Save This Page 1 /* 2 * Copyright (c) 1995, 2004, 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 packagesun.misc; 27 28 /** 29 * A class to represent a regular expression. Only handles '*'s. 30 * @author James Gosling 31 */ 32 33 public class Regexp { 34 /** if true then the matching process ignores case. */ 35 public boolean ignoreCase; 36 37 /* 38 * regular expressions are carved into three regions: a constant string 39 * prefix, a constant string suffix, and a series of floating strings in 40 * between. In the input regular expression, they are separated by *s 41 */ 42 public String exp; 43 public String prefix, suffix; 44 public boolean exact; 45 public int prefixLen, suffixLen, totalLen; 46 public String mids[]; 47 48 /** Create a new regular expression object. The regular expression 49 is a series of constant strings separated by *s. For example: 50 <dl> 51 <dt>*.gif <dd>Matches any string that ends in ".gif". 52 <dt>/tmp/* <dd>Matches any string that starts with "/tmp/". 53 <dt>/tmp/*.gif <dd>Matches any string that starts with "/tmp/" and ends 54 with ".gif". 55 <dt>/tmp/*new*.gif <dd>Matches any string that starts with "/tmp/" 56 and ends with ".gif" and has "new" somewhere in between. 57 </dl> 58 */ 59 public Regexp (String s) { 60 exp = s; 61 int firstst = s.indexOf('*'); 62 int lastst = s.lastIndexOf('*'); 63 if (firstst < 0) { 64 totalLen = s.length(); 65 exact = true; // no * s 66 } else { 67 prefixLen = firstst; 68 if (firstst == 0) 69 prefix = null; 70 else 71 prefix = s.substring(0, firstst); 72 suffixLen = s.length() - lastst - 1; 73 if (suffixLen == 0) 74 suffix = null; 75 else 76 suffix = s.substring(lastst + 1); 77 int nmids = 0; 78 int pos = firstst; 79 while (pos < lastst && pos >= 0) { 80 nmids++; 81 pos = s.indexOf('*', pos + 1); 82 } 83 totalLen = prefixLen + suffixLen; 84 if (nmids > 0) { 85 mids = new String[nmids]; 86 pos = firstst; 87 for (int i = 0; i < nmids; i++) { 88 pos++; 89 int npos = s.indexOf('*', pos); 90 if (pos < npos) { 91 mids[i] = s.substring(pos, npos); 92 totalLen += mids[i].length(); 93 } 94 pos = npos; 95 } 96 } 97 } 98 } 99 100 /** Returns true iff the String s matches this regular expression. */ 101 final boolean matches(String s) { 102 return matches(s, 0, s.length()); 103 } 104 105 /** Returns true iff the substring of s from offset for len characters 106 matches this regular expression. */ 107 boolean matches(String s, int offset, int len) { 108 if (exact) 109 return len == totalLen && 110 exp.regionMatches(ignoreCase, 0, s, offset, len); 111 if (len < totalLen) 112 return false; 113 if (prefixLen > 0 && 114 !prefix.regionMatches(ignoreCase, 115 0, s, offset, prefixLen) 116 || 117 suffixLen > 0 && 118 !suffix.regionMatches(ignoreCase, 119 0, s, offset + len - suffixLen, 120 suffixLen)) 121 return false; 122 if (mids == null) 123 return true; 124 int nmids = mids.length; 125 int spos = offset + prefixLen; 126 int limit = offset+len-suffixLen; 127 for (int i = 0; i<nmids; i++) { 128 String ms = mids[i]; 129 int ml = ms.length(); 130 while (spos+ml<=limit && 131 !ms.regionMatches(ignoreCase, 132 0, s, spos, ml)) 133 spos++; 134 if (spos+ml>limit) 135 return false; 136 spos+=ml; 137 } 138 return true; 139 } 140 141 }