/*
* Copyright (c) 2011, the Dart project authors.
*
* Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.eclipse.org/legal/epl-v10.html
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.dart.tools.ui.internal.util;
import java.util.Vector;
/**
* A string pattern matcher. Supports '*' and '?' wildcards.
*/
public class StringMatcher {
public static class Position {
int start; // inclusive
int end; // exclusive
public Position(int start, int end) {
this.start = start;
this.end = end;
}
public int getEnd() {
return end;
}
public int getStart() {
return start;
}
}
protected String fPattern;
protected int fLength; // pattern length
protected boolean fIgnoreWildCards;
protected boolean fIgnoreCase;
protected boolean fHasLeadingStar;
protected boolean fHasTrailingStar;
protected String fSegments[]; // the given pattern is split into * separated
// segments
/* boundary value beyond which we don't need to search in the text */
protected int fBound = 0;
protected static final char fSingleWildCard = '\u0000';
/**
* StringMatcher constructor takes in a String object that is a simple pattern. The pattern 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) {
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)) {
// contains only '*'(s)
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;
} else {
++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;
}
/**
* @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;
}
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;
}
/**
* 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.
*/
private void parseWildCards() {
if (fPattern.startsWith("*")) {
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<String> temp = new Vector<String>();
int pos = 0;
StringBuffer buf = new StringBuffer();
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);
}
}