From e6af57f4faf0c98ddf37418e49b1caea5d762a96 Mon Sep 17 00:00:00 2001
From: "Ryan X. Charles" <ryan@bitpay.com>
Date: Mon, 1 Sep 2014 18:01:17 -0700
Subject: [PATCH] script.toBuffer();

---
 README.md      |  1 +
 lib/script.js  | 30 ++++++++++++++++----
 test/script.js | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 100 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 5711a72..2e0686e 100644
--- a/README.md
+++ b/README.md
@@ -46,3 +46,4 @@ Features over bitcore:
 * Better test coverage
 * Proper message signing and verification
 * npm-shrinkwrap.json ensures npm install works as intended
+* byte-for-byte reading/writing scripts
diff --git a/lib/script.js b/lib/script.js
index 81a4cba..4b56b37 100644
--- a/lib/script.js
+++ b/lib/script.js
@@ -1,4 +1,5 @@
 var BufferReader = require('./bufferreader');
+var BufferWriter = require('./bufferwriter');
 var Opcode = require('./opcode');
 
 var Script = function Script(buf) {
@@ -75,14 +76,33 @@ Script.prototype.fromBuffer = function(buf) {
 Script.prototype.toBuffer = function() {
   var bw = new BufferWriter();
 
-  for (var key in this.chunks) {
-    if (this.chunks.hasOwnProperty(key)) {
-      var chunk = this.chunks[key];
-      if (typeof chunk === 'number') {
-        
+  for (var i = 0; i < this.chunks.length; i++) {
+    var chunk = this.chunks[i];
+    if (typeof chunk === 'number') {
+      var opcodenum = chunk;
+      bw.writeUInt8(opcodenum);
+    } else {
+      var opcodenum = chunk.opcodenum;
+      bw.writeUInt8(chunk.opcodenum);
+      if (opcodenum < Opcode.map.OP_PUSHDATA1) {
+        bw.write(chunk.buf);
+      }
+      else if (opcodenum === Opcode.map.OP_PUSHDATA1) {
+        bw.writeUInt8(chunk.len);
+        bw.write(chunk.buf);
+      }
+      else if (opcodenum === Opcode.map.OP_PUSHDATA2) {
+        bw.writeUInt16LE(chunk.len);
+        bw.write(chunk.buf);
+      }
+      else if (opcodenum === Opcode.map.OP_PUSHDATA4) {
+        bw.writeUInt32LE(chunk.len);
+        bw.write(chunk.buf);
       }
     }
   }
+
+  return bw.concat();
 };
 
 module.exports = Script;
diff --git a/test/script.js b/test/script.js
index a034675..6f19ba7 100644
--- a/test/script.js
+++ b/test/script.js
@@ -77,4 +77,78 @@ describe('Script', function() {
 
   });
 
+  describe('#toBuffer', function() {
+    
+    it('should output this buffer containing an OP code', function() {
+      var buf = new Buffer(1);
+      buf[0] = Opcode('OP_0').toNumber();
+      var script = Script().fromBuffer(buf);
+      script.chunks.length.should.equal(1);
+      script.chunks[0].should.equal(buf[0]);
+      script.toBuffer().toString('hex').should.equal(buf.toString('hex'));
+    });
+
+    it('should output this buffer containing another OP code', function() {
+      var buf = new Buffer(1);
+      buf[0] = Opcode('OP_CHECKMULTISIG').toNumber();
+      var script = Script().fromBuffer(buf);
+      script.chunks.length.should.equal(1);
+      script.chunks[0].should.equal(buf[0]);
+      script.toBuffer().toString('hex').should.equal(buf.toString('hex'));
+    });
+
+    it('should output this buffer containing three bytes of data', function() {
+      var buf = new Buffer([3, 1, 2, 3]);
+      var script = Script().fromBuffer(buf);
+      script.chunks.length.should.equal(1);
+      script.chunks[0].buf.toString('hex').should.equal('010203');
+      script.toBuffer().toString('hex').should.equal(buf.toString('hex'));
+    });
+
+    it('should output this buffer containing OP_PUSHDATA1 and three bytes of data', function() {
+      var buf = new Buffer([0, 0, 1, 2, 3]);
+      buf[0] = Opcode('OP_PUSHDATA1').toNumber();
+      buf.writeUInt8(3, 1);
+      var script = Script().fromBuffer(buf);
+      script.chunks.length.should.equal(1);
+      script.chunks[0].buf.toString('hex').should.equal('010203');
+      script.toBuffer().toString('hex').should.equal(buf.toString('hex'));
+    });
+
+    it('should output this buffer containing OP_PUSHDATA2 and three bytes of data', function() {
+      var buf = new Buffer([0, 0, 0, 1, 2, 3]);
+      buf[0] = Opcode('OP_PUSHDATA2').toNumber();
+      buf.writeUInt16LE(3, 1);
+      var script = Script().fromBuffer(buf);
+      script.chunks.length.should.equal(1);
+      script.chunks[0].buf.toString('hex').should.equal('010203');
+      script.toBuffer().toString('hex').should.equal(buf.toString('hex'));
+    });
+
+    it('should output this buffer containing OP_PUSHDATA4 and three bytes of data', function() {
+      var buf = new Buffer([0, 0, 0, 0, 0, 1, 2, 3]);
+      buf[0] = Opcode('OP_PUSHDATA4').toNumber();
+      buf.writeUInt16LE(3, 1);
+      var script = Script().fromBuffer(buf);
+      script.chunks.length.should.equal(1);
+      script.chunks[0].buf.toString('hex').should.equal('010203');
+      script.toBuffer().toString('hex').should.equal(buf.toString('hex'));
+    });
+
+    it('should output this buffer an OP code, data, and another OP code', function() {
+      var buf = new Buffer([0, 0, 0, 0, 0, 0, 1, 2, 3, 0]);
+      buf[0] = Opcode('OP_0').toNumber();
+      buf[1] = Opcode('OP_PUSHDATA4').toNumber();
+      buf.writeUInt16LE(3, 2);
+      buf[buf.length - 1] = Opcode('OP_0').toNumber();
+      var script = Script().fromBuffer(buf);
+      script.chunks.length.should.equal(3);
+      script.chunks[0].should.equal(buf[0]);
+      script.chunks[1].buf.toString('hex').should.equal('010203');
+      script.chunks[2].should.equal(buf[buf.length - 1]);
+      script.toBuffer().toString('hex').should.equal(buf.toString('hex'));
+    });
+
+  });
+
 });