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# Copyright (c) Meta Platforms, Inc. and affiliates.
# SPDX-License-Identifier: LGPL-2.1-or-later
from tests import TestCase
from tests.libdrgn import deserialize_bits, serialize_bits
VALUE = 12345678912345678989
def py_serialize_bits(value, bit_offset, bit_size, little_endian):
bits = bit_offset + bit_size
size = (bits + 7) // 8
if little_endian:
tmp = value << bit_offset
else:
tmp = value << -bits % 8
# Buffer with unused bits set to zero.
buf0 = tmp.to_bytes(size, "little" if little_endian else "big")
# Buffer with unused bits set to one.
buf1 = bytearray(buf0)
if little_endian:
# bit_offset least significant bits.
buf1[0] |= (1 << bit_offset) - 1
# 8 - (bit_offset + bit_size) % 8 most significant bits.
buf1[-1] |= (0xFF00 >> -bits % 8) & 0xFF
else:
# bit_offset most significant bits.
buf1[0] |= (0xFF00 >> bit_offset) & 0xFF
# 8 - (bit_offset + bit_size) % 8 least significant bits.
buf1[-1] |= (1 << -bits % 8) - 1
return buf0, buf1
class TestSerialize(TestCase):
def test_deserialize(self):
for bit_size in range(1, 65):
expected = VALUE & ((1 << bit_size) - 1)
for bit_offset in range(8):
for little_endian in [True, False]:
for buf in py_serialize_bits(
expected, bit_offset, bit_size, little_endian
):
value = deserialize_bits(
buf, bit_offset, bit_size, little_endian
)
self.assertEqual(value, expected)
def test_serialize(self):
for bit_size in range(1, 65):
value = VALUE & ((1 << bit_size) - 1)
for bit_offset in range(8):
for little_endian in [True, False]:
expected0, expected1 = py_serialize_bits(
value, bit_offset, bit_size, little_endian
)
buf = bytearray(len(expected0))
serialize_bits(buf, bit_offset, value, bit_size, little_endian)
self.assertEqual(buf, expected0)
buf = bytearray([0xFF] * len(expected1))
serialize_bits(buf, bit_offset, value, bit_size, little_endian)
self.assertEqual(buf, expected1)
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