scripts: extract all scripts to encode/decode/check style

src/templates/scripthash/input.js

@@ -0,0 +1,48 @@
+// <scriptSig> {serialized scriptPubKey script}
+
+var bscript = require('../../script')
+var typeforce = require('typeforce')
+
+function check (script, allowIncomplete) {
+  var chunks = bscript.decompile(script)
+  if (chunks.length < 2) return false
+
+  var lastChunk = chunks[chunks.length - 1]
+  if (!Buffer.isBuffer(lastChunk)) return false
+
+  var scriptSigChunks = chunks.slice(0, -1)
+  var redeemScriptChunks = bscript.decompile(lastChunk)
+
+  // is redeemScript a valid script?
+  if (redeemScriptChunks.length === 0) return false
+
+  var inputType = bscript.classifyInput(scriptSigChunks, allowIncomplete)
+  var outputType = bscript.classifyOutput(redeemScriptChunks)
+  return inputType === outputType
+}
+
+function encode (scriptSignature, scriptPubKey) {
+  var scriptSigChunks = bscript.decompile(scriptSignature)
+  var serializedScriptPubKey = bscript.compile(scriptPubKey)
+
+  return bscript.compile([].concat(
+    scriptSigChunks,
+    serializedScriptPubKey
+  ))
+}
+
+function decode (buffer) {
+  var chunks = bscript.decompile(buffer)
+  typeforce(check, chunks)
+
+  return {
+    scriptSignature: chunks.slice(0, -1),
+    scriptPubKey: chunks[chunks.length - 1]
+  }
+}
+
+module.exports = {
+  check: check,
+  decode: decode,
+  encode: encode
+}