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zlib only works with bytes objects.

This commit is contained in:
Georg Brandl 2011-01-08 21:04:25 +00:00
parent 2997837158
commit 4ad934f63c
1 changed files with 22 additions and 22 deletions
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Doc/library/zlib.rst
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@ -51,9 +51,9 @@ The available exception and functions in this module are:
regardless of sign.
.. function:: compress(string[, level])
.. function:: compress(data[, level])
Compresses the data in *string*, returning a string contained compressed data.
Compresses the bytes in *data*, returning a bytes object containing compressed data.
*level* is an integer from ``1`` to ``9`` controlling the level of compression;
``1`` is fastest and produces the least compression, ``9`` is slowest and
produces the most. The default value is ``6``. Raises the :exc:`error`
@ -92,9 +92,9 @@ The available exception and functions in this module are:
regardless of sign.
.. function:: decompress(string[, wbits[, bufsize]])
.. function:: decompress(data[, wbits[, bufsize]])
Decompresses the data in *string*, returning a string containing the
Decompresses the bytes in *data*, returning a bytes object containing the
uncompressed data. The *wbits* parameter controls the size of the window
buffer, and is discussed further below.
If *bufsize* is given, it is used as the initial size of the output
@ -125,21 +125,21 @@ The available exception and functions in this module are:
Compression objects support the following methods:
.. method:: Compress.compress(string)
.. method:: Compress.compress(data)
Compress *string*, returning a string containing compressed data for at least
part of the data in *string*. This data should be concatenated to the output
Compress *data*, returning a bytes object containing compressed data for at least
part of the data in *data*. This data should be concatenated to the output
produced by any preceding calls to the :meth:`compress` method. Some input may
be kept in internal buffers for later processing.
.. method:: Compress.flush([mode])
All pending input is processed, and a string containing the remaining compressed
All pending input is processed, and a bytes object containing the remaining compressed
output is returned. *mode* can be selected from the constants
:const:`Z_SYNC_FLUSH`, :const:`Z_FULL_FLUSH`, or :const:`Z_FINISH`,
defaulting to :const:`Z_FINISH`. :const:`Z_SYNC_FLUSH` and
:const:`Z_FULL_FLUSH` allow compressing further strings of data, while
:const:`Z_FULL_FLUSH` allow compressing further bytestrings of data, while
:const:`Z_FINISH` finishes the compressed stream and prevents compressing any
more data. After calling :meth:`flush` with *mode* set to :const:`Z_FINISH`,
the :meth:`compress` method cannot be called again; the only realistic action is
@ -157,31 +157,31 @@ Decompression objects support the following methods, and two attributes:
.. attribute:: Decompress.unused_data
A string which contains any bytes past the end of the compressed data. That is,
A bytes object which contains any bytes past the end of the compressed data. That is,
this remains ``""`` until the last byte that contains compression data is
available. If the whole string turned out to contain compressed data, this is
``""``, the empty string.
available. If the whole bytestring turned out to contain compressed data, this is
``b""``, an empty bytes object.
The only way to determine where a string of compressed data ends is by actually
The only way to determine where a bytestring of compressed data ends is by actually
decompressing it. This means that when compressed data is contained part of a
larger file, you can only find the end of it by reading data and feeding it
followed by some non-empty string into a decompression object's
followed by some non-empty bytestring into a decompression object's
:meth:`decompress` method until the :attr:`unused_data` attribute is no longer
the empty string.
empty.
.. attribute:: Decompress.unconsumed_tail
A string that contains any data that was not consumed by the last
A bytes object that contains any data that was not consumed by the last
:meth:`decompress` call because it exceeded the limit for the uncompressed data
buffer. This data has not yet been seen by the zlib machinery, so you must feed
it (possibly with further data concatenated to it) back to a subsequent
:meth:`decompress` method call in order to get correct output.
.. method:: Decompress.decompress(string[, max_length])
.. method:: Decompress.decompress(data[, max_length])
Decompress *string*, returning a string containing the uncompressed data
Decompress *data*, returning a bytes object containing the uncompressed data
corresponding to at least part of the data in *string*. This data should be
concatenated to the output produced by any preceding calls to the
:meth:`decompress` method. Some of the input data may be preserved in internal
@ -190,15 +190,15 @@ Decompression objects support the following methods, and two attributes:
If the optional parameter *max_length* is supplied then the return value will be
no longer than *max_length*. This may mean that not all of the compressed input
can be processed; and unconsumed data will be stored in the attribute
:attr:`unconsumed_tail`. This string must be passed to a subsequent call to
:attr:`unconsumed_tail`. This bytestring must be passed to a subsequent call to
:meth:`decompress` if decompression is to continue. If *max_length* is not
supplied then the whole input is decompressed, and :attr:`unconsumed_tail` is an
empty string.
supplied then the whole input is decompressed, and :attr:`unconsumed_tail` is
empty.
.. method:: Decompress.flush([length])
All pending input is processed, and a string containing the remaining
All pending input is processed, and a bytes object containing the remaining
uncompressed output is returned. After calling :meth:`flush`, the
:meth:`decompress` method cannot be called again; the only realistic action is
to delete the object.