FIoHash | Unreal Engine 4.27 Documentation

Unreal Engine C++ API Reference > Runtime > Core > IO

References


Module	Core
Header	/Engine/Source/Runtime/Core/Public/IO/IoHash.h
Include	#include "IO/IoHash.h"

Syntax

struct FIoHash

Remarks

Stores a BLAKE3-160 hash, taken from the first 20 bytes of a BLAKE3-256 hash.

The BLAKE3 hash function was selected for its high performance and its ability to parallelize. Only the leading 160 bits of the 256-bit hash are used, to provide strong collision resistance while minimizing the size of the hash.

When the data to hash is not in a contiguous region of memory, use FIoHashBuilder to hash data in blocks with FIoHashBuilder::Update(Block) followed by FIoHashBuilder::Finalize().

Constructors

	Type	Name	Description
		FIoHash ()	Construct a zero hash.
		FIoHash ( const ByteArray& Hash )	Construct a hash from an array of 20 bytes.
		FIoHash ( const FBlake3Hash& Hash )	Construct a hash from a BLAKE3-256 hash.
		FIoHash ( FAnsiStringView HexHash )	Construct a hash from a 40-character hex string.
		FIoHash ( FWideStringView HexHash )	Construct a zero hash.
		FIoHash ( FUtf8StringView HexHash )	Construct a zero hash.

Functions

Type	Name	Description
FIoHash	FromView ( FMemoryView Hash )	Construct a hash from a view of 20 bytes.
ByteArray &	GetBytes ()	Returns a reference to the raw byte array for the hash.
const ByteArray &	GetBytes ()
FIoHash	HashBuffer ( FMemoryView View )	Calculate the hash of the buffer.
FIoHash	HashBuffer ( const FCompositeBuffer& Buffer )	Calculate the hash of the buffer.
FIoHash	HashBuffer ( const void* Data, uint64 Size )	Calculate the hash of the buffer.
bool	IsZero ()	Returns whether this is a zero hash.
void	Reset ()	Reset this to a zero hash.

Typedefs

Name	Description
ByteArray

Constants

Name	Description
Zero	A zero hash.

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