295 lines
9.6 KiB
C++
295 lines
9.6 KiB
C++
/*
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* Copyright (C) 2015 Cloudius Systems, Ltd.
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*/
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#pragma once
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#include <experimental/optional>
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#include <iostream>
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// A range which can have inclusive, exclusive or open-ended bounds on each end.
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template<typename T>
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class range {
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template <typename U>
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using optional = std::experimental::optional<U>;
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public:
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class bound {
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T _value;
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bool _inclusive;
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public:
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bound(T value, bool inclusive = true)
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: _value(std::move(value))
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, _inclusive(inclusive)
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{ }
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const T& value() const & { return _value; }
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T&& value() && { return std::move(_value); }
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bool is_inclusive() const { return _inclusive; }
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bool operator==(const bound& other) const {
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return (_value == other._value) && (_inclusive == other._inclusive);
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}
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};
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private:
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optional<bound> _start;
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optional<bound> _end;
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bool _singular;
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public:
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range(optional<bound> start, optional<bound> end, bool singular = false)
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: _start(std::move(start))
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, _end(std::move(end))
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, _singular(singular)
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{ }
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range(T value)
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: _start(bound(std::move(value), true))
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, _end()
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, _singular(true)
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{ }
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range() : range({}, {}) {}
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public:
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// the point is before the range (works only for non wrapped ranges)
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// Comparator must define a total ordering on T.
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template<typename Comparator>
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bool before(const T& point, Comparator&& cmp) const {
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assert(!is_wrap_around(cmp));
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if (!start()) {
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return false; //open start, no points before
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}
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auto r = cmp(point, start()->value());
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if (r < 0) {
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return true;
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}
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if (!start()->is_inclusive() && r == 0) {
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return true;
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}
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return false;
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}
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// the point is after the range (works only for non wrapped ranges)
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// Comparator must define a total ordering on T.
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template<typename Comparator>
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bool after(const T& point, Comparator&& cmp) const {
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assert(!is_wrap_around(cmp));
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if (!end()) {
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return false; //open end, no points after
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}
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auto r = cmp(end()->value(), point);
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if (r < 0) {
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return true;
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}
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if (!end()->is_inclusive() && r == 0) {
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return true;
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}
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return false;
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}
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static range make(bound start, bound end) {
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return range({std::move(start)}, {std::move(end)});
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}
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static range make_open_ended_both_sides() {
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return {{}, {}};
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}
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static range make_singular(T value) {
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return {std::move(value)};
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}
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static range make_starting_with(bound b) {
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return {{std::move(b)}, {}};
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}
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static range make_ending_with(bound b) {
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return {{}, {std::move(b)}};
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}
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bool is_singular() const {
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return _singular;
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}
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bool is_full() const {
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return !_start && !_end;
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}
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void reverse() {
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if (!_singular) {
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std::swap(_start, _end);
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}
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}
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const optional<bound>& start() const {
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return _start;
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}
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const optional<bound>& end() const {
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return _singular ? _start : _end;
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}
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// Range is a wrap around if end value is smaller than the start value
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// or they're equal and at least one bound is not inclusive.
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// Comparator must define a total ordering on T.
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template<typename Comparator>
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bool is_wrap_around(Comparator&& cmp) const {
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if (_end && _start) {
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auto r = cmp(end()->value(), start()->value());
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return r < 0
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|| (r == 0 && (!start()->is_inclusive() || !end()->is_inclusive()));
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} else {
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return false; // open ended range or singular range don't wrap around
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}
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}
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// Converts a wrap-around range to two non-wrap-around ranges.
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// Call only when is_wrap_around().
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std::pair<range, range> unwrap() const {
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return {
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{ start(), {} },
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{ {}, end() }
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};
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}
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// the point is inside the range
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// Comparator must define a total ordering on T.
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template<typename Comparator>
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bool contains(const T& point, Comparator&& cmp) const {
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if (is_wrap_around(cmp)) {
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auto unwrapped = unwrap();
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return unwrapped.first.contains(point, cmp)
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|| unwrapped.second.contains(point, cmp);
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} else {
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return !before(point, cmp) && !after(point, cmp);
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}
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}
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// split range in two around a split_point. split_point has to be inside the range
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// split_point will belong to first range
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// Comparator must define a total ordering on T.
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template<typename Comparator>
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std::pair<range<T>, range<T>> split(const T& split_point, Comparator&& cmp) const {
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assert(contains(split_point, std::forward<Comparator>(cmp)));
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range left(start(), bound(split_point));
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range right(bound(split_point, false), end());
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return std::make_pair(std::move(left), std::move(right));
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}
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// Create a sub-range including values greater than the split_point. split_point has to be inside the range
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// Comparator must define a total ordering on T.
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template<typename Comparator>
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range<T> split_after(const T& split_point, Comparator&& cmp) const {
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assert(contains(split_point, std::forward<Comparator>(cmp)));
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return range(bound(split_point, false), end());
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}
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// Transforms this range into a new range of a different value type
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// Supplied transformer should transform value of type T (the old type) into value of type U (the new type).
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template<typename U, typename Transformer>
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range<U> transform(Transformer&& transformer) && {
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auto t = [&transformer] (std::experimental::optional<bound>&& b)
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-> std::experimental::optional<typename range<U>::bound>
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{
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if (!b) {
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return {};
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}
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return { { transformer(std::move(*b).value()), b->is_inclusive() } };
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};
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return range<U>(t(std::move(_start)), t(std::move(_end)), _singular);
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}
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private:
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template<typename U>
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static auto serialized_size(U& t) -> decltype(t.serialized_size()) {
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return t.serialized_size();
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}
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template<typename U>
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static auto serialized_size(U& t) -> decltype(t.representation().size()) {
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return t.representation().size() + serialize_int32_size;
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}
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template<typename U>
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static auto serialize(bytes::iterator& out, const U& t) -> decltype(t.serialize(out)) {
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return t.serialize(out);
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}
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template<typename U>
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static auto serialize(bytes::iterator& out, const U& t) -> decltype(t.representation(), void()) {
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auto v = t.representation();
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serialize_int32(out, v.size());
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out = std::copy(v.begin(), v.end(), out);
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}
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template<typename U>
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static auto deserialize_type(bytes_view& in) -> decltype(U::deserialize(in)) {
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return U::deserialize(in);
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}
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template<typename U>
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static auto deserialize_type(bytes_view& in) -> decltype(U::from_bytes(bytes())) {
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bytes v;
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uint32_t size = read_simple<uint32_t>(in);
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return U::from_bytes(to_bytes(read_simple_bytes(in, size)));
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}
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public:
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size_t serialized_size() const {
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auto bound_size = [this] (const optional<bound>& b) {
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size_t size = serialize_bool_size; // if optional is armed
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if (b) {
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size += serialized_size(b.value().value());
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size += serialize_bool_size; // _inclusive
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}
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return size;
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};
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return serialize_bool_size // singular
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+ bound_size(_start) + bound_size(_end);
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}
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void serialize(bytes::iterator& out) const {
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auto serialize_bound = [this] (bytes::iterator& out, const optional<bound>& b) {
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if (b) {
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serialize_bool(out, true);
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serialize(out, b.value().value());
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serialize_bool(out, b.value().is_inclusive());
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} else {
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serialize_bool(out, false);
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}
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};
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serialize_bound(out, _start);
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serialize_bound(out, _end);
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serialize_bool(out, is_singular());
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}
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static range deserialize(bytes_view& in) {
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auto deserialize_bound = [](bytes_view& in) {
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optional<bound> b;
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bool armed = read_simple<bool>(in);
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if (!armed) {
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return b;
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} else {
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T t = deserialize_type<T>(in);
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bool inc = read_simple<bool>(in);
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b.emplace(std::move(t), inc);
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}
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return b;
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};
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auto s = deserialize_bound(in);
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auto e = deserialize_bound(in);
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bool singular = read_simple<bool>(in);
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return range(std::move(s), std::move(e), singular);
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}
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bool operator==(const range& other) const {
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return (_start == other._start) && (_end == other._end) && (_singular == other._singular);
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}
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template<typename U>
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friend std::ostream& operator<<(std::ostream& out, const range<U>& r);
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};
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template<typename U>
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std::ostream& operator<<(std::ostream& out, const range<U>& r) {
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if (r.is_singular()) {
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return out << "==" << r.start()->value();
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}
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if (!r.start()) {
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out << "(-inf, ";
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} else {
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if (r.start()->is_inclusive()) {
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out << "[";
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} else {
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out << "(";
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}
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out << r.start()->value() << ", ";
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}
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if (!r.end()) {
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out << "+inf)";
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} else {
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out << r.end()->value();
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if (r.end()->is_inclusive()) {
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out << "]";
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} else {
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out << ")";
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}
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}
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return out;
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}
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