/*
* 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.tomcat.util.http;
public class HeaderUtil {
/**
* Converts an HTTP header line in byte form to a printable String. Bytes corresponding to visible ASCII characters
* will be converted to those characters. All other bytes (0x00 to 0x1F, 0x7F to 0xFF) will be represented in 0xNN
* form.
*
* @param bytes Contains an HTTP header line
* @param offset The start position of the header line in the array
* @param len The length of the HTTP header line
*
* @return A String with non-printing characters replaced by the 0xNN equivalent
*/
public static String toPrintableString(byte[] bytes, int offset, int len) {
StringBuilder result = new StringBuilder();
for (int i = offset; i < offset + len; i++) {
char c = (char) (bytes[i] & 0xFF);
if (c < 0x20 || c > 0x7E) {
result.append("0x");
result.append(Character.forDigit((c >> 4) & 0xF, 16));
result.append(Character.forDigit((c) & 0xF, 16));
} else {
result.append(c);
}
}
return result.toString();
}
private HeaderUtil() {
// Utility class. Hide default constructor.
}
}