Added namehash to utils.

Author: ricmoo

utils/index.js

@@ -8,6 +8,7 @@ var bigNumber = require('./bignumber');
 var contractAddress = require('./contract-address');
 var convert = require('./convert');
 var keccak256 = require('./keccak256');
+var namehash = require('./namehash');
 var sha256 = require('./sha2').sha256;
 var randomBytes = require('./random-bytes');
 var properties = require('./properties');
@@ -40,6 +41,8 @@ module.exports = {
     toUtf8Bytes: utf8.toUtf8Bytes,
     toUtf8String: utf8.toUtf8String,
 
+    namehash: namehash,
+
     getAddress: address.getAddress,
     getContractAddress: contractAddress.getContractAddress,
 

utils/namehash.js

@@ -0,0 +1,38 @@
+'use strict';
+
+var convert = require('./convert');
+var utf8 = require('./utf8');
+var keccak256 = require('./keccak256');
+
+var Zeros = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
+var Partition = new RegExp("^((.*)\\.)?([^.]+)$");
+var UseSTD3ASCIIRules = new RegExp("^[a-z0-9.-]*$");
+
+function namehash(name, depth) {
+    name = name.toLowerCase();
+
+    // Supporting the full UTF-8 space requires additional (and large)
+    // libraries, so for now we simply do not support them.
+    // It should be fairly easy in the future to support systems with
+    // String.normalize, but that is future work.
+    if (!name.match(UseSTD3ASCIIRules)) {
+        throw new Error('contains invalid UseSTD3ASCIIRules characters');
+    }
+
+    var result = Zeros;
+    var processed = 0;
+    while (name.length && (!depth || processed < depth)) {
+        var partition = name.match(Partition);
+        var label = utf8.toUtf8Bytes(partition[3]);
+        result = keccak256(convert.concat([result, keccak256(label)]));
+
+        name = partition[2] || '';
+
+        processed++;
+    }
+
+    return convert.hexlify(result);
+}
+
+module.exports = namehash;
+

utils/package.json

@@ -1,6 +1,6 @@
 {
   "name": "ethers-utils",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "description": "Utilities for the Ethers Ethereum library.",
   "bugs": {
     "url": "http://github.com/ethers-io/ethers.js/issues",