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authorpatrick <patrick@openbsd.org>2021-01-02 20:29:13 +0000
committerpatrick <patrick@openbsd.org>2021-01-02 20:29:13 +0000
commit46035553bfdd96e63c94e32da0210227ec2e3cf1 (patch)
treeb191f708fb9a2995ba745b2f31cdeeaee4872b7f /gnu/llvm/libcxx/src/chrono.cpp
parentMove Makefiles for libc++ and libc++abi to gnu/lib in preparation for an (diff)
downloadwireguard-openbsd-46035553bfdd96e63c94e32da0210227ec2e3cf1.tar.xz
wireguard-openbsd-46035553bfdd96e63c94e32da0210227ec2e3cf1.zip
Import libc++ 10.0.1 release.
Diffstat (limited to 'gnu/llvm/libcxx/src/chrono.cpp')
-rw-r--r--gnu/llvm/libcxx/src/chrono.cpp233
1 files changed, 233 insertions, 0 deletions
diff --git a/gnu/llvm/libcxx/src/chrono.cpp b/gnu/llvm/libcxx/src/chrono.cpp
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+++ b/gnu/llvm/libcxx/src/chrono.cpp
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+//===------------------------- chrono.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "chrono"
+#include "cerrno" // errno
+#include "system_error" // __throw_system_error
+#include <time.h> // clock_gettime, CLOCK_MONOTONIC and CLOCK_REALTIME
+#include "include/apple_availability.h"
+
+#if !defined(__APPLE__)
+#define _LIBCPP_USE_CLOCK_GETTIME
+#endif // __APPLE__
+
+#if defined(_LIBCPP_WIN32API)
+#define WIN32_LEAN_AND_MEAN
+#define VC_EXTRA_LEAN
+#include <windows.h>
+#if _WIN32_WINNT >= _WIN32_WINNT_WIN8
+#include <winapifamily.h>
+#endif
+#else
+#if !defined(CLOCK_REALTIME) || !defined(_LIBCPP_USE_CLOCK_GETTIME)
+#include <sys/time.h> // for gettimeofday and timeval
+#endif // !defined(CLOCK_REALTIME)
+#endif // defined(_LIBCPP_WIN32API)
+
+#if !defined(_LIBCPP_HAS_NO_MONOTONIC_CLOCK)
+#if __APPLE__
+#include <mach/mach_time.h> // mach_absolute_time, mach_timebase_info_data_t
+#elif !defined(_LIBCPP_WIN32API) && !defined(CLOCK_MONOTONIC)
+#error "Monotonic clock not implemented"
+#endif
+#endif
+
+#if defined(__ELF__) && defined(_LIBCPP_LINK_RT_LIB)
+#pragma comment(lib, "rt")
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace chrono
+{
+
+// system_clock
+
+const bool system_clock::is_steady;
+
+system_clock::time_point
+system_clock::now() _NOEXCEPT
+{
+#if defined(_LIBCPP_WIN32API)
+ // FILETIME is in 100ns units
+ using filetime_duration =
+ _VSTD::chrono::duration<__int64,
+ _VSTD::ratio_multiply<_VSTD::ratio<100, 1>,
+ nanoseconds::period>>;
+
+ // The Windows epoch is Jan 1 1601, the Unix epoch Jan 1 1970.
+ static _LIBCPP_CONSTEXPR const seconds nt_to_unix_epoch{11644473600};
+
+ FILETIME ft;
+#if _WIN32_WINNT >= _WIN32_WINNT_WIN8
+#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+ GetSystemTimePreciseAsFileTime(&ft);
+#else
+ GetSystemTimeAsFileTime(&ft);
+#endif
+#else
+ GetSystemTimeAsFileTime(&ft);
+#endif
+
+ filetime_duration d{(static_cast<__int64>(ft.dwHighDateTime) << 32) |
+ static_cast<__int64>(ft.dwLowDateTime)};
+ return time_point(duration_cast<duration>(d - nt_to_unix_epoch));
+#else
+#if defined(_LIBCPP_USE_CLOCK_GETTIME) && defined(CLOCK_REALTIME)
+ struct timespec tp;
+ if (0 != clock_gettime(CLOCK_REALTIME, &tp))
+ __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");
+ return time_point(seconds(tp.tv_sec) + microseconds(tp.tv_nsec / 1000));
+#else
+ timeval tv;
+ gettimeofday(&tv, 0);
+ return time_point(seconds(tv.tv_sec) + microseconds(tv.tv_usec));
+#endif // _LIBCPP_USE_CLOCK_GETTIME && CLOCK_REALTIME
+#endif
+}
+
+time_t
+system_clock::to_time_t(const time_point& t) _NOEXCEPT
+{
+ return time_t(duration_cast<seconds>(t.time_since_epoch()).count());
+}
+
+system_clock::time_point
+system_clock::from_time_t(time_t t) _NOEXCEPT
+{
+ return system_clock::time_point(seconds(t));
+}
+
+#ifndef _LIBCPP_HAS_NO_MONOTONIC_CLOCK
+// steady_clock
+//
+// Warning: If this is not truly steady, then it is non-conforming. It is
+// better for it to not exist and have the rest of libc++ use system_clock
+// instead.
+
+const bool steady_clock::is_steady;
+
+#if defined(__APPLE__)
+
+// Darwin libc versions >= 1133 provide ns precision via CLOCK_UPTIME_RAW
+#if defined(_LIBCPP_USE_CLOCK_GETTIME) && defined(CLOCK_UPTIME_RAW)
+steady_clock::time_point
+steady_clock::now() _NOEXCEPT
+{
+ struct timespec tp;
+ if (0 != clock_gettime(CLOCK_UPTIME_RAW, &tp))
+ __throw_system_error(errno, "clock_gettime(CLOCK_UPTIME_RAW) failed");
+ return time_point(seconds(tp.tv_sec) + nanoseconds(tp.tv_nsec));
+}
+
+#else
+// mach_absolute_time() * MachInfo.numer / MachInfo.denom is the number of
+// nanoseconds since the computer booted up. MachInfo.numer and MachInfo.denom
+// are run time constants supplied by the OS. This clock has no relationship
+// to the Gregorian calendar. It's main use is as a high resolution timer.
+
+// MachInfo.numer / MachInfo.denom is often 1 on the latest equipment. Specialize
+// for that case as an optimization.
+
+static
+steady_clock::rep
+steady_simplified()
+{
+ return static_cast<steady_clock::rep>(mach_absolute_time());
+}
+
+static
+double
+compute_steady_factor()
+{
+ mach_timebase_info_data_t MachInfo;
+ mach_timebase_info(&MachInfo);
+ return static_cast<double>(MachInfo.numer) / MachInfo.denom;
+}
+
+static
+steady_clock::rep
+steady_full()
+{
+ static const double factor = compute_steady_factor();
+ return static_cast<steady_clock::rep>(mach_absolute_time() * factor);
+}
+
+typedef steady_clock::rep (*FP)();
+
+static
+FP
+init_steady_clock()
+{
+ mach_timebase_info_data_t MachInfo;
+ mach_timebase_info(&MachInfo);
+ if (MachInfo.numer == MachInfo.denom)
+ return &steady_simplified;
+ return &steady_full;
+}
+
+steady_clock::time_point
+steady_clock::now() _NOEXCEPT
+{
+ static FP fp = init_steady_clock();
+ return time_point(duration(fp()));
+}
+#endif // defined(_LIBCPP_USE_CLOCK_GETTIME) && defined(CLOCK_UPTIME_RAW)
+
+#elif defined(_LIBCPP_WIN32API)
+
+// https://msdn.microsoft.com/en-us/library/windows/desktop/ms644905(v=vs.85).aspx says:
+// If the function fails, the return value is zero. <snip>
+// On systems that run Windows XP or later, the function will always succeed
+// and will thus never return zero.
+
+static LARGE_INTEGER
+__QueryPerformanceFrequency()
+{
+ LARGE_INTEGER val;
+ (void) QueryPerformanceFrequency(&val);
+ return val;
+}
+
+steady_clock::time_point
+steady_clock::now() _NOEXCEPT
+{
+ static const LARGE_INTEGER freq = __QueryPerformanceFrequency();
+
+ LARGE_INTEGER counter;
+ (void) QueryPerformanceCounter(&counter);
+ return time_point(duration(counter.QuadPart * nano::den / freq.QuadPart));
+}
+
+#elif defined(CLOCK_MONOTONIC)
+
+// On Apple platforms only CLOCK_UPTIME_RAW or mach_absolute_time are able to
+// time functions in the nanosecond range. Thus, they are the only acceptable
+// implementations of steady_clock.
+#ifdef __APPLE__
+#error "Never use CLOCK_MONOTONIC for steady_clock::now on Apple platforms"
+#endif
+
+steady_clock::time_point
+steady_clock::now() _NOEXCEPT
+{
+ struct timespec tp;
+ if (0 != clock_gettime(CLOCK_MONOTONIC, &tp))
+ __throw_system_error(errno, "clock_gettime(CLOCK_MONOTONIC) failed");
+ return time_point(seconds(tp.tv_sec) + nanoseconds(tp.tv_nsec));
+}
+
+#else
+#error "Monotonic clock not implemented"
+#endif
+
+#endif // !_LIBCPP_HAS_NO_MONOTONIC_CLOCK
+
+}
+
+_LIBCPP_END_NAMESPACE_STD