Unicode app path algo.

[hutch--]

Needed this for the current toy, nothing exciting but seems to work OK. The test for the beginning of the buffer is probably redundant but you could just be lucky with some weird configuration that did not have a "\" in the return string from GetModuleFileNAme().

Change,

Code Select Expand


mov WORD PTR [eax+2], 0


To

Code Select Expand


mov WORD PTR [eax], 0


If you don't want the trailing backslash.

Code Select Expand


; ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤

uc_app_path proc

  ; ---------------------------------------------------
  ; return OFFSET of unicode app path with trailing "\"
  ; ---------------------------------------------------
    LOCAL plen :DWORD

    .data?
      uc_path_buffer dw 260 dup (?)
    .code

    mov plen, rv(GetModuleFileNameW,NULL,OFFSET uc_path_buffer,260)

    mov edx, OFFSET uc_path_buffer  ; store beginning in EDX
    mov eax, edx                    ; copy it to EAX
    mov ecx, plen                   ; load path length into ECX
    add ecx, ecx                    ; double it to convert unicode to byte length
    add eax, ecx                    ; add length to OFFSET to get path end

  ; ------------------------------
  ; loop backwards to get last "\"
  ; ------------------------------
  @@:
    sub eax, 2
    cmp WORD PTR [eax], "\"         ; get last "\"
    je @F
    cmp eax, edx                    ; else exit at beginning if no "\"
    jne @B

  @@:
    mov WORD PTR [eax+2], 0         ; terminate leaving trailing "\"
    mov eax, OFFSET uc_path_buffer  ; return the buffer OFFSET
    ret

uc_app_path endp

; ¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤


[jj2007]

23 instead of 34 bytes ;-)

Code Select Expand

    mov edx, OFFSET uc_path_buffer  ; store beginning in EDX
    push edx
    invoke GetModuleFileNameW, NULL, edx, 260
    pop edx
    lea eax, [edx+2*eax]


[hutch--]

 :bg

Plus the 520 byte buffer and the adjustment for trailing backslash or not, who cares. I left MS-DOS behind 15 years ago.