add stream copier

git-svn-id: http://trooper/svn/projects/jSite/trunk@614 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 (file)
index 0000000..1d898aa
--- /dev/null
+++ b/src/net/pterodactylus/util/io/StreamCopier.java
@@ -0,0 +1,152 @@
+/*
+ * 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;
+
+/**
+ * Copies input from an {@link InputStream} to an {@link OutputStream}.
+ * 
+ * @author <a href="mailto:droden@gmail.com">David Roden</a>
+ * @version $Id$
+ */
+public class StreamCopier {
+
+       /**
+        * The default size of the buffer.
+        */
+       private static final int BUFFER_SIZE = 64 * 1024;
+
+       /**
+        * The {@link InputStream} to read from.
+        */
+       private InputStream inputStream;
+
+       /**
+        * The {@link OutputStream} to write to.
+        */
+       private OutputStream outputStream;
+
+       /**
+        * The number of bytes to copy.
+        */
+       private long length;
+
+       /**
+        * The size of the buffer.
+        */
+       private int bufferSize;
+
+       /**
+        * Creates a new StreamCopier with the specified parameters and the default
+        * buffer size.
+        * 
+        * @param inputStream
+        *            The {@link InputStream} to read from
+        * @param outputStream
+        *            The {@link OutputStream} to write to
+        * @param length
+        *            The number of bytes to copy
+        */
+       public StreamCopier(InputStream inputStream, OutputStream outputStream, long length) {
+               this(inputStream, outputStream, length, BUFFER_SIZE);
+       }
+
+       /**
+        * Creates a new StreamCopier with the specified parameters and the default
+        * buffer size.
+        * 
+        * @param inputStream
+        *            The {@link InputStream} to read from
+        * @param outputStream
+        *            The {@link OutputStream} to write to
+        * @param length
+        *            The number of bytes to copy
+        * @param bufferSize
+        *            The number of bytes to copy at a time
+        */
+       public StreamCopier(InputStream inputStream, OutputStream outputStream, long length, int bufferSize) {
+               this.inputStream = inputStream;
+               this.outputStream = outputStream;
+               this.length = length;
+               this.bufferSize = bufferSize;
+       }
+
+       /**
+        * Copies the stream data. If the input stream is depleted before the
+        * requested number of bytes have been read an {@link EOFException} is
+        * thrown.
+        * 
+        * @throws EOFException
+        *             if the input stream is depleted before the requested number
+        *             of bytes has been read
+        * @throws IOException
+        *             if an I/O error occurs
+        */
+       public void copy() throws EOFException, IOException {
+               copy(inputStream, outputStream, length, bufferSize);
+       }
+
+       /**
+        * Copies <code>length</code> bytes from the <code>inputStream</code> to
+        * the <code>outputStream</code>.
+        * 
+        * @param inputStream
+        *            The input stream to read from
+        * @param outputStream
+        *            The output stream to write to
+        * @param length
+        *            The number of bytes to copy
+        * @throws IOException
+        *             if an I/O exception occurs
+        */
+       public static void copy(InputStream inputStream, OutputStream outputStream, long length) throws IOException {
+               copy(inputStream, outputStream, length, BUFFER_SIZE);
+       }
+
+       /**
+        * Copies <code>length</code> bytes from the <code>inputStream</code> to
+        * the <code>outputStream</code> using a buffer with the specified size
+        * 
+        * @param inputStream
+        *            The input stream to read from
+        * @param outputStream
+        *            The output stream to write to
+        * @param length
+        *            The number of bytes to copy
+        * @param bufferSize
+        *            The size of the copy buffer
+        * @throws IOException
+        *             if an I/O exception occurs
+        */
+       public static void copy(InputStream inputStream, OutputStream outputStream, long length, int bufferSize) throws IOException {
+               long remaining = length;
+               byte[] buffer = new byte[bufferSize];
+               while (remaining > 0) {
+                       int read = inputStream.read(buffer, 0, (int) Math.min(Integer.MAX_VALUE, Math.min(bufferSize, remaining)));
+                       if (read == -1) {
+                               throw new EOFException();
+                       }
+                       outputStream.write(buffer, 0, read);
+                       remaining -= read;
+               }
+       }
+
+}