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# Copyright (c) Meta Platforms, Inc. and affiliates.
# SPDX-License-Identifier: LGPL-2.1-or-later
from collections import namedtuple
def _append_uleb128(buf, value):
assert value >= 0
while True:
byte = value & 0x7F
value >>= 7
if value:
buf.append(byte | 0x80)
else:
buf.append(byte)
break
def _append_sleb128(buf, value):
while True:
byte = value & 0x7F
value >>= 7
if (not value and not (byte & 0x40)) or (value == -1 and (byte & 0x40)):
buf.append(byte)
break
else:
buf.append(byte | 0x80)
U8 = namedtuple("U8", ["value"])
U8._append = lambda self, buf, byteorder: buf.append(self.value)
S8 = namedtuple("S8", ["value"])
S8._append = lambda self, buf, byteorder: buf.append(self.value & 0xFF)
U16 = namedtuple("U16", ["value"])
U16._append = lambda self, buf, byteorder: buf.extend(self.value.to_bytes(2, byteorder))
S16 = namedtuple("S16", ["value"])
S16._append = lambda self, buf, byteorder: buf.extend(
self.value.to_bytes(2, byteorder, signed=True)
)
U32 = namedtuple("U32", ["value"])
U32._append = lambda self, buf, byteorder: buf.extend(self.value.to_bytes(4, byteorder))
S32 = namedtuple("S32", ["value"])
S32._append = lambda self, buf, byteorder: buf.extend(
self.value.to_bytes(4, byteorder, signed=True)
)
U64 = namedtuple("U64", ["value"])
U64._append = lambda self, buf, byteorder: buf.extend(self.value.to_bytes(8, byteorder))
S64 = namedtuple("S64", ["value"])
S64._append = lambda self, buf, byteorder: buf.extend(
self.value.to_bytes(8, byteorder, signed=True)
)
ULEB128 = namedtuple("ULEB128", ["value"])
ULEB128._append = lambda self, buf, byteorder: _append_uleb128(buf, self.value)
SLEB128 = namedtuple("SLEB128", ["value"])
SLEB128._append = lambda self, buf, byteorder: _append_sleb128(buf, self.value)
def assemble(*args, little_endian=True):
byteorder = "little" if little_endian else "big"
buf = bytearray()
for arg in args:
if isinstance(arg, bytes):
buf.extend(arg)
else:
arg._append(buf, byteorder)
return buf
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