Class CollectionHelper

Provides helper methods for collections.

Inheritance

CollectionHelper

Namespace: Unity.Collections

Assembly: Unity.Collections.dll

Syntax

public static class CollectionHelper

Fields

CacheLineSize

The size in bytes of the current platform's L1 cache lines.

Declaration

public const int CacheLineSize = 64

Field Value

Type	Description
int	The size in bytes of the current platform's L1 cache lines.

Methods

Align(int, int)

Returns an allocation size in bytes that factors in alignment.

Declaration

public static int Align(int size, int alignmentPowerOfTwo)

Parameters

Type	Name	Description
int	size	The size to align.
int	alignmentPowerOfTwo	A non-zero, positive power of two.

Returns

Type	Description
int	The smallest integer that is greater than or equal to `size` and is a multiple of `alignmentPowerOfTwo`.

Examples

  // 55 aligned to 16 is 64.
             int size = CollectionHelper.Align(55, 16);

Exceptions

Type	Condition
ArgumentException	Thrown if `alignmentPowerOfTwo` is not a non-zero, positive power of two.

Align(ulong, ulong)

Returns an allocation size in bytes that factors in alignment.

Declaration

public static ulong Align(ulong size, ulong alignmentPowerOfTwo)

Parameters

Type	Name	Description
ulong	size	The size to align.
ulong	alignmentPowerOfTwo	A non-zero, positive power of two.

Returns

Type	Description
ulong	The smallest integer that is greater than or equal to `size` and is a multiple of `alignmentPowerOfTwo`.

Examples

  // 55 aligned to 16 is 64.
             ulong size = CollectionHelper.Align(55, 16);

Exceptions

Type	Condition
ArgumentException	Thrown if `alignmentPowerOfTwo` is not a non-zero, positive power of two.

CreateNativeArray<T>(int, AllocatorHandle, NativeArrayOptions)

Create a NativeArray, using a provided AllocatorHandle.

Declaration

public static NativeArray<T> CreateNativeArray<T>(int length, AllocatorManager.AllocatorHandle allocator, NativeArrayOptions options = NativeArrayOptions.ClearMemory) where T : struct

Parameters

Type	Name	Description
int	length	The number of elements to allocate.
AllocatorManager.AllocatorHandle	allocator	The AllocatorHandle to use.
NativeArrayOptions	options	Options for allocation, such as whether to clear the memory.

Returns

Type	Description
NativeArray<T>	Returns the NativeArray that was created.

Type Parameters

Name	Description
T

CreateNativeArray<T>(NativeArray<T>, AllocatorHandle)

Create a NativeArray from another NativeArray, using a provided AllocatorHandle.

Declaration

public static NativeArray<T> CreateNativeArray<T>(NativeArray<T> array, AllocatorManager.AllocatorHandle allocator) where T : struct

Parameters

Type	Name	Description
NativeArray<T>	array	The NativeArray to make a copy of.
AllocatorManager.AllocatorHandle	allocator	The AllocatorHandle to use.

Returns

Type	Description
NativeArray<T>	Returns the NativeArray that was created.

Type Parameters

Name	Description
T

CreateNativeArray<T>(T[], AllocatorHandle)

Create a NativeArray from a managed array, using a provided AllocatorHandle.

Declaration

public static NativeArray<T> CreateNativeArray<T>(T[] array, AllocatorManager.AllocatorHandle allocator) where T : struct

Parameters

Type	Name	Description
T[]	array	The managed array to make a copy of.
AllocatorManager.AllocatorHandle	allocator	The AllocatorHandle to use.

Returns

Type	Description
NativeArray<T>	Returns the NativeArray that was created.

Type Parameters

Name	Description
T

CreateNativeArray<T, U>(int, ref U, NativeArrayOptions)

Create a NativeArray, using a provided allocator that implements IAllocator.

Declaration

public static NativeArray<T> CreateNativeArray<T, U>(int length, ref U allocator, NativeArrayOptions options = NativeArrayOptions.ClearMemory) where T : struct where U : unmanaged, AllocatorManager.IAllocator

Parameters

Type	Name	Description
int	length	The number of elements to allocate.
U	allocator	The allocator to use.
NativeArrayOptions	options	Options for allocation, such as whether to clear the memory.

Returns

Type	Description
NativeArray<T>	Returns the NativeArray that was created.

Type Parameters

Name	Description
T
U

CreateNativeArray<T, U>(T[], ref U)

Create a NativeArray from a managed array, using a provided Allocator.

Declaration

public static NativeArray<T> CreateNativeArray<T, U>(T[] array, ref U allocator) where T : struct where U : unmanaged, AllocatorManager.IAllocator

Parameters

Type	Name	Description
T[]	array	The managed array to make a copy of.
U	allocator	The Allocator to use.

Returns

Type	Description
NativeArray<T>	Returns the NativeArray that was created.

Type Parameters

Name	Description
T
U

CreateNativeMultiHashMap<TKey, TValue, U>(int, ref U)

Create a NativeMultiHashMap from a managed array, using a provided Allocator.

Declaration

public static NativeMultiHashMap<TKey, TValue> CreateNativeMultiHashMap<TKey, TValue, U>(int length, ref U allocator) where TKey : struct, IEquatable<TKey> where TValue : struct where U : unmanaged, AllocatorManager.IAllocator

Parameters

Type	Name	Description
int	length	The desired capacity of the NativeMultiHashMap.
U	allocator	The Allocator to use.

Returns

Type	Description
NativeMultiHashMap<TKey, TValue>	Returns the NativeMultiHashMap that was created.

Type Parameters

Name	Description
TKey
TValue
U

Hash(void*, int)

Returns a (non-cryptographic) hash of a memory block.

Declaration

public static uint Hash(void* ptr, int bytes)

Parameters

Type	Name	Description
void*	ptr	A buffer.
int	bytes	The number of bytes to hash.

Returns

Type	Description
uint	A hash of the bytes.

Remarks

The hash function used is djb2.

IsAligned(ulong, int)

Returns true if an offset has a given alignment.

Declaration

public static bool IsAligned(ulong offset, int alignmentPowerOfTwo)

Parameters

Type	Name	Description
ulong	offset	An offset
int	alignmentPowerOfTwo	A non-zero, positive power of two.

Returns

Type	Description
bool	True if the offset is a multiple of `alignmentPowerOfTwo`.

Exceptions

Type	Condition
ArgumentException	Thrown if `alignmentPowerOfTwo` is not a non-zero, positive power of two.

IsAligned(void*, int)

Returns true if the address represented by the pointer has a given alignment.

Declaration

public static bool IsAligned(void* p, int alignmentPowerOfTwo)

Parameters

Type	Name	Description
void*	p	The pointer.
int	alignmentPowerOfTwo	A non-zero, positive power of two.

Returns

Type	Description
bool	True if the address is a multiple of `alignmentPowerOfTwo`.

Exceptions

Type	Condition
ArgumentException	Thrown if `alignmentPowerOfTwo` is not a non-zero, positive power of two.

IsPowerOfTwo(int)

Returns true if a positive value is a non-zero power of two.

Declaration

public static bool IsPowerOfTwo(int value)

Parameters

Type	Name	Description
int	value	A positive value.

Returns

Type	Description
bool	True if the value is a non-zero, positive power of two.

Remarks

Result is invalid if value < 0.

Log2Ceil(int)

Returns the binary logarithm of the value, but the result is rounded up to the nearest integer.

Declaration

public static int Log2Ceil(int value)

Parameters

Type	Name	Description
int	value	The value.

Returns

Type	Description
int	The binary logarithm of the `value`, but the result is rounded up to the nearest integer.

Log2Floor(int)

Returns the binary logarithm of the value, but the result is rounded down to the nearest integer.

Declaration

public static int Log2Floor(int value)

Parameters

Type	Name	Description
int	value	The value.

Returns

Type	Description
int	The binary logarithm of the `value`, but the result is rounded down to the nearest integer.