Merged revisions 61750,61752,61754,61756,61760,61763,61768,61772,61775,61805,61809,61812,61819,61917,61920,61930,61933-61934 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/trunk-bytearray
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r61750 | christian.heimes | 2008-03-22 20:47:44 +0100 (Sat, 22 Mar 2008) | 1 line
Copied files from py3k w/o modifications
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r61752 | christian.heimes | 2008-03-22 20:53:20 +0100 (Sat, 22 Mar 2008) | 7 lines
Take One
* Added initialization code, warnings, flags etc. to the appropriate places
* Added new buffer interface to string type
* Modified tests
* Modified Makefile.pre.in to compile the new files
* Added bytesobject.c to Python.h
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r61754 | christian.heimes | 2008-03-22 21:22:19 +0100 (Sat, 22 Mar 2008) | 2 lines
Disabled bytearray.extend for now since it causes an infinite recursion
Fixed serveral unit tests
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r61756 | christian.heimes | 2008-03-22 21:43:38 +0100 (Sat, 22 Mar 2008) | 5 lines
Added PyBytes support to several places:
str + bytearray
ord(bytearray)
bytearray(str, encoding)
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r61760 | christian.heimes | 2008-03-22 21:56:32 +0100 (Sat, 22 Mar 2008) | 1 line
Fixed more unit tests related to type('') is not unicode
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r61763 | christian.heimes | 2008-03-22 22:20:28 +0100 (Sat, 22 Mar 2008) | 2 lines
Fixed more unit tests
Fixed bytearray.extend
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r61768 | christian.heimes | 2008-03-22 22:40:50 +0100 (Sat, 22 Mar 2008) | 1 line
Implemented old buffer interface for bytearray
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r61772 | christian.heimes | 2008-03-22 23:24:52 +0100 (Sat, 22 Mar 2008) | 1 line
Added backport of the io module
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r61775 | christian.heimes | 2008-03-23 03:50:49 +0100 (Sun, 23 Mar 2008) | 1 line
Fix str assignement to bytearray. Assignment of a str of size 1 is interpreted as a single byte
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r61805 | christian.heimes | 2008-03-23 19:33:48 +0100 (Sun, 23 Mar 2008) | 3 lines
Fixed more tests
Fixed bytearray() comparsion with unicode()
Fixed iterator assignment of bytearray
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r61809 | christian.heimes | 2008-03-23 21:02:21 +0100 (Sun, 23 Mar 2008) | 2 lines
str(bytesarray()) now returns the bytes and not the representation of the bytearray object
Enabled and fixed more unit tests
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r61812 | christian.heimes | 2008-03-23 21:53:08 +0100 (Sun, 23 Mar 2008) | 3 lines
Clear error PyNumber_AsSsize_t() fails
Use CHARMASK for ob_svall access
disabled a test with memoryview again
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r61819 | christian.heimes | 2008-03-23 23:05:57 +0100 (Sun, 23 Mar 2008) | 1 line
Untested updates to the PCBuild directory
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r61917 | christian.heimes | 2008-03-26 00:57:06 +0100 (Wed, 26 Mar 2008) | 1 line
The type system of Python 2.6 has subtle differences to 3.0's. I've removed the Py_TPFLAGS_BASETYPE flags from bytearray for now. bytearray can't be subclasses until the issues with bytearray subclasses are fixed.
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r61920 | christian.heimes | 2008-03-26 01:44:08 +0100 (Wed, 26 Mar 2008) | 2 lines
Disabled last failing test
I don't understand what the test is testing and how it suppose to work. Ka-Ping, please check it out.
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r61930 | christian.heimes | 2008-03-26 12:46:18 +0100 (Wed, 26 Mar 2008) | 1 line
Re-enabled bytes warning code
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r61933 | christian.heimes | 2008-03-26 13:20:46 +0100 (Wed, 26 Mar 2008) | 1 line
Fixed a bug in the new buffer protocol. The buffer slots weren't copied into a subclass.
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r61934 | christian.heimes | 2008-03-26 13:25:09 +0100 (Wed, 26 Mar 2008) | 1 line
Re-enabled bytearray subclassing - all tests are passing.
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diff --git a/Lib/io.py b/Lib/io.py
new file mode 100644
index 0000000..334b34c
--- /dev/null
+++ b/Lib/io.py
@@ -0,0 +1,1601 @@
+"""New I/O library conforming to PEP 3116.
+
+This is a prototype; hopefully eventually some of this will be
+reimplemented in C.
+
+Conformance of alternative implementations: all arguments are intended
+to be positional-only except the arguments of the open() function.
+Argument names except those of the open() function are not part of the
+specification. Instance variables and methods whose name starts with
+a leading underscore are not part of the specification (except "magic"
+names like __iter__). Only the top-level names listed in the __all__
+variable are part of the specification.
+
+XXX edge cases when switching between reading/writing
+XXX need to support 1 meaning line-buffered
+XXX whenever an argument is None, use the default value
+XXX read/write ops should check readable/writable
+XXX buffered readinto should work with arbitrary buffer objects
+XXX use incremental encoder for text output, at least for UTF-16 and UTF-8-SIG
+XXX check writable, readable and seekable in appropriate places
+"""
+
+__author__ = ("Guido van Rossum <guido@python.org>, "
+ "Mike Verdone <mike.verdone@gmail.com>, "
+ "Mark Russell <mark.russell@zen.co.uk>")
+
+__all__ = ["BlockingIOError", "open", "IOBase", "RawIOBase", "FileIO",
+ "BytesIO", "StringIO", "BufferedIOBase",
+ "BufferedReader", "BufferedWriter", "BufferedRWPair",
+ "BufferedRandom", "TextIOBase", "TextIOWrapper"]
+
+import os
+import abc
+import sys
+import codecs
+import _fileio
+import warnings
+
+# open() uses st_blksize whenever we can
+DEFAULT_BUFFER_SIZE = 8 * 1024 # bytes
+
+# py3k has only new style classes
+__metaclass__ = type
+
+class BlockingIOError(IOError):
+
+ """Exception raised when I/O would block on a non-blocking I/O stream."""
+
+ def __init__(self, errno, strerror, characters_written=0):
+ IOError.__init__(self, errno, strerror)
+ self.characters_written = characters_written
+
+
+def open(file, mode="r", buffering=None, encoding=None, errors=None,
+ newline=None, closefd=True):
+ r"""Replacement for the built-in open function.
+
+ Args:
+ file: string giving the name of the file to be opened;
+ or integer file descriptor of the file to be wrapped (*).
+ mode: optional mode string; see below.
+ buffering: optional int >= 0 giving the buffer size; values
+ can be: 0 = unbuffered, 1 = line buffered,
+ larger = fully buffered.
+ encoding: optional string giving the text encoding.
+ errors: optional string giving the encoding error handling.
+ newline: optional newlines specifier; must be None, '', '\n', '\r'
+ or '\r\n'; all other values are illegal. It controls the
+ handling of line endings. It works as follows:
+
+ * On input, if `newline` is `None`, universal newlines
+ mode is enabled. Lines in the input can end in `'\n'`,
+ `'\r'`, or `'\r\n'`, and these are translated into
+ `'\n'` before being returned to the caller. If it is
+ `''`, universal newline mode is enabled, but line endings
+ are returned to the caller untranslated. If it has any of
+ the other legal values, input lines are only terminated by
+ the given string, and the line ending is returned to the
+ caller untranslated.
+
+ * On output, if `newline` is `None`, any `'\n'`
+ characters written are translated to the system default
+ line separator, `os.linesep`. If `newline` is `''`,
+ no translation takes place. If `newline` is any of the
+ other legal values, any `'\n'` characters written are
+ translated to the given string.
+
+ closefd: optional argument to keep the underlying file descriptor
+ open when the file is closed. It must not be false when
+ a filename is given.
+
+ (*) If a file descriptor is given, it is closed when the returned
+ I/O object is closed, unless closefd=False is given.
+
+ Mode strings characters:
+ 'r': open for reading (default)
+ 'w': open for writing, truncating the file first
+ 'a': open for writing, appending to the end if the file exists
+ 'b': binary mode
+ 't': text mode (default)
+ '+': open a disk file for updating (implies reading and writing)
+ 'U': universal newline mode (for backwards compatibility)
+
+ Constraints:
+ - encoding or errors must not be given when a binary mode is given
+ - buffering must not be zero when a text mode is given
+
+ Returns:
+ Depending on the mode and buffering arguments, either a raw
+ binary stream, a buffered binary stream, or a buffered text
+ stream, open for reading and/or writing.
+ """
+ if not isinstance(file, (str, unicode, int)):
+ raise TypeError("invalid file: %r" % file)
+ if not isinstance(mode, str):
+ raise TypeError("invalid mode: %r" % mode)
+ if buffering is not None and not isinstance(buffering, int):
+ raise TypeError("invalid buffering: %r" % buffering)
+ if encoding is not None and not isinstance(encoding, str):
+ raise TypeError("invalid encoding: %r" % encoding)
+ if errors is not None and not isinstance(errors, str):
+ raise TypeError("invalid errors: %r" % errors)
+ modes = set(mode)
+ if modes - set("arwb+tU") or len(mode) > len(modes):
+ raise ValueError("invalid mode: %r" % mode)
+ reading = "r" in modes
+ writing = "w" in modes
+ appending = "a" in modes
+ updating = "+" in modes
+ text = "t" in modes
+ binary = "b" in modes
+ if "U" in modes:
+ if writing or appending:
+ raise ValueError("can't use U and writing mode at once")
+ reading = True
+ if text and binary:
+ raise ValueError("can't have text and binary mode at once")
+ if reading + writing + appending > 1:
+ raise ValueError("can't have read/write/append mode at once")
+ if not (reading or writing or appending):
+ raise ValueError("must have exactly one of read/write/append mode")
+ if binary and encoding is not None:
+ raise ValueError("binary mode doesn't take an encoding argument")
+ if binary and errors is not None:
+ raise ValueError("binary mode doesn't take an errors argument")
+ if binary and newline is not None:
+ raise ValueError("binary mode doesn't take a newline argument")
+ raw = FileIO(file,
+ (reading and "r" or "") +
+ (writing and "w" or "") +
+ (appending and "a" or "") +
+ (updating and "+" or ""),
+ closefd)
+ if buffering is None:
+ buffering = -1
+ line_buffering = False
+ if buffering == 1 or buffering < 0 and raw.isatty():
+ buffering = -1
+ line_buffering = True
+ if buffering < 0:
+ buffering = DEFAULT_BUFFER_SIZE
+ try:
+ bs = os.fstat(raw.fileno()).st_blksize
+ except (os.error, AttributeError):
+ pass
+ else:
+ if bs > 1:
+ buffering = bs
+ if buffering < 0:
+ raise ValueError("invalid buffering size")
+ if buffering == 0:
+ if binary:
+ raw._name = file
+ raw._mode = mode
+ return raw
+ raise ValueError("can't have unbuffered text I/O")
+ if updating:
+ buffer = BufferedRandom(raw, buffering)
+ elif writing or appending:
+ buffer = BufferedWriter(raw, buffering)
+ elif reading:
+ buffer = BufferedReader(raw, buffering)
+ else:
+ raise ValueError("unknown mode: %r" % mode)
+ if binary:
+ buffer.name = file
+ buffer.mode = mode
+ return buffer
+ text = TextIOWrapper(buffer, encoding, errors, newline, line_buffering)
+ text.name = file
+ text.mode = mode
+ return text
+
+class _DocDescriptor:
+ """Helper for builtins.open.__doc__
+ """
+ def __get__(self, obj, typ):
+ return (
+ "open(file, mode='r', buffering=None, encoding=None, "
+ "errors=None, newline=None, closefd=True)\n\n" +
+ open.__doc__)
+
+class OpenWrapper:
+ """Wrapper for builtins.open
+
+ Trick so that open won't become a bound method when stored
+ as a class variable (as dumbdbm does).
+
+ See initstdio() in Python/pythonrun.c.
+ """
+ __doc__ = _DocDescriptor()
+
+ def __new__(cls, *args, **kwargs):
+ return open(*args, **kwargs)
+
+
+class UnsupportedOperation(ValueError, IOError):
+ pass
+
+
+class IOBase(object):
+
+ """Base class for all I/O classes.
+
+ This class provides dummy implementations for many methods that
+ derived classes can override selectively; the default
+ implementations represent a file that cannot be read, written or
+ seeked.
+
+ This does not define read(), readinto() and write(), nor
+ readline() and friends, since their signatures vary per layer.
+
+ Not that calling any method (even inquiries) on a closed file is
+ undefined. Implementations may raise IOError in this case.
+ """
+
+ __metaclass__ = abc.ABCMeta
+
+ ### Internal ###
+
+ def _unsupported(self, name):
+ """Internal: raise an exception for unsupported operations."""
+ raise UnsupportedOperation("%s.%s() not supported" %
+ (self.__class__.__name__, name))
+
+ ### Positioning ###
+
+ def seek(self, pos, whence = 0):
+ """seek(pos: int, whence: int = 0) -> int. Change stream position.
+
+ Seek to byte offset pos relative to position indicated by whence:
+ 0 Start of stream (the default). pos should be >= 0;
+ 1 Current position - whence may be negative;
+ 2 End of stream - whence usually negative.
+ Returns the new absolute position.
+ """
+ self._unsupported("seek")
+
+ def tell(self):
+ """tell() -> int. Return current stream position."""
+ return self.seek(0, 1)
+
+ def truncate(self, pos = None):
+ """truncate(size: int = None) -> int. Truncate file to size bytes.
+
+ Size defaults to the current IO position as reported by tell().
+ Returns the new size.
+ """
+ self._unsupported("truncate")
+
+ ### Flush and close ###
+
+ def flush(self):
+ """flush() -> None. Flushes write buffers, if applicable.
+
+ This is a no-op for read-only and non-blocking streams.
+ """
+ # XXX Should this return the number of bytes written???
+
+ __closed = False
+
+ def close(self):
+ """close() -> None. Flushes and closes the IO object.
+
+ This must be idempotent. It should also set a flag for the
+ 'closed' property (see below) to test.
+ """
+ if not self.__closed:
+ try:
+ self.flush()
+ except IOError:
+ pass # If flush() fails, just give up
+ self.__closed = True
+
+ def __del__(self):
+ """Destructor. Calls close()."""
+ # The try/except block is in case this is called at program
+ # exit time, when it's possible that globals have already been
+ # deleted, and then the close() call might fail. Since
+ # there's nothing we can do about such failures and they annoy
+ # the end users, we suppress the traceback.
+ try:
+ self.close()
+ except:
+ pass
+
+ ### Inquiries ###
+
+ def seekable(self):
+ """seekable() -> bool. Return whether object supports random access.
+
+ If False, seek(), tell() and truncate() will raise IOError.
+ This method may need to do a test seek().
+ """
+ return False
+
+ def _checkSeekable(self, msg=None):
+ """Internal: raise an IOError if file is not seekable
+ """
+ if not self.seekable():
+ raise IOError("File or stream is not seekable."
+ if msg is None else msg)
+
+
+ def readable(self):
+ """readable() -> bool. Return whether object was opened for reading.
+
+ If False, read() will raise IOError.
+ """
+ return False
+
+ def _checkReadable(self, msg=None):
+ """Internal: raise an IOError if file is not readable
+ """
+ if not self.readable():
+ raise IOError("File or stream is not readable."
+ if msg is None else msg)
+
+ def writable(self):
+ """writable() -> bool. Return whether object was opened for writing.
+
+ If False, write() and truncate() will raise IOError.
+ """
+ return False
+
+ def _checkWritable(self, msg=None):
+ """Internal: raise an IOError if file is not writable
+ """
+ if not self.writable():
+ raise IOError("File or stream is not writable."
+ if msg is None else msg)
+
+ @property
+ def closed(self):
+ """closed: bool. True iff the file has been closed.
+
+ For backwards compatibility, this is a property, not a predicate.
+ """
+ return self.__closed
+
+ def _checkClosed(self, msg=None):
+ """Internal: raise an ValueError if file is closed
+ """
+ if self.closed:
+ raise ValueError("I/O operation on closed file."
+ if msg is None else msg)
+
+ ### Context manager ###
+
+ def __enter__(self):
+ """Context management protocol. Returns self."""
+ self._checkClosed()
+ return self
+
+ def __exit__(self, *args):
+ """Context management protocol. Calls close()"""
+ self.close()
+
+ ### Lower-level APIs ###
+
+ # XXX Should these be present even if unimplemented?
+
+ def fileno(self):
+ """fileno() -> int. Returns underlying file descriptor if one exists.
+
+ Raises IOError if the IO object does not use a file descriptor.
+ """
+ self._unsupported("fileno")
+
+ def isatty(self):
+ """isatty() -> int. Returns whether this is an 'interactive' stream.
+
+ Returns False if we don't know.
+ """
+ self._checkClosed()
+ return False
+
+ ### Readline[s] and writelines ###
+
+ def readline(self, limit = -1):
+ """For backwards compatibility, a (slowish) readline()."""
+ if hasattr(self, "peek"):
+ def nreadahead():
+ readahead = self.peek(1)
+ if not readahead:
+ return 1
+ n = (readahead.find(b"\n") + 1) or len(readahead)
+ if limit >= 0:
+ n = min(n, limit)
+ return n
+ else:
+ def nreadahead():
+ return 1
+ if limit is None:
+ limit = -1
+ res = bytearray()
+ while limit < 0 or len(res) < limit:
+ b = self.read(nreadahead())
+ if not b:
+ break
+ res += b
+ if res.endswith(b"\n"):
+ break
+ return bytes(res)
+
+ def __iter__(self):
+ self._checkClosed()
+ return self
+
+ def next(self):
+ line = self.readline()
+ if not line:
+ raise StopIteration
+ return line
+
+ def readlines(self, hint=None):
+ if hint is None:
+ return list(self)
+ n = 0
+ lines = []
+ for line in self:
+ lines.append(line)
+ n += len(line)
+ if n >= hint:
+ break
+ return lines
+
+ def writelines(self, lines):
+ self._checkClosed()
+ for line in lines:
+ self.write(line)
+
+
+class RawIOBase(IOBase):
+
+ """Base class for raw binary I/O.
+
+ The read() method is implemented by calling readinto(); derived
+ classes that want to support read() only need to implement
+ readinto() as a primitive operation. In general, readinto()
+ can be more efficient than read().
+
+ (It would be tempting to also provide an implementation of
+ readinto() in terms of read(), in case the latter is a more
+ suitable primitive operation, but that would lead to nasty
+ recursion in case a subclass doesn't implement either.)
+ """
+
+ def read(self, n = -1):
+ """read(n: int) -> bytes. Read and return up to n bytes.
+
+ Returns an empty bytes array on EOF, or None if the object is
+ set not to block and has no data to read.
+ """
+ if n is None:
+ n = -1
+ if n < 0:
+ return self.readall()
+ b = bytearray(n.__index__())
+ n = self.readinto(b)
+ del b[n:]
+ return bytes(b)
+
+ def readall(self):
+ """readall() -> bytes. Read until EOF, using multiple read() call."""
+ res = bytearray()
+ while True:
+ data = self.read(DEFAULT_BUFFER_SIZE)
+ if not data:
+ break
+ res += data
+ return bytes(res)
+
+ def readinto(self, b):
+ """readinto(b: bytes) -> int. Read up to len(b) bytes into b.
+
+ Returns number of bytes read (0 for EOF), or None if the object
+ is set not to block as has no data to read.
+ """
+ self._unsupported("readinto")
+
+ def write(self, b):
+ """write(b: bytes) -> int. Write the given buffer to the IO stream.
+
+ Returns the number of bytes written, which may be less than len(b).
+ """
+ self._unsupported("write")
+
+
+class FileIO(_fileio._FileIO, RawIOBase):
+
+ """Raw I/O implementation for OS files.
+
+ This multiply inherits from _FileIO and RawIOBase to make
+ isinstance(io.FileIO(), io.RawIOBase) return True without
+ requiring that _fileio._FileIO inherits from io.RawIOBase (which
+ would be hard to do since _fileio.c is written in C).
+ """
+
+ def close(self):
+ _fileio._FileIO.close(self)
+ RawIOBase.close(self)
+
+ @property
+ def name(self):
+ return self._name
+
+ @property
+ def mode(self):
+ return self._mode
+
+
+class BufferedIOBase(IOBase):
+
+ """Base class for buffered IO objects.
+
+ The main difference with RawIOBase is that the read() method
+ supports omitting the size argument, and does not have a default
+ implementation that defers to readinto().
+
+ In addition, read(), readinto() and write() may raise
+ BlockingIOError if the underlying raw stream is in non-blocking
+ mode and not ready; unlike their raw counterparts, they will never
+ return None.
+
+ A typical implementation should not inherit from a RawIOBase
+ implementation, but wrap one.
+ """
+
+ def read(self, n = None):
+ """read(n: int = None) -> bytes. Read and return up to n bytes.
+
+ 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.
+ """
+ self._unsupported("read")
+
+ def readinto(self, b):
+ """readinto(b: bytes) -> int. Read up to len(b) bytes into b.
+
+ Like read(), this may issue multiple reads to the underlying
+ raw stream, unless the latter is 'interactive' (XXX or a
+ pipe?).
+
+ Returns the number of bytes read (0 for EOF).
+
+ Raises BlockingIOError if the underlying raw stream has no
+ data at the moment.
+ """
+ # XXX This ought to work with anything that supports the buffer API
+ data = self.read(len(b))
+ n = len(data)
+ try:
+ b[:n] = data
+ except TypeError as err:
+ import array
+ if not isinstance(b, array.array):
+ raise err
+ b[:n] = array.array('b', data)
+ return n
+
+ def write(self, b):
+ """write(b: bytes) -> int. Write the given buffer to the IO stream.
+
+ Returns 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.
+ """
+ self._unsupported("write")
+
+
+class _BufferedIOMixin(BufferedIOBase):
+
+ """A mixin implementation of BufferedIOBase with an underlying raw stream.
+
+ This passes most requests on to the underlying raw stream. It
+ does *not* provide implementations of read(), readinto() or
+ write().
+ """
+
+ def __init__(self, raw):
+ self.raw = raw
+
+ ### Positioning ###
+
+ def seek(self, pos, whence=0):
+ return self.raw.seek(pos, whence)
+
+ def tell(self):
+ return self.raw.tell()
+
+ def truncate(self, pos=None):
+ # Flush the stream. We're mixing buffered I/O with lower-level I/O,
+ # and a flush may be necessary to synch both views of the current
+ # file state.
+ self.flush()
+
+ if pos is None:
+ pos = self.tell()
+ return self.raw.truncate(pos)
+
+ ### Flush and close ###
+
+ def flush(self):
+ self.raw.flush()
+
+ def close(self):
+ if not self.closed:
+ try:
+ self.flush()
+ except IOError:
+ pass # If flush() fails, just give up
+ self.raw.close()
+
+ ### Inquiries ###
+
+ def seekable(self):
+ return self.raw.seekable()
+
+ def readable(self):
+ return self.raw.readable()
+
+ def writable(self):
+ return self.raw.writable()
+
+ @property
+ def closed(self):
+ return self.raw.closed
+
+ ### Lower-level APIs ###
+
+ def fileno(self):
+ return self.raw.fileno()
+
+ def isatty(self):
+ return self.raw.isatty()
+
+
+class BytesIO(BufferedIOBase):
+
+ """Buffered I/O implementation using an in-memory bytes buffer."""
+
+ # XXX More docs
+
+ def __init__(self, initial_bytes=None):
+ buf = bytearray()
+ if initial_bytes is not None:
+ buf += initial_bytes
+ self._buffer = buf
+ self._pos = 0
+
+ def getvalue(self):
+ return bytes(self._buffer)
+
+ def read(self, n=None):
+ if n is None:
+ n = -1
+ if n < 0:
+ n = len(self._buffer)
+ newpos = min(len(self._buffer), self._pos + n)
+ b = self._buffer[self._pos : newpos]
+ self._pos = newpos
+ return bytes(b)
+
+ def read1(self, n):
+ return self.read(n)
+
+ def write(self, b):
+ if self.closed:
+ raise ValueError("write to closed file")
+ if isinstance(b, unicode):
+ raise TypeError("can't write unicode to binary stream")
+ n = len(b)
+ newpos = self._pos + n
+ if newpos > len(self._buffer):
+ # Inserts null bytes between the current end of the file
+ # and the new write position.
+ padding = b'\x00' * (newpos - len(self._buffer) - n)
+ self._buffer[self._pos:newpos - n] = padding
+ self._buffer[self._pos:newpos] = b
+ self._pos = newpos
+ return n
+
+ def seek(self, pos, whence=0):
+ try:
+ pos = pos.__index__()
+ except AttributeError as err:
+ raise TypeError("an integer is required") # from err
+ if whence == 0:
+ self._pos = max(0, pos)
+ elif whence == 1:
+ self._pos = max(0, self._pos + pos)
+ elif whence == 2:
+ self._pos = max(0, len(self._buffer) + pos)
+ else:
+ raise IOError("invalid whence value")
+ return self._pos
+
+ def tell(self):
+ return self._pos
+
+ def truncate(self, pos=None):
+ if pos is None:
+ pos = self._pos
+ del self._buffer[pos:]
+ return pos
+
+ def readable(self):
+ return True
+
+ def writable(self):
+ return True
+
+ def seekable(self):
+ return True
+
+
+class BufferedReader(_BufferedIOMixin):
+
+ """Buffer for a readable sequential RawIO object."""
+
+ def __init__(self, raw, buffer_size=DEFAULT_BUFFER_SIZE):
+ """Create a new buffered reader using the given readable raw IO object.
+ """
+ raw._checkReadable()
+ _BufferedIOMixin.__init__(self, raw)
+ self._read_buf = b""
+ self.buffer_size = buffer_size
+
+ def read(self, n=None):
+ """Read n bytes.
+
+ Returns exactly n bytes of data unless the underlying raw IO
+ stream reaches EOF or if the call would block in non-blocking
+ mode. If n is negative, read until EOF or until read() would
+ block.
+ """
+ if n is None:
+ n = -1
+ nodata_val = b""
+ while n < 0 or len(self._read_buf) < n:
+ to_read = max(self.buffer_size,
+ n if n is not None else 2*len(self._read_buf))
+ current = self.raw.read(to_read)
+ if current in (b"", None):
+ nodata_val = current
+ break
+ self._read_buf += current
+ if self._read_buf:
+ if n < 0:
+ n = len(self._read_buf)
+ out = self._read_buf[:n]
+ self._read_buf = self._read_buf[n:]
+ else:
+ out = nodata_val
+ return out
+
+ def peek(self, n=0):
+ """Returns buffered bytes without advancing the position.
+
+ The argument indicates a desired minimal number of bytes; we
+ do at most one raw read to satisfy it. We never return more
+ than self.buffer_size.
+ """
+ want = min(n, self.buffer_size)
+ have = len(self._read_buf)
+ if have < want:
+ to_read = self.buffer_size - have
+ current = self.raw.read(to_read)
+ if current:
+ self._read_buf += current
+ return self._read_buf
+
+ def read1(self, n):
+ """Reads up to n bytes, with at most one read() system call.
+
+ Returns up to n bytes. If at least one byte is buffered, we
+ only return buffered bytes. Otherwise, we do one raw read.
+ """
+ if n <= 0:
+ return b""
+ self.peek(1)
+ return self.read(min(n, len(self._read_buf)))
+
+ def tell(self):
+ return self.raw.tell() - len(self._read_buf)
+
+ def seek(self, pos, whence=0):
+ if whence == 1:
+ pos -= len(self._read_buf)
+ pos = self.raw.seek(pos, whence)
+ self._read_buf = b""
+ return pos
+
+
+class BufferedWriter(_BufferedIOMixin):
+
+ # XXX docstring
+
+ def __init__(self, raw,
+ buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
+ raw._checkWritable()
+ _BufferedIOMixin.__init__(self, raw)
+ self.buffer_size = buffer_size
+ self.max_buffer_size = (2*buffer_size
+ if max_buffer_size is None
+ else max_buffer_size)
+ self._write_buf = bytearray()
+
+ def write(self, b):
+ if self.closed:
+ raise ValueError("write to closed file")
+ if isinstance(b, unicode):
+ raise TypeError("can't write unicode to binary stream")
+ # XXX we can implement some more tricks to try and avoid partial writes
+ if len(self._write_buf) > self.buffer_size:
+ # We're full, so let's pre-flush the buffer
+ try:
+ self.flush()
+ except BlockingIOError as e:
+ # We can't accept anything else.
+ # XXX Why not just let the exception pass through?
+ raise BlockingIOError(e.errno, e.strerror, 0)
+ before = len(self._write_buf)
+ self._write_buf.extend(b)
+ written = len(self._write_buf) - before
+ if len(self._write_buf) > self.buffer_size:
+ try:
+ self.flush()
+ except BlockingIOError as e:
+ if (len(self._write_buf) > self.max_buffer_size):
+ # We've hit max_buffer_size. We have to accept a partial
+ # write and cut back our buffer.
+ overage = len(self._write_buf) - self.max_buffer_size
+ self._write_buf = self._write_buf[:self.max_buffer_size]
+ raise BlockingIOError(e.errno, e.strerror, overage)
+ return written
+
+ def flush(self):
+ if self.closed:
+ raise ValueError("flush of closed file")
+ written = 0
+ try:
+ while self._write_buf:
+ n = self.raw.write(self._write_buf)
+ del self._write_buf[:n]
+ written += n
+ except BlockingIOError as e:
+ n = e.characters_written
+ del self._write_buf[:n]
+ written += n
+ raise BlockingIOError(e.errno, e.strerror, written)
+
+ def tell(self):
+ return self.raw.tell() + len(self._write_buf)
+
+ def seek(self, pos, whence=0):
+ self.flush()
+ return self.raw.seek(pos, whence)
+
+
+class BufferedRWPair(BufferedIOBase):
+
+ """A buffered reader and writer object together.
+
+ A buffered reader object and buffered writer object put together
+ to form a sequential IO object that can read and write.
+
+ This is typically used with a socket or two-way pipe.
+
+ XXX The usefulness of this (compared to having two separate IO
+ objects) is questionable.
+ """
+
+ def __init__(self, reader, writer,
+ buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
+ """Constructor.
+
+ The arguments are two RawIO instances.
+ """
+ reader._checkReadable()
+ writer._checkWritable()
+ self.reader = BufferedReader(reader, buffer_size)
+ self.writer = BufferedWriter(writer, buffer_size, max_buffer_size)
+
+ def read(self, n=None):
+ if n is None:
+ n = -1
+ return self.reader.read(n)
+
+ def readinto(self, b):
+ return self.reader.readinto(b)
+
+ def write(self, b):
+ return self.writer.write(b)
+
+ def peek(self, n=0):
+ return self.reader.peek(n)
+
+ def read1(self, n):
+ return self.reader.read1(n)
+
+ def readable(self):
+ return self.reader.readable()
+
+ def writable(self):
+ return self.writer.writable()
+
+ def flush(self):
+ return self.writer.flush()
+
+ def close(self):
+ self.writer.close()
+ self.reader.close()
+
+ def isatty(self):
+ return self.reader.isatty() or self.writer.isatty()
+
+ @property
+ def closed(self):
+ return self.writer.closed()
+
+
+class BufferedRandom(BufferedWriter, BufferedReader):
+
+ # XXX docstring
+
+ def __init__(self, raw,
+ buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
+ raw._checkSeekable()
+ BufferedReader.__init__(self, raw, buffer_size)
+ BufferedWriter.__init__(self, raw, buffer_size, max_buffer_size)
+
+ def seek(self, pos, whence=0):
+ self.flush()
+ # First do the raw seek, then empty the read buffer, so that
+ # if the raw seek fails, we don't lose buffered data forever.
+ pos = self.raw.seek(pos, whence)
+ self._read_buf = b""
+ return pos
+
+ def tell(self):
+ if (self._write_buf):
+ return self.raw.tell() + len(self._write_buf)
+ else:
+ return self.raw.tell() - len(self._read_buf)
+
+ def read(self, n=None):
+ if n is None:
+ n = -1
+ self.flush()
+ return BufferedReader.read(self, n)
+
+ def readinto(self, b):
+ self.flush()
+ return BufferedReader.readinto(self, b)
+
+ def peek(self, n=0):
+ self.flush()
+ return BufferedReader.peek(self, n)
+
+ def read1(self, n):
+ self.flush()
+ return BufferedReader.read1(self, n)
+
+ def write(self, b):
+ if self._read_buf:
+ self.raw.seek(-len(self._read_buf), 1) # Undo readahead
+ self._read_buf = b""
+ return BufferedWriter.write(self, b)
+
+
+class TextIOBase(IOBase):
+
+ """Base class for text I/O.
+
+ This class provides a character and line based interface to stream I/O.
+
+ There is no readinto() method, as character strings are immutable.
+ """
+
+ def read(self, n = -1):
+ """read(n: int = -1) -> unicode. Read at most n characters from stream.
+
+ Read from underlying buffer until we have n characters or we hit EOF.
+ If n is negative or omitted, read until EOF.
+ """
+ self._unsupported("read")
+
+ def write(self, s):
+ """write(s: unicode) -> int. Write string s to stream."""
+ self._unsupported("write")
+
+ def truncate(self, pos = None):
+ """truncate(pos: int = None) -> int. Truncate size to pos."""
+ self.flush()
+ if pos is None:
+ pos = self.tell()
+ self.seek(pos)
+ return self.buffer.truncate()
+
+ def readline(self):
+ """readline() -> unicode. Read until newline or EOF.
+
+ Returns an empty string if EOF is hit immediately.
+ """
+ self._unsupported("readline")
+
+ @property
+ def encoding(self):
+ """Subclasses should override."""
+ return None
+
+ @property
+ def newlines(self):
+ """newlines -> None | unicode | tuple of unicode. Line endings translated
+ so far.
+
+ Only line endings translated during reading are considered.
+
+ Subclasses should override.
+ """
+ return None
+
+
+class IncrementalNewlineDecoder(codecs.IncrementalDecoder):
+ """Codec used when reading a file in universal newlines mode.
+ It wraps another incremental decoder, translating \\r\\n and \\r into \\n.
+ It also records the types of newlines encountered.
+ When used with translate=False, it ensures that the newline sequence is
+ returned in one piece.
+ """
+ def __init__(self, decoder, translate, errors='strict'):
+ codecs.IncrementalDecoder.__init__(self, errors=errors)
+ self.buffer = b''
+ self.translate = translate
+ self.decoder = decoder
+ self.seennl = 0
+
+ def decode(self, input, final=False):
+ # decode input (with the eventual \r from a previous pass)
+ if self.buffer:
+ input = self.buffer + input
+
+ output = self.decoder.decode(input, final=final)
+
+ # retain last \r even when not translating data:
+ # then readline() is sure to get \r\n in one pass
+ if output.endswith("\r") and not final:
+ output = output[:-1]
+ self.buffer = b'\r'
+ else:
+ self.buffer = b''
+
+ # Record which newlines are read
+ crlf = output.count('\r\n')
+ cr = output.count('\r') - crlf
+ lf = output.count('\n') - crlf
+ self.seennl |= (lf and self._LF) | (cr and self._CR) \
+ | (crlf and self._CRLF)
+
+ if self.translate:
+ if crlf:
+ output = output.replace("\r\n", "\n")
+ if cr:
+ output = output.replace("\r", "\n")
+
+ return output
+
+ def getstate(self):
+ buf, flag = self.decoder.getstate()
+ return buf + self.buffer, flag
+
+ def setstate(self, state):
+ buf, flag = state
+ if buf.endswith(b'\r'):
+ self.buffer = b'\r'
+ buf = buf[:-1]
+ else:
+ self.buffer = b''
+ self.decoder.setstate((buf, flag))
+
+ def reset(self):
+ self.seennl = 0
+ self.buffer = b''
+ self.decoder.reset()
+
+ _LF = 1
+ _CR = 2
+ _CRLF = 4
+
+ @property
+ def newlines(self):
+ return (None,
+ "\n",
+ "\r",
+ ("\r", "\n"),
+ "\r\n",
+ ("\n", "\r\n"),
+ ("\r", "\r\n"),
+ ("\r", "\n", "\r\n")
+ )[self.seennl]
+
+
+class TextIOWrapper(TextIOBase):
+
+ """Buffered text stream.
+
+ Character and line based layer over a BufferedIOBase object.
+ """
+
+ _CHUNK_SIZE = 128
+
+ def __init__(self, buffer, encoding=None, errors=None, newline=None,
+ line_buffering=False):
+ if newline not in (None, "", "\n", "\r", "\r\n"):
+ raise ValueError("illegal newline value: %r" % (newline,))
+ if encoding is None:
+ try:
+ encoding = os.device_encoding(buffer.fileno())
+ except (AttributeError, UnsupportedOperation):
+ pass
+ if encoding is None:
+ try:
+ import locale
+ except ImportError:
+ # Importing locale may fail if Python is being built
+ encoding = "ascii"
+ else:
+ encoding = locale.getpreferredencoding()
+
+ if not isinstance(encoding, str):
+ raise ValueError("invalid encoding: %r" % encoding)
+
+ if errors is None:
+ errors = "strict"
+ else:
+ if not isinstance(errors, str):
+ raise ValueError("invalid errors: %r" % errors)
+
+ self.buffer = buffer
+ self._line_buffering = line_buffering
+ self._encoding = encoding
+ self._errors = errors
+ self._readuniversal = not newline
+ self._readtranslate = newline is None
+ self._readnl = newline
+ self._writetranslate = newline != ''
+ self._writenl = newline or os.linesep
+ self._encoder = None
+ self._decoder = None
+ self._decoded_chars = '' # buffer for text returned from decoder
+ self._decoded_chars_used = 0 # offset into _decoded_chars for read()
+ self._snapshot = None # info for reconstructing decoder state
+ self._seekable = self._telling = self.buffer.seekable()
+
+ # self._snapshot is either None, or a tuple (dec_flags, next_input)
+ # where dec_flags is the second (integer) item of the decoder state
+ # and next_input is the chunk of input bytes that comes next after the
+ # snapshot point. We use this to reconstruct decoder states in tell().
+
+ # Naming convention:
+ # - "bytes_..." for integer variables that count input bytes
+ # - "chars_..." for integer variables that count decoded characters
+
+ def __repr__(self):
+ return '<TIOW %x>' % id(self)
+
+ @property
+ def encoding(self):
+ return self._encoding
+
+ @property
+ def errors(self):
+ return self._errors
+
+ @property
+ def line_buffering(self):
+ return self._line_buffering
+
+ def seekable(self):
+ return self._seekable
+
+ def flush(self):
+ self.buffer.flush()
+ self._telling = self._seekable
+
+ def close(self):
+ try:
+ self.flush()
+ except:
+ pass # If flush() fails, just give up
+ self.buffer.close()
+
+ @property
+ def closed(self):
+ return self.buffer.closed
+
+ def fileno(self):
+ return self.buffer.fileno()
+
+ def isatty(self):
+ return self.buffer.isatty()
+
+ def write(self, s):
+ if self.closed:
+ raise ValueError("write to closed file")
+ if not isinstance(s, unicode):
+ raise TypeError("can't write %s to text stream" %
+ s.__class__.__name__)
+ length = len(s)
+ haslf = (self._writetranslate or self._line_buffering) and "\n" in s
+ if haslf and self._writetranslate and self._writenl != "\n":
+ s = s.replace("\n", self._writenl)
+ encoder = self._encoder or self._get_encoder()
+ # XXX What if we were just reading?
+ b = encoder.encode(s)
+ self.buffer.write(b)
+ if self._line_buffering and (haslf or "\r" in s):
+ self.flush()
+ self._snapshot = None
+ if self._decoder:
+ self._decoder.reset()
+ return length
+
+ def _get_encoder(self):
+ make_encoder = codecs.getincrementalencoder(self._encoding)
+ self._encoder = make_encoder(self._errors)
+ return self._encoder
+
+ def _get_decoder(self):
+ make_decoder = codecs.getincrementaldecoder(self._encoding)
+ decoder = make_decoder(self._errors)
+ if self._readuniversal:
+ decoder = IncrementalNewlineDecoder(decoder, self._readtranslate)
+ self._decoder = decoder
+ return decoder
+
+ # The following three methods implement an ADT for _decoded_chars.
+ # Text returned from the decoder is buffered here until the client
+ # requests it by calling our read() or readline() method.
+ def _set_decoded_chars(self, chars):
+ """Set the _decoded_chars buffer."""
+ self._decoded_chars = chars
+ self._decoded_chars_used = 0
+
+ def _get_decoded_chars(self, n=None):
+ """Advance into the _decoded_chars buffer."""
+ offset = self._decoded_chars_used
+ if n is None:
+ chars = self._decoded_chars[offset:]
+ else:
+ chars = self._decoded_chars[offset:offset + n]
+ self._decoded_chars_used += len(chars)
+ return chars
+
+ def _rewind_decoded_chars(self, n):
+ """Rewind the _decoded_chars buffer."""
+ if self._decoded_chars_used < n:
+ raise AssertionError("rewind decoded_chars out of bounds")
+ self._decoded_chars_used -= n
+
+ def _read_chunk(self):
+ """
+ Read and decode the next chunk of data from the BufferedReader.
+
+ The return value is True unless EOF was reached. The decoded string
+ is placed in self._decoded_chars (replacing its previous value).
+ The entire input chunk is sent to the decoder, though some of it
+ may remain buffered in the decoder, yet to be converted.
+ """
+
+ if self._decoder is None:
+ raise ValueError("no decoder")
+
+ if self._telling:
+ # To prepare for tell(), we need to snapshot a point in the
+ # file where the decoder's input buffer is empty.
+
+ dec_buffer, dec_flags = self._decoder.getstate()
+ # Given this, we know there was a valid snapshot point
+ # len(dec_buffer) bytes ago with decoder state (b'', dec_flags).
+
+ # Read a chunk, decode it, and put the result in self._decoded_chars.
+ input_chunk = self.buffer.read1(self._CHUNK_SIZE)
+ eof = not input_chunk
+ self._set_decoded_chars(self._decoder.decode(input_chunk, eof))
+
+ if self._telling:
+ # At the snapshot point, len(dec_buffer) bytes before the read,
+ # the next input to be decoded is dec_buffer + input_chunk.
+ self._snapshot = (dec_flags, dec_buffer + input_chunk)
+
+ return not eof
+
+ def _pack_cookie(self, position, dec_flags=0,
+ bytes_to_feed=0, need_eof=0, chars_to_skip=0):
+ # The meaning of a tell() cookie is: seek to position, set the
+ # decoder flags to dec_flags, read bytes_to_feed bytes, feed them
+ # into the decoder with need_eof as the EOF flag, then skip
+ # chars_to_skip characters of the decoded result. For most simple
+ # decoders, tell() will often just give a byte offset in the file.
+ return (position | (dec_flags<<64) | (bytes_to_feed<<128) |
+ (chars_to_skip<<192) | bool(need_eof)<<256)
+
+ def _unpack_cookie(self, bigint):
+ rest, position = divmod(bigint, 1<<64)
+ rest, dec_flags = divmod(rest, 1<<64)
+ rest, bytes_to_feed = divmod(rest, 1<<64)
+ need_eof, chars_to_skip = divmod(rest, 1<<64)
+ return position, dec_flags, bytes_to_feed, need_eof, chars_to_skip
+
+ def tell(self):
+ if not self._seekable:
+ raise IOError("underlying stream is not seekable")
+ if not self._telling:
+ raise IOError("telling position disabled by next() call")
+ self.flush()
+ position = self.buffer.tell()
+ decoder = self._decoder
+ if decoder is None or self._snapshot is None:
+ if self._decoded_chars:
+ # This should never happen.
+ raise AssertionError("pending decoded text")
+ return position
+
+ # Skip backward to the snapshot point (see _read_chunk).
+ dec_flags, next_input = self._snapshot
+ position -= len(next_input)
+
+ # How many decoded characters have been used up since the snapshot?
+ chars_to_skip = self._decoded_chars_used
+ if chars_to_skip == 0:
+ # We haven't moved from the snapshot point.
+ return self._pack_cookie(position, dec_flags)
+
+ # Starting from the snapshot position, we will walk the decoder
+ # forward until it gives us enough decoded characters.
+ saved_state = decoder.getstate()
+ try:
+ # Note our initial start point.
+ decoder.setstate((b'', dec_flags))
+ start_pos = position
+ start_flags, bytes_fed, chars_decoded = dec_flags, 0, 0
+ need_eof = 0
+
+ # Feed the decoder one byte at a time. As we go, note the
+ # nearest "safe start point" before the current location
+ # (a point where the decoder has nothing buffered, so seek()
+ # can safely start from there and advance to this location).
+ next_byte = bytearray(1)
+ for next_byte[0] in next_input:
+ bytes_fed += 1
+ chars_decoded += len(decoder.decode(next_byte))
+ dec_buffer, dec_flags = decoder.getstate()
+ if not dec_buffer and chars_decoded <= chars_to_skip:
+ # Decoder buffer is empty, so this is a safe start point.
+ start_pos += bytes_fed
+ chars_to_skip -= chars_decoded
+ start_flags, bytes_fed, chars_decoded = dec_flags, 0, 0
+ if chars_decoded >= chars_to_skip:
+ break
+ else:
+ # We didn't get enough decoded data; signal EOF to get more.
+ chars_decoded += len(decoder.decode(b'', final=True))
+ need_eof = 1
+ if chars_decoded < chars_to_skip:
+ raise IOError("can't reconstruct logical file position")
+
+ # The returned cookie corresponds to the last safe start point.
+ return self._pack_cookie(
+ start_pos, start_flags, bytes_fed, need_eof, chars_to_skip)
+ finally:
+ decoder.setstate(saved_state)
+
+ def seek(self, cookie, whence=0):
+ if not self._seekable:
+ raise IOError("underlying stream is not seekable")
+ if whence == 1: # seek relative to current position
+ if cookie != 0:
+ raise IOError("can't do nonzero cur-relative seeks")
+ # Seeking to the current position should attempt to
+ # sync the underlying buffer with the current position.
+ whence = 0
+ cookie = self.tell()
+ if whence == 2: # seek relative to end of file
+ if cookie != 0:
+ raise IOError("can't do nonzero end-relative seeks")
+ self.flush()
+ position = self.buffer.seek(0, 2)
+ self._set_decoded_chars('')
+ self._snapshot = None
+ if self._decoder:
+ self._decoder.reset()
+ return position
+ if whence != 0:
+ raise ValueError("invalid whence (%r, should be 0, 1 or 2)" %
+ (whence,))
+ if cookie < 0:
+ raise ValueError("negative seek position %r" % (cookie,))
+ self.flush()
+
+ # The strategy of seek() is to go back to the safe start point
+ # and replay the effect of read(chars_to_skip) from there.
+ start_pos, dec_flags, bytes_to_feed, need_eof, chars_to_skip = \
+ self._unpack_cookie(cookie)
+
+ # Seek back to the safe start point.
+ self.buffer.seek(start_pos)
+ self._set_decoded_chars('')
+ self._snapshot = None
+
+ # Restore the decoder to its state from the safe start point.
+ if self._decoder or dec_flags or chars_to_skip:
+ self._decoder = self._decoder or self._get_decoder()
+ self._decoder.setstate((b'', dec_flags))
+ self._snapshot = (dec_flags, b'')
+
+ if chars_to_skip:
+ # Just like _read_chunk, feed the decoder and save a snapshot.
+ input_chunk = self.buffer.read(bytes_to_feed)
+ self._set_decoded_chars(
+ self._decoder.decode(input_chunk, need_eof))
+ self._snapshot = (dec_flags, input_chunk)
+
+ # Skip chars_to_skip of the decoded characters.
+ if len(self._decoded_chars) < chars_to_skip:
+ raise IOError("can't restore logical file position")
+ self._decoded_chars_used = chars_to_skip
+
+ return cookie
+
+ def read(self, n=None):
+ if n is None:
+ n = -1
+ decoder = self._decoder or self._get_decoder()
+ if n < 0:
+ # Read everything.
+ result = (self._get_decoded_chars() +
+ decoder.decode(self.buffer.read(), final=True))
+ self._set_decoded_chars('')
+ self._snapshot = None
+ return result
+ else:
+ # Keep reading chunks until we have n characters to return.
+ eof = False
+ result = self._get_decoded_chars(n)
+ while len(result) < n and not eof:
+ eof = not self._read_chunk()
+ result += self._get_decoded_chars(n - len(result))
+ return result
+
+ def next(self):
+ self._telling = False
+ line = self.readline()
+ if not line:
+ self._snapshot = None
+ self._telling = self._seekable
+ raise StopIteration
+ return line
+
+ def readline(self, limit=None):
+ if limit is None:
+ limit = -1
+
+ # Grab all the decoded text (we will rewind any extra bits later).
+ line = self._get_decoded_chars()
+
+ start = 0
+ decoder = self._decoder or self._get_decoder()
+
+ pos = endpos = None
+ while True:
+ if self._readtranslate:
+ # Newlines are already translated, only search for \n
+ pos = line.find('\n', start)
+ if pos >= 0:
+ endpos = pos + 1
+ break
+ else:
+ start = len(line)
+
+ elif self._readuniversal:
+ # Universal newline search. Find any of \r, \r\n, \n
+ # The decoder ensures that \r\n are not split in two pieces
+
+ # In C we'd look for these in parallel of course.
+ nlpos = line.find("\n", start)
+ crpos = line.find("\r", start)
+ if crpos == -1:
+ if nlpos == -1:
+ # Nothing found
+ start = len(line)
+ else:
+ # Found \n
+ endpos = nlpos + 1
+ break
+ elif nlpos == -1:
+ # Found lone \r
+ endpos = crpos + 1
+ break
+ elif nlpos < crpos:
+ # Found \n
+ endpos = nlpos + 1
+ break
+ elif nlpos == crpos + 1:
+ # Found \r\n
+ endpos = crpos + 2
+ break
+ else:
+ # Found \r
+ endpos = crpos + 1
+ break
+ else:
+ # non-universal
+ pos = line.find(self._readnl)
+ if pos >= 0:
+ endpos = pos + len(self._readnl)
+ break
+
+ if limit >= 0 and len(line) >= limit:
+ endpos = limit # reached length limit
+ break
+
+ # No line ending seen yet - get more data
+ more_line = ''
+ while self._read_chunk():
+ if self._decoded_chars:
+ break
+ if self._decoded_chars:
+ line += self._get_decoded_chars()
+ else:
+ # end of file
+ self._set_decoded_chars('')
+ self._snapshot = None
+ return line
+
+ if limit >= 0 and endpos > limit:
+ endpos = limit # don't exceed limit
+
+ # Rewind _decoded_chars to just after the line ending we found.
+ self._rewind_decoded_chars(len(line) - endpos)
+ return line[:endpos]
+
+ @property
+ def newlines(self):
+ return self._decoder.newlines if self._decoder else None
+
+class StringIO(TextIOWrapper):
+
+ # XXX This is really slow, but fully functional
+
+ def __init__(self, initial_value="", encoding="utf-8",
+ errors="strict", newline="\n"):
+ super(StringIO, self).__init__(BytesIO(),
+ encoding=encoding,
+ errors=errors,
+ newline=newline)
+ if initial_value:
+ if not isinstance(initial_value, unicode):
+ initial_value = unicode(initial_value)
+ self.write(initial_value)
+ self.seek(0)
+
+ def getvalue(self):
+ self.flush()
+ return self.buffer.getvalue().decode(self._encoding, self._errors)