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annotate src/puppy/helpers.py @ 6:5f6d1a28051a

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add python package config files
author Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
date Sun, 24 Oct 2021 15:18:54 +0200
parents src/helpers.py@1a8d94b500d8
children
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1 import hashlib
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2
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3
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4 def __get_hash(buffer, bytes_order='backward'):
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5 """
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6 Compute hash from bytes
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7 More info about bytes order: https://en.wikipedia.org/wiki/Endianness
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8 :param buffer: bytes, required
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9 :param bytes_order: string, 'backward' or 'forward', optional
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10 :return: string
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11 """
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12
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13 h = hashlib.sha256(buffer).digest()
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14 h = hashlib.sha256(h).digest()
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15
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16 if bytes_order == 'backward':
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17 h = h[::-1]
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18
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19 return h.hex()
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20
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21
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22 def __get_variable_int(f):
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23 """
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24 Get variable int from transaction data
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25 More info: https://learnmeabitcoin.com/technical/varint
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26 :param f: buffer, required
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27 :return: int
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28 """
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29
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30 first_byte = f.read(1)
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31
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32 if first_byte == b'\xfd':
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33 variable_int_bytes = f.read(2)[::-1]
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34 elif first_byte == b'\xfe':
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35 variable_int_bytes = f.read(4)[::-1]
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36 elif first_byte == b'\xff':
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37 variable_int_bytes = f.read(8)[::-1]
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38 else:
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39 variable_int_bytes = first_byte
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40
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41 return int.from_bytes(variable_int_bytes, 'little')