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+:mod:`gzip` --- Support for :program:`gzip` files
+=================================================
+
+.. module:: gzip
+ :synopsis: Interfaces for gzip compression and decompression using file objects.
+
+
+The data compression provided by the ``zlib`` module is compatible with that
+used by the GNU compression program :program:`gzip`. Accordingly, the
+:mod:`gzip` module provides the :class:`GzipFile` class to read and write
+:program:`gzip`\ -format files, automatically compressing or decompressing the
+data so it looks like an ordinary file object. Note that additional file
+formats which can be decompressed by the :program:`gzip` and :program:`gunzip`
+programs, such as those produced by :program:`compress` and :program:`pack`,
+are not supported by this module.
+
+The module defines the following items:
+
+
+.. class:: GzipFile([filename[, mode[, compresslevel[, fileobj]]]])
+
+ Constructor for the :class:`GzipFile` class, which simulates most of the methods
+ of a file object, with the exception of the :meth:`readinto` and
+ :meth:`truncate` methods. At least one of *fileobj* and *filename* must be
+ given a non-trivial value.
+
+ The new class instance is based on *fileobj*, which can be a regular file, a
+ :class:`StringIO` object, or any other object which simulates a file. It
+ defaults to ``None``, in which case *filename* is opened to provide a file
+ object.
+
+ When *fileobj* is not ``None``, the *filename* argument is only used to be
+ included in the :program:`gzip` file header, which may includes the original
+ filename of the uncompressed file. It defaults to the filename of *fileobj*, if
+ discernible; otherwise, it defaults to the empty string, and in this case the
+ original filename is not included in the header.
+
+ The *mode* argument can be any of ``'r'``, ``'rb'``, ``'a'``, ``'ab'``, ``'w'``,
+ or ``'wb'``, depending on whether the file will be read or written. The default
+ is the mode of *fileobj* if discernible; otherwise, the default is ``'rb'``. If
+ not given, the 'b' flag will be added to the mode to ensure the file is opened
+ in binary mode for cross-platform portability.
+
+ The *compresslevel* argument is an integer from ``1`` to ``9`` controlling the
+ level of compression; ``1`` is fastest and produces the least compression, and
+ ``9`` is slowest and produces the most compression. The default is ``9``.
+
+ Calling a :class:`GzipFile` object's :meth:`close` method does not close
+ *fileobj*, since you might wish to append more material after the compressed
+ data. This also allows you to pass a :class:`StringIO` object opened for
+ writing as *fileobj*, and retrieve the resulting memory buffer using the
+ :class:`StringIO` object's :meth:`getvalue` method.
+
+
+.. function:: open(filename[, mode[, compresslevel]])
+
+ This is a shorthand for ``GzipFile(filename,`` ``mode,`` ``compresslevel)``.
+ The *filename* argument is required; *mode* defaults to ``'rb'`` and
+ *compresslevel* defaults to ``9``.
+
+
+.. seealso::
+
+ Module :mod:`zlib`
+ The basic data compression module needed to support the :program:`gzip` file
+ format.
+