From 4a0f1826446c5e12827d0b92a01adb34950262a9 Mon Sep 17 00:00:00 2001
From: sakumisu <1203593632@qq.com>
Date: Thu, 6 Oct 2022 16:24:08 +0800
Subject: [PATCH] do not reset bufoffset when len=0 or len=buf[0]

---
 class/video/usbh_video.c | 42 +++++++++++++++-------------------------
 1 file changed, 16 insertions(+), 26 deletions(-)

diff --git a/class/video/usbh_video.c b/class/video/usbh_video.c
index 14fd3786..a8c1cd23 100644
--- a/class/video/usbh_video.c
+++ b/class/video/usbh_video.c
@@ -422,23 +422,18 @@ void usbh_videostreaming_parse_mjpeg(struct usbh_urb *urb, struct usbh_videostre
             uint8_t errorBit             : 1U;
             uint8_t endOfHeader          : 1U;
         */
-        if (iso_packet[i].actual_length == 0) { /* skip */
-            stream->bufoffset = 0;
+        if (iso_packet[i].actual_length == 0) { /* skip no data */
             continue;
         }
-        if (iso_packet[i].actual_length < iso_packet[i].transfer_buffer[0]) {
-            stream->bufoffset = 0;
-            continue;
+        if (iso_packet[i].actual_length < iso_packet[i].transfer_buffer[0]) { /* do not be illegal */
+            while (1) {
+            }
         }
-        if ((iso_packet[i].transfer_buffer[0] > 12) || (iso_packet[i].transfer_buffer[0] == 0)) {
-            stream->bufoffset = 0;
-            continue;
+        if ((iso_packet[i].transfer_buffer[0] > 12) || (iso_packet[i].transfer_buffer[0] == 0)) { /* do not be illegal */
+            while (1) {
+            }
         }
-        if (iso_packet[i].transfer_buffer[1] & (1 << 6)) {
-            stream->bufoffset = 0;
-            continue;
-        }
-        if (iso_packet[i].actual_length == iso_packet[i].transfer_buffer[0]) { /* skip frame header */
+        if (iso_packet[i].transfer_buffer[1] & (1 << 6)) { /* error bit, re-receive */
             stream->bufoffset = 0;
             continue;
         }
@@ -491,23 +486,18 @@ void usbh_videostreaming_parse_yuyv2rgb565(struct usbh_urb *urb, struct usbh_vid
             uint8_t endOfHeader          : 1U;
         */
 
-        if (iso_packet[i].actual_length == 0) { /* skip */
-            stream->bufoffset = 0;
+        if (iso_packet[i].actual_length == 0) { /* skip no data */
             continue;
         }
-        if (iso_packet[i].actual_length < iso_packet[i].transfer_buffer[0]) {
-            stream->bufoffset = 0;
-            continue;
+        if (iso_packet[i].actual_length < iso_packet[i].transfer_buffer[0]) { /* do not be illegal */
+            while (1) {
+            }
         }
-        if ((iso_packet[i].transfer_buffer[0] > 12) || (iso_packet[i].transfer_buffer[0] == 0)) {
-            stream->bufoffset = 0;
-            continue;
+        if ((iso_packet[i].transfer_buffer[0] > 12) || (iso_packet[i].transfer_buffer[0] == 0)) { /* do not be illegal */
+            while (1) {
+            }
         }
-        if (iso_packet[i].transfer_buffer[1] & (1 << 6)) {
-            stream->bufoffset = 0;
-            continue;
-        }
-        if (iso_packet[i].actual_length == iso_packet[i].transfer_buffer[0]) { /* skip frame header */
+        if (iso_packet[i].transfer_buffer[1] & (1 << 6)) { /* error bit, re-receive */
             stream->bufoffset = 0;
             continue;
         }