/*
* gnu/regexp/REMatch.java
* Copyright (C) 1998-2001 Wes Biggs
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
package gnu.regexp;
import java.io.Serializable;
/**
* An instance of this class represents a match
* completed by a gnu.regexp matching function. It can be used
* to obtain relevant information about the location of a match
* or submatch.
*
* @author <A HREF="mailto:wes@cacas.org">Wes Biggs</A>
*/
public final class REMatch implements Serializable, Cloneable {
private String matchedText;
// These variables are package scope for fast access within the engine
int eflags; // execution flags this match was made using
// Offset in source text where match was tried. This is zero-based;
// the actual position in the source text is given by (offset + anchor).
int offset;
// Anchor position refers to the index into the source input
// at which the matching operation began.
// This is also useful for the ANCHORINDEX option.
int anchor;
// Package scope; used by RE.
int index; // used while matching to mark current match position in input
int[] start; // start positions (relative to offset) for each (sub)exp.
int[] end; // end positions for the same
REMatch next; // other possibility (to avoid having to use arrays)
public Object clone() {
try {
REMatch copy = (REMatch) super.clone();
copy.next = null;
// Jun 25 2003 3:39 PM PG
// Work around problem with jikes 1.18 and IBM Java 1.4.1.
//copy.start = (int[]) start.clone();
//copy.end = (int[]) end.clone();
copy.start = new int[start.length];
System.arraycopy(start, 0, copy.start, 0, start.length);
copy.end = new int[end.length];
System.arraycopy(end, 0, copy.end, 0, end.length);
return copy;
} catch (CloneNotSupportedException e) {
throw new Error(); // doesn't happen
}
}
void assignFrom(REMatch other) {
start = other.start;
end = other.end;
index = other.index;
// need to deep clone?
next = other.next;
}
REMatch(int subs, int anchor, int eflags) {
start = new int[subs+1];
end = new int[subs+1];
this.anchor = anchor;
this.eflags = eflags;
clear(anchor);
}
void finish(CharIndexed text) {
start[0] = 0;
StringBuffer sb = new StringBuffer();
int i;
for (i = 0; i < end[0]; i++)
sb.append(text.charAt(i));
matchedText = sb.toString();
for (i = 0; i < start.length; i++) {
// If any subexpressions didn't terminate, they don't count
// TODO check if this code ever gets hit
if ((start[i] == -1) ^ (end[i] == -1)) {
start[i] = -1;
end[i] = -1;
}
}
next = null; // cut off alternates
}
/** Clears the current match and moves the offset to the new index. */
void clear(int index) {
offset = index;
this.index = 0;
for (int i = 0; i < start.length; i++) {
start[i] = end[i] = -1;
}
next = null; // cut off alternates
}
/**
* Returns the string matching the pattern. This makes it convenient
* to write code like the following:
* <P>
* <code>
* REMatch myMatch = myExpression.getMatch(myString);<br>
* if (myMatch != null) System.out.println("Regexp found: "+myMatch);
* </code>
*/
public String toString() {
return matchedText;
}
/**
* Returns the index within the input text where the match in its entirety
* began.
*/
public int getStartIndex() {
return offset + start[0];
}
/**
* Returns the index within the input string where the match in
* its entirety ends. The return value is the next position after
* the end of the string; therefore, a match created by the
* following call:
*
* <P>
* <code>REMatch myMatch = myExpression.getMatch(myString);</code>
* <P>
* can be viewed (given that myMatch is not null) by creating
* <P>
* <code>String theMatch = myString.substring(myMatch.getStartIndex(),
* myMatch.getEndIndex());</code>
* <P>
* But you can save yourself that work, since the <code>toString()</code>
* method (above) does exactly that for you.
*/
public int getEndIndex() {
return offset + end[0];
}
/**
* Returns the string matching the given subexpression. The subexpressions
* are indexed starting with one, not zero. That is, the subexpression
* identified by the first set of parentheses in a regular expression
* could be retrieved from an REMatch by calling match.toString(1).
*
* @param sub Index of the subexpression.
*/
public String toString(int sub) {
if ((sub >= start.length) || (start[sub] == -1)) return "";
return (matchedText.substring(start[sub],end[sub]));
}
/**
* Returns the index within the input string used to generate this match
* where subexpression number <i>sub</i> begins, or <code>-1</code> if
* the subexpression does not exist. The initial position is zero.
*
* @param sub Subexpression index
* @deprecated Use getStartIndex(int) instead.
*/
public int getSubStartIndex(int sub) {
if (sub >= start.length) return -1;
int x = start[sub];
return (x == -1) ? x : offset + x;
}
/**
* Returns the index within the input string used to generate this match
* where subexpression number <i>sub</i> begins, or <code>-1</code> if
* the subexpression does not exist. The initial position is zero.
*
* @param sub Subexpression index
* @since gnu.regexp 1.1.0
*/
public int getStartIndex(int sub) {
if (sub >= start.length) return -1;
int x = start[sub];
return (x == -1) ? x : offset + x;
}
/**
* Returns the index within the input string used to generate this match
* where subexpression number <i>sub</i> ends, or <code>-1</code> if
* the subexpression does not exist. The initial position is zero.
*
* @param sub Subexpression index
* @deprecated Use getEndIndex(int) instead
*/
public int getSubEndIndex(int sub) {
if (sub >= start.length) return -1;
int x = end[sub];
return (x == -1) ? x : offset + x;
}
/**
* Returns the index within the input string used to generate this match
* where subexpression number <i>sub</i> ends, or <code>-1</code> if
* the subexpression does not exist. The initial position is zero.
*
* @param sub Subexpression index
*/
public int getEndIndex(int sub) {
if (sub >= start.length) return -1;
int x = end[sub];
return (x == -1) ? x : offset + x;
}
/**
* Substitute the results of this match to create a new string.
* This is patterned after PERL, so the tokens to watch out for are
* <code>$0</code> through <code>$9</code>. <code>$0</code> matches
* the full substring matched; <code>$<i>n</i></code> matches
* subexpression number <i>n</i>.
*
* @param input A string consisting of literals and <code>$<i>n</i></code> tokens.
*/
public String substituteInto(String input) {
// a la Perl, $0 is whole thing, $1 - $9 are subexpressions
StringBuffer output = new StringBuffer();
int pos;
for (pos = 0; pos < input.length()-1; pos++) {
if ((input.charAt(pos) == '$') && (Character.isDigit(input.charAt(pos+1)))) {
int val = Character.digit(input.charAt(++pos),10);
if (val < start.length) {
output.append(toString(val));
}
} else output.append(input.charAt(pos));
}
if (pos < input.length()) output.append(input.charAt(pos));
return output.toString();
}
}
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