mirror of
https://github.com/bitcoinbook/bitcoinbook
synced 2024-11-22 08:08:11 +00:00
69 lines
2.5 KiB
Python
69 lines
2.5 KiB
Python
# Selects outputs from a UTXO list using a greedy algorithm.
|
|
|
|
from sys import argv
|
|
|
|
class OutputInfo:
|
|
|
|
def __init__(self, tx_hash, tx_index, value):
|
|
self.tx_hash = tx_hash
|
|
self.tx_index = tx_index
|
|
self.value = value
|
|
|
|
def __repr__(self):
|
|
return "<%s:%s with %s Satoshis>" % (self.tx_hash, self.tx_index,
|
|
self.value)
|
|
|
|
# Select optimal outputs for a send from unspent outputs list.
|
|
# Returns output list and remaining change to be sent to
|
|
# a change address.
|
|
def select_outputs_greedy(unspent, min_value):
|
|
# Fail if empty.
|
|
if not unspent:
|
|
return None
|
|
# Partition into 2 lists.
|
|
lessers = [utxo for utxo in unspent if utxo.value < min_value]
|
|
greaters = [utxo for utxo in unspent if utxo.value >= min_value]
|
|
key_func = lambda utxo: utxo.value
|
|
if greaters:
|
|
# Not-empty. Find the smallest greater.
|
|
min_greater = min(greaters, key=key_func)
|
|
change = min_greater.value - min_value
|
|
return [min_greater], "Change: %d Satoshis" % change
|
|
# Not found in greaters. Try several lessers instead.
|
|
# Rearrange them from biggest to smallest. We want to use the least
|
|
# amount of inputs as possible.
|
|
lessers.sort(key=key_func, reverse=True)
|
|
result = []
|
|
accum = 0
|
|
for utxo in lessers:
|
|
result.append(utxo)
|
|
accum += utxo.value
|
|
if accum >= min_value:
|
|
change = accum - min_value
|
|
return result, "Change: %d Satoshis" % change
|
|
# No results found.
|
|
return None, 0
|
|
|
|
def main():
|
|
unspent = [
|
|
OutputInfo("ebadfaa92f1fd29e2fe296eda702c48bd11ffd52313e986e99ddad9084062167", 1, 8000000),
|
|
OutputInfo("6596fd070679de96e405d52b51b8e1d644029108ec4cbfe451454486796a1ecf", 0, 16050000),
|
|
OutputInfo("b2affea89ff82557c60d635a2a3137b8f88f12ecec85082f7d0a1f82ee203ac4", 0, 10000000),
|
|
OutputInfo("7dbc497969c7475e45d952c4a872e213fb15d45e5cd3473c386a71a1b0c136a1", 0, 25000000),
|
|
OutputInfo("55ea01bd7e9afd3d3ab9790199e777d62a0709cf0725e80a7350fdb22d7b8ec6", 17, 5470541),
|
|
OutputInfo("12b6a7934c1df821945ee9ee3b3326d07ca7a65fd6416ea44ce8c3db0c078c64", 0, 10000000),
|
|
OutputInfo("7f42eda67921ee92eae5f79bd37c68c9cb859b899ce70dba68c48338857b7818", 0, 16100000),
|
|
]
|
|
|
|
if len(argv) > 1:
|
|
target = long(argv[1])
|
|
else:
|
|
target = 55000000
|
|
|
|
print "For transaction amount %d Satoshis (%f bitcoin) use: " % (target, target/10.0**8)
|
|
print select_outputs_greedy(unspent, target)
|
|
|
|
if __name__ == "__main__":
|
|
main()
|
|
|