/*
* Copyright 1995-2004 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package sun.misc;
/**
* A class to represent a regular expression. Only handles '*'s.
* @author James Gosling
*/
public class Regexp {
/** if true then the matching process ignores case. */
public boolean ignoreCase;
/*
* regular expressions are carved into three regions: a constant string
* prefix, a constant string suffix, and a series of floating strings in
* between. In the input regular expression, they are separated by *s
*/
public String exp;
public String prefix, suffix;
public boolean exact;
public int prefixLen, suffixLen, totalLen;
public String mids[];
/** Create a new regular expression object. The regular expression
is a series of constant strings separated by *s. For example:
<dl>
<dt>*.gif <dd>Matches any string that ends in ".gif".
<dt>/tmp/* <dd>Matches any string that starts with "/tmp/".
<dt>/tmp/*.gif <dd>Matches any string that starts with "/tmp/" and ends
with ".gif".
<dt>/tmp/*new*.gif <dd>Matches any string that starts with "/tmp/"
and ends with ".gif" and has "new" somewhere in between.
</dl>
*/
public Regexp (String s) {
exp = s;
int firstst = s.indexOf('*');
int lastst = s.lastIndexOf('*');
if (firstst < 0) {
totalLen = s.length();
exact = true; // no * s
} else {
prefixLen = firstst;
if (firstst == 0)
prefix = null;
else
prefix = s.substring(0, firstst);
suffixLen = s.length() - lastst - 1;
if (suffixLen == 0)
suffix = null;
else
suffix = s.substring(lastst + 1);
int nmids = 0;
int pos = firstst;
while (pos < lastst && pos >= 0) {
nmids++;
pos = s.indexOf('*', pos + 1);
}
totalLen = prefixLen + suffixLen;
if (nmids > 0) {
mids = new String[nmids];
pos = firstst;
for (int i = 0; i < nmids; i++) {
pos++;
int npos = s.indexOf('*', pos);
if (pos < npos) {
mids[i] = s.substring(pos, npos);
totalLen += mids[i].length();
}
pos = npos;
}
}
}
}
/** Returns true iff the String s matches this regular expression. */
final boolean matches(String s) {
return matches(s, 0, s.length());
}
/** Returns true iff the substring of s from offset for len characters
matches this regular expression. */
boolean matches(String s, int offset, int len) {
if (exact)
return len == totalLen &&
exp.regionMatches(ignoreCase, 0, s, offset, len);
if (len < totalLen)
return false;
if (prefixLen > 0 &&
!prefix.regionMatches(ignoreCase,
0, s, offset, prefixLen)
||
suffixLen > 0 &&
!suffix.regionMatches(ignoreCase,
0, s, offset + len - suffixLen,
suffixLen))
return false;
if (mids == null)
return true;
int nmids = mids.length;
int spos = offset + prefixLen;
int limit = offset+len-suffixLen;
for (int i = 0; i<nmids; i++) {
String ms = mids[i];
int ml = ms.length();
while (spos+ml<=limit &&
!ms.regionMatches(ignoreCase,
0, s, spos, ml))
spos++;
if (spos+ml>limit)
return false;
spos+=ml;
}
return true;
}
}