Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!wuarchive!waikato.ac.nz!canterbury!phys169
From: phys169@csc.canterbury.ac.nz
Newsgroups: comp.lang.pascal
Subject: Re: FILES and pointers
Message-ID: <1991Apr22.153127.499@csc.canterbury.ac.nz>
Date: 22 Apr 91 03:31:27 GMT
References: <1991Apr22.014013.7390@usenet.ins.cwru.edu>
Organization: University of Canterbury, Christchurch, New Zealand
Lines: 25

In article <1991Apr22.014013.7390@usenet.ins.cwru.edu>, wct@po.CWRU.Edu (William C. Thompson) writes:
> 
> Say I want to save a dynamically sized structure....
> The problem is that I need to save this to disk so that it can
> be recalled as quickly as possible. 

If you use Turbo Pascal, the most efficient method is simply an untyped file, 
and use blockwrite to output the appropriate number of bytes, e.g.

type BufferType = array[1..65520] of byte;
var BufferPtr : ^BufferType;
    MyFyle    : file;
begin
assign(MyFyle,'something'); rewrite(MyFile,1);
getmem(BufferPtr,some-number);
blockwrite(MyFyle,BufferPtr^,some-number);
end.

In generic Pascal, you might have to either issue many writes (e.g. FILE OF 
CHAR) or write too much (e.g. FILE OF BUFFER, where bufferptr was declared as 
a pointer to type Buffer), it all depends on the implementation's enhancements
if you're after efficiency.

Hope this helps,
Mark Aitchison.