Mercurial > public > bitcaviar-plus

annotate src/helpers.py @ 2:5b16e6df6a59

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
get txid hashing transaction data
author Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
date Sun, 17 Oct 2021 11:14:46 +0200
parents 2327b9eda10f
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
0
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
1 def read_bytes(file, number_of_bytes, bytes_order='backward'):
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
2 """
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
3 Read bytes from buffer
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
4 :param file: <class '_io.BufferedReader'>, required
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
5 :param number_of_bytes: int, required
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
6 :param bytes_order: string, 'backward' or 'forward', required
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
7 :return: string
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
8 """
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
9
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
10 # More info about bytes order: https://en.wikipedia.org/wiki/Endianness
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
11
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
12 b = file.read(number_of_bytes)
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
13 if bytes_order == 'backward':
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
14 b = b[::-1]
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
15
2
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
16 return b
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
17
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
18
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
19 def get_variable_int(file):
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
20 """
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
21 Get variable int from transaction data
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
22 More info: https://learnmeabitcoin.com/technical/varint
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
23 :param file: <class '_io.BufferedReader'>, required
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
24 :return: int
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
25 """
0
2327b9eda10f first commit
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents:
diff changeset
26
2
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
27 first_byte = read_bytes(file, 1)
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
28
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
29 if first_byte == b'\xfd':
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
30 variable_int_bytes = read_bytes(file, 2)
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
31 elif first_byte == b'\xfe':
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
32 variable_int_bytes = read_bytes(file, 4)
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
33 elif first_byte == b'\xff':
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
34 variable_int_bytes = read_bytes(file, 8)
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
35 else:
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
36 variable_int_bytes = first_byte
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
37
5b16e6df6a59 get txid hashing transaction data
Dennis Concepcion Martin <dennisconcepcionmartin@gmail.com>
parents: 0
diff changeset
38 return int.from_bytes(variable_int_bytes, 'little')