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/*! \libinternal \file
 *
 * \brief
 * Implements the parts of the vmdsock.h interface needed for IMD communication.
 *
 * \author Martin Hoefling, Carsten Kutzner <ckutzne@gwdg.de>
 *
 * For more information, see https://www-s.ks.uiuc.edu/Research/vmd/imd/ for general
 * IMD information and https://www-s.ks.uiuc.edu/Research/vmd/imd/code/imdapi.tar.gz
 * for the IMD reference implementation and API.
 *
 * \inlibraryapi
 * \ingroup module_imd
 */

#ifndef GMX_IMD_IMDSOCKET_H
#define GMX_IMD_IMDSOCKET_H

namespace gmx
{

struct IMDSocket;


/*! \internal
 *
 * \brief Function to initialize winsock
 *
 * \returns 0 if successful.
 */
int imdsock_winsockinit();

/*! \brief Create an IMD main socket.
 *
 * \returns  The IMD socket if successful. Otherwise prints an error message and returns NULL.
 */
IMDSocket* imdsock_create();

//! Portability wrapper around sleep function
void imd_sleep(unsigned int seconds);


/*! \brief Bind the IMD socket to address and port.
 *
 * Prints out an error message if unsuccessful.
 * If port == 0, bind() assigns a free port automatically.
 *
 *
 * \param sock      The IMD socket.
 * \param port      The port to bind to.
 *
 * \returns 0 if successful.
 */
int imdsock_bind(IMDSocket* sock, int port);


/*! \brief Set socket to listening state.
 *
 * Prints out an error message if unsuccessful.
 *
 * \param sock      The IMD socket.
 *
 * \returns 0 if successful.
 *
 */
int imd_sock_listen(IMDSocket* sock);


/*! \brief Accept incoming connection and redirect to client socket.
 *
 * Prints out an error message if unsuccessful.
 *
 * \param sock      The IMD socket.
 *
 * \returns IMD socket if successful, NULL otherwise.
 */
IMDSocket* imdsock_accept(IMDSocket* sock);


/*! \brief Get the port number used for IMD connection.
 *
 * Prints out an error message if unsuccessful.
 *
 * \param sock      The IMD socket.
 * \param port      The assigned port number.
 *
 * \returns 0 if successful, an error code otherwise.
 */
int imdsock_getport(IMDSocket* sock, int* port);

//! Portability wrapper around system htonl function.
int imd_htonl(int src);

//! Portability wrapper around system ntohl function.
int imd_ntohl(int src);


/*! \brief  Write to socket.
 *
 *
 * \param sock      The IMD socket.
 * \param buffer    The data to write.
 * \param length    Number of bytes to write.
 *
 * \returns The number of bytes written, or -1.
 */
int imdsock_write(IMDSocket* sock, const char* buffer, int length);


/*! \brief  Read from socket.
 *
 * \param sock      The IMD socket.
 * \param buffer    Buffer to put the read data.
 * \param length    Number of bytes to read.
 *
 * \returns The number of bytes read, or -1 for errors.
 */
int imdsock_read(IMDSocket* sock, char* buffer, int length);


/*! \brief Shutdown the socket.
 *
 * \param sock      The IMD socket.
 *
 */
void imdsock_shutdown(IMDSocket* sock);


/*! \brief Close the socket and free the sock struct memory.
 *
 * Writes an error message if unsuccessful.
 *
 * \param sock      The IMD socket.
 *
 * \returns 1 on success, or 0 if unsuccessful.
 */
int imdsock_destroy(IMDSocket* sock);


/*! \brief Try to read from the socket.
 *
 * Time out after waiting the interval specified.
 * Print an error message if unsuccessful.
 *
 * \param sock         The IMD socket.
 * \param timeoutsec   Time out seconds
 * \param timeoutusec  Time out microseconds
 *
 */
int imdsock_tryread(IMDSocket* sock, int timeoutsec, int timeoutusec);

} // namespace gmx

#endif
