/*******************************************************************************
* Copyright (c) 2000, 2006 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.rssowl.ui.internal.util;
import java.util.Vector;
/**
* A string pattern matcher, suppporting "*" and "?" wildcards.
*/
public class StringMatcher {
private String fPattern;
private int fLength; // pattern length
private boolean fIgnoreWildCards;
private boolean fIgnoreCase;
private boolean fHasLeadingStar;
private boolean fHasTrailingStar;
private String fSegments[]; //the given pattern is split into * separated segments
/* boundary value beyond which we don't need to search in the text */
private int fBound = 0;
private static final char fSingleWildCard = '\u0000';
private static class Position {
int start; //inclusive
int end; //exclusive
Position(int start, int end) {
this.start = start;
this.end = end;
}
int getStart() {
return start;
}
int getEnd() {
return end;
}
}
/**
* StringMatcher constructor takes in a String object that is a simple
* pattern which may contain '*' for 0 and many characters and
* '?' for exactly one character.
*
* Literal '*' and '?' characters must be escaped in the pattern
* e.g., "\*" means literal "*", etc.
*
* Escaping any other character (including the escape character itself),
* just results in that character in the pattern.
* e.g., "\a" means "a" and "\\" means "\"
*
* If invoking the StringMatcher with string literals in Java, don't forget
* escape characters are represented by "\\".
*
* @param pattern the pattern to match text against
* @param ignoreCase if true, case is ignored
* @param ignoreWildCards if true, wild cards and their escape sequences are ignored
* (everything is taken literally).
*/
public StringMatcher(String pattern, boolean ignoreCase,
boolean ignoreWildCards) {
if (pattern == null) {
throw new IllegalArgumentException();
}
fIgnoreCase = ignoreCase;
fIgnoreWildCards = ignoreWildCards;
fPattern = pattern;
fLength = pattern.length();
if (fIgnoreWildCards) {
parseNoWildCards();
} else {
parseWildCards();
}
}
/**
* Find the first occurrence of the pattern between <code>start</code)(inclusive)
* and <code>end</code>(exclusive).
* @param text the String object to search in
* @param start the starting index of the search range, inclusive
* @param end the ending index of the search range, exclusive
* @return an <code>StringMatcher.Position</code> object that keeps the starting
* (inclusive) and ending positions (exclusive) of the first occurrence of the
* pattern in the specified range of the text; return null if not found or subtext
* is empty (start==end). A pair of zeros is returned if pattern is empty string
* Note that for pattern like "*abc*" with leading and trailing stars, position of "abc"
* is returned. For a pattern like"*??*" in text "abcdf", (1,3) is returned
*/
public StringMatcher.Position find(String text, int start, int end) {
if (text == null) {
throw new IllegalArgumentException();
}
int tlen = text.length();
if (start < 0) {
start = 0;
}
if (end > tlen) {
end = tlen;
}
if (end < 0 || start >= end) {
return null;
}
if (fLength == 0) {
return new Position(start, start);
}
if (fIgnoreWildCards) {
int x = posIn(text, start, end);
if (x < 0) {
return null;
}
return new Position(x, x + fLength);
}
int segCount = fSegments.length;
if (segCount == 0) {
return new Position(start, end);
}
int curPos = start;
int matchStart = -1;
int i;
for (i = 0; i < segCount && curPos < end; ++i) {
String current = fSegments[i];
int nextMatch = regExpPosIn(text, curPos, end, current);
if (nextMatch < 0) {
return null;
}
if (i == 0) {
matchStart = nextMatch;
}
curPos = nextMatch + current.length();
}
if (i < segCount) {
return null;
}
return new Position(matchStart, curPos);
}
/**
* match the given <code>text</code> with the pattern
* @return true if matched eitherwise false
* @param text a String object
*/
public boolean match(String text) {
if(text == null) {
return false;
}
return match(text, 0, text.length());
}
/**
* Given the starting (inclusive) and the ending (exclusive) positions in the
* <code>text</code>, determine if the given substring matches with aPattern
* @return true if the specified portion of the text matches the pattern
* @param text a String object that contains the substring to match
* @param start marks the starting position (inclusive) of the substring
* @param end marks the ending index (exclusive) of the substring
*/
public boolean match(String text, int start, int end) {
if (null == text) {
throw new IllegalArgumentException();
}
if (start > end) {
return false;
}
if (fIgnoreWildCards) {
return (end - start == fLength)
&& fPattern.regionMatches(fIgnoreCase, 0, text, start,
fLength);
}
int segCount = fSegments.length;
if (segCount == 0 && (fHasLeadingStar || fHasTrailingStar)) {
return true;
}
if (start == end) {
return fLength == 0;
}
if (fLength == 0) {
return start == end;
}
int tlen = text.length();
if (start < 0) {
start = 0;
}
if (end > tlen) {
end = tlen;
}
int tCurPos = start;
int bound = end - fBound;
if (bound < 0) {
return false;
}
int i = 0;
String current = fSegments[i];
int segLength = current.length();
/* process first segment */
if (!fHasLeadingStar) {
if (!regExpRegionMatches(text, start, current, 0, segLength))
return false;
++i;
tCurPos = tCurPos + segLength;
}
if ((fSegments.length == 1) && (!fHasLeadingStar)
&& (!fHasTrailingStar)) {
// only one segment to match, no wildcards specified
return tCurPos == end;
}
/* process middle segments */
while (i < segCount) {
current = fSegments[i];
int currentMatch;
int k = current.indexOf(fSingleWildCard);
if (k < 0) {
currentMatch = textPosIn(text, tCurPos, end, current);
if (currentMatch < 0) {
return false;
}
} else {
currentMatch = regExpPosIn(text, tCurPos, end, current);
if (currentMatch < 0) {
return false;
}
}
tCurPos = currentMatch + current.length();
i++;
}
/* process final segment */
if (!fHasTrailingStar && tCurPos != end) {
int clen = current.length();
return regExpRegionMatches(text, end - clen, current, 0, clen);
}
return i == segCount;
}
/**
* This method parses the given pattern into segments seperated by wildcard '*' characters.
* Since wildcards are not being used in this case, the pattern consists of a single segment.
*/
private void parseNoWildCards() {
fSegments = new String[1];
fSegments[0] = fPattern;
fBound = fLength;
}
/**
* Parses the given pattern into segments seperated by wildcard '*' characters.
* @param p a String object that is a simple regular expression with '*' and/or '?'
*/
@SuppressWarnings("unchecked")
private void parseWildCards() {
if (fPattern.startsWith("*")) { //$NON-NLS-1$
fHasLeadingStar = true;
}
if (fPattern.endsWith("*")) {//$NON-NLS-1$
/* make sure it's not an escaped wildcard */
if (fLength > 1 && fPattern.charAt(fLength - 2) != '\\') {
fHasTrailingStar = true;
}
}
Vector temp = new Vector();
int pos = 0;
StringBuilder buf = new StringBuilder();
while (pos < fLength) {
char c = fPattern.charAt(pos++);
switch (c) {
case '\\':
if (pos >= fLength) {
buf.append(c);
} else {
char next = fPattern.charAt(pos++);
/* if it's an escape sequence */
if (next == '*' || next == '?' || next == '\\') {
buf.append(next);
} else {
/* not an escape sequence, just insert literally */
buf.append(c);
buf.append(next);
}
}
break;
case '*':
if (buf.length() > 0) {
/* new segment */
temp.addElement(buf.toString());
fBound += buf.length();
buf.setLength(0);
}
break;
case '?':
/* append special character representing single match wildcard */
buf.append(fSingleWildCard);
break;
default:
buf.append(c);
}
}
/* add last buffer to segment list */
if (buf.length() > 0) {
temp.addElement(buf.toString());
fBound += buf.length();
}
fSegments = new String[temp.size()];
temp.copyInto(fSegments);
}
/**
* @param text a string which contains no wildcard
* @param start the starting index in the text for search, inclusive
* @param end the stopping point of search, exclusive
* @return the starting index in the text of the pattern , or -1 if not found
*/
protected int posIn(String text, int start, int end) {//no wild card in pattern
int max = end - fLength;
if (!fIgnoreCase) {
int i = text.indexOf(fPattern, start);
if (i == -1 || i > max) {
return -1;
}
return i;
}
for (int i = start; i <= max; ++i) {
if (text.regionMatches(true, i, fPattern, 0, fLength)) {
return i;
}
}
return -1;
}
/**
* @param text a simple regular expression that may only contain '?'(s)
* @param start the starting index in the text for search, inclusive
* @param end the stopping point of search, exclusive
* @param p a simple regular expression that may contains '?'
* @return the starting index in the text of the pattern , or -1 if not found
*/
protected int regExpPosIn(String text, int start, int end, String p) {
int plen = p.length();
int max = end - plen;
for (int i = start; i <= max; ++i) {
if (regExpRegionMatches(text, i, p, 0, plen)) {
return i;
}
}
return -1;
}
/**
*
* @return boolean
* @param text a String to match
* @param tStart int that indicates the starting index of match, inclusive
* @param p String, String, a simple regular expression that may contain '?'
* @param pStart
* @param plen
*/
protected boolean regExpRegionMatches(String text, int tStart, String p,
int pStart, int plen) {
while (plen-- > 0) {
char tchar = text.charAt(tStart++);
char pchar = p.charAt(pStart++);
/* process wild cards */
if (!fIgnoreWildCards) {
/* skip single wild cards */
if (pchar == fSingleWildCard) {
continue;
}
}
if (pchar == tchar) {
continue;
}
if (fIgnoreCase) {
if (Character.toUpperCase(tchar) == Character
.toUpperCase(pchar)) {
continue;
}
// comparing after converting to upper case doesn't handle all cases;
// also compare after converting to lower case
if (Character.toLowerCase(tchar) == Character
.toLowerCase(pchar)) {
continue;
}
}
return false;
}
return true;
}
/**
* @param text the string to match
* @param start the starting index in the text for search, inclusive
* @param end the stopping point of search, exclusive
* @param p a string that has no wildcard
* @return the starting index in the text of the pattern , or -1 if not found
*/
protected int textPosIn(String text, int start, int end, String p) {
int plen = p.length();
int max = end - plen;
if (!fIgnoreCase) {
int i = text.indexOf(p, start);
if (i == -1 || i > max) {
return -1;
}
return i;
}
for (int i = start; i <= max; ++i) {
if (text.regionMatches(true, i, p, 0, plen)) {
return i;
}
}
return -1;
}
}