make creation methods class methods

lib/crypto/signature.js

@@ -24,48 +24,55 @@ Signature.prototype.set = function(obj) {
   return this;
 };
 
-Signature.prototype.fromCompact = function(buf) {
+Signature.fromCompact = function(buf) {
+  var sig = new Signature();
   var compressed = true;
   var i = buf.slice(0, 1)[0] - 27 - 4;
   //TODO: handle uncompressed pubkeys
-  /*
-  if (i < 0) {
-    compressed = false;
-    i = i + 4;
-  }
-  */
 
   var b2 = buf.slice(1, 33);
   var b3 = buf.slice(33, 65);
 
-  if (!(i === 0 || i === 1 || i === 2 || i === 3))
+  if (!(i === 0 || i === 1 || i === 2 || i === 3)) {
     throw new Error('i must be 0, 1, 2, or 3');
-  if (b2.length !== 32)
+  }
+  if (b2.length !== 32) {
     throw new Error('r must be 32 bytes');
-  if (b3.length !== 32)
+  }
+  if (b3.length !== 32) {
     throw new Error('s must be 32 bytes');
+  }
 
-  this.compressed = compressed;
+  sig.compressed = compressed;
-  this.i = i;
+  sig.i = i;
-  this.r = BN().fromBuffer(b2);
+  sig.r = BN().fromBuffer(b2);
-  this.s = BN().fromBuffer(b3);
+  sig.s = BN().fromBuffer(b3);
 
-  return this;
+  return sig;
 };
 
-Signature.prototype.fromDER = function(buf) {
+Signature.fromDER = function(buf) {
   var obj = Signature.parseDER(buf);
-  this.r = obj.r;
+  var sig = new Signature();
-  this.s = obj.s;
 
-  return this;
+  sig.r = obj.r;
+  sig.s = obj.s;
+
+  return sig;
 };
 
-Signature.prototype.fromString = function(str) {
+// The format used in a tx
-  var buf = new Buffer(str, 'hex');
+Signature.fromTxFormat = function(buf) {
-  this.fromDER(buf);
+  var nhashtype = buf.readUInt8(buf.length - 1);
+  var derbuf = buf.slice(0, buf.length - 1);
+  var sig = new Signature.fromDER(derbuf, false);
+  sig.nhashtype = nhashtype;
+  return sig;
+};
 
-  return this;
+Signature.fromString = function(str) {
+  var buf = new Buffer(str, 'hex');
+  return Signature.fromDER(buf);
 };
 
 Signature.parseDER = function(buf) {

test/crypto/signature.js

@@ -41,8 +41,7 @@ describe('Signature', function() {
         blank,
         blank
       ]);
-      var sig = new Signature();
+      var sig = new Signature.fromCompact(compressed);
-      sig.fromCompact(compressed);
       sig.r.cmp(0).should.equal(0);
       sig.s.cmp(0).should.equal(0);
     });
@@ -54,8 +53,7 @@ describe('Signature', function() {
     var buf = new Buffer('3044022075fc517e541bd54769c080b64397e32161c850f6c1b2b67a5c433affbb3e62770220729e85cc46ffab881065ec07694220e71d4df9b2b8c8fd12c3122cf3a5efbcf2', 'hex');
 
     it('should parse this DER format signature', function() {
-      var sig = new Signature();
+      var sig = new Signature.fromDER(buf);
-      sig.fromDER(buf);
       sig.r.toBuffer({
         size: 32
       }).toString('hex').should.equal('75fc517e541bd54769c080b64397e32161c850f6c1b2b67a5c433affbb3e6277');
@@ -71,8 +69,7 @@ describe('Signature', function() {
     var buf = new Buffer('3044022075fc517e541bd54769c080b64397e32161c850f6c1b2b67a5c433affbb3e62770220729e85cc46ffab881065ec07694220e71d4df9b2b8c8fd12c3122cf3a5efbcf2', 'hex');
 
     it('should parse this DER format signature in hex', function() {
-      var sig = new Signature();
+      var sig = new Signature.fromString(buf.toString('hex'));
-      sig.fromString(buf.toString('hex'));
       sig.r.toBuffer({
         size: 32
       }).toString('hex').should.equal('75fc517e541bd54769c080b64397e32161c850f6c1b2b67a5c433affbb3e6277');
@@ -83,6 +80,25 @@ describe('Signature', function() {
 
   });
 
+  describe('#fromTxFormat', function() {
+
+    it('should convert from this known tx-format buffer', function() {
+      var buf = new Buffer('30450221008bab1f0a2ff2f9cb8992173d8ad73c229d31ea8e10b0f4d4ae1a0d8ed76021fa02200993a6ec81755b9111762fc2cf8e3ede73047515622792110867d12654275e7201', 'hex');
+      var sig = Signature.fromTxFormat(buf);
+      sig.r.toString().should.equal('63173831029936981022572627018246571655303050627048489594159321588908385378810');
+      sig.s.toString().should.equal('4331694221846364448463828256391194279133231453999942381442030409253074198130');
+      sig.nhashtype.should.equal(Signature.SIGHASH_ALL);
+    });
+
+    it('should parse this known signature and rebuild it', function() {
+      var hex = "3044022007415aa37ce7eaa6146001ac8bdefca0ddcba0e37c5dc08c4ac99392124ebac802207d382307fd53f65778b07b9c63b6e196edeadf0be719130c5db21ff1e700d67501";
+      var buf = new Buffer(hex, 'hex');
+      var sig = Signature.fromTxFormat(buf);
+      sig.toTxFormat().toString('hex').should.equal(hex);
+    });
+
+  });
+
   describe('#parseDER', function() {
 
     it('should parse this signature generated in node', function() {