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From: souka@uh.msc.umn.edu (Omar Souka)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Resource Fork data storage--related question
Message-ID: <2172@uc.msc.umn.edu>
Date: 19 Jul 90 20:05:32 GMT
References: <1990Jul17.172044.20361@Neon.Stanford.EDU> <1715MAYER-A@RICEVM1>
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> WELL,
> 
> I have a related question. It may be more of a Pascal question than a
> Macintosh question, though.  I would like to retrieve the contents
> of a (rather long) array.  A resource of my own type seems
> like a logical structure for this.
> 
> I know how to load a resource into memory, but I don't see how then to
> store the contents into an array I've declared...
> 
> I would appreciate any suggestions or better ideas.  Thanks!
> 
>     --David

The resource fork is a great place to store nearly any type of data. 
Here is a sketch of what many programs do.

1.  Create a new resource in Resedit.  It doesn't have to have anything
in it right now but a name (try to make the name unique) and a resource number.

Writing to the resource.

1.  Call GetResource to get a handle to your resource.

2.  If its the first time that your writing to it, you must call
SizeHandle to increase the size of the handle to the size of whatever
you are going to store.

3.  Then simply BlockMove the contents of your data structure into the
resource.  In C, it would look something like this:

	BlockMove(array,*ResourceHandle,number_of_bytes);
			or generically
	BlockMove(source pointer, destination pointer, # of bytes)

This operation will stick the raw bytes of your array into your resource.

4.  Call ChangedResource

5.  Call WriteResource

Reading from the resource

1.  Call GetResource

2.  If you need to know how big the handle is call HandleSize

3.  BlockMove from the resource into your array

	BlockMove(*ResourceHandle,array,number_of_bytes);

In Pascal it would look something like this (just a guess, I don't do Pascal)

	BlockMove(ResourceHandle^,@array,number_of_bytes)

What's great about this technique is that you can store very complicated
data structures this way and not really worry about what the structure
looks like.  If anyone is interested in seeing some actual source, just
E-Mail me.