1 /*
2 * Copyright (c) 2005, 2020, 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 * Copyright (C) 1996-2014, International Business Machines Corporation and
29 * others. All Rights Reserved.
30 ******************************************************************************
31 */
32
33 package jdk.internal.icu.impl;
34
35 import jdk.internal.icu.text.UTF16;
36
37 import java.io.DataInputStream;
38 import java.io.InputStream;
39 import java.io.IOException;
40
41 /**
42 * Trie implementation which stores data in char, 16 bits.
43 * @author synwee
44 * @see com.ibm.icu.impl.Trie
45 * @since release 2.1, Jan 01 2002
46 */
47
48 // note that i need to handle the block calculations later, since chartrie
49 // in icu4c uses the same index array.
50 public class CharTrie extends Trie
51 {
52 // public constructors ---------------------------------------------
53
54 /**
55 * <p>Creates a new Trie with the settings for the trie data.</p>
56 * <p>Unserialize the 32-bit-aligned input stream and use the data for the
57 * trie.</p>
58 * @param inputStream file input stream to a ICU data file, containing
59 * the trie
60 * @param dataManipulate object which provides methods to parse the char
61 * data
62 * @throws IOException thrown when data reading fails
63 * @draft 2.1
64 */
65 public CharTrie(InputStream inputStream,
66 DataManipulate dataManipulate) throws IOException
67 {
68 super(inputStream, dataManipulate);
69
70 if (!isCharTrie()) {
71 throw new IllegalArgumentException(
72 "Data given does not belong to a char trie.");
73 }
74 }
75
76 // public methods --------------------------------------------------
77
78 /**
79 * Gets the value associated with the codepoint.
80 * If no value is associated with the codepoint, a default value will be
81 * returned.
82 * @param ch codepoint
83 * @return offset to data
84 */
85 public final char getCodePointValue(int ch)
86 {
87 int offset;
88
89 // fastpath for U+0000..U+D7FF
90 if(0 <= ch && ch < UTF16.LEAD_SURROGATE_MIN_VALUE) {
91 // copy of getRawOffset()
92 offset = (m_index_[ch >> INDEX_STAGE_1_SHIFT_] << INDEX_STAGE_2_SHIFT_)
93 + (ch & INDEX_STAGE_3_MASK_);
94 return m_data_[offset];
95 }
96
97 // handle U+D800..U+10FFFF
98 offset = getCodePointOffset(ch);
99
100 // return -1 if there is an error, in this case we return the default
101 // value: m_initialValue_
102 return (offset >= 0) ? m_data_[offset] : m_initialValue_;
103 }
104
105 /**
106 * Gets the value to the data which this lead surrogate character points
107 * to.
108 * Returned data may contain folding offset information for the next
109 * trailing surrogate character.
110 * This method does not guarantee correct results for trail surrogates.
111 * @param ch lead surrogate character
112 * @return data value
113 */
114 public final char getLeadValue(char ch)
115 {
116 return m_data_[getLeadOffset(ch)];
117 }
118
119 // protected methods -----------------------------------------------
120
121 /**
122 * <p>Parses the input stream and stores its trie content into a index and
123 * data array</p>
124 * @param inputStream data input stream containing trie data
125 * @exception IOException thrown when data reading fails
126 */
127 protected final void unserialize(InputStream inputStream)
128 throws IOException
129 {
130 DataInputStream input = new DataInputStream(inputStream);
131 int indexDataLength = m_dataOffset_ + m_dataLength_;
132 m_index_ = new char[indexDataLength];
133 for (int i = 0; i < indexDataLength; i ++) {
134 m_index_[i] = input.readChar();
135 }
136 m_data_ = m_index_;
137 m_initialValue_ = m_data_[m_dataOffset_];
138 }
139
140 /**
141 * Gets the offset to the data which the surrogate pair points to.
142 * @param lead lead surrogate
143 * @param trail trailing surrogate
144 * @return offset to data
145 * @draft 2.1
146 */
147 protected final int getSurrogateOffset(char lead, char trail)
148 {
149 if (m_dataManipulate_ == null) {
150 throw new NullPointerException(
151 "The field DataManipulate in this Trie is null");
152 }
153
154 // get fold position for the next trail surrogate
155 int offset = m_dataManipulate_.getFoldingOffset(getLeadValue(lead));
156
157 // get the real data from the folded lead/trail units
158 if (offset > 0) {
159 return getRawOffset(offset, (char)(trail & SURROGATE_MASK_));
160 }
161
162 // return -1 if there is an error, in this case we return the default
163 // value: m_initialValue_
164 return -1;
165 }
166
167 // private data members --------------------------------------------
168
169 /**
170 * Default value
171 */
172 private char m_initialValue_;
173 /**
174 * Array of char data
175 */
176 private char m_data_[];
177 }