diff --git a/Doc/library/zlib.rst b/Doc/library/zlib.rst index 3d742ab35b9..8a531c92b8f 100644 --- a/Doc/library/zlib.rst +++ b/Doc/library/zlib.rst @@ -51,9 +51,9 @@ The available exception and functions in this module are: Compresses the bytes in *data*, returning a bytes object containing compressed data. *level* is an integer from ``0`` to ``9`` or ``-1`` 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 ``-1`` - (Z_DEFAULT_COMPRESSION). Z_DEFAULT_COMPRESSION represents a default + ``1`` (Z_BEST_SPEED) is fastest and produces the least compression, ``9`` (Z_BEST_COMPRESSION) + is slowest and produces the most. ``0`` (Z_NO_COMPRESSION) is no compression. + The default value is ``-1`` (Z_DEFAULT_COMPRESSION). Z_DEFAULT_COMPRESSION represents a default compromise between speed and compression (currently equivalent to level 6). Raises the :exc:`error` exception if any error occurs. @@ -61,23 +61,25 @@ The available exception and functions in this module are: *level* can now be used as a keyword parameter. -.. function:: compressobj(level=-1, method=DEFLATED, wbits=15, memLevel=8, strategy=Z_DEFAULT_STRATEGY[, zdict]) +.. function:: compressobj(level=-1, method=DEFLATED, wbits=MAX_WBITS, memLevel=DEF_MEM_LEVEL, strategy=Z_DEFAULT_STRATEGY[, zdict]) 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 ``0`` to ``9`` or ``-1``. - A value of ``1`` is fastest and produces the least compression, while a value of - ``9`` is slowest and produces the most. ``0`` is no compression. The default - value is ``-1`` (Z_DEFAULT_COMPRESSION). Z_DEFAULT_COMPRESSION represents a default - compromise between speed and compression (currently equivalent to level 6). + A value of ``1`` (Z_BEST_SPEED) is fastest and produces the least compression, + while a value of ``9`` (Z_BEST_COMPRESSION) is slowest and produces the most. + ``0`` (Z_NO_COMPRESSION) is no compression. The default value is ``-1`` (Z_DEFAULT_COMPRESSION). + Z_DEFAULT_COMPRESSION represents a default compromise between speed and compression + (currently equivalent to level 6). *method* is the compression algorithm. Currently, the only supported value is - ``DEFLATED``. + :const:`DEFLATED`. The *wbits* argument controls the size of the history buffer (or the "window size") used when compressing data, and whether a header and - trailer is included in the output. It can take several ranges of values: + trailer is included in the output. It can take several ranges of values, + defaulting to ``15`` (MAX_WBITS): * +9 to +15: The base-two logarithm of the window size, which therefore ranges between 512 and 32768. Larger values produce @@ -97,7 +99,8 @@ The available exception and functions in this module are: Higher values use more memory, but are faster and produce smaller output. *strategy* is used to tune the compression algorithm. Possible values are - ``Z_DEFAULT_STRATEGY``, ``Z_FILTERED``, and ``Z_HUFFMAN_ONLY``. + :const:`Z_DEFAULT_STRATEGY`, :const:`Z_FILTERED`, :const:`Z_HUFFMAN_ONLY`, + :const:`Z_RLE` (zlib 1.2.0.1) and :const:`Z_FIXED` (zlib 1.2.2.2). *zdict* is a predefined compression dictionary. This is a sequence of bytes (such as a :class:`bytes` object) containing subsequences that are expected @@ -175,7 +178,7 @@ The available exception and functions in this module are: .. versionchanged:: 3.6 *wbits* and *bufsize* can be used as keyword arguments. -.. function:: decompressobj(wbits=15[, zdict]) +.. function:: decompressobj(wbits=MAX_WBITS[, zdict]) Returns a decompression object, to be used for decompressing data streams that won't fit into memory at once. @@ -213,13 +216,13 @@ Compression objects support the following methods: 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 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 - to delete the object. + :const:`Z_NO_FLUSH`, :const:`Z_PARTIAL_FLUSH`, :const:`Z_SYNC_FLUSH`, + :const:`Z_FULL_FLUSH`, :const:`Z_BLOCK` (zlib 1.2.3.4), or :const:`Z_FINISH`, + defaulting to :const:`Z_FINISH`. Except :const:`Z_FINISH`, all constants + 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 to delete the object. .. method:: Compress.copy() diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py index db950fc1907..99aa89bdc8c 100644 --- a/Lib/test/test_zlib.py +++ b/Lib/test/test_zlib.py @@ -434,7 +434,8 @@ class CompressObjectTestCase(BaseCompressTestCase, unittest.TestCase): def test_flushes(self): # Test flush() with the various options, using all the # different levels in order to provide more variations. - sync_opt = ['Z_NO_FLUSH', 'Z_SYNC_FLUSH', 'Z_FULL_FLUSH'] + sync_opt = ['Z_NO_FLUSH', 'Z_SYNC_FLUSH', 'Z_FULL_FLUSH', + 'Z_PARTIAL_FLUSH', 'Z_BLOCK'] sync_opt = [getattr(zlib, opt) for opt in sync_opt if hasattr(zlib, opt)] data = HAMLET_SCENE * 8 diff --git a/Misc/NEWS.d/next/Library/2018-03-06-00-19-41.bpo-32969.rGTKa0.rst b/Misc/NEWS.d/next/Library/2018-03-06-00-19-41.bpo-32969.rGTKa0.rst new file mode 100644 index 00000000000..a92307e67bf --- /dev/null +++ b/Misc/NEWS.d/next/Library/2018-03-06-00-19-41.bpo-32969.rGTKa0.rst @@ -0,0 +1,2 @@ +Expose several missing constants in zlib and fix corresponding +documentation. diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c index cb2aae10694..cd587b4ac9c 100644 --- a/Modules/zlibmodule.c +++ b/Modules/zlibmodule.c @@ -1361,18 +1361,33 @@ PyInit_zlib(void) PyModule_AddIntMacro(m, DEFLATED); PyModule_AddIntMacro(m, DEF_MEM_LEVEL); PyModule_AddIntMacro(m, DEF_BUF_SIZE); + // compression levels + PyModule_AddIntMacro(m, Z_NO_COMPRESSION); PyModule_AddIntMacro(m, Z_BEST_SPEED); PyModule_AddIntMacro(m, Z_BEST_COMPRESSION); PyModule_AddIntMacro(m, Z_DEFAULT_COMPRESSION); + // compression strategies PyModule_AddIntMacro(m, Z_FILTERED); PyModule_AddIntMacro(m, Z_HUFFMAN_ONLY); +#ifdef Z_RLE // 1.2.0.1 + PyModule_AddIntMacro(m, Z_RLE); +#endif +#ifdef Z_FIXED // 1.2.2.2 + PyModule_AddIntMacro(m, Z_FIXED); +#endif PyModule_AddIntMacro(m, Z_DEFAULT_STRATEGY); - - PyModule_AddIntMacro(m, Z_FINISH); + // allowed flush values PyModule_AddIntMacro(m, Z_NO_FLUSH); + PyModule_AddIntMacro(m, Z_PARTIAL_FLUSH); PyModule_AddIntMacro(m, Z_SYNC_FLUSH); PyModule_AddIntMacro(m, Z_FULL_FLUSH); - + PyModule_AddIntMacro(m, Z_FINISH); +#ifdef Z_BLOCK // 1.2.0.5 for inflate, 1.2.3.4 for deflate + PyModule_AddIntMacro(m, Z_BLOCK); +#endif +#ifdef Z_TREES // 1.2.3.4, only for inflate + PyModule_AddIntMacro(m, Z_TREES); +#endif ver = PyUnicode_FromString(ZLIB_VERSION); if (ver != NULL) PyModule_AddObject(m, "ZLIB_VERSION", ver);