# -*- coding: utf-8 -*-
"""
Low-level helpers, type adapters, and encoding utilities shared across modules.
"""
import binascii
import hashlib
import os
string_types = (str)
string_or_bytes_types = (str, bytes)
int_types = (int, float)
# Base switching
code_strings = {
2: '01',
10: '0123456789',
16: '0123456789abcdef',
32: 'abcdefghijklmnopqrstuvwxyz234567',
58: '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz',
256: ''.join([chr(x) for x in range(256)])
}
[docs]
def bin_dbl_sha256(s):
bytes_to_hash = from_string_to_bytes(s)
return hashlib.sha256(hashlib.sha256(bytes_to_hash).digest()).digest()
[docs]
def lpad(msg, symbol, length):
if len(msg) >= length:
return msg
return symbol * (length - len(msg)) + msg
[docs]
def get_code_string(base):
if base in code_strings:
return code_strings[base]
else:
raise ValueError("Invalid base!")
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def changebase(string, frm, to, minlen=0):
if frm == to:
return lpad(string, get_code_string(frm)[0], minlen)
return encode(decode(string, frm), to, minlen)
[docs]
def bin_to_b58check(inp, magicbyte=0):
if magicbyte == 0:
inp = from_int_to_byte(0) + inp
while magicbyte > 0:
inp = from_int_to_byte(magicbyte % 256) + inp
magicbyte //= 256
leadingzbytes = 0
for x in inp:
if x != 0:
break
leadingzbytes += 1
checksum = bin_dbl_sha256(inp)[:4]
return '1' * leadingzbytes + changebase(inp + checksum, 256, 58)
[docs]
def bytes_to_hex_string(b):
if isinstance(b, str):
return b
return ''.join('{:02x}'.format(y) for y in b)
[docs]
def safe_from_hex(s):
return bytes.fromhex(s)
[docs]
def from_int_representation_to_bytes(a):
return bytes(str(a), 'utf-8')
[docs]
def from_int_to_byte(a):
return bytes([a])
[docs]
def from_byte_to_int(a):
return a
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def from_string_to_bytes(a):
return a if isinstance(a, bytes) else bytes(a, 'utf-8')
[docs]
def safe_hexlify(a):
return str(binascii.hexlify(a), 'utf-8')
[docs]
def encode(val, base, minlen=0):
base, minlen = int(base), int(minlen)
code_string = get_code_string(base)
result_bytes = bytes()
while val > 0:
curcode = code_string[val % base]
result_bytes = bytes([ord(curcode)]) + result_bytes
val //= base
pad_size = minlen - len(result_bytes)
padding_element = b'\x00' if base == 256 else b'1' \
if base == 58 else b'0'
if (pad_size > 0):
result_bytes = padding_element * pad_size + result_bytes
result_string = ''.join([chr(y) for y in result_bytes])
result = result_bytes if base == 256 else result_string
return result
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def decode(string, base):
if base == 256 and isinstance(string, str):
string = bytes(bytearray.fromhex(string))
base = int(base)
code_string = get_code_string(base)
result = 0
if base == 256:
def extract(d, cs):
return d
else:
def extract(d, cs):
return cs.find(d if isinstance(d, str) else chr(d))
if base == 16:
string = string.lower()
while len(string) > 0:
result *= base
result += extract(string[0], code_string)
string = string[1:]
return result
[docs]
def random_string(x):
return str(os.urandom(x))