e0cfb2179d
turns out stdlib ord() is somewhat slow;
also, only lookup data chars once
benchmarked with:
```
import time
import electrum
from electrum.segwit_addr import bech32_decode
electrum.constants.set_testnet()
inv = "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"
def f():
for _ in range(10000):
addr = bech32_decode(inv, ignore_long_length=True)
t0 = time.time()
f()
t1 = time.time()
print(f"{t1-t0:.4f}")
```
131 lines
4.5 KiB
Python
131 lines
4.5 KiB
Python
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# Copyright (c) 2017 Pieter Wuille
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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"""Reference implementation for Bech32 and segwit addresses."""
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CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
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_CHARSET_INVERSE = {x: CHARSET.find(x) for x in CHARSET}
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def bech32_polymod(values):
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"""Internal function that computes the Bech32 checksum."""
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generator = [0x3b6a57b2, 0x26508e6d, 0x1ea119fa, 0x3d4233dd, 0x2a1462b3]
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chk = 1
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for value in values:
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top = chk >> 25
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chk = (chk & 0x1ffffff) << 5 ^ value
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for i in range(5):
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chk ^= generator[i] if ((top >> i) & 1) else 0
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return chk
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def bech32_hrp_expand(hrp):
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"""Expand the HRP into values for checksum computation."""
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return [ord(x) >> 5 for x in hrp] + [0] + [ord(x) & 31 for x in hrp]
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def bech32_verify_checksum(hrp, data):
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"""Verify a checksum given HRP and converted data characters."""
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return bech32_polymod(bech32_hrp_expand(hrp) + data) == 1
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def bech32_create_checksum(hrp, data):
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"""Compute the checksum values given HRP and data."""
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values = bech32_hrp_expand(hrp) + data
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polymod = bech32_polymod(values + [0, 0, 0, 0, 0, 0]) ^ 1
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return [(polymod >> 5 * (5 - i)) & 31 for i in range(6)]
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def bech32_encode(hrp, data):
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"""Compute a Bech32 string given HRP and data values."""
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combined = data + bech32_create_checksum(hrp, data)
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return hrp + '1' + ''.join([CHARSET[d] for d in combined])
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def bech32_decode(bech: str, ignore_long_length=False):
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"""Validate a Bech32 string, and determine HRP and data."""
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bech_lower = bech.lower()
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if bech_lower != bech and bech.upper() != bech:
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return (None, None)
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pos = bech.rfind('1')
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if pos < 1 or pos + 7 > len(bech) or (not ignore_long_length and len(bech) > 90):
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return (None, None)
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# check that HRP only consists of sane ASCII chars
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if any(ord(x) < 33 or ord(x) > 126 for x in bech[:pos+1]):
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return (None, None)
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bech = bech_lower
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hrp = bech[:pos]
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try:
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data = [_CHARSET_INVERSE[x] for x in bech[pos+1:]]
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except KeyError:
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return (None, None)
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if not bech32_verify_checksum(hrp, data):
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return (None, None)
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return (hrp, data[:-6])
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def convertbits(data, frombits, tobits, pad=True):
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"""General power-of-2 base conversion."""
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acc = 0
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bits = 0
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ret = []
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maxv = (1 << tobits) - 1
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max_acc = (1 << (frombits + tobits - 1)) - 1
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for value in data:
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if value < 0 or (value >> frombits):
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return None
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acc = ((acc << frombits) | value) & max_acc
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bits += frombits
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while bits >= tobits:
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bits -= tobits
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ret.append((acc >> bits) & maxv)
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if pad:
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if bits:
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ret.append((acc << (tobits - bits)) & maxv)
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elif bits >= frombits or ((acc << (tobits - bits)) & maxv):
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return None
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return ret
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def decode(hrp, addr):
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"""Decode a segwit address."""
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if addr is None:
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return (None, None)
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hrpgot, data = bech32_decode(addr)
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if hrpgot != hrp:
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return (None, None)
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decoded = convertbits(data[1:], 5, 8, False)
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if decoded is None or len(decoded) < 2 or len(decoded) > 40:
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return (None, None)
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if data[0] > 16:
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return (None, None)
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if data[0] == 0 and len(decoded) != 20 and len(decoded) != 32:
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return (None, None)
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return (data[0], decoded)
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def encode(hrp, witver, witprog):
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"""Encode a segwit address."""
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ret = bech32_encode(hrp, [witver] + convertbits(witprog, 8, 5))
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assert decode(hrp, ret) != (None, None)
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return ret
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