/*
 * Enhydra Java Application Server Project
 * 
 * The contents of this file are subject to the Enhydra Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License on
 * the Enhydra web site ( http://www.enhydra.org/ ).
 * 
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See 
 * the License for the specific terms governing rights and limitations
 * under the License.
 * 
 * The Initial Developer of the Enhydra Application Server is Lutris
 * Technologies, Inc. The Enhydra Application Server and portions created
 * by Lutris Technologies, Inc. are Copyright Lutris Technologies, Inc.
 * All Rights Reserved.
 * 
 * Contributor(s):
 * 
 * $Id: QuotedString.java,v 1.15 2005/06/13 09:26:06 draganr Exp $
 */




package com.lutris.util;

/**
 * Static convenience class for parsing various types of quoted strings.
 */
public final class QuotedString {
    /**
     * Parse a C style quoted string.  If the first character is a quote,
     * then all characters up to a closing quote or end-of-string are
     * gathered into a new String.  The '\' character has the same 
     * semantics as in C.  That is, it literally quotes the next
     * character.  Also, the four character sequence "\<code>ddd</code>" is 
     * converted to the character represented by the octal value
     * <code>ddd</code>.
     * 
     * @param s		The string from which the quoted string is to be
     * 			parsed.
     * @return		The parsed, quoted string.
     */
    public static final
    String parseCString(String s)
    {
	return parseCString(s.toCharArray(), 0);
    }

    /**
     * Parse a C style quoted string.  If the first character is a quote,
     * then all characters up to a closing quote or end-of-string are
     * gathered into a new String.  The '\' character has the same 
     * semantics as in C.  That is, it literally quotes the next
     * character.  Also, the four character sequence "\<code>ddd</code>" is 
     * converted to the character represented by the octal value
     * <code>ddd</code>.
     * 
     * @param s		The string from which the quoted string is to be
     * 			parsed.
     * @param offset	The index into the string at which parsing is 
     * 			to begin.
     * @return		The parsed, quoted string.
     */
    public static final
    String parseCString(String s, int offset)
    {
	return parseCString(s.toCharArray(), offset);
    }
    
    /**
     * Parse a C style quoted string.  If the first character is a quote,
     * then all characters up to a closing quote or end-of-string are
     * gathered into a new String.  The '\' character has the same 
     * semantics as in C.  That is, it literally quotes the next
     * character.  Also, the four character sequence "\<code>ddd</code>" is 
     * converted to the character represented by the octal value
     * <code>ddd</code>.
     * 
     * @param c		The character array  from which the quoted string
     * 			is to be parsed.
     * @return		The parsed, quoted string.
     */
    public static final
    String parseCString(char[] c)
    {
	return parseCString(c, 0);
    }
    
    /**
     * Parse a C style quoted string.  If the first character is a quote,
     * then all characters up to a closing quote or end-of-string are
     * gathered into a new String.  The '\' character has the same 
     * semantics as in C.  That is, it literally quotes the next
     * character.  Also, the four character sequence "\<code>ddd</code>" is 
     * converted to the character represented by the octal value
     * <code>ddd</code>.
     * 
     * @param c		The character array  from which the quoted string
     * 			is to be parsed.
     * @param offset	The index into the string at which parsing is 
     * 			to begin.
     * @return		The parsed, quoted string.
     */
    public static final
    String parseCString(char[] c, int offset)
    {
	int pos, end, len;
	len = c.length;
	pos = offset;
	
	if (pos > len) return null;
	if (pos == len) return "";
	
	if (c[pos] == '"') {
	    StringBuffer b = new StringBuffer();
	    while (++pos < len) {
		switch (c[pos]) {
		    case '"':
			return new String(b);
		    case '\\':
			if (++pos >= len) {
			    b.append('\\');
			    return new String(b);
			}
			if (c[pos] == '0') {
			    if ((len - pos) >= 3) {
				String xs = new String(c, pos, 3);
				int i=-1;;
				try { i = Integer.parseInt(xs, 8); }
				catch (Throwable t) { i = -1; }
				if ((i >= 0) && (i <= 255)) {
				    b.append((char)i);
				    pos += 2;
				} else {
				    b.append(c[pos]);
				}
			    } else {
				b.append(c[pos]);
			    }
			} else {
			    b.append(c[pos]);
			}
			break;
		    default:
			b.append(c[pos]);
			break;
		}
	    }
	    return new String(b);
	} else {
	    end = pos;
	    while ((end < len) && (c[end] > ' ')) end++;
	    if ((end - pos) <= 0) return "";
	    return new String(c, pos, end - pos);
	}
    }
}