Interval.h

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/*
 * Developed for the LSST Data Management System.
 * This product includes software developed by the LSST Project
 * (https://www.lsst.org).
 * See the COPYRIGHT file at the top-level directory of this distribution
 * for details of code ownership.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#ifndef LSST_GEOM_INTERVAL_H
#define LSST_GEOM_INTERVAL_H

#include <vector>

#include "ndarray.h"

#include "lsst/geom/Point.h"
#include "lsst/geom/Extent.h"

namespace lsst {
namespace geom {

class IntervalD;

class IntervalI final {
public:
    using Element = int;

    enum class EdgeHandlingEnum {
        EXPAND,
        SHRINK
    };

    IntervalI() noexcept : _min(0), _size(0) {}

    template <typename Iter>
    static IntervalI fromSpannedPoints(Iter first, Iter last) {
        IntervalI result;
        for (auto i = first; i != last; ++i) {
            result = result.expandedTo(*i);
        }
        return result;
    }


    static IntervalI fromSpannedPoints(std::vector<Element> const& elements) {
        return fromSpannedPoints(elements.begin(), elements.end());
    }
    static IntervalI fromSpannedPoints(ndarray::Array<Element const, 1> const& elements) {
        return fromSpannedPoints(elements.begin(), elements.end());
    }

    static IntervalI fromMinMax(Element min, Element max);

    static IntervalI fromMinSize(Element min, Element size);

    static IntervalI fromMaxSize(Element max, Element size);

    static IntervalI fromCenterSize(double center, Element size);

    explicit IntervalI(IntervalD const& other, EdgeHandlingEnum edgeHandling = EdgeHandlingEnum::EXPAND);

    IntervalI(IntervalI const&) noexcept = default;

    IntervalI(IntervalI&&) noexcept = default;

    ~IntervalI() noexcept = default;

    void swap(IntervalI& other) noexcept {
        using std::swap;
        swap(_size, other._size);
        swap(_min, other._min);
    }

    IntervalI& operator=(IntervalI const&) noexcept = default;

    IntervalI& operator=(IntervalI&&) noexcept = default;

    Element getMin() const noexcept { return _min; }
    Element getMax() const noexcept { return _min + _size - 1; }

    Element getBegin() const noexcept { return _min; }
    Element getEnd() const noexcept { return _min + _size; }

    Element getSize() const noexcept { return _size; }

    ndarray::View<boost::fusion::vector1<ndarray::index::Range> > getSlice() const;

    bool isEmpty() const noexcept { return _size == 0; }

    bool contains(Element point) const noexcept;

    bool contains(IntervalI const& other) const noexcept;


    bool overlaps(IntervalI const& other) const noexcept;
    bool intersects(IntervalI const& other) const noexcept { return overlaps(other); }

    bool isDisjointFrom(IntervalI const& other) const noexcept;

    IntervalI dilatedBy(Element buffer) const;

    IntervalI erodedBy(Element buffer) const { return dilatedBy(-buffer); }

    IntervalI shiftedBy(Element offset) const;

    IntervalI reflectedAbout(Element point) const;


    IntervalI expandedTo(Element other) const;
    IntervalI expandedTo(IntervalI const& other) const;

    IntervalI clippedTo(IntervalI const& other) const noexcept;

    bool operator==(IntervalI const& other) const noexcept;

    bool operator!=(IntervalI const& other) const noexcept;

    std::size_t hash_value() const noexcept;

    std::string toString() const;

private:
    template <typename T>
    static IntervalI _fromMinMaxChecked(T min, T max);

    IntervalI(Element min, Element max);

    /*
     *  IntervalI internally stores its minimum point and size, because we
     *  expect these will be the most commonly accessed quantities.
     *
     *  We set the minimum point to the origin for an empty interval, and
     *  use -1 for the maximum point in that case, but this is an internal
     *  detail - all the API guarantees is that for an empty interval,
     *  size == 0.
     */

    Element _min;
    Element _size;
};

class IntervalD final {
public:
    using Element = double;

    IntervalD() noexcept;

    template <typename Iter>
    static IntervalD fromSpannedPoints(Iter first, Iter last) {
        IntervalD result;
        for (auto i = first; i != last; ++i) {
            result = result.expandedTo(*i);
        }
        return result;
    }


    static IntervalD fromSpannedPoints(std::vector<Element> const& elements) {
        return fromSpannedPoints(elements.begin(), elements.end());
    }
    static IntervalD fromSpannedPoints(ndarray::Array<Element const, 1> const& elements) {
        return fromSpannedPoints(elements.begin(), elements.end());
    }

    static IntervalD fromMinMax(Element min, Element max);

    static IntervalD fromMinSize(Element min, Element size);

    static IntervalD fromMaxSize(Element max, Element size);

    static IntervalD fromCenterSize(double center, Element size);

    explicit IntervalD(IntervalI const& other) noexcept;

    IntervalD(IntervalD const&) noexcept = default;

    IntervalD(IntervalD&&) noexcept = default;

    ~IntervalD() noexcept = default;

    void swap(IntervalD& other) noexcept {
        std::swap(_min, other._min);
        std::swap(_max, other._max);
    }

    IntervalD& operator=(IntervalD const&) noexcept = default;

    IntervalD& operator=(IntervalD&&) noexcept = default;

    Element getMin() const noexcept { return _min; }
    Element getMax() const noexcept { return _max; }

    Element getSize() const noexcept;

    Element getCenter() const noexcept;

    bool isEmpty() const noexcept { return std::isnan(_min); }

    bool isFinite() const noexcept { return std::isfinite(getSize()); }

    bool contains(Element point) const;

    bool contains(IntervalD const& other) const noexcept;


    bool overlaps(IntervalD const& other) const noexcept;
    bool intersects(IntervalD const& other) const noexcept { return overlaps(other); }

    bool isDisjointFrom(IntervalD const& other) const noexcept;

    IntervalD dilatedBy(Element buffer) const;

    IntervalD erodedBy(Element buffer) const { return dilatedBy(-buffer); }

    IntervalD shiftedBy(Element offset) const;

    IntervalD reflectedAbout(Element point) const;

    IntervalD expandedTo(Element other) const;

    IntervalD expandedTo(IntervalD const& other) const noexcept;

    IntervalD clippedTo(IntervalD const& other) const noexcept;

    bool operator==(IntervalD const& other) const noexcept;

    bool operator!=(IntervalD const& other) const noexcept;

    std::size_t hash_value() const noexcept;

    std::string toString() const;

private:
    IntervalD(Element min, Element max);

    Element _min;
    Element _max;
};

std::ostream& operator<<(std::ostream& os, IntervalI const& interval);

std::ostream& operator<<(std::ostream& os, IntervalD const& interval);

inline void swap(IntervalI& a, IntervalI& b) noexcept { a.swap(b); }

inline void swap(IntervalD& a, IntervalD& b) noexcept { a.swap(b); }

}  // namespace geom
}  // namespace lsst

namespace std {

template <>
inline void swap<lsst::geom::IntervalI>(lsst::geom::IntervalI& a, lsst::geom::IntervalI& b) noexcept {
    a.swap(b);
}

template <>
inline void swap<lsst::geom::IntervalD>(lsst::geom::IntervalD& a, lsst::geom::IntervalD& b) noexcept {
    a.swap(b);
}

template <>
struct hash<lsst::geom::IntervalI> {
    using argument_type = lsst::geom::IntervalI;
    using result_type = size_t;
    size_t operator()(argument_type const& x) const noexcept { return x.hash_value(); }
};

template <>
struct hash<lsst::geom::IntervalD> {
    using argument_type = lsst::geom::IntervalD;
    using result_type = size_t;
    size_t operator()(argument_type const& x) const noexcept { return x.hash_value(); }
};

}  // namespace std

#endif