/**

 * Back 2 Browser Bytecode Translator

 * Copyright (C) 2012-2015 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 *

 * 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, version 2 of the License.

 *

 * 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. Look for COPYING file in the top folder.

 * If not, see http://opensource.org/licenses/GPL-2.0.

 */

package org.apidesign.vm4brwsr;

final class NumberOperations {

    private static final int DIV32 = 1;

    private static final int MOD32 = 2;

    private static final int MUL32 = 4;

    private int used;

    public String mul32() {

        used |= MUL32;

        return "__mul32(@1,@2)";

    }

    public String div32() {

        used |= DIV32;

        return "__div32(@1,@2)";

    }

    public String mod32() {

        used |= MOD32;

        return "__mod32(@1,@2)";

    }

    public String generate() {

        if (used == 0) {

            return "";

        }

        StringBuilder sb = new StringBuilder();

        if ((used & MUL32) != 0) {

            sb.append(

                "    __mul32 = function(x, y) {\n" +

                "        return (((x * (y >> 16)) << 16) + x * (y & 0xFFFF)) | 0;\n" +

                "    };\n" +

                ""

            );

        }

        if ((used & (MOD32 | DIV32)) != 0) {

            sb.append(

                "    function __handleDivByZero() {\n" +

                "        var exception = new vm.java_lang_ArithmeticException;\n" +

                "        vm.java_lang_ArithmeticException(false).constructor\n" +

                "          .cons__VLjava_lang_String_2.call(exception, \"/ by zero\");\n" +

                "\n" +

                "        throw exception;\n" +

                "    }\n" +

                ""

            );

        }

        if ((used & MOD32) != 0) {

            sb.append(

                "    function __mod32(x, y) {\n" +

                "        if (y === 0) __handleDivByZero();\n" +

                "        return (x % y) | 0;\n" +

                "    }\n" +

                ""

            );

        }

        if ((used & DIV32) != 0) {

            sb.append(

                "    function __div32(x, y) {\n" +

                "        if (y === 0) __handleDivByZero();\n" +

                "        return (x / y) | 0;\n" +

                "    }\n" +

                ""

            );

        }

        return sb.toString();

    }

}