From 65c3545cb64de6654124dfc9d759de14b2873158 Mon Sep 17 00:00:00 2001
From: "Ryan X. Charles" <ryan@bitpay.com>
Date: Tue, 19 Aug 2014 16:27:28 -0700
Subject: [PATCH] include i in sig obj + cosmetic improvements

---
 lib/signature.js | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/lib/signature.js b/lib/signature.js
index 5dcf3b4..f87215e 100644
--- a/lib/signature.js
+++ b/lib/signature.js
@@ -1,26 +1,31 @@
-var bn = require('./bn');
+var BN = require('./bn');
+var Point = require('./point');
+var Pubkey = require('./pubkey');
 
-var Signature = function Signature(r, s) {
+var Signature = function Signature(r, s, i) {
   if (!(this instanceof Signature))
-    return new Signature(r, s);
+    return new Signature(r, s, i);
+
   this.r = r;
   this.s = s;
+  this.i = i; //public key recovery parameter in range [0, 3]
 };
 
 Signature.prototype.fromCompressed = function(buf) {
-  var b1 = buf.slice(0, 1)[0];
+  var i = buf.slice(0, 1)[0];
   var b2 = buf.slice(1, 33);
   var b3 = buf.slice(33, 65);
 
-  if (!(b1 === 0 || b1 === 1 || b1 === 2 || b1 === 3))
+  if (!(i === 0 || i === 1 || i === 2 || i === 3))
     throw new Error('signature: i must be 0, 1, 2, or 3');
   if (b2.length !== 32)
     throw new Error('signature: r must be 32 bytes');
   if (b3.length !== 32)
     throw new Error('signature: s must be 32 bytes');
 
-  this.r = bn.fromBuffer(b2);
-  this.s = bn.fromBuffer(b3);
+  this.i = i;
+  this.r = BN().fromBuffer(b2);
+  this.s = BN().fromBuffer(b3);
 };
 
 Signature.prototype.fromDER = function(buf) {
@@ -53,7 +58,7 @@ Signature.parseDER = function(buf) {
 
   var rlength = buf[2 + 1];
   var rbuf = buf.slice(2 + 2, 2 + 2 + rlength);
-  var r = bn.fromBuffer(rbuf);
+  var r = BN().fromBuffer(rbuf);
   var rneg = buf[2 + 1 + 1] === 0x00 ? true : false;
   if (rlength !== rbuf.length)
     throw new Error('signature: Length of r incorrect');
@@ -64,7 +69,7 @@ Signature.parseDER = function(buf) {
 
   var slength = buf[2 + 2 + rlength + 1];
   var sbuf = buf.slice(2 + 2 + rlength + 2, 2 + 2 + rlength + 2 + slength);
-  var s = bn.fromBuffer(sbuf);
+  var s = BN().fromBuffer(sbuf);
   var sneg = buf[2 + 2 + rlength + 2 + 2] === 0x00 ? true : false;
   if (slength !== sbuf.length)
     throw new Error('signature: Length of s incorrect');
@@ -92,7 +97,8 @@ Signature.parseDER = function(buf) {
 };
 
 Signature.prototype.toCompressed = function(i) {
-  if (!(i === 0 || i === 1 || i ===2 || i ===3))
+  i = typeof i === 'number' ? i : this.i;
+  if (!(i === 0 || i === 1 || i === 2 || i === 3))
     throw new Error('signature: i must be equal to 0, 1, 2, or 3');
   
   var b1 = new Buffer([i]);