#!/bin/bash

shows() {
	t=$[s/75]; printf "%u sectors" $s
	if [ $1 -ne 0 ]; then printf " (+%u bytes)" $1; fi
	printf "=%02u:%02u.%02u\n" $[t/60] $[t%60] $[s-t*75]
}

if [ "$1" ]
then	if [ -r "$1" ]
	then	if [ -d  "$1" ]
		then	echo "$1: is a directory"
		else	echo "Length info in ISO header: $[$(printf \
			"0x%s%s%s%s" $(head -c$[0100130] $1 | tail -c4 \
			| od -tx1 | head -1 | cut -c9-))] in $1"
			if [ "$(ls -l "$1" | head -c1 2>>/dev/null)" != "b" ]
			then	echo -n "Real length of the file:   "
				l=$(wc -c < $1); s=$[l/2048]; shows $[l%2048] 
			fi
		fi
	else	s="$1"
		s=$((echo $[s]) 2> /dev/null)
		if [ "$s" ] && [ $s -gt 0 ]
		then	shows 0
		else	echo "$1: not readable" 1>&2
		fi
	fi
else	echo	"Usage:	$(basename $0) ISO9660-image" 1>&2
	echo	"or:	$(basename $0) number-of-sectors" 1>&2
	echo	"	(this form is useful when having"
	echo	"	 number of extends from mkisofs)"
	echo	"  (c)	Jerzy Tarasiuk <jt@fuw.edu.pl>"
fi