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mirror of https://github.com/trezor/trezor-firmware.git synced 2024-11-22 15:38:11 +00:00

Added base58 decoder

This commit is contained in:
slush0 2013-12-30 23:34:56 +01:00
parent b4ff6139ae
commit 56eb483f70

55
trezorlib/tools.py Normal file
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__b58chars = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
__b58base = len(__b58chars)
def b58encode(v):
""" encode v, which is a string of bytes, to base58."""
long_value = 0L
for (i, c) in enumerate(v[::-1]):
long_value += (256 ** i) * ord(c)
result = ''
while long_value >= __b58base:
div, mod = divmod(long_value, __b58base)
result = __b58chars[mod] + result
long_value = div
result = __b58chars[long_value] + result
# Bitcoin does a little leading-zero-compression:
# leading 0-bytes in the input become leading-1s
nPad = 0
for c in v:
if c == '\0':
nPad += 1
else:
break
return (__b58chars[0] * nPad) + result
def b58decode(v, length):
""" decode v into a string of len bytes."""
long_value = 0L
for (i, c) in enumerate(v[::-1]):
long_value += __b58chars.find(c) * (__b58base ** i)
result = ''
while long_value >= 256:
div, mod = divmod(long_value, 256)
result = chr(mod) + result
long_value = div
result = chr(long_value) + result
nPad = 0
for c in v:
if c == __b58chars[0]:
nPad += 1
else:
break
result = chr(0) * nPad + result
if length is not None and len(result) != length:
return None
return result