Array sort, array scan.. on udt's ?

[Eddy Van Esch]

I have a number of 'records' consisting of 4 'fields' in memory.
I would like to use the commands 'array sort', 'array scan',
'array insert' and 'array delete'. Question is: is this possible and
what data structure should I use. I could use a UDT-array or 4 separate
arrays (one for every field).
'Array sort' only works on 1 array and 1 tagarray..which leaves 2 arrays
unsorted.
Sorting a udt-array (of 4 fields) seems to work, but scan, delete and
insert didn't work in my small test.
I see 2 ways open:
- eiter write my own sort and insert routines (on arrays or udt's),
- or use a main array on which i use the array sort, together with
a tagarray of pointers that points to a udt-array with the 3
remaining fields (or pointers to 3 separate arrays).

Anybody any suggestion?

Kind regards
Eddy



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[Bern Ertl]

Eddy,

ARRAY SCAN & ARRAY SORT have a [, FROM start TO end] option which
allows you to specify the byte positions of the UDT field which you
want to sort/scan.

I've been able to use ARRAY INSERT & ARRAY DELETE with UDT arrays.
Be careful with ARRAY INSERT and UDT arrays though. There is a known
glitch with UDT's which have a LEN MOD 4 <> 0. If your UDT is an
"odd" size, you should pad the UDT with an extra BYTE at the end.



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Bernard Ertl

[Lance Edmonds]

Or use DWORD alignment. Note that this issue will be addressed in the next update to the compiler.



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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Eddy Van Esch]

Thanks for the tip, Bern!
I will try that!!


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[Eddy Van Esch]

Originally posted by Bern Ertl:
Eddy,

ARRAY SCAN & ARRAY SORT have a [, FROM start TO end] option which
allows you to specify the byte positions of the UDT field which you
want to sort/scan.

I've been able to use ARRAY INSERT & ARRAY DELETE with UDT arrays.
Be careful with ARRAY INSERT and UDT arrays though. There is a known
glitch with UDT's which have a LEN MOD 4 <> 0. If your UDT is an
"odd" size, you should pad the UDT with an extra BYTE at the end.

Bern,
I tried it. Array sort, scan and delete work, but array insert does not.
After inserting, I can only read the array elements lower than the position
where the new element was inserted.
My test-UDT was:

Type UDTtype
f1 as string*8
f2 as string*4
end type
dim test(5) as UDTtype
dim ins as UDTtype

array insert test(3) for 2, ins

After this I can only read test(1) and test(2)

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[Bern Ertl]

Could you post the complete example?



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Bernard Ertl

[Eddy Van Esch]

Sorry that I couldn't reply earlier, but here is some code which
demonstrates my problem: Array sort, scan and delete work but
'array insert' produces strange results:
I hope the code is readable cause I don't know how to preserve
the indenting...

'Demo of problem with 'array insert' on an array of UDT's,
'Array scan, sort and delete (of a UDT) seems to work.
#COMPILE EXE
#REGISTER NONE
#DIM ALL
#INCLUDE "win32api.inc"
#INCLUDE "commctrl.inc"
#INCLUDE "COMDLG32.INC"

TYPE testUDT
    f1  AS STRING * 8
    f2  AS STRING * 4
END TYPE

FUNCTION PBMAIN
    LOCAL hMainForm&, Style&
    Style& = %WS_POPUP OR %DS_MODALFRAME OR %WS_CAPTION OR %WS_MINIMIZEBOX OR %WS_SYSMENU OR %DS_CENTER
    DIALOG NEW 0, "UDTtest", 0, 0,  300,  300, Style&, 0  TO hMainForm&
    CONTROL ADD TEXTBOX, hMainForm&,  100,  "", 10, 10, 280, 280, _
      %WS_CHILD OR %WS_VISIBLE OR %ES_AUTOHSCROLL OR %ES_MULTILINE OR %ES_WANTRETURN OR %ES_AUTOVSCROLL _
      OR %WS_HSCROLL OR %WS_VSCROLL, %WS_EX_CLIENTEDGE

    DIM i       AS LONG
    DIM j       AS LONG
    DIM buffer$
    DIM udt(1:6)  AS testUDT
    DIM SingleUdt AS testUDT
        SingleUdt.f1= "udt-test"
        SingleUdt.f2= "0000"
        udt(1).f1   = "zzzz    "
        udt(1).f2   = "1111"
        udt(2).f1   = "aaaa    "
        udt(2).f2   = "2222"
        udt(3).f1   = "cccc    "
        udt(3).f2   = "3333"
        udt(4).f1   = "bbbb    "
        udt(4).f2   = "4444"
        udt(5) = SingleUdt
        ARRAY SCAN udt(1),FROM 1 TO 8, = "bbbb    ", TO j       '<<<<<<<<<<<<<<<
        FOR i = 1 TO 5
            buffer$=buffer$+ udt(i).f1 + udt(i).f2 + $CRLF
        NEXT i
        buffer$=buffer$+"Result of 'array scan' for 'bbbb'is:"+STR$(j)+ $CRLF + $CRLF

            ARRAY SORT udt(1) FOR 5                             '<<<<<<<<<<<<<<<
            FOR i = 1 TO 5
                buffer$=buffer$+ udt(i).f1 + udt(i).f2 + $CRLF
            NEXT i
            buffer$=buffer$+"Result after 'array sort'"+ $CRLF + $CRLF

        ARRAY DELETE udt(4)                                     '<<<<<<<<<<<<<<<
        FOR i = 1 TO 4
            buffer$=buffer$+ udt(i).f1 + udt(i).f2 + $CRLF
        NEXT i
        buffer$=buffer$+"Result after 'array delete' element 4"+ $CRLF + $CRLF

            buffer$=buffer$+"'array insert' seems to fail:"+ $CRLF
            ARRAY INSERT udt(2) FOR 3, SingleUdt                '<<<<<<<<<<<<<<<
            FOR i = 1 TO 4
                buffer$=buffer$+ udt(i).f1 + udt(i).f2 + $CRLF
            NEXT i
            buffer$=buffer$+"Result after 'array insert'"+ $CRLF + $CRLF

        CONTROL SET TEXT hMainForm&, 100, buffer$
    DIALOG SHOW MODAL hMainForm&
END FUNCTION

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[Bern Ertl]

Eddy, you are another victim of the known glitch about the last
byte getting corrupted. If you will notice, the value that is
actually inserted is missing the last "0" character. Strange,
since your UDT is dword aligned & sized.

Change your type declaration like so:

TYPE testUDT
    f1  AS STRING * 8
    f2  AS STRING * 4
    dummy AS BYTE
END TYPE

and it will work.



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Bernard Ertl

[Eddy Van Esch]

Originally posted by Bern Ertl:
Change your type declaration like so:

TYPE testUDT
    f1  AS STRING * 8
    f2  AS STRING * 4
    dummy AS BYTE
END TYPE

and it will work.

Indeed Bern, it works now!
I thought I was safe because of the 4-byte alignment. Obviously
I thought wrong...
Thanks for the support!
Eddy



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