/*
 *  Copyright 2008 biaoping.yin
 *
 *  Licensed 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.frameworkset.web.util;

/**
 * <p>Title: JavaScriptUtils.java</p> 
 * <p>Description: </p>
 * <p>bboss workgroup</p>
 * <p>Copyright (c) 2008</p>
 * @Date 2010-10-10
 * @author biaoping.yin
 * @version 1.0
 */
public class JavaScriptUtils {
	
	/**
	 * Turn special characters into escaped characters conforming to JavaScript.
	 * Handles complete character set defined in HTML 4.01 recommendation.
	 * @param input the input string
	 * @return the escaped string
	 */
	public static String javaScriptEscape(String input) {
		if (input == null) {
			return input;
		}

		StringBuffer filtered = new StringBuffer(input.length());
		char prevChar = '\u0000';
		char c;
		for (int i = 0; i < input.length(); i++) {
			c = input.charAt(i);
			if (c == '"') {
				filtered.append("\\\"");
			}
			else if (c == '\'') {
				filtered.append("\\'");
			}
			else if (c == '\\') {
				filtered.append("\\\\");
			}
			else if (c == '/') {
				filtered.append("\\/");
			}
			else if (c == '\t') {
				filtered.append("\\t");
			}
			else if (c == '\n') {
				if (prevChar != '\r') {
					filtered.append("\\n");
				}
			}
			else if (c == '\r') {
				filtered.append("\\n");
			}
			else if (c == '\f') {
				filtered.append("\\f");
			}
			else {
				filtered.append(c);
			}
			prevChar = c;

		}
		return filtered.toString();
	}

}
