Hello friends, here is a simple little application to obtain and separate the executable filename and arguments from the command-line. Perhaps the student can be asked to modify the code to handle each argument. (No pain, no gain, right?) :bg ParseCL should work in both Win32 GUI mode (start-->run-->ParseCl.exe [args] [args...]) or in console (CUI) mode. Link with /subsystem:windows to prevent a CUI window from appearing while it executes.
GeneSysRt.inc should be available in the next build.
; ParseCL by Mark Jones 2006 (596n9xz02 AT sneakemail D0T com)
; GeneSys tutorial, separates command-line filename from arguments
include \GeneSys\include\GeneSysRt.inc ; standard compile-time libs
.const
szTitle db "ParseCL",0 ; dialog caption
szFormat db "Executed File: %s",13,10,"Arguments: %s",0
.data?
szFile db MAX_PATH dup(?) ; executed filename
szArgs db 1759 dup(?) ; arguments
szBuff db 2048 dup(?) ; result
.data
.code
start:
push esi ; save esi
push edi ; and edi
cld ; direction flag must be clear
call GetCommandLine ; returns pointer to string
mov esi,eax ; esi = "\file.exe" arg, arg...
lea edi,szFile ; edi = filename buffer
@@: movsb ; byte edi<--esi, both++
cmp byte ptr [esi-1],00h ; was char == null?
jz ready ; if so, done
cmp byte ptr [esi-1],20h ; was last char copied a space?
jnz @B ; loop until space copied
lea edi,szArgs ; edi = arguments
@@: movsb ; copy argument bytes
cmp byte ptr [esi-1],00 ; wait for the copied null
jnz @B ; loop until done
pop edi ; restore edi
pop esi ; and esi
ready:
invoke wsprintf,addr szBuff,addr szFormat,addr szFile,addr szArgs
invoke MessageBox,0,addr szBuff,addr szTitle,MB_OK
invoke ExitProcess,0 ; exit gracefully with errorlevel 0
end start
Mark, thanks for sending the algo. A question, why do you need 1787 bytes for the argumets buffer? Is it the result of a calculation?
Oh that is a little bug. It should be 2048 - MAX_PATH - szArgs - (bytes added by szFormat) - 1 so that all the text will fit into szBuff with one null left untouched. I doubt anyone will try to pass a string of arguments that long, but it should work if they do. :U
I'm wondering why to preserve esi and edi registers in non CALLBACK proc :wink
In that relation I can't find any answer of the question "Why preserve registers ?"
here: http://x86assembly.codegurus.org/Registers.html