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python3.2  3.2.2
Public Member Functions | Private Attributes
_pyio.BytesIO Class Reference
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List of all members.

Public Member Functions

def __init__
def __getstate__
def getvalue
def getbuffer
def read
def read1
def write
def seek
 Positioning ###.
def tell
def truncate
def readable
def writable
def seekable
 Inquiries ###.
def readinto
def detach
def flush
 Flush and close ###.
def close
def closed
def __enter__
 Context manager ###.
def __exit__
def fileno
 Lower-level APIs ###.
def isatty
def readline
 Readline[s] and writelines ###.
def __iter__
def __next__
def readlines
def writelines
def __new__
def register
def __instancecheck__
def __subclasscheck__

Private Attributes

 _buffer
 _pos

Detailed Description

Buffered I/O implementation using an in-memory bytes buffer.

Definition at line 783 of file _pyio.py.


Constructor & Destructor Documentation

def _pyio.BytesIO.__init__ (   self,
  initial_bytes = None 
)

Definition at line 787 of file _pyio.py.

00787 
00788     def __init__(self, initial_bytes=None):
00789         buf = bytearray()
00790         if initial_bytes is not None:
00791             buf += initial_bytes
00792         self._buffer = buf
00793         self._pos = 0

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Member Function Documentation

def _pyio.IOBase.__enter__ (   self) [inherited]

Context manager ###.

Context management protocol.  Returns self (an instance of IOBase).

Definition at line 419 of file _pyio.py.

00419 
00420     def __enter__(self):  # That's a forward reference
00421         """Context management protocol.  Returns self (an instance of IOBase)."""
00422         self._checkClosed()
00423         return self

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def _pyio.IOBase.__exit__ (   self,
  args 
) [inherited]
Context management protocol.  Calls close()

Definition at line 424 of file _pyio.py.

00424 
00425     def __exit__(self, *args):
00426         """Context management protocol.  Calls close()"""
00427         self.close()

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Definition at line 794 of file _pyio.py.

00794 
00795     def __getstate__(self):
00796         if self.closed:
00797             raise ValueError("__getstate__ on closed file")
00798         return self.__dict__.copy()

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def abc.ABCMeta.__instancecheck__ (   cls,
  instance 
) [inherited]
Override for isinstance(instance, cls).

Definition at line 158 of file abc.py.

00158 
00159     def __instancecheck__(cls, instance):
00160         """Override for isinstance(instance, cls)."""
00161         # Inline the cache checking
00162         subclass = instance.__class__
00163         if subclass in cls._abc_cache:
00164             return True
00165         subtype = type(instance)
00166         if subtype is subclass:
00167             if (cls._abc_negative_cache_version ==
00168                 ABCMeta._abc_invalidation_counter and
00169                 subclass in cls._abc_negative_cache):
00170                 return False
00171             # Fall back to the subclass check.
00172             return cls.__subclasscheck__(subclass)
00173         return any(cls.__subclasscheck__(c) for c in {subclass, subtype})

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def _pyio.IOBase.__iter__ (   self) [inherited]

Definition at line 486 of file _pyio.py.

00486 
00487     def __iter__(self):
00488         self._checkClosed()
00489         return self

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def abc.ABCMeta.__new__ (   mcls,
  name,
  bases,
  namespace 
) [inherited]

Definition at line 116 of file abc.py.

00116 
00117     def __new__(mcls, name, bases, namespace):
00118         cls = super().__new__(mcls, name, bases, namespace)
00119         # Compute set of abstract method names
00120         abstracts = {name
00121                      for name, value in namespace.items()
00122                      if getattr(value, "__isabstractmethod__", False)}
00123         for base in bases:
00124             for name in getattr(base, "__abstractmethods__", set()):
00125                 value = getattr(cls, name, None)
00126                 if getattr(value, "__isabstractmethod__", False):
00127                     abstracts.add(name)
00128         cls.__abstractmethods__ = frozenset(abstracts)
00129         # Set up inheritance registry
00130         cls._abc_registry = WeakSet()
00131         cls._abc_cache = WeakSet()
00132         cls._abc_negative_cache = WeakSet()
00133         cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
00134         return cls

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def _pyio.IOBase.__next__ (   self) [inherited]

Reimplemented in _pyio.TextIOWrapper.

Definition at line 490 of file _pyio.py.

00490 
00491     def __next__(self):
00492         line = self.readline()
00493         if not line:
00494             raise StopIteration
00495         return line

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def abc.ABCMeta.__subclasscheck__ (   cls,
  subclass 
) [inherited]
Override for issubclass(subclass, cls).

Definition at line 174 of file abc.py.

00174 
00175     def __subclasscheck__(cls, subclass):
00176         """Override for issubclass(subclass, cls)."""
00177         # Check cache
00178         if subclass in cls._abc_cache:
00179             return True
00180         # Check negative cache; may have to invalidate
00181         if cls._abc_negative_cache_version < ABCMeta._abc_invalidation_counter:
00182             # Invalidate the negative cache
00183             cls._abc_negative_cache = WeakSet()
00184             cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
00185         elif subclass in cls._abc_negative_cache:
00186             return False
00187         # Check the subclass hook
00188         ok = cls.__subclasshook__(subclass)
00189         if ok is not NotImplemented:
00190             assert isinstance(ok, bool)
00191             if ok:
00192                 cls._abc_cache.add(subclass)
00193             else:
00194                 cls._abc_negative_cache.add(subclass)
00195             return ok
00196         # Check if it's a direct subclass
00197         if cls in getattr(subclass, '__mro__', ()):
00198             cls._abc_cache.add(subclass)
00199             return True
00200         # Check if it's a subclass of a registered class (recursive)
00201         for rcls in cls._abc_registry:
00202             if issubclass(subclass, rcls):
00203                 cls._abc_cache.add(subclass)
00204                 return True
00205         # Check if it's a subclass of a subclass (recursive)
00206         for scls in cls.__subclasses__():
00207             if issubclass(subclass, scls):
00208                 cls._abc_cache.add(subclass)
00209                 return True
00210         # No dice; update negative cache
00211         cls._abc_negative_cache.add(subclass)
00212         return False

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def _pyio.IOBase.close (   self) [inherited]
Flush and close the IO object.

This method has no effect if the file is already closed.

Reimplemented in _pyio.TextIOWrapper, _pyio.BufferedRWPair, and _pyio._BufferedIOMixin.

Definition at line 336 of file _pyio.py.

00336 
00337     def close(self):
00338         """Flush and close the IO object.
00339 
00340         This method has no effect if the file is already closed.
00341         """
00342         if not self.__closed:
00343             self.flush()
00344             self.__closed = True

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def _pyio.IOBase.closed (   self) [inherited]
closed: bool.  True iff the file has been closed.

For backwards compatibility, this is a property, not a predicate.

Reimplemented in _pyio.TextIOWrapper, _pyio.BufferedRWPair, and _pyio._BufferedIOMixin.

Definition at line 403 of file _pyio.py.

00403 
00404     def closed(self):
00405         """closed: bool.  True iff the file has been closed.
00406 
00407         For backwards compatibility, this is a property, not a predicate.
00408         """
00409         return self.__closed

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def _pyio.BufferedIOBase.detach (   self) [inherited]
Separate the underlying raw stream from the buffer and return it.

After the raw stream has been detached, the buffer is in an unusable
state.

Reimplemented in _pyio._BufferedIOMixin.

Definition at line 664 of file _pyio.py.

00664 
00665     def detach(self):
00666         """
00667         Separate the underlying raw stream from the buffer and return it.
00668 
00669         After the raw stream has been detached, the buffer is in an unusable
00670         state.
00671         """
00672         self._unsupported("detach")
00673 
00674 io.BufferedIOBase.register(BufferedIOBase)
00675 

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def _pyio.IOBase.fileno (   self) [inherited]

Lower-level APIs ###.

Returns underlying file descriptor (an int) if one exists.

An IOError is raised if the IO object does not use a file descriptor.

Reimplemented in _pyio.TextIOWrapper, and _pyio._BufferedIOMixin.

Definition at line 432 of file _pyio.py.

00432 
00433     def fileno(self):
00434         """Returns underlying file descriptor (an int) if one exists.
00435 
00436         An IOError is raised if the IO object does not use a file descriptor.
00437         """
00438         self._unsupported("fileno")

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def _pyio.IOBase.flush (   self) [inherited]

Flush and close ###.

Flush write buffers, if applicable.

This is not implemented for read-only and non-blocking streams.

Reimplemented in _pyio.TextIOWrapper, _pyio.BufferedRWPair, _pyio.BufferedWriter, and _pyio._BufferedIOMixin.

Definition at line 326 of file _pyio.py.

00326 
00327     def flush(self):
00328         """Flush write buffers, if applicable.
00329 
00330         This is not implemented for read-only and non-blocking streams.
00331         """
00332         self._checkClosed()
00333         # XXX Should this return the number of bytes written???

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def _pyio.BytesIO.getbuffer (   self)
Return a readable and writable view of the buffer.

Definition at line 806 of file _pyio.py.

00806 
00807     def getbuffer(self):
00808         """Return a readable and writable view of the buffer.
00809         """
00810         return memoryview(self._buffer)

def _pyio.BytesIO.getvalue (   self)
Return the bytes value (contents) of the buffer

Definition at line 799 of file _pyio.py.

00799 
00800     def getvalue(self):
00801         """Return the bytes value (contents) of the buffer
00802         """
00803         if self.closed:
00804             raise ValueError("getvalue on closed file")
00805         return bytes(self._buffer)

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def _pyio.IOBase.isatty (   self) [inherited]
Return a bool indicating whether this is an 'interactive' stream.

Return False if it can't be determined.

Reimplemented in _pyio.TextIOWrapper, _pyio.BufferedRWPair, and _pyio._BufferedIOMixin.

Definition at line 439 of file _pyio.py.

00439 
00440     def isatty(self):
00441         """Return a bool indicating whether this is an 'interactive' stream.
00442 
00443         Return False if it can't be determined.
00444         """
00445         self._checkClosed()
00446         return False

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def _pyio.BytesIO.read (   self,
  n = None 
)
Read and return up to n bytes, where n is an int.

If the argument is omitted, None, or negative, reads and
returns all data until EOF.

If the argument is positive, and the underlying raw stream is
not 'interactive', multiple raw reads may be issued to satisfy
the byte count (unless EOF is reached first).  But for
interactive raw streams (XXX and for pipes?), at most one raw
read will be issued, and a short result does not imply that
EOF is imminent.

Returns an empty bytes array on EOF.

Raises BlockingIOError if the underlying raw stream has no
data at the moment.

Reimplemented from _pyio.BufferedIOBase.

Definition at line 811 of file _pyio.py.

00811 
00812     def read(self, n=None):
00813         if self.closed:
00814             raise ValueError("read from closed file")
00815         if n is None:
00816             n = -1
00817         if n < 0:
00818             n = len(self._buffer)
00819         if len(self._buffer) <= self._pos:
00820             return b""
00821         newpos = min(len(self._buffer), self._pos + n)
00822         b = self._buffer[self._pos : newpos]
00823         self._pos = newpos
00824         return bytes(b)

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def _pyio.BytesIO.read1 (   self,
  n 
)
This is the same as read.

Reimplemented from _pyio.BufferedIOBase.

Definition at line 825 of file _pyio.py.

00825 
00826     def read1(self, n):
00827         """This is the same as read.
00828         """
00829         return self.read(n)

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def _pyio.BytesIO.readable (   self)
Return a bool indicating whether object was opened for reading.

If False, read() will raise UnsupportedOperation.

Reimplemented from _pyio.IOBase.

Definition at line 887 of file _pyio.py.

00887 
00888     def readable(self):
00889         return True

def _pyio.BufferedIOBase.readinto (   self,
  b 
) [inherited]
Read up to len(b) bytes into bytearray b.

Like read(), this may issue multiple reads to the underlying raw
stream, unless the latter is 'interactive'.

Returns an int representing the number of bytes read (0 for EOF).

Raises BlockingIOError if the underlying raw stream has no
data at the moment.

Reimplemented in _pyio.BufferedRandom, and _pyio.BufferedRWPair.

Definition at line 630 of file _pyio.py.

00630 
00631     def readinto(self, b):
00632         """Read up to len(b) bytes into bytearray b.
00633 
00634         Like read(), this may issue multiple reads to the underlying raw
00635         stream, unless the latter is 'interactive'.
00636 
00637         Returns an int representing the number of bytes read (0 for EOF).
00638 
00639         Raises BlockingIOError if the underlying raw stream has no
00640         data at the moment.
00641         """
00642         # XXX This ought to work with anything that supports the buffer API
00643         data = self.read(len(b))
00644         n = len(data)
00645         try:
00646             b[:n] = data
00647         except TypeError as err:
00648             import array
00649             if not isinstance(b, array.array):
00650                 raise err
00651             b[:n] = array.array('b', data)
00652         return n

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def _pyio.IOBase.readline (   self,
  limit = -1 
) [inherited]

Readline[s] and writelines ###.

Reimplemented in _pyio.TextIOWrapper.

Definition at line 449 of file _pyio.py.

00449 
00450     def readline(self, limit=-1):
00451         r"""Read and return a line of bytes from the stream.
00452 
00453         If limit is specified, at most limit bytes will be read.
00454         Limit should be an int.
00455 
00456         The line terminator is always b'\n' for binary files; for text
00457         files, the newlines argument to open can be used to select the line
00458         terminator(s) recognized.
00459         """
00460         # For backwards compatibility, a (slowish) readline().
00461         if hasattr(self, "peek"):
00462             def nreadahead():
00463                 readahead = self.peek(1)
00464                 if not readahead:
00465                     return 1
00466                 n = (readahead.find(b"\n") + 1) or len(readahead)
00467                 if limit >= 0:
00468                     n = min(n, limit)
00469                 return n
00470         else:
00471             def nreadahead():
00472                 return 1
00473         if limit is None:
00474             limit = -1
00475         elif not isinstance(limit, int):
00476             raise TypeError("limit must be an integer")
00477         res = bytearray()
00478         while limit < 0 or len(res) < limit:
00479             b = self.read(nreadahead())
00480             if not b:
00481                 break
00482             res += b
00483             if res.endswith(b"\n"):
00484                 break
00485         return bytes(res)

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def _pyio.IOBase.readlines (   self,
  hint = None 
) [inherited]
Return a list of lines from the stream.

hint can be specified to control the number of lines read: no more
lines will be read if the total size (in bytes/characters) of all
lines so far exceeds hint.

Definition at line 496 of file _pyio.py.

00496 
00497     def readlines(self, hint=None):
00498         """Return a list of lines from the stream.
00499 
00500         hint can be specified to control the number of lines read: no more
00501         lines will be read if the total size (in bytes/characters) of all
00502         lines so far exceeds hint.
00503         """
00504         if hint is None or hint <= 0:
00505             return list(self)
00506         n = 0
00507         lines = []
00508         for line in self:
00509             lines.append(line)
00510             n += len(line)
00511             if n >= hint:
00512                 break
00513         return lines

def abc.ABCMeta.register (   cls,
  subclass 
) [inherited]
Register a virtual subclass of an ABC.

Definition at line 135 of file abc.py.

00135 
00136     def register(cls, subclass):
00137         """Register a virtual subclass of an ABC."""
00138         if not isinstance(subclass, type):
00139             raise TypeError("Can only register classes")
00140         if issubclass(subclass, cls):
00141             return  # Already a subclass
00142         # Subtle: test for cycles *after* testing for "already a subclass";
00143         # this means we allow X.register(X) and interpret it as a no-op.
00144         if issubclass(cls, subclass):
00145             # This would create a cycle, which is bad for the algorithm below
00146             raise RuntimeError("Refusing to create an inheritance cycle")
00147         cls._abc_registry.add(subclass)
00148         ABCMeta._abc_invalidation_counter += 1  # Invalidate negative cache

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def _pyio.BytesIO.seek (   self,
  pos,
  whence = 0 
)

Positioning ###.

Change stream position.

Change the stream position to byte offset offset. offset is
interpreted relative to the position indicated by whence.  Values
for whence are ints:

* 0 -- start of stream (the default); offset should be zero or positive
* 1 -- current stream position; offset may be negative
* 2 -- end of stream; offset is usually negative

Return an int indicating the new absolute position.

Reimplemented from _pyio.IOBase.

Definition at line 848 of file _pyio.py.

00848 
00849     def seek(self, pos, whence=0):
00850         if self.closed:
00851             raise ValueError("seek on closed file")
00852         try:
00853             pos.__index__
00854         except AttributeError as err:
00855             raise TypeError("an integer is required") from err
00856         if whence == 0:
00857             if pos < 0:
00858                 raise ValueError("negative seek position %r" % (pos,))
00859             self._pos = pos
00860         elif whence == 1:
00861             self._pos = max(0, self._pos + pos)
00862         elif whence == 2:
00863             self._pos = max(0, len(self._buffer) + pos)
00864         else:
00865             raise ValueError("invalid whence value")
00866         return self._pos

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def _pyio.BytesIO.seekable (   self)

Inquiries ###.

Return a bool indicating whether object supports random access.

If False, seek(), tell() and truncate() will raise UnsupportedOperation.
This method may need to do a test seek().

Reimplemented from _pyio.IOBase.

Definition at line 893 of file _pyio.py.

00893 
00894     def seekable(self):
00895         return True
00896 

def _pyio.BytesIO.tell (   self)
Return an int indicating the current stream position.

Reimplemented from _pyio.IOBase.

Definition at line 867 of file _pyio.py.

00867 
00868     def tell(self):
00869         if self.closed:
00870             raise ValueError("tell on closed file")
00871         return self._pos

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def _pyio.BytesIO.truncate (   self,
  pos = None 
)
Truncate file to size bytes.

Size defaults to the current IO position as reported by tell().  Return
the new size.

Reimplemented from _pyio.IOBase.

Definition at line 872 of file _pyio.py.

00872 
00873     def truncate(self, pos=None):
00874         if self.closed:
00875             raise ValueError("truncate on closed file")
00876         if pos is None:
00877             pos = self._pos
00878         else:
00879             try:
00880                 pos.__index__
00881             except AttributeError as err:
00882                 raise TypeError("an integer is required") from err
00883             if pos < 0:
00884                 raise ValueError("negative truncate position %r" % (pos,))
00885         del self._buffer[pos:]
00886         return pos

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def _pyio.BytesIO.writable (   self)
Return a bool indicating whether object was opened for writing.

If False, write() and truncate() will raise UnsupportedOperation.

Reimplemented from _pyio.IOBase.

Definition at line 890 of file _pyio.py.

00890 
00891     def writable(self):
00892         return True

def _pyio.BytesIO.write (   self,
  b 
)
Write the given bytes buffer to the IO stream.

Return the number of bytes written, which is never less than
len(b).

Raises BlockingIOError if the buffer is full and the
underlying raw stream cannot accept more data at the moment.

Reimplemented from _pyio.BufferedIOBase.

Definition at line 830 of file _pyio.py.

00830 
00831     def write(self, b):
00832         if self.closed:
00833             raise ValueError("write to closed file")
00834         if isinstance(b, str):
00835             raise TypeError("can't write str to binary stream")
00836         n = len(b)
00837         if n == 0:
00838             return 0
00839         pos = self._pos
00840         if pos > len(self._buffer):
00841             # Inserts null bytes between the current end of the file
00842             # and the new write position.
00843             padding = b'\x00' * (pos - len(self._buffer))
00844             self._buffer += padding
00845         self._buffer[pos:pos + n] = b
00846         self._pos += n
00847         return n

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def _pyio.IOBase.writelines (   self,
  lines 
) [inherited]

Definition at line 514 of file _pyio.py.

00514 
00515     def writelines(self, lines):
00516         self._checkClosed()
00517         for line in lines:
00518             self.write(line)
00519 
00520 io.IOBase.register(IOBase)
00521 


Member Data Documentation

Definition at line 791 of file _pyio.py.

_pyio.BytesIO._pos [private]

Definition at line 792 of file _pyio.py.


The documentation for this class was generated from the following file: