Module me.lemire.integercompression
Package me.lemire.integercompression.differential

Class IntegratedVariableByte

java.lang.Object
me.lemire.integercompression.differential.IntegratedVariableByte
All Implemented Interfaces:
ByteIntegerCODEC, IntegratedByteIntegerCODEC, IntegratedIntegerCODEC, SkippableIntegratedIntegerCODEC, IntegerCODEC
public class IntegratedVariableByte extends Object implements IntegratedIntegerCODEC, IntegratedByteIntegerCODEC, SkippableIntegratedIntegerCODEC
Implementation of variable-byte with differential coding. For best performance, use it using the IntegratedByteIntegerCODEC interface. You should only use this scheme on sorted arrays. Use VariableByte if you have unsorted arrays.
Author:
Daniel Lemire

  • Constructor Details

    • IntegratedVariableByte

      public IntegratedVariableByte()

  • Method Details

    • compress

      public void compress(int[] in, IntWrapper inpos, int inlength, int[] out, IntWrapper outpos)
      Description copied from interface: IntegerCODEC
      Compress data from an array to another array. Both inpos and outpos are modified to represent how much data was read and written to. If 12 ints (inlength = 12) are compressed to 3 ints, then inpos will be incremented by 12 while outpos will be incremented by 3. We use IntWrapper to pass the values by reference.
      Specified by:
      compress in interface IntegerCODEC
      Parameters:
      in - input array
      inpos - where to start reading in the array
      inlength - how many integers to compress
      out - output array
      outpos - where to write in the output array

    • compress

      public void compress(int[] in, IntWrapper inpos, int inlength, byte[] out, IntWrapper outpos)
      Description copied from interface: ByteIntegerCODEC
      Compress data from an array to another array. Both inpos and outpos are modified to represent how much data was read and written to. If 12 ints (inlength = 12) are compressed to 3 bytes, then inpos will be incremented by 12 while outpos will be incremented by 3. We use IntWrapper to pass the values by reference.
      Specified by:
      compress in interface ByteIntegerCODEC
      Parameters:
      in - input array
      inpos - location in the input array
      inlength - how many integers to compress
      out - output array
      outpos - where to write in the output array

    • uncompress

      public void uncompress(int[] in, IntWrapper inpos, int inlength, int[] out, IntWrapper outpos)
      Description copied from interface: IntegerCODEC
      Uncompress data from an array to another array. Both inpos and outpos parameters are modified to indicate new positions after read/write.
      Specified by:
      uncompress in interface IntegerCODEC
      Parameters:
      in - array containing data in compressed form
      inpos - where to start reading in the array
      inlength - length of the compressed data (ignored by some schemes)
      out - array where to write the compressed output
      outpos - where to start writing the uncompressed output in out

    • uncompress

      public void uncompress(byte[] in, IntWrapper inpos, int inlength, int[] out, IntWrapper outpos)
      Description copied from interface: ByteIntegerCODEC
      Uncompress data from an array to another array. Both inpos and outpos parameters are modified to indicate new positions after read/write.
      Specified by:
      uncompress in interface ByteIntegerCODEC
      Parameters:
      in - array containing data in compressed form
      inpos - where to start reading in the array
      inlength - length of the compressed data (ignored by some schemes)
      out - array where to write the compressed output
      outpos - where to write the compressed output in out

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • headlessCompress

      public void headlessCompress(int[] in, IntWrapper inpos, int inlength, int[] out, IntWrapper outpos, IntWrapper initvalue)
      Description copied from interface: SkippableIntegratedIntegerCODEC
      Compress data from an array to another array. Both inpos and outpos are modified to represent how much data was read and written to if 12 ints (inlength = 12) are compressed to 3 ints, then inpos will be incremented by 12 while outpos will be incremented by 3 we use IntWrapper to pass the values by reference.
      Specified by:
      headlessCompress in interface SkippableIntegratedIntegerCODEC
      Parameters:
      in - input array
      inpos - location in the input array
      inlength - how many integers to compress
      out - output array
      outpos - where to write in the output array
      initvalue - initial value for the purpose of differential coding, the value is automatically updated

    • headlessUncompress

      public void headlessUncompress(int[] in, IntWrapper inpos, int inlength, int[] out, IntWrapper outpos, int num, IntWrapper initvalue)
      Description copied from interface: SkippableIntegratedIntegerCODEC
      Uncompress data from an array to another array. Both inpos and outpos parameters are modified to indicate new positions after read/write.
      Specified by:
      headlessUncompress in interface SkippableIntegratedIntegerCODEC
      Parameters:
      in - array containing data in compressed form
      inpos - where to start reading in the array
      inlength - length of the compressed data (ignored by some schemes)
      out - array where to write the compressed output
      outpos - where to write the compressed output in out
      num - number of integers we want to decode, the actual number of integers decoded can be less
      initvalue - initial value for the purpose of differential coding, the value is automatically updated

    • maxHeadlessCompressedLength

      public int maxHeadlessCompressedLength(IntWrapper compressedPositions, int inlength)
      Description copied from interface: SkippableIntegratedIntegerCODEC
      Compute the maximum number of integers that might be required to store the compressed form of a given input array segment, without headers.

      This is useful to pre-allocate the output buffer before calling SkippableIntegratedIntegerCODEC.headlessCompress(int[], IntWrapper, int, int[], IntWrapper, IntWrapper).

      Specified by:
      maxHeadlessCompressedLength in interface SkippableIntegratedIntegerCODEC
      Parameters:
      compressedPositions - since not all schemes compress every input integer, this parameter returns how many input integers will actually be compressed. This is useful when composing multiple schemes.
      inlength - number of integers to be compressed
      Returns:
      the maximum number of integers needed in the output array

    • makeBuffer

      protected ByteBuffer makeBuffer(int sizeInBytes)
      Creates a new buffer of the requested size. In case you need a different way to allocate buffers, you can override this method with a custom behavior. The default implementation allocates a new Java direct ByteBuffer on each invocation.