//0x20 bytes (sizeof)
struct _MAPPED_FILE_SEGMENT
{
    struct _CONTROL_AREA* ControlArea;                                      //0x0
    ULONG TotalNumberOfPtes;                                                //0x4
    struct _SEGMENT_FLAGS SegmentFlags;                                     //0x8
    ULONG NumberOfCommittedPages;                                           //0xc
    ULONGLONG SizeOfSegment;                                                //0x10
    union
    {
        struct _MMEXTEND_INFO* ExtendInfo;                                  //0x18
        VOID* BasedAddress;                                                 //0x18
    };
    struct _EX_PUSH_LOCK SegmentLock;                                       //0x1c
};