new method to estimate vSize of unsigned transactions

defichain/transactions/rawtransactions/__init__.py

@@ -11,4 +11,4 @@
 from .witness import WitnessHash, Witness
 
 # Fee
-from .fee import estimate_fee
+from .fee import estimate_size, estimate_fee, estimate_vsize

defichain/transactions/rawtransactions/fee.py

@@ -1,27 +1,56 @@
+import math
+
 from defichain.transactions.constants import TxSize
 from .txinput import TxP2PKHInput, TxP2SHInput, TxP2WPKHInput
 from .tx import Transaction
 
 
-def estimate_fee(tx: Transaction, feePerByte: float):
+def estimate_size(tx: Transaction):
  """
- Signes the transaction to find out the real size
+ Estimates the size of the later signed transaction.
 
- :param tx: (required) the transaction object
+ :param tx: (required) the unsigned transaction object
  :type tx: Transaction
- :param feePerByte: (required) the amount of fee to pay per byte
- :type feePerByte: float
- :return: "int" - the amount of fee to pay
+ :return: "int" - size of the signed transaction
  """
  # Current Size
  size = tx.size()
 
- # Add witniss and signature size
+ # Add witness and signature size
  for input in tx.get_inputs():
  if isinstance(input, TxP2SHInput) or isinstance(input, TxP2WPKHInput):
  size += TxSize.WITNESS_SIGNATURE_LENGTH + TxSize.WITNESS_SIGNATURE + \
  TxSize.PUBLIC_KEY_LENGTH + TxSize.PUBLIC_KEY
  elif isinstance(input, TxP2PKHInput):
  size += TxSize.SCRIPTSIG_SIGNATURE
+ return size
+
+
+def estimate_fee(tx: Transaction, feePerByte: float):
+ """
+ Estimates fees for unsigned transaction
+
+ :param tx: (required) the unsigned transaction object
+ :type tx: Transaction
+ :param feePerByte: (required) the amount of fee to pay per byte
+ :type feePerByte: float
+ :return: "int" - the amount of fee to pay
+ """
+
+ size = estimate_size(tx)
+
  return round(size * feePerByte)
 
+
+def estimate_vsize(tx: Transaction):
+ """
+ Estimates the vSize of the later signed transaction.
+
+ :param tx: (required) the unsigned transaction object
+ :type tx: Transaction
+ :return: "int" - vSize of the signed transaction
+ """
+ unsigned_size = tx.size()
+ signed_size = estimate_size(tx)
+
+ return math.ceil(unsigned_size + (signed_size - unsigned_size) / 4)