Package org.terrier.compression.bit

Class BitInBase

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, BitIn
    Direct Known Subclasses:
    BitFileBuffered.BitInBuffered, BitInputStream
    public abstract class BitInBase
extends java.lang.Object
implements BitIn
    Base class for various BitIn implementations
    Since:
    3.6
    Author:
    Craig Macdonald

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected int bitOffset
      bit offset in this byte, and in the larger file
      protected byte byteRead
      current byte
      protected long offset
      offset in the larger file

    • Constructor Summary

      Constructors 
      Constructor Description
      BitInBase()  

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      void align()
      Aligns the stream to the next byte
      byte getBitOffset()
      Returns the bit offset in the last byte.
      long getByteOffset()
      Returns the byte offset of the stream.
      protected abstract void incrByte()
      Move forward one byte.
      protected abstract void incrByte​(int i)
      Move forward i bytes.
      int readBinary​(int len)
      Reads a binary integer from the already read buffer.
      int readDelta()
      Reads a delta encoded integer from the underlying stream
      int readGamma()
      Reads a gamma encoded integer from the underlying stream
      int readGolomb​(int b)
      Reads a Golomb encoded integer
      protected void readIn()
      Reads a new byte from the InputStream if we have finished with the current one.
      void readInterpolativeCoding​(int[] data, int localoffset, int len, int lo, int hi)
      Reads a sequence of numbers from the stream interpolative coded.
      int readMinimalBinary​(int b)
      Reads a binary encoded integer, given an upper bound
      int readMinimalBinaryZero​(int b)
      Reads a minimal binary encoded number, when the upper bound can b zero.
      int readSkewedGolomb​(int b)
      Reads a skewed-golomb encoded integer from the underlying stream Consider a bucket-vector v = <0, 2b, 4b, ...
      int readUnary()
      Reads a unary encoded integer from the underlying stream
      void skipBits​(int len)
      Skip a number of bits in the current input stream

      • Methods inherited from class java.lang.Object

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

      • Methods inherited from interface org.terrier.compression.bit.BitIn

        skipBytes

      • Methods inherited from interface java.io.Closeable

        close

    • Field Detail

      • bitOffset

        protected int bitOffset
        bit offset in this byte, and in the larger file

      • offset

        protected long offset
        offset in the larger file

      • byteRead

        protected byte byteRead
        current byte

    • Constructor Detail

      • BitInBase

        public BitInBase()

    • Method Detail

      • getByteOffset

        public long getByteOffset()
        Returns the byte offset of the stream. It corresponds to the position of the byte in which the next bit will be written. Use only when writting
        Specified by:
        getByteOffset in interface BitIn
        Returns:
        the byte offset in the stream.

      • getBitOffset

        public byte getBitOffset()
        Returns the bit offset in the last byte. It corresponds to the position in which the next bit will be written. Use only when writting.
        Specified by:
        getBitOffset in interface BitIn
        Returns:
        the bit offset in the stream.

      • readUnary

        public int readUnary()
              throws java.io.IOException
        Reads a unary encoded integer from the underlying stream
        Specified by:
        readUnary in interface BitIn
        Returns:
        the number read
        Throws:
        java.io.IOException - if an I/O error occurs

      • readBinary

        public int readBinary​(int len)
               throws java.io.IOException
        Reads a binary integer from the already read buffer.
        Specified by:
        readBinary in interface BitIn
        Parameters:
        len - the number of binary bits to read
        Returns:
        the decoded integer
        Throws:
        java.io.IOException - if an I/O error occurs

      • readDelta

        public int readDelta()
              throws java.io.IOException
        Reads a delta encoded integer from the underlying stream
        Specified by:
        readDelta in interface BitIn
        Returns:
        the number read
        Throws:
        java.io.IOException - if an I/O error occurs

      • readGamma

        public int readGamma()
              throws java.io.IOException
        Reads a gamma encoded integer from the underlying stream
        Specified by:
        readGamma in interface BitIn
        Returns:
        the number read
        Throws:
        java.io.IOException - if an I/O error occurs

      • readSkewedGolomb

        public int readSkewedGolomb​(int b)
                     throws java.io.IOException
        Reads a skewed-golomb encoded integer from the underlying stream Consider a bucket-vector v = <0, 2b, 4b, ... , 2^i b, ...> The sum of the elements in the vector goes b, 3b, 7b, 2^(i-1)*b
        Specified by:
        readSkewedGolomb in interface BitIn
        Returns:
        the number read
        Throws:
        java.io.IOException - if an I/O error occurs

      • readGolomb

        public int readGolomb​(int b)
               throws java.io.IOException
        Reads a Golomb encoded integer
        Specified by:
        readGolomb in interface BitIn
        Parameters:
        b - the golomb modulus
        Returns:
        the int read
        Throws:
        java.io.IOException - if and I/O error occurs

      • readMinimalBinary

        public int readMinimalBinary​(int b)
                      throws java.io.IOException
        Reads a binary encoded integer, given an upper bound
        Specified by:
        readMinimalBinary in interface BitIn
        Parameters:
        b - the upper bound
        Returns:
        the int read
        Throws:
        java.io.IOException - if an I/O error occurs

      • readMinimalBinaryZero

        public int readMinimalBinaryZero​(int b)
                          throws java.io.IOException
        Reads a minimal binary encoded number, when the upper bound can b zero. Used to interpolative code
        Specified by:
        readMinimalBinaryZero in interface BitIn
        Parameters:
        b - the upper bound
        Returns:
        the int read
        Throws:
        java.io.IOException - if an I/O error occurs

      • readInterpolativeCoding

        public void readInterpolativeCoding​(int[] data,
                                    int localoffset,
                                    int len,
                                    int lo,
                                    int hi)
                             throws java.io.IOException
        Reads a sequence of numbers from the stream interpolative coded.
        Specified by:
        readInterpolativeCoding in interface BitIn
        Parameters:
        data - the result vector
        localoffset - offset where to write in the vector
        len - the number of integers to decode.
        lo - a lower bound (the same one passed to writeInterpolativeCoding)
        hi - an upper bound (the same one passed to writeInterpolativeCoding)
        Throws:
        java.io.IOException - if an I/O error occurs

      • skipBits

        public void skipBits​(int len)
              throws java.io.IOException
        Skip a number of bits in the current input stream
        Specified by:
        skipBits in interface BitIn
        Parameters:
        len - The number of bits to skip
        Throws:
        java.io.IOException - if an I/O error occurs

      • align

        public void align()
           throws java.io.IOException
        Aligns the stream to the next byte
        Specified by:
        align in interface BitIn
        Throws:
        java.io.IOException - if an I/O error occurs

      • incrByte

        protected abstract void incrByte()
                          throws java.io.IOException
        Move forward one byte. The newly read byte should appear in the byteRead variable.
        Throws:
        java.io.IOException

      • incrByte

        protected abstract void incrByte​(int i)
                          throws java.io.IOException
        Move forward i bytes. The newly read byte should appear in byteRead variable.
        Throws:
        java.io.IOException

      • readIn

        protected void readIn()
               throws java.io.IOException
        Reads a new byte from the InputStream if we have finished with the current one.
        Throws:
        java.io.IOException