From 3bc871c02b386392c56e7e81e9f1a2b6bc23a0c4 Mon Sep 17 00:00:00 2001
From: Arcath <adam@arcath.net>
Date: Tue, 26 Jul 2022 21:37:20 +0100
Subject: [PATCH] feat: add parseCDIR function

---
 src/functions/network.spec.ts |  27 +++++++++
 src/functions/network.ts      | 106 ++++++++++++++++++++++++++++++++++
 src/index.ts                  |   1 +
 3 files changed, 134 insertions(+)
 create mode 100644 src/functions/network.spec.ts
 create mode 100644 src/functions/network.ts

diff --git a/src/functions/network.spec.ts b/src/functions/network.spec.ts
new file mode 100644
index 0000000..3cce6d0
--- /dev/null
+++ b/src/functions/network.spec.ts
@@ -0,0 +1,27 @@
+import {parseCDIR} from '../index'
+
+describe('Network', () => {
+  it('should parse', () => {
+    const ip = parseCDIR('10.20.30.40/24')
+
+    expect(ip.ip).toBe('10.20.30.40')
+    expect(ip.bitmask).toBe('24')
+    expect(ip.binary).toBe('00001010000101000001111000101000')
+    expect(ip.binaryMask).toBe('11111111111111111111111100000000')
+    expect(ip.binaryNetwork).toBe('00001010000101000001111000000000')
+    expect(ip.network).toBe('10.20.30.0')
+    expect(ip.mask).toBe('255.255.255.0')
+    expect(ip.binaryBroadcast).toBe('00001010000101000001111011111111')
+    expect(ip.broadcast).toBe('10.20.30.255')
+    expect(ip.first).toBe('10.20.30.1')
+    expect(ip.last).toBe('10.20.30.254')
+    expect(ip.size).toBe(254)
+
+    const smallNetwork = parseCDIR('192.168.1.30/29')
+
+    expect(smallNetwork.mask).toBe('255.255.255.248')
+    expect(smallNetwork.network).toBe('192.168.1.24')
+    expect(smallNetwork.broadcast).toBe('192.168.1.31')
+    expect(smallNetwork.size).toBe(6)
+  })
+})
diff --git a/src/functions/network.ts b/src/functions/network.ts
new file mode 100644
index 0000000..49fc0b5
--- /dev/null
+++ b/src/functions/network.ts
@@ -0,0 +1,106 @@
+const binaryToIp = (binaryIp: string) => {
+  const blocks = [
+    binaryIp.substring(0, 8),
+    binaryIp.substring(8, 16),
+    binaryIp.substring(16, 24),
+    binaryIp.substring(24, 32)
+  ]
+
+  return blocks
+    .map(block => {
+      return parseInt(block, 2)
+    })
+    .join('.')
+}
+
+interface CIDRObject {
+  /** The IP as a binary string */
+  binary: string
+  /** The broadcast address of the network as a binary string */
+  binaryBroadcast: string
+  /** The network mask as a binary string */
+  binaryMask: string
+  /** The network assdress as a binary string */
+  binaryNetwork: string
+  /** The CDIR bitmask */
+  bitmask: string
+  /** The boardcast address as an IP */
+  broadcast: string
+  /** The first IP in the network */
+  first: string
+  /** The ip */
+  ip: string
+  /** The last IP in the network */
+  last: string
+  /** The netmask as an IP */
+  mask: string
+  /** The network IP */
+  network: string
+  /** The number of usable hosts in the network */
+  size: number
+}
+
+/**
+ * Parse an IP in CDIR notation
+ *
+ * @param cdir An IP in CDIR notation e.g. 10.20.30.40/24
+ * @returns An instance of `CDIRObject`
+ */
+export const parseCDIR = (cdir: string): CIDRObject => {
+  const [ip, bitmask] = cdir.split('/')
+
+  const binary = ip
+    .split('.')
+    .map(block => {
+      return parseInt(block, 10).toString(2).padStart(8, '0')
+    })
+    .join('')
+
+  const binaryMask = ''.padStart(parseInt(bitmask, 10), '1').padEnd(32, '0')
+
+  const binaryNetwork = binary
+    .split('')
+    .map((bit, i) => {
+      if (binaryMask[i] === '1') {
+        return bit
+      }
+
+      return '0'
+    })
+    .join('')
+
+  const binaryBroadcast = binary
+    .split('')
+    .map((bit, i) => {
+      if (binaryMask[i] === '1') {
+        return bit
+      }
+
+      return '1'
+    })
+    .join('')
+
+  const broadcast = binaryToIp(binaryBroadcast)
+  const network = binaryToIp(binaryNetwork)
+  const mask = binaryToIp(binaryMask)
+
+  const first = binaryToIp(binaryNetwork.replace(/0$/, '1'))
+  const last = binaryToIp(binaryBroadcast.replace(/1$/, '0'))
+
+  const size = parseInt(binaryBroadcast, 2) - parseInt(binaryNetwork, 2) - 1
+
+  return {
+    binary,
+    binaryBroadcast,
+    binaryMask,
+    binaryNetwork,
+    bitmask,
+    broadcast,
+    first,
+    ip,
+    last,
+    mask,
+    network,
+    size
+  }
+}
diff --git a/src/index.ts b/src/index.ts
index 95b5875..1f5d230 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -42,6 +42,7 @@ export {
 } from './functions/increment'
 export {indexedBy, IndexedArray, IndexedByOptions} from './functions/indexed-by'
 export {keys} from './functions/keys'
+export {parseCDIR} from './functions/network'
 export {mapProperty} from './functions/map-property'
 export {rangeAsString, rangeAsArray} from './functions/range-as-string'
 export {