add script asm.

lib/bcoin/script.js

@@ -68,6 +68,16 @@ Witness.prototype.inspect = function inspect() {
   return Witness.format(this.items);
 };
 
+/**
+ * Format the witness object as bitcoind asm.
+ * @param {Boolean?} decode - Attempt to decode hash types.
+ * @returns {String} Human-readable script.
+ */
+
+Witness.prototype.toASM = function toASM(decode) {
+  return Script.formatASM(this.items, decode);
+};
+
 /**
  * Clone the witness object. Note that the raw
  * encoded witness data will be lost. This is
@@ -357,6 +367,16 @@ Stack.prototype.inspect = function inspect() {
   return Witness.format(this.items);
 };
 
+/**
+ * Format the stack as bitcoind asm.
+ * @param {Boolean?} decode - Attempt to decode hash types.
+ * @returns {String} Human-readable script.
+ */
+
+Stack.prototype.toASM = function toASM(decode) {
+  return Script.formatASM(this.items, decode);
+};
+
 Stack.prototype.__defineGetter__('length', function() {
   return this.items.length;
 });
@@ -884,6 +904,16 @@ Script.prototype.inspect = function inspect() {
   return Script.format(this.code);
 };
 
+/**
+ * Format the script as bitcoind asm.
+ * @param {Boolean?} decode - Attempt to decode hash types.
+ * @returns {String} Human-readable script.
+ */
+
+Script.prototype.toASM = function toASM(decode) {
+  return Script.formatASM(this.code, decode);
+};
+
 /**
  * Encode the script to a Buffer. Note that this
  * will _not_ contain the varint size before it.
@@ -2768,6 +2798,15 @@ Script.prototype.isWitnessScripthash = function isWitnessScripthash() {
   return this.code[0] === opcodes.OP_0 && this.code[1].length === 32;
 };
 
+/**
+ * Test whether the output script is unspendable.
+ * @returns {Boolean}
+ */
+
+Script.prototype.isUnspendable = function isUnspendable() {
+  return this.code.length > 0 && this.code[0] === opcodes.OP_RETURN;
+};
+
 /**
  * "Guess" the type of the input script.
  * This method is not 100% reliable.
@@ -3433,6 +3472,60 @@ Script.format = function format(code) {
   }).join(' ');
 };
 
+/**
+ * Format script code into bitcoind asm format.
+ * @param {Array} code
+ * @param {Boolean?} decode - Attempt to decode hash types.
+ * @returns {String} Human-readable string.
+ */
+
+Script.formatASM = function formatASM(code, decode) {
+  var out = [];
+  var i, op, type, symbol;
+
+  for (i = 0; i < code.length; i++) {
+    op = code[i];
+
+    if (Script.isBadPush(op)) {
+      out.push('[error]');
+      break;
+    }
+
+    if (Buffer.isBuffer(op)) {
+      if (op.length <= 4) {
+        op = Script.num(op, constants.flags.VERIFY_NONE);
+        out.push(op.toNumber());
+        continue;
+      }
+
+      if (decode && code[0] !== opcodes.OP_RETURN) {
+        symbol = '';
+        if (Script.isSignatureEncoding(op)) {
+          type = op[op.length - 1];
+          symbol = constants.hashTypeByVal[type & 0x1f] || '';
+          if (symbol) {
+            if (type & constants.hashType.ANYONECANPAY)
+              symbol += '|ANYONECANPAY';
+            symbol = '[' + symbol + ']';
+          }
+          op = op.slice(0, -1);
+        }
+        out.push(op.toString('hex') + symbol);
+        continue;
+      }
+
+      out.push(op.toString('hex'));
+      continue;
+    }
+
+    op = constants.opcodesByVal[op] || 'OP_UNKNOWN';
+
+    out.push(op);
+  }
+
+  return out.join(' ');
+};
+
 /**
  * Test the script to see if it contains only push ops.
  * Push ops are: OP_1NEGATE, OP_0-OP_16 and all PUSHDATAs.