refactor. strict isscripthash.

lib/bcoin/script.js

@@ -865,7 +865,7 @@ Script.prototype.interpret = function interpret(stack, flags, tx, index, version
             n2 = Script.num(stack.pop(), flags);
             n1 = Script.num(stack.pop(), flags);
             val = n2.cmp(n1) <= 0 && n1.cmp(n3) < 0;
-            stack.push(val.cmpn(0) !== 0 ? STACK_TRUE : STACK_FALSE);
+            stack.push(val ? STACK_TRUE : STACK_FALSE);
             break;
         }
 
@@ -1124,7 +1124,7 @@ Script.checkSequence = function checkSequence(sequence, tx, i) {
   var txSequence = tx.inputs[i].sequence;
   var locktimeMask, txSequenceMasked, sequenceMasked;
 
-  if ((tx.version >>> 0) < 2)
+  if (tx.version < 2)
     return false;
 
   if (txSequence & constants.sequenceLocktimeDisableFlag)
@@ -1370,6 +1370,13 @@ Script.createWitnessProgram = function createWitnessProgram(version, data) {
   return new Script([version === 0 ? 0 : version + 0x50, data]);
 };
 
+Script.prototype.createCommitment = function createCommitment(hash) {
+  return new Script([
+    opcodes.OP_RETURN,
+    Buffer.concat([new Buffer([0xaa, 0x21, 0xa9, 0xed]), hash])
+  ]);
+};
+
 Script.prototype.getRedeem = function getRedeem() {
   if (!this.redeem)
     this.redeem = Script.getRedeem(this.code);
@@ -1660,6 +1667,21 @@ Script.prototype.isMultisig = function isMultisig(keys) {
 Script.prototype.isScripthash = function isScripthash(hash) {
   var res;
 
+  // Bitcoind requires strict
+  // minimaldata encoding for scripthash.
+  if (this.raw) {
+    if (hash) {
+      if (!Script.isHash(this.code[1]))
+        return false;
+      if (!utils.isEqual(this.code[1], hash))
+        return false;
+    }
+    return this.raw.length === 23
+      && this.raw[0] === opcodes.OP_HASH160
+      && this.raw[1] === 0x14
+      && this.raw[22] === opcodes.OP_EQUAL;
+  }
+
   if (this.code.length !== 3)
     return false;
 
@@ -1700,13 +1722,6 @@ Script.prototype.isCommitment = function isCommitment() {
     && utils.readU32BE(this.code[1], 0) === 0xaa21a9ed;
 };
 
-Script.prototype.createCommitment = function createCommitment(hash) {
-  return new Script([
-    opcodes.OP_RETURN,
-    Buffer.concat([new Buffer([0xaa, 0x21, 0xa9, 0xed]), hash])
-  ]);
-};
-
 Script.prototype.getCommitmentHash = function getCommitmentHash() {
   if (!this.isCommitment())
     return;