/*
 * XML input/output support for FindBugs
 * Copyright (C) 2004, University of Maryland
 * 
 * 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.xml;

import java.io.IOException;

import edu.umd.cs.findbugs.annotations.NonNull;

/**
 * Quote metacharacters in a String.
 *
 * @see MetaCharacterMap
 * @author David Hovemeyer
 */
public abstract class QuoteMetaCharacters {
	private String text;
	private MetaCharacterMap map;

	/**
	 * Constructor.
	 *
	 * @param text the text in which we want to quote metacharacters
	 * @param map  the MetaCharacterMap
	 */
	public QuoteMetaCharacters(@NonNull String text, @NonNull MetaCharacterMap map) {
		if (text == null) throw new NullPointerException("text must be nonnull");
		if (map == null) throw new NullPointerException("map must be nonnull");
		this.text = text;
		this.map = map;
	}

	/**
	 * Quote metacharacters in the text.
	 */
	public void process() throws IOException {
		int pos = 0;
		do {
			int meta = findNextMeta(text, pos);
			if (meta >= 0) {
				emitLiteral(text.substring(pos, meta));
				emitLiteral(map.getReplacement(text.substring(meta, meta + 1)));
				pos = meta + 1;
			} else {
				emitLiteral(text.substring(pos, text.length()));
				pos = text.length();
			}
		} while (pos < text.length());
	}

	/**
	 * Downcall method to emit literal text,
	 * in which any occurrences of the metacharacters
	 * are quoted.
	 *
	 * @param s the literal text to emit
	 */
	public abstract void emitLiteral(String s) throws IOException;

	private int findNextMeta(String s, int start) {
		for (int i = start; i < s.length(); ++i) {
			char c = s.charAt(i);
			if (map.isMeta(c))
				return i;
		}
		return -1;
	}
}

// vim:ts=4