226 lines
8.3 KiB
C++
226 lines
8.3 KiB
C++
/*
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pybind11/chrono.h: Transparent conversion between std::chrono and python's datetime
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Copyright (c) 2016 Trent Houliston <trent@houliston.me> and
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Wenzel Jakob <wenzel.jakob@epfl.ch>
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All rights reserved. Use of this source code is governed by a
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BSD-style license that can be found in the LICENSE file.
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*/
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#pragma once
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#include "pybind11.h"
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#include <chrono>
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#include <cmath>
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#include <ctime>
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#include <datetime.h>
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#include <mutex>
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PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
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PYBIND11_NAMESPACE_BEGIN(detail)
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template <typename type>
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class duration_caster {
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public:
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using rep = typename type::rep;
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using period = typename type::period;
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// signed 25 bits required by the standard.
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using days = std::chrono::duration<int_least32_t, std::ratio<86400>>;
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bool load(handle src, bool) {
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using namespace std::chrono;
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// Lazy initialise the PyDateTime import
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if (!PyDateTimeAPI) {
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PyDateTime_IMPORT;
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}
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if (!src) {
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return false;
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}
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// If invoked with datetime.delta object
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if (PyDelta_Check(src.ptr())) {
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value = type(duration_cast<duration<rep, period>>(
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days(PyDateTime_DELTA_GET_DAYS(src.ptr()))
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+ seconds(PyDateTime_DELTA_GET_SECONDS(src.ptr()))
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+ microseconds(PyDateTime_DELTA_GET_MICROSECONDS(src.ptr()))));
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return true;
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}
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// If invoked with a float we assume it is seconds and convert
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if (PyFloat_Check(src.ptr())) {
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value = type(duration_cast<duration<rep, period>>(
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duration<double>(PyFloat_AsDouble(src.ptr()))));
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return true;
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}
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return false;
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}
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// If this is a duration just return it back
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static const std::chrono::duration<rep, period> &
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get_duration(const std::chrono::duration<rep, period> &src) {
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return src;
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}
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// If this is a time_point get the time_since_epoch
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template <typename Clock>
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static std::chrono::duration<rep, period>
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get_duration(const std::chrono::time_point<Clock, std::chrono::duration<rep, period>> &src) {
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return src.time_since_epoch();
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}
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static handle cast(const type &src, return_value_policy /* policy */, handle /* parent */) {
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using namespace std::chrono;
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// Use overloaded function to get our duration from our source
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// Works out if it is a duration or time_point and get the duration
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auto d = get_duration(src);
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// Lazy initialise the PyDateTime import
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if (!PyDateTimeAPI) {
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PyDateTime_IMPORT;
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}
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// Declare these special duration types so the conversions happen with the correct
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// primitive types (int)
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using dd_t = duration<int, std::ratio<86400>>;
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using ss_t = duration<int, std::ratio<1>>;
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using us_t = duration<int, std::micro>;
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auto dd = duration_cast<dd_t>(d);
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auto subd = d - dd;
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auto ss = duration_cast<ss_t>(subd);
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auto us = duration_cast<us_t>(subd - ss);
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return PyDelta_FromDSU(dd.count(), ss.count(), us.count());
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}
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PYBIND11_TYPE_CASTER(type, const_name("datetime.timedelta"));
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};
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inline std::tm *localtime_thread_safe(const std::time_t *time, std::tm *buf) {
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#if (defined(__STDC_LIB_EXT1__) && defined(__STDC_WANT_LIB_EXT1__)) || defined(_MSC_VER)
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if (localtime_s(buf, time))
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return nullptr;
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return buf;
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#else
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static std::mutex mtx;
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std::lock_guard<std::mutex> lock(mtx);
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std::tm *tm_ptr = std::localtime(time);
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if (tm_ptr != nullptr) {
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*buf = *tm_ptr;
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}
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return tm_ptr;
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#endif
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}
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// This is for casting times on the system clock into datetime.datetime instances
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template <typename Duration>
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class type_caster<std::chrono::time_point<std::chrono::system_clock, Duration>> {
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public:
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using type = std::chrono::time_point<std::chrono::system_clock, Duration>;
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bool load(handle src, bool) {
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using namespace std::chrono;
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// Lazy initialise the PyDateTime import
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if (!PyDateTimeAPI) {
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PyDateTime_IMPORT;
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}
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if (!src) {
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return false;
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}
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std::tm cal;
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microseconds msecs;
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if (PyDateTime_Check(src.ptr())) {
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cal.tm_sec = PyDateTime_DATE_GET_SECOND(src.ptr());
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cal.tm_min = PyDateTime_DATE_GET_MINUTE(src.ptr());
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cal.tm_hour = PyDateTime_DATE_GET_HOUR(src.ptr());
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cal.tm_mday = PyDateTime_GET_DAY(src.ptr());
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cal.tm_mon = PyDateTime_GET_MONTH(src.ptr()) - 1;
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cal.tm_year = PyDateTime_GET_YEAR(src.ptr()) - 1900;
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cal.tm_isdst = -1;
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msecs = microseconds(PyDateTime_DATE_GET_MICROSECOND(src.ptr()));
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} else if (PyDate_Check(src.ptr())) {
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cal.tm_sec = 0;
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cal.tm_min = 0;
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cal.tm_hour = 0;
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cal.tm_mday = PyDateTime_GET_DAY(src.ptr());
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cal.tm_mon = PyDateTime_GET_MONTH(src.ptr()) - 1;
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cal.tm_year = PyDateTime_GET_YEAR(src.ptr()) - 1900;
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cal.tm_isdst = -1;
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msecs = microseconds(0);
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} else if (PyTime_Check(src.ptr())) {
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cal.tm_sec = PyDateTime_TIME_GET_SECOND(src.ptr());
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cal.tm_min = PyDateTime_TIME_GET_MINUTE(src.ptr());
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cal.tm_hour = PyDateTime_TIME_GET_HOUR(src.ptr());
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cal.tm_mday = 1; // This date (day, month, year) = (1, 0, 70)
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cal.tm_mon = 0; // represents 1-Jan-1970, which is the first
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cal.tm_year = 70; // earliest available date for Python's datetime
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cal.tm_isdst = -1;
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msecs = microseconds(PyDateTime_TIME_GET_MICROSECOND(src.ptr()));
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} else {
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return false;
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}
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value = time_point_cast<Duration>(system_clock::from_time_t(std::mktime(&cal)) + msecs);
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return true;
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}
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static handle cast(const std::chrono::time_point<std::chrono::system_clock, Duration> &src,
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return_value_policy /* policy */,
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handle /* parent */) {
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using namespace std::chrono;
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// Lazy initialise the PyDateTime import
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if (!PyDateTimeAPI) {
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PyDateTime_IMPORT;
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}
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// Get out microseconds, and make sure they are positive, to avoid bug in eastern
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// hemisphere time zones (cfr. https://github.com/pybind/pybind11/issues/2417)
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using us_t = duration<int, std::micro>;
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auto us = duration_cast<us_t>(src.time_since_epoch() % seconds(1));
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if (us.count() < 0) {
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us += seconds(1);
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}
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// Subtract microseconds BEFORE `system_clock::to_time_t`, because:
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// > If std::time_t has lower precision, it is implementation-defined whether the value is
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// rounded or truncated. (https://en.cppreference.com/w/cpp/chrono/system_clock/to_time_t)
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std::time_t tt
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= system_clock::to_time_t(time_point_cast<system_clock::duration>(src - us));
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std::tm localtime;
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std::tm *localtime_ptr = localtime_thread_safe(&tt, &localtime);
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if (!localtime_ptr) {
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throw cast_error("Unable to represent system_clock in local time");
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}
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return PyDateTime_FromDateAndTime(localtime.tm_year + 1900,
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localtime.tm_mon + 1,
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localtime.tm_mday,
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localtime.tm_hour,
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localtime.tm_min,
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localtime.tm_sec,
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us.count());
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}
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PYBIND11_TYPE_CASTER(type, const_name("datetime.datetime"));
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};
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// Other clocks that are not the system clock are not measured as datetime.datetime objects
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// since they are not measured on calendar time. So instead we just make them timedeltas
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// Or if they have passed us a time as a float we convert that
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template <typename Clock, typename Duration>
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class type_caster<std::chrono::time_point<Clock, Duration>>
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: public duration_caster<std::chrono::time_point<Clock, Duration>> {};
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template <typename Rep, typename Period>
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class type_caster<std::chrono::duration<Rep, Period>>
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: public duration_caster<std::chrono::duration<Rep, Period>> {};
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PYBIND11_NAMESPACE_END(detail)
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PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
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