#ifndef KMP_STATS_TIMING_H
#define KMP_STATS_TIMING_H

/** @file kmp_stats_timing.h
 * Access to real time clock and timers.
 */


//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.txt for details.
//
//===----------------------------------------------------------------------===//


#include <stdint.h>
#include <string>
#include <limits>
#include "kmp_os.h"
#if KMP_HAVE_X86INTRIN_H
# include <x86intrin.h>
#endif

class tsc_tick_count {
  private:
    int64_t my_count;

  public:
    class tsc_interval_t {
        int64_t value;
        explicit tsc_interval_t(int64_t _value) : value(_value) {}
     public:
        tsc_interval_t() : value(0) {}; // Construct 0 time duration
#if KMP_HAVE_TICK_TIME
        double seconds() const; // Return the length of a time interval in seconds
#endif
        double ticks() const { return double(value); }
        int64_t getValue() const { return value; }
        tsc_interval_t& operator=(int64_t nvalue) { value = nvalue; return *this; }

        friend class tsc_tick_count;

        friend tsc_interval_t operator-(const tsc_tick_count& t1,
                                        const tsc_tick_count& t0);
        friend tsc_interval_t operator-(const tsc_tick_count::tsc_interval_t& i1,
                                        const tsc_tick_count::tsc_interval_t& i0);
        friend tsc_interval_t& operator+=(tsc_tick_count::tsc_interval_t& i1,
                                         const tsc_tick_count::tsc_interval_t& i0);
    };

#if KMP_HAVE___BUILTIN_READCYCLECOUNTER
    tsc_tick_count() : my_count(static_cast<int64_t>(__builtin_readcyclecounter())) {}
#elif KMP_HAVE___RDTSC
    tsc_tick_count() : my_count(static_cast<int64_t>(__rdtsc())) {};
#else
# error Must have high resolution timer defined
#endif
    tsc_tick_count(int64_t value) : my_count(value) {};
    int64_t getValue() const { return my_count; }
    tsc_tick_count later (tsc_tick_count const other) const {
        return my_count > other.my_count ? (*this) : other;
    }
    tsc_tick_count earlier(tsc_tick_count const other) const {
        return my_count < other.my_count ? (*this) : other;
    }
#if KMP_HAVE_TICK_TIME
    static double tick_time(); // returns seconds per cycle (period) of clock
#endif
    static tsc_tick_count now() { return tsc_tick_count(); } // returns the rdtsc register value
    friend tsc_tick_count::tsc_interval_t operator-(const tsc_tick_count& t1, const tsc_tick_count& t0);
};

inline tsc_tick_count::tsc_interval_t operator-(const tsc_tick_count& t1, const tsc_tick_count& t0)
{
    return tsc_tick_count::tsc_interval_t( t1.my_count-t0.my_count );
}

inline tsc_tick_count::tsc_interval_t operator-(const tsc_tick_count::tsc_interval_t& i1, const tsc_tick_count::tsc_interval_t& i0)
{
    return tsc_tick_count::tsc_interval_t( i1.value-i0.value );
}

inline tsc_tick_count::tsc_interval_t& operator+=(tsc_tick_count::tsc_interval_t& i1, const tsc_tick_count::tsc_interval_t& i0)
{
    i1.value += i0.value;
    return i1;
}

#if KMP_HAVE_TICK_TIME
inline double tsc_tick_count::tsc_interval_t::seconds() const
{
    return value*tick_time();
}
#endif

extern std::string formatSI(double interval, int width, char unit);

inline std::string formatSeconds(double interval, int width)
{
    return formatSI(interval, width, 'S');
}

inline std::string formatTicks(double interval, int width)
{
    return formatSI(interval, width, 'T');
}

#endif // KMP_STATS_TIMING_H