type.java

linux下建立JAVA虚拟机的源码KAFFE

        while (buf[off + len] != ';') {
          ++len;
        }
        return new Type(OBJECT, buf, off, len + 1);
    }
  }

  // --------------------------------------------------------------------------
  // Accessors
  // --------------------------------------------------------------------------

  /**
   * Returns the sort of this Java type.
   *
   * @return {@link #VOID VOID}, {@link #BOOLEAN BOOLEAN}, {@link #CHAR CHAR},
   *      {@link #BYTE BYTE}, {@link #SHORT SHORT}, {@link #INT INT}, {@link
   *      #FLOAT FLOAT}, {@link #LONG LONG}, {@link #DOUBLE DOUBLE}, {@link
   *      #ARRAY ARRAY} or {@link #OBJECT OBJECT}.
   */

  public int getSort () {
    return sort;
  }

  /**
   * Returns the number of dimensions of this array type.
   * This method should only be used for an array type.
   *
   * @return the number of dimensions of this array type.
   */

  public int getDimensions () {
    int i = 1;
    while (buf[off + i] == '[') {
      ++i;
    }
    return i;
  }

  /**
   * Returns the type of the elements of this array type.
   * This method should only be used for an array type.
   *
   * @return Returns the type of the elements of this array type.
   */

  public Type getElementType () {
    return getType(buf, off + getDimensions());
  }

  /**
   * Returns the name of the class corresponding to this type.
   *
   * @return the fully qualified name of the class corresponding to this type.
   */

  public String getClassName () {
    switch (sort) {
      case VOID:    return "void";
      case BOOLEAN: return "boolean";
      case CHAR:    return "char";
      case BYTE:    return "byte";
      case SHORT:   return "short";
      case INT:     return "int";
      case FLOAT:   return "float";
      case LONG:    return "long";
      case DOUBLE:  return "double";
      case ARRAY:   
        StringBuffer b = new StringBuffer(getElementType().getClassName());
        for (int i = getDimensions(); i > 0; --i) {
          b.append("[]");
        }
        return b.toString();
      //case OBJECT:
      default:      
        return new String(buf, off + 1, len - 2).replace('/', '.');
    }
  }

  /**
   * Returns the internal name of the class corresponding to this object type.
   * The internal name of a class is its fully qualified name, where '.' are
   * replaced by '/'. This method should only be used for an object type.
   *
   * @return the internal name of the class corresponding to this object type.
   */

  public String getInternalName () {
    return new String(buf, off + 1, len - 2);
  }

  // --------------------------------------------------------------------------
  // Conversion to type descriptors
  // --------------------------------------------------------------------------

  /**
   * Returns the descriptor corresponding to this Java type.
   *
   * @return the descriptor corresponding to this Java type.
   */

  public String getDescriptor () {
    StringBuffer buf = new StringBuffer();
    getDescriptor(buf);
    return buf.toString();
  }

  /**
   * Returns the descriptor corresponding to the given argument and return
   * types.
   *
   * @param returnType the return type of the method.
   * @param argumentTypes the argument types of the method.
   * @return the descriptor corresponding to the given argument and return
   *      types.
   */

  public static String getMethodDescriptor (
    final Type returnType,
    final Type[] argumentTypes)
  {
    StringBuffer buf = new StringBuffer();
    buf.append('(');
    for (int i = 0; i < argumentTypes.length; ++i) {
      argumentTypes[i].getDescriptor(buf);
    }
    buf.append(')');
    returnType.getDescriptor(buf);
    return buf.toString();
  }

  /**
   * Appends the descriptor corresponding to this Java type to the given string
   * buffer.
   *
   * @param buf the string buffer to which the descriptor must be appended.
   */

  private void getDescriptor (final StringBuffer buf) {
    switch (sort) {
      case VOID:    buf.append('V'); return;
      case BOOLEAN: buf.append('Z'); return;
      case CHAR:    buf.append('C'); return;
      case BYTE:    buf.append('B'); return;
      case SHORT:   buf.append('S'); return;
      case INT:     buf.append('I'); return;
      case FLOAT:   buf.append('F'); return;
      case LONG:    buf.append('J'); return;
      case DOUBLE:  buf.append('D'); return;
      //case ARRAY:
      //case OBJECT:
      default:      buf.append(this.buf, off, len);
    }
  }

  // --------------------------------------------------------------------------
  // Direct conversion from classes to type descriptors,
  // without intermediate Type objects
  // --------------------------------------------------------------------------

  /**
   * Returns the internal name of the given class. The internal name of a class
   * is its fully qualified name, where '.' are replaced by '/'.
   *
   * @param c an object class.
   * @return the internal name of the given class.
   */

  public static String getInternalName (final Class c) {
    return c.getName().replace('.', '/');
  }

  /**
   * Returns the descriptor corresponding to the given Java type.
   *
   * @param c an object class, a primitive class or an array class.
   * @return the descriptor corresponding to the given class.
   */

  public static String getDescriptor (final Class c) {
    StringBuffer buf = new StringBuffer();
    getDescriptor(buf, c);
    return buf.toString();
  }

  /**
   * Returns the descriptor corresponding to the given method.
   *
   * @param m a {@link Method Method} object.
   * @return the descriptor of the given method.
   */

  public static String getMethodDescriptor (final Method m) {
    Class[] parameters = m.getParameterTypes();
    StringBuffer buf = new StringBuffer();
    buf.append('(');
    for (int i = 0; i < parameters.length; ++i) {
      getDescriptor(buf, parameters[i]);
    }
    buf.append(')');
    getDescriptor(buf, m.getReturnType());
    return buf.toString();
  }

  /**
   * Appends the descriptor of the given class to the given string buffer.
   *
   * @param buf the string buffer to which the descriptor must be appended.
   * @param c the class whose descriptor must be computed.
   */

  private static void getDescriptor (final StringBuffer buf, final Class c) {
    Class d = c;
    while (true) {
      if (d.isPrimitive()) {
        char car;
        if (d == Integer.TYPE) {
          car = 'I';
        } else if (d == Void.TYPE) {
          car = 'V';
        } else if (d == Boolean.TYPE) {
          car = 'Z';
        } else if (d == Byte.TYPE) {
          car = 'B';
        } else if (d == Character.TYPE) {
          car = 'C';
        } else if (d == Short.TYPE) {
          car = 'S';
        } else if (d == Double.TYPE) {
          car = 'D';
        } else if (d == Float.TYPE) {
          car = 'F';
        } else /*if (d == Long.TYPE)*/ {
          car = 'J';
        }
        buf.append(car);
        return;
      } else if (d.isArray()) {
        buf.append('[');
        d = d.getComponentType();
      } else {
        buf.append('L');
        String name = d.getName();
        int len = name.length();
        for (int i = 0; i < len; ++i) {
          char car = name.charAt(i);
          buf.append(car == '.' ? '/' : car);
        }
        buf.append(';');
        return;
      }
    }
  }

  // --------------------------------------------------------------------------
  // Corresponding size and opcodes
  // --------------------------------------------------------------------------

  /**
   * Returns the size of values of this type.
   *
   * @return the size of values of this type, i.e., 2 for <tt>long</tt> and
   *      <tt>double</tt>, and 1 otherwise.
   */

  public int getSize () {
    return (sort == LONG || sort == DOUBLE ? 2 : 1);
  }

  /**
   * Returns a JVM instruction opcode adapted to this Java type.
   *
   * @param opcode a JVM instruction opcode. This opcode must be one of ILOAD,
   *      ISTORE, IALOAD, IASTORE, IADD, ISUB, IMUL, IDIV, IREM, INEG, ISHL,
   *      ISHR, IUSHR, IAND, IOR, IXOR and IRETURN.
   * @return an opcode that is similar to the given opcode, but adapted to this
   *      Java type. For example, if this type is <tt>float</tt> and
   *      <tt>opcode</tt> is IRETURN, this method returns FRETURN.
   */

  public int getOpcode (final int opcode) {
    if (opcode == Constants.IALOAD || opcode == Constants.IASTORE) {
      switch (sort) {
        case BOOLEAN:
        case BYTE:
          return opcode + 5;
        case CHAR:
          return opcode + 6;
        case SHORT:
          return opcode + 7;
        case INT:
          return opcode;
        case FLOAT:
          return opcode + 2;
        case LONG:
          return opcode + 1;
        case DOUBLE:
          return opcode + 3;
        //case ARRAY:
        //case OBJECT:
        default:
          return opcode + 4;
      }
    } else {
      switch (sort) {
        case VOID:
          return opcode + 5;
        case BOOLEAN:
        case CHAR:
        case BYTE:
        case SHORT:
        case INT:
          return opcode;
        case FLOAT:
          return opcode + 2;
        case LONG:
          return opcode + 1;
        case DOUBLE:
          return opcode + 3;
        //case ARRAY:
        //case OBJECT:
        default:
          return opcode + 4;
      }
    }
  }

  // --------------------------------------------------------------------------
  // Equals, hashCode and toString
  // --------------------------------------------------------------------------

  /**
   * Tests if the given object is equal to this type.
   *
   * @param o the object to be compared to this type.
   * @return <tt>true</tt> if the given object is equal to this type.
   */

  public boolean equals (final Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || !(o instanceof Type)) {
      return false;
    }
    Type t = (Type)o;
    if (sort != t.sort) {
      return false;
    }
    if (sort == Type.OBJECT || sort == Type.ARRAY) {
      if (len != t.len) {
        return false;
      }
      for (int i = off, j = t.off, end = i + len; i < end; i++, j++) {
        if (buf[i] != t.buf[j]) {
          return false;
        }
      }
    }
    return true;
  }

  /**
   * Returns a hash code value for this type.
   *
   * @return a hash code value for this type.
   */

  public int hashCode () {
    int hc = 13 * sort;
    if (sort == Type.OBJECT || sort == Type.ARRAY) {
      for (int i = off, end = i + len; i < end; i++) {
        hc = 17 * (hc + buf[i]);
      }
    }
    return hc;
  }

  /**
   * Returns a string representation of this type.
   *
   * @return the descriptor of this type.
   */

  public String toString () {
    return getDescriptor();
  }
}