COMPARISON
CompareUnicodeStrings(
  IN  PUNICODE_STRING Prefix,
  IN  PUNICODE_STRING Name,
  IN  ULONG CaseInsensitiveIndex
  );

Routine Description:

    This routine takes a prefix string and a full name string and determines
    if the prefix string is a proper prefix of the name string (case sensitive)

Arguments:

    Prefix - Supplies the input prefix string

    Name - Supplies the full name input string

    CaseInsensitiveIndex - Indicates the wchar index at which to do a case
        insensitive search.  All characters before the index are searched
        case sensitive and all characters at and after the index are searched

Return Value:

    COMPARISON - returns

        IsLessThan    if Prefix < Name lexicalgraphically,
        IsPrefix      if Prefix is a proper prefix of Name
        IsEqual       if Prefix is equal to Name, and
        IsGreaterThan if Prefix > Name lexicalgraphically