FILE_PROVIDER_EXTERNAL_INFO_V1 structure (ntifs.h)

The FILE_PROVIDER_EXTERNAL_INFO_V1 structure defines metadata specific to files provided by WOF_PROVIDER_FILE. This provider gives efficient compression for data that won't be modified, such as executable files. If the file is opened for write access, the file will be transparently decompressed.

Syntax

typedef struct _FILE_PROVIDER_EXTERNAL_INFO_V1 {
  ULONG Version;
  ULONG Algorithm;
  ULONG Flags;
} FILE_PROVIDER_EXTERNAL_INFO_V1, *PFILE_PROVIDER_EXTERNAL_INFO_V1;

Members

Version

The version of the provider to use. Specify FILE_PROVIDER_CURRENT_VERSION.

Algorithm

Specifies the compression algorithm that is used to compress this file. Currently defined algorithms are:

Algorithm	Description
FILE_PROVIDER_COMPRESSION_XPRESS4K	The data for the file should be compressed in 4kb chunks with the XPress algorithm. This algorithm is designed to be computationally lightweight, and provides for rapid access to data.
FILE_PROVIDER_COMPRESSION_LZX	The data for the file should be compressed in 32kb chunks with the LZX algorithm. This algorithm is designed to be highly compact, and provides for small footprint for infrequently accessed data.
FILE_PROVIDER_COMPRESSION_XPRESS8K	The data for the file should be compressed in 8kb chunks with the XPress algorithm.
FILE_PROVIDER_COMPRESSION_XPRESS16K	The data for the file should be compressed in 16kb chunks with the XPress algorithm.

Flags

Specifies flags for the operation. Reserved for future use, should be 0.

Requirements

Requirement	Value
Minimum supported client	Windows 10
Header	ntifs.h (include Windows.h, WinIoCtl.h, Ntifs.h, Windows.h, WinIoCtl.h, Ntifs.h)

See also

FILE_PROVIDER_EXTERNAL_INFO_V0