intconst.java

Javassist是一个开源的分析、编辑和创建Java字节码的类库。是由东京技术学院的数学和计算机科学系的 Shigeru Chiba 所创建的。它已加入了开放源代码JBoss 应用服务器项目,通过使

/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999-2006 Shigeru Chiba. All Rights Reserved.
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License.  Alternatively, the contents of this file may be used under
 * the terms of the GNU Lesser General Public License Version 2.1 or later.
 *
 * 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 language governing rights and limitations under the
 * License.
 */

package javassist.compiler.ast;

import javassist.compiler.CompileError;
import javassist.compiler.TokenId;

/**
 * Integer constant.
 */
public class IntConst extends ASTree {
    protected long value;
    protected int type;

    public IntConst(long v, int tokenId) { value = v; type = tokenId; }

    public long get() { return value; }

    public void set(long v) { value = v; }

    /* Returns IntConstant, CharConstant, or LongConstant.
     */
    public int getType() { return type; }

    public String toString() { return Long.toString(value); }

    public void accept(Visitor v) throws CompileError {
        v.atIntConst(this);
    }

    public ASTree compute(int op, ASTree right) {
        if (right instanceof IntConst)
            return compute0(op, (IntConst)right);
        else if (right instanceof DoubleConst)
            return compute0(op, (DoubleConst)right);
        else
            return null;
    }

    private IntConst compute0(int op, IntConst right) {
        int type1 = this.type;
        int type2 = right.type;
        int newType;
        if (type1 == TokenId.LongConstant || type2 == TokenId.LongConstant)
            newType = TokenId.LongConstant;
        else if (type1 == TokenId.CharConstant
                 && type2 == TokenId.CharConstant)
            newType = TokenId.CharConstant;
        else
            newType = TokenId.IntConstant;

        long value1 = this.value;
        long value2 = right.value;
        long newValue;
        switch (op) {
        case '+' :
            newValue = value1 + value2;
            break;
        case '-' :
            newValue = value1 - value2;
            break;
        case '*' :
            newValue = value1 * value2;
            break;
        case '/' :
            newValue = value1 / value2;
            break;
        case '%' :
            newValue = value1 % value2;
            break;
        case '|' :
            newValue = value1 | value2;
            break;
        case '^' :
            newValue = value1 ^ value2;
            break;
        case '&' :
            newValue = value1 & value2;
            break;
        case TokenId.LSHIFT :
            newValue = value << (int)value2;
            newType = type1;
            break;
        case TokenId.RSHIFT :
            newValue = value >> (int)value2;
            newType = type1;
            break;
        case TokenId.ARSHIFT :
            newValue = value >>> (int)value2;
            newType = type1;
            break;
        default :
            return null;
        }

        return new IntConst(newValue, newType);
    }

    private DoubleConst compute0(int op, DoubleConst right) {
        double value1 = (double)this.value;
        double value2 = right.value;
        double newValue;
        switch (op) {
        case '+' :
            newValue = value1 + value2;
            break;
        case '-' :
            newValue = value1 - value2;
            break;
        case '*' :
            newValue = value1 * value2;
            break;
        case '/' :
            newValue = value1 / value2;
            break;
        case '%' :
            newValue = value1 % value2;
            break;
        default :
            return null;
        }

        return new DoubleConst(newValue, right.type);
    }
}