Module kala.compress.compressors.pack200
Package kala.compress.harmony.unpack200

Class Segment

  • public class Segment
extends java.lang.Object
    A Pack200 archive consists of one or more segments. Each segment is stand-alone, in the sense that every segment has the magic number header; thus, every segment is also a valid archive. However, it is possible to combine (non-GZipped) archives into a single large archive by concatenation alone. Thus, all the hard work in unpacking an archive falls to understanding a segment. The first component of a segment is the header; this contains (amongst other things) the expected counts of constant pool entries, which in turn defines how many values need to be read from the stream. Because values are variable width (see Codec), it is not possible to calculate the start of the next segment, although one of the header values does hint at the size of the segment if non-zero, which can be used for buffering purposes. Note that this does not perform any buffering of the input stream; each value will be read on a byte-by-byte basis. It does not perform GZip decompression automatically; both of these are expected to be done by the caller if the stream has the magic header for GZip streams (GZIPInputStream.GZIP_MAGIC). In any case, if GZip decompression is being performed the input stream will be buffered at a higher level, and thus this can read on a byte-oriented basis.

    • Field Detail

      • overrideDeflateHint

        private boolean overrideDeflateHint

      • deflateHint

        private boolean deflateHint

      • doPreRead

        private boolean doPreRead

      • logLevel

        private int logLevel

      • logStream

        private java.io.PrintWriter logStream

      • classFilesContents

        private byte[][] classFilesContents

      • fileDeflate

        private boolean[] fileDeflate

      • fileIsClass

        private boolean[] fileIsClass

      • internalBuffer

        private java.io.InputStream internalBuffer

    • Constructor Detail

      • Segment

        public Segment()

    • Method Detail

      • buildClassFile

        private ClassFile buildClassFile​(int classNum)

      • computeIcStored

        private java.util.List<IcTuple> computeIcStored​(IcTuple[] icLocal,
                                                IcTuple[] icRelevant)
        Given an ic_local and an ic_relevant, use them to calculate what should be added as ic_stored.
        Parameters:
        icLocal - IcTuple[] array of local transmitted tuples
        icRelevant - IcTuple[] array of relevant tuples
        Returns:
        List of tuples to be stored. If ic_local is null or empty, the values returned may not be correct. The caller will have to determine if this is the case.

      • getClassBands

        protected ClassBands getClassBands()

      • getCpBands

        protected CpBands getCpBands()

      • getIcBands

        protected IcBands getIcBands()

      • log

        public void log​(int logLevel,
                java.lang.String message)

      • overrideDeflateHint

        public void overrideDeflateHint​(boolean deflateHint)
        Override the archive's deflate hint with the given boolean
        Parameters:
        deflateHint - the deflate hint to use

      • parseSegment

        private void parseSegment()
                   throws java.io.IOException,
                          Pack200Exception
        This performs the actual work of parsing against a non-static instance of Segment. This method is intended to run concurrently for multiple segments.
        Throws:
        java.io.IOException - if a problem occurs during reading from the underlying stream
        Pack200Exception - if a problem occurs with an unexpected value or unsupported codec

      • readSegment

        private void readSegment​(java.io.InputStream in)
                  throws java.io.IOException,
                         Pack200Exception
        This performs reading the data from the stream into non-static instance of Segment. After the completion of this method stream can be freed.
        Parameters:
        in - the input stream to read from
        Throws:
        java.io.IOException - if a problem occurs during reading from the underlying stream
        Pack200Exception - if a problem occurs with an unexpected value or unsupported codec

      • setLogLevel

        public void setLogLevel​(int logLevel)

      • setLogStream

        public void setLogStream​(java.io.OutputStream logStream)

      • setPreRead

        public void setPreRead​(boolean value)

      • unpack

        public void unpack​(java.io.InputStream inputStream,
                   java.util.jar.JarOutputStream out)
            throws java.io.IOException,
                   Pack200Exception
        Unpacks a packed stream (either .pack. or .pack.gz) into a corresponding JarOuputStream.
        Parameters:
        inputStream - a packed input stream, preferably a BoundedInputStream.
        out - output stream.
        Throws:
        Pack200Exception - if there is a problem unpacking
        java.io.IOException - if there is a problem with I/O during unpacking

      • unpackWrite

        void unpackWrite​(java.util.jar.JarOutputStream out)
          throws java.io.IOException
        Throws:
        java.io.IOException

      • writeJar

        public void writeJar​(java.util.jar.JarOutputStream out)
              throws java.io.IOException
        Writes the segment to an output stream. The output stream should be pre-buffered for efficiency. Also takes the same input stream for reading, since the file bits may not be loaded and thus just copied from one stream to another. Doesn't close the output stream when finished, in case there are more entries (e.g. further segments) to be written.
        Parameters:
        out - the JarOutputStream to write data to
        Throws:
        java.io.IOException - if an error occurs while reading or writing to the streams