Getting a fast directory list

[David Lloyd]

I just discovered that Dir$("*.*", 16) does not filter and
return only directory entries. For the time being I added a
filter (GetAttr(FileName$) And 16) = 16, but the code is slow.
A directory list box gets this data in a fraction of the time.

What is the right way to parse directories? Also, I'm going to
want to add a date filter, in case that makes a difference.



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[Tom Hanlin]

As far as BASIC-only methods go, it sounds like you've got it right. In this case,
you can probably do it faster by making a few Windows API calls. FindFirstFile and
FindNextFile will not relieve you of the need to filter the results, but they
return such details as time/date stamps and file attributes as part of a TYPE, so
it's there at your fingers.

If you have PB/CC, see your Samples\Util\FileFind.BAS example. The samples can also
be downloaded from our Downloads area. Or, search the Forums for previous posts on
this subject.

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Tom Hanlin
PowerBASIC Staff

[Borje Hagsten]

Following may be of help, see WIN32_FIND_DATA in winapi32.hlp for
info about file dates.

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' Populate a Listbox with directories
' hWndList is Listbox handle, AbsPath is path to look in, like c:\
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SUB DirsToList(BYVAL hWndList AS LONG, BYVAL AbsPath AS STRING)
  LOCAL hSearch AS LONG, fRes AS LONG, Path AS STRING, arr() AS STRING, dc AS LONG
  LOCAL WFD AS WIN32_FIND_DATA, I AS LONG
 
  IF RIGHT$(AbsPath, 1) <> "\" THEN AbsPath = AbsPath & "\"
  Path = AbsPath
  AbsPath = AbsPath + "*"
 
  hSearch = FindFirstFile(BYVAL STRPTR(AbsPath), WFD) 'Loop through directory
  IF hSearch <> %INVALID_HANDLE_VALUE THEN
     fRes = %TRUE
     DO WHILE fRes
        IF ASC(WFD.cFileName) <> 46 THEN      'No . or ..
           IF (WFD.dwFileAttributes AND 16) = 16 THEN 'dirs only, use "<> 16" for files only..
              AbsPath = TRIM$(WFD.cFileName, CHR$(0))
              REDIM PRESERVE arr(dc)
              arr(dc) = Path + AbsPath  '<- remove Path if you only want actual directory names
              INCR dc
            END IF
        END IF
        fRes = FindNextFile(hSearch, WFD) ' Get next
     LOOP
     fRes = FindClose(hSearch)
  END IF
 
  ARRAY SORT arr(), COLLATE UCASE '<- sort array, if you like/need to
 
  IF hWndList THEN
     CALL SendMessage(hWndList, %LB_RESETCONTENT, 0, 0) 'clear list
     FOR I = 0 TO UBOUND(arr)
        CALL SendMessage(hWndList, %LB_ADDSTRING, 0, BYVAL STRPTR(arr(I)))
     NEXT
  END IF
 
END SUB

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[David Lloyd]

Tom and Borje,

Thank you for your help. I did not see Borje's reply until
after I had solved my problem, but I was amazed at how closely
my final code resembled Borje's code. (My code added the
wildcard function adapted from pbcc's filefind sample code
as Tom suggested, otherwise it was the same with only the
variable names changed.)

David Lloyd



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