Use `compact-encoding-net` for encoding IPs (#33)

* Use `compact-encoding-net` for encoding IPs

* Feedback from @mafintosh

.gitignore

@@ -1,4 +1,5 @@
 node_modules
+package-lock.json
 sandbox.js
 sandbox
 coverage

lib/peer.js

@@ -1,49 +1,27 @@
 const sodium = require('sodium-universal')
 const c = require('compact-encoding')
-
-const addr = Buffer.alloc(6)
-let i = 0
+const net = require('compact-encoding-net')
 
 const ipv4 = {
-  preencode (state, p) {
-    state.end += 6
-  },
-  encode (state, p) {
-    i = 0
-    state.buffer[state.start++] = num(p.host)
-    state.buffer[state.start++] = num(p.host)
-    state.buffer[state.start++] = num(p.host)
-    state.buffer[state.start++] = num(p.host)
-    state.buffer[state.start++] = p.port
-    state.buffer[state.start++] = p.port >>> 8
-  },
+  ...net.ipv4Address,
   decode (state) {
-    if (state.end - state.start < 6) throw new Error('Out of bounds')
+    const ip = net.ipv4Address.decode(state)
     return {
-      id: null, // populated elsewhere
-      host: state.buffer[state.start++] + '.' + state.buffer[state.start++] + '.' + state.buffer[state.start++] + '.' + state.buffer[state.start++],
-      port: state.buffer[state.start++] + 256 * state.buffer[state.start++]
+      id: null, // populated by the callee
+      host: ip.host,
+      port: ip.port
     }
   }
 }
 
 module.exports = { id, ipv4, ipv4Array: c.array(ipv4) }
 
-function num (ip) {
-  let n = 0
-  let c = 0
-  while (i < ip.length && (c = ip.charCodeAt(i++)) !== 46) n = n * 10 + (c - 48)
-  return n
-}
-
-function id (ip, port, out = Buffer.allocUnsafe(32)) {
-  i = 0
-  addr[0] = num(ip)
-  addr[1] = num(ip)
-  addr[2] = num(ip)
-  addr[3] = num(ip)
-  addr[4] = port
-  addr[5] = port >>> 8
+function id (host, port, out = Buffer.allocUnsafe(32)) {
+  const addr = out.subarray(0, 6)
+  ipv4.encode(
+    { start: 0, end: 6, buffer: addr },
+    { host, port }
+  )
   sodium.crypto_generichash(out, addr)
   return out
 }

package.json

@@ -6,6 +6,7 @@
   "dependencies": {
     "bind-easy": "^1.0.0",
     "compact-encoding": "^2.1.0",
+    "compact-encoding-net": "^1.0.1",
     "fast-fifo": "^1.0.0",
     "kademlia-routing-table": "^1.0.0",
     "nat-sampler": "^1.0.1",