typedef struct _HEAP_SEGMENT
{
    HEAP_ENTRY Entry;
    unsigned long SegmentSignature;
    unsigned long SegmentFlags;
    LIST_ENTRY SegmentListEntry;
    HEAP *Heap;
    void *BaseAddress;
    unsigned long NumberOfPages;
    HEAP_ENTRY *FirstEntry;
    HEAP_ENTRY *LastValidEntry;
    unsigned long NumberOfUnCommittedPages;
    unsigned long NumberOfUnCommittedRanges;
    unsigned short SegmentAllocatorBackTraceIndex;
    unsigned short Reserved;
    LIST_ENTRY UCRSegmentList;
} HEAP_SEGMENT, *PHEAP_SEGMENT;