1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.codec.binary;
18
19 /**
20 * <p>
21 * Operations on {@link CharSequence} that are {@code null} safe.
22 * </p>
23 * <p>
24 * Copied from Apache Commons Lang r1586295 on April 10, 2014 (day of 3.3.2 release).
25 * </p>
26 *
27 * @see CharSequence
28 * @since 1.10
29 */
30 public class CharSequenceUtils {
31
32 /**
33 * Green implementation of regionMatches.
34 *
35 * <p>
36 * Note: This function differs from the current implementation in Apache Commons Lang where the input indices are not valid. It is only used within this
37 * package.
38 * </p>
39 *
40 * @param cs the {@code CharSequence} to be processed.
41 * @param ignoreCase whether or not to be case-insensitive.
42 * @param thisStart the index to start on the {@code cs} CharSequence.
43 * @param substring the {@code CharSequence} to be looked for.
44 * @param start the index to start on the {@code substring} CharSequence.
45 * @param length character length of the region.
46 * @return whether the region matched.
47 */
48 static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, final int thisStart,
49 final CharSequence substring, final int start, final int length) {
50 if (cs instanceof String && substring instanceof String) {
51 return ((String) cs).regionMatches(ignoreCase, thisStart, (String) substring, start, length);
52 }
53 int index1 = thisStart;
54 int index2 = start;
55 int tmpLen = length;
56 while (tmpLen-- > 0) {
57 final char c1 = cs.charAt(index1++);
58 final char c2 = substring.charAt(index2++);
59 if (c1 == c2) {
60 continue;
61 }
62 if (!ignoreCase) {
63 return false;
64 }
65 // The same check as in String.regionMatches():
66 if (Character.toUpperCase(c1) != Character.toUpperCase(c2) &&
67 Character.toLowerCase(c1) != Character.toLowerCase(c2)) {
68 return false;
69 }
70 }
71 return true;
72 }
73
74 /**
75 * Consider private.
76 *
77 * @deprecated Will be private in the next major version.
78 */
79 @Deprecated
80 public CharSequenceUtils() {
81 // empty
82 }
83 }