Refactor the chrono cast functions into chrono.h.
Add unit tests and documentation for the chrono cast.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 281de24..6124cf0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -161,6 +161,7 @@
set(PYBIND11_HEADERS
include/pybind11/attr.h
include/pybind11/cast.h
+ include/pybind11/chrono.h
include/pybind11/common.h
include/pybind11/complex.h
include/pybind11/descr.h
diff --git a/docs/advanced.rst b/docs/advanced.rst
index 1158f05..ae43d58 100644
--- a/docs/advanced.rst
+++ b/docs/advanced.rst
@@ -758,6 +758,29 @@
length queries (``__len__``), iterators (``__iter__``), the slicing
protocol and other kinds of useful operations.
+C++11 chrono datatypes
+======================
+When including the additional header file :file:`pybind11/chrono.h` conversions from c++11 chrono datatypes
+to corresponding python datetime objects are automatically enabled.
+The following rules describe how the conversions are applied.
+
+Objects of type ``std::chrono::system_clock::time_point`` are converted into datetime.datetime objects.
+These objects are those that specifically come from the system_clock as this is the only clock that measures wall time.
+
+Objects of type ``std::chrono::[other_clock]::time_point`` are converted into datetime.time objects.
+These objects are those that come from all clocks that are not the system_clock (e.g. steady_clock).
+Clocks other than the system_clock are not measured from wall date/time and instead have any start time
+(often when the computer was turned on).
+Therefore as these clocks can only measure time from an arbitrary start point they are represented as time without date.
+
+Objects of type ``std::chrono::duration`` are converted into datetime.timedelta objects.
+
+.. note::
+
+ Pythons datetime implementation is limited to microsecond precision.
+ The extra precision that c++11 clocks can have have (nanoseconds) will be lost upon conversion.
+ The rounding policy from c++ to python is via ``std::chrono::duration_cast<>`` (rounding towards 0 in microseconds).
+
Return value policies
=====================
diff --git a/docs/basics.rst b/docs/basics.rst
index 3e07e0e..339d559 100644
--- a/docs/basics.rst
+++ b/docs/basics.rst
@@ -297,6 +297,10 @@
+---------------------------------+--------------------------+-------------------------------+
| ``std::function<...>`` | STL polymorphic function | :file:`pybind11/functional.h` |
+---------------------------------+--------------------------+-------------------------------+
+| ``std::chrono::duration<...>`` | STL time duration | :file:`pybind11/chrono.h` |
++---------------------------------+--------------------------+-------------------------------+
+| ``std::chrono::time_point<...>``| STL date/time | :file:`pybind11/chrono.h` |
++---------------------------------+--------------------------+-------------------------------+
| ``Eigen::Matrix<...>`` | Eigen: dense matrix | :file:`pybind11/eigen.h` |
+---------------------------------+--------------------------+-------------------------------+
| ``Eigen::Map<...>`` | Eigen: mapped memory | :file:`pybind11/eigen.h` |
diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index 4a0c703..b885298 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -472,115 +472,6 @@
PYBIND11_TYPE_CASTER(bool, _("bool"));
};
-template <typename Rep, typename Period> class type_caster<std::chrono::duration<Rep, Period>> {
-public:
- typedef std::chrono::duration<Rep, Period> type;
- typedef std::chrono::duration<std::chrono::hours::rep, std::ratio<86400>> days;
-
- bool load(handle src, bool) {
- using namespace std::chrono;
- PyDateTime_IMPORT;
-
- if (!src) return false;
- if (PyDelta_Check(src.ptr())) {
- const PyDateTime_Delta* delta = reinterpret_cast<PyDateTime_Delta*>(src.ptr());
- value = duration_cast<duration<Rep, Period>>(
- days(delta->days)
- + seconds(delta->seconds)
- + microseconds(delta->microseconds));
- return true;
- }
- else return false;
- }
-
- static handle cast(const std::chrono::duration<Rep, Period> &src, return_value_policy /* policy */, handle /* parent */) {
- using namespace std::chrono;
- PyDateTime_IMPORT;
-
- int dd = duration_cast<days>(src).count();
- int ss = duration_cast<seconds>(src % days(1)).count();
- int us = duration_cast<microseconds>(src % seconds(1)).count();
-
- return PyDelta_FromDSU(dd, ss, us);
- }
- PYBIND11_TYPE_CASTER(type, _("datetime.timedelta"));
-};
-
-template <typename Duration> class type_caster<std::chrono::time_point<std::chrono::system_clock, Duration>> {
-public:
- typedef std::chrono::time_point<std::chrono::system_clock, Duration> type;
- bool load(handle src, bool) {
- using namespace std::chrono;
- PyDateTime_IMPORT;
-
- if (!src) return false;
- if (PyDateTime_Check(src.ptr())) {
- std::tm cal;
- cal.tm_sec = PyDateTime_DATE_GET_SECOND(src.ptr());
- cal.tm_min = PyDateTime_DATE_GET_MINUTE(src.ptr());
- cal.tm_hour = PyDateTime_DATE_GET_HOUR(src.ptr());
- cal.tm_mday = PyDateTime_GET_DAY(src.ptr());
- cal.tm_mon = PyDateTime_GET_MONTH(src.ptr()) - 1;
- cal.tm_year = PyDateTime_GET_YEAR(src.ptr());
- cal.tm_isdst = -1;
-
- value = system_clock::from_time_t(mktime(&cal));
- return true;
- }
- else return false;
- }
-
- static handle cast(const std::chrono::time_point<std::chrono::system_clock, Duration> &src, return_value_policy /* policy */, handle /* parent */) {
- using namespace std::chrono;
- PyDateTime_IMPORT;
-
- time_t tt = system_clock::to_time_t(src);
- tm *ltime = localtime(&tt); // this function uses static memory so it's best
- tm localtime = *ltime; // to copy it out asap just in case
-
- return PyDateTime_FromDateAndTime(localtime.tm_year, localtime.tm_mon + 1
- , localtime.tm_mday
- , localtime.tm_hour
- , localtime.tm_min
- , localtime.tm_sec
- , (duration_cast<microseconds>(src.time_since_epoch()) % seconds(1)).count());
- }
- PYBIND11_TYPE_CASTER(type, _("datetime.datetime"));
-};
-
-template <typename Clock, typename Duration> class type_caster<std::chrono::time_point<Clock, Duration>> {
-public:
- typedef std::chrono::time_point<Clock, Duration> type;
- bool load(handle src, bool) {
- using namespace std::chrono;
- PyDateTime_IMPORT;
-
- if (!src) return false;
- if (PyTime_Check(src.ptr())) {
- value = type(duration_cast<Duration>(
- hours(PyDateTime_TIME_GET_HOUR(src.ptr()))
- + minutes(PyDateTime_TIME_GET_MINUTE(src.ptr()))
- + seconds(PyDateTime_TIME_GET_SECOND(src.ptr()))
- + microseconds(PyDateTime_TIME_GET_MICROSECOND(src.ptr()))
- ));
- return true;
- }
- else return false;
- }
-
- static handle cast(const std::chrono::time_point<Clock, Duration> &src, return_value_policy /* policy */, handle /* parent */) {
- using namespace std::chrono;
- PyDateTime_IMPORT;
-
- Duration d = src.time_since_epoch();
- return PyTime_FromTime(duration_cast<hours>(d).count()
- , duration_cast<minutes>(d % hours(1)).count()
- , duration_cast<seconds>(d % minutes(1)).count()
- , duration_cast<microseconds>(d % seconds(1)).count());
- }
- PYBIND11_TYPE_CASTER(type, _("datetime.time"));
-};
-
template <> class type_caster<std::string> {
public:
bool load(handle src, bool) {
diff --git a/include/pybind11/chrono.h b/include/pybind11/chrono.h
new file mode 100644
index 0000000..d82f143
--- /dev/null
+++ b/include/pybind11/chrono.h
@@ -0,0 +1,146 @@
+/*
+ pybind11/chrono.h: Transparent conversion between std::chrono and python's datetime
+
+ Copyright (c) 2016 Trent Houliston <trent@houliston.me> and
+ Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+ All rights reserved. Use of this source code is governed by a
+ BSD-style license that can be found in the LICENSE file.
+*/
+
+#pragma once
+
+#include "pybind11.h"
+#include <chrono>
+
+NAMESPACE_BEGIN(pybind11)
+NAMESPACE_BEGIN(detail)
+
+template <typename Rep, typename Period> class type_caster<std::chrono::duration<Rep, Period>> {
+public:
+ typedef std::chrono::duration<Rep, Period> type;
+ typedef std::chrono::duration<std::chrono::hours::rep, std::ratio<86400>> days;
+
+ bool load(handle src, bool) {
+ using namespace std::chrono;
+ PyDateTime_IMPORT;
+
+ if (!src) return false;
+ if (PyDelta_Check(src.ptr())) {
+ // The accessor macros for timedelta exist in some versions of python but not others (e.g. Mac OSX default python)
+ // Therefore we are just doing what the macros do explicitly
+ const PyDateTime_Delta* delta = reinterpret_cast<PyDateTime_Delta*>(src.ptr());
+ value = duration_cast<duration<Rep, Period>>(
+ days(delta->days)
+ + seconds(delta->seconds)
+ + microseconds(delta->microseconds));
+ return true;
+ }
+ else return false;
+ }
+
+ static handle cast(const std::chrono::duration<Rep, Period> &src, return_value_policy /* policy */, handle /* parent */) {
+ using namespace std::chrono;
+ PyDateTime_IMPORT;
+
+ // Declare these special duration types so the conversions happen with the correct primitive types (int)
+ typedef duration<int, std::ratio<86400>> dd_t;
+ typedef duration<int, std::ratio<1>> ss_t;
+ typedef duration<int, std::micro> us_t;
+
+ return PyDelta_FromDSU(
+ duration_cast<dd_t>(src).count()
+ , duration_cast<ss_t>(src % days(1)).count()
+ , duration_cast<us_t>(src % seconds(1)).count());
+ }
+ PYBIND11_TYPE_CASTER(type, _("datetime.timedelta"));
+};
+
+template <typename Duration> class type_caster<std::chrono::time_point<std::chrono::system_clock, Duration>> {
+public:
+ typedef std::chrono::time_point<std::chrono::system_clock, Duration> type;
+ bool load(handle src, bool) {
+ using namespace std::chrono;
+ PyDateTime_IMPORT;
+
+ if (!src) return false;
+ if (PyDateTime_Check(src.ptr())) {
+ std::tm cal;
+ cal.tm_sec = PyDateTime_DATE_GET_SECOND(src.ptr());
+ cal.tm_min = PyDateTime_DATE_GET_MINUTE(src.ptr());
+ cal.tm_hour = PyDateTime_DATE_GET_HOUR(src.ptr());
+ cal.tm_mday = PyDateTime_GET_DAY(src.ptr());
+ cal.tm_mon = PyDateTime_GET_MONTH(src.ptr()) - 1;
+ cal.tm_year = PyDateTime_GET_YEAR(src.ptr()) - 1900;
+ cal.tm_isdst = -1;
+
+ value = system_clock::from_time_t(mktime(&cal)) + microseconds(PyDateTime_DATE_GET_MICROSECOND(src.ptr()));
+ return true;
+ }
+ else return false;
+ }
+
+ static handle cast(const std::chrono::time_point<std::chrono::system_clock, Duration> &src, return_value_policy /* policy */, handle /* parent */) {
+ using namespace std::chrono;
+ PyDateTime_IMPORT;
+
+ time_t tt = system_clock::to_time_t(src);
+ // this function uses static memory so it's best to copy it out asap just in case
+ tm *ltime = localtime(&tt);
+ tm localtime = *ltime;
+
+ // Declare these special duration types so the conversions happen with the correct primitive types (int)
+ using us_t = duration<int, std::micro>;
+
+ return PyDateTime_FromDateAndTime(localtime.tm_year + 1900
+ , localtime.tm_mon + 1
+ , localtime.tm_mday
+ , localtime.tm_hour
+ , localtime.tm_min
+ , localtime.tm_sec
+ , (duration_cast<us_t>(src.time_since_epoch() % seconds(1))).count());
+ }
+ PYBIND11_TYPE_CASTER(type, _("datetime.datetime"));
+};
+
+template <typename Clock, typename Duration> class type_caster<std::chrono::time_point<Clock, Duration>> {
+public:
+ typedef std::chrono::time_point<Clock, Duration> type;
+ bool load(handle src, bool) {
+ using namespace std::chrono;
+ PyDateTime_IMPORT;
+
+ if (!src) return false;
+ if (PyTime_Check(src.ptr())) {
+ value = type(duration_cast<Duration>(
+ hours(PyDateTime_TIME_GET_HOUR(src.ptr()))
+ + minutes(PyDateTime_TIME_GET_MINUTE(src.ptr()))
+ + seconds(PyDateTime_TIME_GET_SECOND(src.ptr()))
+ + microseconds(PyDateTime_TIME_GET_MICROSECOND(src.ptr()))
+ ));
+ return true;
+ }
+ else return false;
+ }
+
+ static handle cast(const std::chrono::time_point<Clock, Duration> &src, return_value_policy /* policy */, handle /* parent */) {
+ using namespace std::chrono;
+ PyDateTime_IMPORT;
+
+ // Declare these special duration types so the conversions happen with the correct primitive types (int)
+ typedef duration<int, std::ratio<3600>> hh_t;
+ typedef duration<int, std::ratio<60>> mm_t;
+ typedef duration<int, std::ratio<1>> ss_t;
+ typedef duration<int, std::micro> us_t;
+
+ Duration d = src.time_since_epoch();
+ return PyTime_FromTime(duration_cast<hh_t>(d).count()
+ , duration_cast<mm_t>(d % hours(1)).count()
+ , duration_cast<ss_t>(d % minutes(1)).count()
+ , duration_cast<us_t>(d % seconds(1)).count());
+ }
+ PYBIND11_TYPE_CASTER(type, _("datetime.time"));
+};
+
+NAMESPACE_END(detail)
+NAMESPACE_END(pybind11)
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 3be8cf8..6274ca1 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -7,6 +7,7 @@
test_alias_initialization.cpp
test_buffers.cpp
test_callbacks.cpp
+ test_chrono.cpp
test_class_args.cpp
test_constants_and_functions.cpp
test_eigen.cpp
diff --git a/tests/test_chrono.cpp b/tests/test_chrono.cpp
new file mode 100644
index 0000000..e071924
--- /dev/null
+++ b/tests/test_chrono.cpp
@@ -0,0 +1,53 @@
+/*
+ tests/test_chrono.cpp -- test conversions to/from std::chrono types
+
+ Copyright (c) 2016 Trent Houliston <trent@houliston.me> and
+ Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+ All rights reserved. Use of this source code is governed by a
+ BSD-style license that can be found in the LICENSE file.
+*/
+
+
+#include "pybind11_tests.h"
+#include "constructor_stats.h"
+#include <pybind11/chrono.h>
+
+// Return the current time off the wall clock
+std::chrono::system_clock::time_point test_chrono1() {
+ return std::chrono::system_clock::now();
+}
+
+// Round trip the passed in system clock time
+std::chrono::system_clock::time_point test_chrono2(std::chrono::system_clock::time_point t) {
+ return t;
+}
+
+// Round trip the passed in duration
+std::chrono::system_clock::duration test_chrono3(std::chrono::system_clock::duration d) {
+ return d;
+}
+
+// Difference between two passed in time_points
+std::chrono::system_clock::duration test_chrono4(std::chrono::system_clock::time_point a, std::chrono::system_clock::time_point b) {
+ return a - b;
+}
+
+// Return the current time off the steady_clock
+std::chrono::steady_clock::time_point test_chrono5() {
+ return std::chrono::steady_clock::now();
+}
+
+// Round trip a steady clock timepoint
+std::chrono::steady_clock::time_point test_chrono6(std::chrono::steady_clock::time_point t) {
+ return t;
+}
+
+test_initializer chrono([] (py::module &m) {
+ m.def("test_chrono1", &test_chrono1);
+ m.def("test_chrono2", &test_chrono2);
+ m.def("test_chrono3", &test_chrono3);
+ m.def("test_chrono4", &test_chrono4);
+ m.def("test_chrono5", &test_chrono5);
+ m.def("test_chrono6", &test_chrono6);
+});
diff --git a/tests/test_chrono.py b/tests/test_chrono.py
new file mode 100644
index 0000000..aa47480
--- /dev/null
+++ b/tests/test_chrono.py
@@ -0,0 +1,102 @@
+
+
+def test_chrono_system_clock():
+ from pybind11_tests import test_chrono1
+ import datetime
+
+ # Get the time from both c++ and datetime
+ date1 = test_chrono1()
+ date2 = datetime.datetime.today()
+
+ # The returned value should be a datetime
+ assert isinstance(date1, datetime.datetime)
+
+ # The numbers should vary by a very small amount (time it took to execute)
+ diff = abs(date1 - date2)
+
+ # There should never be a days/seconds difference
+ assert diff.days == 0
+ assert diff.seconds == 0
+
+ # 500 microseconds is a very long time to execute this
+ assert diff.microseconds < 500
+
+
+def test_chrono_system_clock_roundtrip():
+ from pybind11_tests import test_chrono2
+ import datetime
+
+ date1 = datetime.datetime.today()
+
+ # Roundtrip the time
+ date2 = test_chrono2(date1)
+
+ # The returned value should be a datetime
+ assert isinstance(date2, datetime.datetime)
+
+ # They should be identical (no information lost on roundtrip)
+ diff = abs(date1 - date2)
+ assert diff.days == 0
+ assert diff.seconds == 0
+ assert diff.microseconds == 0
+
+
+def test_chrono_duration_roundtrip():
+ from pybind11_tests import test_chrono3
+ import datetime
+
+ # Get the difference betwen two times (a timedelta)
+ date1 = datetime.datetime.today()
+ date2 = datetime.datetime.today()
+ diff = date2 - date1
+
+ # Make sure this is a timedelta
+ assert isinstance(diff, datetime.timedelta)
+
+ cpp_diff = test_chrono3(diff)
+
+ assert cpp_diff.days == diff.days
+ assert cpp_diff.seconds == diff.seconds
+ assert cpp_diff.microseconds == diff.microseconds
+
+
+def test_chrono_duration_subtraction_equivalence():
+ from pybind11_tests import test_chrono4
+ import datetime
+
+ date1 = datetime.datetime.today()
+ date2 = datetime.datetime.today()
+
+ diff = date2 - date1
+ cpp_diff = test_chrono4(date2, date1)
+
+ assert cpp_diff.days == diff.days
+ assert cpp_diff.seconds == diff.seconds
+ assert cpp_diff.microseconds == diff.microseconds
+
+
+def test_chrono_steady_clock():
+ from pybind11_tests import test_chrono5
+ import datetime
+
+ time1 = test_chrono5()
+ time2 = test_chrono5()
+
+ assert isinstance(time1, datetime.time)
+ assert isinstance(time2, datetime.time)
+
+
+def test_chrono_steady_clock_roundtrip():
+ from pybind11_tests import test_chrono6
+ import datetime
+
+ time1 = datetime.time(second=10, microsecond=100)
+ time2 = test_chrono6(time1)
+
+ assert isinstance(time2, datetime.time)
+
+ # They should be identical (no information lost on roundtrip)
+ assert time1.hour == time2.hour
+ assert time1.minute == time2.minute
+ assert time1.second == time2.second
+ assert time1.microsecond == time2.microsecond