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#pragma once
/**
* @file
* @brief Strong (because it works) and independent (of contrib/libs/geohash) GeoHash implementation
* GeoHash algo: https://en.wikipedia.org/wiki/Geohash
* Useful links:
* 1. http://geohash.org - Main Site
* 2. https://dou.ua/lenta/articles/geohash - Geohash-based geopoints clusterization
* 3. http://www.movable-type.co.uk/scripts/geohash.html - bidirectional encoding and visualization
*/
#include <library/cpp/geohash/direction.h>
#include <library/cpp/geohash/direction.h_serialized.h>
#include <library/cpp/geo/geo.h>
#include <util/generic/maybe.h>
#include <util/generic/string.h>
#include <util/system/types.h>
#include <array>
namespace NGeoHash {
using TBoundingBoxLL = NGeo::TGeoBoundingBox;
static constexpr auto directionsCount = GetEnumItemsCount<EDirection>();
template <class T>
class TNeighbours: public std::array<T, directionsCount> {
public:
TNeighbours() = default;
TNeighbours(std::initializer_list<T> list) {
Y_ASSERT(list.size() == directionsCount);
std::copy(list.begin(), list.end(), std::array<T, directionsCount>::begin());
}
const T& operator[](EDirection direction) const {
return std::array<T, directionsCount>::operator[](static_cast<size_t>(direction));
}
T& operator[](EDirection direction) {
return std::array<T, directionsCount>::operator[](static_cast<size_t>(direction));
}
};
class TGeoHashDescriptor {
public:
TGeoHashDescriptor() noexcept
: Bits(0)
, Steps(0)
{
}
TGeoHashDescriptor(ui64 bits, ui8 steps) noexcept
: Bits(bits)
, Steps(steps)
{
}
TGeoHashDescriptor(double latitude, double longitude, ui8 steps);
TGeoHashDescriptor(double latitude, double longitude, const TBoundingBoxLL& limits, ui8 steps);
TGeoHashDescriptor(const NGeo::TPointLL& point, ui8 steps);
TGeoHashDescriptor(const NGeo::TPointLL& point, const TBoundingBoxLL& limits, ui8 steps);
explicit TGeoHashDescriptor(const TString& hashString);
ui64 GetBits() const;
ui8 GetSteps() const;
TString ToString() const;
NGeo::TPointLL ToPoint(const TBoundingBoxLL& limits) const;
NGeo::TPointLL ToPoint() const;
TBoundingBoxLL ToBoundingBox(const TBoundingBoxLL& limits) const;
TBoundingBoxLL ToBoundingBox() const;
TMaybe<TGeoHashDescriptor> GetNeighbour(EDirection direction) const;
TNeighbours<TMaybe<TGeoHashDescriptor>> GetNeighbours() const;
TVector<TGeoHashDescriptor> GetChildren(ui8 steps) const;
static ui8 StepsToPrecision(ui8 steps);
static ui8 PrecisionToSteps(ui8 precision);
private:
void InitFromLatLon(double latitude, double longitude, const TBoundingBoxLL& limits, ui8 steps);
std::pair<ui8, ui8> LatLonSteps() const;
std::pair<ui32, ui32> LatLonBits() const;
void SetLatLonBits(ui32 latBits, ui32 lonBits);
static ui64 Interleave64(ui32 x, ui32 y);
static std::pair<ui32, ui32> Deinterleave64(ui64 interleaved);
private:
static const ui8 StepsPerPrecisionUnit = 5;
ui64 Bits;
ui8 Steps;
};
ui64 Encode(double latitude, double longitude, ui8 precision);
ui64 Encode(const NGeo::TPointLL& point, ui8 precision);
TString EncodeToString(double latitude, double longitude, ui8 precision);
TString EncodeToString(const NGeo::TPointLL& point, ui8 precision);
NGeo::TPointLL DecodeToPoint(const TString& hashString);
NGeo::TPointLL DecodeToPoint(ui64 hash, ui8 precision);
TBoundingBoxLL DecodeToBoundingBox(const TString& hashString);
TBoundingBoxLL DecodeToBoundingBox(ui64 hash, ui8 precision);
TMaybe<ui64> GetNeighbour(ui64 hash, EDirection direction, ui8 precision);
TMaybe<TString> GetNeighbour(const TString& hashString, EDirection direction);
using TGeoHashBitsNeighbours = TNeighbours<TMaybe<ui64>>;
using TGeoHashStringNeighbours = TNeighbours<TMaybe<TString>>;
TGeoHashBitsNeighbours GetNeighbours(ui64 hash, ui8 precision);
TGeoHashStringNeighbours GetNeighbours(const TString& hashString);
TVector<TString> GetChildren(const TString& hashString);
} /* namespace NGeoHash */
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