From 276ee86f38f5b736de5277eaf563813a1c866710 Mon Sep 17 00:00:00 2001
From: rishabsingh3003 <rishabh.singh100358@gmail.com>
Date: Mon, 25 Dec 2023 21:55:26 +0530
Subject: [PATCH] AP_Math: Add RDS02UF RangeFinder CRC

---
 libraries/AP_Math/crc.cpp | 45 +++++++++++++++++++++++++++++++++++++++
 libraries/AP_Math/crc.h   |  3 ++-
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_Math/crc.cpp b/libraries/AP_Math/crc.cpp
index de81543b48..244cd31496 100644
--- a/libraries/AP_Math/crc.cpp
+++ b/libraries/AP_Math/crc.cpp
@@ -227,6 +227,51 @@ uint8_t crc8_sae(const uint8_t *data, uint16_t length)
     return	crc;
 }
 
+// crc table for rangefinder rds02uf
+static const uint8_t crc8_table_rds02uf[256] = {
+    0x93,0x98,0xE4,0x46,0xEB,0xBA,0x04,0x4C,
+    0xFA,0x40,0xB8,0x96,0x0E,0xB2,0xB7,0xC0,
+    0x0C,0x32,0x9B,0x80,0xFF,0x30,0x7F,0x9D,
+    0xB3,0x81,0x58,0xE7,0xF1,0x19,0x7E,0xB6,
+    0xCD,0xF7,0xB4,0xCB,0xBC,0x5C,0xD6,0x09,
+    0x20,0x0A,0xE0,0x37,0x51,0x67,0x24,0x95,
+    0xE1,0x62,0xF8,0x5E,0x38,0x15,0x54,0x77,
+    0x63,0x57,0x6D,0xE9,0x89,0x76,0xBE,0x41,
+    0x5D,0xF9,0xB1,0x4D,0x6C,0x53,0x9C,0xA2,
+    0x23,0xC4,0x8E,0xC8,0x05,0x42,0x61,0x71,
+    0xC5,0x00,0x18,0x6F,0x5F,0xFB,0x7B,0x11,
+    0x65,0x2D,0x8C,0xED,0x14,0xAB,0x88,0xD5,
+    0xD9,0xC2,0x36,0x34,0x7C,0x5B,0x3C,0xF6,
+    0x48,0x0B,0xEE,0x02,0x83,0x79,0x17,0xE6,
+    0xA8,0x78,0xF5,0xD3,0x4E,0x50,0x52,0x91,
+    0xD8,0xC6,0x22,0xEC,0x3B,0xE5,0x3F,0x86,
+    0x06,0xCF,0x2B,0x2F,0x3D,0x59,0x1C,0x87,
+    0xEF,0x4F,0x10,0xD2,0x7D,0xDA,0x72,0xA0,
+    0x9F,0xDE,0x6B,0x75,0x56,0xBD,0xC7,0xC1,
+    0x70,0x1D,0x25,0x92,0xA5,0x31,0xE2,0xD7,
+    0xD0,0x9A,0xAF,0xA9,0xC9,0x97,0x08,0x33,
+    0x5A,0x99,0xC3,0x16,0x84,0x82,0x8A,0xF3,
+    0x4A,0xCE,0xDB,0x29,0x0F,0xAE,0x6E,0xE3,
+    0x8B,0x07,0x3A,0x74,0x47,0xB0,0xBB,0xB5,
+    0x7A,0xAA,0x2C,0xD4,0x03,0x3E,0x1A,0xA7,
+    0x27,0x64,0x06,0xBF,0x55,0x73,0x1E,0xFE,
+    0x49,0x01,0x39,0x28,0xF4,0x26,0xDF,0xDD,
+    0x44,0x0D,0x21,0xF2,0x85,0xB9,0xEA,0x4B,
+    0xDC,0x6A,0xCA,0xAC,0x12,0xFC,0x2E,0x2A,
+    0xA3,0xF0,0x66,0xE8,0x60,0x45,0xA1,0x8D,
+    0x68,0x35,0xFD,0x8F,0x9E,0x1F,0x13,0xD1,
+    0xAD,0x69,0xCC,0xA4,0x94,0x90,0x1B,0x43,
+};
+
+uint8_t crc8_rds02uf(const uint8_t *data, uint16_t length)
+{
+    uint8_t crc = 0;
+    while (length--) {
+        crc = crc8_table_rds02uf[crc^*(data++)];
+    }
+    return crc;
+}
+
 /*
   xmodem CRC thanks to avr-liberty
   https://github.com/dreamiurg/avr-liberty
diff --git a/libraries/AP_Math/crc.h b/libraries/AP_Math/crc.h
index 5aa39e70a8..1c6ef78835 100644
--- a/libraries/AP_Math/crc.h
+++ b/libraries/AP_Math/crc.h
@@ -13,7 +13,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 /*
-  interfaces to ArduPilot collection of CRCs. 
+  interfaces to ArduPilot collection of CRCs.
  */
 #pragma once
 
@@ -28,6 +28,7 @@ uint8_t crc8_dvb_s2_update(uint8_t crc, const void *data, uint32_t length);
 uint8_t crc8_dvb_update(uint8_t crc, const uint8_t* buf, const uint16_t buf_len);
 uint8_t crc8_maxim(const uint8_t *data, uint16_t length);
 uint8_t crc8_sae(const uint8_t *data, uint16_t length);
+uint8_t crc8_rds02uf(const uint8_t *data, uint16_t length);
 uint16_t crc_xmodem_update(uint16_t crc, uint8_t data);
 uint16_t crc_xmodem(const uint8_t *data, uint16_t len);
 uint32_t crc_crc32(uint32_t crc, const uint8_t *buf, uint32_t size);