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Panda Core is the core module of Panda Framework, it contains commonly used utility classes similar to apache-commons.
There is a newer version: 1.8.0
package panda.io;

import java.io.Serializable;
import java.nio.charset.Charset;

/**
 * Byte Order Mark (BOM) representation
 * 
 * @see Wikipedia: Byte Order Mark
 * @see W3C: Autodetection of
 *      Character Encodings (Non-Normative)
 */
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)
	 */
	public static final ByteOrderMark UTF_32BE = new ByteOrderMark("UTF-32BE", 0x00, 0x00, 0xFE, 0xFF);

	/**
	 * UTF-32LE BOM (Little-Endian)
	 */
	public static final ByteOrderMark UTF_32LE = new ByteOrderMark("UTF-32LE", 0xFF, 0xFE, 0x00, 0x00);

	/**
	 * ALL UNICODE BOM
	 */
	public static final ByteOrderMark[] ALL = {
		UTF_8, UTF_16BE, UTF_16LE, UTF_32BE, UTF_32LE
	};

	/**
	 * Unicode BOM character; external form depends on the encoding.
	 * 
	 * @see Byte Order Mark (BOM) FAQ
	 */
	public static final char UTF_BOM = '\uFEFF';

	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(final String charsetName, final 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 charset of the {@link java.nio.charset.Charset} the BOM represents.
	 * 
	 * @return the character
	 */
	public Charset getCharset() {
		return Charset.forName(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(final int pos) {
		return bytes[pos];
	}

	/**
	 * Return a copy of the BOM's bytes.
	 * 
	 * @return a copy of the BOM's bytes
	 */
	public byte[] getBytes() {
		final 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(final Object obj) {
		if (!(obj instanceof ByteOrderMark)) {
			return false;
		}
		final 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 (final 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() {
		final 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();
	}

}