org.eclipse.mat.collect
Class ArrayLongCompressed

java.lang.Object
  extended by org.eclipse.mat.collect.ArrayLongCompressed

public class ArrayLongCompressed
extends java.lang.Object

This class compresses fixed-size long[] in a very fast and memory efficient manner if many leading and/or trailing bits of the stored longs 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 alomst no additinal data is used beside the underlying byte[]. Thereby the memory consumption of this data structure is kept at a minmum to build efficient long[] caches.


Constructor Summary
ArrayLongCompressed(byte[] bytes)
          Create LongArrayCompressed from bytes formerly got from toByteArray().
ArrayLongCompressed(int size, int leadingClearBits, int trailingClearBits)
          Create LongArrayCompressed from number of longs to be stored, the number of leading and trailing clear bits.
ArrayLongCompressed(long[] longs)
          Create LongArrayCompressed from longs representing the data to be stored in compressed form.
ArrayLongCompressed(long[] longs, int offset, int length)
          Create LongArrayCompressed from longs representing the data to be stored in compressed form (from offset to offset+length).
 
Method Summary
 long get(int index)
          Get value from the given index.
 void set(int index, long value)
          Set value at the given index.
 byte[] toByteArray()
          Get bytes representing the internal data structure with which an LongArrayCompressed can be reconstructed.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ArrayLongCompressed

public ArrayLongCompressed(byte[] bytes)
Create LongArrayCompressed from bytes formerly got from toByteArray().

Parameters:
bytes - bytes formerly got from toByteArray()

ArrayLongCompressed

public ArrayLongCompressed(int size,
                           int leadingClearBits,
                           int trailingClearBits)
Create LongArrayCompressed from number of longs to be stored, the number of leading and trailing clear bits. Everything else is stored in the internal data structure.

Parameters:
size - number of longs to be stored
leadingClearBits - number of leading clear bits
trailingClearBits - number of trailing clear bits

ArrayLongCompressed

public ArrayLongCompressed(long[] longs)
Create LongArrayCompressed from longs representing the data to be stored in compressed form.

Parameters:
longs - longs representing the data to be stored in compressed form

ArrayLongCompressed

public ArrayLongCompressed(long[] longs,
                           int offset,
                           int length)
Create LongArrayCompressed from longs representing the data to be stored in compressed form (from offset to offset+length).

Parameters:
longs - longs representing the data to be stored in compressed form
offset - offset from which on to compress the longs
length - number of longs to compress from the given array
Method Detail

set

public void set(int index,
                long 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 long 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 LongArrayCompressed can be reconstructed.

Returns:
bytes representing the internal data structure with which an LongArrayCompressed can be reconstructed