Shell Programming and Scripting

#! /usr/bin/ksh
typeset -R1 dig
typeset -i8 octal
typeset -Z4 result

#
#  handle sign

number=$1
sign="C"
if ((number<0)) ; then
        ((number=-number))
        sign="D"
fi


#
#  prepend a zero if needed

((ilength=${#number}))
if ((ilength/2*2 == ilength)) ; then
        number=0${number}
        ((ilength=${#number}))
fi

#
#  conversion loop

((olength=ilength/2))
packswitch=1
char2=$sign
while ((ilength)) ; do
        dig=$number
        ((ilength=ilength-1))
        typeset -L$ilength newnumber=$number
        number=$newnumber
        if ((packswitch)) ; then
                char1=$dig
                octal=16#${char1}${char2}
                result=${octal#??}
                echo packing $olength $char1 $char2 $octal $result
                output[olength]=$(print -n \\${result})
                ((olength=olength-1))

        else
                char2=$dig
        fi
        ((packswitch=!packswitch))
done

#
#  output the packed decimal to prove it worked

olength=${#output[*]}
o=0
while ((o <= olength)) ; do
        print -n ${output[o]} | od -t x1
        ((o=o+1))
done

exit 0

$ cat x
#! /usr/bin/ksh
high5=$(print -n \\0377\\0377\\0377\\0377\\0377)
typeset -Z5 total
total=123
print -n ${high5}${total} | od -t x1
$  ./x
0000000   ff  ff  ff  ff  ff  30  30  31  32  33
0000012
$