Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Macintosh handles
Keywords: handle, TextEdit, FSWrite
Message-ID: <8043@hoptoad.uucp>
Date: 18 Jul 89 22:06:07 GMT
References: <1044@clinet.FI>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Distribution: comp.sys.mac.programmer
Organization: Eclectic Software, San Francisco
Lines: 40

In article <1044@clinet.FI> maa@clinet.FI (Miika Asunta) writes:
>1)	What is the best way to allocate a chain without fragmenting the
>	memory? Using handles is not as simple as you might think at first
>	- You need to allocate master pointers with MOREMASTERS for all your
>	handles in the main datasegment (#1), and you won't know the amount
>	of handles in a chain forehand. I know that when all of them are
>	in use system calls moremasters again to allocate more pointers, but
>	it can fragment memory!

The recommended way to do this is to determine your master pointer
requirements empirically.  This is described in Tech Note #53.
Briefly, exercise your program thoroughly, then break into MacsBug and
count the number of master pointer blocks.  These are the NON-relocatable
blocks of size $108, $10c, or $110 bytes.  Then add calls to MoreMasters
in The initialization code in CODE 1 to create this many master pointer
blocks plus 20%.  It would probably also be wise to scale this number
according to the amount of available memory.

The Tech Note used to have a note about a dynamic master pointer
allocation technique used by ResEdit that was better, which was
supposed to be the subject of a future Tech Note, but this comment is
no longer present in the current Tech Note #53.  Presumably, it wasn't
that great a technique after all.

>2)	How can I store a TEstylehandle entirely into a file? Is
>	the following (written in pseudo-code) enough:
>	FSWrite n bytes , pointer (TEstylehandle^)

That's just about correct, yes.  In C, actual code would be:
FSWrite(refnum, (long)(*te)->teLength, *((*te)->hText));
and if my Pascal hasn't gotten too rusty, that would be:
FSWrite(refnum, te^^.teLength, (te^^.hText)^);

You can do much the same to read a small text file into a text edit
buffer.
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

"Philosophy is the talk on a cereal box
 Religion is the smile on a dog" -- Edie Brickell, "What I Am"