socket_selector.h

#ifndef __SOCKET_SELECTOR_H__
#define __SOCKET_SELECTOR_H__

// This is a structure on purpose.  only used as a helper class to save on
// typing
struct Socket_Selector
{
    Socket_fdset _read;
    Socket_fdset _write;
    Socket_fdset _error;
    int         _answer;

    Socket_Selector() : _answer( -1)
    {
    }

    Socket_Selector(const Socket_fdset &fd) : _read(fd), _write(fd), _error(fd) , _answer( -1)
    {
    }

    int WaitFor(const Time_Span &timeout);
    int WaitFor_All(const Socket_fdset & fd, const Time_Span & timeout);
    int WaitFor_Read_Error(const Socket_fdset & fd, const Time_Span & timeout);
    int WaitFor_Write_Error(const Socket_fdset & fd, const Time_Span & timeout);
};

/**
 * This function is the reason this call exists.. It will wait for a read,
 * write or error condition on a socket or it will time out
 */
inline int Socket_Selector::WaitFor(const Time_Span &timeout)
{
    SOCKET local_max = 0;
    if (local_max < _read._maxid)
        local_max = _read._maxid;
    if (local_max < _write._maxid)
        local_max = _write._maxid;
    if (local_max < _error._maxid)
        local_max = _error._maxid;

    timeval localtv = timeout.GetTval();
    _answer = DO_SELECT(local_max + 1, &_read._the_set, &_write._the_set, &_error._the_set, &localtv);
    return _answer;
}

/**
 * Helper function to utilize the WaitFor function
 */
inline int Socket_Selector::WaitFor_All(const Socket_fdset & fd, const Time_Span & timeout)
{
    _read = fd;
    _write = fd;
    _error = fd;
    return WaitFor(timeout);
}

/**
 * Helper function for WaitFor Only looks for readability and errors
 */
inline int Socket_Selector::WaitFor_Read_Error(const Socket_fdset & fd, const Time_Span & timeout)
{
    _read = fd;
    _write.clear();
    _error = fd;
    return WaitFor(timeout);
}

/**
 * Helper function for WaitFor Only looks for writability and errors
 */
inline int Socket_Selector::WaitFor_Write_Error(const Socket_fdset & fd, const Time_Span & timeout)
{
    _read.clear();
    _write = fd;
    _error = fd;
    return WaitFor(timeout);
}

#endif //__SOCKET_SELECTOR_H__