UE::CompressedBuffer::Private::FHeader Struct Reference

Public Member Functions
void	Write (const FMutableMemoryView HeaderView) const
void	ByteSwap ()
bool	TryGetCompressParameters (ECompressedBufferCompressor &OutCompressor, ECompressedBufferCompressionLevel &OutCompressionLevel, uint64 &OutBlockSize) const

Static Public Member Functions
static bool	IsValid (const FCompositeBuffer &CompressedData)
static bool	IsValid (const FSharedBuffer &CompressedData)
static FHeader	Read (const FCompositeBuffer &CompressedData)
static uint32	CalculateCrc32 (const FMemoryView HeaderView)

Public Attributes
uint32	Magic = ExpectedMagic
uint32	Crc32 = 0
EMethod	Method = EMethod::None
uint8	Compressor = 0
uint8	CompressionLevel = 0
uint8	BlockSizeExponent = 0
uint32	BlockCount = 0
uint64	TotalRawSize = 0
uint64	TotalCompressedSize = 0
FBlake3Hash	RawHash

Static Public Attributes
static constexpr uint32	ExpectedMagic = 0xb7756362

Detailed Description

Header used on every compressed buffer. Always stored in big-endian format.

Member Function Documentation

ByteSwap()

void UE::CompressedBuffer::Private::FHeader::ByteSwap ( )

inline

CalculateCrc32()

static uint32 UE::CompressedBuffer::Private::FHeader::CalculateCrc32 ( const FMemoryView  HeaderView )

inlinestatic

Calculate the CRC-32 from a view of a header including any method-specific header data.

IsValid() [1/2]

bool UE::CompressedBuffer::Private::FHeader::IsValid ( const FCompositeBuffer &  CompressedData )

static

Checks validity of the buffer based on the magic number, method, and CRC-32.

IsValid() [2/2]

static bool UE::CompressedBuffer::Private::FHeader::IsValid ( const FSharedBuffer &  CompressedData )

inlinestatic

Read()

static FHeader UE::CompressedBuffer::Private::FHeader::Read ( const FCompositeBuffer &  CompressedData )

inlinestatic

Read a header from a buffer that is at least sizeof(FHeader) without any validation.

TryGetCompressParameters()

bool UE::CompressedBuffer::Private::FHeader::TryGetCompressParameters ( ECompressedBufferCompressor &  OutCompressor, ECompressedBufferCompressionLevel &  OutCompressionLevel, uint64 &  OutBlockSize  ) const

inline

Write()

void UE::CompressedBuffer::Private::FHeader::Write ( const FMutableMemoryView  HeaderView ) const

inline

Write a header to a memory view that is at least sizeof(FHeader).

Parameters

HeaderView

View of the header to write, including any method-specific header data.

Member Data Documentation

BlockCount

uint32 UE::CompressedBuffer::Private::FHeader::BlockCount = 0

The number of blocks that follow the header.

BlockSizeExponent

uint8 UE::CompressedBuffer::Private::FHeader::BlockSizeExponent = 0

The power of two size of every uncompressed block except the last. Size is 1 << BlockSizeExponent.

CompressionLevel

uint8 UE::CompressedBuffer::Private::FHeader::CompressionLevel = 0

The method-specific compression level used to compress the buffer.

Compressor

uint8 UE::CompressedBuffer::Private::FHeader::Compressor = 0

The method-specific compressor used to compress the buffer.

Crc32

uint32 UE::CompressedBuffer::Private::FHeader::Crc32 = 0

A CRC-32 used to check integrity of the buffer. Uses the polynomial 0x04c11db7.

ExpectedMagic

constexpr uint32 UE::CompressedBuffer::Private::FHeader::ExpectedMagic = 0xb7756362

staticconstexpr

Magic

uint32 UE::CompressedBuffer::Private::FHeader::Magic = ExpectedMagic

A magic number to identify a compressed buffer. Always 0xb7756362.

Method

EMethod UE::CompressedBuffer::Private::FHeader::Method = EMethod::None

The method used to compress the buffer. Affects layout of data following the header.

RawHash

FBlake3Hash UE::CompressedBuffer::Private::FHeader::RawHash

The hash of the uncompressed data.

TotalCompressedSize

uint64 UE::CompressedBuffer::Private::FHeader::TotalCompressedSize = 0

The total size of the compressed data including the header.

TotalRawSize

uint64 UE::CompressedBuffer::Private::FHeader::TotalRawSize = 0

The total size of the uncompressed data.

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The documentation for this struct was generated from the following file:

• Engine/Source/Runtime/Core/Private/Compression/CompressedBuffer.cpp