Data commit

Task/Canonicalize-CIDR/UNIX-Shell/canonicalize-cidr.sh

@@ -0,0 +1,45 @@
+function inet_aton {
+  typeset -i addr byte
+  typeset -a bytes
+  if [[ -n $BASH_VERSION ]]; then
+    IFS=. read -a bytes <<<"$1"
+  elif [[ -n $ZSH_VERSION ]]; then
+    IFS=. bytes=($=1)
+  else
+    IFS=. bytes=($1)
+  fi
+  addr=0
+  for byte in "${bytes[@]}"; do
+    (( addr = 256 * addr + byte ))
+  done
+  printf '%s\n' "$addr"
+}
+
+function inet_ntoa {
+  typeset -i addr=$1
+  typeset dotted i
+  for (( i=0; i<4; ++i )); do
+    dotted=$(( addr & 255 ))${dotted:+.$dotted}
+    (( addr >>= 8 ))
+  done
+  printf '%s\n' "$dotted"
+}
+
+function canonicalize_cidr {
+  typeset ip prefix fixed
+  typeset -i netmask  addr
+  while (( $# )); do
+    IFS=/ read ip prefix <<<"$1"
+    netmask=$(( (-1 << (32-prefix)) & -1 ))
+    addr=$(inet_aton "$ip")
+    fixed=$(( addr & netmask ))
+    printf '%s/%s\n' "$(inet_ntoa $fixed)" "$prefix"
+    shift
+  done
+}
+
+# demo code
+if (( ! $# )); then
+  set -- 36.18.154.103/12 62.62.197.11/29 67.137.119.181/4 161.214.74.21/24 184.232.176.184/18
+fi
+canonicalize_cidr "$@"