Source code: org/hsqldb/Like.java
1 /* Copyrights and Licenses
2 *
3 * This product includes Hypersonic SQL.
4 * Originally developed by Thomas Mueller and the Hypersonic SQL Group.
5 *
6 * Copyright (c) 1995-2000 by the Hypersonic SQL Group. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without modification, are permitted
8 * provided that the following conditions are met:
9 * - Redistributions of source code must retain the above copyright notice, this list of conditions
10 * and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright notice, this list of
12 * conditions and the following disclaimer in the documentation and/or other materials
13 * provided with the distribution.
14 * - All advertising materials mentioning features or use of this software must display the
15 * following acknowledgment: "This product includes Hypersonic SQL."
16 * - Products derived from this software may not be called "Hypersonic SQL" nor may
17 * "Hypersonic SQL" appear in their names without prior written permission of the
18 * Hypersonic SQL Group.
19 * - Redistributions of any form whatsoever must retain the following acknowledgment: "This
20 * product includes Hypersonic SQL."
21 * This software is provided "as is" and any expressed or implied warranties, including, but
22 * not limited to, the implied warranties of merchantability and fitness for a particular purpose are
23 * disclaimed. In no event shall the Hypersonic SQL Group or its contributors be liable for any
24 * direct, indirect, incidental, special, exemplary, or consequential damages (including, but
25 * not limited to, procurement of substitute goods or services; loss of use, data, or profits;
26 * or business interruption). However caused any on any theory of liability, whether in contract,
27 * strict liability, or tort (including negligence or otherwise) arising in any way out of the use of this
28 * software, even if advised of the possibility of such damage.
29 * This software consists of voluntary contributions made by many individuals on behalf of the
30 * Hypersonic SQL Group.
31 *
32 *
33 * For work added by the HSQL Development Group:
34 *
35 * Copyright (c) 2001-2002, The HSQL Development Group
36 * All rights reserved.
37 *
38 * Redistribution and use in source and binary forms, with or without
39 * modification, are permitted provided that the following conditions are met:
40 *
41 * Redistributions of source code must retain the above copyright notice, this
42 * list of conditions and the following disclaimer, including earlier
43 * license statements (above) and comply with all above license conditions.
44 *
45 * Redistributions in binary form must reproduce the above copyright notice,
46 * this list of conditions and the following disclaimer in the documentation
47 * and/or other materials provided with the distribution, including earlier
48 * license statements (above) and comply with all above license conditions.
49 *
50 * Neither the name of the HSQL Development Group nor the names of its
51 * contributors may be used to endorse or promote products derived from this
52 * software without specific prior written permission.
53 *
54 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
55 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
58 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
59 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
60 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
61 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
62 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
63 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
64 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
65 */
66
67
68 package org.hsqldb;
69
70 /**
71 * Class declaration
72 *
73 *
74 * @version 1.7.0
75 */
76 class Like {
77
78 private char cLike[];
79 private int[] iType;
80 private int iLen;
81 private boolean bIgnoreCase;
82
83 /**
84 * Constructor declaration
85 *
86 *
87 * @param s
88 * @param escape
89 * @param ignorecase
90 */
91 Like(String s, char escape, boolean ignorecase) {
92
93 if (ignorecase) {
94 s = s.toUpperCase();
95 }
96
97 normalize(s, true, escape);
98
99 bIgnoreCase = ignorecase;
100 }
101
102 /**
103 * Method declaration
104 *
105 *
106 * @return
107 */
108 String getStartsWith() {
109
110 StringBuffer s = new StringBuffer();
111 int i = 0;
112
113 for (; (i < iLen) && (iType[i] == 0); i++) {
114 s.append(cLike[i]);
115 }
116
117 if (i == 0) {
118 return null;
119 }
120
121 return s.toString();
122 }
123
124 /**
125 * Method declaration
126 *
127 *
128 * @param o
129 *
130 * @return
131 */
132 boolean compare(Object o) {
133
134 if (o == null) {
135 return iLen == 0;
136 }
137
138 String s = o.toString();
139
140 if (bIgnoreCase) {
141 s = s.toUpperCase();
142 }
143
144 return compareAt(s, 0, 0, s.length());
145 }
146
147 /**
148 * Method declaration
149 *
150 *
151 * @param s
152 * @param i
153 * @param j
154 * @param jLen
155 *
156 * @return
157 */
158 private boolean compareAt(String s, int i, int j, int jLen) {
159
160 for (; i < iLen; i++) {
161 switch (iType[i]) {
162
163 case 0 : // general character
164 if ((j >= jLen) || (cLike[i] != s.charAt(j++))) {
165 return false;
166 }
167 break;
168
169 case 1 : // underscore: do not test this character
170 if (j++ >= jLen) {
171 return false;
172 }
173 break;
174
175 case 2 : // percent: none or any character(s)
176 if (++i >= iLen) {
177 return true;
178 }
179
180 while (j < jLen) {
181 if ((cLike[i] == s.charAt(j))
182 && compareAt(s, i, j, jLen)) {
183 return true;
184 }
185
186 j++;
187 }
188
189 return false;
190 }
191 }
192
193 if (j != jLen) {
194 return false;
195 }
196
197 return true;
198 }
199
200 /**
201 * Method declaration
202 *
203 *
204 * @param s
205 * @param b
206 * @param e
207 */
208 private void normalize(String s, boolean b, char e) {
209
210 iLen = 0;
211
212 if (s == null) {
213 return;
214 }
215
216 int l = s.length();
217
218 cLike = new char[l];
219 iType = new int[l];
220
221 boolean bEscaping = false,
222 bPercent = false;
223
224 for (int i = 0; i < l; i++) {
225 char c = s.charAt(i);
226
227 if (bEscaping == false) {
228 if (b && (c == e)) {
229 bEscaping = true;
230
231 continue;
232 } else if (c == '_') {
233 iType[iLen] = 1;
234 } else if (c == '%') {
235 if (bPercent) {
236 continue;
237 }
238
239 bPercent = true;
240 iType[iLen] = 2;
241 } else {
242 bPercent = false;
243 }
244 } else {
245 bPercent = false;
246 bEscaping = false;
247 }
248
249 cLike[iLen++] = c;
250 }
251
252 for (int i = 0; i < iLen - 1; i++) {
253 if ((iType[i] == 2) && (iType[i + 1] == 1)) {
254 iType[i] = 1;
255 iType[i + 1] = 2;
256 }
257 }
258 }
259 }