org.freehep.util.io
Class ByteCountOutputStream

java.lang.Object
  java.io.OutputStream
      java.io.FilterOutputStream
          org.freehep.util.io.CompressableOutputStream
              org.freehep.util.io.BitOutputStream
                  org.freehep.util.io.ByteOrderOutputStream
                      org.freehep.util.io.ByteCountOutputStream

All Implemented Interfaces:

Closeable, DataOutput, Flushable, FinishableOutputStream

Direct Known Subclasses:

TaggedOutputStream

public class ByteCountOutputStream
extends ByteOrderOutputStream

Allows to write to some internal buffer and keep count of any set of stacked buffers written. When a pushBuffer is called, a new buffer is created. When a popBuffer is called, the number of bytes written to the popped buffer is returned. From this moment on one is writing again to the underlying buffer/outputstream. A header can be written and the header can be written. By calling append(), the previous buffer will be appended to the underlying one. This way one can write into a buffer, retrieve its length, create some header bytes and insert those in front of the just written buffer.

Version:

$Id: ByteCountOutputStream.java 8584 2006-08-10 23:06:37Z duns $

Author:

Mark Donszelmann, Ian Graham - added popBufferBytes() for use by CGMOutputStream

Field Summary

Fields inherited from class org.freehep.util.io.ByteOrderOutputStream

little, written

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

ByteCountOutputStream(OutputStream out, boolean littleEndian)
Create a Byte Count output stream from given stream

Method Summary

void	append() Inserts the bytes written as header and puts the write pointer at the end of the stream.
void	close() closes the stream, inserting any non-written header.
int	getBufferLength()
int	getLength()
int	popBuffer() returns the number of bytes written since the last pushBuffer call.
byte[]	popBufferBytes() Similar to pop buffer, but returns the actual byte[] buffer and then removes it from the bufferList so that subsequent appends will have no action.
void	pushBuffer() Pushes the buffer and strat writing to a new one.
void	write(int b)

Methods inherited from class org.freehep.util.io.ByteOrderOutputStream

size, writeAsciiZString, writeBoolean, writeByte, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFloat, writeInt, writeInt, writeLong, writeShort, writeShort, writeString, writeUnsignedByte, writeUnsignedByte, writeUnsignedInt, writeUnsignedInt, writeUnsignedShort, writeUnsignedShort, writeUTF, writeUTF

Methods inherited from class org.freehep.util.io.BitOutputStream

byteAlign, finish, flushByte, minBits, minBits, minBits, writeBitFlag, writeFBits, writeSBits, writeUBits

Methods inherited from class org.freehep.util.io.CompressableOutputStream

startCompressing, write

Methods inherited from class java.io.FilterOutputStream

flush, write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.io.DataOutput

write, write

Constructor Detail

ByteCountOutputStream

public ByteCountOutputStream(OutputStream out,
                             boolean littleEndian)

Create a Byte Count output stream from given stream

Parameters:

out - stream to write to

littleEndian - true if stream should be little endian

Method Detail

write

public void write(int b)
           throws IOException

Specified by:

write in interface DataOutput

Overrides:

write in class ByteOrderOutputStream

Throws:

IOException

pushBuffer

public void pushBuffer()
                throws IOException

Pushes the buffer and strat writing to a new one.

Throws:

IOException - if the write fails

popBuffer

public int popBuffer()
              throws IOException

returns the number of bytes written since the last pushBuffer call. It also puts the write pointer at the start of the buffer, to be able to "insert" a header. If no buffer was ever pushed, or the last one has been popped -1 is returned.

Returns:

number of bytes written or -1

Throws:

IOException - if the write fails

popBufferBytes

public byte[] popBufferBytes()
                      throws IOException

Similar to pop buffer, but returns the actual byte[] buffer and then removes it from the bufferList so that subsequent appends will have no action. When using this method, the caller is responsible for writing all buffered data as desired. The byte[] array will usually be larger than the actual content, so to determine the length of the actual data, you must call getBufferLength() before invoking this method.

Returns:

byte array of bytes that need to be written

Throws:

IOException - if write fails

getBufferLength

public int getBufferLength()

Returns:

valid number of bytes in the buffer

getLength

public int getLength()

Returns:

total number of bytes written

append

public void append()
            throws IOException

Inserts the bytes written as header and puts the write pointer at the end of the stream.

Throws:

IOException - if write fails

close

public void close()
           throws IOException

closes the stream, inserting any non-written header.

Specified by:

close in interface Closeable

Overrides:

close in class BitOutputStream

Throws:

IOException