AP_Math: add CRC8_generic method

ArduPilot · Jun 17, 2022 · 2dd15dd · 2dd15dd
1 parent 6a3c73b
commit 2dd15dd
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diff --git a/libraries/AP_Math/crc.cpp b/libraries/AP_Math/crc.cpp
@@ -90,6 +90,16 @@ uint8_t crc_crc8(const uint8_t *p, uint8_t len)
 	return crc & 0xFF;
 }
 
+// CRC8 that does not use a lookup table: for generic polynomials
+uint8_t crc8_generic(const uint8_t *buf, const uint16_t buf_len, const uint8_t polynomial)
+{
+    uint8_t crc = 0;
+    for (uint16_t i = 0; i < buf_len; i++) {
+        crc = crc8_dvb(buf[i], crc, polynomial);
+    }
+    return crc;
+}
+
 // crc8 from betaflight
 uint8_t crc8_dvb_s2(uint8_t crc, uint8_t a)
 {

diff --git a/libraries/AP_Math/crc.h b/libraries/AP_Math/crc.h
@@ -19,6 +19,7 @@
 
 uint16_t crc_crc4(uint16_t *data);
 uint8_t crc_crc8(const uint8_t *p, uint8_t len);
+uint8_t crc8_generic(const uint8_t *buf, const uint16_t buf_len, const uint8_t polynomial);     // CRC8 that does not use a lookup table for generic polynomials
 uint8_t crc8_dvb_s2(uint8_t crc, uint8_t a);
 uint8_t crc8_dvb(uint8_t crc, uint8_t a, uint8_t seed);
 uint8_t crc8_dvb_s2_update(uint8_t crc, const void *data, uint32_t length);