struct COMPRESSED_DATA_INFO

typedef struct _COMPRESSED_DATA_INFO
{
     WORD CompressionFormatAndEngine;
     UCHAR CompressionUnitShift;
     UCHAR ChunkShift;
     UCHAR ClusterShift;
     UCHAR Reserved;
     WORD NumberOfChunks;
     ULONG CompressedChunkSizes[1];
} COMPRESSED_DATA_INFO, *PCOMPRESSED_DATA_INFO;

Windows Vista Kernel Structures