mirror of
https://github.com/trezor/trezor-firmware.git
synced 2024-12-13 18:08:10 +00:00
39 lines
1009 B
Python
39 lines
1009 B
Python
|
import sys
|
||
|
|
|
||
|
|
from . import consts
|
||
|
|
|
||
|
|
|
||
|
|
def to_int_by_words(array: bytes) -> int:
|
||
|
|
"""
|
||
|
|
Converts array of bytes into an int by reading word size
|
||
|
|
of bytes then converted to int using the system's endianness.
|
||
|
|
"""
|
||
|
|
assert len(array) % consts.WORD_SIZE == 0
|
||
|
|
n = 0
|
||
|
|
for i in range(0, len(array), consts.WORD_SIZE):
|
||
|
|
n = (n << (consts.WORD_SIZE * 8)) + int.from_bytes(
|
||
|
|
array[i : i + consts.WORD_SIZE], sys.byteorder
|
||
|
|
)
|
||
|
|
return n
|
||
|
|
|
||
|
|
|
||
|
|
def to_bytes_by_words(n: int, length: int) -> bytes:
|
||
|
|
"""
|
||
|
|
Converting int back to bytes by words.
|
||
|
|
"""
|
||
|
|
mask = (1 << (consts.WORD_SIZE * 8)) - 1
|
||
|
|
array = bytes()
|
||
|
|
for i in reversed(range(0, length, consts.WORD_SIZE)):
|
||
|
|
array = array + ((n >> (i * 8)) & mask).to_bytes(
|
||
|
|
consts.WORD_SIZE, sys.byteorder
|
||
|
|
)
|
||
|
|
return array
|
||
|
|
|
||
|
|
|
||
|
|
def int_to_word(n: int) -> bytes:
|
||
|
|
return n.to_bytes(consts.WORD_SIZE, sys.byteorder)
|
||
|
|
|
||
|
|
|
||
|
|
def word_to_int(b: bytes) -> int:
|
||
|
|
return int.from_bytes(b, sys.byteorder)
|