/* 
 
Copyright 2006 Rene Grothmann, modified by Eric Hakenholz

This file is part of C.a.R. software.

    C.a.R. is a 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, version 3 of the License.

    C.a.R. 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, see <http://www.gnu.org/licenses/>.
 
 */
 
 
 package rene.util.parser;

import java.util.Vector;

/**
 * This is a string simple parser.
 */

public class StringParser {
	char C[];
	int N, L;
	boolean Error;

	/**
	 * @param S
	 *            the string to be parsed.
	 */
	public StringParser(final String S) {
		C = S.toCharArray();
		N = 0;
		L = C.length;
		Error = (N >= L);
	}

	/**
	 * @return next character is white?
	 */
	public boolean blank() {
		return (C[N] == ' ' || C[N] == '\t' || C[N] == '\n' || C[N] == '\r');
	}

	/**
	 * @return next character is white or c?
	 */
	public boolean blank(final char c) {
		return (C[N] == ' ' || C[N] == '\t' || C[N] == '\n' || C[N] == '\r' || C[N] == c);
	}

	/**
	 * Cut off the String upto a character c.
	 */
	public String upto(final char c) {
		if (Error)
			return "";
		int n = N;
		while (n < L && C[n] != c)
			n++;
		if (n >= L)
			Error = true;
		final String s = new String(C, N, n - N);
		N = n;
		return s;
	}

	/**
	 * Advance one character.
	 * 
	 * @return String is not empty.
	 */
	public boolean advance() {
		if (N < L)
			N++;
		if (N >= L)
			Error = true;
		return !Error;
	}

	/**
	 * Parse a word up to a blank.
	 */
	public String parseword() {
		if (Error)
			return "";
		while (blank()) {
			if (!advance())
				return "";
		}
		final int n = N;
		while (!Error && !blank())
			advance();
		return new String(C, n, N - n);
	}

	/**
	 * Parse digits upto the character c or blank.
	 */
	public String parsedigits(final char c) {
		if (Error)
			return "";
		while (blank()) {
			if (!advance())
				return "";
		}
		final int n = N;
		while (!Error && !blank()) {
			if (N > L || C[N] < '0' || C[N] > '9' || C[N] == c)
				break;
			advance();
		}
		return new String(C, n, N - n);
	}

	/**
	 * Parse digits upto a blank.
	 */
	public String parsedigits() {
		if (Error)
			return "";
		while (blank()) {
			if (!advance())
				return "";
		}
		final int n = N;
		while (!Error && !blank()) {
			if (N > L || C[N] < '0' || C[N] > '9')
				break;
			advance();
		}
		return new String(C, n, N - n);
	}

	/**
	 * Parse a word upto the character c or blank.
	 */
	public String parseword(final char c) {
		if (Error)
			return "";
		while (blank()) {
			if (!advance())
				return "";
		}
		final int n = N;
		while (!Error && !blank(c))
			advance();
		return new String(C, n, N - n);
	}

	/**
	 * @return next character is a digit?
	 */
	public boolean isint() {
		if (Error)
			return false;
		return (C[N] >= '0' && C[N] <= '9');
	}

	/**
	 * Parse an int upto a blank. The int may be negative.
	 * 
	 * @return the int
	 */
	public int parseint() {
		int sig = 1;
		try {
			skipblanks();
			if (Error)
				return 0;
			if (C[N] == '-') {
				sig = -1;
				N++;
				if (N > L) {
					Error = true;
					return 0;
				}
			}
			return sig * Integer.parseInt(parsedigits(), 10);
		} catch (final NumberFormatException e) {
			return 0;
		}
	}

	/**
	 * Parse an int upto a blank or c. The int may be negative.
	 * 
	 * @return the int
	 */
	public int parseint(final char c) {
		int sig = 1;
		try {
			skipblanks();
			if (Error)
				return 0;
			if (C[N] == '-') {
				sig = -1;
				N++;
				if (N > L) {
					Error = true;
					return 0;
				}
			}
			return sig * Integer.parseInt(parsedigits(c), 10);
		} catch (final NumberFormatException e) {
			return 0;
		}
	}

	/**
	 * Skip all white characters.
	 */
	public void skipblanks() {
		if (Error)
			return;
		while (blank())
			if (!advance())
				break;
	}

	/**
	 * Skip everything to the string s.
	 * 
	 * @return String was found
	 */
	public boolean skip(final String s) {
		if (Error)
			return false;
		final int l = s.length();
		if (N + l > L)
			return false;
		if (!new String(C, N, l).equals(s))
			return false;
		N += l;
		if (N >= L)
			Error = true;
		return true;
	}

	/**
	 * Get the next character.
	 */
	public char next() {
		if (Error)
			return ' ';
		else {
			N++;
			if (N >= L) {
				Error = true;
			}
			return C[N - 1];
		}
	}

	/**
	 * Return a String, which is parsed from words with limited length.
	 * 
	 * @param columns
	 *            the maximal length of the string
	 */
	public String wrapline(final int columns) {
		int n = N, good = N;
		String s = "";
		while (n < L) {
			if (C[n] == '\n') {
				if (n > N)
					s = new String(C, N, n - N);
				N = n + 1;
				break;
			}
			if (C[n] == ' ' || C[n] == '\t' || C[n] == '\n') {
				good = n;
			}
			n++;
			if (n - N >= columns && good > N) {
				s = new String(C, N, good - N);
				N = good + 1;
				break;
			}
			if (n >= L) {
				if (n > N)
					s = new String(C, N, n - N);
				N = n;
				break;
			}
		}
		if (N >= L)
			Error = true;
		return s;
	}

	/**
	 * Parse the string into lines.
	 * 
	 * @param columns
	 *            the maximal length of each line
	 * @return a Vector with lines
	 */
	public Vector wraplines(final int columns) {
		final Vector v = new Vector(10, 10);
		String s;
		while (!Error) {
			s = wrapline(columns);
			v.addElement(s);
		}
		return v;
	}

	public String wraplineword(final int columns) {
		int n = N;
		final int good = N;
		String s = "";
		while (n < L) {
			if (C[n] == '\n') {
				s = new String(C, N, n - N);
				N = n + 1;
				break;
			}
			n++;
			if (n >= L) {
				if (n > N)
					s = new String(C, N, n - N);
				N = n;
				break;
			}
			if (n - N >= columns && good > N) {
				s = new String(C, N, good - N);
				N = good + 1;
				if (N < L && C[N] != '\n')
					s = s + "\\";
				break;
			}
		}
		if (N >= L)
			Error = true;
		return s;
	}

	public Vector wrapwords(final int columns) {
		final Vector v = new Vector(10, 10);
		String s;
		while (!Error) {
			s = wraplineword(columns);
			v.addElement(s);
		}
		return v;
	}

	/**
	 * Replace c1 by c2
	 */
	public void replace(final char c1, final char c2) {
		for (int i = 0; i < L; i++)
			if (C[i] == c1)
				C[i] = c2;
	}

	/**
	 * @return if an error has occured during the parsing.
	 */
	public boolean error() {
		return Error;
	}
}