Implement streaming protocol (mw_feed_...)

metawatch.c

@@ -480,7 +480,7 @@ void mw_set_status_change_event_cb(mwdevice_t *mwdevice, void (*mw_status_change
  * Protocol handling
  * ---------------------------------------------------------------------- */
 
-int decode_frame(mwdevice_t *mwdevice, unsigned char *buf, int len)
+int mw_decode_frame(mwdevice_t *mwdevice, unsigned char *buf, int len)
 {
 	unsigned short crc;
 	unsigned char msglen;
@@ -547,6 +547,38 @@ int decode_frame(mwdevice_t *mwdevice, unsigned char *buf, int len)
 }
 
 
+int mw_feed_msg_buffer(mwdevice_t *mwdevice, unsigned char *buf, int len)
+{
+	char msgbuf[64];
+	int tlen;
+
+	if (len <= 0)
+		return -1;
+
+	memcpy((mwdevice->pbuf+mwdevice->pbuf_len), buf, len);
+	mwdevice->pbuf_len += len;
+	
+	while (mwdevice->pbuf_len > 0) {
+		/* scan for MW_SOF */
+		while (mwdevice->pbuf[0] != MW_SOF) {
+			memmove(mwdevice->pbuf, (mwdevice->pbuf+1), --mwdevice->pbuf_len);
+		}
+		tlen = mwdevice->pbuf[1];
+		/* OK, there is an SOF but the message is too short */
+		if (tlen > mwdevice->pbuf_len) {
+			/* we have to wait for more data to come in */
+			break;
+		}
+		/* here we have a complete msg */
+		memcpy(msgbuf, mwdevice->pbuf, tlen);
+		mw_decode_frame(mwdevice, msgbuf, tlen);
+		memmove(mwdevice->pbuf, (mwdevice->pbuf+tlen), tlen);
+		mwdevice->pbuf_len -= tlen;
+	}
+	return 0;
+}
+
+
 /* ----------------------------------------------------------------------
  * General code usage
  * ---------------------------------------------------------------------- */
@@ -555,6 +587,8 @@ int mw_init(mwdevice_t *mwdevice, int mw_fd)
 {
 	memset(mwdevice, 0, sizeof(mwdevice_t));
 	mwdevice->mw_fd = mw_fd;
+	memset(mwdevice->pbuf, 0, MW_PBUF_LEN);
+	mwdevice->pbuf_len = 0;
 
 	/* figure out which device we run with */
 	mw_send_frame(mwdevice, MW_GET_DEVICE_TYPE, 0, NULL, 0);

metawatch.h

@@ -10,8 +10,12 @@
 #include <time.h>
 #include "metawatch_protocol.h"
 
+#define MW_PBUF_LEN 512
+
 typedef struct _mwdevice_t {
 	int mw_fd;		/* file decriptor for MW connection */
+	char pbuf[MW_PBUF_LEN];	/* protocol receive buffer */
+	int pbuf_len;
 	unsigned char devtype;	/* the device type of the connected device */
 	/* watch message callbacks */
 	void (*mw_get_device_type_response_cb) (struct _mwdevice_t *mwdevice, unsigned char devtype, void *user_data);
@@ -79,7 +83,9 @@ int mw_disable_button(mwdevice_t *mwdevice, unsigned char mode, unsigned char bu
 
 int mw_advance_watch_hands(mwdevice_t *mwdevice, unsigned char hours, unsigned char minutes, unsigned char seconds);
 
-int decode_frame(mwdevice_t *mwdevice, unsigned char *buf, int len);
+int mw_decode_frame(mwdevice_t *mwdevice, unsigned char *buf, int len);
+
+int mw_feed_msg_buffer(mwdevice_t *mwdevice, unsigned char *buf, int len);
 
 int mw_init(mwdevice_t *mwdevice, int mw_fd);
 

mw_main.c

@@ -448,7 +448,7 @@ gboolean handle_mw_io(GIOChannel *mw_io, GIOCondition condition, gpointer udata)
 	mwdata_t *mdata = (mwdata_t *)udata;
 	int rcvd;
 
-	rcvd = read(mdata->mwdevice.mw_fd, mdata->rcvbuf+mdata->rcvbuf_pos, 64);
+	rcvd = read(mdata->mwdevice.mw_fd, mdata->rcvbuf, 64);
 #ifdef DEBUG
 	fprintf(stderr, "read %d bytes:\n", rcvd);
 #endif
@@ -456,8 +456,7 @@ gboolean handle_mw_io(GIOChannel *mw_io, GIOCondition condition, gpointer udata)
 #ifdef DEBUG
 		dump_frame(mdata->rcvbuf, rcvd);
 #endif
-		decode_frame(&mdata->mwdevice, mdata->rcvbuf, rcvd);
+		mw_feed_msg_buffer(&mdata->mwdevice, mdata->rcvbuf, rcvd);
-		mdata->rcvbuf_pos = 0;
 	}
 
 	return TRUE;