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| 1 | /* | ||
| 2 | * Copyright (c) 2002, 2004, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package sun.misc; | ||
| 27 | |||
| 28 | import java.util.Comparator; | ||
| 29 | |||
| 30 | /** Implements a locale and case insensitive comparator suitable for | ||
| 31 | strings that are known to only contain ASCII characters. Some | ||
| 32 | tables internal to the JDK contain only ASCII data and are using | ||
| 33 | the "generalized" java.lang.String case-insensitive comparator | ||
| 34 | which converts each character to both upper and lower case. */ | ||
| 35 | |||
| 36 | public class ASCIICaseInsensitiveComparator implements Comparator<String> { | ||
| 37 | public static final Comparator<String> CASE_INSENSITIVE_ORDER = | ||
| 38 | new ASCIICaseInsensitiveComparator(); | ||
| 39 | |||
| 40 | public int compare(String s1, String s2) { | ||
| 41 | int n1=s1.length(), n2=s2.length(); | ||
| 42 | int minLen = n1 < n2 ? n1 : n2; | ||
| 43 | for (int i=0; i < minLen; i++) { | ||
| 44 | char c1 = s1.charAt(i); | ||
| 45 | char c2 = s2.charAt(i); | ||
| 46 | assert c1 <= '\u007F' && c2 <= '\u007F'; | ||
| 47 | if (c1 != c2) { | ||
| 48 | c1 = (char)toLower(c1); | ||
| 49 | c2 = (char)toLower(c2); | ||
| 50 | if (c1 != c2) { | ||
| 51 | return c1 - c2; | ||
| 52 | } | ||
| 53 | } | ||
| 54 | } | ||
| 55 | return n1 - n2; | ||
| 56 | } | ||
| 57 | |||
| 58 | /** | ||
| 59 | * A case insensitive hash code method to go with the case insensitive | ||
| 60 | * compare() method. | ||
| 61 | * | ||
| 62 | * Returns a hash code for this ASCII string as if it were lower case. | ||
| 63 | * | ||
| 64 | * returns same answer as:<p> | ||
| 65 | * <code>s.toLowerCase(Locale.US).hashCode();</code><p> | ||
| 66 | * but does not allocate memory (it does NOT have the special | ||
| 67 | * case Turkish rules). | ||
| 68 | * | ||
| 69 | * @param s a String to compute the hashcode on. | ||
| 70 | * @return a hash code value for this object. | ||
| 71 | */ | ||
| 72 | public static int lowerCaseHashCode(String s) { | ||
| 73 | int h = 0; | ||
| 74 | int len = s.length(); | ||
| 75 | |||
| 76 | for (int i = 0; i < len; i++) { | ||
| 77 | h = 31*h + toLower(s.charAt(i)); | ||
| 78 | } | ||
| 79 | |||
| 80 | return h; | ||
| 81 | } | ||
| 82 | |||
| 83 | /* If java.util.regex.ASCII ever becomes public or sun.*, use its code instead:*/ | ||
| 84 | static boolean isLower(int ch) { | ||
| 85 | return ((ch-'a')|('z'-ch)) >= 0; | ||
| 86 | } | ||
| 87 | |||
| 88 | static boolean isUpper(int ch) { | ||
| 89 | return ((ch-'A')|('Z'-ch)) >= 0; | ||
| 90 | } | ||
| 91 | |||
| 92 | static int toLower(int ch) { | ||
| 93 | return isUpper(ch) ? (ch + 0x20) : ch; | ||
| 94 | } | ||
| 95 | |||
| 96 | static int toUpper(int ch) { | ||
| 97 | return isLower(ch) ? (ch - 0x20) : ch; | ||
| 98 | } | ||
| 99 | } | ||