*

ODrive-fw-v0.5.6/Firmware/fibre-cpp/crc.hpp

@@ -0,0 +1,56 @@
+#ifndef __CRC_HPP
+#define __CRC_HPP
+
+#include <stdint.h>
+#include <limits.h>
+
+// Calculates an arbitrary CRC for one byte.
+// Adapted from https://barrgroup.com/Embedded-Systems/How-To/CRC-Calculation-C-Code
+template<typename T, unsigned POLYNOMIAL>
+static T calc_crc(T remainder, uint8_t value) {
+    constexpr T BIT_WIDTH = (CHAR_BIT * sizeof(T));
+    constexpr T TOPBIT = ((T)1 << (BIT_WIDTH - 1));
+    
+    // Bring the next byte into the remainder.
+    remainder ^= (value << (BIT_WIDTH - 8));
+
+    // Perform modulo-2 division, a bit at a time.
+    for (uint8_t bit = 8; bit; --bit) {
+        if (remainder & TOPBIT) {
+            remainder = (remainder << 1) ^ POLYNOMIAL;
+        } else {
+            remainder = (remainder << 1);
+        }
+    }
+
+    return remainder;
+}
+
+template<typename T, unsigned POLYNOMIAL>
+static T calc_crc(T remainder, const uint8_t* buffer, size_t length) {
+    while (length--)
+        remainder = calc_crc<T, POLYNOMIAL>(remainder, *(buffer++));
+    return remainder;
+}
+
+template<unsigned POLYNOMIAL>
+static uint8_t calc_crc8(uint8_t remainder, uint8_t value) {
+    return calc_crc<uint8_t, POLYNOMIAL>(remainder, value);
+}
+
+template<unsigned POLYNOMIAL>
+static uint16_t calc_crc16(uint16_t remainder, uint8_t value) {
+    return calc_crc<uint16_t, POLYNOMIAL>(remainder, value);
+}
+
+template<unsigned POLYNOMIAL>
+static uint8_t calc_crc8(uint8_t remainder, const uint8_t* buffer, size_t length) {
+    return calc_crc<uint8_t, POLYNOMIAL>(remainder, buffer, length);
+}
+
+template<unsigned POLYNOMIAL>
+static uint16_t calc_crc16(uint16_t remainder, const uint8_t* buffer, size_t length) {
+    return calc_crc<uint16_t, POLYNOMIAL>(remainder, buffer, length);
+}
+
+#endif /* __CRC_HPP */