From a2512226f89cc49cf2684342650c1fcce68a41c5 Mon Sep 17 00:00:00 2001
From: "Ryan X. Charles" <ryan@bitpay.com>
Date: Wed, 13 Aug 2014 18:00:41 -0400
Subject: [PATCH] address convenience functions

---
 lib/address.js       | 11 +++++++++++
 lib/key.js           |  5 +++++
 test/test.address.js | 21 +++++++++++++++++++++
 test/test.key.js     | 14 ++++++++++++++
 4 files changed, 51 insertions(+)

diff --git a/lib/address.js b/lib/address.js
index 798d993..35488bd 100644
--- a/lib/address.js
+++ b/lib/address.js
@@ -1,5 +1,7 @@
 var base58check = require('./base58check');
 var constants = require('./constants');
+var Hash = require('./hash');
+var Pubkey = require('./pubkey');
 
 function Address(hash, network, type) {
   this.hash = hash;
@@ -7,6 +9,15 @@ function Address(hash, network, type) {
   this.type = type;
 };
 
+Address.prototype.fromPubkey = function(pubkey, network, compressed) {
+  if (typeof compressed === 'undefined')
+    compressed = true;
+  this.hash = Hash.sha256ripemd160(pubkey.toDER(compressed));
+  this.network = network || 'mainnet';
+  this.type = 'pubkeyhash';
+  return this;
+};
+
 Address.prototype.fromString = function(str) {
   var buf = base58check.decode(str);
   if (buf.length !== 1 + 20)
diff --git a/lib/key.js b/lib/key.js
index 11e11b2..cefc341 100644
--- a/lib/key.js
+++ b/lib/key.js
@@ -1,3 +1,4 @@
+var Address = require('../lib/address');
 var Privkey = require('./privkey');
 var Pubkey = require('./pubkey');
 var Random = require('./random');
@@ -31,6 +32,10 @@ Key.prototype.fromString = function(str) {
   }
 };
 
+Key.prototype.getAddress = function(network, compressed) {
+  return (new Address()).fromPubkey(this.pubkey, network, compressed);
+};
+
 Key.prototype.privkey2pubkey = function() {
   this.pubkey = new Pubkey(point.getG().mul(this.privkey.bn));
 };
diff --git a/test/test.address.js b/test/test.address.js
index 2bd7002..498d110 100644
--- a/test/test.address.js
+++ b/test/test.address.js
@@ -1,5 +1,6 @@
 var should = require('chai').should();
 var constants = require('../lib/constants');
+var Pubkey = require('../lib/pubkey');
 var Address = require('../lib/address');
 
 describe('address', function() {
@@ -11,6 +12,26 @@ describe('address', function() {
     should.exist(address);
   });
 
+  describe('#fromPubkey', function() {
+
+    it('should make this address from a compressed pubkey', function() {
+      var pubkey = new Pubkey();
+      pubkey.fromDER(new Buffer('0285e9737a74c30a873f74df05124f2aa6f53042c2fc0a130d6cbd7d16b944b004', 'hex'));
+      var address = new Address();
+      address.fromPubkey(pubkey);
+      address.toString().should.equal('19gH5uhqY6DKrtkU66PsZPUZdzTd11Y7ke');
+    });
+
+    it('should make this address from an uncompressed pubkey', function() {
+      var pubkey = new Pubkey();
+      pubkey.fromDER(new Buffer('0285e9737a74c30a873f74df05124f2aa6f53042c2fc0a130d6cbd7d16b944b004', 'hex'));
+      var address = new Address();
+      address.fromPubkey(pubkey, 'mainnet', false);
+      address.toString().should.equal('16JXnhxjJUhxfyx4y6H4sFcxrgt8kQ8ewX');
+    });
+
+  });
+
   describe('#fromString', function() {
     
     it('should derive from this known address string mainnet', function() {
diff --git a/test/test.key.js b/test/test.key.js
index 37a4559..7e21fac 100644
--- a/test/test.key.js
+++ b/test/test.key.js
@@ -1,6 +1,7 @@
 var should = require('chai').should();
 var bn = require('../lib/bn');
 var point = require('../lib/point');
+var Address = require('../lib/address');
 var Privkey = require('../lib/privkey');
 var Pubkey = require('../lib/pubkey');
 var Key = require('../lib/key');
@@ -74,6 +75,19 @@ describe('key', function() {
 
   });
 
+  describe('#getAddress', function() {
+    
+    it('should return an address', function() {
+      var privhex = '906977a061af29276e40bf377042ffbde414e496ae2260bbf1fa9d085637bfff';
+      var pubhex = '02a1633cafcc01ebfb6d78e39f687a1f0995c62fc95f51ead10a02ee0be551b5dc';
+      var key = new Key();
+      key.privkey = new Privkey(bn(new Buffer(privhex, 'hex')));
+      key.privkey2pubkey();
+      key.getAddress().toString().should.equal((new Address()).fromPubkey(key.pubkey).toString());
+    });
+
+  });
+
   describe("#privkey2pubkey", function() {
     
     it('should convert this known Privkey to known Pubkey', function() {