Package org.eclipse.mat.collect

Class ArrayIntCompressed

java.lang.Object
org.eclipse.mat.collect.ArrayIntCompressed
public class ArrayIntCompressed extends Object
This class compresses fixed-size int[] in a very fast and memory efficient manner if many leading and/or trailing bits of the stored ints are not used commonly. The internal data is never copied during the process of retrieving or reconstructing objects of this class and allows for fast I/O writing and reading of the underlying byte[]. Furthermore almost no additional data is used beside the underlying byte[]. Thereby the memory consumption of this data structure is kept at a minimum to build efficient int[] caches.

  • Constructor Summary

    Constructors
    Constructor
    Description
    ArrayIntCompressed(byte[] bytes)
    Create IntArrayCompressed from bytes formerly got from toByteArray().
    ArrayIntCompressed(int[] ints)
    Create IntArrayCompressed from ints representing the data to be stored in compressed form.
    ArrayIntCompressed(int[] ints, int offset, int length)
    Create IntArrayCompressed from ints representing the data to be stored in compressed form (from offset to offset+length).
    ArrayIntCompressed(int size, int leadingClearBits, int trailingClearBits)
    Create IntArrayCompressed from number of ints to be stored, the number of leading and trailing clear bits.

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    get(int index)
    Get value from the given index.
    void
    set(int index, int value)
    Set value at the given index.
    byte[]
    toByteArray()
    Get bytes representing the internal data structure with which an IntArrayCompressed can be reconstructed.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • ArrayIntCompressed

      public ArrayIntCompressed(byte[] bytes)
      Create IntArrayCompressed from bytes formerly got from toByteArray().
      Parameters:
      bytes - bytes formerly got from toByteArray()

    • ArrayIntCompressed

      public ArrayIntCompressed(int size, int leadingClearBits, int trailingClearBits)
      Create IntArrayCompressed from number of ints to be stored, the number of leading and trailing clear bits. Everything else is stored in the internal data structure.
      Parameters:
      size - number of ints to be stored
      leadingClearBits - number of leading clear bits
      trailingClearBits - number of trailing clear bits

    • ArrayIntCompressed

      public ArrayIntCompressed(int[] ints)
      Create IntArrayCompressed from ints representing the data to be stored in compressed form.
      Parameters:
      ints - ints representing the data to be stored in compressed form

    • ArrayIntCompressed

      public ArrayIntCompressed(int[] ints, int offset, int length)
      Create IntArrayCompressed from ints representing the data to be stored in compressed form (from offset to offset+length).
      Parameters:
      ints - ints representing the data to be stored in compressed form
      offset - offset from which on to compress the ints
      length - number of ints to compress from the given array

  • Method Details

    • set

      public void set(int index, int value)
      Set value at the given index.
      Parameters:
      index - index at which the value should be set
      value - value to be set at the given index

    • get

      public int get(int index)
      Get value from the given index.
      Parameters:
      index - index at which the value should be set
      Returns:
      value found at the given index

    • toByteArray

      public byte[] toByteArray()
      Get bytes representing the internal data structure with which an IntArrayCompressed can be reconstructed.
      Returns:
      bytes representing the internal data structure with which an IntArrayCompressed can be reconstructed