text: #!/usr/bin/env python
  #
  # Electrum - lightweight Bitcoin client
  # Copyright (C) 2011 Thomas Voegtlin
  #
  # Permission is hereby granted, free of charge, to any person
  # obtaining a copy of this software and associated documentation files
  # (the "Software"), to deal in the Software without restriction,
  # including without limitation the rights to use, copy, modify, merge,
  # publish, distribute, sublicense, and/or sell copies of the Software,
  # and to permit persons to whom the Software is furnished to do so,
  # subject to the following conditions:
  #
  # The above copyright notice and this permission notice shall be
  # included in all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  # BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  # ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  # CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  # SOFTWARE.
  
  
  
  # Note: The deserialization code originally comes from ABE.
  
  from .util import print_error, profiler
  
  from .bitcoin import *
  from .address import (PublicKey, Address, Script, ScriptOutput, hash160,
                        UnknownAddress, OpCodes as opcodes)
  import struct
  
  #
  # Workalike python implementation of Bitcoin's CDataStream class.
  #
  from .keystore import xpubkey_to_address, xpubkey_to_pubkey
  
  NO_SIGNATURE = 'ff'
  
  
  class SerializationError(Exception):
      """ Thrown when there's a problem deserializing or serializing """
  
  class InputValueMissing(Exception):
      """ thrown when the value of an input is needed but not present """
  
  class BCDataStream(object):
      def __init__(self):
          self.input = None
          self.read_cursor = 0
  
      def clear(self):
          self.input = None
          self.read_cursor = 0
  
      def write(self, _bytes):  # Initialize with string of _bytes
          if self.input is None:
              self.input = bytearray(_bytes)
          else:
              self.input += bytearray(_bytes)
  
      def read_string(self, encoding='ascii'):
          # Strings are encoded depending on length:
          # 0 to 252 :  1-byte-length followed by bytes (if any)
          # 253 to 65,535 : byte'253' 2-byte-length followed by bytes
          # 65,536 to 4,294,967,295 : byte '254' 4-byte-length followed by bytes
          # ... and the Bitcoin client is coded to understand:
          # greater than 4,294,967,295 : byte '255' 8-byte-length followed by bytes of string
          # ... but I don't think it actually handles any strings that big.
          if self.input is None:
              raise SerializationError("call write(bytes) before trying to deserialize")
  
          length = self.read_compact_size()
  
          return self.read_bytes(length).decode(encoding)
  
      def write_string(self, string, encoding='ascii'):
          string = to_bytes(string, encoding)
          # Length-encoded as with read-string
          self.write_compact_size(len(string))
          self.write(string)
  
      def read_bytes(self, length):
          try:
              result = self.input[self.read_cursor:self.read_cursor+length]
              self.read_cursor += length
              return result
          except IndexError:
              raise SerializationError("attempt to read past end of buffer")
  
          return ''
  
      def read_boolean(self): return self.read_bytes(1)[0] != chr(0)
      def read_int16(self): return self._read_num('<h')
      def read_uint16(self): return self._read_num('<H')
      def read_int32(self): return self._read_num('<i')
      def read_uint32(self): return self._read_num('<I')
      def read_int64(self): return self._read_num('<q')
      def read_uint64(self): return self._read_num('<Q')
  
      def write_boolean(self, val): return self.write(chr(1) if val else chr(0))
      def write_int16(self, val): return self._write_num('<h', val)
      def write_uint16(self, val): return self._write_num('<H', val)
      def write_int32(self, val): return self._write_num('<i', val)
      def write_uint32(self, val): return self._write_num('<I', val)
      def write_int64(self, val): return self._write_num('<q', val)
      def write_uint64(self, val): return self._write_num('<Q', val)
  
      def read_compact_size(self):
          try:
              size = self.input[self.read_cursor]
              self.read_cursor += 1
              if size == 253:
                  size = self._read_num('<H')
              elif size == 254:
                  size = self._read_num('<I')
              elif size == 255:
                  size = self._read_num('<Q')
              return size
          except IndexError:
              raise SerializationError("attempt to read past end of buffer")
  
      def write_compact_size(self, size):
          if size < 0:
              raise SerializationError("attempt to write size < 0")
          elif size < 253:
              self.write(bytes([size]))
          elif size < 2**16:
              self.write(b'\xfd')
              self._write_num('<H', size)
          elif size < 2**32:
              self.write(b'\xfe')
              self._write_num('<I', size)
          elif size < 2**64:
              self.write(b'\xff')
              self._write_num('<Q', size)
  
      def _read_num(self, format):
          try:
              (i,) = struct.unpack_from(format, self.input, self.read_cursor)
              self.read_cursor += struct.calcsize(format)
          except Exception as e:
              raise SerializationError(e)
          return i
  
      def _write_num(self, format, num):
          s = struct.pack(format, num)
          self.write(s)
  
  
  # This function comes from bitcointools, bct-LICENSE.txt.
  def long_hex(bytes):
      return bytes.encode('hex_codec')
  
  # This function comes from bitcointools, bct-LICENSE.txt.
  def short_hex(bytes):
      t = bytes.encode('hex_codec')
      if len(t) < 11:
          return t
      return t[0:4]+"..."+t[-4:]
  
  
  def script_GetOp(_bytes):
      i = 0
      blen = len(_bytes)
      while i < blen:
          vch = None
          opcode = _bytes[i]
          i += 1
  
          if opcode <= opcodes.OP_PUSHDATA4:
              nSize = opcode
              if opcode == opcodes.OP_PUSHDATA1:
                  nSize = _bytes[i] if i < blen else 0
                  i += 1
              elif opcode == opcodes.OP_PUSHDATA2:
                  (nSize,) = struct.unpack_from('<H', _bytes, i) if i+2 <= blen else (0,) # tolerate truncated script
                  i += 2
              elif opcode == opcodes.OP_PUSHDATA4:
                  (nSize,) = struct.unpack_from('<I', _bytes, i) if i+4 <= blen else (0,)
                  i += 4
              vch = _bytes[i:i + nSize] # array slicing here never throws exception even if truncated script
              i += nSize
  
          yield opcode, vch, i
  
  
  def script_GetOpName(opcode):
      return (opcodes.whatis(opcode)).replace("OP_", "")
  
  
  def decode_script(bytes):
      result = ''
      for (opcode, vch, i) in script_GetOp(bytes):
          if len(result) > 0: result += " "
          if opcode <= opcodes.OP_PUSHDATA4:
              result += "%d:"%(opcode,)
              result += short_hex(vch)
          else:
              result += script_GetOpName(opcode)
      return result
  
  
  def match_decoded(decoded, to_match):
      if len(decoded) != len(to_match):
          return False;
      for i in range(len(decoded)):
          if to_match[i] == opcodes.OP_PUSHDATA4 and decoded[i][0] <= opcodes.OP_PUSHDATA4 and decoded[i][0]>0:
              continue  # Opcodes below OP_PUSHDATA4 all just push data onto stack, and are equivalent.
          if to_match[i] != decoded[i][0]:
              return False
      return True
  
  
  def parse_sig(x_sig):
      return [None if x == NO_SIGNATURE else x for x in x_sig]
  
  def safe_parse_pubkey(x):
      try:
          return xpubkey_to_pubkey(x)
      except:
          return x
  
  def parse_scriptSig(d, _bytes):
      try:
          decoded = list(script_GetOp(_bytes))
      except Exception as e:
          # coinbase transactions raise an exception
          print_error("cannot find address in input script", bh2u(_bytes))
          return
  
      match = [ opcodes.OP_PUSHDATA4 ]
      if match_decoded(decoded, match):
          item = decoded[0][1]
          # payto_pubkey
          d['type'] = 'p2pk'
          d['signatures'] = [bh2u(item)]
          d['num_sig'] = 1
          d['x_pubkeys'] = ["(pubkey)"]
          d['pubkeys'] = ["(pubkey)"]
          return
  
      # non-generated TxIn transactions push a signature
      # (seventy-something bytes) and then their public key
      # (65 bytes) onto the stack:
      match = [ opcodes.OP_PUSHDATA4, opcodes.OP_PUSHDATA4 ]
      if match_decoded(decoded, match):
          sig = bh2u(decoded[0][1])
          x_pubkey = bh2u(decoded[1][1])
          try:
              signatures = parse_sig([sig])
              pubkey, address = xpubkey_to_address(x_pubkey)
          except:
              print_error("cannot find address in input script", bh2u(_bytes))
              return
          d['type'] = 'p2pkh'
          d['signatures'] = signatures
          d['x_pubkeys'] = [x_pubkey]
          d['num_sig'] = 1
          d['pubkeys'] = [pubkey]
          d['address'] = address
          return
  
      # p2sh transaction, m of n
      match = [ opcodes.OP_0 ] + [ opcodes.OP_PUSHDATA4 ] * (len(decoded) - 1)
      if not match_decoded(decoded, match):
          print_error("cannot find address in input script", bh2u(_bytes))
          return
      x_sig = [bh2u(x[1]) for x in decoded[1:-1]]
      m, n, x_pubkeys, pubkeys, redeemScript = parse_redeemScript(decoded[-1][1])
      # write result in d
      d['type'] = 'p2sh'
      d['num_sig'] = m
      d['signatures'] = parse_sig(x_sig)
      d['x_pubkeys'] = x_pubkeys
      d['pubkeys'] = pubkeys
      d['redeemScript'] = redeemScript
      d['address'] = Address.from_P2SH_hash(hash160(redeemScript))
  
  
  def parse_redeemScript(s):
      dec2 = [ x for x in script_GetOp(s) ]
      m = dec2[0][0] - opcodes.OP_1 + 1
      n = dec2[-2][0] - opcodes.OP_1 + 1
      op_m = opcodes.OP_1 + m - 1
      op_n = opcodes.OP_1 + n - 1
      match_multisig = [ op_m ] + [opcodes.OP_PUSHDATA4]*n + [ op_n, opcodes.OP_CHECKMULTISIG ]
      if not match_decoded(dec2, match_multisig):
          print_error("cannot find address in input script", bh2u(s))
          return
      x_pubkeys = [bh2u(x[1]) for x in dec2[1:-2]]
      pubkeys = [safe_parse_pubkey(x) for x in x_pubkeys]
      redeemScript = Script.multisig_script(m, [bytes.fromhex(p)
                                                for p in pubkeys])
      return m, n, x_pubkeys, pubkeys, redeemScript
  
  def get_address_from_output_script(_bytes):
      decoded = [x for x in script_GetOp(_bytes)]
  
      # The Genesis Block, self-payments, and pay-by-IP-address payments look like:
      # 65 BYTES:... CHECKSIG
      match = [ opcodes.OP_PUSHDATA4, opcodes.OP_CHECKSIG ]
      if match_decoded(decoded, match):
          return TYPE_PUBKEY, PublicKey.from_pubkey(decoded[0][1])
  
      # Pay-by-Bitcoin-address TxOuts look like:
      # DUP HASH160 20 BYTES:... EQUALVERIFY CHECKSIG
      match = [ opcodes.OP_DUP, opcodes.OP_HASH160, opcodes.OP_PUSHDATA4, opcodes.OP_EQUALVERIFY, opcodes.OP_CHECKSIG ]
      if match_decoded(decoded, match):
          return TYPE_ADDRESS, Address.from_P2PKH_hash(decoded[2][1])
  
      # p2sh
      match = [ opcodes.OP_HASH160, opcodes.OP_PUSHDATA4, opcodes.OP_EQUAL ]
      if match_decoded(decoded, match):
          return TYPE_ADDRESS, Address.from_P2SH_hash(decoded[1][1])
  
      return TYPE_SCRIPT, ScriptOutput(bytes(_bytes))
  
  
  def parse_input(vds):
      d = {}
      prevout_hash = hash_encode(vds.read_bytes(32))
      prevout_n = vds.read_uint32()
      scriptSig = vds.read_bytes(vds.read_compact_size())
      sequence = vds.read_uint32()
      d['prevout_hash'] = prevout_hash
      d['prevout_n'] = prevout_n
      d['sequence'] = sequence
      d['address'] = UnknownAddress()
      if prevout_hash == '00'*32:
          d['type'] = 'coinbase'
          d['scriptSig'] = bh2u(scriptSig)
      else:
          d['x_pubkeys'] = []
          d['pubkeys'] = []
          d['signatures'] = {}
          d['address'] = None
          d['type'] = 'unknown'
          d['num_sig'] = 0
          d['scriptSig'] = bh2u(scriptSig)
          parse_scriptSig(d, scriptSig)
  
          if not Transaction.is_txin_complete(d):
              d['value'] = vds.read_uint64()
      return d
  
  
  def parse_output(vds, i):
      d = {}
      d['value'] = vds.read_int64()
      scriptPubKey = vds.read_bytes(vds.read_compact_size())
      d['type'], d['address'] = get_address_from_output_script(scriptPubKey)
      d['scriptPubKey'] = bh2u(scriptPubKey)
      d['prevout_n'] = i
      return d
  
  
  def deserialize(raw):
      vds = BCDataStream()
      vds.write(bfh(raw))
      d = {}
      start = vds.read_cursor
      d['version'] = vds.read_int32()
      n_vin = vds.read_compact_size()
      assert n_vin != 0
      d['inputs'] = [parse_input(vds) for i in range(n_vin)]
      n_vout = vds.read_compact_size()
      d['outputs'] = [parse_output(vds, i) for i in range(n_vout)]
      d['lockTime'] = vds.read_uint32()
      return d
  
  
  # pay & redeem scripts
  
  
  
  def multisig_script(public_keys, m):
      n = len(public_keys)
      assert n <= 15
      assert m <= n
      op_m = format(opcodes.OP_1 + m - 1, 'x')
      op_n = format(opcodes.OP_1 + n - 1, 'x')
      keylist = [op_push(len(k)//2) + k for k in public_keys]
      return op_m + ''.join(keylist) + op_n + 'ae'
  
  
  
  
  class Transaction:
  
      SIGHASH_FORKID = 0x40
      FORKID = 0x000000
  
      def __str__(self):
          if self.raw is None:
              self.raw = self.serialize()
          return self.raw
  
      def __init__(self, raw):
          if raw is None:
              self.raw = None
          elif isinstance(raw, str):
              self.raw = raw.strip() if raw else None
          elif isinstance(raw, dict):
              self.raw = raw['hex']
          else:
              raise BaseException("cannot initialize transaction", raw)
          self._inputs = None
          self._outputs = None
          self.locktime = 0
          self.version = 1
          
          # Ephemeral meta-data used internally to keep track of interesting things.
          # This is currently written-to by coinchooser to tell UI code about 'dust_to_fee', which
          # is change that's too small to go to change outputs (below dust threshold) and needed
          # to go to the fee. Values in this dict are advisory only and may or may not always be there!
          self.ephemeral = dict()
  
      def update(self, raw):
          self.raw = raw
          self._inputs = None
          self.deserialize()
  
      def inputs(self):
          if self._inputs is None:
              self.deserialize()
          return self._inputs
  
      def outputs(self):
          if self._outputs is None:
              self.deserialize()
          return self._outputs
  
      @classmethod
      def get_sorted_pubkeys(self, txin):
          # sort pubkeys and x_pubkeys, using the order of pubkeys
          x_pubkeys = txin['x_pubkeys']
          pubkeys = txin.get('pubkeys')
          if pubkeys is None:
              pubkeys = [xpubkey_to_pubkey(x) for x in x_pubkeys]
              pubkeys, x_pubkeys = zip(*sorted(zip(pubkeys, x_pubkeys)))
              txin['pubkeys'] = pubkeys = list(pubkeys)
              txin['x_pubkeys'] = x_pubkeys = list(x_pubkeys)
          return pubkeys, x_pubkeys
  
      def update_signatures(self, raw):
          """Add new signatures to a transaction"""
          d = deserialize(raw)
          for i, txin in enumerate(self.inputs()):
              pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
              sigs1 = txin.get('signatures')
              sigs2 = d['inputs'][i].get('signatures')
              for sig in sigs2:
                  if sig in sigs1:
                      continue
                  pre_hash = Hash(bfh(self.serialize_preimage(i)))
                  # der to string
                  order = ecdsa.ecdsa.generator_secp256k1.order()
                  r, s = ecdsa.util.sigdecode_der(bfh(sig[:-2]), order)
                  sig_string = ecdsa.util.sigencode_string(r, s, order)
                  compressed = True
                  for recid in range(4):
                      public_key = MyVerifyingKey.from_signature(sig_string, recid, pre_hash, curve = SECP256k1)
                      pubkey = bh2u(point_to_ser(public_key.pubkey.point, compressed))
                      if pubkey in pubkeys:
                          public_key.verify_digest(sig_string, pre_hash, sigdecode = ecdsa.util.sigdecode_string)
                          j = pubkeys.index(pubkey)
                          print_error("adding sig", i, j, pubkey, sig)
                          self._inputs[i]['signatures'][j] = sig
                          break
          # redo raw
          self.raw = self.serialize()
  
      def deserialize(self):
          if self.raw is None:
              return
          if self._inputs is not None:
              return
          d = deserialize(self.raw)
          self._inputs = d['inputs']
          self._outputs = [(x['type'], x['address'], x['value']) for x in d['outputs']]
          assert all(isinstance(output[1], (PublicKey, Address, ScriptOutput))
                     for output in self._outputs)
          self.locktime = d['lockTime']
          self.version = d['version']
          return d
  
      @classmethod
      def from_io(klass, inputs, outputs, locktime=0):
          assert all(isinstance(output[1], (PublicKey, Address, ScriptOutput))
                     for output in outputs)
          self = klass(None)
          self._inputs = inputs
          self._outputs = outputs.copy()
          self.locktime = locktime
          return self
  
      @classmethod
      def pay_script(self, output):
          return output.to_script().hex()
  
      @classmethod
      def estimate_pubkey_size_from_x_pubkey(cls, x_pubkey):
          try:
              if x_pubkey[0:2] in ['02', '03']:  # compressed pubkey
                  return 0x21
              elif x_pubkey[0:2] == '04':  # uncompressed pubkey
                  return 0x41
              elif x_pubkey[0:2] == 'ff':  # bip32 extended pubkey
                  return 0x21
              elif x_pubkey[0:2] == 'fe':  # old electrum extended pubkey
                  return 0x41
          except Exception as e:
              pass
          return 0x21  # just guess it is compressed
  
      @classmethod
      def estimate_pubkey_size_for_txin(cls, txin):
          pubkeys = txin.get('pubkeys', [])
          x_pubkeys = txin.get('x_pubkeys', [])
          if pubkeys and len(pubkeys) > 0:
              return cls.estimate_pubkey_size_from_x_pubkey(pubkeys[0])
          elif x_pubkeys and len(x_pubkeys) > 0:
              return cls.estimate_pubkey_size_from_x_pubkey(x_pubkeys[0])
          else:
              return 0x21  # just guess it is compressed
  
      @classmethod
      def get_siglist(self, txin, estimate_size=False):
          # if we have enough signatures, we use the actual pubkeys
          # otherwise, use extended pubkeys (with bip32 derivation)
          num_sig = txin.get('num_sig', 1)
          if estimate_size:
              pubkey_size = self.estimate_pubkey_size_for_txin(txin)
              pk_list = ["00" * pubkey_size] * len(txin.get('x_pubkeys', [None]))
              # we assume that signature will be 0x48 bytes long
              sig_list = [ "00" * 0x48 ] * num_sig
          else:
              pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
              x_signatures = txin['signatures']
              signatures = list(filter(None, x_signatures))
              is_complete = len(signatures) == num_sig
              if is_complete:
                  pk_list = pubkeys
                  sig_list = signatures
              else:
                  pk_list = x_pubkeys
                  sig_list = [sig if sig else NO_SIGNATURE for sig in x_signatures]
          return pk_list, sig_list
  
      @classmethod
      def input_script(self, txin, estimate_size=False):
          _type = txin['type']
          if _type == 'coinbase':
              return txin['scriptSig']
          pubkeys, sig_list = self.get_siglist(txin, estimate_size)
          script = ''.join(push_script(x) for x in sig_list)
          if _type == 'p2pk':
              pass
          elif _type == 'p2sh':
              # put op_0 before script
              script = '00' + script
              redeem_script = multisig_script(pubkeys, txin['num_sig'])
              script += push_script(redeem_script)
          elif _type == 'p2pkh':
              script += push_script(pubkeys[0])
          elif _type == 'unknown':
              return txin['scriptSig']
          return script
  
      @classmethod
      def is_txin_complete(self, txin):
          num_sig = txin.get('num_sig', 1)
          x_signatures = txin['signatures']
          signatures = list(filter(None, x_signatures))
          return len(signatures) == num_sig
  
      @classmethod
      def get_preimage_script(self, txin):
          _type = txin['type']
          if _type == 'p2pkh':
              return txin['address'].to_script().hex()
          elif _type == 'p2sh':
              pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
              return multisig_script(pubkeys, txin['num_sig'])
          elif _type == 'p2pk':
              pubkey = txin['pubkeys'][0]
              return public_key_to_p2pk_script(pubkey)
          elif _type == 'unknown':
              # this approach enables most P2SH smart contracts (but take care if using OP_CODESEPARATOR)
              return txin['scriptCode']
          else:
              raise RuntimeError('Unknown txin type', _type)
  
      @classmethod
      def serialize_outpoint(self, txin):
          return bh2u(bfh(txin['prevout_hash'])[::-1]) + int_to_hex(txin['prevout_n'], 4)
  
      @classmethod
      def serialize_input(self, txin, script, estimate_size=False):
          # Prev hash and index
          s = self.serialize_outpoint(txin)
          # Script length, script, sequence
          s += var_int(len(script)//2)
          s += script
          s += int_to_hex(txin.get('sequence', 0xffffffff - 1), 4)
          # offline signing needs to know the input value
          if ('value' in txin   # Legacy txs
              and not (estimate_size or self.is_txin_complete(txin))):
              s += int_to_hex(txin['value'], 8)
          return s
  
      def BIP_LI01_sort(self):
          # See https://github.com/kristovatlas/rfc/blob/master/bips/bip-li01.mediawiki
          self._inputs.sort(key = lambda i: (i['prevout_hash'], i['prevout_n']))
          self._outputs.sort(key = lambda o: (o[2], self.pay_script(o[1])))
  
      def serialize_output(self, output):
          output_type, addr, amount = output
          s = int_to_hex(amount, 8)
          script = self.pay_script(addr)
          s += var_int(len(script)//2)
          s += script
          return s
  
      @classmethod
      def nHashType(cls):
          '''Hash type in hex.'''
          return 0x01 | (cls.SIGHASH_FORKID + (cls.FORKID << 8))
  
      def serialize_preimage(self, i):
          nVersion = int_to_hex(self.version, 4)
          nHashType = int_to_hex(self.nHashType(), 4)
          nLocktime = int_to_hex(self.locktime, 4)
          inputs = self.inputs()
          outputs = self.outputs()
          txin = inputs[i]
  
          hashPrevouts = bh2u(Hash(bfh(''.join(self.serialize_outpoint(txin) for txin in inputs))))
          hashSequence = bh2u(Hash(bfh(''.join(int_to_hex(txin.get('sequence', 0xffffffff - 1), 4) for txin in inputs))))
          hashOutputs = bh2u(Hash(bfh(''.join(self.serialize_output(o) for o in outputs))))
          outpoint = self.serialize_outpoint(txin)
          preimage_script = self.get_preimage_script(txin)
          scriptCode = var_int(len(preimage_script) // 2) + preimage_script
          try:
              amount = int_to_hex(txin['value'], 8)
          except KeyError:
              raise InputValueMissing
          nSequence = int_to_hex(txin.get('sequence', 0xffffffff - 1), 4)
          preimage = nVersion + hashPrevouts + hashSequence + outpoint + scriptCode + amount + nSequence + hashOutputs + nLocktime + nHashType
          return preimage
  
      def serialize(self, estimate_size=False):
          nVersion = int_to_hex(self.version, 4)
          nLocktime = int_to_hex(self.locktime, 4)
          inputs = self.inputs()
          outputs = self.outputs()
          txins = var_int(len(inputs)) + ''.join(self.serialize_input(txin, self.input_script(txin, estimate_size), estimate_size) for txin in inputs)
          txouts = var_int(len(outputs)) + ''.join(self.serialize_output(o) for o in outputs)
          return nVersion + txins + txouts + nLocktime
  
      def hash(self):
          print("warning: deprecated tx.hash()")
          return self.txid()
  
      def txid(self):
          if not self.is_complete():
              return None
          ser = self.serialize()
          return bh2u(Hash(bfh(ser))[::-1])
  
      def add_inputs(self, inputs):
          self._inputs.extend(inputs)
          self.raw = None
  
      def add_outputs(self, outputs):
          assert all(isinstance(output[1], (PublicKey, Address, ScriptOutput))
                     for output in outputs)
          self._outputs.extend(outputs)
          self.raw = None
  
      def input_value(self):
          return sum(x['value'] for x in self.inputs())
  
      def output_value(self):
          return sum(val for tp, addr, val in self.outputs())
  
      def get_fee(self):
          return self.input_value() - self.output_value()
  
      @profiler
      def estimated_size(self):
          '''Return an estimated tx size in bytes.'''
          return len(self.serialize(True)) / 2 if not self.is_complete() or self.raw is None else len(self.raw) / 2 # ASCII hex string
  
      @classmethod
      def estimated_input_size(self, txin):
          '''Return an estimated of serialized input size in bytes.'''
          script = self.input_script(txin, True)
          return len(self.serialize_input(txin, script, True)) / 2
  
      def signature_count(self):
          r = 0
          s = 0
          for txin in self.inputs():
              if txin['type'] == 'coinbase':
                  continue
              signatures = list(filter(None, txin.get('signatures',[])))
              s += len(signatures)
              r += txin.get('num_sig',-1)
          return s, r
  
      def is_complete(self):
          s, r = self.signature_count()
          return r == s
  
      def sign(self, keypairs):
          for i, txin in enumerate(self.inputs()):
              num = txin['num_sig']
              pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
              for j, x_pubkey in enumerate(x_pubkeys):
                  signatures = list(filter(None, txin['signatures']))
                  if len(signatures) == num:
                      # txin is complete
                      break
                  if x_pubkey in keypairs.keys():
                      print_error("adding signature for", x_pubkey)
                      sec, compressed = keypairs.get(x_pubkey)
                      pubkey = public_key_from_private_key(sec, compressed)
                      # add signature
                      pre_hash = Hash(bfh(self.serialize_preimage(i)))
                      pkey = regenerate_key(sec)
                      secexp = pkey.secret
                      private_key = MySigningKey.from_secret_exponent(secexp, curve = SECP256k1)
                      public_key = private_key.get_verifying_key()
                      sig = private_key.sign_digest_deterministic(pre_hash, hashfunc=hashlib.sha256, sigencode = ecdsa.util.sigencode_der)
                      assert public_key.verify_digest(sig, pre_hash, sigdecode = ecdsa.util.sigdecode_der)
                      txin['signatures'][j] = bh2u(sig) + int_to_hex(self.nHashType() & 255, 1)
                      txin['pubkeys'][j] = pubkey # needed for fd keys
                      self._inputs[i] = txin
          print_error("is_complete", self.is_complete())
          self.raw = self.serialize()
  
      def get_outputs(self):
          """convert pubkeys to addresses"""
          o = []
          for type, addr, v in self.outputs():
              o.append((addr,v))      # consider using yield (addr, v)
          return o
  
      def get_output_addresses(self):
          return [addr for addr, val in self.get_outputs()]
  
  
      def has_address(self, addr):
          return (addr in self.get_output_addresses()) or (addr in (tx.get("address") for tx in self.inputs()))
  
      def is_final(self):
          return not any([x.get('sequence', 0xffffffff - 1) < 0xffffffff - 1
                          for x in self.inputs()])
  
  
      def as_dict(self):
          if self.raw is None:
              self.raw = self.serialize()
          self.deserialize()
          out = {
              'hex': self.raw,
              'complete': self.is_complete(),
              'final': self.is_final(),
          }
          return out
  
  
  def tx_from_str(txt):
      "json or raw hexadecimal"
      import json
      txt = txt.strip()
      if not txt:
          raise ValueError("empty string")
      try:
          bfh(txt)
          is_hex = True
      except:
          is_hex = False
      if is_hex:
          return txt
      tx_dict = json.loads(str(txt))
      assert "hex" in tx_dict.keys()
      return tx_dict["hex"]
  