package net.sourceforge.phpdt.externaltools.model;
/**********************************************************************
Copyright (c) 2000, 2002 IBM Corp.  All rights reserved.
This file is made available under the terms of the Common Public License v1.0
which accompanies this distribution, and is available at
http://www.eclipse.org/legal/cpl-v10.html
**********************************************************************/

import java.util.Vector;

/**
 * Copied from net.sourceforge.phpdt.internal.ui.util.StringMatcher
 * 
 *  A string pattern matcher, suppporting * and ? wildcards.
 */
public class StringMatcher {
	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';

	public static class Position {
		int start; //inclusive
		int end; //exclusive
		public Position(int start, int end) {
			this.start= start;
			this.end= end;
		}
		public int getStart() {
			return start;
		}
		public 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 <code>text</code>, the String object to search in
	 * @param <code>start</code>, the starting index of the search range, inclusive
	 * @param <code>end</code>, 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)//pattern contains only '*'(s)
			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 <code>text</code>, 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 String <code>text</code>, a String object that contains the substring to match
	 * @param int <code>start<code> marks the starting position (inclusive) of the substring
	 * @param int <code>end<code> 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))  // pattern 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;
			}
		}

		/* 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 �?�
	 */
	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;
		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);
	}
	/**
	 * @param <code>text</code>, a string which contains no wildcard
	 * @param <code>start</code>, the starting index in the text for search, inclusive
	 * @param <code>end</code>, 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 <code>text</code>, a simple regular expression that may only contain '?'(s)
	 * @param <code>start</code>, the starting index in the text for search, inclusive
	 * @param <code>end</code>, the stopping point of search, exclusive
	 * @param <code>p</code>, a simple regular expression that may contains '?'
	 * @param <code>caseIgnored</code>, wether the pattern is not casesensitive
	 * @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 <code>text</code>, a String to match
	 * @param <code>start</code>, int that indicates the starting index of match, inclusive
	 * @param <code>end</code> int that indicates the ending index of match, exclusive
	 * @param <code>p</code>, String,  String, a simple regular expression that may contain '?'
	 * @param <code>ignoreCase</code>, boolean indicating wether code>p</code> is case sensitive
	 */
	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 <code>text</code>, the string to match
	 * @param <code>start</code>, the starting index in the text for search, inclusive
	 * @param <code>end</code>, the stopping point of search, exclusive
	 * @param code>p</code>, a string that has no wildcard
	 * @param <code>ignoreCase</code>, boolean indicating wether code>p</code> is case sensitive
	 * @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;
	}
}