/*
 * [The "BSD license"]
 *  Copyright (c) 2010 Terence Parr
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *      derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.antlr.codegen;

import org.antlr.Tool;
import org.stringtemplate.v4.ST;
import org.stringtemplate.v4.STGroup;
import org.antlr.tool.Grammar;

import java.io.IOException;

public class CPPTarget extends Target {
	
	public String escapeChar( int c ) {
		// System.out.println("CPPTarget.escapeChar("+c+")");
		switch (c) {
		case '\n' : return "\\n";
		case '\t' : return "\\t";
		case '\r' : return "\\r";
		case '\\' : return "\\\\";
		case '\'' : return "\\'";
		case '"' :  return "\\\"";
		default :
			if ( c < ' ' || c > 126 )
			{
				if (c > 255)
				{
					String s = Integer.toString(c,16);
					// put leading zeroes in front of the thing..
					while( s.length() < 4 )
						s = '0' + s;
					return "\\u" + s;
				}
				else {
					return "\\" + Integer.toString(c,8);
				}
			}
			else {
				return String.valueOf((char)c);
			}
		}
	}

	/** Converts a String into a representation that can be use as a literal
	 * when surrounded by double-quotes.
	 *
	 * Used for escaping semantic predicate strings for exceptions.
	 *
	 * @param s The String to be changed into a literal
	 */
	public String escapeString(String s)
	{
		StringBuffer retval = new StringBuffer();
		for (int i = 0; i < s.length(); i++) {
			retval.append(escapeChar(s.charAt(i)));
		}

		return retval.toString();
	}

	protected void genRecognizerHeaderFile(Tool tool,
										   CodeGenerator generator,
										   Grammar grammar,
										   ST headerFileST,
										   String extName)
		throws IOException
	{
		generator.write(headerFileST, grammar.name+extName);
	}

	/** Convert from an ANTLR char literal found in a grammar file to
	 *  an equivalent char literal in the target language.  For Java, this
	 *  is the identify translation; i.e., '\n' -> '\n'.  Most languages
	 *  will be able to use this 1-to-1 mapping.  Expect single quotes
	 *  around the incoming literal.
	 *  Depending on the charvocabulary the charliteral should be prefixed with a 'L'
	 */
	public String getTargetCharLiteralFromANTLRCharLiteral( CodeGenerator codegen, String literal) {
		int c = Grammar.getCharValueFromGrammarCharLiteral(literal);
		String prefix = "'";
		if( codegen.grammar.getMaxCharValue() > 255 )
			prefix = "L'";
		else if( (c & 0x80) != 0 )	// if in char mode prevent sign extensions
			return ""+c;
		return prefix+escapeChar(c)+"'";
	}

	/** Convert from an ANTLR string literal found in a grammar file to
	 *  an equivalent string literal in the target language.  For Java, this
	 *  is the identify translation; i.e., "\"\n" -> "\"\n".  Most languages
	 *  will be able to use this 1-to-1 mapping.  Expect double quotes 
	 *  around the incoming literal.
	 *  Depending on the charvocabulary the string should be prefixed with a 'L'
	 */
	public String getTargetStringLiteralFromANTLRStringLiteral( CodeGenerator codegen, String literal) {
		StringBuffer buf = Grammar.getUnescapedStringFromGrammarStringLiteral(literal);
		String prefix = "\"";
		if( codegen.grammar.getMaxCharValue() > 255 )
			prefix = "L\"";
		return prefix+escapeString(buf.toString())+"\"";
	}
	/** Character constants get truncated to this value.
	 * TODO: This should be derived from the charVocabulary. Depending on it
	 * being 255 or 0xFFFF the templates should generate normal character
	 * constants or multibyte ones.
	 */
	public int getMaxCharValue( CodeGenerator codegen ) {
		int maxval = 255; // codegen.grammar.get????();
		if ( maxval <= 255 )
			return 255;
		else
			return maxval;
	}
}