MacTech 1 to 12/MacTech-vol-1-12.toast/Reference/the cmsp digests ('94-'97)/csmp digest Vol 3 No 104

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From: [e-mail] (Francois Pottier)
Subject: csmp-digest-v3-104
Date: Tue, 11 Jul 1995 13:49:34 +0200 (MET DST)

C.S.M.P. Digest             Tue, 11 Jul 95       Volume 3 : Issue 104

Today's Topics:

        Tools for finding mem. leaks-overwrites
        [Q] How do you create a JFIF file with Quicktime's JPEG?

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>From [e-mail] (Umberto milletti)
Subject: Tools for finding mem. leaks-overwrites
Date: Mon, 19 Jun 1995 22:30:32 GMT
Organization: NETCOM On-line Communication Services (408 261-4700 guest)

I'm looking for tools that will find memory overwrites (out-of-bounds writes
and such), memory leaks and other nasty stuff that's hard to track down without
good tools.  Other tools I've used in the past that fit this bill are purify/
quantify from Pure, and Boundschecker from NuMega, but I don't think either
has a mac version.
We're kind of desperate, trying to track down a nasty overwrite.
Thanks in advance (please send email, as I don't read this all the time),
[e-mail]

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

>From [e-mail] (Jake Hoelter)
Date: Mon, 19 Jun 1995 22:40:08 -0800
Organization: Presage Software

In article <[e-mail]>, [e-mail] (Umberto milletti)
wrote:

>I'm looking for tools that will find memory overwrites (out-of-bounds writes
>and such), memory leaks and other nasty stuff that's hard to track down
without
>good tools.  Other tools I've used in the past that fit this bill are purify/
>quantify from Pure, and Boundschecker from NuMega, but I don't think either
>has a mac version.
>We're kind of desperate, trying to track down a nasty overwrite.

There's two tools that are great to use for tracking down leaks. First is
Metrowerks' ZoneRanger. It comes with CodeWarrior, plus I think they
freely distribute it, so you can download it from wherever. The other tool
is QC from Onyx Technology. QC will let you find overwrites, underwrites,
invalidate memory, do heap stressing (scramble, purge), and a bunch of
other cool stuff.

QC costs about $100.00. You can contact Onyx at [phone]. Or at
[e-mail]. There's a free demo version of QC floating around the
nets somewhere.

Between the two of those tools you can track down most memory problems on
the Mac.

Jake Hoelter
Presage Software
[e-mail]

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

>From [e-mail] (Paddy Benson)
Date: Wed, 21 Jun 1995 13:32:35 +0000
Organization: IONA Technologies

In article <[e-mail]>, [e-mail] (Umberto milletti)
wrote:

> I'm looking for tools that will find memory overwrites (out-of-bounds writes
> and such), memory leaks and other nasty stuff that's hard to track down

MacsBug has a leaks dcmd. This is available on the developer CDs. Also
MacsBug has a built in StepSpy (SS) command to check when a range in
memory changes

Paddy

--
- ---------------------------------------------------------------------
Paddy Benson (IT Design)                email:  [e-mail]
(on contract to...)
IONA Technologies Ltd,                  ftp:    ftp.iona.ie
8-34 Percy Place,                       www:    http://www.iona.ie/
Dublin 4,                               ph:     [phone]
Republic of Ireland.                    fax:    [phone]
- ---------------------------------------------------------------------

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

>From [e-mail] (Jordan Zimmerman)
Date: Wed, 21 Jun 1995 18:10:25 -0800
Organization: Altura Software, Inc.

> I'm looking for tools that will find memory overwrites (out-of-bounds writes
> and such), memory leaks and other nasty stuff that's hard to track down
without
> good tools.  Other tools I've used in the past that fit this bill are purify/
> quantify from Pure, and Boundschecker from NuMega, but I don't think either
> has a mac version.
> We're kind of desperate, trying to track down a nasty overwrite.
> Thanks in advance (please send email, as I don't read this all the time),
> [e-mail]

QC (fron Qnyx Technologies), DoubleTrouble & DisposeResource (on Apple
Developer CD, etc.), Jasik's Debugger - to name a few.

--
Jordan Zimmerman, Altura Software
home page: http://www.altura.com/jordanz/home.html
Who is John Galt?

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

>From [e-mail] (Mike Cohen)
Date: Thu, 22 Jun 1995 23:33:12 GMT
Organization: ISIS International

[e-mail] (Jordan Zimmerman) writes:

>QC (fron Qnyx Technologies), DoubleTrouble & DisposeResource (on Apple
>Developer CD, etc.), Jasik's Debugger - to name a few.

Do you know of anything similar to QC for windoze? I'm trying to debug a
memory overwrite problem in some mac code ported to Visual C++.
--
Mike Cohen - [e-mail]
Home Page: ftp://ftp.netcom.com/pub/is/isis/home.html
PUSH THE BUTTON... SOMEONE

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

>From [e-mail] (Jordan Zimmerman)
Date: Fri, 23 Jun 1995 09:48:50 -0800
Organization: Altura Software, Inc.

> In article <[e-mail]>, [e-mail] (Umberto milletti)
> wrote:
>
> > I'm looking for tools that will find memory overwrites (out-of-bounds writes
> > and such), memory leaks and other nasty stuff that's hard to track down
>
> MacsBug has a leaks dcmd. This is available on the developer CDs. Also
> MacsBug has a built in StepSpy (SS) command to check when a range in
> memory changes
>

In addition to the commercial/freeware tools out there, I usually build
leak checking into my code directly.  Using the C preprocessor, you define
all memory allocation routines to shells that record the allocation.  eg.

    #define NewHandle(size)     RecordNewHandle(size, __FILE__, __LINE__)
    #define DisposeHandle(h)    RecordDisposeHandle(h)

So, RecordNewHandle calls NewHandle, saves the handle in an array (also
saving which file and line it came from).  RecordDisposeHandle removes the
allocation from the array.  At the end of the program, if you have
allocations left in your array, there's a leak.  You can use the saved
file name and line number to find where it was allocated.

This method takes some time to implement (there are a _lot_ of potential
allocators), but in the end is really useful.  Also, having the info can
be used for finding memory corruption, etc.

--
Jordan Zimmerman, Altura Software
home page: http://www.altura.com/jordanz/home.html
Who is John Galt?

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

>From [e-mail] (Aparajita Fishman)
Date: 25 Jun 1995 02:11:47 GMT
Organization: Natural Intelligence, Inc.

> In article <[e-mail]>, [e-mail] (Umberto milletti)
> wrote:
>
> > I'm looking for tools that will find memory overwrites (out-of-bounds writes
> > and such), memory leaks and other nasty stuff that's hard to track down

Contact [e-mail] about their product SmartHeap. It's a
complete replacement for the memory manager which not only does
leak/overwrite detection and so forth, but is also a significantly
faster allocator over time than the allocators that come with any
compiler on the market.


 \_  \_  \_   -----------------------------------------------
 \_\_\_  \_   Aparajita Fishman         [e-mail]
 \_ \__  \_   Software Developer           tel [phone]
 \_  \_  \_   Natural Intelligence, Inc.   fax [phone]

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

>From [e-mail] (David Phillip Oster)
Subject: [Q] How do you create a JFIF file with Quicktime's JPEG?
Date: Mon, 12 Jun 1995 04:34:57 GMT
Organization: Netcom Online Communications Services (408-241-9760 login: guest)


The QuickTime volume of Inside Macintosh sample code that works for making
a PICT file that has a JPEG compressed image.

How do you make a valid file of type JFIF? I've tried just writing the data
from QuickTime's FCompressImage into a file, but programs that know JFIF
say that that isn't a valid JFIF file.

Where is the JFIF file documented?

--
- ------- <mail-to:[e-mail]> ----------
Ahh! The thorazine is wearing off and the odinazine is coming on...

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

>From [e-mail] (David Phillip Oster)
Date: Tue, 13 Jun 1995 00:34:47 GMT
Organization: Netcom Online Communications Services (408-241-9760 login: guest)

In article <[e-mail]> [e-mail] (I) write:

>The QuickTime volume of Inside Macintosh sample code that works for making
>a PICT file that has a JPEG compressed image.

>How do you make a valid file of type JFIF? I've tried just writing the data
>from QuickTime's FCompressImage into a file, but programs that know JFIF
>say that that isn't a valid JFIF file.

>Where is the JFIF file documented?

Well, I pulled out a handy CD-ROM of usenet faqs, and found two ways to
solve my problem:

1.) source code for reading and writing JPEG files.

Free, portable C code for JPEG compression is available from the Independent
JPEG Group.  A package containing our source code,
documentation, and some small test files is available from ftp.uu.net
(192.48.96.9) in directory /graphics/jpeg.  The current release is v5,
file jpegsrc.v5.tar.gz.  You can retrieve this file by FTP or UUCP.
If you are on a PC and don't know how to cope with .tar.gz format, you may
prefer ZIP format, which you can find at Simtel archive sites (see NOTE
above), file msdos/graphics/jpegsrc5.zip.  On CompuServe, see the
GRAPHSUPPORT forum (GO GRAPHSUP), library 15, file jpsrc5.zip.

2.) A kluge that is quick and easy:

[11]  How do I recognize which file format I have, and what do I do about it?

If you have an alleged JPEG file that your software won't read, it's likely
to be HSI format or some other proprietary JPEG-based format.  You can tell
what you have by inspecting the first few bytes of the file:

1.  A JFIF-standard file will start with the four bytes (hex) FF D8 FF E0,
    followed by two variable bytes (often hex 00 10), followed by 'JFIF'.

2.  If you see FF D8 at the start, but not the 'JFIF' marker, you may have a
    "raw JPEG" file.  This is probably decodable as-is by JFIF software ---
    it's worth a try, anyway.

3.  HSI files start with 'hsi1'.  You're out of luck unless you have HSI
    software.  Portions of the file may look like plain JPEG data, but they
    won't decompress properly with non-HSI programs.

4.  A Macintosh PICT file, if JPEG-compressed, will have several hundred
    bytes of header (often 726 bytes, but not always) followed by JPEG data.
    Look for the 3-byte sequence (hex) FF D8 FF --- the text 'Photo - JPEG'
    will usually appear shortly before this header, and 'JFIF' or 'AppleMark'
    will usually appear shortly after it.  Strip off everything before the
    FF D8 FF and you should be able to decode the file.
- -------------
In code, that looks like this:

/* TrimToJFIF - according to the JPEG FAQ, JFIF embedded in Apple starts with
        FF D8 FF
 */
static OSErr TrimToJFIF(Handle  h){
        static char start[] = { 0xFF, 0xD8, 0xFF};
        long    offset, len;

        offset = Munger(h, 0, start, 3, NULL, 0);
        if(offset > 0){
                len = GetHandleSize(h);
                BlockMoveData(*h + offset, *h, len - offset);
                SetHandleSize(h, len - offset);
                return noErr;
        }
        return eJPEGFormatFailure;
}


I've tried it, and it works!
--
- ------- <mail-to:[e-mail]> ----------
Ahh! The thorazine is wearing off and the odinazine is coming on...

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

>From [e-mail] (Lawrence D9Oliveiro)
Date: Tue, 13 Jun 1995 17:41:34 +1200
Organization: University of Waikato

In article <[e-mail]>, [e-mail] (David Phillip
Oster) wrote:

>I've tried just writing the data
>from QuickTime's FCompressImage into a file, but programs that know JFIF
>say that that isn't a valid JFIF file.

That should really be all there is to it. To check that you've written the
data properly, have you tried reading it back and putting it through
FDecompressImage with the same ImageDescriptionhandle?

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

>From [e-mail] (Bas A. Schulte)
Date: Tue, 13 Jun 1995 09:59:22 +0200
Organization: Models, Inc.

In article <[e-mail]>, [e-mail] (David Phillip
Oster) wrote:

> >How do you make a valid file of type JFIF? I've tried just writing the data
> >from QuickTime's FCompressImage into a file, but programs that know JFIF
> >say that that isn't a valid JFIF file.

[stuff deleted]

> static OSErr TrimToJFIF(Handle  h){
>         static char start[] = { 0xFF, 0xD8, 0xFF};
>         long    offset, len;

Hmm, I don't know how solid you want your code to be, but I wouldn't dare
this. To know for sure where the JFIF (hopefully it IS JFIF) part resides
in the PICT, you'd have to fully parse the PICT, scanning through all
opcodes until you find the compressed pixmap part. Quite hard to do.

The way to go is to use FCompressImage (like Lawrence said). I can assure
you that that works. Check your code again. The one thing that might be a
problem is when the user has another JPEG codec installed, or Apple
changes theirs in a future release. There's no garantuee that the stream
output by the codec is JFIF complaint. It will be JPEG, just maybe not
always JFIF.

BTW, Apple's JPEG codec is really really fast...

regards,

Bas Schulte

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

>From Maf Vosburgh <[e-mail]>
Date: 14 Jun 1995 22:56:29 GMT
Organization: MMC

In article <[e-mail]> David Phillip Oster,
[e-mail] writes:
>The QuickTime volume of Inside Macintosh sample code that works for making
>a PICT file that has a JPEG compressed image.
>
>How do you make a valid file of type JFIF? I've tried just writing the data
>from QuickTime's FCompressImage into a file, but programs that know JFIF
>say that that isn't a valid JFIF file.

I enclose some source code that is based on example code written by
Mark Krueger, who wrote the QuickTime Image Compression manager.

It contains the useful proc:
OSErr   WriteJpegData(PicHandle pic, short fileRef);


All you do is
1)Make or open a JPEG compressed PICT
2)Make a new empty file of type JPEG or JFIF.
3)Open it.
4)Call WriteJpegData
5)Close the file.


Maf Vosburgh



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

>From [e-mail] (Yves Piguet)
Date: Fri, 23 Jun 1995 20:07:57 +0200
Organization: Institut d'automatique, EPFL

In article <3rnpet$[e-mail]>, Maf Vosburgh <[e-mail]> wrote:

>In article <[e-mail]> David Phillip Oster,
>[e-mail] writes:
>>How do you make a valid file of type JFIF? I've tried just writing the data
>>from QuickTime's FCompressImage into a file, but programs that know JFIF
>>say that that isn't a valid JFIF file.
>
>I enclose some source code that is based on example code written by
>Mark Krueger, who wrote the QuickTime Image Compression manager.
>
>It contains the useful proc:
>OSErr   WriteJpegData(PicHandle pic, short fileRef);

And how do you *read* a jpeg using QT? One has to create the Image
Description Record,
but how?

Thanks in advance!

Yves Piguet <[e-mail]>
Institut d'automatique               Tel:  [phone]
EPFL                                 Fax:  [phone]
CH - 1015 Lausanne                   Talk, cusm: on request

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

>From [e-mail] (Dale Satterfield)
Date: 26 Jun 1995 15:54:43 GMT
Organization: Apple Computer

In article <[e-mail]>, [e-mail]
(Yves Piguet) wrote:

> In article <3rnpet$[e-mail]>, Maf Vosburgh <[e-mail]> wrote:
>
> >In article <[e-mail]> David Phillip Oster,
> >[e-mail] writes:
> >>How do you make a valid file of type JFIF? I've tried just writing the data
> >>from QuickTime's FCompressImage into a file, but programs that know JFIF
> >>say that that isn't a valid JFIF file.
> >
I had this same problem and was able to write out the file data the QT
created, and then read it back in again with JPEGView, which had no
problem with it. The files were also able to be transfered to a windows
machine and its jpeg viewer was able to open them.

As to reading in a file, you need to create the descriptor first, by
reading the JFIF header. There is sample code out on the net somewhere. I
have lost my directions to it.

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

End of C.S.M.P. Digest
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