bytecode.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

     * @param n         an index into the local variable array.
     */
    public void addAstore(int n) {
        if (n < 4)
            addOpcode(75 + n);  // astore_<n>
        else if (n < 0x100) {
            addOpcode(ASTORE);          // astore
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(ASTORE);
            addIndex(n);
        }
    }

    /**
     * Appends ICONST or ICONST_&lt;n&gt;
     *
     * @param n         the pushed integer constant.
     */
    public void addIconst(int n) {
        if (n < 6 && -2 < n)
            addOpcode(3 + n);           // iconst_<i>   -1..5
        else if (n <= 127 && -128 <= n) {
            addOpcode(16);              // bipush
            add(n);
        }
        else if (n <= 32767 && -32768 <= n) {
            addOpcode(17);              // sipush
            add(n >> 8);
            add(n);
        }
        else
            addLdc(constPool.addIntegerInfo(n));
    }

    /**
     * Appends an instruction for pushing zero or null on the stack.
     * If the type is void, this method does not append any instruction.
     *
     * @param type      the type of the zero value (or null).
     */
    public void addConstZero(CtClass type) {
        if (type.isPrimitive()) {
            if (type == CtClass.longType)
                addOpcode(LCONST_0);
            else if (type == CtClass.floatType)
                addOpcode(FCONST_0);
            else if (type == CtClass.doubleType)
                addOpcode(DCONST_0);
            else if (type == CtClass.voidType)
                throw new RuntimeException("void type?");
            else
                addOpcode(ICONST_0);
        }
        else
            addOpcode(ACONST_NULL);
    }

    /**
     * Appends ILOAD or (WIDE) ILOAD_&lt;n&gt;
     *
     * @param n         an index into the local variable array.
     */
    public void addIload(int n) {
        if (n < 4)
            addOpcode(26 + n);          // iload_<n>
        else if (n < 0x100) {
            addOpcode(ILOAD);           // iload
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(ILOAD);
            addIndex(n);
        }
    }

    /**
     * Appends ISTORE or (WIDE) ISTORE_&lt;n&gt;
     *
     * @param n         an index into the local variable array.
     */
    public void addIstore(int n) {
        if (n < 4)
            addOpcode(59 + n);          // istore_<n>
        else if (n < 0x100) {
            addOpcode(ISTORE);          // istore
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(ISTORE);
            addIndex(n);
        }
    }

    /**
     * Appends LCONST or LCONST_&lt;n&gt;
     *
     * @param n         the pushed long integer constant.
     */
    public void addLconst(long n) {
        if (n == 0 || n == 1)
            addOpcode(9 + (int)n);              // lconst_<n>
        else
            addLdc2w(n);
    }

    /**
     * Appends LLOAD or (WIDE) LLOAD_&lt;n&gt;
     *
     * @param n         an index into the local variable array.
     */
    public void addLload(int n) {
        if (n < 4)
            addOpcode(30 + n);          // lload_<n>
        else if (n < 0x100) {
            addOpcode(LLOAD);           // lload
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(LLOAD);
            addIndex(n);
        }
    }

    /**
     * Appends LSTORE or LSTORE_&lt;n&gt;
     *
     * @param n         an index into the local variable array.
     */
    public void addLstore(int n) {
        if (n < 4)
            addOpcode(63 + n);          // lstore_<n>
        else if (n < 0x100) {
            addOpcode(LSTORE);          // lstore
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(LSTORE);
            addIndex(n);
        }
    }
   
    /**
     * Appends DCONST or DCONST_&lt;n&gt;
     *
     * @param d         the pushed double constant.
     */
    public void addDconst(double d) {
        if (d == 0.0 || d == 1.0)
            addOpcode(14 + (int)d);             // dconst_<n>
        else
            addLdc2w(d);
    }

    /**
     * Appends DLOAD or (WIDE) DLOAD_&lt;n&gt;
     *
     * @param n         an index into the local variable array.
     */
    public void addDload(int n) {
        if (n < 4)
            addOpcode(38 + n);          // dload_<n>
        else if (n < 0x100) {
            addOpcode(DLOAD);           // dload
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(DLOAD);
            addIndex(n);
        }
    }

    /**
     * Appends DSTORE or (WIDE) DSTORE_&lt;n&gt;
     *
     * @param n         an index into the local variable array.
     */
    public void addDstore(int n) {
        if (n < 4)
            addOpcode(71 + n);          // dstore_<n>
        else if (n < 0x100) {
            addOpcode(DSTORE);          // dstore
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(DSTORE);
            addIndex(n);
        }
    }

    /**
     * Appends FCONST or FCONST_&lt;n&gt;
     *
     * @param f         the pushed float constant.
     */
    public void addFconst(float f) {
        if (f == 0.0f || f == 1.0f || f == 2.0f)
            addOpcode(11 + (int)f);             // fconst_<n>
        else
            addLdc(constPool.addFloatInfo(f));
    }

    /**
     * Appends FLOAD or (WIDE) FLOAD_&lt;n&gt;
     *
     * @param n         an index into the local variable array.
     */
    public void addFload(int n) {
        if (n < 4)
            addOpcode(34 + n);          // fload_<n>
        else if (n < 0x100) {
            addOpcode(FLOAD);           // fload
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(FLOAD);
            addIndex(n);
        }
    }

    /**
     * Appends FSTORE or FSTORE_&lt;n&gt;
     *
     * @param n         an index into the local variable array.
     */
    public void addFstore(int n) {
        if (n < 4)
            addOpcode(67 + n);          // fstore_<n>
        else if (n < 0x100) {
            addOpcode(FSTORE);          // fstore
            add(n);
        }
        else {
            addOpcode(WIDE);
            addOpcode(FSTORE);
            addIndex(n);
        }
    }

    /**
     * Appends an instruction for loading a value from the
     * local variable at the index <code>n</code>.
     *
     * @param n         the index.
     * @param type      the type of the loaded value.
     * @return          the size of the value (1 or 2 word).
     */
    public int addLoad(int n, CtClass type) {
        if (type.isPrimitive()) {
            if (type == CtClass.booleanType || type == CtClass.charType
                || type == CtClass.byteType || type == CtClass.shortType
                || type == CtClass.intType)
                addIload(n);
            else if (type == CtClass.longType) {
                addLload(n);
                return 2;
            }
            else if(type == CtClass.floatType)
                addFload(n);
            else if(type == CtClass.doubleType) {
                addDload(n);
                return 2;
            }
            else
                throw new RuntimeException("void type?");
        }
        else
            addAload(n);

        return 1;
    }

    /**
     * Appends an instruction for storing a value into the
     * local variable at the index <code>n</code>.
     *
     * @param n         the index.
     * @param type      the type of the stored value.
     * @return          2 if the type is long or double.  Otherwise 1.
     */
    public int addStore(int n, CtClass type) {
        if (type.isPrimitive()) {
            if (type == CtClass.booleanType || type == CtClass.charType
                || type == CtClass.byteType || type == CtClass.shortType
                || type == CtClass.intType)
                addIstore(n);
            else if (type == CtClass.longType) {
                addLstore(n);
                return 2;
            }
            else if (type == CtClass.floatType)
                addFstore(n);
            else if (type == CtClass.doubleType) {
                addDstore(n);
                return 2;
            }
            else
                throw new RuntimeException("void type?");
        }
        else
            addAstore(n);

        return 1;
    }

    /**
     * Appends instructions for loading all the parameters onto the
     * operand stack.
     *
     * @param offset	the index of the first parameter.  It is 0
     *			if the method is static.  Otherwise, it is 1.
     */
    public int addLoadParameters(CtClass[] params, int offset) {
        int stacksize = 0;
        if (params != null) {
            int n = params.length;
            for (int i = 0; i < n; ++i)
                stacksize += addLoad(stacksize + offset, params[i]);
        }

        return stacksize;
    }

    /**
     * Appends CHECKCAST.
     *
     * @param c         the type.
     */
    public void addCheckcast(CtClass c) {
        addOpcode(CHECKCAST);
        addIndex(constPool.addClassInfo(c));
    }

    /**
     * Appends CHECKCAST.
     *
     * @param classname         a fully-qualified class name.
     */
    public void addCheckcast(String classname) {
        addOpcode(CHECKCAST);
        addIndex(constPool.addClassInfo(classname));
    }

    /**
     * Appends INSTANCEOF.
     *
     * @param classname         the class name.
     */
    public void addInstanceof(String classname) {
        addOpcode(INSTANCEOF);
        addIndex(constPool.addClassInfo(classname));
    }

    /**
     * Appends GETFIELD.
     *
     * @param c         the class.
     * @param name      the field name.
     * @param type      the descriptor of the field type.
     *
     * @see Descriptor#of(CtClass)
     */
    public void addGetfield(CtClass c, String name, String type) {
        add(GETFIELD);
        int ci = constPool.addClassInfo(c);
        addIndex(constPool.addFieldrefInfo(ci, name, type));
        growStack(Descriptor.dataSize(type) - 1);
    }

    /**
     * Appends GETFIELD.
     *
     * @param c         the fully-qualified class name.
     * @param name      the field name.
     * @param type      the descriptor of the field type.
     *
     * @see Descriptor#of(CtClass)
     */
    public void addGetfield(String c, String name, String type) {
        add(GETFIELD);
        int ci = constPool.addClassInfo(c);
        addIndex(constPool.addFieldrefInfo(ci, name, type));
        growStack(Descriptor.dataSize(type) - 1);
    }

    /**
     * Appends GETSTATIC.
     *
     * @param c         the class
     * @param name      the field name
     * @param type      the descriptor of the field type.
     *
     * @see Descriptor#of(CtClass)
     */
    public void addGetstatic(CtClass c, String name, String type) {
        add(GETSTATIC);
        int ci = constPool.addClassInfo(c);
        addIndex(constPool.addFieldrefInfo(ci, name, type));
        growStack(Descriptor.dataSize(type));
    }

    /**
     * Appends GETSTATIC.
     *
     * @param c         the fully-qualified class name
     * @param name      the field name
     * @param type      the descriptor of the field type.
     *
     * @see Descriptor#of(CtClass)
     */
    public void addGetstatic(String c, String name, String type) {
        add(GETSTATIC);
        int ci = constPool.addClassInfo(c);
        addIndex(constPool.addFieldrefInfo(ci, name, type));
        growStack(Descriptor.dataSize(type));
    }

    /**
     * Appends INVOKESPECIAL.
     *
     * @param clazz     the target class.
     * @param name      the method name.
     * @param returnType        the return type.
     * @param paramTypes        the parameter types.
     */
    public void addInvokespecial(CtClass clazz, String name,
                                 CtClass returnType, CtClass[] paramTypes) {
        String desc = Descriptor.ofMethod(returnType, paramTypes);
        addInvokespecial(clazz, name, desc);
    }

    /**
     * Appends INVOKESPECIAL.
     *
     * @param clazz     the target class.
     * @param name      the method name
     * @param desc      the descriptor of the method signature.
     *
     * @see Descriptor#ofMethod(CtClass,CtClass[])
     * @see Descriptor#ofConstructor(CtClass[])
     */
    public void addInvokespecial(CtClass clazz, String name, String desc) {
        addInvokespecial(constPool.addClassInfo(clazz), name, desc);
    }

    /**
     * Appends INVOKESPECIAL.
     *
     * @param clazz     the fully-qualified class name.
     * @param name      the method name
     * @param desc      the descriptor of the method signature.
     *
     * @see Descriptor#ofMethod(CtClass,CtClass[])
     * @see Descriptor#ofConstructor(CtClass[])
     */
    public void addInvokespecial(String clazz, String name, String desc) {
        addInvokespecial(constPool.addClassInfo(clazz), name, desc);
    }

    /**