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module routemon:time$impl;
import :time;
export namespace routemon::time {
using timestamp = std::chrono::time_point<std::chrono::utc_clock>;
period::period(timestamp start, timestamp end) : start_{start}, end_{end}
{
if (start >= end)
{
throw std::invalid_argument("period: start should be before end");
}
}
auto period::intersect(period other) const -> std::optional<period>
{
auto const new_start = start_ < other.start() ? other.start() : start_;
auto const new_end = other.end() < end_ ? other.end() : end_;
return new_start < new_end ? std::make_optional(period{new_start, new_end})
: std::nullopt;
}
auto period::except(period other) const
-> std::pair<std::optional<period>, std::optional<period>>
{
auto const before_start = start_;
auto const before_end = other.start();
auto const after_start = end_;
auto const after_end = other.end();
std::optional<period> before, after;
if (before_start < before_end)
before = period{before_start, before_end};
if (after_start < after_end)
after = period{after_end, after_start};
return std::make_pair(before, after);
}
auto period::start() const -> timestamp { return start_; }
auto period::end() const -> timestamp { return end_; }
period_seq::period_seq(std::vector<period> periods)
: periods_{std::move(periods)}
{
for (auto i = 0uz; i < periods_.size(); i++)
{
if (i + 1 < periods_.size())
{
if (periods_[i].end() >= periods_[i + 1].start())
{
throw std::logic_error{"period_seq: vector provided to private "
"constructor not ordered properly"};
}
}
}
}
period_seq::period_seq(period singleton) : periods_{singleton} {}
auto period_seq::intersect(period_seq const& other) const -> period_seq
{
auto it1 = periods_.begin();
auto end1 = periods_.end();
auto it2 = other.periods_.begin();
auto end2 = other.periods_.end();
auto res = std::vector<period>{};
while (it1 != end1 && it2 != end2)
{
auto overlap = it1->intersect(*it2);
if (overlap)
{
res.push_back(*overlap);
if (it1->end() < it2->end())
{
it1++;
}
else
{
it2++;
}
}
else
{
if (it1->end() < it2->start())
{
it1++;
}
else
{
it2++;
}
}
}
return period_seq{res};
}
auto period_seq::except(period_seq const& other) const -> period_seq
{
// This code was pretty tricky to write, I wouldn't be surprised if it
// has some bugs in it.
auto it1 = periods_.begin();
auto end1 = periods_.end();
auto it2 = other.periods_.begin();
auto end2 = other.periods_.end();
auto res = std::vector<period>{};
if (it1 == end1)
return period_seq{res};
if (it2 == end2)
return period_seq{periods_};
auto period1 = period{*it1++};
while (it1 != end1 && it2 != end2)
{
if (period1.end() <= it2->start())
{
res.push_back(period1);
period1 = *it1++;
}
else if (it2->end() <= period1.start())
{
it2++;
}
else /* period1.begin() < it2->end() && it2->begin() <
period1.end() */
{
auto const [mbefore, mafter] = period1.except(*it2);
if (mbefore)
res.push_back(*mbefore);
if (mafter)
{
period1 = *mafter;
}
else
{
period1 = *it1++;
}
}
}
return period_seq{res};
}
auto period_seq::periods() const -> std::vector<period> const&
{
return periods_;
}
auto operator<<(std::ostream& os, period const& p) -> std::ostream&
{
return os << "[" << p.start() << ", " << p.end() << ")";
}
auto operator<<(std::ostream& os, period_seq const& ps) -> std::ostream&
{
os << "{";
auto it = ps.periods().begin();
while (it != ps.periods().end())
{
os << " " << *it;
if (++it != ps.periods().end())
{
os << ",";
}
}
return os << " }";
}
} // namespace routemon::time
|
