dtmf: Schedule DTMF tones for the MTN hardware

Create a simple queue for pending DTMF tones, play them using the
MTN API, and then send the next tones once the playback is complete.
The callback and scheduling is done from the same context so no locking
needs to be done.

1 files changed, 59 insertions, 0 deletions

diff --git a/src/dtmf_scheduler.c b/src/dtmf_scheduler.c
new file mode 100644
index 0000000..26dc090
--- /dev/null
+++ b/src/dtmf_scheduler.c
@@ -0,0 +1,59 @@
+/*
+ * (C) 2012 by Holger Hans Peter Freyther
+ * (C) 2012 by On-Waves
+ * All Rights Reserved
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "dtmf_scheduler.h"
+#include <string.h>
+#include <stdio.h>
+
+void dtmf_state_init(struct dtmf_state *state)
+{
+	memset(state, 0, sizeof(*state));
+}
+
+int dtmf_state_add(struct dtmf_state *state, char tone)
+{
+	/* we would override the head */
+	if (state->size == sizeof(state->tones))
+		return -1;
+
+	state->tones[state->size++] = tone;
+	return 0;
+}
+
+void dtmf_state_get_pending(struct dtmf_state *state, char *tones)
+{
+	int pos;
+
+	for (pos = 0; pos < state->size; ++pos)
+		tones[pos] = state->tones[pos];
+
+	/* consume everything up to the tail */
+	state->size = 0;
+
+	/* remember that we play things */
+	if (pos > 0)
+		state->playing = 1;
+	tones[pos] = '\0';
+}
+
+void dtmf_state_played(struct dtmf_state *state)
+{
+	state->playing = 0;
+}