--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/project_files/frontlib/ipc/ipcbase.h	Tue Jun 19 21:17:05 2012 +0200
@@ -0,0 +1,86 @@
+/*
+ * Low-level protocol support for the IPC connection to the engine.
+ */
+
+#ifndef IPCBASE_H_
+#define IPCBASE_H_
+
+#include <stddef.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#define IPCBASE_MAPMSG_BYTES 4097
+
+typedef enum {IPC_NOT_CONNECTED, IPC_LISTENING, IPC_CONNECTED} IpcState;
+
+struct _flib_ipcbase;
+typedef struct _flib_ipcbase flib_ipcbase;
+
+/**
+ * Start an engine connection by listening on a random port. The selected port can
+ * be queried with flib_ipcbase_port and has to be passed to the engine.
+ *
+ * Returns NULL on error. Destroy the created object with flib_ipcbase_destroy.
+ *
+ * We stop accepting new connections once a connection has been established, so you
+ * need to create a new ipcbase in order to start a new connection.
+ */
+flib_ipcbase *flib_ipcbase_create();
+
+uint16_t flib_ipcbase_port(flib_ipcbase *ipc);
+
+/**
+ * Free resources and close sockets.
+ */
+void flib_ipcbase_destroy(flib_ipcbase *ipc);
+
+/**
+ * Determine the current connection state
+ */
+IpcState flib_ipcbase_state(flib_ipcbase *ipc);
+
+/**
+ * Receive a single message (up to 256 bytes) and copy it into the data buffer.
+ * Returns the length of the received message, a negative value if no message could
+ * be read.
+ *
+ * The first byte of a message is its content length, which is one less than the returned
+ * value.
+ *
+ * Note: When a connection is closed, you probably want to call this function until
+ * no further message is returned, to ensure you see all messages that were sent
+ * before the connection closed.
+ */
+int flib_ipcbase_recv_message(flib_ipcbase *ipc, void *data);
+
+/**
+ * Try to receive 4097 bytes. This is the size of the reply the engine sends
+ * when successfully queried for map data. The first 4096 bytes are a bit-packed
+ * twocolor image of the map (256x128), the last byte is the number of hogs that
+ * fit on the map.
+ */
+int flib_ipcbase_recv_map(flib_ipcbase *ipc, void *data);
+
+int flib_ipcbase_send_raw(flib_ipcbase *ipc, const void *data, size_t len);
+
+/**
+ * Write a single message (up to 255 bytes) to the engine. This call blocks until the
+ * message is completely written or the connection is closed or an error occurs.
+ *
+ * Calling this function in a state other than IPC_CONNECTED will fail immediately.
+ * Returns a negative value on failure.
+ */
+int flib_ipcbase_send_message(flib_ipcbase *ipc, void *data, size_t len);
+
+/**
+ * Convenience function for sending a 0-delimited string.
+ */
+int flib_ipcbase_send_messagestr(flib_ipcbase *ipc, char *data);
+
+/**
+ * Try to accept a connection. Only has an effect in state IPC_LISTENING.
+ */
+void flib_ipcbase_accept(flib_ipcbase *ipc);
+
+#endif /* IPCBASE_H_ */
+