- int sof;
-
- /* the image ends on a 64 bytes block starting with
- * ff d9 ff ff 00 c4 c4 96
- * and followed by various information including luminosity */
- /* this block may be splitted between two packets */
- /* a new image always starts in a new packet */
- switch (gspca_dev->last_packet_type) {
- case DISCARD_PACKET: /* restart image building */
- sof = len - 64;
- if (sof >= 0 && data[sof] == 0xff && data[sof + 1] == 0xd9)
- gspca_frame_add(gspca_dev, LAST_PACKET, NULL, 0);
- return;
- case LAST_PACKET: /* put the JPEG 422 header */
+ int i;
+
+ /*
+ * A frame ends on the marker
+ * ff ff 00 c4 c4 96 ..
+ * which is 62 bytes long and is followed by various information
+ * including statuses and luminosity.
+ *
+ * A marker may be splitted on two packets.
+ *
+ * The 6th byte of a marker contains the bits:
+ * 0x08: USB full
+ * 0xc0: frame sequence
+ * When the bit 'USB full' is set, the frame must be discarded;
+ * this is also the case when the 2 bytes before the marker are
+ * not the JPEG end of frame ('ff d9').
+ */
+
+/*fixme: assumption about the following code:
+ * - there can be only one marker in a packet
+ */
+
+ /* skip the remaining bytes of a short marker */
+ i = sd->short_mark;
+ if (i != 0) {
+ sd->short_mark = 0;
+ if (i < 0 /* if 'ff' at end of previous packet */
+ && data[0] == 0xff
+ && data[1] == 0x00)
+ goto marker_found;
+ if (data[0] == 0xff && data[1] == 0xff) {
+ i = 0;
+ goto marker_found;
+ }
+ len -= i;
+ if (len <= 0)
+ return;
+ data += i;
+ }
+
+ /* search backwards if there is a marker in the packet */
+ for (i = len - 1; --i >= 0; ) {
+ if (data[i] != 0xff) {
+ i--;
+ continue;
+ }
+ if (data[i + 1] == 0xff) {
+
+ /* (there may be 'ff ff' inside a marker) */
+ if (i + 2 >= len || data[i + 2] == 0x00)
+ goto marker_found;
+ }
+ }
+
+ /* no marker found */
+ /* add the JPEG header if first fragment */
+ if (data[len - 1] == 0xff)
+ sd->short_mark = -1;
+ if (gspca_dev->last_packet_type == LAST_PACKET)