Buffered I/O implementation using an in-memory bytes buffer.
| 870 | |
| 871 | |
| 872 | class BytesIO(BufferedIOBase): |
| 873 | |
| 874 | """Buffered I/O implementation using an in-memory bytes buffer.""" |
| 875 | |
| 876 | # Initialize _buffer as soon as possible since it's used by __del__() |
| 877 | # which calls close() |
| 878 | _buffer = None |
| 879 | |
| 880 | def __init__(self, initial_bytes=None): |
| 881 | buf = bytearray() |
| 882 | if initial_bytes is not None: |
| 883 | buf += initial_bytes |
| 884 | self._buffer = buf |
| 885 | self._pos = 0 |
| 886 | |
| 887 | def __getstate__(self): |
| 888 | if self.closed: |
| 889 | raise ValueError("__getstate__ on closed file") |
| 890 | return self.__dict__.copy() |
| 891 | |
| 892 | def getvalue(self): |
| 893 | """Return the bytes value (contents) of the buffer |
| 894 | """ |
| 895 | if self.closed: |
| 896 | raise ValueError("getvalue on closed file") |
| 897 | return bytes(self._buffer) |
| 898 | |
| 899 | def getbuffer(self): |
| 900 | """Return a readable and writable view of the buffer. |
| 901 | """ |
| 902 | if self.closed: |
| 903 | raise ValueError("getbuffer on closed file") |
| 904 | return memoryview(self._buffer) |
| 905 | |
| 906 | def close(self): |
| 907 | if self._buffer is not None: |
| 908 | self._buffer.clear() |
| 909 | super().close() |
| 910 | |
| 911 | def read(self, size=-1): |
| 912 | if self.closed: |
| 913 | raise ValueError("read from closed file") |
| 914 | if size is None: |
| 915 | size = -1 |
| 916 | else: |
| 917 | try: |
| 918 | size_index = size.__index__ |
| 919 | except AttributeError: |
| 920 | raise TypeError(f"{size!r} is not an integer") |
| 921 | else: |
| 922 | size = size_index() |
| 923 | if size < 0: |
| 924 | size = len(self._buffer) |
| 925 | if len(self._buffer) <= self._pos: |
| 926 | return b"" |
| 927 | newpos = min(len(self._buffer), self._pos + size) |
| 928 | b = self._buffer[self._pos : newpos] |
| 929 | self._pos = newpos |
no outgoing calls