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