opencv/modules/core/src/parallel.cpp

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#include "precomp.hpp"

#if !defined HAVE_TBB && !defined HAVE_OPENMP && !defined HAVE_GCD && !defined HAVE_CONCURRENCY
    #ifdef __APPLE__
        //#define HAVE_GDC
    #elif defined _MSC_VER && _MSC_VER >= 1600
        #define HAVE_CONCURRENCY
    #endif
#endif

#ifdef HAVE_CONCURRENCY
    #include <ppl.h>
#elif defined HAVE_OPENMP
    #include <omp.h>
#elif defined HAVE_GCD
    #include <dispatch/dispatch.h>
#elif defined HAVE_TBB
    #include "tbb/tbb_stddef.h"
    #if TBB_VERSION_MAJOR*100 + TBB_VERSION_MINOR >= 202
        #include "tbb/tbb.h"
        #include "tbb/task.h"
        #undef min
        #undef max
    #else
        #undef HAVE_TBB
    #endif // end TBB version
#endif // HAVE_CONCURRENCY

/*
    HAVE_TBB - using TBB
    HAVE_GCD - using GCD
    HAVE_OPENMP - using OpenMP
    HAVE_CONCURRENCY - using visual studio 2010 concurrency
*/

namespace cv
{
    ParallelLoopBody::~ParallelLoopBody() { }

#ifdef HAVE_TBB
    class TbbProxyLoopBody
    {
    public:
        TbbProxyLoopBody(const ParallelLoopBody& _body) :
            body(&_body)
        { }

        void operator ()(const tbb::blocked_range<int>& range) const
        {
            body->operator()(Range(range.begin(), range.end()));
        }

    private:
        const ParallelLoopBody* body;
    };
#endif // end HAVE_TBB

#ifdef HAVE_GCD
    static
    void block_function(void* context, size_t index)
    {
        ParallelLoopBody* ptr_body = static_cast<ParallelLoopBody*>(context);
        ptr_body->operator()(Range(index, index + 1));
    }
#endif // HAVE_GCD

    void parallel_for_(const Range& range, const ParallelLoopBody& body)
    {
#ifdef HAVE_TBB

        tbb::parallel_for(tbb::blocked_range<int>(range.start, range.end), TbbProxyLoopBody(body));

#elif defined HAVE_CONCURRENCY

        class ConcurrencyProxyLoopBody
        {
        public:
            ConcurrencyProxyLoopBody(const ParallelLoopBody& body) : _body(body) {}

            void operator ()(int i) const
            {
                _body(Range(i, i + 1));
            }

        private:
            const ParallelLoopBody& _body;
            ConcurrencyProxyLoopBody& operator=(const ConcurrencyProxyLoopBody&) {return *this;}
        } proxy(body);

        Concurrency::parallel_for(range.start, range.end, proxy);

#elif defined HAVE_OPENMP

#pragma omp parallel for schedule(dynamic)
        for (int i = range.start; i < range.end; ++i)
            body(Range(i, i + 1));

#elif defined (HAVE_GCD)

        dispatch_queue_t concurrent_queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
        dispatch_apply_f(range.end - range.start, concurrent_queue, &const_cast<ParallelLoopBody&>(body), block_function);

#else

        body(range);

#endif // end HAVE_TBB
    }

} // namespace cv