001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.codec.binary; 018 019/** 020 * <p> 021 * Operations on {@link CharSequence} that are {@code null} safe. 022 * </p> 023 * <p> 024 * Copied from Apache Commons Lang r1586295 on April 10, 2014 (day of 3.3.2 release). 025 * </p> 026 * 027 * @see CharSequence 028 * @since 1.10 029 */ 030public class CharSequenceUtils { 031 032 /** 033 * Green implementation of regionMatches. 034 * 035 * <p>Note: This function differs from the current implementation in Apache Commons Lang 036 * where the input indices are not valid. It is only used within this package. 037 * 038 * @param cs 039 * the {@code CharSequence} to be processed 040 * @param ignoreCase 041 * whether or not to be case insensitive 042 * @param thisStart 043 * the index to start on the {@code cs} CharSequence 044 * @param substring 045 * the {@code CharSequence} to be looked for 046 * @param start 047 * the index to start on the {@code substring} CharSequence 048 * @param length 049 * character length of the region 050 * @return whether the region matched 051 */ 052 static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, final int thisStart, 053 final CharSequence substring, final int start, final int length) { 054 if (cs instanceof String && substring instanceof String) { 055 return ((String) cs).regionMatches(ignoreCase, thisStart, (String) substring, start, length); 056 } 057 int index1 = thisStart; 058 int index2 = start; 059 int tmpLen = length; 060 061 while (tmpLen-- > 0) { 062 final char c1 = cs.charAt(index1++); 063 final char c2 = substring.charAt(index2++); 064 065 if (c1 == c2) { 066 continue; 067 } 068 069 if (!ignoreCase) { 070 return false; 071 } 072 073 // The same check as in String.regionMatches(): 074 if (Character.toUpperCase(c1) != Character.toUpperCase(c2) && 075 Character.toLowerCase(c1) != Character.toLowerCase(c2)) { 076 return false; 077 } 078 } 079 080 return true; 081 } 082}