[DUG] Reading binary data as date/time from registry

[Jan Bakuwel]

Hi all,

It took a while but I found the solution. Here's the code, perhaps it's
useful to someone else.
Many thanks for the suggestions.

Jan


function RegistryBinaryToDateTime (const Registry: TRegistry; const
sKey, sValue: string): TDateTime;
const
  SECS_IN_DAY = 86400;
  BILLS_CONSTANT = 10000000;
type
  TbinData = array[0..7] of byte;
 
  function u64(binData: TbinData): uint64;
  var i: integer; m: uint64;
  begin
    Result := 0; m := 1;
    for i := Low(binData) to High(binData) do
    begin
      Result := m * binData[i] + Result;
      m := m * 256;
    end;
  end;
 
var
  uDays, uSeconds: uint64;
  binData: TbinData;
 
begin
  if not Assigned(Registry) 
  then raise Exception.Create('Please open the registry before calling
this function.');
  with Registry do
  begin
    if OpenKey (sKey, False) then                       // Open the
registry key
    begin
      ReadBinaryData(sValue, binData, 8);               // Read value
from the registry
      Result := EncodeDateTime(1601, 1, 1, 0, 0, 0, 0); // Set the epoch
according to Bill
      uSeconds := u64(binData) div BILLS_CONSTANT;      // Apply Bill's
constant (no, don't ask)
      uDays := uSeconds div SECS_IN_DAY;                // Calculate days
      uSeconds := uSeconds - (uDays * SECS_IN_DAY);     // and seconds
      Result := IncDay (Result, uDays);                 // as
(apparently??) we can't just do IncSecond
      Result := IncSecond (Result, uSeconds);           // so first add
the days, then the remainder of the seconds
      CloseKey;                                         // Close the
registry key
    end;
  end;
end;