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| 1 | /* | ||
| 2 | * Copyright (c) 2005, 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 | /* | ||
| 27 | ******************************************************************************* | ||
| 28 | * (C) Copyright IBM Corp. 1996-2005 - All Rights Reserved * | ||
| 29 | * * | ||
| 30 | * The original version of this source code and documentation is copyrighted * | ||
| 31 | * and owned by IBM, These materials are provided under terms of a License * | ||
| 32 | * Agreement between IBM and Sun. This technology is protected by multiple * | ||
| 33 | * US and International patents. This notice and attribution to IBM may not * | ||
| 34 | * to removed. * | ||
| 35 | ******************************************************************************* | ||
| 36 | */ | ||
| 37 | |||
| 38 | /* | ||
| 39 | ********************************************************************** | ||
| 40 | * Author: Alan Liu | ||
| 41 | * Created: September 23 2003 | ||
| 42 | * Since: ICU 2.8 | ||
| 43 | ********************************************************************** | ||
| 44 | */ | ||
| 45 | |||
| 46 | package sun.text.normalizer; | ||
| 47 | |||
| 48 | import java.text.ParsePosition; | ||
| 49 | |||
| 50 | /** | ||
| 51 | * An iterator that returns 32-bit code points. This class is deliberately | ||
| 52 | * <em>not</em> related to any of the JDK or ICU4J character iterator classes | ||
| 53 | * in order to minimize complexity. | ||
| 54 | * @author Alan Liu | ||
| 55 | * @since ICU 2.8 | ||
| 56 | */ | ||
| 57 | public class RuleCharacterIterator { | ||
| 58 | |||
| 59 | // TODO: Ideas for later. (Do not implement if not needed, lest the | ||
| 60 | // code coverage numbers go down due to unused methods.) | ||
| 61 | // 1. Add a copy constructor, equals() method, clone() method. | ||
| 62 | // 2. Rather than return DONE, throw an exception if the end | ||
| 63 | // is reached -- this is an alternate usage model, probably not useful. | ||
| 64 | // 3. Return isEscaped from next(). If this happens, | ||
| 65 | // don't keep an isEscaped member variable. | ||
| 66 | |||
| 67 | /** | ||
| 68 | * Text being iterated. | ||
| 69 | */ | ||
| 70 | private String text; | ||
| 71 | |||
| 72 | /** | ||
| 73 | * Position of iterator. | ||
| 74 | */ | ||
| 75 | private ParsePosition pos; | ||
| 76 | |||
| 77 | /** | ||
| 78 | * Symbol table used to parse and dereference variables. May be null. | ||
| 79 | */ | ||
| 80 | private SymbolTable sym; | ||
| 81 | |||
| 82 | /** | ||
| 83 | * Current variable expansion, or null if none. | ||
| 84 | */ | ||
| 85 | private char[] buf; | ||
| 86 | |||
| 87 | /** | ||
| 88 | * Position within buf[]. Meaningless if buf == null. | ||
| 89 | */ | ||
| 90 | private int bufPos; | ||
| 91 | |||
| 92 | /** | ||
| 93 | * Flag indicating whether the last character was parsed from an escape. | ||
| 94 | */ | ||
| 95 | private boolean isEscaped; | ||
| 96 | |||
| 97 | /** | ||
| 98 | * Value returned when there are no more characters to iterate. | ||
| 99 | */ | ||
| 100 | public static final int DONE = -1; | ||
| 101 | |||
| 102 | /** | ||
| 103 | * Bitmask option to enable parsing of variable names. If (options & | ||
| 104 | * PARSE_VARIABLES) != 0, then an embedded variable will be expanded to | ||
| 105 | * its value. Variables are parsed using the SymbolTable API. | ||
| 106 | */ | ||
| 107 | public static final int PARSE_VARIABLES = 1; | ||
| 108 | |||
| 109 | /** | ||
| 110 | * Bitmask option to enable parsing of escape sequences. If (options & | ||
| 111 | * PARSE_ESCAPES) != 0, then an embedded escape sequence will be expanded | ||
| 112 | * to its value. Escapes are parsed using Utility.unescapeAt(). | ||
| 113 | */ | ||
| 114 | public static final int PARSE_ESCAPES = 2; | ||
| 115 | |||
| 116 | /** | ||
| 117 | * Bitmask option to enable skipping of whitespace. If (options & | ||
| 118 | * SKIP_WHITESPACE) != 0, then whitespace characters will be silently | ||
| 119 | * skipped, as if they were not present in the input. Whitespace | ||
| 120 | * characters are defined by UCharacterProperty.isRuleWhiteSpace(). | ||
| 121 | */ | ||
| 122 | public static final int SKIP_WHITESPACE = 4; | ||
| 123 | |||
| 124 | /** | ||
| 125 | * Constructs an iterator over the given text, starting at the given | ||
| 126 | * position. | ||
| 127 | * @param text the text to be iterated | ||
| 128 | * @param sym the symbol table, or null if there is none. If sym is null, | ||
| 129 | * then variables will not be deferenced, even if the PARSE_VARIABLES | ||
| 130 | * option is set. | ||
| 131 | * @param pos upon input, the index of the next character to return. If a | ||
| 132 | * variable has been dereferenced, then pos will <em>not</em> increment as | ||
| 133 | * characters of the variable value are iterated. | ||
| 134 | */ | ||
| 135 | public RuleCharacterIterator(String text, SymbolTable sym, | ||
| 136 | ParsePosition pos) { | ||
| 137 | if (text == null || pos.getIndex() > text.length()) { | ||
| 138 | throw new IllegalArgumentException(); | ||
| 139 | } | ||
| 140 | this.text = text; | ||
| 141 | this.sym = sym; | ||
| 142 | this.pos = pos; | ||
| 143 | buf = null; | ||
| 144 | } | ||
| 145 | |||
| 146 | /** | ||
| 147 | * Returns true if this iterator has no more characters to return. | ||
| 148 | */ | ||
| 149 | public boolean atEnd() { | ||
| 150 | return buf == null && pos.getIndex() == text.length(); | ||
| 151 | } | ||
| 152 | |||
| 153 | /** | ||
| 154 | * Returns the next character using the given options, or DONE if there | ||
| 155 | * are no more characters, and advance the position to the next | ||
| 156 | * character. | ||
| 157 | * @param options one or more of the following options, bitwise-OR-ed | ||
| 158 | * together: PARSE_VARIABLES, PARSE_ESCAPES, SKIP_WHITESPACE. | ||
| 159 | * @return the current 32-bit code point, or DONE | ||
| 160 | */ | ||
| 161 | public int next(int options) { | ||
| 162 | int c = DONE; | ||
| 163 | isEscaped = false; | ||
| 164 | |||
| 165 | for (;;) { | ||
| 166 | c = _current(); | ||
| 167 | _advance(UTF16.getCharCount(c)); | ||
| 168 | |||
| 169 | if (c == SymbolTable.SYMBOL_REF && buf == null && | ||
| 170 | (options & PARSE_VARIABLES) != 0 && sym != null) { | ||
| 171 | String name = sym.parseReference(text, pos, text.length()); | ||
| 172 | // If name == null there was an isolated SYMBOL_REF; | ||
| 173 | // return it. Caller must be prepared for this. | ||
| 174 | if (name == null) { | ||
| 175 | break; | ||
| 176 | } | ||
| 177 | bufPos = 0; | ||
| 178 | buf = sym.lookup(name); | ||
| 179 | if (buf == null) { | ||
| 180 | throw new IllegalArgumentException( | ||
| 181 | "Undefined variable: " + name); | ||
| 182 | } | ||
| 183 | // Handle empty variable value | ||
| 184 | if (buf.length == 0) { | ||
| 185 | buf = null; | ||
| 186 | } | ||
| 187 | continue; | ||
| 188 | } | ||
| 189 | |||
| 190 | if ((options & SKIP_WHITESPACE) != 0 && | ||
| 191 | UCharacterProperty.isRuleWhiteSpace(c)) { | ||
| 192 | continue; | ||
| 193 | } | ||
| 194 | |||
| 195 | if (c == '\\' && (options & PARSE_ESCAPES) != 0) { | ||
| 196 | int offset[] = new int[] { 0 }; | ||
| 197 | c = Utility.unescapeAt(lookahead(), offset); | ||
| 198 | jumpahead(offset[0]); | ||
| 199 | isEscaped = true; | ||
| 200 | if (c < 0) { | ||
| 201 | throw new IllegalArgumentException("Invalid escape"); | ||
| 202 | } | ||
| 203 | } | ||
| 204 | |||
| 205 | break; | ||
| 206 | } | ||
| 207 | |||
| 208 | return c; | ||
| 209 | } | ||
| 210 | |||
| 211 | /** | ||
| 212 | * Returns true if the last character returned by next() was | ||
| 213 | * escaped. This will only be the case if the option passed in to | ||
| 214 | * next() included PARSE_ESCAPED and the next character was an | ||
| 215 | * escape sequence. | ||
| 216 | */ | ||
| 217 | public boolean isEscaped() { | ||
| 218 | return isEscaped; | ||
| 219 | } | ||
| 220 | |||
| 221 | /** | ||
| 222 | * Returns true if this iterator is currently within a variable expansion. | ||
| 223 | */ | ||
| 224 | public boolean inVariable() { | ||
| 225 | return buf != null; | ||
| 226 | } | ||
| 227 | |||
| 228 | /** | ||
| 229 | * Returns an object which, when later passed to setPos(), will | ||
| 230 | * restore this iterator's position. Usage idiom: | ||
| 231 | * | ||
| 232 | * RuleCharacterIterator iterator = ...; | ||
| 233 | * Object pos = iterator.getPos(null); // allocate position object | ||
| 234 | * for (;;) { | ||
| 235 | * pos = iterator.getPos(pos); // reuse position object | ||
| 236 | * int c = iterator.next(...); | ||
| 237 | * ... | ||
| 238 | * } | ||
| 239 | * iterator.setPos(pos); | ||
| 240 | * | ||
| 241 | * @param p a position object previously returned by getPos(), | ||
| 242 | * or null. If not null, it will be updated and returned. If | ||
| 243 | * null, a new position object will be allocated and returned. | ||
| 244 | * @return a position object which may be passed to setPos(), | ||
| 245 | * either `p,' or if `p' == null, a newly-allocated object | ||
| 246 | */ | ||
| 247 | public Object getPos(Object p) { | ||
| 248 | if (p == null) { | ||
| 249 | return new Object[] {buf, new int[] {pos.getIndex(), bufPos}}; | ||
| 250 | } | ||
| 251 | Object[] a = (Object[]) p; | ||
| 252 | a[0] = buf; | ||
| 253 | int[] v = (int[]) a[1]; | ||
| 254 | v[0] = pos.getIndex(); | ||
| 255 | v[1] = bufPos; | ||
| 256 | return p; | ||
| 257 | } | ||
| 258 | |||
| 259 | /** | ||
| 260 | * Restores this iterator to the position it had when getPos() | ||
| 261 | * returned the given object. | ||
| 262 | * @param p a position object previously returned by getPos() | ||
| 263 | */ | ||
| 264 | public void setPos(Object p) { | ||
| 265 | Object[] a = (Object[]) p; | ||
| 266 | buf = (char[]) a[0]; | ||
| 267 | int[] v = (int[]) a[1]; | ||
| 268 | pos.setIndex(v[0]); | ||
| 269 | bufPos = v[1]; | ||
| 270 | } | ||
| 271 | |||
| 272 | /** | ||
| 273 | * Skips ahead past any ignored characters, as indicated by the given | ||
| 274 | * options. This is useful in conjunction with the lookahead() method. | ||
| 275 | * | ||
| 276 | * Currently, this only has an effect for SKIP_WHITESPACE. | ||
| 277 | * @param options one or more of the following options, bitwise-OR-ed | ||
| 278 | * together: PARSE_VARIABLES, PARSE_ESCAPES, SKIP_WHITESPACE. | ||
| 279 | */ | ||
| 280 | public void skipIgnored(int options) { | ||
| 281 | if ((options & SKIP_WHITESPACE) != 0) { | ||
| 282 | for (;;) { | ||
| 283 | int a = _current(); | ||
| 284 | if (!UCharacterProperty.isRuleWhiteSpace(a)) break; | ||
| 285 | _advance(UTF16.getCharCount(a)); | ||
| 286 | } | ||
| 287 | } | ||
| 288 | } | ||
| 289 | |||
| 290 | /** | ||
| 291 | * Returns a string containing the remainder of the characters to be | ||
| 292 | * returned by this iterator, without any option processing. If the | ||
| 293 | * iterator is currently within a variable expansion, this will only | ||
| 294 | * extend to the end of the variable expansion. This method is provided | ||
| 295 | * so that iterators may interoperate with string-based APIs. The typical | ||
| 296 | * sequence of calls is to call skipIgnored(), then call lookahead(), then | ||
| 297 | * parse the string returned by lookahead(), then call jumpahead() to | ||
| 298 | * resynchronize the iterator. | ||
| 299 | * @return a string containing the characters to be returned by future | ||
| 300 | * calls to next() | ||
| 301 | */ | ||
| 302 | public String lookahead() { | ||
| 303 | if (buf != null) { | ||
| 304 | return new String(buf, bufPos, buf.length - bufPos); | ||
| 305 | } else { | ||
| 306 | return text.substring(pos.getIndex()); | ||
| 307 | } | ||
| 308 | } | ||
| 309 | |||
| 310 | /** | ||
| 311 | * Advances the position by the given number of 16-bit code units. | ||
| 312 | * This is useful in conjunction with the lookahead() method. | ||
| 313 | * @param count the number of 16-bit code units to jump over | ||
| 314 | */ | ||
| 315 | public void jumpahead(int count) { | ||
| 316 | if (count < 0) { | ||
| 317 | throw new IllegalArgumentException(); | ||
| 318 | } | ||
| 319 | if (buf != null) { | ||
| 320 | bufPos += count; | ||
| 321 | if (bufPos > buf.length) { | ||
| 322 | throw new IllegalArgumentException(); | ||
| 323 | } | ||
| 324 | if (bufPos == buf.length) { | ||
| 325 | buf = null; | ||
| 326 | } | ||
| 327 | } else { | ||
| 328 | int i = pos.getIndex() + count; | ||
| 329 | pos.setIndex(i); | ||
| 330 | if (i > text.length()) { | ||
| 331 | throw new IllegalArgumentException(); | ||
| 332 | } | ||
| 333 | } | ||
| 334 | } | ||
| 335 | |||
| 336 | /** | ||
| 337 | * Returns the current 32-bit code point without parsing escapes, parsing | ||
| 338 | * variables, or skipping whitespace. | ||
| 339 | * @return the current 32-bit code point | ||
| 340 | */ | ||
| 341 | private int _current() { | ||
| 342 | if (buf != null) { | ||
| 343 | return UTF16.charAt(buf, 0, buf.length, bufPos); | ||
| 344 | } else { | ||
| 345 | int i = pos.getIndex(); | ||
| 346 | return (i < text.length()) ? UTF16.charAt(text, i) : DONE; | ||
| 347 | } | ||
| 348 | } | ||
| 349 | |||
| 350 | /** | ||
| 351 | * Advances the position by the given amount. | ||
| 352 | * @param count the number of 16-bit code units to advance past | ||
| 353 | */ | ||
| 354 | private void _advance(int count) { | ||
| 355 | if (buf != null) { | ||
| 356 | bufPos += count; | ||
| 357 | if (bufPos == buf.length) { | ||
| 358 | buf = null; | ||
| 359 | } | ||
| 360 | } else { | ||
| 361 | pos.setIndex(pos.getIndex() + count); | ||
| 362 | if (pos.getIndex() > text.length()) { | ||
| 363 | pos.setIndex(text.length()); | ||
| 364 | } | ||
| 365 | } | ||
| 366 | } | ||
| 367 | } | ||