1 /*
2 * Copyright (c) 2005, 2009, 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 * (C) Copyright IBM Corp. and others, 1996-2009 - All Rights Reserved *
28 * *
29 * The original version of this source code and documentation is copyrighted *
30 * and owned by IBM, These materials are provided under terms of a License *
31 * Agreement between IBM and Sun. This technology is protected by multiple *
32 * US and International patents. This notice and attribution to IBM may not *
33 * to removed. *
34 *******************************************************************************
35 */
36
37 package sun.text.normalizer;
38
39 import java.io.DataInputStream;
40 import java.io.InputStream;
41 import java.io.IOException;
42
43 /**
44 * <p>A trie is a kind of compressed, serializable table of values
45 * associated with Unicode code points (0..0x10ffff).</p>
46 * <p>This class defines the basic structure of a trie and provides methods
47 * to <b>retrieve the offsets to the actual data</b>.</p>
48 * <p>Data will be the form of an array of basic types, char or int.</p>
49 * <p>The actual data format will have to be specified by the user in the
50 * inner static interface com.ibm.icu.impl.Trie.DataManipulate.</p>
51 * <p>This trie implementation is optimized for getting offset while walking
52 * forward through a UTF-16 string.
53 * Therefore, the simplest and fastest access macros are the
54 * fromLead() and fromOffsetTrail() methods.
55 * The fromBMP() method are a little more complicated; they get offsets even
56 * for lead surrogate codepoints, while the fromLead() method get special
57 * "folded" offsets for lead surrogate code units if there is relevant data
58 * associated with them.
59 * From such a folded offsets, an offset needs to be extracted to supply
60 * to the fromOffsetTrail() methods.
61 * To handle such supplementary codepoints, some offset information are kept
62 * in the data.</p>
63 * <p>Methods in com.ibm.icu.impl.Trie.DataManipulate are called to retrieve
64 * that offset from the folded value for the lead surrogate unit.</p>
65 * <p>For examples of use, see com.ibm.icu.impl.CharTrie or
66 * com.ibm.icu.impl.IntTrie.</p>
67 * @author synwee
68 * @see com.ibm.icu.impl.CharTrie
69 * @see com.ibm.icu.impl.IntTrie
70 * @since release 2.1, Jan 01 2002
71 */
72 public abstract class Trie
73 {
74 // public class declaration ----------------------------------------
75
76 /**
77 * Character data in com.ibm.impl.Trie have different user-specified format
78 * for different purposes.
79 * This interface specifies methods to be implemented in order for
80 * com.ibm.impl.Trie, to surrogate offset information encapsulated within
81 * the data.
82 */
83 public static interface DataManipulate
84 {
85 /**
86 * Called by com.ibm.icu.impl.Trie to extract from a lead surrogate's
87 * data
88 * the index array offset of the indexes for that lead surrogate.
89 * @param value data value for a surrogate from the trie, including the
90 * folding offset
91 * @return data offset or 0 if there is no data for the lead surrogate
92 */
93 public int getFoldingOffset(int value);
94 }
95
96 // default implementation
97 private static class DefaultGetFoldingOffset implements DataManipulate {
98 public int getFoldingOffset(int value) {
99 return value;
100 }
101 }
102
103 // protected constructor -------------------------------------------
104
105 /**
106 * Trie constructor for CharTrie use.
107 * @param inputStream ICU data file input stream which contains the
108 * trie
109 * @param dataManipulate object containing the information to parse the
110 * trie data
111 * @throws IOException thrown when input stream does not have the
112 * right header.
113 */
114 protected Trie(InputStream inputStream,
115 DataManipulate dataManipulate) throws IOException
116 {
117 DataInputStream input = new DataInputStream(inputStream);
118 // Magic number to authenticate the data.
119 int signature = input.readInt();
120 m_options_ = input.readInt();
121
122 if (!checkHeader(signature)) {
123 throw new IllegalArgumentException("ICU data file error: Trie header authentication failed, please check if you have the most updated ICU data file");
124 }
125
126 if(dataManipulate != null) {
127 m_dataManipulate_ = dataManipulate;
128 } else {
129 m_dataManipulate_ = new DefaultGetFoldingOffset();
130 }
131 m_isLatin1Linear_ = (m_options_ &
132 HEADER_OPTIONS_LATIN1_IS_LINEAR_MASK_) != 0;
133 m_dataOffset_ = input.readInt();
134 m_dataLength_ = input.readInt();
135 unserialize(inputStream);
136 }
137
138 /**
139 * Trie constructor
140 * @param index array to be used for index
141 * @param options used by the trie
142 * @param dataManipulate object containing the information to parse the
143 * trie data
144 */
145 protected Trie(char index[], int options, DataManipulate dataManipulate)
146 {
147 m_options_ = options;
148 if(dataManipulate != null) {
149 m_dataManipulate_ = dataManipulate;
150 } else {
151 m_dataManipulate_ = new DefaultGetFoldingOffset();
152 }
153 m_isLatin1Linear_ = (m_options_ &
154 HEADER_OPTIONS_LATIN1_IS_LINEAR_MASK_) != 0;
155 m_index_ = index;
156 m_dataOffset_ = m_index_.length;
157 }
158
159 // protected data members ------------------------------------------
160
161 /**
162 * Lead surrogate code points' index displacement in the index array.
163 * <pre>{@code
164 * 0x10000-0xd800=0x2800
165 * 0x2800 >> INDEX_STAGE_1_SHIFT_
166 * }</pre>
167 */
168 protected static final int LEAD_INDEX_OFFSET_ = 0x2800 >> 5;
169 /**
170 * Shift size for shifting right the input index. 1..9
171 */
172 protected static final int INDEX_STAGE_1_SHIFT_ = 5;
173 /**
174 * Shift size for shifting left the index array values.
175 * Increases possible data size with 16-bit index values at the cost
176 * of compactability.
177 * This requires blocks of stage 2 data to be aligned by
178 * DATA_GRANULARITY.
179 * 0..INDEX_STAGE_1_SHIFT
180 */
181 protected static final int INDEX_STAGE_2_SHIFT_ = 2;
182 /**
183 * Number of data values in a stage 2 (data array) block.
184 */
185 protected static final int DATA_BLOCK_LENGTH=1<<INDEX_STAGE_1_SHIFT_;
186 /**
187 * Mask for getting the lower bits from the input index.
188 * DATA_BLOCK_LENGTH - 1.
189 */
190 protected static final int INDEX_STAGE_3_MASK_ = DATA_BLOCK_LENGTH - 1;
191 /** Number of bits of a trail surrogate that are used in index table lookups. */
192 protected static final int SURROGATE_BLOCK_BITS=10-INDEX_STAGE_1_SHIFT_;
193 /**
194 * Number of index (stage 1) entries per lead surrogate.
195 * Same as number of index entries for 1024 trail surrogates,
196 * {@code ==0x400>>INDEX_STAGE_1_SHIFT_}
197 */
198 protected static final int SURROGATE_BLOCK_COUNT=(1<<SURROGATE_BLOCK_BITS);
199 /** Length of the BMP portion of the index (stage 1) array. */
200 protected static final int BMP_INDEX_LENGTH=0x10000>>INDEX_STAGE_1_SHIFT_;
201 /**
202 * Surrogate mask to use when shifting offset to retrieve supplementary
203 * values
204 */
205 protected static final int SURROGATE_MASK_ = 0x3FF;
206 /**
207 * Index or UTF16 characters
208 */
209 protected char m_index_[];
210 /**
211 * Internal TrieValue which handles the parsing of the data value.
212 * This class is to be implemented by the user
213 */
214 protected DataManipulate m_dataManipulate_;
215 /**
216 * Start index of the data portion of the trie. CharTrie combines
217 * index and data into a char array, so this is used to indicate the
218 * initial offset to the data portion.
219 * Note this index always points to the initial value.
220 */
221 protected int m_dataOffset_;
222 /**
223 * Length of the data array
224 */
225 protected int m_dataLength_;
226
227 // protected methods -----------------------------------------------
228
229 /**
230 * Gets the offset to the data which the surrogate pair points to.
231 * @param lead lead surrogate
232 * @param trail trailing surrogate
233 * @return offset to data
234 */
235 protected abstract int getSurrogateOffset(char lead, char trail);
236
237 /**
238 * Gets the value at the argument index
239 * @param index value at index will be retrieved
240 * @return 32 bit value
241 */
242 protected abstract int getValue(int index);
243
244 /**
245 * Gets the default initial value
246 * @return 32 bit value
247 */
248 protected abstract int getInitialValue();
249
250 /**
251 * Gets the offset to the data which the index ch after variable offset
252 * points to.
253 * Note for locating a non-supplementary character data offset, calling
254 * <p>
255 * getRawOffset(0, ch);
256 * </p>
257 * will do. Otherwise if it is a supplementary character formed by
258 * surrogates lead and trail. Then we would have to call getRawOffset()
259 * with getFoldingIndexOffset(). See getSurrogateOffset().
260 * @param offset index offset which ch is to start from
261 * @param ch index to be used after offset
262 * @return offset to the data
263 */
264 protected final int getRawOffset(int offset, char ch)
265 {
266 return (m_index_[offset + (ch >> INDEX_STAGE_1_SHIFT_)]
267 << INDEX_STAGE_2_SHIFT_)
268 + (ch & INDEX_STAGE_3_MASK_);
269 }
270
271 /**
272 * Gets the offset to data which the BMP character points to
273 * Treats a lead surrogate as a normal code point.
274 * @param ch BMP character
275 * @return offset to data
276 */
277 protected final int getBMPOffset(char ch)
278 {
279 return (ch >= UTF16.LEAD_SURROGATE_MIN_VALUE
280 && ch <= UTF16.LEAD_SURROGATE_MAX_VALUE)
281 ? getRawOffset(LEAD_INDEX_OFFSET_, ch)
282 : getRawOffset(0, ch);
283 // using a getRawOffset(ch) makes no diff
284 }
285
286 /**
287 * Gets the offset to the data which this lead surrogate character points
288 * to.
289 * Data at the returned offset may contain folding offset information for
290 * the next trailing surrogate character.
291 * @param ch lead surrogate character
292 * @return offset to data
293 */
294 protected final int getLeadOffset(char ch)
295 {
296 return getRawOffset(0, ch);
297 }
298
299 /**
300 * Internal trie getter from a code point.
301 * Could be faster(?) but longer with
302 * {@code if((c32)<=0xd7ff) { (result)=_TRIE_GET_RAW(trie, data, 0, c32); }}
303 * Gets the offset to data which the codepoint points to
304 * @param ch codepoint
305 * @return offset to data
306 */
307 protected final int getCodePointOffset(int ch)
308 {
309 // if ((ch >> 16) == 0) slower
310 if (ch < 0) {
311 return -1;
312 } else if (ch < UTF16.LEAD_SURROGATE_MIN_VALUE) {
313 // fastpath for the part of the BMP below surrogates (D800) where getRawOffset() works
314 return getRawOffset(0, (char)ch);
315 } else if (ch < UTF16.SUPPLEMENTARY_MIN_VALUE) {
316 // BMP codepoint
317 return getBMPOffset((char)ch);
318 } else if (ch <= UCharacter.MAX_VALUE) {
319 // look at the construction of supplementary characters
320 // trail forms the ends of it.
321 return getSurrogateOffset(UTF16.getLeadSurrogate(ch),
322 (char)(ch & SURROGATE_MASK_));
323 } else {
324 // return -1 // if there is an error, in this case we return
325 return -1;
326 }
327 }
328
329 /**
330 * <p>Parses the inputstream and creates the trie index with it.</p>
331 * <p>This is overwritten by the child classes.
332 * @param inputStream input stream containing the trie information
333 * @exception IOException thrown when data reading fails.
334 */
335 protected void unserialize(InputStream inputStream) throws IOException
336 {
337 //indexLength is a multiple of 1024 >> INDEX_STAGE_2_SHIFT_
338 m_index_ = new char[m_dataOffset_];
339 DataInputStream input = new DataInputStream(inputStream);
340 for (int i = 0; i < m_dataOffset_; i ++) {
341 m_index_[i] = input.readChar();
342 }
343 }
344
345 /**
346 * Determines if this is a 32 bit trie
347 * @return true if options specifies this is a 32 bit trie
348 */
349 protected final boolean isIntTrie()
350 {
351 return (m_options_ & HEADER_OPTIONS_DATA_IS_32_BIT_) != 0;
352 }
353
354 /**
355 * Determines if this is a 16 bit trie
356 * @return true if this is a 16 bit trie
357 */
358 protected final boolean isCharTrie()
359 {
360 return (m_options_ & HEADER_OPTIONS_DATA_IS_32_BIT_) == 0;
361 }
362
363 // private data members --------------------------------------------
364
365 /**
366 * Latin 1 option mask
367 */
368 protected static final int HEADER_OPTIONS_LATIN1_IS_LINEAR_MASK_ = 0x200;
369 /**
370 * Constant number to authenticate the byte block
371 */
372 protected static final int HEADER_SIGNATURE_ = 0x54726965;
373 /**
374 * Header option formatting
375 */
376 private static final int HEADER_OPTIONS_SHIFT_MASK_ = 0xF;
377 protected static final int HEADER_OPTIONS_INDEX_SHIFT_ = 4;
378 protected static final int HEADER_OPTIONS_DATA_IS_32_BIT_ = 0x100;
379
380 /**
381 * Flag indicator for Latin quick access data block
382 */
383 private boolean m_isLatin1Linear_;
384
385 /**
386 * <p>Trie options field.</p>
387 * <p>options bit field:<br>
388 * 9 1 = Latin-1 data is stored linearly at data + DATA_BLOCK_LENGTH<br>
389 * 8 0 = 16-bit data, 1=32-bit data<br>
390 * 7..4 INDEX_STAGE_1_SHIFT // 0..INDEX_STAGE_2_SHIFT<br>
391 * 3..0 INDEX_STAGE_2_SHIFT // 1..9<br>
392 */
393 private int m_options_;
394
395 // private methods ---------------------------------------------------
396
397 /**
398 * Authenticates raw data header.
399 * Checking the header information, signature and options.
400 * @param signature This contains the options and type of a Trie
401 * @return true if the header is authenticated valid
402 */
403 private final boolean checkHeader(int signature)
404 {
405 // check the signature
406 // Trie in big-endian US-ASCII (0x54726965).
407 // Magic number to authenticate the data.
408 if (signature != HEADER_SIGNATURE_) {
409 return false;
410 }
411
412 if ((m_options_ & HEADER_OPTIONS_SHIFT_MASK_) !=
413 INDEX_STAGE_1_SHIFT_ ||
414 ((m_options_ >> HEADER_OPTIONS_INDEX_SHIFT_) &
415 HEADER_OPTIONS_SHIFT_MASK_)
416 != INDEX_STAGE_2_SHIFT_) {
417 return false;
418 }
419 return true;
420 }
421 }