1 /*

     2  * Hedgewars, a free turn based strategy game

     3  * Copyright (C) 2012 Simeon Maxein <smaxein@googlemail.com>

     4  *

     5  * This program is free software; you can redistribute it and/or

     6  * modify it under the terms of the GNU General Public License

     7  * as published by the Free Software Foundation; either version 2

     8  * of the License, or (at your option) any later version.

     9  *

    10  * This program is distributed in the hope that it will be useful,

    11  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    13  * GNU General Public License for more details.

    14  *

    15  * You should have received a copy of the GNU General Public License

    16  * along with this program; if not, write to the Free Software

    17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

    18  */

    19 

    20 /*

    21  * Low-level protocol support for the IPC connection to the engine.

    22  */

    23 #ifndef IPCBASE_H_

    24 #define IPCBASE_H_

    25 

    26 #include <stddef.h>

    27 #include <stdbool.h>

    28 #include <stdint.h>

    29 

    30 #define IPCBASE_MAPMSG_BYTES 4097

    31 

    32 typedef enum {IPC_NOT_CONNECTED, IPC_LISTENING, IPC_CONNECTED} IpcState;

    33 

    34 typedef struct _flib_ipcbase flib_ipcbase;

    35 

    36 /**

    37  * Start an engine connection by listening on a random port. The selected port can

    38  * be queried with flib_ipcbase_port and has to be passed to the engine.

    39  *

    40  * Returns NULL on error. Destroy the created object with flib_ipcbase_destroy.

    41  *

    42  * We stop accepting new connections once a connection has been established, so you

    43  * need to create a new ipcbase in order to start a new connection.

    44  */

    45 flib_ipcbase *flib_ipcbase_create();

    46 

    47 /**

    48  * Return the listening port

    49  */

    50 uint16_t flib_ipcbase_port(flib_ipcbase *ipc);

    51 

    52 /**

    53  * Free resources and close sockets. NULL safe.

    54  */

    55 void flib_ipcbase_destroy(flib_ipcbase *ipc);

    56 

    57 /**

    58  * Determine the current connection state

    59  */

    60 IpcState flib_ipcbase_state(flib_ipcbase *ipc);

    61 

    62 /**

    63  * Receive a single message (up to 256 bytes) and copy it into the data buffer.

    64  * Returns the length of the received message, a negative value if no message could

    65  * be read.

    66  *

    67  * The first byte of a message is its content length, which is one less than the returned

    68  * value.

    69  *

    70  * Note: When a connection is closed, you probably want to call this function until

    71  * no further message is returned, to ensure you see all messages that were sent

    72  * before the connection closed.

    73  */

    74 int flib_ipcbase_recv_message(flib_ipcbase *ipc, void *data);

    75 

    76 /**

    77  * Try to receive 4097 bytes. This is the size of the reply the engine sends

    78  * when successfully queried for map data. The first 4096 bytes are a bit-packed

    79  * twocolor image of the map (256x128), the last byte is the number of hogs that

    80  * fit on the map.

    81  */

    82 int flib_ipcbase_recv_map(flib_ipcbase *ipc, void *data);

    83 

    84 /**

    85  * Blocking send bytes over the socket. No message framing will be added.

    86  * Returns 0 on success.

    87  */

    88 int flib_ipcbase_send_raw(flib_ipcbase *ipc, const void *data, size_t len);

    89 

    90 /**

    91  * Write a single message (up to 255 bytes) to the engine. This call blocks until the

    92  * message is completely written or the connection is closed or an error occurs.

    93  *

    94  * Calling this function in a state other than IPC_CONNECTED will fail immediately.

    95  * Returns 0 on success.

    96  */

    97 int flib_ipcbase_send_message(flib_ipcbase *ipc, void *data, size_t len);

    98 

    99 /**

   100  * Try to accept a connection. Only has an effect in state IPC_LISTENING.

   101  */

   102 void flib_ipcbase_accept(flib_ipcbase *ipc);

   103 

   104 #endif /* IPCBASE_H_ */

   105