request_operations.h

/***************************************************************************
 *  include/stxxl/bits/io/request_operations.h
 *
 *  Part of the STXXL. See http://stxxl.sourceforge.net
 *
 *  Copyright (C) 2002 Roman Dementiev <[email protected]>
 *  Copyright (C) 2008, 2009 Andreas Beckmann <[email protected]>
 *  Copyright (C) 2009 Johannes Singler <[email protected]>
 *
 *  Distributed under the Boost Software License, Version 1.0.
 *  (See accompanying file LICENSE_1_0.txt or copy at
 *  http://www.boost.org/LICENSE_1_0.txt)
 **************************************************************************/

#ifndef STXXL_IO__REQUEST_OPERATIONS_H_
#define STXXL_IO__REQUEST_OPERATIONS_H_

#include <stxxl/bits/namespace.h>
#include <stxxl/bits/io/request_ptr.h>
#include <stxxl/bits/io/iostats.h>
#include <stxxl/bits/common/switch.h>


__STXXL_BEGIN_NAMESPACE




template <class request_iterator_>
void wait_all(request_iterator_ reqs_begin, request_iterator_ reqs_end)
{
    for ( ; reqs_begin != reqs_end; ++reqs_begin)
        (request_ptr(*reqs_begin))->wait();
}

inline void wait_all(request_ptr req_array[], int count)
{
    wait_all(req_array, req_array + count);
}

template <class request_iterator_>
typename std::iterator_traits<request_iterator_>::difference_type cancel_all(request_iterator_ reqs_begin, request_iterator_ reqs_end)
{
    typename std::iterator_traits<request_iterator_>::difference_type num_canceled = 0;
    while (reqs_begin != reqs_end)
    {
        if ((request_ptr(*reqs_begin))->cancel())
            ++num_canceled;
        ++reqs_begin;
    }
    return num_canceled;
}

template <class request_iterator_>
request_iterator_ poll_any(request_iterator_ reqs_begin, request_iterator_ reqs_end)
{
    while (reqs_begin != reqs_end)
    {
        if ((request_ptr(*reqs_begin))->poll())
            return reqs_begin;

        ++reqs_begin;
    }
    return reqs_end;
}


inline bool poll_any(request_ptr req_array[], int count, int & index)
{
    request_ptr * res = poll_any(req_array, req_array + count);
    index = res - req_array;
    return res != (req_array + count);
}


template <class request_iterator_>
request_iterator_ wait_any(request_iterator_ reqs_begin, request_iterator_ reqs_end)
{
    stats::scoped_wait_timer wait_timer(stats::WAIT_OP_ANY);

    onoff_switch sw;

    request_iterator_ cur = reqs_begin, result = reqs_end;

    for ( ; cur != reqs_end; cur++)
    {
        if ((request_ptr(*cur))->add_waiter(&sw))
        {
            // request is already done, no waiter was added to the request
            result = cur;

            if (cur != reqs_begin)
            {
                while (--cur != reqs_begin)
                    (request_ptr(*cur))->delete_waiter(&sw);

                (request_ptr(*cur))->delete_waiter(&sw);
            }

            (request_ptr(*result))->check_errors();

            return result;
        }
    }

    sw.wait_for_on();

    for (cur = reqs_begin; cur != reqs_end; cur++)
    {
        (request_ptr(*cur))->delete_waiter(&sw);
        if (result == reqs_end && (request_ptr(*cur))->poll())
            result = cur;
    }

    return result;
}


inline int wait_any(request_ptr req_array[], int count)
{
    return wait_any(req_array, req_array + count) - req_array;
}


__STXXL_END_NAMESPACE

#endif // !STXXL_IO__REQUEST_OPERATIONS_H_
// vim: et:ts=4:sw=4