/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.io;
import java.io.Serializable;
/**
* Byte Order Mark (BOM) representation - see {@link org.apache.commons.io.input.BOMInputStream}.
*
* @see org.apache.commons.io.input.BOMInputStream
* @see <a href="http://en.wikipedia.org/wiki/Byte_order_mark">Wikipedia: Byte Order Mark</a>
* @see <a href="http://www.w3.org/TR/2006/REC-xml-20060816/#sec-guessing">W3C: Autodetection of Character Encodings
* (Non-Normative)</a>
* @version $Id: ByteOrderMark.java 1347571 2012-06-07 11:13:53Z sebb $
* @since 2.0
*/
public class ByteOrderMark implements Serializable {
private static final long serialVersionUID = 1L;
/** UTF-8 BOM */
public static final ByteOrderMark UTF_8 = new ByteOrderMark("UTF-8", 0xEF, 0xBB, 0xBF);
/** UTF-16BE BOM (Big-Endian) */
public static final ByteOrderMark UTF_16BE = new ByteOrderMark("UTF-16BE", 0xFE, 0xFF);
/** UTF-16LE BOM (Little-Endian) */
public static final ByteOrderMark UTF_16LE = new ByteOrderMark("UTF-16LE", 0xFF, 0xFE);
/**
* UTF-32BE BOM (Big-Endian)
* @since 2.2
*/
public static final ByteOrderMark UTF_32BE = new ByteOrderMark("UTF-32BE", 0x00, 0x00, 0xFE, 0xFF);
/**
* UTF-32LE BOM (Little-Endian)
* @since 2.2
*/
public static final ByteOrderMark UTF_32LE = new ByteOrderMark("UTF-32LE", 0xFF, 0xFE, 0x00, 0x00);
private final String charsetName;
private final int[] bytes;
/**
* Construct a new BOM.
*
* @param charsetName The name of the charset the BOM represents
* @param bytes The BOM's bytes
* @throws IllegalArgumentException if the charsetName is null or
* zero length
* @throws IllegalArgumentException if the bytes are null or zero
* length
*/
public ByteOrderMark(String charsetName, int... bytes) {
if (charsetName == null || charsetName.length() == 0) {
throw new IllegalArgumentException("No charsetName specified");
}
if (bytes == null || bytes.length == 0) {
throw new IllegalArgumentException("No bytes specified");
}
this.charsetName = charsetName;
this.bytes = new int[bytes.length];
System.arraycopy(bytes, 0, this.bytes, 0, bytes.length);
}
/**
* Return the name of the {@link java.nio.charset.Charset} the BOM represents.
*
* @return the character set name
*/
public String getCharsetName() {
return charsetName;
}
/**
* Return the length of the BOM's bytes.
*
* @return the length of the BOM's bytes
*/
public int length() {
return bytes.length;
}
/**
* The byte at the specified position.
*
* @param pos The position
* @return The specified byte
*/
public int get(int pos) {
return bytes[pos];
}
/**
* Return a copy of the BOM's bytes.
*
* @return a copy of the BOM's bytes
*/
public byte[] getBytes() {
byte[] copy = new byte[bytes.length];
for (int i = 0; i < bytes.length; i++) {
copy[i] = (byte)bytes[i];
}
return copy;
}
/**
* Indicates if this BOM's bytes equals another.
*
* @param obj The object to compare to
* @return true if the bom's bytes are equal, otherwise
* false
*/
@Override
public boolean equals(Object obj) {
if (!(obj instanceof ByteOrderMark)) {
return false;
}
ByteOrderMark bom = (ByteOrderMark)obj;
if (bytes.length != bom.length()) {
return false;
}
for (int i = 0; i < bytes.length; i++) {
if (bytes[i] != bom.get(i)) {
return false;
}
}
return true;
}
/**
* Return the hashcode for this BOM.
*
* @return the hashcode for this BOM.
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
int hashCode = getClass().hashCode();
for (int b : bytes) {
hashCode += b;
}
return hashCode;
}
/**
* Provide a String representation of the BOM.
*
* @return the length of the BOM's bytes
*/
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append(getClass().getSimpleName());
builder.append('[');
builder.append(charsetName);
builder.append(": ");
for (int i = 0; i < bytes.length; i++) {
if (i > 0) {
builder.append(",");
}
builder.append("0x");
builder.append(Integer.toHexString(0xFF & bytes[i]).toUpperCase());
}
builder.append(']');
return builder.toString();
}
}