//  boost process_cpu_clocks.cpp  -----------------------------------------------------------//

//  Copyright Beman Dawes 1994, 2006, 2008
//  Copyright Vicente J. Botet Escriba 2009

//  Distributed under the Boost Software License, Version 1.0.
//  See http://www.boost.org/LICENSE_1_0.txt

//  See http://www.boost.org/libs/chrono for documentation.

//--------------------------------------------------------------------------------------//

#include <boost/chrono/config.hpp>
#include <boost/chrono/process_cpu_clocks.hpp>
#include <boost/assert.hpp>

# include <sys/times.h>
# include <unistd.h>


namespace boost { namespace chrono {
namespace chrono_detail
{
  inline long tick_factor()        // multiplier to convert ticks
                            //  to nanoseconds; -1 if unknown
  {
    static long factor = 0;
    if ( !factor )
    {
      if ( (factor = ::sysconf( _SC_CLK_TCK )) <= 0 )
        factor = -1;
      else
      {
        BOOST_ASSERT( factor <= 1000000l ); // doesn't handle large ticks
        factor = 1000000l / factor;  // compute factor
        if ( !factor ) factor = -1;
      }
    }
    return factor;
  }
}

process_real_cpu_clock::time_point process_real_cpu_clock::now(
        system::error_code & ec) 
{
    
    tms tm;
    clock_t c = ::times( &tm );
    if ( c == clock_t(-1) ) // error
    {
        if (BOOST_CHRONO_IS_THROWS(ec))
        {
            boost::throw_exception(
                    system::system_error( 
                            errno, 
                            BOOST_CHRONO_SYSTEM_CATEGORY, 
                            "chrono::process_real_cpu_clock" ));
        }
        else
        {
            ec.assign( errno, BOOST_CHRONO_SYSTEM_CATEGORY );
            return time_point();
        }
    }
    else
    {
        if ( chrono_detail::tick_factor() != -1 )
        {
            if (!BOOST_CHRONO_IS_THROWS(ec)) 
            {
                ec.clear();
            }
            return time_point(
                    microseconds(c)*chrono_detail::tick_factor());
        }
        else
        {
            if (BOOST_CHRONO_IS_THROWS(ec))
            {
                boost::throw_exception(
                        system::system_error( 
                                errno, 
                                BOOST_CHRONO_SYSTEM_CATEGORY, 
                                "chrono::process_real_cpu_clock" ));
            }
            else
            {
                ec.assign( errno, BOOST_CHRONO_SYSTEM_CATEGORY );
                return time_point();
            }
        }
    }
}

process_user_cpu_clock::time_point process_user_cpu_clock::now(
        system::error_code & ec)
{
    tms tm;
    clock_t c = ::times( &tm );
    if ( c == clock_t(-1) ) // error
    {
        if (BOOST_CHRONO_IS_THROWS(ec))
        {
            boost::throw_exception(
                    system::system_error( 
                            errno, 
                            BOOST_CHRONO_SYSTEM_CATEGORY, 
                            "chrono::process_user_cpu_clock" ));
        }
        else
        {
            ec.assign( errno, BOOST_CHRONO_SYSTEM_CATEGORY );
            return time_point();
        }
    }
    else
    {
        if ( chrono_detail::tick_factor() != -1 )
        {
            if (!BOOST_CHRONO_IS_THROWS(ec)) 
            {
                ec.clear();
            }
            return time_point(
                    microseconds(tm.tms_utime + tm.tms_cutime)*chrono_detail::tick_factor());
        }
        else
        {
            if (BOOST_CHRONO_IS_THROWS(ec))
            {
                boost::throw_exception(
                        system::system_error( 
                                errno, 
                                BOOST_CHRONO_SYSTEM_CATEGORY, 
                                "chrono::process_user_cpu_clock" ));
            }
            else
            {
                ec.assign( errno, BOOST_CHRONO_SYSTEM_CATEGORY );
                return time_point();
            }
        }
    }
}

process_system_cpu_clock::time_point process_system_cpu_clock::now(
        system::error_code & ec) 
{
    tms tm;
    clock_t c = ::times( &tm );
    if ( c == clock_t(-1) ) // error
    {
        if (BOOST_CHRONO_IS_THROWS(ec))
        {
            boost::throw_exception(
                    system::system_error( 
                            errno, 
                            BOOST_CHRONO_SYSTEM_CATEGORY, 
                            "chrono::process_system_cpu_clock" ));
        }
        else
        {
            ec.assign( errno, BOOST_CHRONO_SYSTEM_CATEGORY );
            return time_point();
        }
    }
    else
    {
        if ( chrono_detail::tick_factor() != -1 )
        {
            if (!BOOST_CHRONO_IS_THROWS(ec)) 
            {
                ec.clear();
            }
            return time_point(
                    microseconds(tm.tms_stime + tm.tms_cstime)*chrono_detail::tick_factor());
        }
        else
        {
            if (BOOST_CHRONO_IS_THROWS(ec))
            {
                boost::throw_exception(
                        system::system_error( 
                                errno, 
                                BOOST_CHRONO_SYSTEM_CATEGORY, 
                                "chrono::process_system_cpu_clock" ));
            }
            else
            {
                ec.assign( errno, BOOST_CHRONO_SYSTEM_CATEGORY );
                return time_point();
            }
        }
    }
}

process_cpu_clock::time_point process_cpu_clock::now( 
        system::error_code & ec ) 
{
    
    
    tms tm;
    clock_t c = ::times( &tm );
    if ( c == clock_t(-1) ) // error
    {
        if (BOOST_CHRONO_IS_THROWS(ec))
        {
            boost::throw_exception(
                    system::system_error( 
                            errno, 
                            BOOST_CHRONO_SYSTEM_CATEGORY, 
                            "chrono::process_clock" ));
        }
        else
        {
            ec.assign( errno, BOOST_CHRONO_SYSTEM_CATEGORY );
            return time_point();
        }
    }
    else
    {
        if ( chrono_detail::tick_factor() != -1 )
        {
            time_point::rep r(
                    c*chrono_detail::tick_factor(), 
                    (tm.tms_utime + tm.tms_cutime)*chrono_detail::tick_factor(), 
                    (tm.tms_stime + tm.tms_cstime)*chrono_detail::tick_factor());
            return time_point(duration(r));
        }
        else
        {
            if (BOOST_CHRONO_IS_THROWS(ec))
            {
                boost::throw_exception(
                        system::system_error( 
                                errno, 
                                BOOST_CHRONO_SYSTEM_CATEGORY, 
                                "chrono::process_clock" ));
            }
            else
            {
                ec.assign( errno, BOOST_CHRONO_SYSTEM_CATEGORY );
                return time_point();
            }
        }
    }
    
}

} }