#
# $Id: binary-io.tcl,v 1.1 1993/12/10 17:55:12 loverso Exp loverso $
#

if 0 {
Message-ID: <09Nov93.135824@LoVerso.Southborough.MA.US>
From: John Robert LoVerso <John@LoVerso.Southborough.MA.US>
References:  <2bm6mr$oei@wupost.wustl.edu>
Subject: Re: Reading binary data containing nulls
Organization: John & Sue's House, Southborough MA

bergeron%fcrc-next.ecs.wustl.edu (Timothy Bergeron) writes:
|> Is there a way to get tcl to read in binary data that contains nulls ?

Here is a "portable" (TCL-only) solution.  It is anything but fast and
convenient.  However, if the bulk of your data is handled by direct reads,
this may be just fine for you.  I wrote this for a TELNET client and it
was sufficient for the job.

John
}

#
# Copyright 1993, John Robert LoVerso
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose and without fee is hereby granted, provided
# that the above copyright notice appear in all copies.  The author makes
# no representations about the suitability of this software for any purpose.
# It is provided "as is" without express or implied warranty.
#

#
# Cheapo "Binary I/O package"
#

proc PutByte { fid val } {
	if {$val > 0} {
		puts -nonewline $fid [ format "%c" $val ]
	} else {
		# maybe use "echo -n x" or "echo x\\c" instead of shell printf
		exec >@ $fid sh -c "printf x | tr x \\\\000"
	}
}
proc PutBytes { fid args } {
	foreach b $args {
		PutByte $fid $b
	}
}

proc GetByte { fid } {
	set byte [read $fid 1]
	if {[string length $byte] == 1} {
		scan $byte "%c" val
		return $val
	} else {
		if [eof $fid] {return -1} else {return 0}
	}
}