cppcore/include/cppcore/platform/select.inl

#pragma once

#include "select.h"
#include "../misc/exception.h"
#include "../conversion/time.h"

namespace cppcore
{

    namespace __impl
    {
        inline uint throw_select_error(int err)
        {
            if (err == EINTR)
                return 0;
            throw error_exception("Error while waiting for select operation", err);
        }
    }

    uint select(
        int fd_count,
        fdset& read,
        fdset& write,
        fdset& except)
    {
        auto ret = ::select(fd_count, &read, &write, &except, nullptr);
        if (ret < 0)
            return __impl::throw_select_error(errno);
        return static_cast<uint>(ret);
    }

    template<typename T_rep, typename T_period>
    uint select(
        int fd_count,
        fdset& read,
        fdset& write,
        fdset& except,
        std::chrono::duration<T_rep, T_period>& timeout)
    {
        using duration_type = std::chrono::duration<T_rep, T_period>;

        auto tmp = duration_cast<timeval>(timeout);
        auto ret = ::select(fd_count, &read, &write, &except, &tmp);
        if (ret < 0)
            return __impl::throw_select_error(errno);
        timeout = duration_cast<duration_type>(tmp);
        return static_cast<uint>(ret);
    }

    template<typename T_rep, typename T_period>
    uint select(
        int fd_count,
        fdset& read,
        fdset& write,
        fdset& except,
        const std::chrono::duration<T_rep, T_period>& timeout)
    {
        auto tmp = duration_cast<timeval>(timeout);
        auto ret = ::select(fd_count, &read, &write, &except, &tmp);
        if (ret < 0)
            return __impl::throw_select_error(errno);
        return static_cast<uint>(ret);
    }

}