refactor: Introduce mtdev

With the addition of the kernel MT slots, the MT event protocol
is capable of efficiently propagating changes to a set of tracked
contacts. At the same time, the need to treat a variety of different
kernel drivers is increased. This patch introduces the mtdev, an
abstract MT device which converts all valid MT event formats into
a uniform, slotted type B event stream. A command-line test program
is included.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

1 files changed, 57 insertions, 0 deletions

diff --git a/include/mtdev-evbuf.h b/include/mtdev-evbuf.h
new file mode 100644
index 0000000..6a63d6d
--- /dev/null
+++ b/include/mtdev-evbuf.h
@@ -0,0 +1,57 @@
+/***************************************************************************
+ *
+ * Multitouch X driver
+ * Copyright (C) 2008 Henrik Rydberg <rydberg@euromail.se>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ **************************************************************************/
+
+#ifndef MTDEV_EVBUF_H
+#define MTDEV_EVBUF_H
+
+#include "common.h"
+
+struct EventBuffer {
+        int head;
+        int tail;
+        struct input_event buffer[DIM_EVENTS];
+};
+
+static inline void evbuf_init(struct EventBuffer *evbuf)
+{
+        memset(evbuf, 0, sizeof(*evbuf));
+}
+
+static inline int evbuf_empty(const struct EventBuffer *evbuf)
+{
+        return evbuf->head == evbuf->tail;
+}
+
+static inline void evbuf_push(struct EventBuffer *evbuf,
+                              const struct input_event *ev)
+{
+        evbuf->buffer[evbuf->head++] = *ev;
+        evbuf->head &= DIM_EVENTS - 1;
+}
+
+static inline void evbuf_pop(struct EventBuffer *evbuf,
+                             struct input_event *ev)
+{
+        *ev = evbuf->buffer[evbuf->tail++];
+        evbuf->tail &= DIM_EVENTS - 1;
+}
+
+#endif