1 /*
2 * Copyright (c) 2016, 2019, 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 java.util.regex;
27
28 import java.util.Objects;
29
30 final class Grapheme {
31
32 /**
33 * Determines if there is an extended grapheme cluster boundary between two
34 * continuing characters {@code cp1} and {@code cp2}.
35 * <p>
36 * See Unicode Standard Annex #29 Unicode Text Segmentation for the specification
37 * for the extended grapheme cluster boundary rules
38 * <p>
39 * Note: this method does not take care of stateful breaking.
40 */
41 static boolean isBoundary(int cp1, int cp2) {
42 return rules[getType(cp1)][getType(cp2)];
43 }
44
45 /**
46 * Look for the next extended grapheme cluster boundary in a CharSequence. It assumes
47 * the start of the char sequence is a boundary.
48 * <p>
49 * See Unicode Standard Annex #29 Unicode Text Segmentation for the specification
50 * for the extended grapheme cluster boundary rules. The following implementation
51 * is based on version 12.0 of the annex.
52 * (http://www.unicode.org/reports/tr29/tr29-35.html)
53 *
54 * @param src the {@code CharSequence} to be scanned
55 * @param off offset to start looking for the next boundary in the src
56 * @param limit limit offset in the src (exclusive)
57 * @return the next possible boundary
58 */
59 static int nextBoundary(CharSequence src, int off, int limit) {
60 Objects.checkFromToIndex(off, limit, src.length());
61
62 int ch0 = Character.codePointAt(src, 0);
63 int ret = Character.charCount(ch0);
64 int ch1;
65 // indicates whether gb11 or gb12 is underway
66 int t0 = getGraphemeType(ch0);
67 int riCount = t0 == RI ? 1 : 0;
68 boolean gb11 = t0 == EXTENDED_PICTOGRAPHIC;
69 while (ret < limit) {
70 ch1 = Character.codePointAt(src, ret);
71 int t1 = getGraphemeType(ch1);
72
73 if (gb11 && t0 == ZWJ && t1 == EXTENDED_PICTOGRAPHIC) {
74 gb11 = false;
75 } else if (riCount % 2 == 1 && t0 == RI && t1 == RI) {
76 // continue for gb12
77 } else if (rules[t0][t1]) {
78 if (ret > off) {
79 break;
80 } else {
81 gb11 = t1 == EXTENDED_PICTOGRAPHIC;
82 riCount = 0;
83 }
84 }
85
86 riCount += (t1 == RI) ? 1 : 0;
87 t0 = t1;
88
89 ret += Character.charCount(ch1);
90 }
91 return ret;
92 }
93
94 // types
95 private static final int OTHER = 0;
96 private static final int CR = 1;
97 private static final int LF = 2;
98 private static final int CONTROL = 3;
99 private static final int EXTEND = 4;
100 private static final int ZWJ = 5;
101 private static final int RI = 6;
102 private static final int PREPEND = 7;
103 private static final int SPACINGMARK = 8;
104 private static final int L = 9;
105 private static final int V = 10;
106 private static final int T = 11;
107 private static final int LV = 12;
108 private static final int LVT = 13;
109 private static final int EXTENDED_PICTOGRAPHIC = 14;
110
111 private static final int FIRST_TYPE = 0;
112 private static final int LAST_TYPE = 14;
113
114 private static boolean[][] rules;
115 static {
116 rules = new boolean[LAST_TYPE + 1][LAST_TYPE + 1];
117 // GB 999 Any + Any -> default
118 for (int i = FIRST_TYPE; i <= LAST_TYPE; i++)
119 for (int j = FIRST_TYPE; j <= LAST_TYPE; j++)
120 rules[i][j] = true;
121 // GB 6 L x (L | V | LV | VT)
122 rules[L][L] = false;
123 rules[L][V] = false;
124 rules[L][LV] = false;
125 rules[L][LVT] = false;
126 // GB 7 (LV | V) x (V | T)
127 rules[LV][V] = false;
128 rules[LV][T] = false;
129 rules[V][V] = false;
130 rules[V][T] = false;
131 // GB 8 (LVT | T) x T
132 rules[LVT][T] = false;
133 rules[T][T] = false;
134 // GB 9 x (Extend|ZWJ)
135 // GB 9a x Spacing Mark
136 // GB 9b Prepend x
137 for (int i = FIRST_TYPE; i <= LAST_TYPE; i++) {
138 rules[i][EXTEND] = false;
139 rules[i][ZWJ] = false;
140 rules[i][SPACINGMARK] = false;
141 rules[PREPEND][i] = false;
142 }
143 // GB 4 (Control | CR | LF) +
144 // GB 5 + (Control | CR | LF)
145 for (int i = FIRST_TYPE; i <= LAST_TYPE; i++)
146 for (int j = CR; j <= CONTROL; j++) {
147 rules[i][j] = true;
148 rules[j][i] = true;
149 }
150 // GB 3 CR x LF
151 rules[CR][LF] = false;
152 // GB 11 Exended_Pictographic x (Extend|ZWJ)
153 rules[EXTENDED_PICTOGRAPHIC][EXTEND] = false;
154 rules[EXTENDED_PICTOGRAPHIC][ZWJ] = false;
155 }
156
157 // Hangul syllables
158 private static final int SYLLABLE_BASE = 0xAC00;
159 private static final int LCOUNT = 19;
160 private static final int VCOUNT = 21;
161 private static final int TCOUNT = 28;
162 private static final int NCOUNT = VCOUNT * TCOUNT; // 588
163 private static final int SCOUNT = LCOUNT * NCOUNT; // 11172
164
165 // #tr29: SpacingMark exceptions: The following (which have
166 // General_Category = Spacing_Mark and would otherwise be included)
167 // are specifically excluded
168 private static boolean isExcludedSpacingMark(int cp) {
169 return cp == 0x102B || cp == 0x102C || cp == 0x1038 ||
170 cp >= 0x1062 && cp <= 0x1064 ||
171 cp >= 0x1062 && cp <= 0x106D ||
172 cp == 0x1083 ||
173 cp >= 0x1087 && cp <= 0x108C ||
174 cp == 0x108F ||
175 cp >= 0x109A && cp <= 0x109C ||
176 cp == 0x1A61 || cp == 0x1A63 || cp == 0x1A64 ||
177 cp == 0xAA7B || cp == 0xAA7D;
178 }
179
180 private static int getGraphemeType(int cp) {
181 if (cp < 0x007F) { // ASCII
182 if (cp < 32) { // Control characters
183 if (cp == 0x000D)
184 return CR;
185 if (cp == 0x000A)
186 return LF;
187 return CONTROL;
188 }
189 return OTHER;
190 }
191 return getType(cp);
192 }
193
194 @SuppressWarnings("fallthrough")
195 private static int getType(int cp) {
196 if (EmojiData.isExtendedPictographic(cp)) {
197 return EXTENDED_PICTOGRAPHIC;
198 }
199
200 int type = Character.getType(cp);
201 switch(type) {
202 case Character.UNASSIGNED:
203 // NOTE: #tr29 lists "Unassigned and Default_Ignorable_Code_Point" as Control
204 // but GraphemeBreakTest.txt lists u+0378/reserved-0378 as "Other"
205 // so type it as "Other" to make the test happy
206 if (cp == 0x0378)
207 return OTHER;
208
209 case Character.CONTROL:
210 case Character.LINE_SEPARATOR:
211 case Character.PARAGRAPH_SEPARATOR:
212 case Character.SURROGATE:
213 return CONTROL;
214 case Character.FORMAT:
215 if (cp == 0x200C ||
216 cp >= 0xE0020 && cp <= 0xE007F)
217 return EXTEND;
218 if (cp == 0x200D)
219 return ZWJ;
220 if (cp >= 0x0600 && cp <= 0x0605 ||
221 cp == 0x06DD || cp == 0x070F || cp == 0x08E2 ||
222 cp == 0x110BD || cp == 0x110CD)
223 return PREPEND;
224 return CONTROL;
225 case Character.NON_SPACING_MARK:
226 case Character.ENCLOSING_MARK:
227 // NOTE:
228 // #tr29 "plus a few General_Category = Spacing_Mark needed for
229 // canonical equivalence."
230 // but for "extended grapheme clusters" support, there is no
231 // need actually to diff "extend" and "spackmark" given GB9, GB9a
232 return EXTEND;
233 case Character.COMBINING_SPACING_MARK:
234 if (isExcludedSpacingMark(cp))
235 return OTHER;
236 // NOTE:
237 // 0x11720 and 0x11721 are mentioned in #tr29 as
238 // OTHER_LETTER but it appears their category has been updated to
239 // COMBING_SPACING_MARK already (verified in ver.8)
240 return SPACINGMARK;
241 case Character.OTHER_SYMBOL:
242 if (cp >= 0x1F1E6 && cp <= 0x1F1FF)
243 return RI;
244 return OTHER;
245 case Character.MODIFIER_LETTER:
246 case Character.MODIFIER_SYMBOL:
247 // WARNING:
248 // not mentioned in #tr29 but listed in GraphemeBreakProperty.txt
249 if (cp == 0xFF9E || cp == 0xFF9F ||
250 cp >= 0x1F3FB && cp <= 0x1F3FF)
251 return EXTEND;
252 return OTHER;
253 case Character.OTHER_LETTER:
254 if (cp == 0x0E33 || cp == 0x0EB3)
255 return SPACINGMARK;
256 // hangul jamo
257 if (cp >= 0x1100 && cp <= 0x11FF) {
258 if (cp <= 0x115F)
259 return L;
260 if (cp <= 0x11A7)
261 return V;
262 return T;
263 }
264 // hangul syllables
265 int sindex = cp - SYLLABLE_BASE;
266 if (sindex >= 0 && sindex < SCOUNT) {
267
268 if (sindex % TCOUNT == 0)
269 return LV;
270 return LVT;
271 }
272 // hangul jamo_extended A
273 if (cp >= 0xA960 && cp <= 0xA97C)
274 return L;
275 // hangul jamo_extended B
276 if (cp >= 0xD7B0 && cp <= 0xD7C6)
277 return V;
278 if (cp >= 0xD7CB && cp <= 0xD7FB)
279 return T;
280
281 // Prepend
282 switch (cp) {
283 case 0x0D4E:
284 case 0x111C2:
285 case 0x111C3:
286 case 0x11A3A:
287 case 0x11A84:
288 case 0x11A85:
289 case 0x11A86:
290 case 0x11A87:
291 case 0x11A88:
292 case 0x11A89:
293 case 0x11D46:
294 return PREPEND;
295 }
296 }
297 return OTHER;
298 }
299 }