Add tests for script.toASM() and new method script.fromASM()

lib/script/script.js

@@ -134,6 +134,48 @@ Script.prototype.toBuffer = function() {
   return bw.concat();
 };
 
+Script.fromASM = function(str) {
+  var script = new Script();
+  script.chunks = [];
+
+  var tokens = str.split(' ');
+  var i = 0;
+  while (i < tokens.length) {
+    var token = tokens[i];
+    var opcode = Opcode(token);
+    var opcodenum = opcode.toNumber();
+
+    if (_.isUndefined(opcodenum)) {
+      var buf = new Buffer(tokens[i], 'hex');
+      script.chunks.push({
+        buf: buf,
+        len: buf.length,
+        opcodenum: buf.length
+      });
+      i = i + 1;
+    } else if (opcodenum === Opcode.OP_PUSHDATA1 ||
+      opcodenum === Opcode.OP_PUSHDATA2 ||
+      opcodenum === Opcode.OP_PUSHDATA4) {
+      script.chunks.push({
+        buf: new Buffer(tokens[i + 2], 'hex'),
+        len: parseInt(tokens[i + 1]),
+        opcodenum: opcodenum
+      });
+      i = i + 3;
+    } else {
+      script.chunks.push({
+        opcodenum: opcodenum
+      });
+      i = i + 1;
+    }
+  }
+  return script;
+};
+
+Script.fromHex = function(str) {
+  return new Script(new buffer.Buffer(str, 'hex'));
+};
+
 Script.fromString = function(str) {
   if (JSUtil.isHexa(str) || str.length === 0) {
     return new Script(new buffer.Buffer(str, 'hex'));

test/script/script.js

@@ -159,6 +159,19 @@ describe('Script', function() {
 
   });
 
+  describe('#fromASM', function() {
+    it('should parse this known script in ASM', function() {
+      var asm = 'OP_DUP OP_HASH160 f4c03610e60ad15100929cc23da2f3a799af1725 OP_EQUALVERIFY OP_CHECKSIG';
+      var script = Script.fromASM(asm);
+      script.chunks[0].opcodenum.should.equal(Opcode.OP_DUP);
+      script.chunks[1].opcodenum.should.equal(Opcode.OP_HASH160);
+      script.chunks[2].opcodenum.should.equal(20);
+      script.chunks[2].buf.toString('hex').should.equal('f4c03610e60ad15100929cc23da2f3a799af1725');
+      script.chunks[3].opcodenum.should.equal(Opcode.OP_EQUALVERIFY);
+      script.chunks[4].opcodenum.should.equal(Opcode.OP_CHECKSIG);
+    });
+  });
+
   describe('#fromString', function() {
 
     it('should parse these known scripts', function() {
@@ -191,6 +204,11 @@ describe('Script', function() {
       script.toString().toString('hex').should.equal('OP_0 OP_PUSHDATA4 3 0x010203 OP_0');
     });
 
+    it('should output this known script as ASM', function() {
+      var script = Script.fromHex('76a914f4c03610e60ad15100929cc23da2f3a799af172588ac');
+      script.toASM().should.equal('OP_DUP OP_HASH160 f4c03610e60ad15100929cc23da2f3a799af1725 OP_EQUALVERIFY OP_CHECKSIG');
+    });
+
   });
 
   describe('toHex', function() {