search a buffer for a string

[illwill]

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.386
.model flat,stdcall
option casemap:none

include       \masm32\include\kernel32.inc
includelib    \masm32\lib\kernel32.lib
include       \masm32\include\masm32.inc
includelib    \masm32\lib\masm32.lib
include       \masm32\include\shell32.inc
includelib    \masm32\lib\shell32.lib

.data
string    db "user0           whjJGXajAqpRMN  hex:77686a4a4758616a417170524d4e",0ah
          db "test            RY3FETU<notfound>  hex:52593346455455<notfound>",0ah
          db "test3           TY65DDQ<notfound>  hex:52556654165165<notfound>",0ah,0
.code
start:
    invoke StdOut,addr string
    lea esi,string
    mov edi, esi                 ; set pointer to string start
    xor ecx, ecx                 ; reset ecx
    dec ecx                      ; dec wraps ecx to 0xFFFFFFFF, since 'repne scasb' decriments ecx
    mov eax, 0ah                 ; the byte to search for ('\n' newline)
    ;; after this executes [edi] will point to the byte after '\n' is encountered
    repne scasb                  ; decriment ECX and incriment EDI until AL is encountered
    mov byte ptr [edi], 00h      ; terminate the string

    invoke StdOut,esi            ; esi now holds the user0 string     
   ;at this point i want to loop and get the strings of test and test3 to push to StdOut
       
    invoke ExitProcess,0
end start


[illwill]

figured it out   :U

Code Select Expand


.data
string    db "user0           whjJGXajAqpRMN  hex:77686a4a4758616a417170524d4e",0ah
          db "test            RY3FETU<notfound>  hex:52593346455455<notfound>",0ah
          db "test3           TY65DDQ<notfound>  hex:52556654165165<notfound>",0ah,0
.code
start:
    lea esi,string
    mov edi, esi                 ; set pointer to string start
     invoke lstrlen,esi          ;get the length of the string
     mov ecx,eax                 ;store the length in ecx
loops:
    test ecx,ecx                 ; see if the length is 0
    jz done                      ;if it is then were at the end of the string
    mov eax, 0ah                 ; the byte to search for ('\n' newline)
    repne scasb                  ; decriment ECX and incriment EDI until AL is encountered
    mov byte ptr [edi-1], 00h    ; terminate the string right before the \n
    push ecx
    invoke StdOut,esi            ; esi now holds the user0 string so we output it to screen
    pop ecx
    mov esi,edi                  ;store the new string pointer
    jmp loops
done:
    invoke ExitProcess,0
end start