From 9ef8b781826eac502783ff74b3dc2949cfc237ed Mon Sep 17 00:00:00 2001
From: Manuel Araoz <manuelaraoz@gmail.com>
Date: Tue, 18 Mar 2014 16:52:34 -0300
Subject: [PATCH] refactor int conversion, encoding, and utils

---
 Script.js                      |   2 +-
 ScriptInterpreter.js           | 101 ++++++---------------------------
 test/test.ScriptInterpreter.js |  19 -------
 test/test.examples.js          |   4 +-
 test/test.util.js              |  32 ++++++++---
 util/util.js                   |  78 ++++++++++++++++++++++++-
 6 files changed, 120 insertions(+), 116 deletions(-)

diff --git a/Script.js b/Script.js
index 873969f..d0abe3a 100644
--- a/Script.js
+++ b/Script.js
@@ -509,7 +509,7 @@ Script.stringToBuffer = function(s) {
         if (!isNaN(integer)) {
           // integer
           //console.log('integer');
-          var data = util.intToBuffer(integer);
+          var data = util.intToBufferSM(integer);
           buf.put(Script.chunksToBuffer([data]));
         } else if (word[0] === '\'' && word[word.length-1] === '\'') {
           // string
diff --git a/ScriptInterpreter.js b/ScriptInterpreter.js
index d1992c7..39a240d 100644
--- a/ScriptInterpreter.js
+++ b/ScriptInterpreter.js
@@ -18,6 +18,9 @@ for (var i in Opcode.map) {
   eval(i + " = " + Opcode.map[i] + ";");
 }
 
+var intToBufferSM = Util.intToBufferSM
+var bufferSMToInt = Util.bufferSMToInt;
+
 function ScriptInterpreter() {
   this.stack = [];
   this.disableUnsafeOpcodes = true;
@@ -120,8 +123,7 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
           case OP_15:
           case OP_16:
             var opint = opcode - OP_1 + 1;
-            var opbuf = bigintToBuffer(opint);
-            console.log('op'+opcode+' = '+opint+', '+buffertools.toHex(opbuf));
+            var opbuf = intToBufferSM(opint);
             this.stack.push(opbuf);
             break;
 
@@ -246,7 +248,7 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
           case OP_DEPTH:
             // -- stacksize
             var value = bignum(this.stack.length);
-            this.stack.push(bigintToBuffer(value));
+            this.stack.push(intToBufferSM(value));
             break;
 
           case OP_DROP:
@@ -355,7 +357,7 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
           case OP_SIZE:
             // (in -- in size)
             var value = bignum(this.stackTop().length);
-            this.stack.push(bigintToBuffer(value));
+            this.stack.push(intToBufferSM(value));
             break;
 
           case OP_INVERT:
@@ -397,9 +399,6 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
             // (x1 x2 - bool)
             var v1 = this.stackTop(2);
             var v2 = this.stackTop(1);
-            console.log('equal');
-            console.log(v1);
-            console.log(v2);
 
             var value = buffertools.compare(v1, v2) === 0;
 
@@ -430,7 +429,7 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
           case OP_NOT:
           case OP_0NOTEQUAL:
             // (in -- out)
-            var num = castBigint(this.stackTop());
+            var num = bufferSMToInt(this.stackTop());
             switch (opcode) {
               case OP_1ADD:
                 num = num.add(bignum(1));
@@ -457,7 +456,7 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
                 num = bignum(num.cmp(0) == 0 ? 0 : 1);
                 break;
             }
-            this.stack[this.stack.length - 1] = bigintToBuffer(num);
+            this.stack[this.stack.length - 1] = intToBufferSM(num);
             break;
 
           case OP_ADD:
@@ -479,11 +478,8 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
           case OP_MIN:
           case OP_MAX:
             // (x1 x2 -- out)
-            var v1 = castBigint(this.stackTop(2));
-            var v2 = castBigint(this.stackTop(1));
-            console.log('add');
-            console.log(v1);
-            console.log(v2);
+            var v1 = bufferSMToInt(this.stackTop(2));
+            var v2 = bufferSMToInt(this.stackTop(1));
             var num;
             switch (opcode) {
               case OP_ADD:
@@ -559,7 +555,7 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
             }
             this.stackPop();
             this.stackPop();
-            this.stack.push(bigintToBuffer(num));
+            this.stack.push(intToBufferSM(num));
 
             if (opcode === OP_NUMEQUALVERIFY) {
               if (castBool(this.stackTop())) {
@@ -572,14 +568,14 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
 
           case OP_WITHIN:
             // (x min max -- out)
-            var v1 = castBigint(this.stackTop(3));
-            var v2 = castBigint(this.stackTop(2));
-            var v3 = castBigint(this.stackTop(1));
+            var v1 = bufferSMToInt(this.stackTop(3));
+            var v2 = bufferSMToInt(this.stackTop(2));
+            var v3 = bufferSMToInt(this.stackTop(1));
             this.stackPop();
             this.stackPop();
             this.stackPop();
             var value = v1.cmp(v2) >= 0 && v1.cmp(v3) < 0;
-            this.stack.push(bigintToBuffer(value ? 1 : 0));
+            this.stack.push(intToBufferSM(value ? 1 : 0));
             break;
 
           case OP_RIPEMD160:
@@ -759,7 +755,6 @@ ScriptInterpreter.prototype.eval = function eval(script, tx, inIndex, hashType,
             return;
 
           default:
-            console.log('opcode '+opcode);
             throw new Error("Unknown opcode encountered");
         }
 
@@ -854,7 +849,7 @@ ScriptInterpreter.prototype.getPrimitiveStack = function getPrimitiveStack() {
     if (entry.length > 2) {
       return buffertools.toHex(entry.slice(0));
     }
-    var num = castBigint(entry);
+    var num = bufferSMToInt(entry);
     if (num.cmp(-128) >= 0 && num.cmp(127) <= 0) {
       return num.toNumber();
     } else {
@@ -876,69 +871,7 @@ var castBool = ScriptInterpreter.castBool = function castBool(v) {
   return false;
 };
 var castInt = ScriptInterpreter.castInt = function castInt(v) {
-  return castBigint(v).toNumber();
-};
-var castBigint = ScriptInterpreter.castBigint = function castBigint(v) {
-  if (!v.length) {
-    return bignum(0);
-  }
-  // Arithmetic operands must be in range [-2^31...2^31]
-  if (v.length > 4) {
-    throw new Error("Bigint cast overflow (> 4 bytes)");
-  }
-
-  var w = new Buffer(v.length);
-  v.copy(w);
-  w = buffertools.reverse(w);
-  console.log('v ='+buffertools.toHex(w));
-  var isNeg = w[0] & 0x80;
-  if (isNeg) {
-    for (var i = 0; i<w.length; i++) {
-      console.log('before = '+w[i]);
-      w[i] = ~w[i];
-      console.log('after  = '+w[i]);
-    }
-    console.log('w ='+buffertools.toHex(w));
-    return bignum.fromBuffer(w).add(bignum(1)).neg();
-  } else {
-    return bignum.fromBuffer(w);
-  }
-};
-
-var padSign = function(b) {
-  var c;
-  if (b[0] & 0x80) {
-    c = new Buffer(b.length + 1);
-    b.copy(c, 1);
-    c[0] = 0;
-  } else {
-    c = b;
-  }
-  return c;
-}
-
-var bigintToBuffer = ScriptInterpreter.bigintToBuffer = function bigintToBuffer(v) {
-  if ("number" === typeof v) {
-    v = bignum(v);
-  }
-  var b, c;
-  var cmp = v.cmp(0);
-  if (cmp > 0) {
-    console.log('positive');
-    b = v.toBuffer();
-    c = padSign(b);
-    c = buffertools.reverse(c);
-  } else if (cmp == 0) {
-    c = new Buffer([]);
-  } else {
-    console.log('negative '+v);
-    b = v.neg().toBuffer();
-    console.log(b);
-    c = padSign(b);
-    c = Util.negativeBuffer(c);
-    c = buffertools.reverse(c);
-  }
-  return c;
+  return bufferSMToInt(v).toNumber();
 };
 
 ScriptInterpreter.prototype.getResult = function getResult() {
diff --git a/test/test.ScriptInterpreter.js b/test/test.ScriptInterpreter.js
index 9dfd47e..dbdbae6 100644
--- a/test/test.ScriptInterpreter.js
+++ b/test/test.ScriptInterpreter.js
@@ -23,28 +23,12 @@ describe('ScriptInterpreter', function() {
     var si = new ScriptInterpreter();
     should.exist(si);
   });
-  var data = [
-    [0, ''],
-    [1, '01'],
-    [-1, 'ff'],
-  ];
-  data.forEach(function(datum) {
-    var i = datum[0];
-    var hex = datum[1];
-    it('bigintToBuffer should work for ' + i, function() {
-      var result = ScriptInterpreter.bigintToBuffer(i);
-      buffertools.toHex(result).should.equal(hex);
-    });
-  });
-  var i = 0;
   testdata.dataScriptValid.forEach(function(datum) {
     if (datum.length < 2) throw new Error('Invalid test data');
     var scriptSig = datum[0]; // script inputs
     var scriptPubKey = datum[1]; // output script
     var human = scriptSig + ' ' + scriptPubKey;
     it('should validate script ' + human, function(done) {
-      i++;
-      console.log(i + ' ' + human);
       ScriptInterpreter.verify(Script.fromHumanReadable(scriptSig),
         Script.fromHumanReadable(scriptPubKey),
         null, 0, 0, // tx, output index, and hashtype
@@ -56,8 +40,6 @@ describe('ScriptInterpreter', function() {
       );
     });
   });
-
-  var i = 0;
   testdata.dataSigCanonical.forEach(function(datum) {
     it('should validate valid canonical signatures', function() {
       ScriptInterpreter.isCanonicalSignature(new Buffer(datum,'hex')).should.equal(true);
@@ -65,7 +47,6 @@ describe('ScriptInterpreter', function() {
   });
    testdata.dataSigNonCanonical.forEach(function(datum) {
     it('should NOT validate invalid canonical signatures', function() {
-
       var sig;
       var isHex;
       //is Hex?
diff --git a/test/test.examples.js b/test/test.examples.js
index 55c9ccd..4115bc7 100644
--- a/test/test.examples.js
+++ b/test/test.examples.js
@@ -15,8 +15,8 @@ var examples = [
 ];
 
 describe('Examples', function() {
-  //before(mute);
-  //after(unmute);
+  before(mute);
+  after(unmute);
   examples.forEach(function(example) {
     it('valid '+example, function() {
       var ex = require('../examples/'+example);
diff --git a/test/test.util.js b/test/test.util.js
index 6edda6e..45deab6 100644
--- a/test/test.util.js
+++ b/test/test.util.js
@@ -39,12 +39,12 @@ describe('util', function() {
   describe('#ripe160', function() {
     var pk = 'a5c756101065ac5b8f689139e6d856fa99e54b5000b6428b43729d334cc9277d';
     it('should work for ' + pk, function() {
-      var pubKeyHash = coinUtil.ripe160(new Buffer(pk,'hex'));
+      var pubKeyHash = coinUtil.ripe160(new Buffer(pk, 'hex'));
       var pkh = buffertools.toHex(pubKeyHash);
       pkh.should.equal('d166a41f27fd4b158f70314e5eee8998bf3d97d5');
     });
   });
- 
+
 
   describe('#sha256', function() {
     var pk = '03d95e184cce34c3cfa58e9a277a09a7c5ed1b2a8134ea1e52887bc66fa3f47071'
@@ -54,7 +54,7 @@ describe('util', function() {
       pkh.should.equal('a5c756101065ac5b8f689139e6d856fa99e54b5000b6428b43729d334cc9277d');
     });
   });
- 
+
   describe('#sha256ripe160', function() {
     var pk = '03d95e184cce34c3cfa58e9a277a09a7c5ed1b2a8134ea1e52887bc66fa3f47071'
     it('should work for ' + pk, function() {
@@ -71,7 +71,7 @@ describe('util', function() {
     ];
     ripemdData.forEach(function(datum) {
       it('should work for ' + datum[0], function() {
-        var r = coinUtil.ripe160( new bitcore.Buffer(datum[0]));
+        var r = coinUtil.ripe160(new bitcore.Buffer(datum[0]));
         buffertools.toHex(r).should.equal(datum[1]);
       });
       it('should work for Buffer ' + datum[0], function() {
@@ -80,7 +80,7 @@ describe('util', function() {
       });
     });
   });
-  describe('#intToBuffer', function() {
+  describe('#intToBuffer2C', function() {
     var data = [
       [0, ''],
       [-0, ''],
@@ -109,13 +109,13 @@ describe('util', function() {
       var integer = datum[0];
       var result = datum[1];
       it('should work for ' + integer, function() {
-        buffertools.toHex(coinUtil.intToBuffer(integer)).should.equal(result);
+        buffertools.toHex(coinUtil.intToBuffer2C(integer)).should.equal(result);
       });
     });
   });
   describe('#varIntBuf', function() {
     var data = [
-      [0, '00' ],
+      [0, '00'],
       [1, '01'],
       [253, 'fdfd00'],
       [254, 'fdfe00'],
@@ -161,4 +161,22 @@ describe('util', function() {
       });
     });
   });
+  describe('#intToBufferSM', function() {
+    var data = [
+      [0, ''],
+      [1, '01'],
+      [-1, '81'],
+      [2, '02'],
+      [-2, '82'],
+      [-32768, '008080'],
+    ];
+    data.forEach(function(datum) {
+      var i = datum[0];
+      var hex = datum[1];
+      it('should work for ' + i, function() {
+        var result = coinUtil.intToBufferSM(i);
+        buffertools.toHex(result).should.equal(hex);
+      });
+    });
+  });
 });
diff --git a/util/util.js b/util/util.js
index 1732682..75555ce 100644
--- a/util/util.js
+++ b/util/util.js
@@ -133,11 +133,16 @@ exports.negativeBuffer = negativeBuffer = function(b) {
     c[i] += 1;
     if (c[i] !== 0) break;
   }
-  console.log('negative of '+buffertools.toHex(b)+' is '+buffertools.toHex(c));
   return c;
-}
+};
 
-exports.intToBuffer = function(integer) {
+/*
+ * Transforms an integer into a buffer using two-complement encoding
+ * For example, 1 is encoded as 01 and -1 is encoded as ff
+ * For more info see: 
+ * http://en.wikipedia.org/wiki/Signed_number_representations#Two.27s_complement
+ */
+exports.intToBuffer2C = function(integer) {
   var size = bytesNeededToStore(integer);
   var buf = new Put();
   var s = integer.toString(16);
@@ -159,6 +164,73 @@ exports.intToBuffer = function(integer) {
   return ret;
 };
 
+
+var padSign = function(b) {
+  var c;
+  if (b[0] & 0x80) {
+    c = new Buffer(b.length + 1);
+    b.copy(c, 1);
+    c[0] = 0;
+  } else {
+    c = b;
+  }
+  return c;
+}
+
+
+/*
+ * Transforms an integer into a buffer using sign+magnitude encoding
+ * For example, 1 is encoded as 01 and -1 is encoded as 81
+ * For more info see: 
+ * http://en.wikipedia.org/wiki/Signed_number_representations#Signed_magnitude_representation
+ */
+exports.intToBufferSM = function(v) {
+  if ("number" === typeof v) {
+    v = bignum(v);
+  }
+  var b, c;
+  var cmp = v.cmp(0);
+  if (cmp > 0) {
+    b = v.toBuffer();
+    c = padSign(b);
+    c = buffertools.reverse(c);
+  } else if (cmp == 0) {
+    c = new Buffer([]);
+  } else {
+    b = v.neg().toBuffer();
+    c = padSign(b);
+    c[0] |= 0x80;
+    c = buffertools.reverse(c);
+  }
+  return c;
+};
+
+/*
+ * Reverse of intToBufferSM
+ */
+exports.bufferSMToInt = function(v) {
+  if (!v.length) {
+    return bignum(0);
+  }
+  // Arithmetic operands must be in range [-2^31...2^31]
+  if (v.length > 4) {
+    throw new Error('Bigint cast overflow (> 4 bytes)');
+  }
+
+  var w = new Buffer(v.length);
+  v.copy(w);
+  w = buffertools.reverse(w);
+  var isNeg = w[0] & 0x80;
+  if (isNeg) {
+    w[0] &= 0x7f;
+    return bignum.fromBuffer(w).neg();
+  } else {
+    return bignum.fromBuffer(w);
+  }
+};
+
+
+
 var formatValue = exports.formatValue = function (valueBuffer) {
   var value = valueToBigInt(valueBuffer).toString();
   var integerPart = value.length > 8 ? value.substr(0, value.length-8) : '0';