Packed64

java.lang.Object
- org.apache.lucene.util.packed.PackedInts.Reader
- - org.apache.lucene.util.packed.PackedInts.Mutable
  - - org.apache.lucene.util.packed.PackedInts.MutableImpl
    - - org.apache.lucene.util.packed.Packed64

All Implemented Interfaces:

Accountable
```
class Packed64
extends PackedInts.MutableImpl
```
Space optimized random access capable array of values with a fixed number of bits/value. Values are packed contiguously.
The implementation strives to perform as fast as possible under the constraint of contiguous bits, by avoiding expensive operations. This comes at the cost of code clarity.
Technical details: This implementation is a refinement of a non-branching version. The non-branching get and set methods meant that 2 or 4 atomics in the underlying array were always accessed, even for the cases where only 1 or 2 were needed. Even with caching, this had a detrimental effect on performance. Related to this issue, the old implementation used lookup tables for shifts and masks, which also proved to be a bit slower than calculating the shifts and masks on the fly. See https://issues.apache.org/jira/browse/LUCENE-4062 for details.

Field Summary

Fields
Modifier and Type	Field and Description
`(package private) static int`	`BLOCK_BITS`
`(package private) static int`	`BLOCK_SIZE`
`private long[]`	`blocks` Values are stores contiguously in the blocks array.
`private int`	`bpvMinusBlockSize` Optimization: Saves one lookup in `get(int)`.
`private long`	`maskRight` A right-aligned mask of width BitsPerValue used by `get(int)`.
`(package private) static int`	`MOD_MASK`

Fields inherited from class org.apache.lucene.util.packed.PackedInts.MutableImpl
bitsPerValue, valueCount

Constructor Summary

Constructors
Constructor and Description
`Packed64(int packedIntsVersion, DataInput in, int valueCount, int bitsPerValue)` Creates an array with content retrieved from the given DataInput.
`Packed64(int valueCount, int bitsPerValue)` Creates an array with the internal structures adjusted for the given limits and initialized to 0.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Sets all values to 0.
`void`	`fill(int fromIndex, int toIndex, long val)` Fill the mutable from `fromIndex` (inclusive) to `toIndex` (exclusive) with `val`.
`private static int`	`gcd(int a, int b)`
`long`	`get(int index)` Get the long at the given index.
`int`	`get(int index, long[] arr, int off, int len)` Bulk get: read at least one and at most `len` longs starting from `index` into `arr[off:off+len]` and return the actual number of values that have been read.
`long`	`ramBytesUsed()` Return the memory usage of this object in bytes.
`void`	`set(int index, long value)` Set the value at the given index in the array.
`int`	`set(int index, long[] arr, int off, int len)` Bulk set: set at least one and at most `len` longs starting at `off` in `arr` into this mutable, starting at `index`.
`java.lang.String`	`toString()`

Methods inherited from class org.apache.lucene.util.packed.PackedInts.MutableImpl
getBitsPerValue, size

Methods inherited from class org.apache.lucene.util.packed.PackedInts.Mutable
getFormat, save

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.lucene.util.Accountable
getChildResources

- Field Detail
  - BLOCK_SIZE
```
static final int BLOCK_SIZE
```
    See Also:
    
    Constant Field Values
  - BLOCK_BITS
```
static final int BLOCK_BITS
```
    See Also:
    
    Constant Field Values
  - MOD_MASK
```
static final int MOD_MASK
```
    See Also:
    
    Constant Field Values
  - blocks
```
private final long[] blocks
```
    Values are stores contiguously in the blocks array.
  - maskRight
```
private final long maskRight
```
    A right-aligned mask of width BitsPerValue used by get(int).
  - bpvMinusBlockSize
```
private final int bpvMinusBlockSize
```
    Optimization: Saves one lookup in get(int).
- Constructor Detail
  - Packed64
```
public Packed64(int valueCount,
                int bitsPerValue)
```
    Creates an array with the internal structures adjusted for the given limits and initialized to 0.
    
    Parameters:
    
    valueCount - the number of elements.
    
    bitsPerValue - the number of bits available for any given value.
  - Packed64
```
public Packed64(int packedIntsVersion,
                DataInput in,
                int valueCount,
                int bitsPerValue)
         throws java.io.IOException
```
    Creates an array with content retrieved from the given DataInput.
    
    Parameters:
    
    in - a DataInput, positioned at the start of Packed64-content.
    
    valueCount - the number of elements.
    
    bitsPerValue - the number of bits available for any given value.
    
    Throws:
    
    java.io.IOException - if the values for the backing array could not be retrieved.
- Method Detail
  - get
```
public long get(int index)
```
    Description copied from class: PackedInts.Reader
    
    Get the long at the given index. Behavior is undefined for out-of-range indices.
    
    Specified by:
    
    get in class PackedInts.Reader
    
    Parameters:
    
    index - the position of the value.
    
    Returns:
    
    the value at the given index.
  - get
```
public int get(int index,
               long[] arr,
               int off,
               int len)
```
    Description copied from class: PackedInts.Reader
    
    Bulk get: read at least one and at most len longs starting from index into arr[off:off+len] and return the actual number of values that have been read.
    
    Overrides:
    
    get in class PackedInts.Reader
  - set
```
public void set(int index,
                long value)
```
    Description copied from class: PackedInts.Mutable
    
    Set the value at the given index in the array.
    
    Specified by:
    
    set in class PackedInts.Mutable
    
    Parameters:
    
    index - where the value should be positioned.
    
    value - a value conforming to the constraints set by the array.
  - set
```
public int set(int index,
               long[] arr,
               int off,
               int len)
```
    Description copied from class: PackedInts.Mutable
    
    Bulk set: set at least one and at most len longs starting at off in arr into this mutable, starting at index. Returns the actual number of values that have been set.
    
    Overrides:
    
    set in class PackedInts.Mutable
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class PackedInts.MutableImpl
  - ramBytesUsed
```
public long ramBytesUsed()
```
    Description copied from interface: Accountable
    
    Return the memory usage of this object in bytes. Negative values are illegal.
  - fill
```
public void fill(int fromIndex,
                 int toIndex,
                 long val)
```
    Description copied from class: PackedInts.Mutable
    
    Fill the mutable from fromIndex (inclusive) to toIndex (exclusive) with val.
    
    Overrides:
    
    fill in class PackedInts.Mutable
  - gcd
```
private static int gcd(int a,
                       int b)
```
  - clear
```
public void clear()
```
    Description copied from class: PackedInts.Mutable
    
    Sets all values to 0.
    
    Overrides:
    
    clear in class PackedInts.Mutable

Class Packed64

Field Summary

Fields inherited from class org.apache.lucene.util.packed.PackedInts.MutableImpl

Constructor Summary

Method Summary

Methods inherited from class org.apache.lucene.util.packed.PackedInts.MutableImpl

Methods inherited from class org.apache.lucene.util.packed.PackedInts.Mutable

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.lucene.util.Accountable

Field Detail

BLOCK_SIZE

BLOCK_BITS

MOD_MASK

blocks

maskRight

bpvMinusBlockSize

Constructor Detail

Packed64

Packed64

Method Detail

get

get

set

set

toString

ramBytesUsed

fill

gcd

clear