What's the API to read File Info without opening it?

[dedndave]

thanks for the tip Shantanu   :t

GetFileAttributesEx seems to work on boot.ini, but not pagefile.sys
it even works on C:\   :P

what you could do is use GetFileAttributesEx for speed
if that fails, then use FindFirstFile to verify whether or not the file really exists

typically, when i use GetFileAttributesEx, i am using it on a config file or some other similar data file, though

[frktons]

Probably I'm not going to use these functions on critical
files, but it is good to know anyway that on some files
the functions can fail.

Thanks and Happy Holidays.

[dedndave]

i played with it anyways
the WIN32_FIND_DATA structure is a superset of the WIN32_FILE_ATTRIBUTE_DATA structure
so - the code is pretty simple
while i was at it, i made some more improvements on the parser
i made sure to use LODSB, just for Hutch 

Code Select Expand

C:\>"documents and settings\fileinfo" "c:\pagefile.sys
nFileSize:        000000005F400000h
ftCreationTime:   MON 12-10-2012 0:23:34.390
ftLastAccessTime: TUE 12-25-2012 13:32:44.125
ftLastWriteTime:  TUE 12-25-2012 13:32:44.125

FILE_ATTRIBUTE_HIDDEN
FILE_ATTRIBUTE_SYSTEM
FILE_ATTRIBUTE_ARCHIVE

the reason i spent time on this is i will use the parse code for future projects
and - it gave me a break from my "big" project - back to that tomorrow   :P

[sinsi]

For a test of the relative speeds of those functions try to get the file information over a network.
This will give you an idea of overhead  :lol:

[dedndave]

that latest version uses FindFirstFile only if GetFileAttributesEx fails

really, you have to tailor your code for the specific application, as always

[frktons]

that latest version uses FindFirstFile only if GetFileAttributesEx fails

really, you have to tailor your code for the specific application, as always

Well done, Dave :t

[jj2007]

FFF finds the *.sys files. As to speed, FindFirstFile is a bit slower because, as the name says, it first has to find the file that matches e.g. *.doc - and that costs time. I have difficulties to construct a real life case where the speed difference matters, i.e. where you have already a complete list of 100,000 files and you still need further info...

include \masm32\MasmBasic\MasmBasic.inc        ; download
        Init        ; ### show files in C:\* ###
        GfNoRecurse=1        ; root only
        GetFiles C:\*
        xchg eax, ecx
        Print "Files in the root:"
        .Repeat
                PrintLine Files$(ecx)
                dec ecx
        .Until Sign?
        Inkey
        Exit
end start

Files in the root:
C:\pagefile.sys
C:\ntldr
C:\NTDETECT.COM
C:\MSDOS.SYS
C:\IO.SYS
C:\install.ini
C:\hiberfil.sys
C:\globdata.ini
C:\CONFIG.SYS
C:\Bootfont.bin
C:\boot.ini
C:\AUTOEXEC.BAT

[frktons]

FFF finds the *.sys files. As to speed, FindFirstFile is a bit slower
because, as the name says, it first has to find the file that
matches e.g. *.doc - and that costs time. I have difficulties
to construct a real life case where the speed difference matters,
i.e. where you have already a complete list of 100,000 files and
you still need further info...

Thanks Jochen for the explanation.

In this case, and for a rare coincidence, I'm not looking
for the fastest API, but just for the suitable ones.