Initial data commit

Task/Canonicalize-CIDR/JavaScript/canonicalize-cidr.js

@@ -0,0 +1,50 @@
+const canonicalize = s => {
+
+    // Prepare a DataView over a 16 Byte Array buffer.
+    // Initialised to all zeros.
+    const dv = new DataView(new ArrayBuffer(16));
+
+    // Get the ip-address and cidr components
+    const [ip, cidr] = s.split('/');
+
+    // Make sure the cidr component is a usable int, and
+    // default to 32 if it does not exist.
+    const cidrInt = parseInt(cidr || 32, 10);
+
+    // Populate the buffer with uint8 ip address components.
+    // Use zero as the default for shorthand pool definitions.
+    ip.split('.').forEach(
+        (e, i) => dv.setUint8(i, parseInt(e || 0, 10))
+    );
+
+    // Grab the whole buffer as a uint32
+    const ipAsInt = dv.getUint32(0);
+
+    // Zero out the lower bits as per the CIDR number.
+    const normIpInt = (ipAsInt >> 32 - cidrInt) << 32 - cidrInt;
+
+    // Plonk it back into the buffer
+    dv.setUint32(0, normIpInt);
+
+    // Read each of the uint8 slots in the buffer and join them with a dot.
+    const canonIp = [...'0123'].map((e, i) => dv.getUint8(i)).join('.');
+
+    // Attach the cidr number to the back of the normalised IP address.
+    return [canonIp, cidrInt].join('/');
+  }
+
+  const test = s => console.log(s, '->', canonicalize(s));
+  [
+    '255.255.255.255/10',
+    '87.70.141.1/22',
+    '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',
+    '10.207.219.251/32',
+    '10.207.219.251',
+    '110.200.21/4',
+    '10..55/8',
+    '10.../8'
+  ].forEach(test)