passing dynamic string arrays

[Chris Holbrook]

I want to pass an array address to a function which populates the array with up to m rows (max of m is known) of n columns (max of n is not known, though there is a limit to the combined length of all ns in a row). It's easy to pass a one-dimensional string array pointer and populate the array, which takes care of m, but how does one copy the entire array into a string and then extract it again? The nature of the data precludes the use of substring delimiters, and because n is unknown to the calling procedure it is not possible to REDIM the passed array to fit.

Looking at GET# and PUT# help, it appears possible that the string could be stored in one of two different formats. Also, do dynamic string arrays always occupy contiguous storage? If so, just a length function would be enough. But LEN() does not appear to work either with arrays or with string pointers.

Sure I've read something on this but I can't find it again, about time the topical index facility was added to these forums!

[Michael Mattias]

??

Why not just pass the entire array and resize it in the load function?

FUNCTION Populate (S() AS STRING) AS LONG

   REDIM S (m,n) 
   Populate...

END FUNCTION

...
    REDIM X(0,0) AS STRING
    CALL  Populate (X()) 
    nRow =    UBOUND (X,1) + 1     ' assuming populated from (0,0) 
    nColumn = UBOUND (X,2) + 1

???

Yes, string arrays like all arrays in memory use contiguous memory for the string handles (32-bit values), although the string data itself might be 'anywhere'

When a string array is saved to disk, it's not saved that way; that's a whole 'nother thing.

Both memory and disk storage formats are described in the help file.

LEN() works just fine with arrays and STRING PTRs. Show failing code.

[Chris Holbrook]

Why not just pass the entire array and resize it in the load function?

You mean just like this? It seems to work...

#COMPILE EXE
#DIM ALL
#INCLUDE "WIN32API.INC"
%IDD_DIALOG1  =  101
%IDC_LISTBOX1 = 1001
%IDC_LABEL1   = 1002
'------------------------------------------------------------------
SUB poparray( s() AS STRING)
    LOCAL i, j, n, m AS LONG

    n = RND(1,10)
    m = RND(3, 9)
    
    REDIM s( 0 TO m, 0 TO n) AS STRING
    FOR i = 0 TO m
        FOR j = 0 TO n
            s(i, j) = STR$(i* (j^2) + j)
        NEXT
        s(i,0) = STR$(i)
    NEXT
END SUB
'------------------------------------------------------------------
CALLBACK FUNCTION ShowDIALOG1Proc()
    LOCAL i, j AS LONG
    LOCAL sarray() AS STRING
    LOCAL s AS STRING

    SELECT CASE AS LONG CBMSG
        CASE %WM_INITDIALOG
            GOSUB test
        CASE %WM_COMMAND
            SELECT CASE AS LONG CBCTL
                CASE %IDC_LISTBOX1
                    RANDOMIZE
                    LISTBOX RESET CBHNDL, %IDC_LISTBOX1
                    GOSUB test
            END SELECT
    END SELECT
    EXIT FUNCTION
test:
    REDIM sarray(0 TO 0) AS STRING
    poparray( sarray())
    FOR i = LBOUND(sarray, 1) TO UBOUND(sarray, 1)
        s = ""
        FOR j = LBOUND(sarray, 2) TO UBOUND(sarray, 2)
            s = s + "," + sarray(i, j)
        NEXT
        LISTBOX ADD CBHNDL, %idc_listbox1, MID$(s, 2)
    NEXT
    RETURN
END FUNCTION
'------------------------------------------------------------------

FUNCTION ShowDIALOG1(BYVAL hParent AS DWORD) AS LONG
    LOCAL lRslt AS LONG
    LOCAL hDlg  AS DWORD

    DIALOG NEW hParent, "pop string array of unknown dimensions", 155, 116, 270, 140, %WS_POPUP OR %WS_BORDER OR %WS_DLGFRAME OR _
        %WS_SYSMENU OR %WS_CLIPSIBLINGS OR %WS_VISIBLE OR %DS_MODALFRAME OR %DS_3DLOOK OR %DS_NOFAILCREATE OR %DS_SETFONT, _
        %WS_EX_CONTROLPARENT OR %WS_EX_LEFT OR %WS_EX_LTRREADING OR %WS_EX_RIGHTSCROLLBAR, TO hDlg
    CONTROL ADD LISTBOX, hDlg, %IDC_LISTBOX1, , 5, 5, 260, 110, %WS_CHILD OR %WS_VISIBLE OR %WS_TABSTOP OR %WS_VSCROLL OR _
        %LBS_NOTIFY, %WS_EX_CLIENTEDGE OR %WS_EX_LEFT OR %WS_EX_LTRREADING OR %WS_EX_RIGHTSCROLLBAR
    CONTROL ADD LABEL, hDlg, %IDC_LABEL1, "click on the listbox data to refresh", 5, 118, 160, 15
    DIALOG SHOW MODAL hDlg, CALL ShowDIALOG1Proc TO lRslt
    FUNCTION = lRslt
END FUNCTION
'===================================================
FUNCTION PBMAIN()
    ShowDIALOG1 %HWND_DESKTOP
END FUNCTION

[Michael Mattias]

I've been doing that literally for years for "load" functions. It makes it really easy to change "how much" stuff gets loaded.

Also, it's how I discovered the incompatibility between PB 6x- and 7x+ array descriptors. My 7x program failed to load something using a function from a 6x DLL.

MCM