1 /*
2  * Copyright (C) 2010 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package java.lang;
18 
19 import android.icu.text.Transliterator;
20 import com.android.icu.util.CaseMapperNative;
21 import java.util.Locale;
22 
23 /**
24  * Performs case operations as described by http://unicode.org/reports/tr21/tr21-5.html.
25  */
26 class CaseMapper {
27     private static final char[] upperValues = "SS\u0000\u02bcN\u0000J\u030c\u0000\u0399\u0308\u0301\u03a5\u0308\u0301\u0535\u0552\u0000H\u0331\u0000T\u0308\u0000W\u030a\u0000Y\u030a\u0000A\u02be\u0000\u03a5\u0313\u0000\u03a5\u0313\u0300\u03a5\u0313\u0301\u03a5\u0313\u0342\u1f08\u0399\u0000\u1f09\u0399\u0000\u1f0a\u0399\u0000\u1f0b\u0399\u0000\u1f0c\u0399\u0000\u1f0d\u0399\u0000\u1f0e\u0399\u0000\u1f0f\u0399\u0000\u1f08\u0399\u0000\u1f09\u0399\u0000\u1f0a\u0399\u0000\u1f0b\u0399\u0000\u1f0c\u0399\u0000\u1f0d\u0399\u0000\u1f0e\u0399\u0000\u1f0f\u0399\u0000\u1f28\u0399\u0000\u1f29\u0399\u0000\u1f2a\u0399\u0000\u1f2b\u0399\u0000\u1f2c\u0399\u0000\u1f2d\u0399\u0000\u1f2e\u0399\u0000\u1f2f\u0399\u0000\u1f28\u0399\u0000\u1f29\u0399\u0000\u1f2a\u0399\u0000\u1f2b\u0399\u0000\u1f2c\u0399\u0000\u1f2d\u0399\u0000\u1f2e\u0399\u0000\u1f2f\u0399\u0000\u1f68\u0399\u0000\u1f69\u0399\u0000\u1f6a\u0399\u0000\u1f6b\u0399\u0000\u1f6c\u0399\u0000\u1f6d\u0399\u0000\u1f6e\u0399\u0000\u1f6f\u0399\u0000\u1f68\u0399\u0000\u1f69\u0399\u0000\u1f6a\u0399\u0000\u1f6b\u0399\u0000\u1f6c\u0399\u0000\u1f6d\u0399\u0000\u1f6e\u0399\u0000\u1f6f\u0399\u0000\u1fba\u0399\u0000\u0391\u0399\u0000\u0386\u0399\u0000\u0391\u0342\u0000\u0391\u0342\u0399\u0391\u0399\u0000\u1fca\u0399\u0000\u0397\u0399\u0000\u0389\u0399\u0000\u0397\u0342\u0000\u0397\u0342\u0399\u0397\u0399\u0000\u0399\u0308\u0300\u0399\u0308\u0301\u0399\u0342\u0000\u0399\u0308\u0342\u03a5\u0308\u0300\u03a5\u0308\u0301\u03a1\u0313\u0000\u03a5\u0342\u0000\u03a5\u0308\u0342\u1ffa\u0399\u0000\u03a9\u0399\u0000\u038f\u0399\u0000\u03a9\u0342\u0000\u03a9\u0342\u0399\u03a9\u0399\u0000FF\u0000FI\u0000FL\u0000FFIFFLST\u0000ST\u0000\u0544\u0546\u0000\u0544\u0535\u0000\u0544\u053b\u0000\u054e\u0546\u0000\u0544\u053d\u0000".toCharArray();
28     private static final char[] upperValues2 = "\u000b\u0000\f\u0000\r\u0000\u000e\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u000f\u0010\u0011\u0012\u0013\u0014\u0015\u0016\u0017\u0018\u0019\u001a\u001b\u001c\u001d\u001e\u001f !\"#$%&'()*+,-./0123456789:;<=>\u0000\u0000?@A\u0000BC\u0000\u0000\u0000\u0000D\u0000\u0000\u0000\u0000\u0000EFG\u0000HI\u0000\u0000\u0000\u0000J\u0000\u0000\u0000\u0000\u0000KL\u0000\u0000MN\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000OPQ\u0000RS\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000TUV\u0000WX\u0000\u0000\u0000\u0000Y".toCharArray();
29 
30     private static final char LATIN_CAPITAL_I_WITH_DOT = '\u0130';
31     private static final char GREEK_CAPITAL_SIGMA = '\u03a3';
32     private static final char GREEK_SMALL_FINAL_SIGMA = '\u03c2';
33 
34     /**
35      * Our current GC makes short-lived objects more expensive than we'd like. When that's fixed,
36      * this class should be changed so that you instantiate it with the String and its value,
37      * and count fields.
38      */
CaseMapper()39     private CaseMapper() {
40     }
41 
42     /**
43      * Implements String.toLowerCase. The original String instance is returned if nothing changes.
44      */
toLowerCase(Locale locale, String s)45     public static String toLowerCase(Locale locale, String s) {
46         // Punt hard cases to ICU4C.
47         // Note that Greek isn't a particularly hard case for toLowerCase, only toUpperCase.
48         String languageCode = locale.getLanguage();
49         if (languageCode.equals("tr") || languageCode.equals("az") || languageCode.equals("lt")) {
50             return CaseMapperNative.toLowerCase(s, locale);
51         }
52 
53         char[] newValue = null;
54         for (int i = 0, end = s.length(); i < end; ++i) {
55             char ch = s.charAt(i);
56             char newCh;
57             if (ch == LATIN_CAPITAL_I_WITH_DOT || Character.isHighSurrogate(ch)) {
58                 // Punt these hard cases.
59                 return CaseMapperNative.toLowerCase(s, locale);
60             } else if (ch == GREEK_CAPITAL_SIGMA && isFinalSigma(s, i)) {
61                 newCh = GREEK_SMALL_FINAL_SIGMA;
62             } else {
63                 newCh = Character.toLowerCase(ch);
64             }
65             if (ch != newCh) {
66                 if (newValue == null) {
67                     newValue = new char[end];
68                     s.getCharsNoCheck(0, end, newValue, 0);
69                 }
70                 newValue[i] = newCh;
71             }
72         }
73         return newValue != null ? new String(newValue) : s;
74     }
75 
76     /**
77      * True if 'index' is preceded by a sequence consisting of a cased letter and a case-ignorable
78      * sequence, and 'index' is not followed by a sequence consisting of an ignorable sequence and
79      * then a cased letter.
80      */
isFinalSigma(String s, int index)81     private static boolean isFinalSigma(String s, int index) {
82         // TODO: we don't skip case-ignorable sequences like we should.
83         // TODO: we should add a more direct way to test for a cased letter.
84         if (index <= 0) {
85             return false;
86         }
87         char previous = s.charAt(index - 1);
88         if (!(Character.isLowerCase(previous) || Character.isUpperCase(previous) || Character.isTitleCase(previous))) {
89             return false;
90         }
91         if (index + 1 >= s.length()) {
92             return true;
93         }
94         char next = s.charAt(index + 1);
95         if (Character.isLowerCase(next) || Character.isUpperCase(next) || Character.isTitleCase(next)) {
96             return false;
97         }
98         return true;
99     }
100 
101     /**
102      * Return the index of the specified character into the upperValues table.
103      * The upperValues table contains three entries at each position. These
104      * three characters are the upper case conversion. If only two characters
105      * are used, the third character in the table is \u0000.
106      * @return the index into the upperValues table, or -1
107      */
upperIndex(int ch)108     private static int upperIndex(int ch) {
109         int index = -1;
110         if (ch >= 0xdf) {
111             if (ch <= 0x587) {
112                 switch (ch) {
113                 case 0xdf: return 0;
114                 case 0x149: return 1;
115                 case 0x1f0: return 2;
116                 case 0x390: return 3;
117                 case 0x3b0: return 4;
118                 case 0x587: return 5;
119                 }
120             } else if (ch >= 0x1e96) {
121                 if (ch <= 0x1e9a) {
122                     index = 6 + ch - 0x1e96;
123                 } else if (ch >= 0x1f50 && ch <= 0x1ffc) {
124                     index = upperValues2[ch - 0x1f50];
125                     if (index == 0) {
126                         index = -1;
127                     }
128                 } else if (ch >= 0xfb00) {
129                     if (ch <= 0xfb06) {
130                         index = 90 + ch - 0xfb00;
131                     } else if (ch >= 0xfb13 && ch <= 0xfb17) {
132                         index = 97 + ch - 0xfb13;
133                     }
134                 }
135             }
136         }
137         return index;
138     }
139 
140     private static final ThreadLocal<Transliterator> EL_UPPER = new ThreadLocal<Transliterator>() {
141         @Override protected Transliterator initialValue() {
142             return Transliterator.getInstance("el-Upper");
143         }
144     };
145 
toUpperCase(Locale locale, String s, int count)146     public static String toUpperCase(Locale locale, String s, int count) {
147         String languageCode = locale.getLanguage();
148         if (languageCode.equals("tr") || languageCode.equals("az") || languageCode.equals("lt")) {
149             return CaseMapperNative.toUpperCase(s, locale);
150         }
151         if (languageCode.equals("el")) {
152             return EL_UPPER.get().transliterate(s);
153         }
154 
155         char[] output = null;
156         int i = 0;
157         for (int o = 0; o < count; o++) {
158             char ch = s.charAt(o);
159             if (Character.isHighSurrogate(ch)) {
160                 return CaseMapperNative.toUpperCase(s, locale);
161             }
162             int index = upperIndex(ch);
163             if (index == -1) {
164                 if (output != null && i >= output.length) {
165                     char[] newoutput = new char[output.length + (count / 6) + 2];
166                     System.arraycopy(output, 0, newoutput, 0, output.length);
167                     output = newoutput;
168                 }
169                 char upch = Character.toUpperCase(ch);
170                 if (output != null) {
171                     output[i++] = upch;
172                 } else if (ch != upch) {
173                     output = new char[count];
174                     i = o;
175                     s.getCharsNoCheck(0, i, output, 0);
176                     output[i++] = upch;
177                 }
178             } else {
179                 int target = index * 3;
180                 char val3 = upperValues[target + 2];
181                 if (output == null) {
182                     output = new char[count + (count / 6) + 2];
183                     i = o;
184                     s.getCharsNoCheck(0, i, output, 0);
185                 } else if (i + (val3 == 0 ? 1 : 2) >= output.length) {
186                     char[] newoutput = new char[output.length + (count / 6) + 3];
187                     System.arraycopy(output, 0, newoutput, 0, output.length);
188                     output = newoutput;
189                 }
190 
191                 char val = upperValues[target];
192                 output[i++] = val;
193                 val = upperValues[target + 1];
194                 output[i++] = val;
195                 if (val3 != 0) {
196                     output[i++] = val3;
197                 }
198             }
199         }
200         if (output == null) {
201             return s;
202         }
203         return output.length == i || output.length - i < 8 ? new String(0, i, output) : new String(output, 0, i);
204     }
205 }
206