// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; indent-tabs-mode: nil; -*-
//
// Timer.cpp: Rcpp R/C++ interface class library -- Rcpp benchmark utility
//
// Copyright (C) 2012 JJ Allaire, Dirk Eddelbuettel and Romain Francois
//
// This file is part of Rcpp.
//
// Rcpp 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, either version 2 of the License, or
// (at your option) any later version.
//
// Rcpp 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 Rcpp.  If not, see <http://www.gnu.org/licenses/>.

#include <Rcpp.h>
#include <Rcpp/Benchmark/Timer.h>

#if defined(_WIN32) 
    #define WIN32_LEAN_AND_MEAN
    #include <windows.h>
#elif defined(__APPLE__)
    #include <mach/mach_time.h>
#elif defined(linux) || defined(__linux) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__GLIBC__) || defined(__GNU__)
    #include <time.h>
#elif defined(sun) || defined(__sun) || defined(_AIX)
    #include <sys/time.h>
#else /* Unsupported OS */
    #error "Rcpp::Timer not supported by your OS."
#endif

namespace Rcpp{
     
      
#if defined(_WIN32)   

    nanotime_t get_nanotime(void) {
        LARGE_INTEGER time_var, frequency;
        QueryPerformanceCounter(&time_var);
        QueryPerformanceFrequency(&frequency);
        
        /* Convert to nanoseconds */
        return 1.0e9 * time_var.QuadPart / frequency.QuadPart;
    }

#elif defined(__APPLE__)
     
    nanotime_t get_nanotime(void) {
        nanotime_t time;
        mach_timebase_info_data_t info;
        
        time = mach_absolute_time();
        mach_timebase_info(&info);
        
        /* Convert to nanoseconds */
        return time * (info.numer / info.denom);
    }

#elif defined(linux) || defined(__linux) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__GLIBC__) || defined(__GNU__)

    static const nanotime_t nanoseconds_in_second = static_cast<nanotime_t>(1000000000.0);
    
    nanotime_t get_nanotime(void) {
        struct timespec time_var;
    
        /* Possible other values we could have used are CLOCK_MONOTONIC,
         * which is takes longer to retrieve and CLOCK_PROCESS_CPUTIME_ID
         * which, if I understand it correctly, would require the R
         * process to be bound to one core.
         */
        clock_gettime(CLOCK_REALTIME, &time_var);
    
        nanotime_t sec = time_var.tv_sec;
        nanotime_t nsec = time_var.tv_nsec;
    
        /* Combine both values to one nanoseconds value */
        return (nanoseconds_in_second * sec) + nsec;
    }

#elif defined(sun) || defined(__sun) || defined(_AIX)

    /* short an sweet! */
    nanotime_t get_nanotime(void) {
        return gethrtime();
    }    

#else /* Unsupported OS */
    #error "Rcpp::Benchmark::Timer not supported by your OS."
#endif
    
    Timer::Timer() : data(), start_time( get_nanotime() ){}
    
    void Timer::step( const std::string& name){
        nanotime_t now = get_nanotime() ;
        data.push_back( std::make_pair( name, now - start_time ) ) ;
        start_time = get_nanotime() ; 
    }
      
    namespace{
        std::string get_first( const std::pair<std::string,nanotime_t>& pair ){
            return pair.first ;    
        }
        double get_second( const std::pair<std::string,nanotime_t>& pair ){
            return static_cast<double>(pair.second) ;    
        }
    }
    
    Timer::operator SEXP() const {
        NumericVector out( data.begin(), data.end(), get_second ) ; 
        CharacterVector names( data.begin(), data.end(), get_first ) ;
        out.attr( "names" ) = names ;
        return out ;
    }
}