Issue #15677: Document that zlib and gzip accept a compression level of 0 to mean 'no compression'.
Patch by Brian Brazil.
diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst
index 50d0462..2cbd2d5 100644
--- a/Doc/library/gzip.rst
+++ b/Doc/library/gzip.rst
@@ -38,7 +38,7 @@
``'w'``, or ``'wb'`` for binary mode, or ``'rt'``, ``'at'``, or ``'wt'`` for
text mode. The default is ``'rb'``.
- The *compresslevel* argument is an integer from 1 to 9, as for the
+ The *compresslevel* argument is an integer from 0 to 9, as for the
:class:`GzipFile` constructor.
For binary mode, this function is equivalent to the :class:`GzipFile`
@@ -80,9 +80,10 @@
in text mode, use :func:`.open` (or wrap your :class:`GzipFile` with an
:class:`io.TextIOWrapper`).
- 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``.
+ The *compresslevel* argument is an integer from ``0`` to ``9`` controlling
+ the level of compression; ``1`` is fastest and produces the least
+ compression, and ``9`` is slowest and produces the most compression. ``0``
+ is no compression. The default is ``9``.
The *mtime* argument is an optional numeric timestamp to be written to
the stream when compressing. All :program:`gzip` compressed streams are
diff --git a/Doc/library/zlib.rst b/Doc/library/zlib.rst
index 42535a0..731023e 100644
--- a/Doc/library/zlib.rst
+++ b/Doc/library/zlib.rst
@@ -52,10 +52,10 @@
.. function:: compress(data[, level])
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;
+ *level* is an integer from ``0`` 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`
- exception if any error occurs.
+ produces the most. ``0`` is no compression. The default value is ``6``.
+ Raises the :exc:`error` exception if any error occurs.
.. function:: compressobj(level=-1, method=DEFLATED, wbits=15, memlevel=8, strategy=Z_DEFAULT_STRATEGY[, zdict])
@@ -63,9 +63,10 @@
Returns a compression object, to be used for compressing data streams that won't
fit into memory at once.
- *level* is the compression level -- an integer from ``1`` to ``9``. A value
+ *level* is the compression level -- an integer from ``0`` to ``9``. A value
of ``1`` is fastest and produces the least compression, while a value of
- ``9`` is slowest and produces the most. The default value is ``6``.
+ ``9`` is slowest and produces the most. ``0`` is no compression. The default
+ value is ``6``.
*method* is the compression algorithm. Currently, the only supported value is
``DEFLATED``.