Inzynierka/Lib/site-packages/pandas/compat/compressors.py

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2023-06-02 12:51:02 +02:00
"""
Patched ``BZ2File`` and ``LZMAFile`` to handle pickle protocol 5.
"""
from __future__ import annotations
import bz2
from pickle import PickleBuffer
from pandas.compat._constants import PY310
try:
import lzma
has_lzma = True
except ImportError:
has_lzma = False
def flatten_buffer(
b: bytes | bytearray | memoryview | PickleBuffer,
) -> bytes | bytearray | memoryview:
"""
Return some 1-D `uint8` typed buffer.
Coerces anything that does not match that description to one that does
without copying if possible (otherwise will copy).
"""
if isinstance(b, (bytes, bytearray)):
return b
if not isinstance(b, PickleBuffer):
b = PickleBuffer(b)
try:
# coerce to 1-D `uint8` C-contiguous `memoryview` zero-copy
return b.raw()
except BufferError:
# perform in-memory copy if buffer is not contiguous
return memoryview(b).tobytes("A")
class BZ2File(bz2.BZ2File):
if not PY310:
def write(self, b) -> int:
# Workaround issue where `bz2.BZ2File` expects `len`
# to return the number of bytes in `b` by converting
# `b` into something that meets that constraint with
# minimal copying.
#
# Note: This is fixed in Python 3.10.
return super().write(flatten_buffer(b))
if has_lzma:
class LZMAFile(lzma.LZMAFile):
if not PY310:
def write(self, b) -> int:
# Workaround issue where `lzma.LZMAFile` expects `len`
# to return the number of bytes in `b` by converting
# `b` into something that meets that constraint with
# minimal copying.
#
# Note: This is fixed in Python 3.10.
return super().write(flatten_buffer(b))