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FCompression

API > API/Runtime > API/Runtime/Core

   
Name FCompression
Type struct
Header File /Engine/Source/Runtime/Core/Public/Misc/Compression.h
Include Path #include "Misc/Compression.h"

Syntax

struct FCompression

Constants

Name Type Remarks Include Path
CompressionFormats TMap< FName, struct ICompressionFormat * > Mapping of Compression FNames to their compressor objects Misc/Compression.h
CompressionFormatsCriticalSection FCriticalSection   Misc/Compression.h
CompressorDstBytes TAtomic< uint64 > Number of bytes after compression.  

Nubmer of bytes after compression. | Misc/Compression.h |

CompressorSrcBytes TAtomic< uint64 > Number of bytes before compression. Misc/Compression.h
CompressorTimeCycles TAtomic< uint64 > CompressionData is per-compressor data passed through this API and is interpreted by the codecs. Misc/Compression.h

Functions

Static

Name Remarks Include Path Unreal Specifiers

static bool CompressMemory ( FName FormatName,
void* CompressedBuffer,
int64& CompressedSize,
const void* UncompressedBuffer,
int64 UncompressedSize,
ECompressionFlags Flags,
uintptr_t CompressionData
)

 Thread-safe abstract compression routine. Misc/Compression.h  

static bool CompressMemory ( FName FormatName,
void* CompressedBuffer,
int32& CompressedSize,
const void* UncompressedBuffer,
int32 UncompressedSize,
ECompressionFlags Flags,
int32 CompressionData
)

 Thunks to 64 bit CompressMemory, favor that. Misc/Compression.h  

static bool CompressMemoryBound ( FName InFormatName,
int64& OutBufferSizeRequired,
int64 InUncompressedSizeBytes,
uintptr_t InCompressionData
)

 Thread-safe abstract compression routine to query buffer requirements for a compression operation. Misc/Compression.h  

static int32 CompressMemoryBound ( FName FormatName,
int32 UncompressedSize,
ECompressionFlags Flags,
int32 CompressionData
)

 Thunks to the 64 bit, prefer that as this can only Fatal on error! Misc/Compression.h  

static bool CompressMemoryIfWorthDecompressing ( FName FormatName,
int32 MinBytesSaved,
int32 MinPercentSaved,
void* CompressedBuffer,
int32& CompressedSize,
const void* UncompressedBuffer,
int32 UncompressedSize,
ECompressionFlags Flags,
int32 CompressionData
)

 32 bit thunk. This legacy function doens't separate bOutWasCompressed vs general compress failure and will return false in both cases. Misc/Compression.h  

static bool CompressMemoryIfWorthDecompressing ( FName FormatName,
bool& bOutWasCompressed,
int64 MinBytesSaved,
int32 MinPercentSaved,
void* CompressedBuffer,
int64& CompressedSize,
const void* UncompressedBuffer,
int64 UncompressedSize,
ECompressionFlags Flags,
uintptr_t CompressionData
)

 Same as CompressMemory but evaluates if the compression gain is worth the runtime decode time. Misc/Compression.h  

static ICompressionFormat * GetCompressionFormat ( FName Method,
bool bErrorOnFailure
)

 Find a compression format module by name, returning nullptr if no module found Misc/Compression.h  

static FName GetCompressionFormatFromDeprecatedFlags ( ECompressionFlags DeprecatedFlags
)

 Deprecating this because we "should", but all internal references to these flags were deprecated in 4.21 so hopefully no one is using them anymore! Misc/Compression.h  

static FString GetCompressorDDCSuffix ( FName FormatName
)

 Returns a string which can be used to identify if a format has become out of date Misc/Compression.h  

static uint32 GetCompressorVersion ( FName FormatName
)

 Returns a version number for a specified format Misc/Compression.h  

static bool GetMaximumCompressedSize ( FName InFormatName,
int64& OutMaxCompressedSize,
int64 InUncompressedSizeBytes,
uintptr_t InCompressionData
)

 Thread-safe abstract compression routine to query maximum compressed size that could be made. Misc/Compression.h  

static int32 GetMaximumCompressedSize ( FName FormatName,
int32 UncompressedSize,
ECompressionFlags Flags,
int32 CompressionData
)

 Thunks to the 64 bit version, prefer that as this can only Fatal on error! Misc/Compression.h  

static bool IsFormatValid ( FName FormatName
)

 Checks to see if a format will be usable, so that a fallback can be used Misc/Compression.h  

static bool UncompressMemory ( FName FormatName,
void* UncompressedBuffer,
int64 UncompressedSize,
const void* CompressedBuffer,
int64 CompressedSize,
ECompressionFlags Flags,
uintptr_t CompressionData
)

 Thread-safe abstract decompression routine. Misc/Compression.h  

static bool UncompressMemoryStream ( FName FormatName,
void* UncompressedBuffer,
int64 UncompressedSize,
IMemoryReadStream* Stream,
int64 StreamOffset,
int64 CompressedSize,
ECompressionFlags Flags,
uintptr_t CompressionData
)

 Wraps UncompressMemory to provide access with a IMemoryReadStream interface, attempting to avoid copying in to a contiguous buffer doe decompression if the format supports it. Misc/Compression.h  

static bool VerifyCompressionFlagsValid ( int32 InCompressionFlags
)

 Verifies if the passed in value represents valid compression flags Misc/Compression.h  

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