timestamp.hpp

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#ifndef OSMIUM_OSM_TIMESTAMP_HPP
#define OSMIUM_OSM_TIMESTAMP_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 <osmium/util/minmax.hpp> // IWYU pragma: keep
 
#include <array>
#include <cassert>
#include <cstdint>
#include <ctime>
#include <iosfwd>
#include <limits>
#include <stdexcept>
#include <string>
#include <type_traits>
 
namespace osmium {
 
    namespace detail {
 
        inline void add_2digit_int_to_string(int value, std::string& out) {
            assert(value >= 0 && value <= 99);
            if (value > 9) {
                const int dec = value / 10;
                out += static_cast<char>('0' + dec);
                value -= dec * 10;
            } else {
                out += '0';
            }
            out += static_cast<char>('0' + value);
        }
 
        inline void add_4digit_int_to_string(int value, std::string& out) {
            assert(value >= 1000 && value <= 9999);
 
            const int dec1 = value / 1000;
            out += static_cast<char>('0' + dec1);
            value -= dec1 * 1000;
 
            const int dec2 = value / 100;
            out += static_cast<char>('0' + dec2);
            value -= dec2 * 100;
 
            const int dec3 = value / 10;
            out += static_cast<char>('0' + dec3);
            value -= dec3 * 10;
 
            out += static_cast<char>('0' + value);
        }
 
        inline bool fractional_seconds(const char** s) noexcept {
            const char* str = *s;
 
            if (*str != '.' && *str != ',') {
                return false;
            }
 
            ++str;
            if (*str < '0' || *str > '9') {
                return false;
            }
 
            do {
                ++str;
            } while (*str >= '0' && *str <= '9');
 
            *s = str;
            return *str == 'Z';
        }
 
        inline std::time_t parse_timestamp(const char** s) {
            const char* str = *s;
            *s += 19;
 
            static const std::array<int, 12> mon_lengths = {{
                31, 29, 31, 30, 31, 30,
                31, 31, 30, 31, 30, 31
            }};
 
            if (str[ 0] >= '0' && str[ 0] <= '9' &&
                str[ 1] >= '0' && str[ 1] <= '9' &&
                str[ 2] >= '0' && str[ 2] <= '9' &&
                str[ 3] >= '0' && str[ 3] <= '9' &&
                str[ 4] == '-' &&
                str[ 5] >= '0' && str[ 5] <= '9' &&
                str[ 6] >= '0' && str[ 6] <= '9' &&
                str[ 7] == '-' &&
                str[ 8] >= '0' && str[ 8] <= '9' &&
                str[ 9] >= '0' && str[ 9] <= '9' &&
                str[10] == 'T' &&
                str[11] >= '0' && str[11] <= '9' &&
                str[12] >= '0' && str[12] <= '9' &&
                str[13] == ':' &&
                str[14] >= '0' && str[14] <= '9' &&
                str[15] >= '0' && str[15] <= '9' &&
                str[16] == ':' &&
                str[17] >= '0' && str[17] <= '9' &&
                str[18] >= '0' && str[18] <= '9' &&
                (str[19] == 'Z' || fractional_seconds(s))) {
                ++(*s);
                std::tm tm; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init)
                tm.tm_year = (str[ 0] - '0') * 1000 +
                             (str[ 1] - '0') *  100 +
                             (str[ 2] - '0') *   10 +
                             (str[ 3] - '0')        - 1900;
                tm.tm_mon  = (str[ 5] - '0') * 10 + (str[ 6] - '0') - 1;
                tm.tm_mday = (str[ 8] - '0') * 10 + (str[ 9] - '0');
                tm.tm_hour = (str[11] - '0') * 10 + (str[12] - '0');
                tm.tm_min  = (str[14] - '0') * 10 + (str[15] - '0');
                tm.tm_sec  = (str[17] - '0') * 10 + (str[18] - '0');
                tm.tm_wday = 0;
                tm.tm_yday = 0;
                tm.tm_isdst = 0;
                if (tm.tm_year >= 0 &&
                    tm.tm_mon  >= 0 && tm.tm_mon  <= 11 &&
                    tm.tm_mday >= 1 && tm.tm_mday <= mon_lengths[tm.tm_mon] &&
                    tm.tm_hour >= 0 && tm.tm_hour <= 23 &&
                    tm.tm_min  >= 0 && tm.tm_min  <= 59 &&
                    tm.tm_sec  >= 0 && tm.tm_sec  <= 60) {
#ifndef _WIN32
                    return timegm(&tm);
#else
                    return _mkgmtime(&tm);
#endif
                }
            }
            throw std::invalid_argument{std::string{"can not parse timestamp: '"} + str + "'"};
        }
 
        inline std::time_t parse_timestamp(const char* s) {
            const char** str = &s;
            return parse_timestamp(str);
        }
 
    } // namespace detail
 
    class Timestamp {
 
        uint32_t m_timestamp = 0;
 
        void to_iso_str(std::string& s) const {
            std::tm tm; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init)
            const std::time_t sse = seconds_since_epoch();
#ifndef NDEBUG
            auto result =
#endif
#ifndef _WIN32
            gmtime_r(&sse, &tm);
            assert(result != nullptr);
#else
            gmtime_s(&tm, &sse);
            assert(result == 0);
#endif
 
            detail::add_4digit_int_to_string(tm.tm_year + 1900, s);
            s += '-';
            detail::add_2digit_int_to_string(tm.tm_mon + 1, s);
            s += '-';
            detail::add_2digit_int_to_string(tm.tm_mday, s);
            s += 'T';
            detail::add_2digit_int_to_string(tm.tm_hour, s);
            s += ':';
            detail::add_2digit_int_to_string(tm.tm_min, s);
            s += ':';
            detail::add_2digit_int_to_string(tm.tm_sec, s);
            s += 'Z';
        }
 
    public:
 
        constexpr Timestamp() noexcept = default;
 
        template <typename T, typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
        constexpr Timestamp(T timestamp) noexcept : // NOLINT(google-explicit-constructor, hicpp-explicit-conversions)
            m_timestamp(static_cast<uint32_t>(timestamp)) {
        }
 
        explicit Timestamp(const char* timestamp) :
            m_timestamp(static_cast<uint32_t>(detail::parse_timestamp(timestamp))) {
        }
 
        explicit Timestamp(const std::string& timestamp) :
            Timestamp(timestamp.c_str()) {
        }
 
        bool valid() const noexcept {
            return m_timestamp != 0;
        }
 
        explicit constexpr operator bool() const noexcept {
            return m_timestamp != 0;
        }
 
        constexpr std::time_t seconds_since_epoch() const noexcept {
            return static_cast<std::time_t>(m_timestamp);
        }
 
        explicit constexpr operator uint32_t() const noexcept {
            return m_timestamp;
        }
 
        explicit constexpr operator uint64_t() const noexcept {
            return static_cast<uint64_t>(m_timestamp);
        }
 
        template <typename T>
        void operator+=(T time_difference) noexcept {
            m_timestamp += time_difference;
        }
 
        template <typename T>
        void operator-=(T time_difference) noexcept {
            m_timestamp -= time_difference;
        }
 
        std::string to_iso() const {
            std::string s;
 
            if (m_timestamp != 0) {
                to_iso_str(s);
            }
 
            return s;
        }
 
        std::string to_iso_all() const {
            std::string s;
 
            to_iso_str(s);
 
            return s;
        }
 
    }; // class Timestamp
 
    inline constexpr Timestamp start_of_time() noexcept {
        return {1};
    }
 
    inline constexpr Timestamp end_of_time() noexcept {
        return {std::numeric_limits<uint32_t>::max()};
    }
 
    template <typename TChar, typename TTraits>
    inline std::basic_ostream<TChar, TTraits>& operator<<(std::basic_ostream<TChar, TTraits>& out, Timestamp timestamp) {
        out << timestamp.to_iso();
        return out;
    }
 
    inline bool operator==(const Timestamp& lhs, const Timestamp& rhs) noexcept {
        return static_cast<uint32_t>(lhs) == static_cast<uint32_t>(rhs);
    }
 
    inline bool operator!=(const Timestamp& lhs, const Timestamp& rhs) noexcept {
        return !(lhs == rhs);
    }
 
    inline bool operator<(const Timestamp& lhs, const Timestamp& rhs) noexcept {
        return static_cast<uint32_t>(lhs) < static_cast<uint32_t>(rhs);
    }
 
    inline bool operator>(const Timestamp& lhs, const Timestamp& rhs) noexcept {
        return rhs < lhs;
    }
 
    inline bool operator<=(const Timestamp& lhs, const Timestamp& rhs) noexcept {
        return !(rhs < lhs);
    }
 
    inline bool operator>=(const Timestamp& lhs, const Timestamp& rhs) noexcept {
        return !(lhs < rhs);
    }
 
    template <>
    inline osmium::Timestamp min_op_start_value<osmium::Timestamp>() {
        return end_of_time();
    }
 
    template <>
    inline osmium::Timestamp max_op_start_value<osmium::Timestamp>() {
        return start_of_time();
    }
 
} // namespace osmium
 
#endif // OSMIUM_OSM_TIMESTAMP_HPP