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mirror of https://github.com/trezor/trezor-firmware.git synced 2024-11-12 10:39:00 +00:00
trezor-firmware/core/src/apps/common/writers.py

112 lines
2.6 KiB
Python

from trezor.utils import ensure
if False:
from trezor.utils import Writer
def empty_bytearray(preallocate: int) -> bytearray:
"""
Returns bytearray that won't allocate for at least `preallocate` bytes.
Useful in case you want to avoid allocating too often.
"""
b = bytearray(preallocate)
b[:] = bytes()
return b
def write_uint8(w: Writer, n: int) -> int:
ensure(0 <= n <= 0xFF)
w.append(n)
return 1
def write_uint16_le(w: Writer, n: int) -> int:
ensure(0 <= n <= 0xFFFF)
w.append(n & 0xFF)
w.append((n >> 8) & 0xFF)
return 2
def write_uint16_be(w: Writer, n: int) -> int:
ensure(0 <= n <= 0xFFFF)
w.append((n >> 8) & 0xFF)
w.append(n & 0xFF)
return 2
def write_uint32_le(w: Writer, n: int) -> int:
ensure(0 <= n <= 0xFFFF_FFFF)
w.append(n & 0xFF)
w.append((n >> 8) & 0xFF)
w.append((n >> 16) & 0xFF)
w.append((n >> 24) & 0xFF)
return 4
def write_uint32_be(w: Writer, n: int) -> int:
ensure(0 <= n <= 0xFFFF_FFFF)
w.append((n >> 24) & 0xFF)
w.append((n >> 16) & 0xFF)
w.append((n >> 8) & 0xFF)
w.append(n & 0xFF)
return 4
def write_uint64_le(w: Writer, n: int) -> int:
ensure(0 <= n <= 0xFFFF_FFFF_FFFF_FFFF)
w.append(n & 0xFF)
w.append((n >> 8) & 0xFF)
w.append((n >> 16) & 0xFF)
w.append((n >> 24) & 0xFF)
w.append((n >> 32) & 0xFF)
w.append((n >> 40) & 0xFF)
w.append((n >> 48) & 0xFF)
w.append((n >> 56) & 0xFF)
return 8
def write_uint64_be(w: Writer, n: int) -> int:
ensure(0 <= n <= 0xFFFF_FFFF_FFFF_FFFF)
w.append((n >> 56) & 0xFF)
w.append((n >> 48) & 0xFF)
w.append((n >> 40) & 0xFF)
w.append((n >> 32) & 0xFF)
w.append((n >> 24) & 0xFF)
w.append((n >> 16) & 0xFF)
w.append((n >> 8) & 0xFF)
w.append(n & 0xFF)
return 8
def write_bytes_unchecked(w: Writer, b: bytes) -> int:
w.extend(b)
return len(b)
def write_bytes_fixed(w: Writer, b: bytes, length: int) -> int:
ensure(len(b) == length)
w.extend(b)
return length
def write_bytes_reversed(w: Writer, b: bytes, length: int) -> int:
ensure(len(b) == length)
w.extend(bytes(reversed(b)))
return length
def write_bitcoin_varint(w: Writer, n: int) -> None:
ensure(n >= 0 and n <= 0xFFFF_FFFF)
if n < 253:
w.append(n & 0xFF)
elif n < 0x1_0000:
w.append(253)
w.append(n & 0xFF)
w.append((n >> 8) & 0xFF)
else:
w.append(254)
w.append(n & 0xFF)
w.append((n >> 8) & 0xFF)
w.append((n >> 16) & 0xFF)
w.append((n >> 24) & 0xFF)