Class FileCodestreamWriter

  • All Implemented Interfaces:
    Markers

    public class FileCodestreamWriter
    extends CodestreamWriter
    implements Markers
    This class implements a CodestreamWriter for Java streams. The streams can be files or network connections, or any other resource that presents itself as a OutputStream. See the CodestreamWriter abstract class for more details on the implementation of the CodestreamWriter abstract class.

    Before any packet data is written to the bit stream (even in simulation mode) the complete header should be written to the HeaderEncoder object supplied to the constructor, following the procedure explained in the HeaderEncoder class. Otherwise incorrect estimates are given by getMaxAvailableBytes() for rate allocation.

    See Also:
    CodestreamWriter, HeaderEncoder
    • Field Detail

      • DEF_BUF_LEN

        public static int DEF_BUF_LEN
        The default buffer length, 1024 bytes
    • Constructor Detail

      • FileCodestreamWriter

        public FileCodestreamWriter​(File file,
                                    int mb)
                             throws IOException
        Opens the file 'file' for writing the bit stream, using the 'he' header encoder. The magic number is written to the bit stream. Normally, the header encoder must be empty (i.e. no data has been written to it yet). A BufferedOutputStream is used on top of the file to increase throughput, the length of the buffer is DEF_BUF_LEN.
        Parameters:
        file - The file where to write the bit stream
        mb - The maximum number of bytes that can be written to the bit stream.
        Throws:
        IOException - If an error occurs while trying to open the file for writing or while writing the magic number.
      • FileCodestreamWriter

        public FileCodestreamWriter​(String fname,
                                    int mb)
                             throws IOException
        Opens the file named 'fname' for writing the bit stream, using the 'he' header encoder. The magic number is written to the bit stream. Normally, the header encoder must be empty (i.e. no data has been written to it yet). A BufferedOutputStream is used on top of the file to increase throughput, the length of the buffer is DEF_BUF_LEN.
        Parameters:
        fname - The name of file where to write the bit stream
        mb - The maximum number of bytes that can be written to the bit stream.
        Throws:
        IOException - If an error occurs while trying to open the file for writing or while writing the magic number.
      • FileCodestreamWriter

        public FileCodestreamWriter​(OutputStream os,
                                    int mb)
                             throws IOException
        Uses the output stream 'os' for writing the bit stream, using the 'he' header encoder. The magic number is written to the bit stream. Normally, the header encoder must be empty (i.e. no data has been written to it yet). No BufferedOutputStream is used on top of the output stream 'os'.
        Parameters:
        os - The output stream where to write the bit stream.
        mb - The maximum number of bytes that can be written to the bit stream.
        Throws:
        IOException - If an error occurs while writing the magic number to the 'os' output stream.
    • Method Detail

      • getMaxAvailableBytes

        public final int getMaxAvailableBytes()
        Returns the number of bytes remaining available in the bit stream. This is the maximum allowed number of bytes minus the number of bytes that have already been written to the bit stream. If more bytes have been written to the bit stream than the maximum number of allowed bytes, then a negative value is returned.
        Specified by:
        getMaxAvailableBytes in class CodestreamWriter
        Returns:
        The number of bytes remaining available in the bit stream.
      • getLength

        public int getLength()
        Returns the current length of the entire bit stream.
        Specified by:
        getLength in class CodestreamWriter
        Returns:
        the current length of the bit stream
      • writePacketHead

        public int writePacketHead​(byte[] head,
                                   int hlen,
                                   boolean sim,
                                   boolean sop,
                                   boolean eph)
                            throws IOException
        Writes a packet head to the bit stream and returns the number of bytes used by this header. It returns the total number of bytes that the packet head takes in the bit stream. If in simulation mode then no data is written to the bit stream but the number of bytes is calculated. This can be used for iterative rate allocation.

        If the length of the data that is to be written to the bit stream is more than the space left (as returned by getMaxAvailableBytes()) only the data that does not exceed the allowed length is written, the rest is discarded. However the value returned by the method is the total length of the packet, as if all of it was written to the bit stream.

        If the bit stream header has not been commited yet and 'sim' is false, then the bit stream header is automatically commited (see commitBitstreamHeader() method) before writting the packet.

        Specified by:
        writePacketHead in class CodestreamWriter
        Parameters:
        head - The packet head data.
        hlen - The number of bytes in the packet head.
        sim - Simulation mode flag. If true nothing is written to the bit stream, but the number of bytes that would be written is returned.
        sop - Start of packet header marker flag. This flag indicates whether or not SOP markers should be written. If true, SOP markers should be written, if false, they should not.
        eph - End of Packet Header marker flag. This flag indicates whether or not EPH markers should be written. If true, EPH markers should be written, if false, they should not.
        Returns:
        The number of bytes spent by the packet head.
        Throws:
        IOException - If an I/O error occurs while writing to the output stream.
        See Also:
        commitBitstreamHeader(jj2000.j2k.codestream.writer.HeaderEncoder)
      • writePacketBody

        public int writePacketBody​(byte[] body,
                                   int blen,
                                   boolean sim,
                                   boolean roiInPkt,
                                   int roiLen)
                            throws IOException
        Writes a packet body to the bit stream and returns the number of bytes used by this body .If in simulation mode then no data is written to the bit stream but the number of bytes is calculated. This can be used for iterative rate allocation.

        If the length of the data that is to be written to the bit stream is more than the space left (as returned by getMaxAvailableBytes()) only the data that does not exceed the allowed length is written, the rest is discarded. However the value returned by the method is the total length of the packet body , as if all of it was written to the bit stream.

        Specified by:
        writePacketBody in class CodestreamWriter
        Parameters:
        body - The packet body data.
        blen - The number of bytes in the packet body.
        sim - Simulation mode flag. If true nothing is written to the bit stream, but the number of bytes that would be written is returned.
        roiInPkt - Whether or not this packet contains ROI information
        roiLen - Number of byte to read in packet body to get all the ROI information
        Returns:
        The number of bytes spent by the packet body.
        Throws:
        IOException - If an I/O error occurs while writing to the output stream.
        See Also:
        commitBitstreamHeader(jj2000.j2k.codestream.writer.HeaderEncoder)
      • close

        public void close()
                   throws IOException
        Writes the EOC marker and closes the underlying stream.
        Specified by:
        close in class CodestreamWriter
        Throws:
        IOException - If an error occurs while closing the underlying stream.
      • getOffLastROIPkt

        public int getOffLastROIPkt()
        Gives the offset of the end of last packet containing ROI information
        Specified by:
        getOffLastROIPkt in class CodestreamWriter
        Returns:
        End of last ROI packet
      • commitBitstreamHeader

        public void commitBitstreamHeader​(HeaderEncoder he)
                                   throws IOException
        Writes the header data in the codestream and actualize ndata with the header length. The header is either a MainHeaderEncoder or a TileHeaderEncoder.
        Specified by:
        commitBitstreamHeader in class CodestreamWriter
        Parameters:
        he - The current header encoder.
        Throws:
        IOException - If an I/O error occurs while writing the data.