Print Page - Understanding struct/class conversion

Title: Understanding struct/class conversion
Post by: jasonabullard on February 22, 2013, 01:35:29 AM

So I am trying to further understand how to take a C++ struct/class and convert that over to a masm style struct. I understand pretty much all the bits and pieces except how to do this when you have functions within the struct. Do I simply define the proto within the struct and then implement in my asm file? Or should I define the proto outside of the struct and use a typedef ptr to the function and use that as a member of the struct?

Example 1

Code Select


manager_t	typedef ptr	_manager_t

_manager_t STRUCT
	base		c_base		<>
	get_msg	proto stdcall	self:manager_t
_manager_t ENDS

or would I do something like this?

Code Select


manager_t	typedef ptr	_manager_t
get_msg		typedef ptr	_get_msg

_get_msg		proto stdcall	self:manager_t

_manager_t STRUCT
	base		c_base		<>
	getMsg	get_msg		?
_manager_t ENDS

Title: Re: Understanding struct/class conversion
Post by: jj2007 on February 22, 2013, 02:10:27 AM

You could distinguish members, methods and functions. For your inspiration, a few snippets from a project I abandoned some months ago ;-)

ClassCounter = 0
CreateClass MACRO TheName:=<close>, TheProc
CurClassName equ <TheName>
ifb <TheProc>
CurClassProc CATSTR <TheName>, <P>
else
CurClassProc equ <TheProc>
endif
MemString CATSTR <TheName>, <_members:# >
CurClassOff = 0
CurClassMethCt = 0
ifidn <TheName>, <close>
ClassCounter = ClassCounter + 1
endif
ENDM

MemCounter=0
AddMembers MACRO Mems:VARARG
LOCAL colon, sl, sr, is
For arg, <Mems>
colon INSTR <arg>, <:>
if colon
sl SUBSTR <arg>, 1, colon-1
sr SUBSTR <arg>, colon+1
is = 0
colon INSTR sr, <WORD>
is = is + colon
colon INSTR sr, <REAL>
is = is + colon
if is
MemString CATSTR MemString, sl, < >, sr, <?# >
else
MemString CATSTR MemString, sl, < >, sr, < !<!># >
endif
else
MemString CATSTR MemString, <arg>, < dd ?# >
endif
ENDM
ENDM
...
.code

CreateClass whatever
AddMembers rc:RECT, myReal8, mydw, my$, myArray$()
AddFunction getrect(hWin) ; returns something
AddMethod setrect rc=left, top, right, bottom ; no retval
AddMethod moverect rc, dx, dy
CreateClass ; no args means <close>

Title: Re: Understanding struct/class conversion
Post by: qWord on February 22, 2013, 02:12:23 AM

First of all, how the structures exactly build, depends on the compilers, thus you may try to find information specific for your compiler.
Prototypes and typedefs of function pointer can declared anywhere (before their usage). But be warned, there is MASM bug for prototypes: if you use the name of a already declared function (prototype) in any expression that will be expand/evaluate by MASM macro engine, an EXTERN entry will be added to the object file, even if you never use that function.

Also, note that commonly only virtual function will be added as function pointers inside the vTbl - other methods are called by label.

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General => The Campus => Topic started by: jasonabullard on February 22, 2013, 01:35:29 AM