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-rw-r--r--test/functional/test_framework/descriptors.py55
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diff --git a/test/functional/test_framework/descriptors.py b/test/functional/test_framework/descriptors.py
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+#!/usr/bin/env python3
+# Copyright (c) 2019 Pieter Wuille
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Utility functions related to output descriptors"""
+
+INPUT_CHARSET = "0123456789()[],'/*abcdefgh@:$%{}IJKLMNOPQRSTUVWXYZ&+-.;<=>?!^_|~ijklmnopqrstuvwxyzABCDEFGH`#\"\\ "
+CHECKSUM_CHARSET = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
+GENERATOR = [0xf5dee51989, 0xa9fdca3312, 0x1bab10e32d, 0x3706b1677a, 0x644d626ffd]
+
+def descsum_polymod(symbols):
+ """Internal function that computes the descriptor checksum."""
+ chk = 1
+ for value in symbols:
+ top = chk >> 35
+ chk = (chk & 0x7ffffffff) << 5 ^ value
+ for i in range(5):
+ chk ^= GENERATOR[i] if ((top >> i) & 1) else 0
+ return chk
+
+def descsum_expand(s):
+ """Internal function that does the character to symbol expansion"""
+ groups = []
+ symbols = []
+ for c in s:
+ if not c in INPUT_CHARSET:
+ return None
+ v = INPUT_CHARSET.find(c)
+ symbols.append(v & 31)
+ groups.append(v >> 5)
+ if len(groups) == 3:
+ symbols.append(groups[0] * 9 + groups[1] * 3 + groups[2])
+ groups = []
+ if len(groups) == 1:
+ symbols.append(groups[0])
+ elif len(groups) == 2:
+ symbols.append(groups[0] * 3 + groups[1])
+ return symbols
+
+def descsum_create(s):
+ """Add a checksum to a descriptor without"""
+ symbols = descsum_expand(s) + [0, 0, 0, 0, 0, 0, 0, 0]
+ checksum = descsum_polymod(symbols) ^ 1
+ return s + '#' + ''.join(CHECKSUM_CHARSET[(checksum >> (5 * (7 - i))) & 31] for i in range(8))
+
+def descsum_check(s, require=True):
+ """Verify that the checksum is correct in a descriptor"""
+ if not '#' in s:
+ return not require
+ if s[-9] != '#':
+ return False
+ if not all(x in CHECKSUM_CHARSET for x in s[-8:]):
+ return False
+ symbols = descsum_expand(s[:-9]) + [CHECKSUM_CHARSET.find(x) for x in s[-8:]]
+ return descsum_polymod(symbols) == 1