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/*
 * [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.antlr.tool.Grammar;

public class ActionScriptTarget extends Target {

	@Override
    public String getTargetCharLiteralFromANTLRCharLiteral(
            CodeGenerator generator,
            String literal) {

        int c = Grammar.getCharValueFromGrammarCharLiteral(literal);
        return String.valueOf(c);
    }

	@Override
    public String getTokenTypeAsTargetLabel(CodeGenerator generator,
                                            int ttype) {
        // use ints for predefined types;
        //    
        if (ttype >= 0 && ttype <= 3) {
            return String.valueOf(ttype);
        }

        String name = generator.grammar.getTokenDisplayName(ttype);

        // If name is a literal, return the token type instead
        if (name.charAt(0) == '\'') {
            return String.valueOf(ttype);
        }

        return name;
    }

    /**
     * ActionScript doesn't support Unicode String literals that are considered "illegal"
     * or are in the surrogate pair ranges.  For example "/uffff" will not encode properly
     * nor will "/ud800".  To keep things as compact as possible we use the following encoding
     * if the int is below 255, we encode as hex literal
     * If the int is between 255 and 0x7fff we use a single unicode literal with the value
     * If the int is above 0x7fff, we use a unicode literal of 0x80hh, where hh is the high-order
     * bits followed by \xll where ll is the lower order bits of a 16-bit number.
     *
     * Ideally this should be improved at a future date.  The most optimal way to encode this
     * may be a compressed AMF encoding that is embedded using an Embed tag in ActionScript.
     *
     * @param v
     */
	@Override
    public String encodeIntAsCharEscape(int v) {
        // encode as hex
        if ( v<=255 ) {
			return "\\x"+ Integer.toHexString(v|0x100).substring(1,3);
		}
        if (v <= 0x7fff) {
            String hex = Integer.toHexString(v|0x10000).substring(1,5);
		    return "\\u"+hex;
        }
        if (v > 0xffff) {
            System.err.println("Warning: character literal out of range for ActionScript target " + v);
            return "";
        }
        StringBuilder buf = new StringBuilder("\\u80");
        buf.append(Integer.toHexString((v >> 8) | 0x100).substring(1, 3)); // high - order bits
        buf.append("\\x");
        buf.append(Integer.toHexString((v & 0xff) | 0x100).substring(1, 3)); // low -order bits
        return buf.toString();
    }

    /** Convert long to two 32-bit numbers separted by a comma.
     *  ActionScript does not support 64-bit numbers, so we need to break
     *  the number into two 32-bit literals to give to the Bit.  A number like
     *  0xHHHHHHHHLLLLLLLL is broken into the following string:
     *  "0xLLLLLLLL, 0xHHHHHHHH"
	 *  Note that the low order bits are first, followed by the high order bits.
     *  This is to match how the BitSet constructor works, where the bits are
     *  passed in in 32-bit chunks with low-order bits coming first.
	 */
	@Override
	public String getTarget64BitStringFromValue(long word) {
		StringBuffer buf = new StringBuffer(22); // enough for the two "0x", "," and " "
		buf.append("0x");
        writeHexWithPadding(buf, Integer.toHexString((int)(word & 0x00000000ffffffffL)));
        buf.append(", 0x");
        writeHexWithPadding(buf, Integer.toHexString((int)(word >> 32)));

        return buf.toString();
	}

    private void writeHexWithPadding(StringBuffer buf, String digits) {
       digits = digits.toUpperCase();
		int padding = 8 - digits.length();
		// pad left with zeros
		for (int i=1; i<=padding; i++) {
			buf.append('0');
		}
		buf.append(digits);
    }

    protected ST chooseWhereCyclicDFAsGo(Tool tool,
                                                     CodeGenerator generator,
                                                     Grammar grammar,
                                                     ST recognizerST,
                                                     ST cyclicDFAST) {
        return recognizerST;
    }
}