lbry-sdk/lbrynet/schema/base.py

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from lbrynet.schema.constants import ADDRESS_CHECKSUM_LENGTH
from lbrynet.schema.hashing import double_sha256
from lbrynet.schema.error import InvalidAddress
alphabet = b'123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
def scrub_input(v):
if isinstance(v, str) and not isinstance(v, bytes):
v = v.encode('ascii')
return v
def b58encode_int(i, default_one=True):
'''Encode an integer using Base58'''
if not i and default_one:
return alphabet[0:1]
string = b""
while i:
i, idx = divmod(i, 58)
string = alphabet[idx:idx+1] + string
return string
def b58encode(v):
'''Encode a string using Base58'''
v = scrub_input(v)
nPad = len(v)
v = v.lstrip(b'\0')
nPad -= len(v)
p, acc = 1, 0
for c in reversed(v):
acc += p * c
p = p << 8
result = b58encode_int(acc, default_one=False)
return alphabet[0:1] * nPad + result
def b58decode_int(v):
'''Decode a Base58 encoded string as an integer'''
v = scrub_input(v)
decimal = 0
for char in v:
decimal = decimal * 58 + alphabet.index(char)
return decimal
def b58decode(v):
'''Decode a Base58 encoded string'''
v = scrub_input(v)
origlen = len(v)
v = v.lstrip(alphabet[0:1])
newlen = len(v)
acc = b58decode_int(v)
result = []
while acc > 0:
acc, mod = divmod(acc, 256)
result.append(mod)
return b'\0' * (origlen - newlen) + bytes(reversed(result))
def validate_b58_checksum(addr_bytes):
addr_without_checksum = addr_bytes[:-ADDRESS_CHECKSUM_LENGTH]
addr_checksum = addr_bytes[-ADDRESS_CHECKSUM_LENGTH:]
if double_sha256(addr_without_checksum)[:ADDRESS_CHECKSUM_LENGTH] != addr_checksum:
raise InvalidAddress("Invalid address checksum")
def b58decode_strip_checksum(v):
addr_bytes = b58decode(v)
validate_b58_checksum(addr_bytes)
return addr_bytes[:-ADDRESS_CHECKSUM_LENGTH]
def b58encode_with_checksum(addr_bytes):
addr_checksum = double_sha256(addr_bytes)[:ADDRESS_CHECKSUM_LENGTH]
return b58encode(addr_bytes + addr_checksum)