Developer CD Series 1993…ch: Other People's Memory/ADC Developer CD (1993-03) (''Other People's Memory'')_iso/Dev.CD Mar 93.iso/Development Platforms/CSMP Digests/csmp-v1-031.txt

Text File | 1992-11-18 | 42.6 KB | 1,304 lines | [TEXT/MPS ]

C.S.M.P. Digest             Thu, 26 Mar 92       Volume 1 : Issue 31

Today's Topics:

    Pointer arithmatic in Pascal question
    Code modules in a program - how to implement?
    How do you write an MDEF that handles scrolling?
    Select Directory dialog
    Where's that code frag that finds the app file ?


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-------------------------------------------------------

From: [e-mail]
Subject: Pointer arithmatic in Pascal question
Date: 27 Jan 92 11:17:14 GMT
Organization: National Research Council

Hi, I usually program in C where pointer arithmatic is widely used. Now, I
need a variable 2D array of integers. In C, I would allocate a 1D array and
use pointer arithmatic to acces the array as a 2D array. Can you do a similar
thing in Pascal?

Thanks in advance,

Rodrigo



- -------------------------

From: [e-mail]
Subject:  Pointer arithmatic in Pascal question
Date: 29 Jan 92 04:42:20 GMT
Organization: Wright State University

In article <[e-mail]>, [e-mail] writes:
> Hi, I usually program in C where pointer arithmatic is widely used. Now, I
> need a variable 2D array of integers. In C, I would allocate a 1D array and
> use pointer arithmatic to acces the array as a 2D array. Can you do a similar
> thing in Pascal?

Depending on the nature of your data, Pascal may provide more elegant
solutions, but pointer arithmetic works fine in Pascal. To avaiod heap
fragmentation, allocate space with Newhandle, call MoveHHi and HLock it.
Call StripAddress on the handle's master pointer and use that as the base of
the array. Calling ord() on a pointer renders a LongInt, and calling pointer()
on a LongInt is assignment compatible with any pointer type.

type IntPtr = ^Integer;
const xDim = columns-1; yDim = rows-1;
var h: Handle; p: IntPtr;
...
h:= NewHandle(xDim*yDim*2);
if h <> nil then
  begin
    MoveHHi(h);
    HLock(h);
    p:= IntPtr(StripAddress(h^))
  end
else p:= nil;
...
procedure SetArray(p:IntPtr; x,y,i:Integer; {p^[x,y]:=i}
begin
  p:= IntPtr(ord(p) + y*xDim*2 + x*2); {or however you want to base the array}
  p^:= i
end;
...
function GetArray(p:IntPtr; x,y:Integer):Integer;
begin
  p:= IntPtr(ord(p) + y*xDim*2 + x*2); {or however you want to base the array}
  GetArray:= p^
end;

Range checking is left as an exercise. Hope this helps.

o----------------------------------------------------------------------------o
| John B. Matthews, [e-mail], disclaimer:= myViews <> WSU |
| "I'm a commensal .sig virus, indistinguishable from an ordinary organelle."|
o----------------------------------------------------------------------------o



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Pointer arithmatic in Pascal question
Date: 30 Jan 92 22:52:28 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] writes:
>> Hi, I usually program in C where pointer arithmatic is widely used. Now, I
>> need a variable 2D array of integers. In C, I would allocate a 1D array and
>> use pointer arithmatic to acces the array as a 2D array. Can you do a similar
>> thing in Pascal?
>
>Depending on the nature of your data, Pascal may provide more elegant
>solutions, but pointer arithmetic works fine in Pascal. To avaiod heap
>fragmentation, allocate space with Newhandle, call MoveHHi and HLock it.
>Call StripAddress on the handle's master pointer and use that as the base of
>the array. Calling ord() on a pointer renders a LongInt, and calling pointer()
>on a LongInt is assignment compatible with any pointer type.

I'd suggest taking a little different approach the one described above.
Given the original poster's needs, there should be no need to move the
handle high in the heap, lock it, or call StripAddress on the master
pointer. On the other hand, there are several reason why you shouldn't
call those routines. Instead, assuming an array of integers, use
something like the following:

TYPE
    IntArray = ARRAY [0..0] OF INTEGER;    { actually variable sized }
    IntArrayPtr = ^IntArray;
    IntArrayHdl = ^IntArrayPtr;

VAR
    myArray: IntArrayHdl;

BEGIN
    myArray = IntArrayHdl(NewHandle(someSize));
    { now initialize all elements to one. }
    for i := 0 to width do begin
        for j := 0 to height do begin
        {$PUSH} {$R-} {turn off range checking}
        myArray^^[j*width+i] := 1;
        {$POP} {restore previsous settings}
        end;
    end;
END.

This is just off the top of my head, so I hope I'm not too far off.

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



- -------------------------

From: [e-mail]
Subject:  Pointer arithmatic in P (Thanks)
Date: 4 Feb 92 04:40:21 GMT
Organization: National Research Council

In article <[e-mail]>, [e-mail] writes:
> In article <[e-mail]>, [e-mail] writes:
>> Hi, I usually program in C where pointer arithmatic is widely used. Now, I
>> need a variable 2D array of integers. In C, I would allocate a 1D array and
>> use pointer arithmatic to acces the array as a 2D array. Can you do a similar
>> thing in Pascal?
>
> Depending on the nature of your data, Pascal may provide more elegant
> solutions, but pointer arithmetic works fine in Pascal. To avaiod heap
> fragmentation, allocate space with Newhandle, call MoveHHi and HLock it.
> Call StripAddress on the handle's master pointer and use that as the base of
> the array. Calling ord() on a pointer renders a LongInt, and calling pointer()
> on a LongInt is assignment compatible with any pointer type.
>
> type IntPtr = ^Integer;
> const xDim = columns-1; yDim = rows-1;
> var h: Handle; p: IntPtr;
> ...
> h:= NewHandle(xDim*yDim*2);
> if h <> nil then
>   begin
>     MoveHHi(h);
>     HLock(h);
>     p:= IntPtr(StripAddress(h^))
>   end
> else p:= nil;
> ...
> procedure SetArray(p:IntPtr; x,y,i:Integer; {p^[x,y]:=i}
> begin
>   p:= IntPtr(ord(p) + y*xDim*2 + x*2); {or however you want to base the array}
>   p^:= i
> end;
> ...
> function GetArray(p:IntPtr; x,y:Integer):Integer;
> begin
>   p:= IntPtr(ord(p) + y*xDim*2 + x*2); {or however you want to base the array}
>   GetArray:= p^
> end;
>
> Range checking is left as an exercise. Hope this helps.
>
> o----------------------------------------------------------------------------o
> | John B. Matthews, [e-mail], disclaimer:= myViews <> WSU |
> | "I'm a commensal .sig virus, indistinguishable from an ordinary organelle."|
> o----------------------------------------------------------------------------o

Thanks, that's the way I did it. Except I typed cast the pointer into a Longint
and then back. The reason I asked was that in C you can declare a pointer and
use it like an array, syntax wise. The compiler takes care of addressing
depending on the size of an element. Thanks toIngemar Ragnemalm for a similar
suggestion.

Rodrigo.



- -------------------------

From: [e-mail] (Andrew Dent)
Subject:  Pointer arithmatic in P (Thanks)
Date: 7 Feb 92 13:50:06 GMT
Organization: DIALix Services, Perth, Western Australia

To save type-casting for pointer increments, I wrote the following
library. Note that it costs a LITTLE in performance, pushing the arguments
on the stack, compared to straight addition code, but may be worth it for
readability:

Andy - share and enjoy!

unit ptrTools;
{ functions for incrementing and decrementing various 2 and 4 byte values }
{  EG:  incP(aPtr)      nextPtr:=plus1P(aPtr)        less4I(integerToDecrease) }

{ copyright 1990 A.D. Software, free for all use provided this }
{ copyright notice retained }

{ "Ad ware" - other products that may interest you:  }
{ Shareware: Fast File Compare }
{ Freeware: various Hypercard & FoxBASE+/Mac XCMDS, including }
{setting SF open/save path, get monitor bit depth etc. }
{ and Think Pascal Code & Resource for an Open dialog with prompt string }

{ Retail: Fortran->Pascal translator and Fortran formatted}
 {I/O runtime libraries.  }
{ COMING SOON - classified magazine entry/management/printing system }

{Andy Dent                          A.D. Software phone/fax [phone] }
{    Mac & VAX programmer           94 Bermuda Dve , Ballajura}
{    Internet: [e-mail]    Western Australia 6066}
{    Compuserve: 100033,3241 }

{ NOTE:  if you want to increase the constants (up to 8) then change }
{  the second digit of the SUBQ or ADDQ line }
{  ADD is even, 0=8  2=1  4=2  6=3  8=4  A=5  C=6  E=7 }
{  SUB is odd,   1=8  3=1  5=2  7=3  9=4  B=5  D=6  F=7 }


interface


{************************************************************}
{                   L O N G I N T                            }
{************************************************************}

{             F U N C T I O N S                         }

 function Plus1L (l: longint): longint;
 inline
  $5297, {ADDQ.L #$1, (A7) }
  $2E9F;  {MOVE.L (A7)+, (A7) }

 function Plus2L (l: longint): longint;
 inline
  $5497, {ADDQ.L #$2, (A7) }
  $2E9F;  {MOVE.L (A7)+, (A7) }

 function Plus3L (l: longint): longint;
 inline
  $5697, {ADDQ.L #$3, (A7) }
  $2E9F;  {MOVE.L (A7)+, (A7) }

 function Plus4L (l: longint): longint;
 inline
  $5897, {ADDQ.L #$4, (A7) }
  $2E9F;  {MOVE.L (A7)+, (A7) }


 function Less1L (l: longint): longint;
 inline
  $5397, {SUBQ.L #$1, (A7) }
  $2E9F;  {MOVE.L (A7)+, (A7) }

 function Less2L (l: longint): longint;
 inline
  $5597, {SUBQ.L #$2, (A7) }
  $2E9F;  {MOVE.L (A7)+, (A7) }

 function Less3L (l: longint): longint;
 inline
  $5797, {SUBQ.L #$3, (A7) }
  $2E9F;  {MOVE.L (A7)+, (A7) }

 function Less4L (l: longint): longint;
 inline
  $5997, {SUBQ.L #$4, (A7) }
  $2E9F;  {MOVE.L (A7)+, (A7) }




{                   P R O C E D U R E S                      }
 procedure incL (var l: longint);
 inline
  $205f, {MOVEA.L (A7)+, A0 }
  $5290; {ADDQ.L #$1, (A0) }

 procedure inc2L (var l: longint);
 inline
  $205f, {MOVEA.L (A7)+, A0 }
  $5490; {ADDQ.L #$2, (A0) }

 procedure inc3L (var l: longint);
 inline
  $205f, {MOVEA.L (A7)+, A0 }
  $5690; {ADDQ.L #$3, (A0) }

 procedure inc4L (var l: longint);
 inline
  $205f, {MOVEA.L (A7)+, A0 }
  $5890; {ADDQ.L #$4, (A0) }


 procedure decL (var l: longint);
 inline
  $205f, {MOVEA.L (A7)+, A0 }
  $5390; {SUBQ.L #$1, (A0) }

 procedure dec2L (var l: longint);
 inline
  $205f, {MOVEA.L (A7)+, A0 }
  $5590; {SUBQ.L #$2, (A0) }

 procedure dec3L (var l: longint);
 inline
  $205f, {MOVEA.L (A7)+, A0 }
  $5790; {SUBQ.L #$3, (A0) }

 procedure dec4L (var l: longint);
 inline
  $205f, {MOVEA.L (A7)+, A0 }
  $5990; {SUBQ.L #$4, (A0) }



{***********************************************}
{                    P T R                      }
{***********************************************}

{                    F U N C T I O N S           }
 function Plus1P (p: univ ptr): ptr;
 inline
  $5297, {ADDQ.L #$1, (A7) }
  $2E9F;  {MOVE.P (A7)+, (A7) }

 function Plus2P (p: univ ptr): ptr;
 inline
  $5497, {ADDQ.L #$2, (A7) }
  $2E9F;  {MOVE.P (A7)+, (A7) }

 function Plus3P (p: univ ptr): ptr;
 inline
  $5697, {ADDQ.L #$3, (A7) }
  $2E9F;  {MOVE.P (A7)+, (A7) }

 function Plus4P (p: univ ptr): ptr;
 inline
  $5897, {ADDQ.L #$4, (A7) }
  $2E9F;  {MOVE.P (A7)+, (A7) }


 function Less1P (p: univ ptr): ptr;
 inline
  $5397, {SUBQ.L #$1, (A7) }
  $2E9F;  {MOVE.P (A7)+, (A7) }

 function Less2P (p: univ ptr): ptr;
 inline
  $5597, {SUBQ.L #$2, (A7) }
  $2E9F;  {MOVE.P (A7)+, (A7) }

 function Less3P (p: univ ptr): ptr;
 inline
  $5797, {SUBQ.L #$3, (A7) }
  $2E9F;  {MOVE.P (A7)+, (A7) }

 function Less4P (p: univ ptr): ptr;
 inline
  $5997, {SUBQ.L #$4, (A7) }
  $2E9F;  {MOVE.P (A7)+, (A7) }




{                       P R O C E D U R E S                    }
 procedure incP (var p: ptr);
 inline
  $205f, {MOVEA.P (A7)+, A0 }
  $5290; {ADDQ.L #$1, (A0) }

 procedure inc2P (var p: ptr);
 inline
  $205f, {MOVEA.P (A7)+, A0 }
  $5490; {ADDQ.L #$2, (A0) }

 procedure inc3P (var p: ptr);
 inline
  $205f, {MOVEA.P (A7)+, A0 }
  $5690; {ADDQ.L #$3, (A0) }

 procedure inc4P (var p: ptr);
 inline
  $205f, {MOVEA.P (A7)+, A0 }
  $5890; {ADDQ.L #$4, (A0) }


 procedure decP (var p: ptr);
 inline
  $205f, {MOVEA.P (A7)+, A0 }
  $5390; {SUBQ.L #$1, (A0) }

 procedure dec2P (var p: ptr);
 inline
  $205f, {MOVEA.P (A7)+, A0 }
  $5590; {SUBQ.L #$2, (A0) }

 procedure dec3P (var p: ptr);
 inline
  $205f, {MOVEA.P (A7)+, A0 }
  $5790; {SUBQ.L #$3, (A0) }

 procedure dec4P (var p: ptr);
 inline
  $205f, {MOVEA.P (A7)+, A0 }
  $5990; {SUBQ.L #$4, (A0) }




{**************************************************}
{                 I N T E G E R                    }
{**************************************************}

{                     F U N C T I O N S            }
 function Plus1I (i: integer): integer;
 inline
  $5257, {ADDQ.W #$1, (A7) }
  $3E9F;  {MOVE.W (A7)+, (A7) }

 function Plus2I (i: integer): integer;
 inline
  $5457, {ADDQ.W #$2, (A7) }
  $3E9F;  {MOVE.W (A7)+, (A7) }

 function Plus3I (i: integer): integer;
 inline
  $5657, {ADDQ.W #$3, (A7) }
  $3E9F;  {MOVE.W (A7)+, (A7) }

 function Plus4I (i: integer): integer;
 inline
  $5857, {ADDQ.W #$4, (A7) }
  $3E9F;  {MOVE.W (A7)+, (A7) }


 function Less1I (i: integer): integer;
 inline
  $5357, {SUBQ.W #$1, (A7) }
  $3E9F;  {MOVE.W (A7)+, (A7) }

 function Less2I (i: integer): integer;
 inline
  $5557, {SUBQ.W #$2, (A7) }
  $3E9F;  {MOVE.W (A7)+, (A7) }

 function Less3I (i: integer): integer;
 inline
  $5757, {SUBQ.W #$3, (A7) }
  $3E9F;  {MOVE.W (A7)+, (A7) }

 function Less4I (i: integer): integer;
 inline
  $5957, {SUBQ.W #$4, (A7) }
  $3E9F;  {MOVE.W (A7)+, (A7) }




{                   P R O C E D U R E S                          }
 procedure incI (var i: integer);
 inline
  $205f, {MOVEA.W (A7)+, A0 }
  $5250; {ADDQ.W #$1, (A0) }

 procedure inc2I (var i: integer);
 inline
  $205f, {MOVEA.W (A7)+, A0 }
  $5450; {ADDQ.W #$2, (A0) }

 procedure inc3I (var i: integer);
 inline
  $205f, {MOVEA.W (A7)+, A0 }
  $5650; {ADDQ.W #$3, (A0) }

 procedure inc4I (var i: integer);
 inline
  $205f, {MOVEA.W (A7)+, A0 }
  $5850; {ADDQ.W #$4, (A0) }


 procedure decI (var i: integer);
 inline
  $205f, {MOVEA.W (A7)+, A0 }
  $5350; {SUBQ.W #$1, (A0) }

 procedure dec2I (var i: integer);
 inline
  $205f, {MOVEA.W (A7)+, A0 }
  $5550; {SUBQ.W #$2, (A0) }

 procedure dec3I (var i: integer);
 inline
  $205f, {MOVEA.W (A7)+, A0 }
  $5750; {SUBQ.W #$3, (A0) }

 procedure dec4I (var i: integer);
 inline
  $205f, {MOVEA.W (A7)+, A0 }
  $5950; {SUBQ.W #$4, (A0) }

implementation
end.



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Pointer arithmatic in Pascal question
Date: 30 Jan 92 22:52:28 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] writes:
>> Hi, I usually program in C where pointer arithmatic is widely used. Now, I
>> need a variable 2D array of integers. In C, I would allocate a 1D array and
>> use pointer arithmatic to acces the array as a 2D array. Can you do a similar
>> thing in Pascal?
>
>Depending on the nature of your data, Pascal may provide more elegant
>solutions, but pointer arithmetic works fine in Pascal. To avaiod heap
>fragmentation, allocate space with Newhandle, call MoveHHi and HLock it.
>Call StripAddress on the handle's master pointer and use that as the base of
>the array. Calling ord() on a pointer renders a LongInt, and calling pointer()
>on a LongInt is assignment compatible with any pointer type.

I'd suggest taking a little different approach the one described above.
Given the original poster's needs, there should be no need to move the
handle high in the heap, lock it, or call StripAddress on the master
pointer. On the other hand, there are several reason why you shouldn't
call those routines. Instead, assuming an array of integers, use
something like the following:

TYPE
    IntArray = ARRAY [0..0] OF INTEGER;    { actually variable sized }
    IntArrayPtr = ^IntArray;
    IntArrayHdl = ^IntArrayPtr;

VAR
    myArray: IntArrayHdl;

BEGIN
    myArray = IntArrayHdl(NewHandle(someSize));
    { now initialize all elements to one. }
    for i := 0 to width do begin
        for j := 0 to height do begin
        {$PUSH} {$R-} {turn off range checking}
        myArray^^[j*width+i] := 1;
        {$POP} {restore previsous settings}
        end;
    end;
END.

This is just off the top of my head, so I hope I'm not too far off.

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



---------------------------

From: [e-mail] (Matthew Hall)
Subject: Code modules in a program - how to implement?
Date: 28 Jan 92 21:05:43 GMT
Organization: Oberlin College Computer Science

Hello -
    My question is this - How can I write a program that will, at
run time, load a code resource, and pass information to it, and then
have the code resource return to the original program, passing more
information.  I am thinking along the lines of Mandelzot, where
the program acts as a shell almost and programmers can create their
own modules to do what they want.
    I assume I will have to use assembly - which is not too good
for me, but if I don't need to do too much I can use Think Pascal's
inline assembler.  Also, it seems, I can not use global variables or
call new() or dispose() frome the code - but I can probably deal with
that. Would it be a question of loading the code resoursce, locking
it, pushing the variables onto the stack, and then jumping to the code
resources handle? (The code resource would be structured like a DA or
CDEV - one procedure at the start of the code that takes messages and
information and passes them on)  Am I being way too naive?  Can you
help me? Please respond.

Matt Hall
[e-mail]
--

<<[e-mail] OR
<<[e-mail]

This is just a beta version signature



- -------------------------

From: [e-mail] (Matthew Hall)
Subject: Code Modules - how to use.
Date: 29 Jan 92 21:43:57 GMT
Organization: Oberlin College Computer Science


    I have had several inquiries for a followup since I asked my
question of how to call, at runtime, other code resources that were
not linked to the main program at compile time.  These can be written
by other programmers to add different functions or effects to a main
program - MandelZot and IFS (I think) use this so that programmers can
add new fractal algorithms.
    The only response that I have had so far is to look in Tech
Note #256.  It's availible in the Tech Note Stack from ftp.apple.com
or individually at archive.umich.edu
(/mac/development/apple/tech.notes/tn.251.300)
I haven't had a chance to download it yet. (I tried downloading the
TNStack a few weeks ago, but it got corrupted in the process, and
destroyed my system 7 folder when I tried to unstuff it.  That's okay,
I was getting sick of Sys 7 anyways.  And the neat thing is, alaises I
made under Sys 7 work under sys 6.0.7.  But I digress)
    Anyway, if anyone else has more information, please reply and
I will summarize.

Thank you-
Matt Hall

--

<<[e-mail] OR
<<[e-mail]

This is just a beta version signature



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Code modules in a program - how to implement?
Date: 30 Jan 92 22:21:01 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] (Matthew Hall) writes:
>Hello -
>    My question is this - How can I write a program that will, at
>run time, load a code resource, and pass information to it, and then
>have the code resource return to the original program, passing more
>information.  I am thinking along the lines of Mandelzot, where
>the program acts as a shell almost and programmers can create their
>own modules to do what they want.
>    I assume I will have to use assembly - which is not too good
>for me, but if I don't need to do too much I can use Think Pascal's
>inline assembler.  Also, it seems, I can not use global variables or
>call new() or dispose() frome the code - but I can probably deal with
>that. Would it be a question of loading the code resoursce, locking
>it, pushing the variables onto the stack, and then jumping to the code
>resources handle? (The code resource would be structured like a DA or
>CDEV - one procedure at the start of the code that takes messages and
>information and passes them on)  Am I being way too naive?  Can you
>help me? Please respond.

I guess you're using Pascal, but this is easier in C, so I'll show
it first.

Assume you want to call a function with the following declaration:

long myFunc(short, long);

Further assume that this function is in the external resource PROC(1),
with the entry point at the first byte of the resource. You would then
use the following code to call it:

typedef long (*MyFuncPtr)(short, long);

Handle    myCode;

myCode = GetResource('PROC', 1);
myLongResult = ((MyFuncPtr) *myCode)(myShort, myLong);

In Pascal, it is more difficult to deal with function pointers.  I
believe that you would have to use something like the following:

FUNCTION CallExternal(someInteger: INTEGER; someLong: LONGINT;
            someProc: Ptr): LONGINT;
    INLINE $205F,        { MOVE.L (A7)+,A0 }
           $4E90;        { JSR    (A0)     }

myCode:    Handle;

myCode := GetResource('PROC', 1);
myLongResult := CallExternal(myInteger, myLong, myCode^);

My Pascal is a little rusty, so I hope I'm not too far off.

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



- -------------------------

From: [e-mail] (Christopher Tate)
Subject:  Code modules in a program - how to implement?
Date: 31 Jan 92 02:46:26 GMT
Organization: Penn State University

In article <[e-mail]>, [e-mail] (Keith Rollin) says:
>
>Assume you want to call a function with the following declaration:
>
>long myFunc(short, long);
>
>Further assume that this function is in the external resource PROC(1),
>with the entry point at the first byte of the resource. You would then
>use the following code to call it:
>
>typedef long (*MyFuncPtr)(short, long);
>
>Handle  myCode;
>
>myCode = GetResource('PROC', 1);
>myLongResult = ((MyFuncPtr) *myCode)(myShort, myLong);

Shouldn't you flush the caches between the GetResource() and the function
call so as not to terminally confuse a Quadra?

Or am I completely off base on just when you should and shouldn't flush
the caches?  The subject has come up recently, but I haven't seen any
explanation of *when* this sort of thing is necessary.  Maybe it's time
for something like the "When to call StripAddress()" tech note....

- -----
Christopher Tate     | Cryptogram #16:
[e-mail] |
[e-mail]  |   JUI EKO AJ BKSI OJPF JZM NKF FPU YIAAIF
- -------------------|   XV AJ ZJJS PQ ALI QFXNI JC K UIE JUI.
Send me the answer!  |



- -------------------------

From: [e-mail] (Thom Phillabaum)
Subject:  Code modules in a program - how to implement?
Date: 31 Jan 92 21:08:15 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

One small, somewhat subtle detail is that you should also lock the handle to
the CODE resource.  Otherwise, if the CODE resource makes any toolbox call
the Memory Manager is likely to scoot things around (including the code it's
executing) when compacting the heap.  Needless to say, this would be a
sub-optimal situation.  Anyway, that's my two bits...

[e-mail]



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Code modules in a program - how to implement?
Date: 3 Feb 92 03:09:52 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] (Christopher Tate) writes:
>In article <[e-mail]>, [e-mail] (Keith Rollin) says:
>>
>>Assume you want to call a function with the following declaration:
>>
>>long myFunc(short, long);
>>
>>Further assume that this function is in the external resource PROC(1),
>>with the entry point at the first byte of the resource. You would then
>>use the following code to call it:
>>
>>typedef long (*MyFuncPtr)(short, long);
>>
>>Handle  myCode;
>>
>>myCode = GetResource('PROC', 1);
>>myLongResult = ((MyFuncPtr) *myCode)(myShort, myLong);
>
>Shouldn't you flush the caches between the GetResource() and the function
>call so as not to terminally confuse a Quadra?
>
>Or am I completely off base on just when you should and shouldn't flush
>the caches?  The subject has come up recently, but I haven't seen any
>explanation of *when* this sort of thing is necessary.  Maybe it's time
>for something like the "When to call StripAddress()" tech note....

You're completely correct in that the instruction cache should be
cleared when loading in a resource with executable code in it.
Fortunately, GetResource and LoadResource do this for you.

Flushing the instruction cache is necessary if you whip up instructions
on the fly. For instance, a common method for implementing things like
custom control and menus includes utilizing a 6 byte resource. The
first word of the resource contains a JMP instruction, and the
following long word gets filled in by the application with the address
of the application function that implements the 'real' defProc code.
After this address is written, the instruction cache should be
flushed. On the other hand, if the JMP $xxxxxxxx instruction in the
resource were replaced with something like the following, you wouldn't
need to worry about flushing the cache:

MyMDEF    PROC

    LEA    Address,A0
    MOVE.L    (A0),A0
    JMP    (A0)
Address    DC.L    0        ; Get's filled in by application
                ; after resource is loaded.
    ENDP

(I can't remember if the first two instructions can be shortened to
a mere MOVE.L Address,A0 so please excuse any verbosity.)

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Code modules in a program - how to implement?
Date: 30 Jan 92 22:21:01 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] (Matthew Hall) writes:
>Hello -
>    My question is this - How can I write a program that will, at
>run time, load a code resource, and pass information to it, and then
>have the code resource return to the original program, passing more
>information.  I am thinking along the lines of Mandelzot, where
>the program acts as a shell almost and programmers can create their
>own modules to do what they want.
>    I assume I will have to use assembly - which is not too good
>for me, but if I don't need to do too much I can use Think Pascal's
>inline assembler.  Also, it seems, I can not use global variables or
>call new() or dispose() frome the code - but I can probably deal with
>that. Would it be a question of loading the code resoursce, locking
>it, pushing the variables onto the stack, and then jumping to the code
>resources handle? (The code resource would be structured like a DA or
>CDEV - one procedure at the start of the code that takes messages and
>information and passes them on)  Am I being way too naive?  Can you
>help me? Please respond.

I guess you're using Pascal, but this is easier in C, so I'll show
it first.

Assume you want to call a function with the following declaration:

long myFunc(short, long);

Further assume that this function is in the external resource PROC(1),
with the entry point at the first byte of the resource. You would then
use the following code to call it:

typedef long (*MyFuncPtr)(short, long);

Handle    myCode;

myCode = GetResource('PROC', 1);
myLongResult = ((MyFuncPtr) *myCode)(myShort, myLong);

In Pascal, it is more difficult to deal with function pointers.  I
believe that you would have to use something like the following:

FUNCTION CallExternal(someInteger: INTEGER; someLong: LONGINT;
            someProc: Ptr): LONGINT;
    INLINE $205F,        { MOVE.L (A7)+,A0 }
           $4E90;        { JSR    (A0)     }

myCode:    Handle;

myCode := GetResource('PROC', 1);
myLongResult := CallExternal(myInteger, myLong, myCode^);

My Pascal is a little rusty, so I hope I'm not too far off.

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



---------------------------

From: [e-mail] (Jim Walker)
Subject: How do you write an MDEF that handles scrolling?
Organization: Univ. of S. Carolina, Department of Mathematics
Date: Wed, 29 Jan 1992 13:31:53 GMT


Does anyone know where I can get sample code for an MDEF that handles
pop-ups and scrolling?  Inside Mac is pretty sketchy on scrolling.
Specifically, what are the low-memory globals AtMenuBottom and MBSaveLoc
used for?  (I think I understand about TopMenuItem.)

The Pascal MDEF in the May '91 Snippets does not handle scrolling.  The
skeleton MDEF in THINK Reference does not handle scrolling.  The UMPG does
not discuss the subject.
--
  -- Jim Walker [e-mail]  [e-mail]



- -------------------------

From: [e-mail] (Carl W. Haynes III)
Subject:  How do you write an MDEF that handles scrolling?
Date: 29 Jan 92 21:20:12 GMT
Organization: Purdue University Computing Center

In article <[e-mail]> [e-mail] writes:
>
>Does anyone know where I can get sample code for an MDEF that handles
>pop-ups and scrolling?  Inside Mac is pretty sketchy on scrolling.
>Specifically, what are the low-memory globals AtMenuBottom and MBSaveLoc
>used for?  (I think I understand about TopMenuItem.)

The example MDEF in Dave Mark's "Macintosh C programming Promer Vol II"
handles both scrolling and pop-ups. The example
in the text of the book doesn't handle these, but if you look at the
code in Appendix B, this code has been added.

carl
[e-mail]



- -------------------------

From: [e-mail] (Phil Shapiro)
Subject:  How do you write an MDEF that handles scrolling?
Date: 29 Jan 92 22:53:56 GMT
Organization: Symantec Corp.

>>>>> On Wed, 29 Jan 1992 13:31:53 GMT, [e-mail] (Jim Walker) said:

 > Does anyone know where I can get sample code for an MDEF that
 > handles pop-ups and scrolling?  Inside Mac is pretty sketchy on
 > scrolling.  Specifically, what are the low-memory globals
 > AtMenuBottom and MBSaveLoc used for?  (I think I understand about
 > TopMenuItem.)

 > The Pascal MDEF in the May '91 Snippets does not handle scrolling.
 > The skeleton MDEF in THINK Reference does not handle scrolling.
 > The UMPG does not discuss the subject.

Hi Jim,

How about the MDEF that Apple has released? It doesn't do pop-ups (I
think), but it does hierarchical menus and scrolling. It's on the
developer CDs, and you can ftp it from ftp.apple.com (in
dts/mac/defprocs.6.0.x). The readme there claims that it's from System
6.0.4.

    -phil
- --
   Phil Shapiro                           Technical Support Analyst
   Language Products Group                     Symantec Corporation
        Internet: [e-mail]
--
   Phil Shapiro                           Technical Support Analyst
   Language Products Group                     Symantec Corporation
        Internet: [e-mail]



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  How do you write an MDEF that handles scrolling?
Date: 30 Jan 92 23:29:08 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] (Phil Shapiro) writes:
>>>>>> On Wed, 29 Jan 1992 13:31:53 GMT, [e-mail] (Jim Walker) said:
>
> > Does anyone know where I can get sample code for an MDEF that
> > handles pop-ups and scrolling?  Inside Mac is pretty sketchy on
> > scrolling.  Specifically, what are the low-memory globals
> > AtMenuBottom and MBSaveLoc used for?  (I think I understand about
> > TopMenuItem.)
>
> > The Pascal MDEF in the May '91 Snippets does not handle scrolling.
> > The skeleton MDEF in THINK Reference does not handle scrolling.
> > The UMPG does not discuss the subject.
>
>How about the MDEF that Apple has released? It doesn't do pop-ups (I
>think), but it does hierarchical menus and scrolling. It's on the
>developer CDs, and you can ftp it from ftp.apple.com (in
>dts/mac/defprocs.6.0.x). The readme there claims that it's from System
>6.0.4.

I'm pretty sure the Apple provided MDEF source handles popups, since
it's straight out of the source code used to build the System. However,
since it's from 6.0.4, it doesn't handle the new 7.0 things, like true
gray for disabled items and help balloons.

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  How do you write an MDEF that handles scrolling?
Date: 30 Jan 92 23:29:08 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] (Phil Shapiro) writes:
>>>>>> On Wed, 29 Jan 1992 13:31:53 GMT, [e-mail] (Jim Walker) said:
>
> > Does anyone know where I can get sample code for an MDEF that
> > handles pop-ups and scrolling?  Inside Mac is pretty sketchy on
> > scrolling.  Specifically, what are the low-memory globals
> > AtMenuBottom and MBSaveLoc used for?  (I think I understand about
> > TopMenuItem.)
>
> > The Pascal MDEF in the May '91 Snippets does not handle scrolling.
> > The skeleton MDEF in THINK Reference does not handle scrolling.
> > The UMPG does not discuss the subject.
>
>How about the MDEF that Apple has released? It doesn't do pop-ups (I
>think), but it does hierarchical menus and scrolling. It's on the
>developer CDs, and you can ftp it from ftp.apple.com (in
>dts/mac/defprocs.6.0.x). The readme there claims that it's from System
>6.0.4.

I'm pretty sure the Apple provided MDEF source handles popups, since
it's straight out of the source code used to build the System. However,
since it's from 6.0.4, it doesn't handle the new 7.0 things, like true
gray for disabled items and help balloons.

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



---------------------------

From: [e-mail] (|S| Tilman Haerdle)
Subject: Select Directory dialog
Date: 29 Jan 1992 13:13:54 GMT
Organization: University of Karlsruhe, FRG (Informatik Rechnerabteilung)

Hi,

i would like to implement a dialog box to allow the user choosing a directory
similar to the standard "open file"-dialog. mpw poses such a dialog, when i have
installed MacApp (dialog : "Where is your MacApp folder

anyone out there who has customized sfpgetfile or has done it using
MacApp 2.0 ???????

thanks,

tilman




- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Select Directory dialog
Date: 30 Jan 92 22:40:06 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] (|S| Tilman Haerdle) writes:
>Hi,
>
>i would like to implement a dialog box to allow the user choosing a directory
>similar to the standard "open file"-dialog. mpw poses such a dialog, when i have
>installed MacApp (dialog : "Where is your MacApp folder
>
>anyone out there who has customized sfpgetfile or has done it using
>MacApp 2.0 ???????

Mac DTS Sample Code #18: Stdfile addresses this issue. You can get this
sample code from Apple's ftp site (ftp.apple.com), from APDA, or from
many other ftp sites and BBS's.

The sample code sited customizes SFPGetFile. While it was not written
with MacApp in mind, there is no reason why you cannot incorporate into
your MacApp program.

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Select Directory dialog
Date: 30 Jan 92 22:40:06 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] (|S| Tilman Haerdle) writes:
>Hi,
>
>i would like to implement a dialog box to allow the user choosing a directory
>similar to the standard "open file"-dialog. mpw poses such a dialog, when i have
>installed MacApp (dialog : "Where is your MacApp folder
>
>anyone out there who has customized sfpgetfile or has done it using
>MacApp 2.0 ???????

Mac DTS Sample Code #18: Stdfile addresses this issue. You can get this
sample code from Apple's ftp site (ftp.apple.com), from APDA, or from
many other ftp sites and BBS's.

The sample code sited customizes SFPGetFile. While it was not written
with MacApp in mind, there is no reason why you cannot incorporate into
your MacApp program.

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



---------------------------

From: [e-mail] (Eric W. Sink)
Subject: Where's that code frag that finds the app file ?
Date: 29 Jan 92 16:45:16 GMT
Organization: University of Illinois at Urbana-Champaign

People have asked this before, but I need that piece of code which
finds the location of its own application file.  I want to locate
the app and search in that directory for some files.

Wasn't it something like CurResFile() and then some PBstuffCalls ?

Is in the UMPG ?  (I know I've seen it somewhere... :-)

adThanksvance.

--
Eric W. Sink,  Spatial Analysis and Systems Team
USACERL, P.O. Box 9005, Champaign, IL 61826-9005
1-800-USA-CERL x449,   [e-mail]



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Where's that code frag that finds the app file ?
Date: 30 Jan 92 22:55:09 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] writes:
>People have asked this before, but I need that piece of code which
>finds the location of its own application file.  I want to locate
>the app and search in that directory for some files.
>
>Wasn't it something like CurResFile() and then some PBstuffCalls ?
>
>Is in the UMPG ?  (I know I've seen it somewhere... :-)

Probably Inside Mac. The call you want is HGetVol. Call it when
your application starts up, and before you change the default
directory (if you do that at all).

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



- -------------------------

From: [e-mail]
Subject:  Where's that code frag that finds the app file ?
Date: 1 Feb 92 04:09:22 GMT
Organization: Wright State University

In article <[e-mail]>, [e-mail] (Keith Rollin) writes:
> In article <[e-mail]> [e-mail] writes:
>>People have asked this before, but I need that piece of code which
>>finds the location of its own application file.  I want to locate
>>the app and search in that directory for some files.
>>
>>Wasn't it something like CurResFile() and then some PBstuffCalls ?
>>
>>Is in the UMPG ?  (I know I've seen it somewhere... :-)
>
> Probably Inside Mac. The call you want is HGetVol. Call it when
> your application starts up, and before you change the default
> directory (if you do that at all).

Also call the Segment Loader's GetAppParms to find out what the user has
(re)named your application.

o----------------------------------------------------------------------------o
| John B. Matthews, [e-mail], disclaimer:= myViews <> WSU |
| "I'm a commensal .sig virus, indistinguishable from an ordinary organelle."|
o----------------------------------------------------------------------------o



- -------------------------

From: [e-mail] (Keith Rollin)
Subject:  Where's that code frag that finds the app file ?
Date: 30 Jan 92 22:55:09 GMT
Organization: Apple Computer Inc., Cupertino, CA

In article <[e-mail]> [e-mail] writes:
>People have asked this before, but I need that piece of code which
>finds the location of its own application file.  I want to locate
>the app and search in that directory for some files.
>
>Wasn't it something like CurResFile() and then some PBstuffCalls ?
>
>Is in the UMPG ?  (I know I've seen it somewhere... :-)

Probably Inside Mac. The call you want is HGetVol. Call it when
your application starts up, and before you change the default
directory (if you do that at all).

--
- ----------------------------------------------------------------------------
Keith Rollin           ---            <Taligent .signature under construction>
Disclaimer: Pretty soon, I really _won't_ be speaking for Apple...



---------------------------

End of C.S.M.P. Digest
**********************