From 5fea0c006a1138e4bad4b6330938033ad7fb0887 Mon Sep 17 00:00:00 2001
From: Marcel Holtmann <marcel@holtmann.org>
Date: Tue, 9 Aug 2011 13:40:10 -0700
Subject: gatchat: Add support for sending HDLC frame start and end markers

---
 gatchat/gathdlc.c | 28 ++++++++++++++++++++++------
 gatchat/gathdlc.h |  1 +
 2 files changed, 23 insertions(+), 6 deletions(-)

(limited to 'gatchat')

diff --git a/gatchat/gathdlc.c b/gatchat/gathdlc.c
index de6a9726..53dd1fb5 100644
--- a/gatchat/gathdlc.c
+++ b/gatchat/gathdlc.c
@@ -70,6 +70,8 @@ struct _GAtHDLC {
 	int record_fd;
 	gboolean in_read_handler;
 	gboolean destroyed;
+	gboolean wakeup_sent;
+	gboolean start_frame_marker;
 	gboolean no_carrier_detect;
 	GAtSuspendFunc suspend_func;
 	gpointer suspend_data;
@@ -328,7 +330,6 @@ out:
 GAtHDLC *g_at_hdlc_new_from_io(GAtIO *io)
 {
 	GAtHDLC *hdlc;
-	unsigned char *buf;
 	struct ring_buffer* write_buffer;
 
 	if (io == NULL)
@@ -357,11 +358,6 @@ GAtHDLC *g_at_hdlc_new_from_io(GAtIO *io)
 
 	g_queue_push_tail(hdlc->write_queue, write_buffer);
 
-	/* Write an initial 0x7e as wakeup character */
-	buf = ring_buffer_write_ptr(write_buffer, 0);
-	*buf = HDLC_FLAG;
-	ring_buffer_write_advance(write_buffer, 1);
-
 	hdlc->decode_buffer = g_try_malloc(BUFFER_SIZE);
 	if (!hdlc->decode_buffer)
 		goto error;
@@ -563,6 +559,17 @@ gboolean g_at_hdlc_send(GAtHDLC *hdlc, const unsigned char *data, gsize size)
 	i = 0;
 	buf = ring_buffer_write_ptr(write_buffer, 0);
 
+	if (hdlc->start_frame_marker == TRUE) {
+		/* Protocol requires 0x7e as start marker */
+		*buf++ = HDLC_FLAG;
+		pos++;
+	} else if (hdlc->wakeup_sent == FALSE) {
+		/* Write an initial 0x7e as wakeup character */
+		*buf++ = HDLC_FLAG;
+		pos++;
+		hdlc->wakeup_sent = TRUE;
+	}
+
 	while (pos < avail && i < size) {
 		if (escape == TRUE) {
 			fcs = HDLC_FCS(fcs, data[i]);
@@ -616,6 +623,7 @@ gboolean g_at_hdlc_send(GAtHDLC *hdlc, const unsigned char *data, gsize size)
 	if (pos + 1 > avail)
 		return FALSE;
 
+	/* Add 0x7e as end marker */
 	*buf = HDLC_FLAG;
 	pos++;
 
@@ -626,6 +634,14 @@ gboolean g_at_hdlc_send(GAtHDLC *hdlc, const unsigned char *data, gsize size)
 	return TRUE;
 }
 
+void g_at_hdlc_set_start_frame_marker(GAtHDLC *hdlc, gboolean marker)
+{
+	if (hdlc == NULL)
+		return;
+
+	hdlc->start_frame_marker = marker;
+}
+
 void g_at_hdlc_set_no_carrier_detect(GAtHDLC *hdlc, gboolean detect)
 {
 	if (hdlc == NULL)
diff --git a/gatchat/gathdlc.h b/gatchat/gathdlc.h
index e82b33e2..a7aab2fe 100644
--- a/gatchat/gathdlc.h
+++ b/gatchat/gathdlc.h
@@ -55,6 +55,7 @@ void g_at_hdlc_set_recording(GAtHDLC *hdlc, const char *filename);
 
 GAtIO *g_at_hdlc_get_io(GAtHDLC *hdlc);
 
+void g_at_hdlc_set_start_frame_marker(GAtHDLC *hdlc, gboolean marker);
 void g_at_hdlc_set_no_carrier_detect(GAtHDLC *hdlc, gboolean detect);
 
 void g_at_hdlc_set_suspend_function(GAtHDLC *hdlc, GAtSuspendFunc func,
-- 
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