location.hpp

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#ifndef OSMIUM_OSM_LOCATION_HPP
#define OSMIUM_OSM_LOCATION_HPP
 
/*
 
This file is part of Osmium (https://osmcode.org/libosmium).
 
Copyright 2013-2023 Jochen Topf <jochen@topf.org> and others (see README).
 
Boost Software License - Version 1.0 - August 17th, 2003
 
Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
this license (the "Software") to use, reproduce, display, distribute,
execute, and transmit the Software, and to prepare derivative works of the
Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:
 
The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.
 
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, TITLE AND NON-INFRINGEMENT. IN NO EVENT
SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
 
*/
 
#include <algorithm>
#include <cmath>
#include <cstdint>
#include <cstring>
#include <functional>
#include <iosfwd>
#include <iterator>
#include <limits>
#include <stdexcept>
#include <string>
 
namespace osmium {
 
    struct invalid_location : public std::range_error {
 
        explicit invalid_location(const std::string& what) :
            std::range_error(what) {
        }
 
        explicit invalid_location(const char* what) :
            std::range_error(what) {
        }
 
    }; // struct invalid_location
 
    namespace detail {
 
        enum {
            coordinate_precision = 10000000
        };
 
        // Convert string with a floating point number into integer suitable
        // for use as coordinate in a Location.
        inline int32_t string_to_location_coordinate(const char** data) {
            const char* str = *data;
            const char* full = str;
 
            int64_t result = 0;
            int sign = 1;
 
            // one more than significant digits to allow rounding
            int64_t scale = 8;
 
            // paranoia check for maximum number of digits
            int max_digits = 10;
 
            // optional minus sign
            if (*str == '-') {
                sign = -1;
                ++str;
            }
 
            if (*str != '.') {
                // there has to be at least one digit
                if (*str >= '0' && *str <= '9') {
                    result = *str - '0';
                    ++str;
                } else {
                    throw invalid_location{std::string{"wrong format for coordinate: '"} + full + "'"};
                }
 
                // optional additional digits before decimal point
                while (*str >= '0' && *str <= '9' && max_digits > 0) {
                    result = result * 10 + (*str - '0');
                    ++str;
                    --max_digits;
                }
 
                if (max_digits == 0) {
                    throw invalid_location{std::string{"wrong format for coordinate: '"} + full + "'"};
                }
            } else {
                // need at least one digit after decimal dot if there was no
                // digit before decimal dot
                if (*(str + 1) < '0' || *(str + 1) > '9') {
                    throw invalid_location{std::string{"wrong format for coordinate: '"} + full + "'"};
                }
            }
 
            // optional decimal point
            if (*str == '.') {
                ++str;
 
                // read significant digits
                for (; scale > 0 && *str >= '0' && *str <= '9'; --scale, ++str) {
                    result = result * 10 + (*str - '0');
                }
 
                // ignore non-significant digits
                max_digits = 20;
                while (*str >= '0' && *str <= '9' && max_digits > 0) {
                    ++str;
                    --max_digits;
                }
 
                if (max_digits == 0) {
                    throw invalid_location{std::string{"wrong format for coordinate: '"} + full + "'"};
                }
            }
 
            // optional exponent in scientific notation
            if (*str == 'e' || *str == 'E') {
                ++str;
 
                int esign = 1;
                // optional minus sign
                if (*str == '-') {
                    esign = -1;
                    ++str;
                }
 
                int64_t eresult = 0;
 
                // there has to be at least one digit in exponent
                if (*str >= '0' && *str <= '9') {
                    eresult = *str - '0';
                    ++str;
                } else {
                    throw invalid_location{std::string{"wrong format for coordinate: '"} + full + "'"};
                }
 
                // optional additional digits in exponent
                max_digits = 5;
                while (*str >= '0' && *str <= '9' && max_digits > 0) {
                    eresult = eresult * 10 + (*str - '0');
                    ++str;
                    --max_digits;
                }
 
                if (max_digits == 0) {
                    throw invalid_location{std::string{"wrong format for coordinate: '"} + full + "'"};
                }
 
                scale += eresult * esign;
            }
 
            if (scale < 0) {
                for (; scale < 0 && result > 0; ++scale) {
                    result /= 10;
                }
            } else {
                for (; scale > 0; --scale) {
                    result *= 10;
                }
            }
 
            result = (result + 5) / 10 * sign;
 
            if (result > std::numeric_limits<int32_t>::max() ||
                result < std::numeric_limits<int32_t>::min()) {
                throw invalid_location{std::string{"wrong format for coordinate: '"} + full + "'"};
            }
 
            *data = str;
            return static_cast<int32_t>(result);
        }
 
        // Convert integer as used by location for coordinates into a string.
        template <typename T>
        inline T append_location_coordinate_to_string(T iterator, int32_t value) {
            // need to special-case this, because later `value = -value` would overflow.
            if (value == std::numeric_limits<int32_t>::min()) {
                static const char minresult[] = "-214.7483648";
                return std::copy_n(minresult, sizeof(minresult) - 1, iterator);
            }
 
            // handle negative values
            if (value < 0) {
                *iterator++ = '-';
                value = -value;
            }
 
            // write digits into temporary buffer
            int32_t v = value;
            char temp[10];
            char* t = temp;
            do {
                *t++ = static_cast<char>(v % 10) + '0'; // NOLINT(bugprone-narrowing-conversions, cppcoreguidelines-narrowing-conversions)
                v /= 10;
            } while (v != 0);
 
            while (t - temp < 7) {
                *t++ = '0';
            }
 
            // write out digits before decimal point
            if (value >= coordinate_precision) {
                if (value >= 10 * coordinate_precision) {
                    if (value >= 100 * coordinate_precision) {
                        *iterator++ = *--t;
                    }
                    *iterator++ = *--t;
                }
                *iterator++ = *--t;
            } else {
                *iterator++ = '0';
            }
 
            // remove trailing zeros
            const char* tn = temp;
            while (tn < t && *tn == '0') {
                ++tn;
            }
 
            // decimal point
            if (t != tn) {
                *iterator++ = '.';
                while (t != tn) {
                    *iterator++ = *--t;
                }
            }
 
            return iterator;
        }
 
    } // namespace detail
 
    class Location {
 
        int32_t m_x; // NOLINT(modernize-use-default-member-init)
        int32_t m_y; // NOLINT(modernize-use-default-member-init)
 
        constexpr static double precision() noexcept {
            return static_cast<double>(detail::coordinate_precision);
        }
 
    public:
 
        // this value is used for a coordinate to mark it as undefined
        // MSVC doesn't declare std::numeric_limits<int32_t>::max() as
        // constexpr, so we hard code this for the time being.
        // undefined_coordinate = std::numeric_limits<int32_t>::max();
        enum {
            undefined_coordinate = 2147483647
        };
 
        static int32_t double_to_fix(const double c) noexcept {
            return static_cast<int32_t>(std::round(c * precision()));
        }
 
        static constexpr double fix_to_double(const int32_t c) noexcept {
            return static_cast<double>(c) / precision();
        }
 
        explicit constexpr Location() noexcept :
            m_x(undefined_coordinate),
            m_y(undefined_coordinate) {
        }
 
        constexpr Location(const int32_t x, const int32_t y) noexcept :
            m_x(x),
            m_y(y) {
        }
 
        constexpr Location(const int64_t x, const int64_t y) noexcept :
            m_x(static_cast<int32_t>(x)),
            m_y(static_cast<int32_t>(y)) {
        }
 
        Location(const double lon, const double lat) :
            m_x(double_to_fix(lon)),
            m_y(double_to_fix(lat)) {
        }
 
        explicit constexpr operator bool() const noexcept {
            return m_x != undefined_coordinate && m_y != undefined_coordinate;
        }
 
        constexpr bool valid() const noexcept {
            return m_x >= -180 * precision()
                && m_x <=  180 * precision()
                && m_y >=  -90 * precision()
                && m_y <=   90 * precision();
        }
 
        constexpr bool is_defined() const noexcept {
            return m_x != undefined_coordinate || m_y != undefined_coordinate;
        }
 
        constexpr bool is_undefined() const noexcept {
            return m_x == undefined_coordinate && m_y == undefined_coordinate;
        }
 
        constexpr int32_t x() const noexcept {
            return m_x;
        }
 
        constexpr int32_t y() const noexcept {
            return m_y;
        }
 
        Location& set_x(const int32_t x) noexcept {
            m_x = x;
            return *this;
        }
 
        Location& set_y(const int32_t y) noexcept {
            m_y = y;
            return *this;
        }
 
        double lon() const {
            if (!valid()) {
                throw osmium::invalid_location{"invalid location"};
            }
            return fix_to_double(m_x);
        }
 
        double lon_without_check() const noexcept {
            return fix_to_double(m_x);
        }
 
        double lat() const {
            if (!valid()) {
                throw osmium::invalid_location{"invalid location"};
            }
            return fix_to_double(m_y);
        }
 
        double lat_without_check() const noexcept {
            return fix_to_double(m_y);
        }
 
        Location& set_lon(double lon) noexcept {
            m_x = double_to_fix(lon);
            return *this;
        }
 
        Location& set_lat(double lat) noexcept {
            m_y = double_to_fix(lat);
            return *this;
        }
 
        Location& set_lon(const char* str) {
            const char** data = &str;
            const auto value = detail::string_to_location_coordinate(data);
            if (**data != '\0') {
                throw invalid_location{std::string{"characters after coordinate: '"} + *data + "'"};
            }
            m_x = value;
            return *this;
        }
 
        Location& set_lat(const char* str) {
            const char** data = &str;
            const auto value = detail::string_to_location_coordinate(data);
            if (**data != '\0') {
                throw invalid_location{std::string{"characters after coordinate: '"} + *data + "'"};
            }
            m_y = value;
            return *this;
        }
 
        Location& set_lon_partial(const char** str) {
            m_x = detail::string_to_location_coordinate(str);
            return *this;
        }
 
        Location& set_lat_partial(const char** str) {
            m_y = detail::string_to_location_coordinate(str);
            return *this;
        }
 
        template <typename T>
        T as_string_without_check(T iterator, const char separator = ',') const {
            iterator = detail::append_location_coordinate_to_string(iterator, x());
            *iterator++ = separator;
            return detail::append_location_coordinate_to_string(iterator, y());
        }
 
        template <typename T>
        T as_string(T iterator, const char separator = ',') const {
            if (!valid()) {
                throw osmium::invalid_location{"invalid location"};
            }
            return as_string_without_check(iterator, separator);
        }
 
    }; // class Location
 
    inline constexpr bool operator==(const Location& lhs, const Location& rhs) noexcept {
        return lhs.x() == rhs.x() && lhs.y() == rhs.y();
    }
 
    inline constexpr bool operator!=(const Location& lhs, const Location& rhs) noexcept {
        return !(lhs == rhs);
    }
 
    inline constexpr bool operator<(const Location& lhs, const Location& rhs) noexcept {
        return (lhs.x() == rhs.x() && lhs.y() < rhs.y()) || lhs.x() < rhs.x();
    }
 
    inline constexpr bool operator>(const Location& lhs, const Location& rhs) noexcept {
        return rhs < lhs;
    }
 
    inline constexpr bool operator<=(const Location& lhs, const Location& rhs) noexcept {
        return !(rhs < lhs);
    }
 
    inline constexpr bool operator>=(const Location& lhs, const Location& rhs) noexcept {
        return !(lhs < rhs);
    }
 
    template <typename TChar, typename TTraits>
    inline std::basic_ostream<TChar, TTraits>& operator<<(std::basic_ostream<TChar, TTraits>& out, const osmium::Location& location) {
        if (location) {
            out << '(';
            location.as_string(std::ostream_iterator<char>(out), ',');
            out << ')';
        } else {
            out << "(undefined,undefined)";
        }
        return out;
    }
 
    namespace detail {
 
        template <int N>
        inline size_t hash(const osmium::Location& location) noexcept {
            return static_cast<uint32_t>(location.x()) ^ static_cast<uint32_t>(location.y());
        }
 
        template <>
        inline size_t hash<8>(const osmium::Location& location) noexcept {
            uint64_t h = location.x();
            h <<= 32U;
            return static_cast<size_t>(h ^ static_cast<uint64_t>(location.y()));
        }
 
    } // namespace detail
 
} // namespace osmium
 
namespace std {
 
// This pragma is a workaround for a bug in an old libc implementation
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmismatched-tags"
#endif
    template <>
    struct hash<osmium::Location> {
        using argument_type = osmium::Location;
        using result_type = size_t;
        size_t operator()(const osmium::Location& location) const noexcept {
            return osmium::detail::hash<sizeof(size_t)>(location);
        }
    };
#ifdef __clang__
#pragma clang diagnostic pop
#endif
 
} // namespace std
 
#endif // OSMIUM_OSM_LOCATION_HPP