream copier

git-svn-id: http://trooper/svn/projects/jSite/trunk@616 c3eda9e8-030b-0410-8277-bc7414b0a119
---

diff --git a/src/net/pterodactylus/util/io/StreamCopier.java b/src/net/pterodactylus/util/io/StreamCopier.java
new file mode 100644
index 0000000..d1d0b11
--- /dev/null
+++ b/src/net/pterodactylus/util/io/StreamCopier.java
@@ -0,0 +1,124 @@
+/*
+ * jSite2 - StreamCopier.java -
+ * Copyright © 2008 David Roden
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+package net.pterodactylus.util.io;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * Helper class that copies bytes from an {@link InputStream} to an
+ * {@link OutputStream}.
+ * 
+ * @author <a href="mailto:dr@ina-germany.de">David Roden</a>
+ * @version $Id$
+ */
+public class StreamCopier {
+
+	/** Default buffer size is 64k. */
+	private static final int DEFAULT_BUFFER_SIZE = 1 << 16;
+
+	/** The current buffer size. */
+	private static int bufferSize = DEFAULT_BUFFER_SIZE;
+
+	/**
+	 * Sets the buffer size for following transfers.
+	 * 
+	 * @param bufferSize
+	 *            The new buffer size
+	 */
+	public static void setBufferSize(int bufferSize) {
+		StreamCopier.bufferSize = bufferSize;
+	}
+
+	/**
+	 * Copies <code>length</code> bytes from the source input stream to the
+	 * destination output stream. If <code>length</code> is <code>-1</code>
+	 * as much bytes as possible will be copied (i.e. until
+	 * {@link InputStream#read()} returns <code>-1</code> to signal the end of
+	 * the stream).
+	 * 
+	 * @param source
+	 *            The input stream to read from
+	 * @param destination
+	 *            The output stream to write to
+	 * @param length
+	 *            The number of bytes to copy
+	 * @throws IOException
+	 *             if an I/O error occurs
+	 */
+	public static void copy(InputStream source, OutputStream destination, long length) throws IOException {
+		long remaining = length;
+		byte[] buffer = new byte[bufferSize];
+		int read = 0;
+		while ((remaining == -1) || (remaining > 0)) {
+			read = source.read(buffer, 0, ((remaining > bufferSize) || (remaining == -1)) ? bufferSize : (int) remaining);
+			if (read == -1) {
+				if (length == -1) {
+					return;
+				}
+				throw new EOFException("stream reached eof");
+			}
+			destination.write(buffer, 0, read);
+			remaining -= read;
+		}
+	}
+
+	/**
+	 * Copies as much bytes as possible (i.e. until {@link InputStream#read()}
+	 * returns <code>-1</code>) from the source input stream to the
+	 * destination output stream.
+	 * 
+	 * @param source
+	 *            The input stream to read from
+	 * @param destination
+	 *            The output stream to write to
+	 * @throws IOException
+	 *             if an I/O error occurs
+	 */
+	public static void copy(InputStream source, OutputStream destination) throws IOException {
+		copy(source, destination, -1);
+	}
+
+	/**
+	 * Finds the length of the input stream by reading until
+	 * {@link InputStream#read(byte[])} returns <code>-1</code>.
+	 * 
+	 * @param source
+	 *            The input stream to measure
+	 * @return The length of the input stream in bytes
+	 * @throws IOException
+	 *             if an I/O error occurs
+	 */
+	public static long findLength(InputStream source) throws IOException {
+		long length = 0;
+		byte[] buffer = new byte[bufferSize];
+		int read = 0;
+		while (read != -1) {
+			read = source.read(buffer);
+			if (read != -1) {
+				length += read;
+			}
+		}
+		return length;
+	}
+
+}