Package org.eclipse.mat.collect
Class ArrayLongCompressed
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- org.eclipse.mat.collect.ArrayLongCompressed
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public class ArrayLongCompressed extends 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.
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Constructor Summary
Constructors Constructor Description ArrayLongCompressed(byte[] bytes)CreateLongArrayCompressedfrom bytes formerly got fromtoByteArray().ArrayLongCompressed(int size, int leadingClearBits, int trailingClearBits)CreateLongArrayCompressedfrom number of longs to be stored, the number of leading and trailing clear bits.ArrayLongCompressed(long[] longs)CreateLongArrayCompressedfrom longs representing the data to be stored in compressed form.ArrayLongCompressed(long[] longs, int offset, int length)CreateLongArrayCompressedfrom longs representing the data to be stored in compressed form (from offset to offset+length).
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description longget(int index)Get value from the given index.voidset(int index, long value)Set value at the given index.byte[]toByteArray()Get bytes representing the internal data structure with which anLongArrayCompressedcan be reconstructed.
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Constructor Detail
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ArrayLongCompressed
public ArrayLongCompressed(byte[] bytes)
CreateLongArrayCompressedfrom bytes formerly got fromtoByteArray().- Parameters:
bytes- bytes formerly got fromtoByteArray()
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ArrayLongCompressed
public ArrayLongCompressed(int size, int leadingClearBits, int trailingClearBits)CreateLongArrayCompressedfrom 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 storedleadingClearBits- number of leading clear bitstrailingClearBits- number of trailing clear bits
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ArrayLongCompressed
public ArrayLongCompressed(long[] longs)
CreateLongArrayCompressedfrom longs representing the data to be stored in compressed form.- Parameters:
longs- longs representing the data to be stored in compressed form
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ArrayLongCompressed
public ArrayLongCompressed(long[] longs, int offset, int length)CreateLongArrayCompressedfrom 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 formoffset- offset from which on to compress the longslength- number of longs to compress from the given array
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Method Detail
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set
public void set(int index, long value)Set value at the given index.- Parameters:
index- index at which the value should be setvalue- value to be set at the given index
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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
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toByteArray
public byte[] toByteArray()
Get bytes representing the internal data structure with which anLongArrayCompressedcan be reconstructed.- Returns:
- bytes representing the internal data structure with which an
LongArrayCompressedcan be reconstructed
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