Factorize code to convert int/float to time_t, timeval or timespec

[vstinner]

BPO	14180
Nosy	@birkenfeld, @gpshead, @abalkin, @vstinner
Files	pytime.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2012-03-13.12:38:43.420>
created_at = <Date 2012-03-03.00:10:21.634>
labels = ['library']
title = 'Factorize code to convert int/float to time_t, timeval or timespec'
updated_at = <Date 2012-03-13.23:20:38.655>
user = 'https://github.com/vstinner'

bugs.python.org fields:

activity = <Date 2012-03-13.23:20:38.655>
actor = 'python-dev'
assignee = 'none'
closed = True
closed_date = <Date 2012-03-13.12:38:43.420>
closer = 'python-dev'
components = ['Library (Lib)']
creation = <Date 2012-03-03.00:10:21.634>
creator = 'vstinner'
dependencies = []
files = ['24716']
hgrepos = []
issue_num = 14180
keywords = ['patch']
message_count = 9.0
messages = ['154811', '154984', '155600', '155601', '155616', '155625', '155631', '155639', '155689']
nosy_count = 5.0
nosy_names = ['georg.brandl', 'gregory.p.smith', 'belopolsky', 'vstinner', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue14180'
versions = ['Python 3.3']

[vstinner]

There are various ways to convert a Python int/float to a C time_t, timeval or timespec structure. Attached patch factorize code by adding functions to convert a Python object to a C type (time_t, timeval or timespec).

My patch changes how datetime rounds microsecond: round towards zero instead of rounding to nearest with ties going away from zero. I chose this rounding method because it is the method used by int(float) and int(time.time()) is a common in programs (more than round(time.time()). Rounding towards zero avoids also producing timestamps in the future.

On overflow, an OverflowError is now raises instead of a ValueError. I prefer OverflowError over ValueError because it is an implementation detail. For example, time_t is 32 bits on Linux 32 bits, 64 bits on Linux 64 bits or on Windows (32 or 64 bits).

PyTime_ObjectToXXX() functions are part of Python and so can be used by the posix, time, datetime and select modules. The patch removes _time.c, _time.h and timefunc.h because these files were only used for one function (_PyTime_DoubleToTime_t) which is no more used and it required to link a module to _time.c to get this function.

--

If it is a problem to replace ValueError with OverflowError for backward compatibility, it is easy to adapt the patch to raise ValueError instead.

timedelta*float and timedelta/float rounding method may also be changed.

[vstinner]

Alexander: No complain if I remove _time.c?

[python-dev]

New changeset 1e9cc1a03365 by Victor Stinner in branch 'default':
Close bpo-14180: Factorize code to convert a number of seconds to time_t, timeval or timespec
http://hg.python.org/cpython/rev/1e9cc1a03365

[python-dev]

New changeset ed73006bac42 by Victor Stinner in branch 'default':
Issue bpo-14180: Remove commented code
http://hg.python.org/cpython/rev/ed73006bac42

[python-dev]

New changeset 1eaf6e899f02 by Victor Stinner in branch 'default':
Issue bpo-14180: Fix select.select() compilation on BSD and a typo in kqueue_queue_control()
http://hg.python.org/cpython/rev/1eaf6e899f02

[python-dev]

New changeset cb1c877a27f2 by Victor Stinner in branch 'default':
Issue bpo-14180: Fix another typo in kqueue_queue_control()
http://hg.python.org/cpython/rev/cb1c877a27f2

[python-dev]

New changeset 760cf150bb99 by Victor Stinner in branch 'default':
Issue bpo-14180: Fix pythoncore.vcproj, Modules/_time.[ch] have been removed
http://hg.python.org/cpython/rev/760cf150bb99

[python-dev]

New changeset 9d69a2418d80 by Victor Stinner in branch 'default':
Issue bpo-14180: Fix an invalid rounding when compiler optimization are enabled
http://hg.python.org/cpython/rev/9d69a2418d80

[python-dev]

New changeset 5d6a5c5a4ebe by Victor Stinner in branch 'default':
Issue bpo-14180: datetime.date.fromtimestamp(), datetime.datetime.fromtimestamp()
http://hg.python.org/cpython/rev/5d6a5c5a4ebe

New changeset 706689b2d678 by Victor Stinner in branch 'default':
Issue bpo-14180: TestDateTime.test_microsecond_rounding() handles localtime() and
http://hg.python.org/cpython/rev/706689b2d678

New changeset a0d101220f96 by Victor Stinner in branch 'default':
Issue bpo-14180: Fix the select module to handle correctly the Windows timeval
http://hg.python.org/cpython/rev/a0d101220f96