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[BUG/PRB.] VFP 9.0 FIX - GRID.OPTIMIZE PROPERTY
January 2024
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CCB
1. BUG:
In vfp9, we can set the Grid.Optimize property to true (.T.) for the Grid control uses Rushmore optimization,
but sometimes VFP will crash.
The bug was reported by Jurgen Wondzinski (wOOdy).
2. CAUSE:
There are some BUGs in the following code.
3. RESOLUTION:
We can write some code to fix the BUG.
Fun51b751 :: ; proc near
push ebp ;0x0051b751 : 55
mov ebp , esp ;0x0051b752 : 8bec
sub esp , 038h ;0x0051b754 : 83ec38
push ebx ;0x0051b757 : 53
push esi ;0x0051b758 : 56
mov esi , ecx ;0x0051b759 : 8bf1
mov eax , dword ptr [esi] ;0x0051b75b : 8b06
mov ecx , dword ptr [ eax + 12 ] ;0x0051b75d : 8b480c
cmp ecx , edx ;0x0051b760 : 3bca
push edi ;0x0051b762 : 57
mov dword ptr [ ebp - 8 ] , esi ;0x0051b763 : 8975f8
jne Label51b774 ;0x0051b766 : 750c
mov edi , dword ptr [ ebp + 8 ] ;0x0051b768 : 8b7d08
and edi , 01h ;0x0051b76b : 83e701
shl edi , 02h ;0x0051b76e : c1e702
or dword ptr [ eax + 92 ] , edi ;0x0051b771 : 09785c
Label51b774 ::
mov eax , dword ptr [ Data9370f8 ] ;0x0051b774 : a1f8709300
mov eax , dword ptr [eax] ;0x0051b779 : 8b00
cmp dword ptr [ eax + 32 ] , edx ;0x0051b77b : 395020
jne Label51b7e2 ;0x0051b77e : 7562
cmp ecx , edx ;0x0051b780 : 3bca
jne Label51b7e2 ;0x0051b782 : 755e
mov eax , dword ptr [ Data9393ac ] ;0x0051b784 : a1ac939300
mov dword ptr [ ebp - 12 ] , eax ;0x0051b789 : 8945f4
mov eax , esi ;0x0051b78c : 8bc6
call Fun519640 ;0x0051b78e : e8addeffff
mov ebx , dword ptr [esi] ;0x0051b793 : 8b1e
pushd 0Ah ;0x0051b795 : 6a0a
lea esi , dword ptr [ ebx + 067Ch ] ;0x0051b797 : 8db37c060000
pop ecx ;0x0051b79d : 59
lea edi , dword ptr [ ebp - 52 ] ;0x0051b79e : 8d7dcc
rep movsd ;0x0051b7a1 : f3a5
mov dword ptr [ ebp + 8 ] , eax ;0x0051b7a3 : 894508
mov eax , dword ptr [ ebp - 36 ] ;0x0051b7a6 : 8b45dc
xor edi , edi ;0x0051b7a9 : 33ff
cmp eax , edi ;0x0051b7ab : 3bc7
jne Label56b765 ;0x0051b7ad : 0f85b2ff0400
test byte ptr [ ebx + 99 ] , 02h ;0x0051b7b3 : f6436302
jne Label56b773 ;0x0051b7b7 : 0f85b6ff0400
Label51b7bd ::
;
; -------------------------------------------------
; VFP 9.0 FIX - GRID.OPTIMIZE PROPERTY
; September 2015
; -------------------------------------------------
; CCB
;
; If we set the Grid.Optimize property to true (.T.), sometimes VFP will crash.
;
; 2015/9/20, by ccb
;
cmp dword ptr vfpa_sys9044_data,00h
je Label51b7be
mov eax , dword ptr [ ebp - 36 ]
test eax,eax
je Label51b7bf
push eax
sub eax,08h
push 08h
push eax
call vfpa_isbadreadptr
test eax,eax
pop eax
jne Label51b7bf
push eax
sub eax,08h
push dword ptr [eax+04h]
push eax
call vfpa_isbadreadptr
test eax,eax
pop eax
jne Label51b7bf
jmp Label51b7be
Label51b7bf ::
mov dword ptr [ ebp - 36 ] , 00h
Label51b7be ::
mov eax , dword ptr [ ebp - 36 ] ;0x0051b7bd : 8b45dc
mov esi , dword ptr [ ebp - 8 ] ;0x0051b7c0 : 8b75f8
mov dword ptr [ ebx + 068Ch ] , eax ;0x0051b7c3 : 89838c060000
mov eax , dword ptr [ ebp - 40 ] ;0x0051b7c9 : 8b45d8
mov dword ptr [ ebx + 0688h ] , eax ;0x0051b7cc : 898388060000
mov eax , dword ptr [ ebp + 8 ] ;0x0051b7d2 : 8b4508
call Fun519661 ;0x0051b7d5 : e887deffff
mov eax , dword ptr [ ebp - 12 ] ;0x0051b7da : 8b45f4
mov dword ptr [ Data9393ac ] , eax ;0x0051b7dd : a3ac939300
Label51b7e2 ::
xor eax , eax ;0x0051b7e2 : 33c0
inc eax ;0x0051b7e4 : 40
lea esp , dword ptr [ ebp - 68 ] ;0x0051b7e5 : 8d65bc
pop edi ;0x0051b7e8 : 5f
pop esi ;0x0051b7e9 : 5e
pop ebx ;0x0051b7ea : 5b
leave ;0x0051b7eb : c9
ret 04h ;0x0051b7ec : c20400
Label56b765 ::
;
; -------------------------------------------------
; VFP 9.0 FIX - GRID.OPTIMIZE PROPERTY
; September 2015
; -------------------------------------------------
; CCB
;
; If we set the Grid.Optimize property to true (.T.), sometimes VFP will crash.
;
; 2015/9/20, by ccb
;
cmp dword ptr vfpa_sys9044_data,00h
je Label56b766
mov eax , dword ptr [ ebp - 36 ]
test eax,eax
je Label56b76a
push eax
sub eax,08h
push 08h
push eax
call vfpa_isbadreadptr
test eax,eax
pop eax
jne Label56b76a
push eax
sub eax,08h
push dword ptr [eax+04h]
push eax
call vfpa_isbadreadptr
test eax,eax
pop eax
jne Label56b76a
Label56b766 ::
call Fun530453 ;0x0056b765 : e8e94cfcff
Label56b76a ::
mov dword ptr [ ebp - 36 ] , edi ;0x0056b76a : 897ddc
mov dword ptr [ ebx + 068Ch ] , edi ;0x0056b76d : 89bb8c060000
Label56b773 ::
mov esi , dword ptr [ ebx + 0120h ] ;0x0056b773 : 8bb320010000
cmp esi , edi ;0x0056b779 : 3bf7
je Label56b7c6 ;0x0056b77b : 7449
xor eax , eax ;0x0056b77d : 33c0
call Fun42c118 ;0x0056b77f : e89409ecff
mov eax , esp ;0x0056b784 : 8bc4
sub eax , dword ptr [ Data9370c4 ] ;0x0056b786 : 2b05c4709300
cmp eax , esi ;0x0056b78c : 3bc6
jle Label56b7a2 ;0x0056b78e : 7e12
mov eax , esi ;0x0056b790 : 8bc6
add eax , 07h ;0x0056b792 : 83c007
and eax , 0FFFFFFF8h ;0x0056b795 : 83e0f8
call Fun42c118 ;0x0056b798 : e87b09ecff
mov dword ptr [ ebp - 48 ] , esp ;0x0056b79d : 8965d0
jmp Label56b7a5 ;0x0056b7a0 : eb03
4. APPLIES TO:
VFP 9.0.0.2412
VFP 9.0.0.3504 (SP1)
VFP 9.0.0.4611 (SP2)
VFP 9.0.0.5015 (SP2)
VFP 9.0.0.5411 (SP2)
VFP 9.0.0.5721 (SP2)
VFP 9.0.0.5815 (SP2)
VFP 9.0.0.6303 (SP2)
VFP 9.0.0.6602 (SP2)
VFP 9.0.0.7423 (SP2)
The bug has been fixed in VFP Advanced.
IMPORTANT NOTE:
If we disable fixing the Grid.Optimize property, and set the Grid.Optimize property to true (.T.) for the Grid control,
sometimes there is the memory access violation exception (exception code 0xC0000005).
If we enable fixing the Grid.Optimize property, and set the Grid.Optimize property to true (.T.) for the Grid control,
there is no the memory access violation exception (exception code 0xC0000005), but sometimes the index file will be corrupted.
Recommend to set the Grid.Optimize property to false (.F.),
there is no the memory access violation exception (exception code 0xC0000005), and the index file will not be corrupted.
5. REFERENCE WEBSITES:
1, baiyujia.com:
http://www.baiyujia.com
http://www.baiyujia.com/vfpdocuments/f_vfp9fix141.asp
2, foxite.com:
http://www.foxite.com/archives/grid-optimize-property-0000346194.htm
3, microsoft.com:
https://social.msdn.microsoft.com/Forums/de-DE/2b5034ee-4bb8-4267-9680-99306408ec64/c0000005absturz-im-grid-mit-optimizet
6. OTHER:
For reference only, there is no guarantees.
Any questions or suggestions, please send me an email at ccb2000@163.com.
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