dataoutputstream.java

linux下建立JAVA虚拟机的源码KAFFE

   * the high byte written first in the following manner:
   * <p>
   * <code>byte0 = (byte)((value & 0xFF000000) >> 24);<br>
   * byte1 = (byte)((value & 0x00FF0000) >> 16);<br>
   * byte2 = (byte)((value & 0x0000FF00) >> 8);<br>
   * byte3 = (byte)(value & 0x000000FF);</code>
   * <p>
   *
   * The value written can be read using the <code>readInt</code>
   * method in <code>DataInput</code>.
   *
   * @param value The <code>int</code> value to write to the stream
   *
   * @exception IOException If an error occurs
   *
   * @see DataInput#readInt
   */
  public final synchronized void writeInt (int value) throws IOException
  {
    write ((byte) (0xff & (value >> 24)));
    write ((byte) (0xff & (value >> 16)));
    write ((byte) (0xff & (value >>  8)));
    write ((byte) (0xff & value));
  }

  /**
   * This method writes a Java long value to an output stream.  The 8 bytes
   * of the passed value will be written "big endian".  That is, with
   * the high byte written first in the following manner:
   * <p>
   * <code>byte0 = (byte)((value & 0xFF00000000000000L) >> 56);<br>
   * byte1 = (byte)((value & 0x00FF000000000000L) >> 48);<br>
   * byte2 = (byte)((value & 0x0000FF0000000000L) >> 40);<br>
   * byte3 = (byte)((value & 0x000000FF00000000L) >> 32);<br>
   * byte4 = (byte)((value & 0x00000000FF000000L) >> 24);<br>
   * byte5 = (byte)((value & 0x0000000000FF0000L) >> 16);<br>
   * byte6 = (byte)((value & 0x000000000000FF00L) >> 8);<br>
   * byte7 = (byte)(value & 0x00000000000000FFL);</code>
   * <p>
   *
   * The value written can be read using the <code>readLong</code>
   * method in <code>DataInput</code>.
   *
   * @param value The <code>long</code> value to write to the stream
   *
   * @exception IOException If an error occurs
   *
   * @see DataInput#readLong
   */
  public final synchronized void writeLong (long value) throws IOException
  {
    write ((byte) (0xff & (value >> 56)));
    write ((byte) (0xff & (value>> 48)));
    write ((byte) (0xff & (value>> 40)));
    write ((byte) (0xff & (value>> 32)));
    write ((byte) (0xff & (value>> 24)));
    write ((byte) (0xff & (value>> 16)));
    write ((byte) (0xff & (value>>  8)));
    write ((byte) (0xff & value));
  }

  /**
   * This method writes a Java <code>float</code> value to the stream.  This
   * value is written by first calling the method
   * <code>Float.floatToIntBits</code>
   * to retrieve an <code>int</code> representing the floating point number,
   * then writing this <code>int</code> value to the stream exactly the same
   * as the <code>writeInt()</code> method does.
   *
   * The value written can be read using the <code>readFloat</code>
   * method in <code>DataInput</code>.
   *
   * @param value The <code>float</code> value to write to the stream
   *
   * @exception IOException If an error occurs
   *
   * @see #writeInt(int)
   * @see DataInput#readFloat
   * @see Float#floatToIntBits
   */
  public final void writeFloat (float value) throws IOException
  {
    writeInt (Float.floatToIntBits (value));
  }

  /**
   * This method writes a Java <code>double</code> value to the stream.  This
   * value is written by first calling the method
   * <code>Double.doubleToLongBits</code>
   * to retrieve an <code>long</code> representing the floating point number,
   * then writing this <code>long</code> value to the stream exactly the same
   * as the <code>writeLong()</code> method does.
   *
   * The value written can be read using the <code>readDouble</code>
   * method in <code>DataInput</code>.
   *
   * @param value The <code>double</code> value to write to the stream
   *
   * @exception IOException If an error occurs
   *
   * @see #writeLong(long)
   * @see DataInput#readDouble
   * @see Double#doubleToLongBits
   */
  public final void writeDouble (double value) throws IOException
  {
    writeLong (Double.doubleToLongBits (value));
  }

  /**
   * This method writes all the bytes in a <code>String</code> out to the
   * stream.  One byte is written for each character in the
   * <code>String</code>.
   * The high eight bits of each character are discarded, thus this
   * method is inappropriate for completely representing Unicode characters.
   *
   * @param value The <code>String</code> to write to the stream
   *
   * @exception IOException If an error occurs
   */
  public final void writeBytes (String value) throws IOException
  {
    int len = value.length();
    for (int i = 0; i < len; ++i)
      writeByte (value.charAt(i));
  }

  /**
   * This method writes all the characters of a <code>String</code> to an
   * output stream as an array of <code>char</code>'s. Each character
   * is written using the method specified in the <code>writeChar</code>
   * method.
   *
   * @param value The <code>String</code> to write to the stream
   *
   * @exception IOException If an error occurs
   *
   * @see #writeChar(char)
   */
  public final void writeChars (String value) throws IOException
  {
    int len = value.length();
    for (int i = 0; i < len; ++i)
      writeChar (value.charAt(i));
  }

  /**
   * This method writes a Java <code>String</code> to the stream in a modified
   * UTF-8 format.  First, two bytes are written to the stream indicating the
   * number of bytes to follow.  Note that this is the number of bytes in the
   * encoded <code>String</code> not the <code>String</code> length.  Next
   * come the encoded characters.  Each character in the <code>String</code>
   * is encoded as either one, two or three bytes.  For characters in the
   * range of <code>\u0001</code> to <\u007F>, one byte is used.  The character
   * value goes into bits 0-7 and bit eight is 0.  For characters in the range
   * of <code>\u0080</code> to <code>\u007FF</code>, two bytes are used.  Bits
   * 6-10 of the character value are encoded bits 0-4 of the first byte, with
   * the high bytes having a value of "110".  Bits 0-5 of the character value
   * are stored in bits 0-5 of the second byte, with the high bits set to
   * "10".  This type of encoding is also done for the null character
   * <code>\u0000</code>.  This eliminates any C style NUL character values
   * in the output.  All remaining characters are stored as three bytes.
   * Bits 12-15 of the character value are stored in bits 0-3 of the first
   * byte.  The high bits of the first bytes are set to "1110".  Bits 6-11
   * of the character value are stored in bits 0-5 of the second byte.  The
   * high bits of the second byte are set to "10".  And bits 0-5 of the
   * character value are stored in bits 0-5 of byte three, with the high bits
   * of that byte set to "10".
   *
   * The value written can be read using the <code>readUTF</code>
   * method in <code>DataInput</code>.
   *
   * @param value The <code>String</code> to write to the output in UTF format
   *
   * @exception IOException If an error occurs
   *
   * @see DataInput#readUTF
   */
  public final synchronized void writeUTF(String value) throws IOException
  {
    int len = value.length();
    int sum = 0;

    for (int i = 0; i < len && sum <= 65535; ++i)
      {
	char c = value.charAt(i);
	if (c >= '\u0001' && c <= '\u007f')
	  sum += 1;
	else if (c == '\u0000' || (c >= '\u0080' && c <= '\u07ff'))
	  sum += 2;
	else
	  sum += 3;
      }

    if (sum > 65535)
      throw new UTFDataFormatException ();

    int pos = 0;
    byte[] buf = new byte[sum];

    for (int i = 0; i < len; ++i)
      {
	char c = value.charAt(i);
	if (c >= '\u0001' && c <= '\u007f')
          buf[pos++] = (byte) c;
	else if (c == '\u0000' || (c >= '\u0080' && c <= '\u07ff'))
	  {
	    buf[pos++] = (byte) (0xc0 | (0x1f & (c >> 6)));
	    buf[pos++] = (byte) (0x80 | (0x3f & c));
	  }
	else
	  {
	    // JSL says the first byte should be or'd with 0xc0, but
	    // that is a typo.  Unicode says 0xe0, and that is what is
	    // consistent with DataInputStream.
	    buf[pos++] = (byte) (0xe0 | (0x0f & (c >> 12)));
	    buf[pos++] = (byte) (0x80 | (0x3f & (c >> 6)));
	    buf[pos++] = (byte) (0x80 | (0x3f & c));
	  }
      }
    
    writeShort (sum);
    write(buf, 0, sum);
  }

} // class DataOutputStream