it.unimi.dsi.fastutil.ints

Class IntBigArrayBigList

java.lang.Object

java.util.AbstractCollection<Integer>

it.unimi.dsi.fastutil.ints.AbstractIntCollection

it.unimi.dsi.fastutil.ints.AbstractIntBigList

it.unimi.dsi.fastutil.ints.IntBigArrayBigList

All Implemented Interfaces:

BigList<Integer>, IntBigList, IntCollection, IntIterable, IntStack, Size64, Stack<Integer>, Serializable, Cloneable, Comparable<BigList<? extends Integer>>, Iterable<Integer>, Collection<Integer>, RandomAccess

public class IntBigArrayBigList
extends AbstractIntBigList
implements RandomAccess, Cloneable, Serializable

A type-specific big list based on a big array; provides some additional methods that use polymorphism to avoid (un)boxing.

This class implements a lightweight, fast, open, optimized, reuse-oriented version of big-array-based big lists. Instances of this class represent a big list with a big array that is enlarged as needed when new entries are created (by dividing the current length by the golden ratio), but is never made smaller (even on a clear()). A family of trimming methods lets you control the size of the backing big array; this is particularly useful if you reuse instances of this class. Range checks are equivalent to those of java.util's classes, but they are delayed as much as possible. The backing big array is exposed by the elements() method.

This class implements the bulk methods removeElements(), addElements() and getElements() using high-performance system calls (e.g., System.arraycopy() instead of expensive loops.

See Also:

ArrayList, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.ints.AbstractIntBigList

AbstractIntBigList.IntSubList

Field Summary

Fields

Modifier and Type	Field and Description
protected int[][]	a The backing big array.
static int	DEFAULT_INITIAL_CAPACITY The initial default capacity of a big-array big list.
protected static long	ONEOVERPHI The inverse of the golden ratio times 216.
static long	serialVersionUID
protected long	size The current actual size of the big list (never greater than the backing-array length).

Constructor Summary

Constructors

Modifier	Constructor and Description
	IntBigArrayBigList() Creates a new big-array big list with DEFAULT_INITIAL_CAPACITY capacity.
	IntBigArrayBigList(int[][] a) Creates a new big-array big list and fills it with the elements of a given big array.
protected	IntBigArrayBigList(int[][] a, boolean dummy) Creates a new big-array big list using a given array.
	IntBigArrayBigList(int[][] a, long offset, long length) Creates a new big-array big list and fills it with the elements of a given big array.
	IntBigArrayBigList(IntBigList l) Creates a new big-array big list and fills it with a given type-specific list.
	IntBigArrayBigList(IntCollection c) Creates a new big-array big list and fills it with a given type-specific collection.
	IntBigArrayBigList(IntIterator i) Creates a new big-array big list and fills it with the elements returned by a type-specific iterator..
	IntBigArrayBigList(Iterator<? extends Integer> i) Creates a new big-array big list and fills it with the elements returned by an iterator..
	IntBigArrayBigList(long capacity) Creates a new big-array big list with given capacity.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(int k)
void	add(long index, int k)
void	addElements(int index, int[][] a, long offset, long length) Adds elements to this type-specific list using optimized system calls.
void	clear()
IntBigArrayBigList	clone()
int	compareTo(IntBigArrayBigList l) Compares this big list to another big list.
int[][]	elements() Returns the backing big array of this big list.
void	ensureCapacity(long capacity) Ensures that this big-array big list can contain the given number of entries without resizing.
boolean	equals(IntBigArrayBigList l) Compares this type-specific big-array list to another one.
void	getElements(int from, int[][] a, long offset, long length) Copies element of this type-specific list into the given big array using optimized system calls.
int	getInt(long index)
long	indexOf(int k)
boolean	isEmpty() Checks whether the stack is empty.
long	lastIndexOf(int k)
IntBigListIterator	listIterator(int index)
boolean	rem(int k) Note that this method should be called remove(), but the clash with the similarly named index-based method in the List interface forces us to use a distinguished name.
void	removeElements(int from, int to) Removes elements of this type-specific list using optimized system calls.
int	removeInt(long index)
int	set(long index, int k)
void	size(long size) Sets the size of this big list.
long	size64() Returns the size of this data structure as a long.
void	trim() Trims this big-array big list so that the capacity is equal to the size.
void	trim(long n) Trims the backing big array if it is too large.
static IntBigArrayBigList	wrap(int[][] a) Wraps a given big array into a big-array big list.
static IntBigArrayBigList	wrap(int[][] a, long length) Wraps a given big array into a big-array list of given size.

Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntBigList

add, addAll, addAll, addAll, addAll, addAll, addAll, addAll, addElements, addElements, compareTo, contains, ensureIndex, ensureRestrictedIndex, equals, get, getElements, getInt, hashCode, indexOf, iterator, lastIndexOf, listIterator, listIterator, peek, peekInt, pop, popInt, push, push, remove, remove, removeElements, removeInt, set, set, size, size, subList, top, topInt, toString

Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractIntCollection

add, contains, containsAll, containsAll, intIterator, rem, remove, removeAll, removeAll, retainAll, retainAll, toArray, toArray, toArray, toIntArray, toIntArray

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface it.unimi.dsi.fastutil.ints.IntCollection

containsAll, intIterator, removeAll, retainAll, toArray, toArray, toIntArray, toIntArray

Methods inherited from interface java.util.Collection

add, contains, containsAll, remove, removeAll, retainAll, toArray

Field Detail

serialVersionUID

public static final long serialVersionUID

See Also:

Constant Field Values

DEFAULT_INITIAL_CAPACITY

public static final int DEFAULT_INITIAL_CAPACITY

The initial default capacity of a big-array big list.

See Also:

Constant Field Values

ONEOVERPHI

protected static final long ONEOVERPHI

The inverse of the golden ratio times 2¹⁶.

See Also:

Constant Field Values

a

protected transient int[][] a

The backing big array.

size

protected long size

The current actual size of the big list (never greater than the backing-array length).

Constructor Detail

IntBigArrayBigList

protected IntBigArrayBigList(int[][] a,
                  boolean dummy)

Creates a new big-array big list using a given array.

This constructor is only meant to be used by the wrapping methods.

Parameters:

a - the big array that will be used to back this big-array big list.

IntBigArrayBigList

public IntBigArrayBigList(long capacity)

Creates a new big-array big list with given capacity.

Parameters:

capacity - the initial capacity of the array list (may be 0).

IntBigArrayBigList

public IntBigArrayBigList()

Creates a new big-array big list with DEFAULT_INITIAL_CAPACITY capacity.

IntBigArrayBigList

public IntBigArrayBigList(IntCollection c)

Creates a new big-array big list and fills it with a given type-specific collection.

Parameters:

c - a type-specific collection that will be used to fill the array list.

IntBigArrayBigList

public IntBigArrayBigList(IntBigList l)

Creates a new big-array big list and fills it with a given type-specific list.

Parameters:

l - a type-specific list that will be used to fill the array list.

IntBigArrayBigList

public IntBigArrayBigList(int[][] a)

Creates a new big-array big list and fills it with the elements of a given big array.

Note that this constructor makes it easy to build big lists from literal arrays declared as type[][] {{ init_values }}. The only constraint is that the number of initialisation values is below BigArrays.SEGMENT_SIZE.

Parameters:

a - a big array whose elements will be used to fill the array list.

IntBigArrayBigList

public IntBigArrayBigList(int[][] a,
                  long offset,
                  long length)

Creates a new big-array big list and fills it with the elements of a given big array.

Note that this constructor makes it easy to build big lists from literal arrays declared as type[][] {{ init_values }}. The only constraint is that the number of initialisation values is below BigArrays.SEGMENT_SIZE.

Parameters:

a - a big array whose elements will be used to fill the array list.

offset - the first element to use.

length - the number of elements to use.

IntBigArrayBigList

public IntBigArrayBigList(Iterator<? extends Integer> i)

Creates a new big-array big list and fills it with the elements returned by an iterator..

Parameters:

i - an iterator whose returned elements will fill the array list.

IntBigArrayBigList

public IntBigArrayBigList(IntIterator i)

Creates a new big-array big list and fills it with the elements returned by a type-specific iterator..

Parameters:

i - a type-specific iterator whose returned elements will fill the array list.

Method Detail

elements

public int[][] elements()

Returns the backing big array of this big list.

Returns:

the backing big array.

wrap

public static IntBigArrayBigList wrap(int[][] a,
                      long length)

Wraps a given big array into a big-array list of given size.

Parameters:

a - a big array to wrap.

length - the length of the resulting big-array list.

Returns:

a new big-array list of the given size, wrapping the given big array.

wrap

public static IntBigArrayBigList wrap(int[][] a)

Wraps a given big array into a big-array big list.

Parameters:

a - a big array to wrap.

Returns:

a new big-array big list wrapping the given array.

ensureCapacity

public void ensureCapacity(long capacity)

Ensures that this big-array big list can contain the given number of entries without resizing.

Parameters:

capacity - the new minimum capacity for this big-array big list.

add

public void add(long index,
       int k)

Specified by:

add in interface IntBigList

Overrides:

add in class AbstractIntBigList

See Also:

List.add(int,Object)

add

public boolean add(int k)

Specified by:

add in interface IntCollection

Overrides:

add in class AbstractIntBigList

See Also:

Collection.add(Object)

getInt

public int getInt(long index)

Specified by:

getInt in interface IntBigList

See Also:

BigList.get(long)

indexOf

public long indexOf(int k)

Specified by:

indexOf in interface IntBigList

Overrides:

indexOf in class AbstractIntBigList

See Also:

BigList.indexOf(Object)

lastIndexOf

public long lastIndexOf(int k)

Specified by:

lastIndexOf in interface IntBigList

Overrides:

lastIndexOf in class AbstractIntBigList

See Also:

BigList.lastIndexOf(Object)

removeInt

public int removeInt(long index)

Specified by:

removeInt in interface IntBigList

Overrides:

removeInt in class AbstractIntBigList

See Also:

BigList.remove(long)

rem

public boolean rem(int k)

Description copied from interface: IntCollection

Note that this method should be called remove(), but the clash with the similarly named index-based method in the List interface forces us to use a distinguished name. For simplicity, the set interfaces reinstates remove().

Specified by:

rem in interface IntCollection

Overrides:

rem in class AbstractIntBigList

See Also:

Collection.remove(Object)

set

public int set(long index,
      int k)

Specified by:

set in interface IntBigList

Overrides:

set in class AbstractIntBigList

See Also:

BigList.set(long,Object)

clear

public void clear()

Specified by:

clear in interface Collection<Integer>

Overrides:

clear in class AbstractCollection<Integer>

size64

public long size64()

Description copied from interface: Size64

Returns the size of this data structure as a long.

Specified by:

size64 in interface Size64

Returns:

the size of this data structure.

size

public void size(long size)

Description copied from interface: BigList

Sets the size of this big list.

If the specified size is smaller than the current size, the last elements are discarded. Otherwise, they are filled with 0/null/false.

Specified by:

size in interface BigList<Integer>

Overrides:

size in class AbstractIntBigList

Parameters:

size - the new size.

isEmpty

public boolean isEmpty()

Description copied from interface: Stack

Checks whether the stack is empty.

Specified by:

isEmpty in interface Stack<Integer>

Specified by:

isEmpty in interface Collection<Integer>

Overrides:

isEmpty in class AbstractIntCollection

Returns:

true if the stack is empty.

trim

public void trim()

Trims this big-array big list so that the capacity is equal to the size.

See Also:

ArrayList.trimToSize()

trim

public void trim(long n)

Trims the backing big array if it is too large. If the current big array length is smaller than or equal to n, this method does nothing. Otherwise, it trims the big-array length to the maximum between n and size64().

This method is useful when reusing big lists. Clearing a big list leaves the big-array length untouched. If you are reusing a big list many times, you can call this method with a typical size to avoid keeping around a very large big array just because of a few large transient big lists.

Parameters:

n - the threshold for the trimming.

getElements

public void getElements(int from,
               int[][] a,
               long offset,
               long length)

Copies element of this type-specific list into the given big array using optimized system calls.

Parameters:

from - the start index (inclusive).

a - the destination big array.

offset - the offset into the destination array where to store the first element copied.

length - the number of elements to be copied.

removeElements

public void removeElements(int from,
                  int to)

Removes elements of this type-specific list using optimized system calls.

Parameters:

from - the start index (inclusive).

to - the end index (exclusive).

addElements

public void addElements(int index,
               int[][] a,
               long offset,
               long length)

Adds elements to this type-specific list using optimized system calls.

Parameters:

index - the index at which to add elements.

a - the big array containing the elements.

offset - the offset of the first element to add.

length - the number of elements to add.

listIterator

public IntBigListIterator listIterator(int index)

Overrides:

listIterator in class AbstractIntBigList

clone

public IntBigArrayBigList clone()

Overrides:

clone in class Object

equals

public boolean equals(IntBigArrayBigList l)

Compares this type-specific big-array list to another one.

This method exists only for sake of efficiency. The implementation inherited from the abstract implementation would already work.

Parameters:

l - a type-specific big-array list.

Returns:

true if the argument contains the same elements of this type-specific big-array list.

compareTo

public int compareTo(IntBigArrayBigList l)

Compares this big list to another big list.

This method exists only for sake of efficiency. The implementation inherited from the abstract implementation would already work.

Parameters:

l - a big list.

Returns:

a negative integer, zero, or a positive integer as this big list is lexicographically less than, equal to, or greater than the argument.