date/include/date/ptz.h
2024-05-10 16:26:43 -04:00

951 lines
27 KiB
C++

#ifndef PTZ_H
#define PTZ_H
// The MIT License (MIT)
//
// Copyright (c) 2017 Howard Hinnant
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
// This header allows Posix-style time zones as specified for TZ here:
// http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03
//
// Posix::time_zone can be constructed with a posix-style string and then used in
// a zoned_time like so:
//
// zoned_time<system_clock::duration, Posix::time_zone> zt{"EST5EDT,M3.2.0,M11.1.0",
// system_clock::now()};
// or:
//
// Posix::time_zone tz{"EST5EDT,M3.2.0,M11.1.0"};
// zoned_time<system_clock::duration, Posix::time_zone> zt{tz, system_clock::now()};
//
// In C++17 CTAD simplifies this to:
//
// Posix::time_zone tz{"EST5EDT,M3.2.0,M11.1.0"};
// zoned_time zt{tz, system_clock::now()};
//
// Extension to the Posix rules to allow a constant daylight saving offset:
//
// If the rule set is missing (everything starting with ','), then
// there must be exactly one abbreviation (std or daylight) with
// length 3 or greater, and that will be used as the constant offset. If
// there are two, the std abbreviation is silently set to "", and the
// result is constant daylight saving. If there are zero abbreviations
// with no rule set, an exception is thrown.
//
// Example:
// "EST5" yields a constant offset of -5h with 0h save and "EST abbreviation.
// "5EDT" yields a constant offset of -4h with 1h save and "EDT" abbreviation.
// "EST5EDT" and "5EDT4" are both equal to "5EDT".
//
// Note, Posix-style time zones are not recommended for all of the reasons described here:
// https://stackoverflow.com/tags/timezone/info
//
// They are provided here as a non-trivial custom time zone example, and if you really
// have to have Posix time zones, you're welcome to use this one.
#include "date/tz.h"
#include <algorithm>
#include <cctype>
#include <ostream>
#include <string>
namespace Posix
{
namespace detail
{
#if HAS_STRING_VIEW
using string_t = std::string_view;
#else // !HAS_STRING_VIEW
using string_t = std::string;
#endif // !HAS_STRING_VIEW
class rule;
void throw_invalid(const string_t& s, unsigned i, const string_t& message);
unsigned read_date(const string_t& s, unsigned i, rule& r);
unsigned read_name(const string_t& s, unsigned i, std::string& name);
unsigned read_signed_time(const string_t& s, unsigned i, std::chrono::seconds& t);
unsigned read_unsigned_time(const string_t& s, unsigned i, std::chrono::seconds& t);
unsigned read_unsigned(const string_t& s, unsigned i, unsigned limit, unsigned& u,
const string_t& message = string_t{});
class rule
{
enum {off, J, M, N};
date::month m_;
date::weekday wd_;
unsigned short n_ : 14;
unsigned short mode_ : 2;
std::chrono::duration<std::int32_t> time_ = std::chrono::hours{2};
public:
rule() : mode_(off) {}
bool ok() const {return mode_ != off;}
date::local_seconds operator()(date::year y) const;
std::string to_string() const;
friend std::ostream& operator<<(std::ostream& os, const rule& r);
friend unsigned read_date(const string_t& s, unsigned i, rule& r);
friend bool operator==(const rule& x, const rule& y);
};
inline
bool
operator==(const rule& x, const rule& y)
{
if (x.mode_ != y.mode_)
return false;
switch (x.mode_)
{
case rule::J:
case rule::N:
return x.n_ == y.n_;
case rule::M:
return x.m_ == y.m_ && x.n_ == y.n_ && x.wd_ == y.wd_;
default:
return true;
}
}
inline
bool
operator!=(const rule& x, const rule& y)
{
return !(x == y);
}
inline
date::local_seconds
rule::operator()(date::year y) const
{
using date::local_days;
using date::January;
using date::days;
using date::last;
using sec = std::chrono::seconds;
date::local_seconds t;
switch (mode_)
{
case J:
t = local_days{y/January/0} + days{n_ + (y.is_leap() && n_ > 59)} + sec{time_};
break;
case M:
t = (n_ == 5 ? local_days{y/m_/wd_[last]} : local_days{y/m_/wd_[n_]}) + sec{time_};
break;
case N:
t = local_days{y/January/1} + days{n_} + sec{time_};
break;
default:
assert(!"rule called with bad mode");
}
return t;
}
inline
std::string
rule::to_string() const
{
using namespace std::chrono;
auto print_offset = [](seconds off)
{
std::string nm;
if (off != hours{2})
{
date::hh_mm_ss<seconds> offset{off};
nm = '/';
nm += std::to_string(offset.hours().count());
if (offset.minutes() != minutes{0} || offset.seconds() != seconds{0})
{
nm += ':';
if (offset.minutes() < minutes{10})
nm += '0';
nm += std::to_string(offset.minutes().count());
if (offset.seconds() != seconds{0})
{
nm += ':';
if (offset.seconds() < seconds{10})
nm += '0';
nm += std::to_string(offset.seconds().count());
}
}
}
return nm;
};
std::string nm;
switch (mode_)
{
case rule::J:
nm = 'J';
nm += std::to_string(n_);
break;
case rule::M:
nm = 'M';
nm += std::to_string(static_cast<unsigned>(m_));
nm += '.';
nm += std::to_string(n_);
nm += '.';
nm += std::to_string(wd_.c_encoding());
break;
case rule::N:
nm = std::to_string(n_);
break;
default:
break;
}
nm += print_offset(time_);
return nm;
}
inline
std::ostream&
operator<<(std::ostream& os, const rule& r)
{
switch (r.mode_)
{
case rule::J:
os << 'J' << r.n_ << date::format(" %T", r.time_);
break;
case rule::M:
if (r.n_ == 5)
os << r.m_/r.wd_[date::last];
else
os << r.m_/r.wd_[r.n_];
os << date::format(" %T", r.time_);
break;
case rule::N:
os << r.n_ << date::format(" %T", r.time_);
break;
default:
break;
}
return os;
}
} // namespace detail
class time_zone
{
std::string std_abbrev_;
std::string dst_abbrev_ = {};
std::chrono::seconds offset_;
std::chrono::seconds save_ = std::chrono::hours{1};
detail::rule start_rule_;
detail::rule end_rule_;
public:
explicit time_zone(const detail::string_t& name);
template <class Duration>
date::sys_info get_info(date::sys_time<Duration> st) const;
template <class Duration>
date::local_info get_info(date::local_time<Duration> tp) const;
template <class Duration>
date::sys_time<typename std::common_type<Duration, std::chrono::seconds>::type>
to_sys(date::local_time<Duration> tp) const;
template <class Duration>
date::sys_time<typename std::common_type<Duration, std::chrono::seconds>::type>
to_sys(date::local_time<Duration> tp, date::choose z) const;
template <class Duration>
date::local_time<typename std::common_type<Duration, std::chrono::seconds>::type>
to_local(date::sys_time<Duration> tp) const;
friend std::ostream& operator<<(std::ostream& os, const time_zone& z);
const time_zone* operator->() const {return this;}
std::string name() const;
friend bool operator==(const time_zone& x, const time_zone& y);
private:
date::sys_seconds get_start(date::year y) const;
date::sys_seconds get_prev_start(date::year y) const;
date::sys_seconds get_next_start(date::year y) const;
date::sys_seconds get_end(date::year y) const;
date::sys_seconds get_prev_end(date::year y) const;
date::sys_seconds get_next_end(date::year y) const;
date::sys_info contant_offset() const;
};
inline
date::sys_seconds
time_zone::get_start(date::year y) const
{
return date::sys_seconds{(start_rule_(y) - offset_).time_since_epoch()};
}
inline
date::sys_seconds
time_zone::get_prev_start(date::year y) const
{
return date::sys_seconds{(start_rule_(--y) - offset_).time_since_epoch()};
}
inline
date::sys_seconds
time_zone::get_next_start(date::year y) const
{
return date::sys_seconds{(start_rule_(++y) - offset_).time_since_epoch()};
}
inline
date::sys_seconds
time_zone::get_end(date::year y) const
{
return date::sys_seconds{(end_rule_(y) - (offset_ + save_)).time_since_epoch()};
}
inline
date::sys_seconds
time_zone::get_prev_end(date::year y) const
{
return date::sys_seconds{(end_rule_(--y) - (offset_ + save_)).time_since_epoch()};
}
inline
date::sys_seconds
time_zone::get_next_end(date::year y) const
{
return date::sys_seconds{(end_rule_(++y) - (offset_ + save_)).time_since_epoch()};
}
inline
date::sys_info
time_zone::contant_offset() const
{
using date::year;
using date::sys_info;
using date::sys_days;
using date::January;
using date::December;
using date::last;
using std::chrono::minutes;
sys_info r;
r.begin = sys_days{year::min()/January/1};
r.end = sys_days{year::max()/December/last};
if (std_abbrev_.size() > 0)
{
r.abbrev = std_abbrev_;
r.offset = offset_;
r.save = {};
}
else
{
r.abbrev = dst_abbrev_;
r.offset = offset_ + save_;
r.save = date::ceil<minutes>(save_);
}
return r;
}
inline
time_zone::time_zone(const detail::string_t& s)
{
using detail::read_name;
using detail::read_signed_time;
using detail::throw_invalid;
auto i = read_name(s, 0, std_abbrev_);
auto std_name_i = i;
auto abbrev_name_i = i;
i = read_signed_time(s, i, offset_);
offset_ = -offset_;
if (i != s.size())
{
i = read_name(s, i, dst_abbrev_);
abbrev_name_i = i;
if (i != s.size())
{
if (s[i] != ',')
{
i = read_signed_time(s, i, save_);
save_ = -save_ - offset_;
}
if (i != s.size())
{
if (s[i] != ',')
throw_invalid(s, i, "Expecting end of string or ',' to start rule");
++i;
i = read_date(s, i, start_rule_);
if (i == s.size() || s[i] != ',')
throw_invalid(s, i, "Expecting ',' and then the ending rule");
++i;
i = read_date(s, i, end_rule_);
if (i != s.size())
throw_invalid(s, i, "Found unexpected trailing characters");
}
}
}
if (start_rule_.ok())
{
if (std_abbrev_.size() < 3)
throw_invalid(s, std_name_i, "Zone with rules must have a std"
" abbreviation of length 3 or greater");
if (dst_abbrev_.size() < 3)
throw_invalid(s, abbrev_name_i, "Zone with rules must have a daylight"
" abbreviation of length 3 or greater");
}
else
{
if (dst_abbrev_.size() >= 3)
{
std_abbrev_.clear();
}
else if (std_abbrev_.size() < 3)
{
throw_invalid(s, std_name_i, "Zone must have at least one abbreviation"
" of length 3 or greater");
}
else
{
dst_abbrev_.clear();
save_ = {};
}
}
}
template <class Duration>
date::sys_info
time_zone::get_info(date::sys_time<Duration> st) const
{
using date::sys_info;
using date::year_month_day;
using date::sys_days;
using date::floor;
using date::ceil;
using date::days;
using date::year;
using date::January;
using date::December;
using date::last;
using std::chrono::minutes;
sys_info r{};
r.offset = offset_;
if (start_rule_.ok())
{
auto y = year_month_day{floor<days>(st)}.year();
if (st >= get_next_start(y))
++y;
else if (st < get_prev_end(y))
--y;
auto start = get_start(y);
auto end = get_end(y);
if (start <= end) // (northern hemisphere)
{
if (start <= st && st < end)
{
r.begin = start;
r.end = end;
r.offset += save_;
r.save = ceil<minutes>(save_);
r.abbrev = dst_abbrev_;
}
else if (st < start)
{
r.begin = get_prev_end(y);
r.end = start;
r.abbrev = std_abbrev_;
}
else // st >= end
{
r.begin = end;
r.end = get_next_start(y);
r.abbrev = std_abbrev_;
}
}
else // end < start (southern hemisphere)
{
if (end <= st && st < start)
{
r.begin = end;
r.end = start;
r.abbrev = std_abbrev_;
}
else if (st < end)
{
r.begin = get_prev_start(y);
r.end = end;
r.offset += save_;
r.save = ceil<minutes>(save_);
r.abbrev = dst_abbrev_;
}
else // st >= start
{
r.begin = start;
r.end = get_next_end(y);
r.offset += save_;
r.save = ceil<minutes>(save_);
r.abbrev = dst_abbrev_;
}
}
}
else
r = contant_offset();
assert(r.begin <= st && st < r.end);
return r;
}
template <class Duration>
date::local_info
time_zone::get_info(date::local_time<Duration> tp) const
{
using date::local_info;
using date::year_month_day;
using date::days;
using date::sys_days;
using date::sys_seconds;
using date::year;
using date::ceil;
using date::January;
using date::December;
using date::last;
using std::chrono::seconds;
using std::chrono::minutes;
local_info r{};
using date::floor;
if (start_rule_.ok())
{
auto y = year_month_day{floor<days>(tp)}.year();
auto start = get_start(y);
auto end = get_end(y);
auto utcs = sys_seconds{floor<seconds>(tp - offset_).time_since_epoch()};
auto utcd = sys_seconds{floor<seconds>(tp - (offset_ + save_)).time_since_epoch()};
auto northern = start <= end;
if ((utcs < start) != (utcd < start))
{
if (northern)
r.first.begin = get_prev_end(y);
else
r.first.begin = end;
r.first.end = start;
r.first.offset = offset_;
r.first.abbrev = std_abbrev_;
r.second.begin = start;
if (northern)
r.second.end = end;
else
r.second.end = get_next_end(y);
r.second.abbrev = dst_abbrev_;
r.second.offset = offset_ + save_;
r.second.save = ceil<minutes>(save_);
r.result = save_ > seconds{0} ? local_info::nonexistent
: local_info::ambiguous;
}
else if ((utcs < end) != (utcd < end))
{
if (northern)
r.first.begin = start;
else
r.first.begin = get_prev_start(y);
r.first.end = end;
r.first.offset = offset_ + save_;
r.first.save = ceil<minutes>(save_);
r.first.abbrev = dst_abbrev_;
r.second.begin = end;
if (northern)
r.second.end = get_next_start(y);
else
r.second.end = start;
r.second.abbrev = std_abbrev_;
r.second.offset = offset_;
r.result = save_ > seconds{0} ? local_info::ambiguous
: local_info::nonexistent;
}
else
r.first = get_info(utcs);
}
else
r.first = contant_offset();
return r;
}
template <class Duration>
date::sys_time<typename std::common_type<Duration, std::chrono::seconds>::type>
time_zone::to_sys(date::local_time<Duration> tp) const
{
using date::local_info;
using date::sys_time;
using date::ambiguous_local_time;
using date::nonexistent_local_time;
auto i = get_info(tp);
if (i.result == local_info::nonexistent)
throw nonexistent_local_time(tp, i);
else if (i.result == local_info::ambiguous)
throw ambiguous_local_time(tp, i);
return sys_time<Duration>{tp.time_since_epoch()} - i.first.offset;
}
template <class Duration>
date::sys_time<typename std::common_type<Duration, std::chrono::seconds>::type>
time_zone::to_sys(date::local_time<Duration> tp, date::choose z) const
{
using date::local_info;
using date::sys_time;
using date::choose;
auto i = get_info(tp);
if (i.result == local_info::nonexistent)
{
return i.first.end;
}
else if (i.result == local_info::ambiguous)
{
if (z == choose::latest)
return sys_time<Duration>{tp.time_since_epoch()} - i.second.offset;
}
return sys_time<Duration>{tp.time_since_epoch()} - i.first.offset;
}
template <class Duration>
date::local_time<typename std::common_type<Duration, std::chrono::seconds>::type>
time_zone::to_local(date::sys_time<Duration> tp) const
{
using date::local_time;
using std::chrono::seconds;
using LT = local_time<typename std::common_type<Duration, seconds>::type>;
auto i = get_info(tp);
return LT{(tp + i.offset).time_since_epoch()};
}
inline
std::ostream&
operator<<(std::ostream& os, const time_zone& z)
{
using date::operator<<;
os << '{';
os << z.std_abbrev_ << ", " << z.dst_abbrev_ << date::format(", %T, ", z.offset_)
<< date::format("%T, [", z.save_) << z.start_rule_ << ", " << z.end_rule_ << ")}";
return os;
}
inline
std::string
time_zone::name() const
{
using namespace date;
using namespace std::chrono;
auto print_abbrev = [](std::string const& nm)
{
if (std::any_of(nm.begin(), nm.end(),
[](char c)
{
return !std::isalpha(c);
}))
{
return '<' + nm + '>';
}
return nm;
};
auto print_offset = [](seconds off)
{
std::string nm;
date::hh_mm_ss<seconds> offset{-off};
if (offset.is_negative())
nm += '-';
nm += std::to_string(offset.hours().count());
if (offset.minutes() != minutes{0} || offset.seconds() != seconds{0})
{
nm += ':';
if (offset.minutes() < minutes{10})
nm += '0';
nm += std::to_string(offset.minutes().count());
if (offset.seconds() != seconds{0})
{
nm += ':';
if (offset.seconds() < seconds{10})
nm += '0';
nm += std::to_string(offset.seconds().count());
}
}
return nm;
};
auto nm = print_abbrev(std_abbrev_);
nm += print_offset(offset_);
if (!dst_abbrev_.empty())
{
nm += print_abbrev(dst_abbrev_);
if (save_ != hours{1})
nm += print_offset(offset_+save_);
if (start_rule_.ok())
{
nm += ',';
nm += start_rule_.to_string();
nm += ',';
nm += end_rule_.to_string();
}
}
return nm;
}
inline
bool
operator==(const time_zone& x, const time_zone& y)
{
return x.std_abbrev_ == y.std_abbrev_ &&
x.dst_abbrev_ == y. dst_abbrev_ &&
x.offset_ == y.offset_ &&
x.save_ == y.save_ &&
x.start_rule_ == y.start_rule_ &&
x.end_rule_ == y.end_rule_;
}
inline
bool
operator!=(const time_zone& x, const time_zone& y)
{
return !(x == y);
}
namespace detail
{
inline
void
throw_invalid(const string_t& s, unsigned i, const string_t& message)
{
throw std::runtime_error(std::string("Invalid time_zone initializer.\n") +
std::string(message) + ":\n" +
std::string(s) + '\n' +
"\x1b[1;32m" +
std::string(i, '~') + '^' +
std::string(i < s.size() ? s.size()-i-1 : 0, '~') +
"\x1b[0m");
}
inline
unsigned
read_date(const string_t& s, unsigned i, rule& r)
{
using date::month;
using date::weekday;
if (i == s.size())
throw_invalid(s, i, "Expected rule but found end of string");
if (s[i] == 'J')
{
++i;
unsigned n;
i = read_unsigned(s, i, 3, n, "Expected to find the Julian day [1, 365]");
if (!(1 <= n && n <= 365))
throw_invalid(s, i-1, "Expected Julian day to be in the range [1, 365]");
r.mode_ = rule::J;
r.n_ = n;
}
else if (s[i] == 'M')
{
++i;
unsigned m;
i = read_unsigned(s, i, 2, m, "Expected to find month [1, 12]");
if (!(1 <= m && m <= 12))
throw_invalid(s, i-1, "Expected month to be in the range [1, 12]");
if (i == s.size() || s[i] != '.')
throw_invalid(s, i, "Expected '.' after month");
++i;
unsigned n;
i = read_unsigned(s, i, 1, n, "Expected to find week number [1, 5]");
if (!(1 <= n && n <= 5))
throw_invalid(s, i-1, "Expected week number to be in the range [1, 5]");
if (i == s.size() || s[i] != '.')
throw_invalid(s, i, "Expected '.' after weekday index");
++i;
unsigned wd;
i = read_unsigned(s, i, 1, wd, "Expected to find day of week [0, 6]");
if (wd > 6)
throw_invalid(s, i-1, "Expected day of week to be in the range [0, 6]");
r.mode_ = rule::M;
r.m_ = month{m};
r.wd_ = weekday{wd};
r.n_ = n;
}
else if (std::isdigit(s[i]))
{
unsigned n;
i = read_unsigned(s, i, 3, n);
if (n > 365)
throw_invalid(s, i-1, "Expected Julian day to be in the range [0, 365]");
r.mode_ = rule::N;
r.n_ = n;
}
else
throw_invalid(s, i, "Expected 'J', 'M', or a digit to start rule");
if (i != s.size() && s[i] == '/')
{
++i;
std::chrono::seconds t;
i = read_unsigned_time(s, i, t);
r.time_ = t;
}
return i;
}
inline
unsigned
read_name(const string_t& s, unsigned i, std::string& name)
{
if (i == s.size())
throw_invalid(s, i, "Expected a name but found end of string");
if (s[i] == '<')
{
++i;
while (true)
{
if (i == s.size())
throw_invalid(s, i,
"Expected to find closing '>', but found end of string");
if (s[i] == '>')
break;
name.push_back(s[i]);
++i;
}
++i;
}
else
{
while (i != s.size() && std::isalpha(s[i]))
{
name.push_back(s[i]);
++i;
}
}
return i;
}
inline
unsigned
read_signed_time(const string_t& s, unsigned i,
std::chrono::seconds& t)
{
if (i == s.size())
throw_invalid(s, i, "Expected to read signed time, but found end of string");
bool negative = false;
if (s[i] == '-')
{
negative = true;
++i;
}
else if (s[i] == '+')
++i;
i = read_unsigned_time(s, i, t);
if (negative)
t = -t;
return i;
}
inline
unsigned
read_unsigned_time(const string_t& s, unsigned i, std::chrono::seconds& t)
{
using std::chrono::seconds;
using std::chrono::minutes;
using std::chrono::hours;
if (i == s.size())
throw_invalid(s, i, "Expected to read unsigned time, but found end of string");
unsigned x;
i = read_unsigned(s, i, 2, x, "Expected to find hours [0, 24]");
if (x > 24)
throw_invalid(s, i-1, "Expected hours to be in the range [0, 24]");
t = hours{x};
if (i != s.size() && s[i] == ':')
{
++i;
i = read_unsigned(s, i, 2, x, "Expected to find minutes [0, 59]");
if (x > 59)
throw_invalid(s, i-1, "Expected minutes to be in the range [0, 59]");
t += minutes{x};
if (i != s.size() && s[i] == ':')
{
++i;
i = read_unsigned(s, i, 2, x, "Expected to find seconds [0, 59]");
if (x > 59)
throw_invalid(s, i-1, "Expected seconds to be in the range [0, 59]");
t += seconds{x};
}
}
return i;
}
inline
unsigned
read_unsigned(const string_t& s, unsigned i, unsigned limit, unsigned& u,
const string_t& message)
{
if (i == s.size() || !std::isdigit(s[i]))
throw_invalid(s, i, message);
u = static_cast<unsigned>(s[i] - '0');
unsigned count = 1;
for (++i; count < limit && i != s.size() && std::isdigit(s[i]); ++i, ++count)
u = u * 10 + static_cast<unsigned>(s[i] - '0');
return i;
}
} // namespace detail
} // namespace Posix
namespace date
{
template <>
struct zoned_traits<Posix::time_zone>
{
#if HAS_STRING_VIEW
static
Posix::time_zone
locate_zone(std::string_view name)
{
return Posix::time_zone{name};
}
#else // !HAS_STRING_VIEW
static
Posix::time_zone
locate_zone(const std::string& name)
{
return Posix::time_zone{name};
}
static
Posix::time_zone
locate_zone(const char* name)
{
return Posix::time_zone{name};
}
#endif // !HAS_STRING_VIEW
};
} // namespace date
#endif // PTZ_H