From bcd4cc6a8ddce7fe40512dab1304f71530121dd2 Mon Sep 17 00:00:00 2001
From: wangfq <wangfq@collectpublish.net>
Date: Wed, 27 May 2026 10:25:40 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20DG430=20=E5=8D=8F=E8=AE=AE=E6=A0=A1?=
 =?UTF-8?q?=E9=AA=8C=20off-by-one=EF=BC=8Cpayload=20=E8=8C=83=E5=9B=B4?=
 =?UTF-8?q?=E4=BF=AE=E6=AD=A3?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/dg430.py | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/dg430.py b/src/dg430.py
index 401993a..f8d2c60 100644
--- a/src/dg430.py
+++ b/src/dg430.py
@@ -65,11 +65,11 @@ def verify_packet(data: bytes) -> bool:
         return False
 
     length = data[2]
-    expected_len = 1 + 1 + 1 + length + 1 + 1  # STX + ADDR + LEN + DATA + XOR + SUM
+    expected_len = 1 + 1 + 1 + length + 1 + 1  # STX + ADDR + LEN + DATA(LEN) + XOR + SUM
     if len(data) != expected_len:
         return False
 
-    payload_end = 4 + length  # STX(1) + ADDR(1) + LEN(1) + CMD(1) + DATA(LEN-1)
+    payload_end = 3 + length  # 校验范围 [ADDR .. DATA末尾]
     actual_xor = _xor_checksum(data, 1, payload_end)
     actual_sum = _sum_checksum(data, 1, payload_end)
 
@@ -91,7 +91,7 @@ def hex_str_to_bytes(hex_str: str) -> bytes:
 def parse_b2_status(data: bytes) -> DG430Status | None:
     """解析 0xB2 状态上报包
 
-    格式: STX | ADDR | LEN(0x18=24) | 0xB2 | 20字节状态内容 | XOR | SUM
+    格式: STX | ADDR | LEN | CMD | DATA(LEN-1 bytes) | XOR | SUM
     """
     if not verify_packet(data):
         logger.warning("DG430 数据包校验失败")
@@ -103,7 +103,10 @@ def parse_b2_status(data: bytes) -> DG430Status | None:
         logger.debug(f"非 B2 指令: 0x{cmd:02X}")
         return None
 
-    payload = data[4:24]  # 20 字节状态内容
+    payload = data[4:3 + data[2]]  # DATA = LEN - 1 bytes (CMD 占位置 3)
+    if len(payload) < 20:
+        logger.warning(f"B2 数据长度不足: {len(payload)} < 20")
+        return None
 
     # 设备型号
     dev_model = payload[0]   # 1=PD132, 2=DLD110
@@ -125,9 +128,9 @@ def parse_b2_status(data: bytes) -> DG430Status | None:
     enter_dist = _le16(payload, 13)
     exit_dist = _le16(payload, 15)
 
-    # 速度 dm/s
-    enter_speed = _le16(payload, 17)
-    exit_speed = _le16(payload, 19)
+    # 速度 dm/s (V2.0.2 新增)
+    enter_speed = _le16(payload, 17) if len(payload) >= 19 else 0
+    exit_speed = _le16(payload, 19) if len(payload) >= 21 else 0
 
     return DG430Status(
         addr=addr,