import decimal
from binascii import hexlify
import string
class Decimal(decimal.Decimal):
def __new__(cls, value):
return super().__new__(cls, str(value))
def chunk_data(data, size):
return (data[i:i + size] for i in range(0, len(data), size))
def int_to_unknown_bytes(num, byteorder='big'):
"""Converts an int to the least number of bytes as possible."""
return num.to_bytes((num.bit_length() + 7) // 8 or 1, byteorder)
def bytes_to_hex(bytestr, upper=False):
hexed = hexlify(bytestr).decode()
return hexed.upper() if upper else hexed
def hex_to_bytes(hexed):
if len(hexed) & 1:
hexed = '0' + hexed
return bytes.fromhex(hexed)
def int_to_hex(num, upper=False):
"""Ensures that there is an even number of characters in the hex string"""
hexed = hex(num)[2:]
if len(hexed) % 2 != 0:
hexed = '0' + hexed
return hexed.upper() if upper else hexed
def hex_to_int(hexed):
return int(hexed, 16)
def flip_hex_byte_order(string):
return bytes_to_hex(hex_to_bytes(string)[::-1])
def int_to_varint(val):
if val < 253:
return val.to_bytes(1, 'little')
elif val <= 65535:
return b'\xfd'+val.to_bytes(2, 'little')
elif val <= 4294967295:
return b'\xfe'+val.to_bytes(4, 'little')
else:
return b'\xff'+val.to_bytes(8, 'little')
def is_valid_hex(s):
"""Can only detect if something definitely is *not* hex (could still return true by
coincidence).
But in this case all asm op codes begin with "OP_" as per https://en.bitcoin.it/wiki/Script.
So all return False. The only exception to this is for OP_PUSHDATA codes 1 - 75."""
return all(c in string.hexdigits for c in s)
def asm_to_list(asm):
"""Takes in Bitcoin Script Assembly code and returns:
- op_codes (with 'OP_' prefixes) as string
- raw hex data as bytes.
"""
asm_list = []
for pushdata in asm.split(' '):
if not is_valid_hex(pushdata):
asm_list.append(pushdata)
else:
asm_list.append(hex_to_bytes(pushdata))
return asm_list
