/* ==================================================================
* UnicodeReader.java - Oct 2, 2011 9:55:32 PM
*
* Copyright 2007-2011 SolarNetwork.net Dev Team
*
* 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
* ==================================================================
* $Id$
* ==================================================================
*/
package net.solarnetwork.node.support;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PushbackInputStream;
import java.io.Reader;
/**
* Reader that can detect a Unicode BOM.
*
* Adapted from Google Data API.
*
* @author matt
* @version $Revision$
*/
public class UnicodeReader extends Reader {
private static final int BOM_SIZE = 4;
private final InputStreamReader reader;
/**
* Construct UnicodeReader.
*
* @param in Input stream.
* @param defaultEncoding Default encoding to be used if BOM is not found,
* or <code>null</code> to use system default encoding.
* @throws IOException If an I/O error occurs.
*/
public UnicodeReader(InputStream in, String defaultEncoding) throws IOException {
byte bom[] = new byte[BOM_SIZE];
String encoding;
int unread;
PushbackInputStream pushbackStream = new PushbackInputStream(in, BOM_SIZE);
int n = pushbackStream.read(bom, 0, bom.length);
// Read ahead four bytes and check for BOM marks.
if ((bom[0] == (byte) 0xEF) && (bom[1] == (byte) 0xBB) && (bom[2] == (byte) 0xBF)) {
encoding = "UTF-8";
unread = n - 3;
} else if ((bom[0] == (byte) 0xFE) && (bom[1] == (byte) 0xFF)) {
encoding = "UTF-16BE";
unread = n - 2;
} else if ((bom[0] == (byte) 0xFF) && (bom[1] == (byte) 0xFE)) {
encoding = "UTF-16LE";
unread = n - 2;
} else if ((bom[0] == (byte) 0x00) && (bom[1] == (byte) 0x00) && (bom[2] == (byte) 0xFE) && (bom[3] == (byte) 0xFF)) {
encoding = "UTF-32BE";
unread = n - 4;
} else if ((bom[0] == (byte) 0xFF) && (bom[1] == (byte) 0xFE) && (bom[2] == (byte) 0x00) && (bom[3] == (byte) 0x00)) {
encoding = "UTF-32LE";
unread = n - 4;
} else {
encoding = defaultEncoding;
unread = n;
}
// Unread bytes if necessary and skip BOM marks.
if (unread > 0) {
pushbackStream.unread(bom, (n - unread), unread);
} else if (unread < -1) {
pushbackStream.unread(bom, 0, 0);
}
// Use given encoding.
if (encoding == null) {
reader = new InputStreamReader(pushbackStream);
} else {
reader = new InputStreamReader(pushbackStream, encoding);
}
}
public String getEncoding() {
return reader.getEncoding();
}
public int read(char[] cbuf, int off, int len) throws IOException {
return reader.read(cbuf, off, len);
}
public void close() throws IOException {
reader.close();
}
}