Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!charyb!dan
From: dan@kfw.COM (Dan Mick)
Newsgroups: comp.lang.perl
Subject: Binary fixed-length records
Message-ID: <1991Apr23.202307.2454@kfw.COM>
Date: 23 Apr 91 20:23:07 GMT
Reply-To: dan@kfw.com (Dan Mick)
Organization: KFW Corporation, Newbury Park, CA
Lines: 31

Often, I want to dump a file full of fixed-length records.  The one way I've
been using is

#!/usr/local/bin/perl

$stbuf_def="ccCCCCCCSSII"; 		# unpack codes for struct
$streclen=20;				# length of above in bytes
$/ = 0777;				# slurp in the whole file
$_ = <>;				# into $_

$inputlen = length($_);
$offset = 0;

while ($inputlen > 0) {
	$rec = substr($_, $offset, $streclen);

	<unpack and print $rec>

	$inputlen -= $streclen;
	$offset += $streclen;
}


...but it strikes me that 1) the "slurp in whole file" will fail someday,
and 2) the copy in the substr() can't be efficient.

Anyone willing to take a crack?  (I'm aware that the surrounding goo
might not be as efficient as possible; what I'm mostly worried about are
the two points above).

If I could get the book, I would...