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#!/usr/bin/env python3
# Copyright (c) 2015-2016 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Utilities for manipulating blocks and transactions."""
from .mininode import *
from .script import CScript, OP_TRUE, OP_CHECKSIG, OP_RETURN
# Create a block (with regtest difficulty)
def create_block(hashprev, coinbase, nTime=None):
block = CBlock()
if nTime is None:
import time
block.nTime = int(time.time()+600)
else:
block.nTime = nTime
block.hashPrevBlock = hashprev
block.nBits = 0x207fffff # Will break after a difficulty adjustment...
block.vtx.append(coinbase)
block.hashMerkleRoot = block.calc_merkle_root()
block.calc_sha256()
return block
# From BIP141
WITNESS_COMMITMENT_HEADER = b"\xaa\x21\xa9\xed"
# According to BIP141, blocks with witness rules active must commit to the
# hash of all in-block transactions including witness.
def add_witness_commitment(block, nonce=0):
# First calculate the merkle root of the block's
# transactions, with witnesses.
witness_nonce = nonce
witness_root = block.calc_witness_merkle_root()
witness_commitment = uint256_from_str(hash256(ser_uint256(witness_root)+ser_uint256(witness_nonce)))
# witness_nonce should go to coinbase witness.
block.vtx[0].wit.vtxinwit = [CTxInWitness()]
block.vtx[0].wit.vtxinwit[0].scriptWitness.stack = [ser_uint256(witness_nonce)]
# witness commitment is the last OP_RETURN output in coinbase
output_data = WITNESS_COMMITMENT_HEADER + ser_uint256(witness_commitment)
block.vtx[0].vout.append(CTxOut(0, CScript([OP_RETURN, output_data])))
block.vtx[0].rehash()
block.hashMerkleRoot = block.calc_merkle_root()
block.rehash()
def serialize_script_num(value):
r = bytearray(0)
if value == 0:
return r
neg = value < 0
absvalue = -value if neg else value
while (absvalue):
r.append(int(absvalue & 0xff))
absvalue >>= 8
if r[-1] & 0x80:
r.append(0x80 if neg else 0)
elif neg:
r[-1] |= 0x80
return r
# Create a coinbase transaction, assuming no miner fees.
# If pubkey is passed in, the coinbase output will be a P2PK output;
# otherwise an anyone-can-spend output.
def create_coinbase(height, pubkey = None):
coinbase = CTransaction()
coinbase.vin.append(CTxIn(COutPoint(0, 0xffffffff),
ser_string(serialize_script_num(height)), 0xffffffff))
coinbaseoutput = CTxOut()
coinbaseoutput.nValue = 50 * COIN
halvings = int(height/150) # regtest
coinbaseoutput.nValue >>= halvings
if (pubkey != None):
coinbaseoutput.scriptPubKey = CScript([pubkey, OP_CHECKSIG])
else:
coinbaseoutput.scriptPubKey = CScript([OP_TRUE])
coinbase.vout = [ coinbaseoutput ]
coinbase.calc_sha256()
return coinbase
# Create a transaction.
# If the scriptPubKey is not specified, make it anyone-can-spend.
def create_transaction(prevtx, n, sig, value, scriptPubKey=CScript()):
tx = CTransaction()
assert(n < len(prevtx.vout))
tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), sig, 0xffffffff))
tx.vout.append(CTxOut(value, scriptPubKey))
tx.calc_sha256()
return tx
def get_legacy_sigopcount_block(block, fAccurate=True):
count = 0
for tx in block.vtx:
count += get_legacy_sigopcount_tx(tx, fAccurate)
return count
def get_legacy_sigopcount_tx(tx, fAccurate=True):
count = 0
for i in tx.vout:
count += i.scriptPubKey.GetSigOpCount(fAccurate)
for j in tx.vin:
# scriptSig might be of type bytes, so convert to CScript for the moment
count += CScript(j.scriptSig).GetSigOpCount(fAccurate)
return count