[Python-checkins] cpython (3.2): Issue #15677: Document that zlib and gzip accept a compression level of 0 to

Sun Nov 11 14:20:38 CET 2012

http://hg.python.org/cpython/rev/9dde30690f44
changeset: 80386:9dde30690f44
branch: 3.2
parent: 80379:6ebfdfe74c04
user: Nadeem Vawda <nadeem.vawda at gmail.com>
date: Sun Nov 11 14:04:14 2012 +0100
summary:
 Issue #15677: Document that zlib and gzip accept a compression level of 0 to mean 'no compression'.
Patch by Brian Brazil.
files:
 Doc/library/gzip.rst | 7 ++++---
 Doc/library/zlib.rst | 15 ++++++++-------
 Lib/gzip.py | 7 ++++---
 Misc/NEWS | 3 +++
 Modules/zlibmodule.c | 6 +++---
 5 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst
--- a/Doc/library/gzip.rst
+++ b/Doc/library/gzip.rst
@@ -50,9 +50,10 @@
 supported. If you need to read a compressed file in text mode, 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
--- a/Doc/library/zlib.rst
+++ b/Doc/library/zlib.rst
@@ -51,19 +51,20 @@
 
 .. 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;
- ``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.
+ Compresses the bytes in *data*, returning a bytes object containing
+ compressed data. *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. ``0`` is no compression. The default
+ value is ``6``. Raises the :exc:`error` exception if any error occurs.
 
 
 .. function:: compressobj([level])
 
 Returns a compression object, to be used for compressing data streams that won't
- fit into memory at once. *level* is an integer from ``1`` to ``9`` controlling
+ fit into memory at once. *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``.
+ ``9`` is slowest and produces the most. ``0`` is no compression. The default
+ value is ``6``.
 
 
 .. function:: crc32(data[, value])
diff --git a/Lib/gzip.py b/Lib/gzip.py
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -137,9 +137,10 @@
 A mode of 'r' is equivalent to one of 'rb', and similarly for 'w' and
 'wb', and 'a' and 'ab'.
 
- The compresslevel argument is an integer from 1 to 9 controlling the
+ 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. The default is 9.
+ and 9 is slowest and produces the most compression. 0 is no compression
+ at all. The default is 9.
 
 The mtime argument is an optional numeric timestamp to be written
 to the stream when compressing. All gzip compressed streams
@@ -573,7 +574,7 @@
 
 def compress(data, compresslevel=9):
 """Compress data in one shot and return the compressed string.
- Optional argument is the compression level, in range of 1-9.
+ Optional argument is the compression level, in range of 0-9.
 """
 buf = io.BytesIO()
 with GzipFile(fileobj=buf, mode='wb', compresslevel=compresslevel) as f:
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -714,6 +714,9 @@
 Documentation
 -------------
 
+- Issue #15677: Document that zlib and gzip accept a compression level of 0 to
+ mean 'no compression'. Patch by Brian Brazil.
+
 - Issue #8040: added a version switcher to the documentation. Patch by
 Yury Selivanov.
 
diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -81,7 +81,7 @@
 PyDoc_STRVAR(compressobj__doc__,
 "compressobj([level]) -- Return a compressor object.\n"
 "\n"
-"Optional arg level is the compression level, in 1-9.");
+"Optional arg level is the compression level, in 0-9.");
 
 PyDoc_STRVAR(decompressobj__doc__,
 "decompressobj([wbits]) -- Return a decompressor object.\n"
@@ -115,7 +115,7 @@
 PyDoc_STRVAR(compress__doc__,
 "compress(string[, level]) -- Returned compressed string.\n"
 "\n"
-"Optional arg level is the compression level, in 1-9.");
+"Optional arg level is the compression level, in 0-9.");
 
 static PyObject *
 PyZlib_compress(PyObject *self, PyObject *args)
@@ -1135,7 +1135,7 @@
 "zlib library, which is based on GNU zip.\n"
 "\n"
 "adler32(string[, start]) -- Compute an Adler-32 checksum.\n"
-"compress(string[, level]) -- Compress string, with compression level in 1-9.\n"
+"compress(string[, level]) -- Compress string, with compression level in 0-9.\n"
 "compressobj([level]) -- Return a compressor object.\n"
 "crc32(string[, start]) -- Compute a CRC-32 checksum.\n"
 "decompress(string,[wbits],[bufsize]) -- Decompresses a compressed string.\n"
-- 
Repository URL: http://hg.python.org/cpython
