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      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  *     http://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 
     18 package org.apache.harmony.archive.util;
     19 
     20 /**
     21  * Helpers for the archive module.
     22  */
     23 public class Util {
     24 
     25     /**
     26      * Returns whether the given source string ends with the suffix, ignoring
     27      * case and assuming that the strings are ascii encoded.
     28      *
     29      * @param source
     30      *            the string to match.
     31      * @param suffix
     32      *            the suffix to test.
     33      * @return {@code true} if the source does end with the given suffix, or
     34      *         {@code false} if not.
     35      */
     36     public static boolean asciiEndsWithIgnoreCase(String source, String suffix) {
     37         int length = suffix.length();
     38         if (length > source.length()) {
     39             return false;
     40         }
     41         int offset = source.length() - length;
     42         for (int i = 0; i < length; i++) {
     43             char c1 = source.charAt(i + offset);
     44             char c2 = suffix.charAt(i);
     45             if (c1 != c2 && toASCIIUpperCase(c1) != toASCIIUpperCase(c2)) {
     46                 return false;
     47             }
     48         }
     49         return true;
     50     }
     51 
     52     /**
     53      * Compares the given byte arrays and returns whether they are equal,
     54      * ignoring case differences and assuming they are ascii-encoded strings.
     55      *
     56      * @param buf1
     57      *            first byte array to compare.
     58      * @param buf2
     59      *            second byte array to compare.
     60      * @return the result of the comparison.
     61      */
     62     public static boolean asciiEqualsIgnoreCase(byte[] buf1, byte[] buf2) {
     63         if (buf1 == null || buf2 == null) {
     64             return false;
     65         }
     66         if (buf1 == buf2) {
     67             return true;
     68         }
     69         if (buf1.length != buf2.length) {
     70             return false;
     71         }
     72 
     73         for (int i = 0; i < buf1.length; i++) {
     74             byte b1 = buf1[i];
     75             byte b2 = buf2[i];
     76             if (b1 != b2 && toASCIIUpperCase(b1) != toASCIIUpperCase(b2)) {
     77                 return false;
     78             }
     79         }
     80         return true;
     81     }
     82 
     83     /**
     84      * Compares the given strings and returns whether they are equal, ignoring
     85      * case differences and assuming they are ascii-encoded strings.
     86      *
     87      * @param s1
     88      *            first string to compare.
     89      * @param s2
     90      *            second string to compare.
     91      * @return the result of the comparison.
     92      */
     93     public static boolean asciiEqualsIgnoreCase(String s1, String s2) {
     94         if (s1 == null || s2 == null) {
     95             return false;
     96         }
     97         if (s1 == s2) {
     98             return true;
     99         }
    100 
    101         int length = s1.length();
    102         if (length != s2.length()) {
    103             return false;
    104         }
    105 
    106         for (int i = 0; i < length; i++) {
    107             char c1 = s1.charAt(i);
    108             char c2 = s2.charAt(i);
    109             if (c1 != c2 && toASCIIUpperCase(c1) != toASCIIUpperCase(c2)) {
    110                 return false;
    111             }
    112         }
    113         return true;
    114     }
    115 
    116     private static final byte toASCIIUpperCase(byte b) {
    117         if ('a' <= b && b <= 'z') {
    118             return (byte) (b - ('a' - 'A'));
    119         }
    120         return b;
    121     }
    122 
    123     private static final char toASCIIUpperCase(char c) {
    124         if ('a' <= c && c <= 'z') {
    125             return (char) (c - ('a' - 'A'));
    126         }
    127         return c;
    128     }
    129 }
    130