/*
 * Anarres C Preprocessor
 * Copyright (C) 2007 Shevek
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

package org.anarres.cpp;

import java.io.Reader;
import java.io.PushbackReader;
import java.io.IOException;

/* pp */ class JoinReader extends Reader {
	private Reader	in;

	private boolean	trigraphs;

	private int		newlines;
	private boolean	flushnl;
	private int[]	unget;
	private int		uptr;

	public JoinReader(Reader in, boolean trigraphs) {
		this.in = in;
		this.trigraphs = trigraphs;
		this.newlines = 0;
		this.flushnl = false;
		this.unget = new int[2];
		this.uptr = 0;
	}

	public JoinReader(Reader in) {
		this(in, false);
	}

	public void setTrigraphs(boolean enable) {
		this.trigraphs = enable;
	}

	private int __read() throws IOException {
		if (uptr > 0)
			return unget[--uptr];
		return in.read();
	}

	private void _unread(int c) {
		if (c != -1)
			unget[uptr++] = c;
	}

	private int _read() throws IOException {
		int	c = __read();
		if (c == '?' && trigraphs) {
			int d = __read();
			if (d == '?') {
				int	e = __read();
				switch (e) {
					case '(': return '[';
					case ')': return ']';
					case '<': return '{';
					case '>': return '}';
					case '=': return '#';
					case '/': return '\\';
					case '\'': return '^';
					case '!': return '|';
					case '-': return '~';
				}
				_unread(e);
			}
			_unread(d);
		}
		return c;
	}

	public int read() throws IOException {
		if (flushnl) {
			if (newlines > 0) {
				newlines--;
				return '\n';
			}
			flushnl = false;
		}

		for (;;) {
			int	c = _read();
			switch (c) {
				case '\\':
					int	d = _read();
					switch (d) {
						case '\n':
							newlines++;
							continue;
						case '\r':
							newlines++;
							int	e = _read();
							if (e != '\n')
								_unread(e);
							continue;
						default:
							_unread(d);
							return c;
					}
				case '\r':
				case '\n':
				case '\u2028':
				case '\u2029':
				case '\u000B':
				case '\u000C':
				case '\u0085':
					flushnl = true;
					return c;
				case -1:
					if (newlines > 0) {
						newlines--;
						return '\n';
					}
				default:
					return c;
			}
		}
	}

	public int read(char cbuf[], int off, int len)
						throws IOException {
		for (int i = 0; i < len; i++) {
			int	ch = read();
			if (ch == -1)
				return i;
			cbuf[off + i] = (char)ch;
		}
		return len;
	}

	public void close()
						throws IOException {
		in.close();
	}

	public String toString() {
		return "JoinReader(nl=" + newlines + ")";
	}

/*
	public static void main(String[] args) throws IOException {
		FileReader		f = new FileReader(new File(args[0]));
		BufferedReader	b = new BufferedReader(f);
		JoinReader		r = new JoinReader(b);
		BufferedWriter	w = new BufferedWriter(
				new java.io.OutputStreamWriter(System.out)
					);
		int				c;
		while ((c = r.read()) != -1) {
			w.write((char)c);
		}
		w.close();
	}
*/

}