/**

 * Back 2 Browser Bytecode Translator

 * Copyright (C) 2012 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;

public final class Variable implements CharSequence {

    public static final int TYPE_INT = 0;

    public static final int TYPE_LONG = 1;

    public static final int TYPE_FLOAT = 2;

    public static final int TYPE_DOUBLE = 3;

    public static final int TYPE_REF = 4;

    public static final int LAST_TYPE = TYPE_REF;

    private static final String STACK_VAR_PREFIX = "st";

    private final String name;

    private final int type;

    private final int index;

    private static final char[] TYPE_IDS = { 'I', 'L', 'F', 'D', 'A' };

    private Variable(final String prefix, final int type, final int index) {

        this.name = prefix + TYPE_IDS[type] + index;

        this.type = type;

        this.index = index;

    }

    public static Variable getStackVariable(

            final int type, final int index) {

        // TODO: precreate frequently used variables

        return new Variable(STACK_VAR_PREFIX, type, index);

    }

    public String getName() {

        return name;

    }

    public int getType() {

        return type;

    }

    public int getIndex() {

        return index;

    }

    public boolean isCategory2() {

        return (type == TYPE_LONG) || (type == TYPE_DOUBLE);

    }

    @Override

    public int length() {

        return name.length();

    }

    @Override

    public char charAt(final int index) {

        return name.charAt(index);

    }

    @Override

    public CharSequence subSequence(final int start, final int end) {

        return name.subSequence(start, end);

    }

    @Override

    public int hashCode() {

        return name.hashCode();

    }

    @Override

    public boolean equals(final Object other) {

        if (this == other) {

            return true;

        }

        if (!(other instanceof Variable)) {

            return false;

        }

        return name.equals(((Variable) other).name);

    }

    @Override

    public String toString() {

        return name;

    }

}