#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; }

        friend class tsc_tick_count;

        friend tsc_interval_t operator-(
        const tsc_tick_count t1, const tsc_tick_count t0);
    };

#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 );
}

#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');
}

class timePair
{
    tsc_tick_count KMP_ALIGN_CACHE start;
    tsc_tick_count end;

public:
    timePair() : start(-std::numeric_limits<int64_t>::max()), end(-std::numeric_limits<int64_t>::max()) {}
    tsc_tick_count get_start() const { return start; }
    tsc_tick_count get_end()   const { return end; }
    tsc_tick_count * get_startp()    { return &start; }
    tsc_tick_count * get_endp()      { return &end; }

    void markStart() { start = tsc_tick_count::now(); }
    void markEnd()   { end   = tsc_tick_count::now(); }
    void set_start(tsc_tick_count s) { start = s; }
    void set_end  (tsc_tick_count e) { end = e; }

    tsc_tick_count::tsc_interval_t duration() const { return end-start; }
    std::string format() const;

};

extern tsc_tick_count::tsc_interval_t computeLastInLastOutInterval(timePair * times, int nTimes);
#endif // KMP_STATS_TIMING_H