FILETIME<> to SYSTEMTIME<>

[Mark Jones]

Hi. I'm a bit baffled by some apparent conversion anomalies between these two. Long story short I thought that a great way of protecting my app would be for it to read it's own file-modified date and time, and compare that with a filetime value written to itself after compilation. This is tricky but it works! However, during testing I ran into a strange issue. I converted the filetime into a system time and tried displaying it. The result is wrong and I can't figure out why. Here is the relevant code:

Code Select Expand


.data?
pFiletime  FILETIME<> ; contains any filetime data, see below
pSystemTime SYSTEMTIME<>

.data
szTmp db 64 dup(0) ; result buffer
szCaption db "Converted FileTime:",0

.code
; for testing, lets just make pFileTime a known date/time
; 000000: 74 85 C9 27 BA 1B C5 01
mov pFileTime.dwHighDateTime, 01C51BBAh   ; 2005/02/25
mov pFileTime.dwLowDateTime, 27C98574h   ; 11:17:59pm

    Invoke FileTimeToSystemTime, Addr pFileTime, Addr pSystemTime

    mov eax,0
    movsx eax, pSystemTime.wMinute ; all are word values
    push eax
    movsx eax, pSystemTime.wHour
    push eax
    movsx eax, pSystemTime.wDay
    push eax
    movsx eax, pSystemTime.wMonth
    push eax
    movsx eax, pSystemTime.wYear
    push eax
   
szText szTimeFormat, "%04u/%02u/%02u, %02u:%02u",0 ; 2005/02/25, 23:17
    push offset szTimeFormat
    lea eax, szTmp
    push eax
    call wsprintf   ; line might be too long to INVOKE

    invoke MessageBox,0,addr szCaption,addr szTmp,MB_OK ; display incorrect!


What happens is the correct year, month, and minute is displayed, but the day is always +1 and the hour is always 04. Printing the word values pSystemTime.wDay and pSystemTime.wHour also shows the same values. Why are these always incorrect? Thanks for any insight.

[Petroizki]

Nothing wrong there.

BUT, the time you have given is in GMT time, you must use FileTimeToLocalFileTime to get it in your machine time. :eek

Code Select Expand


.data?
pLocalFileTime FILETIME <?>
...
.code
invoke FileTimeToLocalFileTime, ADDR pFileTime, ADDR pLocalFileTime
invoke FileTimeToSystemTime, ADDR pLocalFileTime, ADDR pSystemTime



confusing, isn't it..  :lol

[Mark Jones]

 ..Omg, I must be dumb! :lol :red

Thanks for the well-needed eye-opening. :U