public final class LongBigArrays
extends java.lang.Object
In particular, the forceCapacity()
, ensureCapacity()
,
grow()
, trim()
and setLength()
methods allow to
handle big arrays much like array lists.
Note that BinIO
and
TextIO
contain several methods that 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.
BigArrays
Modifier and Type  Field  Description 

static long[][] 
DEFAULT_EMPTY_BIG_ARRAY 
A static, final, empty big array to be used as default big array in
allocations.

static long[][] 
EMPTY_BIG_ARRAY 
A static, final, empty big array.

static Hash.Strategy 
HASH_STRATEGY 
A typespecific contentbased hash strategy for big arrays.

Modifier and Type  Method  Description 

static void 
add(long[][] array,
long index,
long incr) 
Adds the specified increment the element of the given big array of specified
index.

static long 
binarySearch(long[][] a,
long key) 
Searches a big array for the specified value using the binary search
algorithm.

static long 
binarySearch(long[][] a,
long from,
long to,
long key) 
Searches a range of the specified big array for the specified value using the
binary search algorithm.

static long 
binarySearch(long[][] a,
long from,
long to,
long key,
LongComparator c) 
Searches a range of the specified big array for the specified value using the
binary search algorithm and a specified comparator.

static long 
binarySearch(long[][] a,
long key,
LongComparator c) 
Searches a big array for the specified value using the binary search
algorithm and a specified comparator.

static long[][] 
copy(long[][] array) 
Returns a copy of a big array.

static long[][] 
copy(long[][] array,
long offset,
long length) 
Returns a copy of a portion of a big array.

static void 
copy(long[][] srcArray,
long srcPos,
long[][] destArray,
long destPos,
long length) 
Copies a big array from the specified source big array, beginning at the
specified position, to the specified position of the destination big array.

static void 
copyFromBig(long[][] srcArray,
long srcPos,
long[] destArray,
int destPos,
int length) 
Copies a big array from the specified source big array, beginning at the
specified position, to the specified position of the destination array.

static void 
copyToBig(long[] srcArray,
int srcPos,
long[][] destArray,
long destPos,
long length) 
Copies an array from the specified source array, beginning at the specified
position, to the specified position of the destination big array.

static void 
decr(long[][] array,
long index) 
Decrements the element of the given big array of specified index.

static long[][] 
ensureCapacity(long[][] array,
long length) 
Ensures that a big array can contain the given number of entries.

static long[][] 
ensureCapacity(long[][] array,
long length,
long preserve) 
Ensures that a big array can contain the given number of entries, preserving
just a part of the big array.

static void 
ensureFromTo(long[][] a,
long from,
long to) 
Ensures that a range given by its first (inclusive) and last (exclusive)
elements fits a big array.

static void 
ensureOffsetLength(long[][] a,
long offset,
long length) 
Ensures that a range given by an offset and a length fits a big array.

static boolean 
equals(long[][] a1,
long[][] a2) 
Returns true if the two big arrays are elementwise equal.

static void 
fill(long[][] array,
long value) 
Fills the given big array with the given value.

static void 
fill(long[][] array,
long from,
long to,
long value) 
Fills a portion of the given big array with the given value.

static long[][] 
forceCapacity(long[][] array,
long length,
long preserve) 
Forces a big array to contain the given number of entries, preserving just a
part of the big array.

static long 
get(long[][] array,
long index) 
Returns the element of the given big array of specified index.

static long[][] 
grow(long[][] array,
long length) 
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.

static long[][] 
grow(long[][] array,
long length,
long preserve) 
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.

static void 
incr(long[][] array,
long index) 
Increments the element of the given big array of specified index.

static long 
length(long[][] array) 
Returns the length of the given big array.

static void 
mul(long[][] array,
long index,
long factor) 
Multiplies by the specified factor the element of the given big array of
specified index.

static long[][] 
newBigArray(long length) 
Creates a new big array.

static void 
quickSort(long[][] x) 
Sorts the specified big array according to the natural ascending order using
quicksort.

static void 
quickSort(long[][] x,
long from,
long to) 
Sorts the specified range of elements according to the natural ascending
order using quicksort.

static void 
quickSort(long[][] x,
long from,
long to,
LongComparator comp) 
Sorts the specified range of elements according to the order induced by the
specified comparator using quicksort.

static void 
quickSort(long[][] x,
LongComparator comp) 
Sorts the specified big array according to the order induced by the specified
comparator using quicksort.

static void 
radixSort(long[][] a) 
Sorts the specified big array using radix sort.

static void 
radixSort(long[][] a,
long[][] b) 
Sorts the specified pair of big arrays lexicographically using radix sort.

static void 
radixSort(long[][] a,
long[][] b,
long from,
long to) 
Sorts the specified pair of big arrays lexicographically using radix sort.

static void 
radixSort(long[][] a,
long from,
long to) 
Sorts the specified big array using radix sort.

static void 
set(long[][] array,
long index,
long value) 
Sets the element of the given big array of specified index.

static long[][] 
setLength(long[][] array,
long length) 
Sets the length of the given big array.

static long[][] 
shuffle(long[][] a,
long from,
long to,
java.util.Random random) 
Shuffles the specified big array fragment using the specified pseudorandom
number generator.

static long[][] 
shuffle(long[][] a,
java.util.Random random) 
Shuffles the specified big array using the specified pseudorandom number
generator.

static void 
swap(long[][] array,
long first,
long second) 
Swaps the element of the given big array of specified indices.

static java.lang.String 
toString(long[][] a) 

static long[][] 
trim(long[][] array,
long length) 
Trims the given big array to the given length.

static long[][] 
wrap(long[] array) 
Turns a standard array into a big array.

public static final long[][] EMPTY_BIG_ARRAY
public static final long[][] DEFAULT_EMPTY_BIG_ARRAY
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.ArrayList
public static final Hash.Strategy HASH_STRATEGY
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.
public static long get(long[][] array, long index)
array
 a big array.index
 a position in the big array.public static void set(long[][] array, long index, long value)
array
 a big array.index
 a position in the big array.value
 the new value for the array element at the specified position.public static void swap(long[][] array, long first, long second)
array
 a big array.first
 a position in the big array.second
 a position in the big array.public static void add(long[][] array, long index, long incr)
array
 a big array.index
 a position in the big array.incr
 the incrementpublic static void mul(long[][] array, long index, long factor)
array
 a big array.index
 a position in the big array.factor
 the factorpublic static void incr(long[][] array, long index)
array
 a big array.index
 a position in the big array.public static void decr(long[][] array, long index)
array
 a big array.index
 a position in the big array.public static long length(long[][] array)
array
 a big array.public static void copy(long[][] srcArray, long srcPos, long[][] destArray, long destPos, long length)
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.public static void copyFromBig(long[][] srcArray, long srcPos, long[] destArray, int destPos, int length)
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.public static void copyToBig(long[] srcArray, int srcPos, long[][] destArray, long destPos, long length)
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.public static long[][] newBigArray(long length)
length
 the length of the new big array.public static long[][] wrap(long[] array)
Note that the returned big array might contain as a segment the original array.
array
 an array.array
.public static long[][] ensureCapacity(long[][] array, long length)
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 readonly after calling this method.
array
 a big array.length
 the new minimum length for this big array.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
.public static long[][] forceCapacity(long[][] array, long length, long preserve)
Warning: the returned array might use part of the segments of the original array, which must be considered readonly after calling this method.
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.length
entries whose first preserve
entries are the same as those of array
.public static long[][] ensureCapacity(long[][] array, long length, long preserve)
Warning: the returned array might use part of the segments of the original array, which must be considered readonly after calling this method.
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.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
.public static long[][] grow(long[][] array, long 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 readonly after calling this method.
array
 a big array.length
 the new minimum length for this big array.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
.public static long[][] grow(long[][] array, long length, long preserve)
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 readonly after calling this method.
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.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
.public static long[][] trim(long[][] array, long length)
Warning: the returned array might use part of the segments of the original array, which must be considered readonly after calling this method.
array
 a big array.length
 the new maximum length for the big array.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
.public static long[][] setLength(long[][] array, long length)
Warning: the returned array might use part of the segments of the original array, which must be considered readonly after calling this method.
array
 a big array.length
 the new length for the big array.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
.public static long[][] copy(long[][] array, long offset, long length)
array
 a big array.offset
 the first element to copy.length
 the number of elements to copy.length
elements of array
starting at offset
.public static long[][] copy(long[][] array)
array
 a big array.array
.public static void fill(long[][] array, long value)
This method uses a backward loop. It is significantly faster than the
corresponding method in Arrays
.
array
 a big array.value
 the new value for all elements of the big array.public static void fill(long[][] array, long from, long to, long 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
.
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.public static boolean equals(long[][] a1, long[][] a2)
This method uses a backward loop. It is significantly faster than the
corresponding method in Arrays
.
a1
 a big array.a2
 another big array.public static java.lang.String toString(long[][] a)
public static void ensureFromTo(long[][] a, long from, long to)
This method may be used whenever a big array range check is needed.
a
 a big array.from
 a start index (inclusive).to
 an end index (inclusive).java.lang.IllegalArgumentException
 if from
is greater than to
.java.lang.ArrayIndexOutOfBoundsException
 if from
or to
are greater than the big array
length or negative.public static void ensureOffsetLength(long[][] a, long offset, long length)
This method may be used whenever a big array range check is needed.
a
 a big array.offset
 a start index.length
 a length (the number of elements in the range).java.lang.IllegalArgumentException
 if length
is negative.java.lang.ArrayIndexOutOfBoundsException
 if offset
is negative or offset
+length
is
greater than the big array length.public static void quickSort(long[][] x, long from, long to, LongComparator comp)
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.
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.public static void quickSort(long[][] x, LongComparator comp)
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.
x
 the big array to be sorted.comp
 the comparator to determine the sorting order.public static void quickSort(long[][] x, long from, long to)
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.
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.public static void quickSort(long[][] x)
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.
x
 the big array to be sorted.public static long binarySearch(long[][] a, long from, long to, long key)
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.Arrays
public static long binarySearch(long[][] a, long key)
a
 the big array to be searched.key
 the value to be searched for.Arrays
public static long binarySearch(long[][] a, long from, long to, long key, LongComparator c)
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.Arrays
public static long binarySearch(long[][] a, long key, LongComparator c)
a
 the big array to be searched.key
 the value to be searched for.c
 a comparator.Arrays
public static void radixSort(long[][] a)
The sorting algorithm is a tuned radix sort adapted from Peter M. McIlroy, Keith Bostic and M. Douglas McIlroy, “Engineering radix sort”, Computing Systems, 6(1), pages 5−27 (1993), and further improved using the digitoracle idea described by Juha Kärkkäinen and Tommi Rantala in “Engineering radix sort for strings”, String Processing and Information Retrieval, 15th International Symposium, volume 5280 of Lecture Notes in Computer Science, pages 3−14, Springer (2008).
This implementation is significantly faster than quicksort already at small sizes (say, more than 10000 elements), but it can only sort in ascending order. It will allocate a support array of bytes with the same number of elements as the array to be sorted.
a
 the big array to be sorted.public static void radixSort(long[][] a, long from, long to)
The sorting algorithm is a tuned radix sort adapted from Peter M. McIlroy, Keith Bostic and M. Douglas McIlroy, “Engineering radix sort”, Computing Systems, 6(1), pages 5−27 (1993), and further improved using the digitoracle idea described by Juha Kärkkäinen and Tommi Rantala in “Engineering radix sort for strings”, String Processing and Information Retrieval, 15th International Symposium, volume 5280 of Lecture Notes in Computer Science, pages 3−14, Springer (2008).
This implementation is significantly faster than quicksort already at small sizes (say, more than 10000 elements), but it can only sort in ascending order. It will allocate a support array of bytes with the same number of elements as the array to be sorted.
a
 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.public static void radixSort(long[][] a, long[][] b)
The sorting algorithm is a tuned radix sort adapted from Peter M. McIlroy, Keith Bostic and M. Douglas McIlroy, “Engineering radix sort”, Computing Systems, 6(1), pages 5−27 (1993), and further improved using the digitoracle idea described by Juha Kärkkäinen and Tommi Rantala in “Engineering radix sort for strings”, String Processing and Information Retrieval, 15th International Symposium, volume 5280 of Lecture Notes in Computer Science, pages 3−14, Springer (2008).
This method implements a lexicographical sorting of the arguments.
Pairs of elements in the same position in the two provided arrays will be
considered a single key, and permuted accordingly. In the end, either
a[i] < a[i + 1]
or a[i] == a[i + 1]
and
b[i] <= b[i + 1]
.
This implementation is significantly faster than quicksort already at small sizes (say, more than 10000 elements), but it can only sort in ascending order. It will allocate a support array of bytes with the same number of elements as the arrays to be sorted.
a
 the first big array to be sorted.b
 the second big array to be sorted.public static void radixSort(long[][] a, long[][] b, long from, long to)
The sorting algorithm is a tuned radix sort adapted from Peter M. McIlroy, Keith Bostic and M. Douglas McIlroy, “Engineering radix sort”, Computing Systems, 6(1), pages 5−27 (1993), and further improved using the digitoracle idea described by Juha Kärkkäinen and Tommi Rantala in “Engineering radix sort for strings”, String Processing and Information Retrieval, 15th International Symposium, volume 5280 of Lecture Notes in Computer Science, pages 3−14, Springer (2008).
This method implements a lexicographical sorting of the arguments.
Pairs of elements in the same position in the two provided arrays will be
considered a single key, and permuted accordingly. In the end, either
a[i] < a[i + 1]
or a[i] == a[i + 1]
and
b[i] <= b[i + 1]
.
This implementation is significantly faster than quicksort already at small sizes (say, more than 10000 elements), but it can only sort in ascending order. It will allocate a support array of bytes with the same number of elements as the arrays to be sorted.
a
 the first big array to be sorted.b
 the second 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.public static long[][] shuffle(long[][] a, long from, long to, java.util.Random random)
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.a
.public static long[][] shuffle(long[][] a, java.util.Random random)
a
 the big array to be shuffled.random
 a pseudorandom number generator.a
.