/*
* gnu/regexp/REMatch.java
* Copyright (C) 1998 Wes Biggs
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as published
* by the Free Software Foundation; either version 2 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 Library General Public License for more details.
*
* You should have received a copy of the GNU Library 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;
/**
* 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 class REMatch {
private String m_match;
int offset, anchor;
int[] start; // package scope for
int[] end; // quick access internally
int[] count; // runtime count of times through each subexpression
REMatch(int f_subs, int f_index) {
start = new int[f_subs+1];
end = new int[f_subs+1];
count = new int[f_subs+1];
anchor = f_index;
clear(f_index);
}
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));
m_match = sb.toString();
for (i = 0; i < start.length; i++) {
if (start[i] == -1) end[i] = -1;
}
}
void reset(int f_subIndex) {
for (int i = f_subIndex; i < start.length; i++) {
start[i] = end[i] = -1;
count[i] = 0;
}
}
void clear(int f_index) {
offset = f_index;
for (int i = 0; i < start.length; i++) {
start[i] = end[i] = -1;
count[i] = 0;
}
}
/**
* 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 m_match;
}
/**
* 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.
*
* @param sub Index of the subexpression.
*/
public String toString(int sub) {
if ((sub >= start.length) || (start[sub] == -1)) return "";
return (m_match.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.
*
* @param sub Subexpression index
*/
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> ends, or <code>-1</code> if
* the subexpression does not exist.
*
* @param sub Subexpression index
*/
public int getSubEndIndex(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();
}
}