it.unimi.dsi.fastutil.objects

Class ObjectBigArrays

java.lang.Object

it.unimi.dsi.fastutil.objects.ObjectBigArrays

public final class ObjectBigArrays
extends Object

A class providing static methods and objects that do useful things with big arrays.

Since version 8.4.0, many methods previously in this class(e.g., length()) have been deprecated in favor of those in BigArrays, which can be imported statically.

Note that BinIO and TextIO contain several methods make it possible to load and save big arrays of primitive types as sequences of elements in DataInput format (i.e., not as objects) or as sequences of lines of text.

Warning: creating arrays using reflection, as it happens in ensureCapacity(Object[][],long,long) and grow(Object[][],long,long), is significantly slower than using new. This phenomenon is particularly evident in the first growth phases of an array reallocated with doubling (or similar) logic.

See Also:

BigArrays

Field Summary

Fields

Modifier and Type	Field and Description
static Object[][]	DEFAULT_EMPTY_BIG_ARRAY A static, final, empty big array to be used as default big array in allocations.
static Object[][]	EMPTY_BIG_ARRAY A static, final, empty big array.
static Hash.Strategy	HASH_STRATEGY A type-specific content-based hash strategy for big arrays.

Method Summary

Modifier and Type	Method and Description
static <K> long	binarySearch(K[][] a, K key, Comparator<K> c) Searches a big array for the specified value using the binary search algorithm and a specified comparator.
static <K> long	binarySearch(K[][] a, long from, long to, K key) Searches a range of the specified big array for the specified value using the binary search algorithm.
static <K> long	binarySearch(K[][] a, long from, long to, K key, Comparator<K> c) Searches a range of the specified big array for the specified value using the binary search algorithm and a specified comparator.
static <K> long	binarySearch(K[][] a, Object key) Searches a big array for the specified value using the binary search algorithm.
static <K> K[][]	copy(K[][] array) Deprecated. Please use the version in BigArrays.
static <K> void	copy(K[][] srcArray, long srcPos, K[][] destArray, long destPos, long length) Deprecated. Please use the version in BigArrays.
static <K> K[][]	copy(K[][] array, long offset, long length) Deprecated. Please use the version in BigArrays.
static <K> void	copyFromBig(K[][] srcArray, long srcPos, K[] destArray, int destPos, int length) Deprecated. Please use the version in BigArrays.
static <K> void	copyToBig(K[] srcArray, int srcPos, K[][] destArray, long destPos, long length) Deprecated. Please use the version in BigArrays.
static <K> K[][]	ensureCapacity(K[][] array, long length) Deprecated. Please use the version in BigArrays.
static <K> K[][]	ensureCapacity(K[][] array, long length, long preserve) Deprecated. Please use the version in BigArrays.
static <K> void	ensureFromTo(K[][] a, long from, long to) Deprecated. Please use the version in BigArrays.
static <K> void	ensureOffsetLength(K[][] a, long offset, long length) Deprecated. Please use the version in BigArrays.
static <K> void	ensureSameLength(K[][] a, K[][] b) Deprecated. Please use the version in BigArrays.
static <K> boolean	equals(K[][] a1, K[][] a2) Deprecated. Please use the version in BigArrays.
static <K> void	fill(K[][] array, K value) Deprecated. Please use the version in BigArrays.
static <K> void	fill(K[][] array, long from, long to, K value) Deprecated. Please use the version in BigArrays.
static <K> K[][]	forceCapacity(K[][] array, long length, long preserve) Deprecated. Please use the version in BigArrays.
static <K> K	get(K[][] array, long index) Deprecated. Please use the version in BigArrays.
static <K> K[][]	grow(K[][] array, long length) Deprecated. Please use the version in BigArrays.
static <K> K[][]	grow(K[][] array, long length, long preserve) Deprecated. Please use the version in BigArrays.
static <K> long	length(K[][] array) Deprecated. Please use the version in BigArrays.
static Object[][]	newBigArray(Class<?> componentType, long length) Creates a new big array using a given component type.
static <K> K[][]	newBigArray(K[][] prototype, long length) Creates a new big array using the given one as prototype.
static Object[][]	newBigArray(long length) Creates a new big array.
static <K> void	quickSort(K[][] x) Sorts the specified big array according to the natural ascending order using quicksort.
static <K> void	quickSort(K[][] x, Comparator<K> comp) Sorts the specified big array according to the order induced by the specified comparator using quicksort.
static <K> void	quickSort(K[][] x, long from, long to) Sorts the specified range of elements according to the natural ascending order using quicksort.
static <K> void	quickSort(K[][] x, long from, long to, Comparator<K> comp) Sorts the specified range of elements according to the order induced by the specified comparator using quicksort.
static <K> void	set(K[][] array, long index, K value) Deprecated. Please use the version in BigArrays.
static <K> K[][]	setLength(K[][] array, long length) Deprecated. Please use the version in BigArrays.
static <K> K[][]	shuffle(K[][] a, long from, long to, Random random) Shuffles the specified big array fragment using the specified pseudorandom number generator.
static <K> K[][]	shuffle(K[][] a, Random random) Shuffles the specified big array using the specified pseudorandom number generator.
static <K> void	swap(K[][] array, long first, long second) Deprecated. Please use the version in BigArrays.
static <K> String	toString(K[][] a) Deprecated.
static <K> K[][]	trim(K[][] array, long length) Deprecated. Please use the version in BigArrays.
static <K> K[][]	wrap(K[] array) Deprecated. Please use the version in BigArrays.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_BIG_ARRAY

public static final Object[][] EMPTY_BIG_ARRAY

A static, final, empty big array.

DEFAULT_EMPTY_BIG_ARRAY

public static final Object[][] DEFAULT_EMPTY_BIG_ARRAY

A static, final, empty big array to be used as default big array in allocations. An object distinct from EMPTY_BIG_ARRAY makes it possible to have different behaviors depending on whether the user required an empty allocation, or we are just lazily delaying allocation.

See Also:

ArrayList

HASH_STRATEGY

public static final Hash.Strategy HASH_STRATEGY

A type-specific content-based hash strategy for big arrays.

This hash strategy may be used in custom hash collections whenever keys are big arrays, and they must be considered equal by content. This strategy will handle null correctly, and it is serializable.

Method Detail

get

@Deprecated
public static <K> K get(K[][] array,
                                    long index)

Deprecated. Please use the version in BigArrays.

Returns the element of the given big array of specified index.

Parameters:

array - a big array.

index - a position in the big array.

Returns:

the element of the big array at the specified position.

set

@Deprecated
public static <K> void set(K[][] array,
                                       long index,
                                       K value)

Deprecated. Please use the version in BigArrays.

Sets the element of the given big array of specified index.

Parameters:

array - a big array.

index - a position in the big array.

value - the new value for the array element at the specified position.

swap

@Deprecated
public static <K> void swap(K[][] array,
                                        long first,
                                        long second)

Deprecated. Please use the version in BigArrays.

Swaps the element of the given big array of specified indices.

Parameters:

array - a big array.

first - a position in the big array.

second - a position in the big array.

length

@Deprecated
public static <K> long length(K[][] array)

Deprecated. Please use the version in BigArrays.

Returns the length of the given big array.

Parameters:

array - a big array.

Returns:

the length of the given big array.

copy

@Deprecated
public static <K> void copy(K[][] srcArray,
                                        long srcPos,
                                        K[][] destArray,
                                        long destPos,
                                        long length)

Deprecated. Please use the version in BigArrays.

Copies a big array from the specified source big array, beginning at the specified position, to the specified position of the destination big array. Handles correctly overlapping regions of the same big array.

Parameters:

srcArray - the source big array.

srcPos - the starting position in the source big array.

destArray - the destination big array.

destPos - the starting position in the destination data.

length - the number of elements to be copied.

copyFromBig

@Deprecated
public static <K> void copyFromBig(K[][] srcArray,
                                               long srcPos,
                                               K[] destArray,
                                               int destPos,
                                               int length)

Deprecated. Please use the version in BigArrays.

Copies a big array from the specified source big array, beginning at the specified position, to the specified position of the destination array.

Parameters:

srcArray - the source big array.

srcPos - the starting position in the source big array.

destArray - the destination array.

destPos - the starting position in the destination data.

length - the number of elements to be copied.

copyToBig

@Deprecated
public static <K> void copyToBig(K[] srcArray,
                                             int srcPos,
                                             K[][] destArray,
                                             long destPos,
                                             long length)

Deprecated. Please use the version in BigArrays.

Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination big array.

Parameters:

srcArray - the source array.

srcPos - the starting position in the source array.

destArray - the destination big array.

destPos - the starting position in the destination data.

length - the number of elements to be copied.

newBigArray

public static <K> K[][] newBigArray(K[][] prototype,
                                    long length)

Creates a new big array using the given one as prototype.

This method returns a new big array of the given length whose element are of the same class as of those of prototype. In case of an empty big array, it tries to return EMPTY_BIG_ARRAY, if possible.

Parameters:

prototype - a big array that will be used to type the new one.

length - the length of the new big array.

Returns:

a new big array of given type and length.

newBigArray

public static Object[][] newBigArray(Class<?> componentType,
                                     long length)

Creates a new big array using a given component type.

This method returns a new big array whose segments are of class componentType. In case of an empty big array, it tries to return EMPTY_BIG_ARRAY, if possible.

Parameters:

componentType - a class representing the type of segments of the array to be created.

length - the length of the new big array.

Returns:

a new big array of given type and length.

newBigArray

public static Object[][] newBigArray(long length)

Creates a new big array.

Parameters:

length - the length of the new big array.

Returns:

a new big array of given length.

wrap

@Deprecated
public static <K> K[][] wrap(K[] array)

Deprecated. Please use the version in BigArrays.

Turns a standard array into a big array.

Note that the returned big array might contain as a segment the original array.

Parameters:

array - an array.

Returns:

a new big array with the same length and content of array.

ensureCapacity

@Deprecated
public static <K> K[][] ensureCapacity(K[][] array,
                                                   long length)

Deprecated. Please use the version in BigArrays.

Ensures that a big array can contain the given number of entries.

If you cannot foresee whether this big array will need again to be enlarged, you should probably use grow() instead.

Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.

Parameters:

array - a big array.

length - the new minimum length for this big array.

Returns:

array, if it contains length entries or more; otherwise, a big array with length entries whose first length(array) entries are the same as those of array.

forceCapacity

@Deprecated
public static <K> K[][] forceCapacity(K[][] array,
                                                  long length,
                                                  long preserve)

Deprecated. Please use the version in BigArrays.

Forces a big array to contain the given number of entries, preserving just a part of the big array.

This method returns a new big array of the given length whose element are of the same class as of those of array.

Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.

Parameters:

array - a big array.

length - the new minimum length for this big array.

preserve - the number of elements of the big array that must be preserved in case a new allocation is necessary.

Returns:

a big array with length entries whose first preserve entries are the same as those of array.

ensureCapacity

@Deprecated
public static <K> K[][] ensureCapacity(K[][] array,
                                                   long length,
                                                   long preserve)

Deprecated. Please use the version in BigArrays.

Ensures that a big array can contain the given number of entries, preserving just a part of the big array.

This method returns a new big array of the given length whose element are of the same class as of those of array.

Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.

Parameters:

array - a big array.

length - the new minimum length for this big array.

preserve - the number of elements of the big array that must be preserved in case a new allocation is necessary.

Returns:

array, if it can contain length entries or more; otherwise, a big array with length entries whose first preserve entries are the same as those of array.

grow

@Deprecated
public static <K> K[][] grow(K[][] array,
                                         long length)

Deprecated. Please use the version in BigArrays.

Grows the given big array to the maximum between the given length and the current length increased by 50%, provided that the given length is larger than the current length.

If you want complete control on the big array growth, you should probably use ensureCapacity() instead.

Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.

Parameters:

array - a big array.

length - the new minimum length for this big array.

Returns:

array, if it can contain length entries; otherwise, a big array with max(length,length(array)/φ) entries whose first length(array) entries are the same as those of array.

grow

@Deprecated
public static <K> K[][] grow(K[][] array,
                                         long length,
                                         long preserve)

Deprecated. Please use the version in BigArrays.

Grows the given big array to the maximum between the given length and the current length increased by 50%, provided that the given length is larger than the current length, preserving just a part of the big array.

If you want complete control on the big array growth, you should probably use ensureCapacity() instead.

Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.

Parameters:

array - a big array.

length - the new minimum length for this big array.

preserve - the number of elements of the big array that must be preserved in case a new allocation is necessary.

Returns:

array, if it can contain length entries; otherwise, a big array with max(length,length(array)/φ) entries whose first preserve entries are the same as those of array.

trim

@Deprecated
public static <K> K[][] trim(K[][] array,
                                         long length)

Deprecated. Please use the version in BigArrays.

Trims the given big array to the given length.

Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.

Parameters:

array - a big array.

length - the new maximum length for the big array.

Returns:

array, if it contains length entries or less; otherwise, a big array with length entries whose entries are the same as the first length entries of array.

setLength

@Deprecated
public static <K> K[][] setLength(K[][] array,
                                              long length)

Deprecated. Please use the version in BigArrays.

Sets the length of the given big array.

Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.

Parameters:

array - a big array.

length - the new length for the big array.

Returns:

array, if it contains exactly length entries; otherwise, if it contains more than length entries, a big array with length entries whose entries are the same as the first length entries of array; otherwise, a big array with length entries whose first length(array) entries are the same as those of array.

copy

@Deprecated
public static <K> K[][] copy(K[][] array,
                                         long offset,
                                         long length)

Deprecated. Please use the version in BigArrays.

Returns a copy of a portion of a big array.

Parameters:

array - a big array.

offset - the first element to copy.

length - the number of elements to copy.

Returns:

a new big array containing length elements of array starting at offset.

copy

@Deprecated
public static <K> K[][] copy(K[][] array)

Deprecated. Please use the version in BigArrays.

Returns a copy of a big array.

Parameters:

array - a big array.

Returns:

a copy of array.

fill

@Deprecated
public static <K> void fill(K[][] array,
                                        K value)

Deprecated. Please use the version in BigArrays.

Fills the given big array with the given value.

This method uses a backward loop. It is significantly faster than the corresponding method in Arrays.

Parameters:

array - a big array.

value - the new value for all elements of the big array.

fill

@Deprecated
public static <K> void fill(K[][] array,
                                        long from,
                                        long to,
                                        K value)

Deprecated. Please use the version in BigArrays.

Fills a portion of the given big array with the given value.

If possible (i.e., from is 0) this method uses a backward loop. In this case, it is significantly faster than the corresponding method in Arrays.

Parameters:

array - a big array.

from - the starting index of the portion to fill.

to - the end index of the portion to fill.

value - the new value for all elements of the specified portion of the big array.

equals

@Deprecated
public static <K> boolean equals(K[][] a1,
                                             K[][] a2)

Deprecated. Please use the version in BigArrays.

Returns true if the two big arrays are elementwise equal.

This method uses a backward loop. It is significantly faster than the corresponding method in Arrays.

Parameters:

a1 - a big array.

a2 - another big array.

Returns:

true if the two big arrays are of the same length, and their elements are equal.

toString

@Deprecated
public static <K> String toString(K[][] a)

Deprecated.

ensureFromTo

@Deprecated
public static <K> void ensureFromTo(K[][] a,
                                                long from,
                                                long to)

Deprecated. Please use the version in BigArrays.

Ensures that a range given by its first (inclusive) and last (exclusive) elements fits a big array.

This method may be used whenever a big array range check is needed.

Parameters:

a - a big array.

from - a start index (inclusive).

to - an end index (inclusive).

Throws:

IllegalArgumentException - if from is greater than to.

ArrayIndexOutOfBoundsException - if from or to are greater than the big array length or negative.

ensureOffsetLength

@Deprecated
public static <K> void ensureOffsetLength(K[][] a,
                                                      long offset,
                                                      long length)

Deprecated. Please use the version in BigArrays.

Ensures that a range given by an offset and a length fits a big array.

This method may be used whenever a big array range check is needed.

Parameters:

a - a big array.

offset - a start index.

length - a length (the number of elements in the range).

Throws:

IllegalArgumentException - if length is negative.

ArrayIndexOutOfBoundsException - if offset is negative or offset+length is greater than the big array length.

ensureSameLength

@Deprecated
public static <K> void ensureSameLength(K[][] a,
                                                    K[][] b)

Deprecated. Please use the version in BigArrays.

Ensures that two big arrays are of the same length.

Parameters:

a - a big array.

b - another big array.

Throws:

IllegalArgumentException - if the two argument arrays are not of the same length.

quickSort

public static <K> void quickSort(K[][] x,
                                 long from,
                                 long to,
                                 Comparator<K> comp)

Sorts the specified range of elements according to the order induced by the specified comparator using quicksort.

The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.

Parameters:

x - the big array to be sorted.

from - the index of the first element (inclusive) to be sorted.

to - the index of the last element (exclusive) to be sorted.

comp - the comparator to determine the sorting order.

quickSort

public static <K> void quickSort(K[][] x,
                                 Comparator<K> comp)

Sorts the specified big array according to the order induced by the specified comparator using quicksort.

The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.

Parameters:

x - the big array to be sorted.

comp - the comparator to determine the sorting order.

quickSort

public static <K> void quickSort(K[][] x,
                                 long from,
                                 long to)

Sorts the specified range of elements according to the natural ascending order using quicksort.

The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.

Parameters:

x - the big array to be sorted.

from - the index of the first element (inclusive) to be sorted.

to - the index of the last element (exclusive) to be sorted.

quickSort

public static <K> void quickSort(K[][] x)

Sorts the specified big array according to the natural ascending order using quicksort.

The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.

Parameters:

x - the big array to be sorted.

binarySearch

public static <K> long binarySearch(K[][] a,
                                    long from,
                                    long to,
                                    K key)

Searches a range of the specified big array for the specified value using the binary search algorithm. The range must be sorted prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

Parameters:

a - the big array to be searched.

from - the index of the first element (inclusive) to be searched.

to - the index of the last element (exclusive) to be searched.

key - the value to be searched for.

Returns:

index of the search key, if it is contained in the big array; otherwise, (-(insertion point) - 1). The insertion point is defined as the the point at which the value would be inserted into the big array: the index of the first element greater than the key, or the length of the big array, if all elements in the big array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

See Also:

Arrays

binarySearch

public static <K> long binarySearch(K[][] a,
                                    Object key)

Searches a big array for the specified value using the binary search algorithm. The range must be sorted prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

Parameters:

a - the big array to be searched.

key - the value to be searched for.

Returns:

index of the search key, if it is contained in the big array; otherwise, (-(insertion point) - 1). The insertion point is defined as the the point at which the value would be inserted into the big array: the index of the first element greater than the key, or the length of the big array, if all elements in the big array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

See Also:

Arrays

binarySearch

public static <K> long binarySearch(K[][] a,
                                    long from,
                                    long to,
                                    K key,
                                    Comparator<K> c)

Searches a range of the specified big array for the specified value using the binary search algorithm and a specified comparator. The range must be sorted following the comparator prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

Parameters:

a - the big array to be searched.

from - the index of the first element (inclusive) to be searched.

to - the index of the last element (exclusive) to be searched.

key - the value to be searched for.

c - a comparator.

Returns:

index of the search key, if it is contained in the big array; otherwise, (-(insertion point) - 1). The insertion point is defined as the the point at which the value would be inserted into the big array: the index of the first element greater than the key, or the length of the big array, if all elements in the big array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

See Also:

Arrays

binarySearch

public static <K> long binarySearch(K[][] a,
                                    K key,
                                    Comparator<K> c)

Searches a big array for the specified value using the binary search algorithm and a specified comparator. The range must be sorted following the comparator prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.

Parameters:

a - the big array to be searched.

key - the value to be searched for.

c - a comparator.

Returns:

index of the search key, if it is contained in the big array; otherwise, (-(insertion point) - 1). The insertion point is defined as the the point at which the value would be inserted into the big array: the index of the first element greater than the key, or the length of the big array, if all elements in the big array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.

See Also:

Arrays

shuffle

public static <K> K[][] shuffle(K[][] a,
                                long from,
                                long to,
                                Random random)

Shuffles the specified big array fragment using the specified pseudorandom number generator.

Parameters:

a - the big array to be shuffled.

from - the index of the first element (inclusive) to be shuffled.

to - the index of the last element (exclusive) to be shuffled.

random - a pseudorandom number generator.

Returns:

a.

shuffle

public static <K> K[][] shuffle(K[][] a,
                                Random random)

Shuffles the specified big array using the specified pseudorandom number generator.

Parameters:

a - the big array to be shuffled.

random - a pseudorandom number generator.

Returns:

a.