is_private


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#!/usr/bin/env zsh
typeset -ga PRIVATE_RANGES=(
    00001010           # 10.0.0.0/8
    101011000001       # 172.16.0.0/12
    1100000010101000   # 192.168.0.0/16
)

test_range() {
    typeset net addr=$(printf '%.2x' ${(s:.:)1})
    for net in $PRIVATE_RANGES; do
        ((16#$addr >> (32 - $#net) == 2#$net)) && return 0
    done
}

report() {
    typeset result='private' addr=$1 state=$2
    ((state)) && result='not private'
    printf "%s is %s\n" $addr $result
    exit $state
}

main() {
    test_range $1 && report $1 0
    report $1 1
}

main $@