parallel_for.h

/*
    Copyright 2005-2016 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks. Threading Building Blocks is free software;
    you can redistribute it and/or modify it under the terms of the GNU General Public License
    version 2  as  published  by  the  Free Software Foundation.  Threading Building Blocks 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 Threading Building Blocks; if not, write to the
    Free Software Foundation, Inc.,  51 Franklin St,  Fifth Floor,  Boston,  MA 02110-1301 USA

    As a special exception,  you may use this file  as part of a free software library without
    restriction.  Specifically,  if other files instantiate templates  or use macros or inline
    functions from this file, or you compile this file and link it with other files to produce
    an executable,  this file does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however invalidate any other
    reasons why the executable file might be covered by the GNU General Public License.
*/

#ifndef __TBB_SERIAL_parallel_for_H
#define __TBB_SERIAL_parallel_for_H

#if !TBB_USE_EXCEPTIONS && _MSC_VER
    // Suppress "C++ exception handler used, but unwind semantics are not enabled" warning in STL headers
    #pragma warning (push)
    #pragma warning (disable: 4530)
#endif

#include <stdexcept>
#include <string> // required to construct std exception classes

#if !TBB_USE_EXCEPTIONS && _MSC_VER
    #pragma warning (pop)
#endif

#include "tbb_annotate.h"

#ifndef __TBB_NORMAL_EXECUTION
#include "tbb/blocked_range.h"
#include "tbb/partitioner.h"
#endif

namespace tbb {
namespace serial {
namespace interface9 {

// parallel_for serial annotated implementation

template< typename Range, typename Body, typename Partitioner >
class start_for : tbb::internal::no_copy {
    Range my_range;
    const Body my_body;
    typename Partitioner::task_partition_type my_partition;
    void execute();

    start_for( const Range& range, const Body& body, Partitioner& partitioner ) :
        my_range( range ),
        my_body( body ),
        my_partition( partitioner )
    {
    }


    start_for( start_for& parent_, typename Partitioner::split_type& split_obj ) :
        my_range( parent_.my_range, split_obj ),
        my_body( parent_.my_body ),
        my_partition( parent_.my_partition, split_obj )
    {
    }

public:
    static void run(  const Range& range, const Body& body, Partitioner& partitioner ) {
        if( !range.empty() ) {
            ANNOTATE_SITE_BEGIN( tbb_parallel_for );
            {
                start_for a( range, body, partitioner );
                a.execute();
            }
            ANNOTATE_SITE_END( tbb_parallel_for );
        }
    }
};

template< typename Range, typename Body, typename Partitioner >
void start_for< Range, Body, Partitioner >::execute() {
    if( !my_range.is_divisible() || !my_partition.is_divisible() ) {
        ANNOTATE_TASK_BEGIN( tbb_parallel_for_range );
        {
            my_body( my_range );
        }
        ANNOTATE_TASK_END( tbb_parallel_for_range );
    } else {
        typename Partitioner::split_type split_obj;
        start_for b( *this, split_obj );
        this->execute(); // Execute the left interval first to keep the serial order.
        b.execute();     // Execute the right interval then.
    }
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body ) {
    serial::interface9::start_for<Range,Body,const __TBB_DEFAULT_PARTITIONER>::run(range,body,__TBB_DEFAULT_PARTITIONER());
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const simple_partitioner& partitioner ) {
    serial::interface9::start_for<Range,Body,const simple_partitioner>::run(range,body,partitioner);
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const auto_partitioner& partitioner ) {
    serial::interface9::start_for<Range,Body,const auto_partitioner>::run(range,body,partitioner);
}

#if TBB_PREVIEW_STATIC_PARTITIONER

template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const static_partitioner& partitioner ) {
    serial::interface9::start_for<Range,Body,const static_partitioner>::run(range,body,partitioner);
}
#endif


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, affinity_partitioner& partitioner ) {
    serial::interface9::start_for<Range,Body,affinity_partitioner>::run(range,body,partitioner);
}

template <typename Index, typename Function, typename Partitioner>
void parallel_for_impl(Index first, Index last, Index step, const Function& f, Partitioner& ) {
    if (step <= 0 )
        throw std::invalid_argument( "nonpositive_step" );
    else if (last > first) {
        // Above "else" avoids "potential divide by zero" warning on some platforms
        ANNOTATE_SITE_BEGIN( tbb_parallel_for );
        for( Index i = first; i < last; i = i + step ) {
            ANNOTATE_TASK_BEGIN( tbb_parallel_for_iteration );
            { f( i ); }
            ANNOTATE_TASK_END( tbb_parallel_for_iteration );
        }
        ANNOTATE_SITE_END( tbb_parallel_for );
    }
}

template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, step, f, auto_partitioner());
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const simple_partitioner& p) {
    parallel_for_impl<Index,Function,const simple_partitioner>(first, last, step, f, p);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const auto_partitioner& p) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, step, f, p);
}
#if TBB_PREVIEW_STATIC_PARTITIONER
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const static_partitioner& p) {
    parallel_for_impl<Index,Function,const static_partitioner>(first, last, step, f, p);
}
#endif
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, affinity_partitioner& p) {
    parallel_for_impl(first, last, step, f, p);
}

template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, static_cast<Index>(1), f, auto_partitioner());
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, const simple_partitioner& p) {
    parallel_for_impl<Index,Function,const simple_partitioner>(first, last, static_cast<Index>(1), f, p);
}
template <typename Index, typename Function>
    void parallel_for(Index first, Index last, const Function& f, const auto_partitioner& p) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, static_cast<Index>(1), f, p);
}
#if TBB_PREVIEW_STATIC_PARTITIONER
template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, const static_partitioner& p) {
    parallel_for_impl<Index,Function,const static_partitioner>(first, last, static_cast<Index>(1), f, p);
}
#endif
template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, affinity_partitioner& p) {
    parallel_for_impl(first, last, static_cast<Index>(1), f, p);
}

} // namespace interfaceX

using interface9::parallel_for;

} // namespace serial

#ifndef __TBB_NORMAL_EXECUTION
using serial::interface9::parallel_for;
#endif

} // namespace tbb

#endif /* __TBB_SERIAL_parallel_for_H */