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//===----------------------------------------------------------------------===////
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===////
#ifndef FILESYSTEM_TIME_HELPER_H
#define FILESYSTEM_TIME_HELPER_H
#include "experimental/__config"
#include "chrono"
#include "cstdlib"
#include "climits"
#include <unistd.h>
#include <sys/stat.h>
#if !defined(UTIME_OMIT)
#include <sys/time.h> // for ::utimes as used in __last_write_time
#endif
_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM
namespace time_detail { namespace {
using namespace chrono;
template <class FileTimeT,
bool IsFloat = is_floating_point<typename FileTimeT::rep>::value>
struct fs_time_util_base {
static constexpr auto max_seconds =
duration_cast<seconds>(FileTimeT::duration::max()).count();
static constexpr auto max_nsec =
duration_cast<nanoseconds>(FileTimeT::duration::max() -
seconds(max_seconds))
.count();
static constexpr auto min_seconds =
duration_cast<seconds>(FileTimeT::duration::min()).count();
static constexpr auto min_nsec_timespec =
duration_cast<nanoseconds>(
(FileTimeT::duration::min() - seconds(min_seconds)) + seconds(1))
.count();
// Static assert that these values properly round trip.
static_assert((seconds(min_seconds) +
duration_cast<microseconds>(nanoseconds(min_nsec_timespec))) -
duration_cast<microseconds>(seconds(1)) ==
FileTimeT::duration::min(),
"");
};
template <class FileTimeT>
struct fs_time_util_base<FileTimeT, true> {
static const long long max_seconds;
static const long long max_nsec;
static const long long min_seconds;
static const long long min_nsec_timespec;
};
template <class FileTimeT>
const long long fs_time_util_base<FileTimeT, true>::max_seconds =
duration_cast<seconds>(FileTimeT::duration::max()).count();
template <class FileTimeT>
const long long fs_time_util_base<FileTimeT, true>::max_nsec =
duration_cast<nanoseconds>(FileTimeT::duration::max() -
seconds(max_seconds))
.count();
template <class FileTimeT>
const long long fs_time_util_base<FileTimeT, true>::min_seconds =
duration_cast<seconds>(FileTimeT::duration::min()).count();
template <class FileTimeT>
const long long fs_time_util_base<FileTimeT, true>::min_nsec_timespec =
duration_cast<nanoseconds>((FileTimeT::duration::min() -
seconds(min_seconds)) +
seconds(1))
.count();
template <class FileTimeT, class TimeT, class TimeSpecT>
struct fs_time_util : fs_time_util_base<FileTimeT> {
using Base = fs_time_util_base<FileTimeT>;
using Base::max_nsec;
using Base::max_seconds;
using Base::min_nsec_timespec;
using Base::min_seconds;
public:
template <class CType, class ChronoType>
static bool checked_set(CType* out, ChronoType time) {
using Lim = numeric_limits<CType>;
if (time > Lim::max() || time < Lim::min())
return false;
*out = static_cast<CType>(time);
return true;
}
static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool is_representable(TimeSpecT tm) {
if (tm.tv_sec >= 0) {
return (tm.tv_sec < max_seconds) ||
(tm.tv_sec == max_seconds && tm.tv_nsec <= max_nsec);
} else if (tm.tv_sec == (min_seconds - 1)) {
return tm.tv_nsec >= min_nsec_timespec;
} else {
return (tm.tv_sec >= min_seconds);
}
}
static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool is_representable(FileTimeT tm) {
auto secs = duration_cast<seconds>(tm.time_since_epoch());
auto nsecs = duration_cast<nanoseconds>(tm.time_since_epoch() - secs);
if (nsecs.count() < 0) {
secs = secs + seconds(1);
nsecs = nsecs + seconds(1);
}
using TLim = numeric_limits<TimeT>;
if (secs.count() >= 0)
return secs.count() <= TLim::max();
return secs.count() >= TLim::min();
}
static _LIBCPP_CONSTEXPR_AFTER_CXX11 FileTimeT
convert_timespec(TimeSpecT tm) {
auto adj_msec = duration_cast<microseconds>(nanoseconds(tm.tv_nsec));
if (tm.tv_sec >= 0) {
auto Dur = seconds(tm.tv_sec) + microseconds(adj_msec);
return FileTimeT(Dur);
} else if (duration_cast<microseconds>(nanoseconds(tm.tv_nsec)).count() ==
0) {
return FileTimeT(seconds(tm.tv_sec));
} else { // tm.tv_sec < 0
auto adj_subsec =
duration_cast<microseconds>(seconds(1) - nanoseconds(tm.tv_nsec));
auto Dur = seconds(tm.tv_sec + 1) - adj_subsec;
return FileTimeT(Dur);
}
}
template <class SubSecDurT, class SubSecT>
static bool set_times_checked(TimeT* sec_out, SubSecT* subsec_out,
FileTimeT tp) {
using namespace chrono;
auto dur = tp.time_since_epoch();
auto sec_dur = duration_cast<seconds>(dur);
auto subsec_dur = duration_cast<SubSecDurT>(dur - sec_dur);
// The tv_nsec and tv_usec fields must not be negative so adjust accordingly
if (subsec_dur.count() < 0) {
if (sec_dur.count() > min_seconds) {
sec_dur -= seconds(1);
subsec_dur += seconds(1);
} else {
subsec_dur = SubSecDurT::zero();
}
}
return checked_set(sec_out, sec_dur.count()) &&
checked_set(subsec_out, subsec_dur.count());
}
};
} // end namespace
} // end namespace time_detail
using time_detail::fs_time_util;
_LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM
#endif // FILESYSTEM_TIME_HELPER_H
|
