FOodleCompressedArray Namespace Reference

Functions
bool CORE_API	CompressData (TArray< uint8 > &OutCompressed, const void *InData, int32 InDataSize, FOodleDataCompression::ECompressor InCompressor, FOodleDataCompression::ECompressionLevel InLevel)
bool CORE_API	CompressData64 (TArray64< uint8 > &OutCompressed, const void *InData, int64 InDataSize, FOodleDataCompression::ECompressor InCompressor, FOodleDataCompression::ECompressionLevel InLevel)
bool CORE_API	DecompressToExistingBuffer (void *InDestinationBuffer, int64 InDestinationBufferSize, TArray< uint8 > const &InCompressed)
bool CORE_API	DecompressToExistingBuffer64 (void *InDestinationBuffer, int64 InDestinationBufferSize, TArray64< uint8 > const &InCompressed)
bool CORE_API	DecompressToAllocatedBuffer (void *&OutDestinationBuffer, int32 &OutDestinationBufferSize, TArray< uint8 > const &InCompressed)
bool CORE_API	DecompressToAllocatedBuffer64 (void *&OutDestinationBuffer, int64 &OutDestinationBufferSize, TArray64< uint8 > const &InCompressed)
int32	PeekSizes (TArray< uint8 > const &InCompressed, int32 &OutCompressedSize, int32 &OutDecompressedSize)
int32	PeekSizes64 (TArray64< uint8 > const &InCompressed, int64 &OutCompressedSize, int64 &OutDecompressedSize)
template<class T >
bool	CompressTArray (TArray< uint8 > &OutCompressed, const TArray< T > &InBuffer, FOodleDataCompression::ECompressor InCompressor, FOodleDataCompression::ECompressionLevel InLevel)
template<class T >
bool	CompressTArray64 (TArray64< uint8 > &OutCompressed, const TArray64< T > &InBuffer, FOodleDataCompression::ECompressor InCompressor, FOodleDataCompression::ECompressionLevel InLevel)
template<class T >
bool	DecompressToTArray (TArray< T > &OutDecompressed, TArray< uint8 > const &InCompressed)
template<class T >
bool	DecompressToTArray64 (TArray64< T > &OutDecompressed, TArray64< uint8 > const &InCompressed)

Detailed Description

Represents a compressed buffer prefixed with the compressed and decompressed size. The compressed size is technically double-specified, but affords writing the buffer to disk without any further header. This header is variable sized based on need - 32 bits unless the sizes require it, then its 64 bit.

This is distinct from FCompressedBuffer as it has less overhead, is not intended to seamlessly interface with IoStore, and only supports built-in Oodle.

NOTE any data that will be staged to a pak/iostore should NOT be compressed, as that system will compress for you in a manner appropriate for the platform!

If you just want raw pointers, call OodleDataCompress/Decompress directly.

Function Documentation

CompressData()

bool CORE_API FOodleCompressedArray::CompressData	(	TArray< uint8 > &	OutCompressed,
		const void *	InData,
		int32	InDataSize,
		FOodleDataCompression::ECompressor	InCompressor,
		FOodleDataCompression::ECompressionLevel	InLevel
	)

Compress an arbitrary data pointer, replacing existing data.

Parameters

OutCompressed	The destination TArray.
InData	The memory to compress.
InDataSize	The number of bytes in the InData buffer.
InCompressor	The Oodle compressor to use. See discussion.
InLevel	The compression level to use. See discussion.

Returns

Success or failure. Failure is usually bad parameter or out-of-memory.

Oodle exposes two knobs for compression - the compression type and the compression level. Type more or less trades decompression speed for compression ratio, and level more or less trades compression speed for ratio.

This makes selection very usage case specific, and it's tough to just recommend a one-size-fits-all parameter set. If you have access to Epic Slack, ask in oodle-dev. Some more detailed explanation exists adjacent to the EOodleDataCompressor and EOodleDataCompressionLevel declarations.

For common use cases, reference GetCompressorAndLevelForCommonUsage()

NOTE any data that will be staged to a pak/iostore should NOT be compressed, as that system will compress for you in a manner appropriate for the platform!

CompressData64()

bool CORE_API FOodleCompressedArray::CompressData64	(	TArray64< uint8 > &	OutCompressed,
		const void *	InData,
		int64	InDataSize,
		FOodleDataCompression::ECompressor	InCompressor,
		FOodleDataCompression::ECompressionLevel	InLevel
	)

CompressTArray()

template<class T >

bool FOodleCompressedArray::CompressTArray	(	TArray< uint8 > &	OutCompressed,
		const TArray< T > &	InBuffer,
		FOodleDataCompression::ECompressor	InCompressor,
		FOodleDataCompression::ECompressionLevel	InLevel
	)

Compress an arbitrary data pointer, replacing existing data.

This is just a thunk to CompressData, and exists just for type safety so everyone doesn't have to pull out the raw data from their TArrays.

See CompressData for parameter discussion.

CompressTArray64()

template<class T >

bool FOodleCompressedArray::CompressTArray64	(	TArray64< uint8 > &	OutCompressed,
		const TArray64< T > &	InBuffer,
		FOodleDataCompression::ECompressor	InCompressor,
		FOodleDataCompression::ECompressionLevel	InLevel
	)

DecompressToAllocatedBuffer()

bool CORE_API FOodleCompressedArray::DecompressToAllocatedBuffer	(	void *&	OutDestinationBuffer,
		int32 &	OutDestinationBufferSize,
		TArray< uint8 > const &	InCompressed
	)

Decompresses a compressed TArray to a buffer that will be allocated by this function.

Parameters

OutDestinationBuffer	The pointer to contain the allocated buffer that contains the decompressed data.
OutDestinationBufferSize	Will recieve the size of the buffer allocated.
InCompressed	A TArray created by one of the FOodleCompressedArray compression functions.

Returns

Success or failure. Failure is usually because the TArray doesn't actually contain any data, but might fail because 64 bit is needed.

DecompressToAllocatedBuffer64()

bool CORE_API FOodleCompressedArray::DecompressToAllocatedBuffer64	(	void *&	OutDestinationBuffer,
		int64 &	OutDestinationBufferSize,
		TArray64< uint8 > const &	InCompressed
	)

DecompressToExistingBuffer()

bool CORE_API FOodleCompressedArray::DecompressToExistingBuffer	(	void *	InDestinationBuffer,
		int64	InDestinationBufferSize,
		TArray< uint8 > const &	InCompressed
	)

Decompresses a compressed TArray to a buffer that has already been allocated.

Parameters

InDestinationBuffer	The buffer to contain the decompressed data.
InDestinationBufferSize	Allocated size of InDestinationBuffer; if it is not large enough to hold the decompressed data (as reported by PeekSizes), this function will return false.
InCompressed	A TArray created by one of the FOodleCompressedArray compression functions.

Returns

Success or failure. Failure is usually because the FCompressedArray doesn't actually contain any data, but might fail because 64 bit is needed.

DecompressToExistingBuffer64()

bool CORE_API FOodleCompressedArray::DecompressToExistingBuffer64	(	void *	InDestinationBuffer,
		int64	InDestinationBufferSize,
		TArray64< uint8 > const &	InCompressed
	)

DecompressToTArray()

template<class T >

bool FOodleCompressedArray::DecompressToTArray	(	TArray< T > &	OutDecompressed,
		TArray< uint8 > const &	InCompressed
	)

Decompress to a TArray. This should be paired with CompressTArray.

Parameters

OutDecompressed	The output TArray. Existing contents will be destroyed.
InCompressed	A TArray created by one of the FOodleCompressedArray compression functions.

Returns

Success or failure. Note that if the compress/decompress TArray types are mismatched (i.e. have different sizes) this could fail due to granularity concerns.

DecompressToTArray64()

template<class T >

bool FOodleCompressedArray::DecompressToTArray64	(	TArray64< T > &	OutDecompressed,
		TArray64< uint8 > const &	InCompressed
	)

PeekSizes()

int32 FOodleCompressedArray::PeekSizes ( TArray< uint8 > const &  InCompressed, int32 &  OutCompressedSize, int32 &  OutDecompressedSize  )

inline

Provides access to the compressed and decompressed sizes.

Parameters

InCompressed	A TArray generated by a call to one of the FOodleCompressedArray compression functions.
OutCompressedSize	The amount of compressed data (The array Num() is this plus the header size).
OutDecompressedSize	The number of bytes decompressing the data will produce.

Returns

0 if the FCompressedArray isn't valid, or if the compressed array requires PeekSizes64. Otherwise, the offset to the compressed data in the array.

PeekSizes64()

int32 FOodleCompressedArray::PeekSizes64 ( TArray64< uint8 > const &  InCompressed, int64 &  OutCompressedSize, int64 &  OutDecompressedSize  )

inline