Celestin Apprentice 2/Apprentice-Release2.iso/Information/Digests/CSMP Digest/volume 1/csmp-v1-127.txt

Text File | 1994-12-08 | 40.3 KB | 1,161 lines | [TEXT/R*ch]

C.S.M.P. Digest             Tue, 30 Jun 92       Volume 1 : Issue 127

Today's Topics:

    PBLockRange
    HELP: How do traps/selectors work?
    Notification Mgr. Question
    Is MacApp 3.0 available???
    Using Menus during Interrupts???
    Color QuickDraw and GWorlds
    Number of strings in a STR#?
    MPW C and > 32K structs
    How to tell if monitor is in color was(Re: Most efficient bla, bla...)
    Need help with INITs (specifically, patching traps)
    MacBinary format and empty forks
    REWARD OFFERED: Think C Multisegment Driver Problem



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

From: [e-mail] (David Castell)
Subject: PBLockRange
Organization: Computer Systems Group
Date: Tue, 26 May 1992 17:04:56 GMT

In IM-IV is says that the PBLockRange call can be used on files that are
open in shared mode.  However, it has been my observation that this call
can't be used on just any volume, but only works on shared volumes.  Is this
call supposed to work on non-shared volumes?

Dave Castell
Computer Systems Group

+++++++++++++++++++++++++++

From: [e-mail] (Pete Gontier)
Date: 29 May 92 16:26:04 GMT

[e-mail] (David Castell) writes:

>In IM-IV is says that the PBLockRange call can be used on files that are
>open in shared mode.  However, it has been my observation that this call
>can't be used on just any volume, but only works on shared volumes.  Is this
>call supposed to work on non-shared volumes?

I was playing around with these calls the other day. I found that I could
not only open a shared file on a local volume, but that I could lock a
range on a file opened read-only on a local volume. I don't know if the
calls had any effect, but they did not generate errors.

I'm running 7.0.1 tuned with 1.1.1 and no file sharing.
- --
 Pete Gontier // EC Technology // [e-mail]

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

From: [e-mail] (Kevin Hill)
Subject: HELP: How do traps/selectors work?
Date: 22 May 92 00:58:25 GMT
Organization: Crash TimeSharing, El Cajon, CA


  I have just purchased books III and IV, and after perusing the globals section
and the system traps sections I have a couple of questions..
  Are these address that contain the address of the Toolbox call in question?
  What is a selector?  Can I put in my own routines at these address locations
and have my program do something before the Toolbox call goes? (I know, I have
to save the A5 environment like i found, is there more I would have to watch
for?)
  Thanks!

  -Kevin Hill

+++++++++++++++++++++++++++

From: [e-mail] (Steve Christensen)
Date: 30 May 92 02:30:20 GMT
Organization: Apple Computer Inc., Cupertino, CA

[e-mail] (Kevin Hill) writes:
>I have just purchased books III and IV, and after perusing the globals section
>and the system traps sections I have a couple of questions..
>  Are these address that contain the address of the Toolbox call in question?
>  What is a selector?  Can I put in my own routines at these address locations
>and have my program do something before the Toolbox call goes? (I know, I have
>to save the A5 environment like i found, is there more I would have to watch
>for?)

Traps are not addresses, they are pseudo-instructions.  Executing a trap
"instruction" causes the CPU to dispatch to the appropriate Toolbox or OS
routine (i.e., putting a size into register D0 and executing the $A022 trap
will call NewHandle).

Selectors are numbers that are passed to some routines that specify which
of the functions that a particular routine performs.  For example, passing
a selector value of 1 to HFSDispatch causes it to perform the OpenWD function.

You can "patch" these trap routines with your own code when you want to do
something in addition to what the routine normally does.  To do this, you
need to call GetTrapAddress to get the address of the original trap routine,
and then call SetTrapAddress to install your routine.  It's your responsibility
to save the original routine's address and call it as part of your patch.
Also, you must observe the register saving convention appropriate for the
trap you are patching, not just saving A5.

steve

- --
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Steve Christensen            Never hit a man with glasses.
  [e-mail]            Hit him with a baseball bat.

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

From: [e-mail] (Steve Herman)
Subject: Notification Mgr. Question
Organization: Boeing Computer Support Services (BCSS)
Date: Fri, 22 May 1992 20:56:32 GMT

Hello all,

    Inside Mac Vol VI states that the nmIcon field of an NMRec can contain "a
handle to a small icon or to an icon family containing a small color icon".
If I get a handle to an 'SICN' resource and plug it into this field
everything works fine.  However, if I try to put a handle to an 'ICN#',
'ics#', 'ics4' or 'ics8' into the field it doesn't work.

    I'm not getting any sort of error on my GetResource call or the NMInstall
call.  And the NMInstall is placing the mark by my application name under the
application menu.

    Just what is meant by a handle to an icon family?  Does anyone know the
trick to get this to work?

Thanks,

Steve


- -------------------------------------
Steve Herman - BCSS
"Happiness is just a 'Flaming Moe' away"
    - Moe the Bartender
- -------------------------------------

+++++++++++++++++++++++++++

From: [e-mail] (Tim Dierks, software saboteur)
Date: 29 May 92 18:10:43 GMT
Organization: MacDTS Misfits

In article <[e-mail]>, [e-mail] (Steve Herman) writes:
>
> Hello all,
>
>     Inside Mac Vol VI states that the nmIcon field of an NMRec can contain "a
> handle to a small icon or to an icon family containing a small color icon".
> If I get a handle to an 'SICN' resource and plug it into this field
> everything works fine.  However, if I try to put a handle to an 'ICN#',
> 'ics#', 'ics4' or 'ics8' into the field it doesn't work.
>
>     I'm not getting any sort of error on my GetResource call or the NMInstall
> call.  And the NMInstall is placing the mark by my application name under the
> application menu.
>
>     Just what is meant by a handle to an icon family?  Does anyone know the
> trick to get this to work?

This line was left in the documentation accidentally; at the time, we did
not document the icon utilities, which is what you need to do this.  However,
now we do, and you should examine Tech Note #306, "Drawing Icons the System
7 Way" for details on creating and using icon families.

Tim Dierks
MacDTS, but I speak for the trees

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

From: quesnel@ems (Rene Quesnel)
Subject: Is MacApp 3.0 available???
Date: 28 May 92 11:38:33 GMT
Organization: Faculty of Music, McGill University

Does anyone has any idea when MacApp 3.0 will be available? Everybody is
talking about it but at APDA, the official word is that it is not
shipping yet (except as part of ETO). We have a project to start with
MacApp. If it is going to be released in a couple weeks, we'll wait for
the new version but if it is going to take another six months, we'll
start with 2.0.1. Does anyone have any info on this?

Thanks,
Rene Quesnel
[e-mail]

+++++++++++++++++++++++++++

From: [e-mail] (Kent Sandvik)
Date: 29 May 92 21:59:10 GMT
Organization: MacDTS Mongols

In article <[e-mail]>, quesnel@ems (Rene
Quesnel) writes:
> Does anyone has any idea when MacApp 3.0 will be available? Everybody is
> talking about it but at APDA, the official word is that it is not
> shipping yet (except as part of ETO). We have a project to start with
> MacApp. If it is going to be released in a couple weeks, we'll wait for
> the new version but if it is going to take another six months, we'll
> start with 2.0.1. Does anyone have any info on this?

   MacApp 3.0 has been available for a long time on ETO (#7), as for a
full APDA product, I think we are talking about weeks or even less,
but someone from the marketing group might know better.
- --
                                              Cheers, Kent


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

From: [e-mail] (Roby Sherman)
Subject: Using Menus during Interrupts???
Date: 27 May 92 13:44:52 GMT
Organization: The Tao of Programming

Hello all...


      I'm trying to write an interrupt based routine that will bring up
a pop-up menu. Once the routine is called, I setup the A5 enviroment,
and I go to call POPUPMENUSELECT. The menu comes up and then the mouse
hangs. Any Idea how I can do this? It must be possible, since OnCueII
and other such programs draw menus at Interrupt time.



         thanks in advance...

                   Roby
- --
[e-mail]                    Roby Sherman

+++++++++++++++++++++++++++

From: [e-mail] (Doug McNaught)
Date: 27 May 92 20:29:03 GMT
Organization: California Institute of Technology

In article <[e-mail]> [e-mail] (Roby Sherman) writes:

   Hello all...


     I'm trying to write an interrupt based routine that will bring up
   a pop-up menu. Once the routine is called, I setup the A5 enviroment,
   and I go to call POPUPMENUSELECT. The menu comes up and then the mouse
   hangs. Any Idea how I can do this? It must be possible, since OnCueII
   and other such programs draw menus at Interrupt time.

No, they don't. They patch traps. Calling the Toolbox at interrupt
time is a good way to crash (can you say "re-entrancy problems? Knew
you could!)
  Try patching FindWindow() or MenuSelect().

regards,
doug
- --
Doug McNaught              |"Sadder still to watch it die/ Then never to have
[e-mail]      | known it/ For you, the blind who once could see/
[e-mail] | The bell tolls for thee..." --Neil Peart
  Nobody approves my opinions! Not even me, sometimes. Read at your own risk.

+++++++++++++++++++++++++++

From: [e-mail] (John Wallace)
Organization: TRW Data Systems Center, Redondo Beach, CA
Date: Thu, 28 May 92 18:34:29 GMT

In article <[e-mail]> [e-mail] (Roby Sherman) writes:
>Hello all...
>
>
>      I'm trying to write an interrupt based routine that will bring up
>a pop-up menu. Once the routine is called, I setup the A5 enviroment,
>and I go to call POPUPMENUSELECT. The menu comes up and then the mouse
>hangs. Any Idea how I can do this? It must be possible, since OnCueII
>and other such programs draw menus at Interrupt time.
>
>                   Roby
>--
>[e-mail]                    Roby Sherman

You shouldn't draw menus at interrupt time since they will definitely
move memory.  You could, however, do it at idle time.  The easiest
way to do this is to install a GNEFilter (which gets called when
ever the program calls GetNextEvent or WaitNextEvent).  Since these
calls are allowed to move memory, then you should be ok.

I have written code that does this, and it does a good job of
letting me to do actions when someone else's program is running.
The only problem is that it won't work unless the active program
calls GetNextEvent.

Cheers!
John

- ----
John Wallace    [e-mail]


+++++++++++++++++++++++++++

From: [e-mail] (Steve Christensen)
Date: 30 May 92 02:37:31 GMT
Organization: Apple Computer Inc., Cupertino, CA

[e-mail] (Roby Sherman) writes:
>      I'm trying to write an interrupt based routine that will bring up
>a pop-up menu. Once the routine is called, I setup the A5 enviroment,
>and I go to call POPUPMENUSELECT. The menu comes up and then the mouse
>hangs. Any Idea how I can do this? It must be possible, since OnCueII
>and other such programs draw menus at Interrupt time.

Are you sure OnCueII, etc., are drawing menus at interrupt time?  Generally,
any kind of drawing that involves QuickDraw can't be done at interrupt time
because heap blocks can move, and the heap could have been in an inconsistent
state.  More than likely they're hooked into GetNextEvent and do the popup
menus at that time...

steve

- --
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Steve Christensen            Never hit a man with glasses.
  [e-mail]            Hit him with a baseball bat.

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

From: [e-mail] (S4161006)
Subject: Color QuickDraw and GWorlds
Organization: University of Massachusetts at Amherst
Date: Wed, 27 May 1992 16:58:03 GMT

I'm about to take the big plunge into graphics with a tetris-like game.
When a piece move I want it to smoothly redraw what was underneath it.  From
reading Inside Mac VI it seem like the Graphics Device Manager off-screen
gWorlds are the way to do this well.  What I had a hard time figuring out is
whether this option is available on a Mac not running System 7.  If not is
there another accepted way of smothly redrawing the window.  Thanks in advance.

Mike Houser
UMass

- -mh

+++++++++++++++++++++++++++

From: [e-mail]
Date: 28 May 92 23:31:38 EST
Organization: Wright State University

In article <[e-mail]>, [e-mail] (S4161006) writes:
> I'm about to take the big plunge into graphics with a tetris-like game.
> When a piece move I want it to smoothly redraw what was underneath it.  From
> reading Inside Mac VI it seem like the Graphics Device Manager off-screen
> gWorlds are the way to do this well.  What I had a hard time figuring out is
> whether this option is available on a Mac not running System 7.  If not is
> there another accepted way of smothly redrawing the window.  Thanks in adv-
> ance.

GWorlds are supposed to be available on all machines running System 7. They are
also available with System 6.0.5 and later if Color QuickDraw is present.
Inside Mac VI suggests that GWorlds should work on non-Color QuickDraw Macs
under System 7.0 given a few precautions. I've had (sorry to whine) no luck
making this happen. Anybody?

A good alternative for non-CQD machines and earlier Systems is Apple's DTS
sample code SC015.OffScreen and SC016.OffSample available from ftp.apple.com
(130.43.2.3) or the d e v e l o p CD.

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] (Eric Brunson)
Subject: Number of strings in a STR#?
Date: 29 May 92 17:51:20 GMT
Organization: Vista-Chrome Incorporated

The first byte of the STR# resource type tells the number
of strings in the string list, but I haven't seen a call
that will return that to my program.  Has anyone ever
come up against this problem?

Please email, I'll summarize if it's non-trivial.

Thanks,
Eric


- --
Eric Brunson               These opinions are mine alone,
[e-mail]         but they could be yours for a low monthly fee!
"He's a genius, eh, he hooked up our stereo."

+++++++++++++++++++++++++++

From: gshields@starfish (Gerald Shields)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Date: Fri, 29 May 1992 22:18:46 GMT

In article <[e-mail]>,
[e-mail] (Eric Brunson) writes:
> Path:
dirtydog.ima.isc.com!newsserver.pixel.kodak.com!rpi!uwm.edu!spool.mu.edu!uunet!r
de!eric
> From: [e-mail] (Eric Brunson)
> Newsgroups: comp.sys.mac.programmer
> Subject: Number of strings in a STR#?
> Message-ID: <[e-mail]>
> Date: 29 May 92 17:51:20 GMT
> Article-I.D.: homebase.1992May29.175120.18368
> Distribution: comp.sys.mac.programmer
> Organization: Vista-Chrome Incorporated
> Lines: 15
>
> The first byte of the STR# resource type tells the number
> of strings in the string list, but I haven't seen a call
> that will return that to my program.  Has anyone ever
> come up against this problem?
>
> Please email, I'll summarize if it's non-trivial.
>
> Thanks,
> Eric
>
>
> --
> Eric Brunson               These opinions are mine alone,
> [e-mail]         but they could be yours for a low monthly fee!
> "He's a genius, eh, he hooked up our stereo."


Eric,

the following code snippet shold do the job

    short num_strings;
    Handle str_h;

    str_h = GetResource( 'STR#', your string ID here );
    if ( str_h == (Handle)0 )
    {
        handle errors here;
    }
    num_strings = (*(short *)(*str_h));
    ReleaseResource( str_h );


Jerry Shields



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

From: Bernhard Damberger <[e-mail]>
Subject: MPW C and > 32K structs
Organization: NCSA - University of Illinois
Date: Thu, 28 May 1992 06:05:44 GMT



+++++++++++++++++++++++++++

From: Bernhard Damberger <[e-mail]>
Organization: NCSA - University of Illinois
Date: Thu, 28 May 1992 06:10:09 GMT

I am getting this annoying message from the MPW C compiler:
    ### Error 427 Can't use structures > 32k

Basically I am trying to port some Unix app to MPW (as a tool) and it has
a huge
pulsating data struct that is (you guessed it) > 32K.  Obviously MPW C
does not
like this.
    I have tried the following compiler options to no avail:

    -bigseg (generate single large (>32K) code segment, 68020 only)
    -m (generate 32-bit references for data (less efficient code))
    -model far (generate load-time relocatable 32-bit references
    for data and code).

Any ideas out there?  Any possible C options that I missed?  Is MPW C
really
this crippled?

Thanks for your help...

+++++++++++++++++++++++++++

From: [e-mail] (Kent Sandvik)
Date: 29 May 92 21:58:11 GMT
Organization: MacDTS Mongols

In article <[e-mail]>, [e-mail] (Bernhard
Damberger) writes:
> I am getting this annoying message from the MPW C compiler:
>     ### Error 427 Can't use structures > 32k
>
> Basically I am trying to port some Unix app to MPW (as a tool) and it has
> a huge
> pulsating data struct that is (you guessed it) > 32K.  Obviously MPW C
> does not
> like this.
>     I have tried the following compiler options to no avail:

>     -bigseg (generate single large (>32K) code segment, 68020 only)
>     -m (generate 32-bit references for data (less efficient code))
>     -model far (generate load-time relocatable 32-bit references
>     for data and code).

> Any ideas out there?  Any possible C options that I missed?  Is MPW C
> really
> this crippled?

"Oh the pain, suffering, and grief, when UNIX programmers try to misuse
the MacOS memory system using malloc and stack based structures."

Yes, the MPW C compiler has a limitation of array/struct sizes, no bigger
than 32k, it's a compiler, not runtime, limitation.

What to do, what to do, check out handles and pointers in the Memory Manager.
And make them as big as you want, as long as end users have memory in their
machines.
- --
                                              Cheers, Kent


+++++++++++++++++++++++++++

From: [e-mail] (Charlie Reiman)
Date: 30 May 92 05:04:17 GMT
Organization: University of Illinois at Urbana

[e-mail] (Kent Sandvik) writes:

>In article <[e-mail]>, [e-mail] (Bernhard
>Damberger) writes:
>> I am getting this annoying message from the MPW C compiler:
>>     ### Error 427 Can't use structures > 32k
>>
>> Basically I am trying to port some Unix app to MPW (as a tool) and it has
>> a huge
>> pulsating data struct that is (you guessed it) > 32K.  Obviously MPW C
>> does not
>> like this.
>>     I have tried the following compiler options to no avail:

>>     -bigseg (generate single large (>32K) code segment, 68020 only)
>>     -m (generate 32-bit references for data (less efficient code))
>>     -model far (generate load-time relocatable 32-bit references
>>     for data and code).

>> Any ideas out there?  Any possible C options that I missed?  Is MPW C
>> really
>> this crippled?

>"Oh the pain, suffering, and grief, when UNIX programmers try to misuse
>the MacOS memory system using malloc and stack based structures."

>Yes, the MPW C compiler has a limitation of array/struct sizes, no bigger
>than 32k, it's a compiler, not runtime, limitation.

>What to do, what to do, check out handles and pointers in the Memory Manager.
>And make them as big as you want, as long as end users have memory in their
>machines.

Bernie had a 2-d array nestled within the data strucure, which isn't
the easiest thing to fake with Handles... Anyway, we managed to figure
out a solution. I don't know if he's tried it yet, but I think it'll
work.

new_thread(): Why is there a 32k limit? We can have over 32k of
globals, segments larger than 32k, code resources of enormous
magnitude-- but C structures are special? I smell something fishy
here.  I don't want to put Apple folks on the spot, but I am curious as
to what gives. I know I'm not the only person to smack his nose against
that particular limit.

Although, I must admit: UNIX programmers do tend to get carried away
with memory allocation. Man, I could tell some stories of attrocious
abuse. I do envy that reckless abandon, though...

- --
Charlie Reiman - [e-mail]
Have a bajillion brilliant Jobsian lithium licks.

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

From: [e-mail] (Matt Mora)
Subject: How to tell if monitor is in color was(Re: Most efficient bla, bla...)
Date: 28 May 92 23:12:43 GMT
Organization: SRI International, Menlo Park, California

In article <[e-mail]> [e-mail] (Lawrence D'Oliveiro, Waikato University) writes:

>> I am writing a custom ldef in pascal (I know this seems to be the major
>> source of my problem) and I want to draw a gray line.

>If you persist in slurring Pascal in this way, I shall be forced to ask
>you to step outside. :-)

I personaly like Pascal and program in it when ever I get a chance. I was
just trying to beat the Pascal bashers to the punch. :-)


>For the particular case of the standard 50% grey pattern, here's a routine
>which will return a PatPtr that you can dereference and pass to the
>appropriate QuickDraw calls:

>    Function grayPtr : PatPtr;
>        Inline
>        $2055,        { move.l (a5), a0 }
>        $41E8, $FFE8,    { lea -24(a0), a0 }
>        $2E88;        { move.l a0, (sp) }

Thanks for the code. I used the one that was posted earlier but I think
yours is the same. Thanks again for such a quick response.

Now for another question. I'm putting a final touch on a program and would
like the button outline to be gray when the button is inactive and on a color
screen. Not just a gray pattern the gray color.

I got the gray part working but how do I know if the button outline
will be drawn in color or b/w? I need to know if the monitor the button
outline is on, is in the 1 bit mode show I can draw the outline in the gray
pattern instead of the gray color. Anyone know how to tell?


Thanks

Matt

- --
___________________________________________________________
Matthew Mora                |   my Mac  [e-mail]
SRI International           |  my unix  [e-mail]
___________________________________________________________

+++++++++++++++++++++++++++

From: [e-mail] (Keith Rollin)
Date: 29 May 92 02:40:50 GMT
Organization: Taligent

In article <[e-mail]>, [e-mail] (Matt Mora) writes:
>
> Now for another question. I'm putting a final touch on a program and would
> like the button outline to be gray when the button is inactive and on a color
> screen. Not just a gray pattern the gray color.
>
> I got the gray part working but how do I know if the button outline
> will be drawn in color or b/w? I need to know if the monitor the button
> outline is on, is in the 1 bit mode show I can draw the outline in the gray
> pattern instead of the gray color. Anyone know how to tell?
>

Well, I'm a System 7 weenie, so I'd use DeviceLoop. It tells you the depth of
the GDevice you are being asked to write to, so you can make your determination
based on that. However, I think that you have to make sure you're drawing into a
CGrafPort (as opposed to a GrafPort) before diving into DeviceLoop.

I did some stuff like this for Mac Programming Secrets. I used DeviceLoop to
draw list items in dithered grey or real grey depending on the what was
available, even if the list crossed monitors of different depths. If you want,
send me mail and I'll send you the code.

If you want to be compatible with 6.0.x, then the coolest thing would be to
write your own version of DeviceLoop (I have a vague feeling that there might be
something on this in DTS's Snippets folder on ftp.apple.com).

- --
Keith Rollin
Phantom Programmer
Taligent, Inc.

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

From: [e-mail] (Mr. Erik Hanson; ARTS-SCI (UGRAD))
Subject: Need help with INITs (specifically, patching traps)
Organization: University of Maryland Baltimore County, Mathematics Department
Date: Fri, 29 May 1992 02:38:56 GMT

Howdy.

I'm writing my first System Extension, and I need a bit o' help.
If anybody can show me some code (or point me towards some code)
that would help me learn how to patch traps (specifically the
StandardGetFile trap, but any trap will do), I'd be grateful.
I've got IM I-VI, but no X-Ref, and I haven't been able to find
any help in there. So, if it is in there, and somebody could tell
me where, I'd be quite happy.

Also, any code for that might help me write an Extension would
also be welcomed.

(And in payment, I'll release my super-cool Extension as
freeware. (And not get-payments-from-both-people-in-the-world-
who-support-sharware-ware. ;-) )


Seeya!
Erk

______________________________________________________________________________
Erik Hanson   University o' Maryland Baltimore County   [e-mail]

+++++++++++++++++++++++++++

From: [e-mail] (Keith Rollin)
Date: 29 May 92 21:23:24 GMT
Organization: Taligent

In article <[e-mail]>,
[e-mail] (Mr. Erik Hanson; ARTS-SCI (UGRAD)) writes:
>
> Howdy.
>
> I'm writing my first System Extension, and I need a bit o' help.
> If anybody can show me some code (or point me towards some code)
> that would help me learn how to patch traps (specifically the
> StandardGetFile trap, but any trap will do), I'd be grateful.
> I've got IM I-VI, but no X-Ref, and I haven't been able to find
> any help in there. So, if it is in there, and somebody could tell
> me where, I'd be quite happy.
>
> Also, any code for that might help me write an Extension would
> also be welcomed.


I patch Standard File in a Boomerang-like INIT that I call Pointed Stick.
Normally, if I were helping someone patch their first trap, I'd start of with
something simple (in Mac Programming Secrets, 2nd Edition, I show how to patch
MenuKey). However, patching Standard File is tricky, because a single trap is
used to dispatch to a number of functions that all take a different set of
parameters.

This is how I patched Standard File in Pointed Stick (using THINK C, which makes
the patching of traps easy by allowing the use of global variables):


void main(void)
{

// Stuff removed for Usenet posting

    Ptr                ourAddress;

// Stuff removed for Usenet posting

    asm {
        move.l    A4,-(sp)            ; save orig A4
        bsr        __GetA4            ; get pointer to saved location
        lea        main,A4            ; get our A4
        move.l    A4,(A1)            ; save it so SetUpA4() will work
        move.l    A4, ourAddress        ; for the RecoverHandle, later

        lea        @continue,A0        ; now, fix up the PC (Technote #245)
        move.l    A0,D0
        StripAddress
        move.l    D0,A0
        jmp        (A0)
    @continue
    }

// Stuff removed for Usenet posting

        gOldStandardFile = GetToolTrapAddress(_Pack3);
        SetToolTrapAddress((long) MyPack3, _Pack3);

// Stuff removed for Usenet posting

    RestoreA4();
}


// Example of struct used in xOffsetToXXX records below:

typedef struct {
    short                selector;
    SFReply*            reply;
    DlgHookProcPtr        dlgHook;
    ConstStr255Param    origName;
    ConstStr255Param    prompt;
    Point                where;
} SFPutFileParameters;


// Example of offset record used below:

short                gOffsetToReply[] = {
                        offsetof(SFPutFileParameters, reply),
                        offsetof(SFGetFileParameters, reply),
                        offsetof(SFPPutFileParameters, reply),
                        offsetof(SFPGetFileParameters, reply),
                        offsetof(StandardPutFileParameters, reply),
                        offsetof(StandardGetFileParameters, reply),
                        offsetof(CustomPutFileParameters, reply),
                        offsetof(CustomGetFileParameters, reply)
                    };



//---------------------------------------------------------------------------
/*
    This is the entry point to most of what Pointed Stick does. ItUs pretty
    gnarly, so IUd better get this down while I can still figure it out.

    The idea behind this patch to Standard File is to do two things:
        % Make sure everything is OK for me to hook in, and
        % Hook me in.

    The first thing we do is set up our A4, strip off the return address
    and save it for later, and take a look at the selector. If the selector
    is not one that we know (from 1 to 8, inclusive), we just call the
    standard Standard File without any funny stuff. ItUs called just as
    if we didnUt exist (except that we are tail-patched, here).

    Next, we try to open our INITUs resource fork. WeUll need a lot of
    things from it, like MENUs, ALRTs, etc. We open the resource fork
    using MyOpenResFile, which opens the resource fork, shuffles the
    resource chain so that my map appears just before the System resource
    map and -- presumably -- after the applicationUs. If we canUt open
    our resource fork, we blow out in the same way as if the selector
    was out of range.

    At this point, we do one of two things. If the user had selected a
    file from the hierarchical menu we attached to the Open menu item,
    we are in the middle of puppet-stringing a response. If this is the
    case, we call FakePack3, which fills in the reply record with something
    appropriate, and then return to the caller just as if Standard File
    had really interacted with the user. This is identical in concept
    with what MultiFinder does with non-Apple Event aware applications.

    If we arenUt puppet-stringing, then itUs time for us to hook ourselves
    in to Standard File. This consists of two phases. First, we can only
    hook ourselves in properly if the caller makes one of those RSFPS or
    RCustomS calls. If they didnUt, the first thing we do is convert
    the parameters on the stack and change the selector so it looks to
    Standard File like the caller _did_ make a custom call. Second, we
    replace the dlgHook, filterProc, and modalFilter parameters with
    pointers to our own procedures, saving the callerUs so that we can
    chain to them when necessary.

    Now weUre almost ready to fall into Standard File. ThereUre only
    a few things we still have to do. First, we put ourself into
    a state that will cause us to munge the next dialog created so that
    it has the menubar across the top. Second, we put ourself into a
    state that will start the sequence of events that will find the
    handle to the ListRecord holding the files and directories appearing
    in the dialog (see the comments in GetItemList.c to see how this
    happens). Third, we clear out the variables holding the previous
    volume and directory we were in. These values are used for rebounding.
    We set them to illegal values to force the rebound routines to
    select the initial file. Finally, we turn off CEToolbox hotkeys so
    that the user canUt bring up MiniFinder while weUre in Standard
    File. If the user did that, Standard File would re-enter itself,
    which is a Bad Thing.

    Finally, we chain to the original Standard File entry point. At
    this point, the dialog appears and the user interacts with it. When
    the user closes the dialog, it goes away, and Standard File returns
    to us. All we have to do now is turn the CEToolbox hotkeys back on
    and close our resource file. Once thatUs done, we return to the
    caller.
*/

pascal void MyPack3()
{
    SetUpA4();
    asm {
        move.l    (sp)+,pSavedA4
        move.l    (sp)+,pSavedReturnAddress
        move.w    (sp),D0
        beq        @NoFunnyStuff                ; skip if selector is zero
        cmp.w    #customGetFile,D0
        bhi        @NoFunnyStuff                ; skip if selector is too large
        bsr        ControlKeyIsDown
        tst.b    D0
        bne        @NoFunnyStuff                ; skip if control key is down

        pea        pCloseIt
        move.w    #fsRdPerm,-(sp)                ; push access priv for our resource file
        lea        gMe,A0                        ; push name for our resource file
        move.l    A0,-(sp)
        jsr        MyOpenResFile                ; try to open it
        add        #4+4+2,A7                    ; remove my parameters
        moveq    #-1,D1                        ; see if we failed (check refNum == -1)
        cmp.w    D1,D0
        beq        @NoFunnyStuff                ; if failed, skip special effects
        move.w    D0,gRefNum                    ; save refnum so we can close it later

        move.w    gStandardFileMode,D0
        beq.s    @HookInMyProcs

        bsr        FakePack3                    ; do special effects

        lea        pParameterSizes,A0            ; pull off StdFile parameters. Get size
        move.w    (sp),D0                        ; ...of parameters from table
        add.w    D0,D0
        move.w    -2(A0,D0.W),D0
        add.w    D0,A7                        ; add size to stack pointer

        bra        @CloseUp

    @HookInMyProcs
        move.w    (sp)+,D0                    ; put selector in D0
        move.w    D0,pOrigSelector            ; save what the user passed in
        sub.w    #1,D0                        ; make it zero based
        btst    #1,D0                        ; is this a Custom or P routine?
        bne.s    @NoConversionNeeded            ; yes, so donUt convert it

        move.w    D0,D1                        ; use D1 for table index
        add.w    D1,D1                        ; double for 2 byte table entries

        lea        pDialogIDs,A0
        move.w    (A0,D1.W),-(sp)                ; push on our dialog ID

        btst    #2,D0                        ; is this an old style routine?
        beq.s    @HookInMyProcsOldStyle        ; yes, so donUt push mondo parms

        move.l    pZeroPoint,-(sp)            ; location
        clr.l    -(sp)                        ; dialog hook
        clr.l    -(sp)                        ; modal dialog filter
        clr.l    -(sp)                        ; active list
        clr.l    -(sp)                        ; activate proc

    @HookInMyProcsOldStyle
        clr.l    -(sp)                        ; your data / modal dialog filter
        add.w    #2,D0                        ; convert selector to Custom/P routine

    @NoConversionNeeded
        move.w    D0,D1                        ; use D1 for table index
        add.w    D1,D1                        ; double for 2 byte table entries

        add.w    #1,D0                        ; make selector 1-base again
        move.w    D0,-(sp)                    ; put the possibly modified selector back

        move.w    D0,gSelector                ; remember selector

        move.l    A7,pParameters                ; remember pointer to all parameters
                                            ; (including the selector)

        lea        pOffsetToDlgHook,A0            ; remember dlgHook
        move.w    (A0,D1.W),D0
        move.l    (A7,D0.W),pDlgHook
        lea        DialogHookEntry,A0            ; put in my own
        move.l    A0,(A7,D0.W)

        lea        pOffsetToFileFilter,A0        ; remember fileFilter
        move.w    (A0,D1.W),D0
        bmi.s    @DontSwapFileFilter            ; but only if itUs got one
        move.l    (A7,D0.W),pFileFilter
        tst.l    pFileFilter
        beq.s    @DontSwapFileFilter            ; donUt supply one if he didnUt
        lea        FileFilterEntry,A0            ; put in my own
        move.l    A0,(A7,D0.W)

    @DontSwapFileFilter
        lea        pOffsetToModalFilter,A0        ; remember modalFilter
        move.w    (A0,D1.W),D0
        move.l    (A7,D0.W),pModalFilter
        lea        ModalFilterEntry,A0            ; put in my own
        move.l    A0,(A7,D0.W)

        jsr        MungeNextDialog
        jsr        StartLookingForList
        clr.w    curVRefNum(A4)
        clr.l    curDirID(A4)
        move.w    #-1,prevCell(A4)

        pea        pOldValue                    ; Turn off hotkeys so we donUt
        move.w    #-1,-(sp)                    ; re-enter ourselves by bringing
        jsr        CETurnOnOff                    ; up the MiniFinder.
        add.w    #6,sp

        move.l    gOldStandardFile,A0
        jsr        (A0)

        pea        pOldValue
        move.w    pOldValue,-(sp)
        jsr        CETurnOnOff
        add.w    #6,sp

    @CloseUp
        tst.b    pCloseIt
        beq.s    @continue

        move.w    gRefNum,-(sp)                ; close our resource file
        CloseResFile
        moveq    #-1,D1
        move.w    D1,gRefNum

        bra.s    @continue

    @NoFunnyStuff
        move.l    gOldStandardFile,A0            ; here if we are to call old StdFile with
        jsr        (A0)                        ; ...no tricks.

    @continue
        move.l    pSavedReturnAddress,-(sp)
        move.l    pSavedA4,A4
    }
}


- --
Keith Rollin
Phantom Programmer
Taligent, Inc.

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

From: [e-mail] (Martin Friedrich)
Subject: MacBinary format and empty forks
Organization: University of Oldenburg, Germany
Date: Fri, 29 May 1992 08:04:42 GMT

Hello, Netters !

The defintion of the macbinary format states, that for both the resource and
data fork of the transferred file, null characters are padded to the next
128 byte boundary. But if (one of ) the fork(s) is/are empty, do you have
to insert 128 null characters before the next fork or end of the file,
respectively ?

Thanks in advance,
- --
LLaP
       Martin Friedrich

- -----------------------------------------------------------------------------
                         |"I never will understand
REAL      Martin Friedrich   (CS-Student)    | humans ..."
NICK      jupp                               | -- Spock, Patterns of Force
UUCP      friedrich@uniol                    --------------------------------
DOMAIN    [e-mail]
HOME      Straekweg 1 , 2986 Leezdorf

     Superior abilities breed superior ambitions
- -----------------------------------------------------------------------------

+++++++++++++++++++++++++++

From: [e-mail] (Jack Brindle)
Date: 29 May 92 17:44:42 GMT
Organization: Motorola, Mobile Data Division - Seattle, WA

In article <[e-mail]> [e-mail] (Martin Friedrich) writes:
>Hello, Netters !
>
>The defintion of the macbinary format states, that for both the resource and
>data fork of the transferred file, null characters are padded to the next
>128 byte boundary. But if (one of ) the fork(s) is/are empty, do you have
>to insert 128 null characters before the next fork or end of the file,
>respectively ?

No. Byte counting within the MacBinary format is done with modulo 128
arithmetic. Realizing that zero mod 128 is zero, no null bytes should
be placed either in place of a fork or at the end of a fork that is
a multiple of 128 bytes in length.

If you think about this, you will realize that adding a block of nulls
where the data fork would go would really mess up decoding. The reason
is that the data fork length information in the header indicates no
data. The decoder interprets this to be an actual length of zero, and
does not skip over the block, but procedes to decode the resource fork.
At this point everything is 128 bytes off.

The real reason for the pad nulls is to assure that the two forks start
on nice even boundaries, making things a bit easier when decoding data
coming in through transfer protocols such as XModem. The only catch was
that when Dennis originally defined the standard (MacBinary 1), he placed
the file name in an awkward position - it starts on an ODD byte. For
obvious compatibility reasons, it was not corrected when the MacBinary II
standard was developed.

Jack Brindle
ham radio: wa4fib
internet: [e-mail]

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

From: [e-mail] (Adam King)
Subject: REWARD OFFERED: Think C Multisegment Driver Problem
Date: 30 May 92 04:22:09 GMT
Organization: UCLA Computer Science Department

I'm looking for anybody who has successfully written a multi-segment
driver using ThinkC (5.02) that installs at init time.

The problem I am having with mine is a segment loader system error
when I return from closing the driver.

I have loaded this driver at INIT time using ThinkC's installRAMDriver
code and I am closing it with their removeRAMDriver code.  It crashes
durring the call to PBClose (the driver).

I suspect that the glue on the driver is trying to treat the docd
segments as resources and this is bogus because they have been
detatched.  Is this true?  Is it avoidable?

About the reward:

This has been driving my so insane that I will send a check for $10 to
the person who first sends me info that directly leads to the solution
of my problem.

Adam
- --
*****************************************************
* Looking for Castalia. Tell me if you've found it. *
*****************************************************

+++++++++++++++++++++++++++

From: [e-mail] (Pete Resnick)
Organization: University of Illinois at Urbana
Date: Sat, 30 May 1992 05:39:31 GMT

[e-mail] (Adam King) writes:

>I have loaded this driver at INIT time using ThinkC's installRAMDriver
>code and I am closing it with their removeRAMDriver code.  It crashes
>durring the call to PBClose (the driver).

Eeek!! The code to which you are referring (InstallRAMDriver,
RemoveRAMDriver) was written by me, and quite poorly I might add; it
has some major bugs. It will certainly fail for multi-segment drivers.
I have discovered the problem and made *oodles* of changes to how the
code works works. I would be glad to send you (and other's) new and
working code. If I get enough response, I will post it to an FTP
archive.

Sorry for the trouble you are having.

pr
- --
Pete Resnick             (...so what is a mojo, and why would one be rising?)
Graduate assistant - Philosophy Department, Gregory Hall, UIUC
System manager - Cognitive Science Group, Beckman Institute, UIUC
Internet: [e-mail]

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

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