Change summary:
+ There is now a `gzip.READ_BUFFER_SIZE` constant that is 128KB. Other programs that read in 128KB chunks: pigz and cat. So this seems best practice among good programs. Also it is faster than 8 kb chunks.
+ a zlib._ZlibDecompressor was added. This is the _bz2.BZ2Decompressor ported to zlib. Since the zlib.Decompress object is better for in-memory decompression, the _ZlibDecompressor is hidden. It only makes sense in file decompression, and that is already implemented now in the gzip library. No need to bother the users with this.
+ The ZlibDecompressor uses the older Cpython arrange_output_buffer functions, as those are faster and more appropriate for the use case.
+ GzipFile.read has been optimized. There is no longer a `unconsumed_tail` member to write back to padded file. This is instead handled by the ZlibDecompressor itself, which has an internal buffer. `_add_read_data` has been inlined, as it was just two calls.
EDIT: While I am adding improvements anyway, I figured I could add another one-liner optimization now to the python -m gzip application. That read chunks in io.DEFAULT_BUFFER_SIZE previously, but has been updated now to use READ_BUFFER_SIZE chunks.
We only statically initialize for core code and builtin modules. Extension modules still create
the tuple at runtime. We'll solve that part of interpreter isolation separately.
This change includes generated code. The non-generated changes are in:
* Tools/clinic/clinic.py
* Python/getargs.c
* Include/cpython/modsupport.h
* Makefile.pre.in (re-generate global strings after running clinic)
* very minor tweaks to Modules/_codecsmodule.c and Python/Python-tokenize.c
All other changes are generated code (clinic, global strings).
When compiled with `USE_ZLIB_CRC32` defined (`configure` sets this on POSIX systems), `binascii.crc32(...)` failed to compute the correct value when the input data was >= 4GiB. Because the zlib crc32 API is limited to a 32-bit length.
This lines it up with the `zlib.crc32(...)` implementation that doesn't have that flaw.
**Performance:** This also adopts the same GIL releasing for larger inputs logic that `zlib.crc32` has, and causes the Windows build to always use zlib's crc32 instead of our slow C code as zlib is a required build dependency on Windows.
Previously, the result could have been an instance of a subclass of int.
Also revert bpo-26202 and make attributes start, stop and step of the range
object having exact type int.
Add private function _PyNumber_Index() which preserves the old behavior
of PyNumber_Index() for performance to use it in the conversion functions
like PyLong_AsLong().
Fix invalid function cast warnings with gcc 8
for method conventions different from METH_NOARGS, METH_O and
METH_VARARGS in Argument Clinic generated code.
When a single .c file contains several functions and/or methods with
the same name, a safety _METHODDEF #define statement is generated
only for one of them.
This fixes the bug by using the full name of the function to avoid
duplicates rather than just the name.
The function '_PyArg_ParseStack()' and
'_PyArg_UnpackStack' were failing (with error
"XXX() takes Y argument (Z given)") before
the function '_PyArg_NoStackKeywords()' was called.
Thus, the latter did not raise its more meaningful
error : "XXX() takes no keyword arguments".
The underlying zlib library stores sizes in “unsigned int”. The corresponding
Python parameters are all sizes of buffers filled in by zlib, so it is okay
to reduce higher values to the UINT_MAX internal cap. OverflowError is still
raised for sizes that do not fit in Py_ssize_t.
Sizes are now limited to Py_ssize_t rather than unsigned long, because Python
byte strings cannot be larger than Py_ssize_t. Previously this could result
in a SystemError on 32-bit platforms.
This resolves a regression in the gzip module when reading more than UINT_MAX
or LONG_MAX bytes in one call, introduced by revision 62723172412c.
(empty) definition of the methoddef macro: it's only generated once, even
if Argument Clinic processes the same symbol multiple times, and it's emitted
at the end of all processing rather than immediately after the first use.
The new syntax is highly human readable while still preventing false
positives. The syntax also extends Python syntax to denote "self" and
positional-only parameters, allowing inspect.Signature objects to be
totally accurate for all supported builtins in Python 3.4.
annotate text signatures in docstrings, resulting in fewer false
positives. "self" parameters are also explicitly marked, allowing
inspect.Signature() to authoritatively detect (and skip) said parameters.
Issue #20326: Argument Clinic now generates separate checksums for the
input and output sections of the block, allowing external tools to verify
that the input has not changed (and thus the output is not out-of-date).
Victor Stinner
Ruben Vorderman
Erlend E. Aasland
Eric Snow
Serhiy Storchaka
Gregory P. Smith
Mohamed Koubaa
Rémi Lapeyre
Zackery Spytz
Tal Einat
Sylvain
Victor Stinner
Martin Panter
Larry Hastings