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[ENHANCED] VFP 9.0 FIX - THE MAXIMUM NUMBER OF CHARACTERS FOR THE FGETS() FUNCTION
January 2024
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CCB
1. BUG:
In vfp9 (and vfp6, vfp7, vfp8), the maximum number of characters for the FGETS() function is 0x2000 (8192),
now the maximum number of characters for the FGETS() function can be set to 0x2000 (8192) to 0x0FFFFFE0 (268435424).
2. CAUSE:
There are some BUGs in the following code.
3. RESOLUTION:
We can write some code to fix the BUG.
Fun74beb6 :: ; proc near
push ebp ;0x0074beb6 : 55
mov ebp , esp ;0x0074beb7 : 8bec
sub esp , 074h ;0x0074beb9 : 83ec74
push ebx ;0x0074bebc : 53
push esi ;0x0074bebd : 56
push edi ;0x0074bebe : 57
xor esi , esi ;0x0074bebf : 33f6
mov edi , 01h ;0x0074bec1 : bf01000000
mov dword ptr [ ebp - 20 ] , esi ;0x0074bec6 : 8975ec
mov byte ptr [ ebp - 4 ] , 0Dh ;0x0074bec9 : c645fc0d
mov byte ptr [ ebp - 3 ] , 0Ah ;0x0074becd : c645fd0a
mov dword ptr [ ebp - 8 ] , 0FEh ;0x0074bed1 : c745f8fe000000
mov dword ptr [ ebp - 16 ] , edi ;0x0074bed8 : 897df0
mov dword ptr [ ebp - 12 ] , esi ;0x0074bedb : 8975f4
call Fun420d8c ;0x0074bede : e8a94ecdff
mov ebx , eax ;0x0074bee3 : 8bd8
cmp dword ptr [ Data936f1c ] , edi ;0x0074bee5 : 393d1c6f9300
mov dword ptr [ ebp - 28 ] , ebx ;0x0074beeb : 895de4
jle Label74bf82 ;0x0074beee : 0f8e8e000000
lea edi , dword ptr [ ebx + 44 ] ;0x0074bef4 : 8d7b2c
call Fun529a6e ;0x0074bef7 : e872dbddff
cmp byte ptr [edi] , 049h ;0x0074befc : 803f49
mov eax , dword ptr [ ebp + 8 ] ;0x0074beff : 8b4508
jne Label74bf3d ;0x0074bf02 : 7539
cmp eax , esi ;0x0074bf04 : 3bc6
;
; ---------------------------------------------------------------------------------
; VFP 9.0 FIX - THE MAXIMUM NUMBER OF CHARACTERS FOR THE FGETS() FUNCTION
; July 2021
; ---------------------------------------------------------------------------------
; CCB
;
; The maximum number of characters for the FGETS() function.
;
; 2021/7/18, by ccb
;
; mov eax , 02000h ;0x0074bf06 : b800200000
mov eax , dword ptr vfpa_sys9063_data ;0x0074bf06 : b800200000
jne Label74bf12 ;0x0074bf0b : 7505
mov eax , dword ptr [ Data936f20 ] ;0x0074bf0d : a1206f9300
Label74bf12 ::
pushd 0385h ;0x0074bf12 : 6885030000
push eax ;0x0074bf17 : 50
push esi ;0x0074bf18 : 56
mov eax , edi ;0x0074bf19 : 8bc7
call Fun529bc5 ;0x0074bf1b : e8a5dcddff
mov edx , dword ptr [ Data936f1c ] ;0x0074bf20 : 8b151c6f9300
mov dword ptr [ ebp - 8 ] , eax ;0x0074bf26 : 8945f8
xor eax , eax ;0x0074bf29 : 33c0
cmp edx , 02h ;0x0074bf2b : 83fa02
setg al ;0x0074bf2e : 0f9fc0
cmp eax , esi ;0x0074bf31 : 3bc6
mov dword ptr [ ebp - 12 ] , eax ;0x0074bf33 : 8945f4
je Label74bf82 ;0x0074bf36 : 744a
add edi , 02Ch ;0x0074bf38 : 83c72c
jmp Label74bf4d ;0x0074bf3b : eb10
Label74bf3d ::
cmp eax , esi ;0x0074bf3d : 3bc6
je Label74bfea ;0x0074bf3f : 0f84a5000000
mov eax , 01h ;0x0074bf45 : b801000000
mov dword ptr [ ebp - 12 ] , eax ;0x0074bf4a : 8945f4
Label74bf4d ::
cmp eax , esi ;0x0074bf4d : 3bc6
je Label74bf82 ;0x0074bf4f : 7431
mov eax , edi ;0x0074bf51 : 8bc7
call Fun42371d ;0x0074bf53 : e8c577cdff
mov eax , dword ptr [ edi + 8 ] ;0x0074bf58 : 8b4708
cmp eax , 02h ;0x0074bf5b : 83f802
jbe Label74bf65 ;0x0074bf5e : 7605
mov eax , 02h ;0x0074bf60 : b802000000
Label74bf65 ::
mov ecx , eax ;0x0074bf65 : 8bc8
mov edx , ecx ;0x0074bf67 : 8bd1
shr ecx , 02h ;0x0074bf69 : c1e902
mov dword ptr [ ebp - 16 ] , eax ;0x0074bf6c : 8945f0
mov eax , dword ptr [ edi + 32 ] ;0x0074bf6f : 8b4720
mov esi , dword ptr [eax] ;0x0074bf72 : 8b30
lea edi , dword ptr [ ebp - 4 ] ;0x0074bf74 : 8d7dfc
rep movsd ;0x0074bf77 : f3a5
mov ecx , edx ;0x0074bf79 : 8bca
and ecx , 03h ;0x0074bf7b : 83e103
rep movsb ;0x0074bf7e : f3a4
xor esi , esi ;0x0074bf80 : 33f6
Label74bf82 ::
mov edi , ebx ;0x0074bf82 : 8bfb
mov word ptr [ Data93bc88 ] , si ;0x0074bf84 : 66893588bc9300
call Fun529a6e ;0x0074bf8b : e8dedaddff
cmp byte ptr [ebx] , 049h ;0x0074bf90 : 803b49
mov esi , dword ptr [ ebx + 12 ] ;0x0074bf93 : 8b730c
jne Label74bfa2 ;0x0074bf96 : 750a
push esi ;0x0074bf98 : 56
call Fun45340a ;0x0074bf99 : e86c74d0ff
test eax , eax ;0x0074bf9e : 85c0
jne Label74bfae ;0x0074bfa0 : 750c
Label74bfa2 ::
or esi , 0FFFFFFFFh ;0x0074bfa2 : 83ceff
mov word ptr [ Data93bc88 ] , 06h ;0x0074bfa5 : 66c70588bc93000600
Label74bfae ::
cmp esi , 0FFFFFFFFh ;0x0074bfae : 83feff
mov dword ptr [ ebp - 32 ] , esi ;0x0074bfb1 : 8975e0
je Label74c026 ;0x0074bfb4 : 7470
mov eax , esi ;0x0074bfb6 : 8bc6
call Fun68518e ;0x0074bfb8 : e8d191f3ff
test eax , eax ;0x0074bfbd : 85c0
jne Label74c026 ;0x0074bfbf : 7565
mov edi , dword ptr [ ebp - 8 ] ;0x0074bfc1 : 8b7df8
cmp edi , 0FFFFh ;0x0074bfc4 : 81ffffff0000
jbe Label74c029 ;0x0074bfca : 765d
test byte ptr [ Data936f10 ] , 01h ;0x0074bfcc : f605106f930001
je Label74c01c ;0x0074bfd3 : 7447
mov eax , dword ptr [ Data936f14 ] ;0x0074bfd5 : a1146f9300
test eax , eax ;0x0074bfda : 85c0
jne Label74c029 ;0x0074bfdc : 754b
mov dword ptr [ Data936f14 ] , 0385h ;0x0074bfde : c705146f930085030000
jmp Label74c029 ;0x0074bfe8 : eb3f
Label74bfea ::
test byte ptr [ Data936f10 ] , 01h ;0x0074bfea : f605106f930001
je Label74c012 ;0x0074bff1 : 741f
cmp dword ptr [ Data936f14 ] , esi ;0x0074bff3 : 3935146f9300
jne Label74c199 ;0x0074bff9 : 0f859a010000
mov dword ptr [ Data936f14 ] , 0385h ;0x0074bfff : c705146f930085030000
pop edi ;0x0074c009 : 5f
pop esi ;0x0074c00a : 5e
pop ebx ;0x0074c00b : 5b
mov esp , ebp ;0x0074c00c : 8be5
pop ebp ;0x0074c00e : 5d
ret 04h ;0x0074c00f : c20400
4. APPLIES TO:
VFP 6.0.8167.0
VFP 6.0.8961.0 (SP5)
VFP 7.0.0.9262
VFP 7.0.0.9465 (SP1)
VFP 8.0.0.2521
VFP 8.0.0.3117 (SP1)
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.
5. REFERENCE WEBSITES:
1, baiyujia.com:
http://www.baiyujia.com
http://www.baiyujia.com/vfpdocuments/f_vfp9fix182.asp
http://www.baiyujia.com/vfpdocuments/f_vfp9fix170.asp
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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