timestamp

/*
Copyright (C) 2018-2024 Geoffrey Daniels. https://gpdaniels.com/

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, version 3 of the License only.

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/>.
*/

#pragma once
#ifndef GTL_PLATFORM_TIMESTAMP_HPP
#define GTL_PLATFORM_TIMESTAMP_HPP

// Summary: Function to get a monotonically increasing timestamp.

#if ((defined(linux) || defined(__linux) || defined(__linux__)) || (__APPLE__))
    #include <ctime>
#endif

#if (defined(_WIN32) || defined(_WIN64))
    #if (defined(__amd64__) || defined(__amd64) || defined(__x86_64__) || defined(__x86_64) || defined(_M_X64) || defined(_M_AMD64))
        #define _AMD64_
    #elif (defined(i386) || defined(__i386) || defined(__i386__) || defined(__i386__) || defined(_M_IX86))
        #define _X86_
    #elif (defined(__arm__) || defined(_M_ARM) || defined(_M_ARMT))
        #define _ARM_
    #endif

    #pragma warning(push, 0)

    #include <realtimeapiset.h>
    #pragma comment( lib, "mincore.lib" )

    #pragma warning(pop)
#endif

namespace gtl {
    /// @brief   Get a timestamp representing now.
    /// @return  A representation of the time now using a monotonically increasing clock.
    /// @note    The clock will continue incrementing when the computer is sleeping.
    /// @warning The timestamp epoch is not related to the unix epoch.
    inline long long int timestamp();
    inline long long int timestamp() {
        #if (defined(linux) || defined(__linux) || defined(__linux__))
            struct timespec ts;
            int return_code = clock_gettime(CLOCK_BOOTTIME, &ts);
            if (return_code != 0) {
                return 0;
            }
            return (1000000000ll * static_cast<long long int>(ts.tv_sec) + static_cast<long long int>(ts.tv_nsec));
        #elif (defined(_WIN32) || defined(_WIN64))
            unsigned long long int centinanoseconds;
            QueryInterruptTimePrecise(&centinanoseconds);
            return static_cast<long long int>(centinanoseconds) * 100ll;
        #elif (defined(__APPLE__))
            return static_cast<long long int>(clock_gettime_nsec_np(CLOCK_MONOTONIC_RAW));
        #else
            #error "Failed to define timestamp function."
        #endif
    }
}

#endif // GTL_PLATFORM_TIMESTAMP_HPP