Merge #14816: Add CScriptNum decode python implementation in functional suite

2012d4df2 Add CScriptNum decode python implementation in functional suite (Gregory Sanders)

Pull request description:

  I needed this for reasons and thought it'd be good to upsteam it.

Tree-SHA512: 6ea89fa2a5f5a7759ba722f2b4ed5cd6423ebfff4e83ac8b8b5c935e6aa479684e626c5f41fa020816d2a9079a99af5564e30808594d5c13e3b51ec9b474926d
This commit is contained in:
Wladimir J. van der Laan 2018-12-04 11:28:43 +01:00
commit 0257062e50
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2 changed files with 26 additions and 2 deletions

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@ -25,7 +25,7 @@ from test_framework.util import (
assert_raises_rpc_error,
bytes_to_hex_str as b2x,
)
from test_framework.script import CScriptNum
def assert_template(node, block, expect, rehash=True):
if rehash:
@ -65,11 +65,19 @@ class MiningTest(BitcoinTestFramework):
assert 'proposal' in tmpl['capabilities']
assert 'coinbasetxn' not in tmpl
coinbase_tx = create_coinbase(height=int(tmpl["height"]) + 1)
next_height = int(tmpl["height"])
coinbase_tx = create_coinbase(height=next_height)
# sequence numbers must not be max for nLockTime to have effect
coinbase_tx.vin[0].nSequence = 2 ** 32 - 2
coinbase_tx.rehash()
# round-trip the encoded bip34 block height commitment
assert_equal(CScriptNum.decode(coinbase_tx.vin[0].scriptSig), next_height)
# round-trip negative and multi-byte CScriptNums to catch python regression
assert_equal(CScriptNum.decode(CScriptNum.encode(CScriptNum(1500))), 1500)
assert_equal(CScriptNum.decode(CScriptNum.encode(CScriptNum(-1500))), -1500)
assert_equal(CScriptNum.decode(CScriptNum.encode(CScriptNum(-1))), -1)
block = CBlock()
block.nVersion = tmpl["version"]
block.hashPrevBlock = int(tmpl["previousblockhash"], 16)

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@ -385,6 +385,22 @@ class CScriptNum:
r[-1] |= 0x80
return bytes([len(r)]) + r
@staticmethod
def decode(vch):
result = 0
# We assume valid push_size and minimal encoding
value = vch[1:]
if len(value) == 0:
return result
for i, byte in enumerate(value):
result |= int(byte) << 8*i
if value[-1] >= 0x80:
# Mask for all but the highest result bit
num_mask = (2**(len(value)*8) - 1) >> 1
result &= num_mask
result *= -1
return result
class CScript(bytes):
"""Serialized script