Package net.sf.jazzlib

Class StreamManipulator

  • class StreamManipulator
extends java.lang.Object
    This class allows us to retrieve a specified amount of bits from the input buffer, as well as copy big byte blocks. It uses an int buffer to store up to 31 bits for direct manipulation. This guarantees that we can get at least 16 bits, but we only need at most 15, so this is all safe. There are some optimizations in this class, for example, you must never peek more then 8 bits more than needed, and you must first peek bits before you may drop them. This is not a general purpose class but optimized for the behaviour of the Inflater.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int copyBytes​(byte[] output, int offset, int length)  
      void dropBits​(int n)  
      int getAvailableBits()
      Gets the number of bits available in the bit buffer.
      int getAvailableBytes()
      Gets the number of bytes available.
      int getBits​(int n)
      Gets the next n bits and increases input pointer.
      boolean needsInput()  
      int peekBits​(int n)
      Get the next n bits but don't increase input pointer.
      void reset()  
      void setInput​(byte[] buf, int off, int len)  
      void skipToByteBoundary()
      Skips to the next byte boundary.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • window

        private byte[] window

      • window_start

        private int window_start

      • window_end

        private int window_end

      • buffer

        private int buffer

      • bits_in_buffer

        private int bits_in_buffer

    • Constructor Detail

      • StreamManipulator

        public StreamManipulator()

    • Method Detail

      • peekBits

        public final int peekBits​(int n)
        Get the next n bits but don't increase input pointer. n must be less or equal 16 and if you if this call succeeds, you must drop at least n-8 bits in the next call.
        Returns:
        the value of the bits, or -1 if not enough bits available.

      • dropBits

        public final void dropBits​(int n)

      • getBits

        public final int getBits​(int n)
        Gets the next n bits and increases input pointer. This is equivalent to peekBits followed by dropBits, except for correct error handling.
        Returns:
        the value of the bits, or -1 if not enough bits available.

      • getAvailableBits

        public final int getAvailableBits()
        Gets the number of bits available in the bit buffer. This must be only called when a previous peekBits() returned -1.
        Returns:
        the number of bits available.

      • getAvailableBytes

        public final int getAvailableBytes()
        Gets the number of bytes available.
        Returns:
        the number of bytes available.

      • skipToByteBoundary

        public void skipToByteBoundary()
        Skips to the next byte boundary.

      • needsInput

        public final boolean needsInput()

      • copyBytes

        public int copyBytes​(byte[] output,
                     int offset,
                     int length)

      • reset

        public void reset()

      • setInput

        public void setInput​(byte[] buf,
                     int off,
                     int len)