jcommons/org.eclipse.statet.jcommons.util/src/org/eclipse/statet/jcommons/string/StringUtils.java

/*=============================================================================#
 # Copyright (c) 2021 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.jcommons.string;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;


@NonNullByDefault
public class StringUtils {
	
	
	private static final byte[] U_DIGITS= {
			'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
			'A', 'B', 'C', 'D', 'E', 'F',
	};
	
	
	/**
	 * Formats the Unicode code points in the standard U+XXXX notation.
	 * 
	 * @param cp the code point
	 * @return a string with the formatted code point
	 */
	@SuppressWarnings("deprecation")
	public static String formatCodePoint(int cp) {
		final int nDigits= Math.max(((Integer.SIZE + 7 - Integer.numberOfLeadingZeros(cp)) / 8) * 2, 4);
		final byte[] latin1= new byte[2 + nDigits];
		latin1[0]= 'U';
		latin1[1]= '+';
		int i= latin1.length;
		do {
			latin1[--i]= U_DIGITS[cp & 0xF];
			cp >>>= 4;
		} while (i > 2);
		return new String(latin1, 0, 0, latin1.length);
	}
	
	
	private StringUtils() {
	}
	
}