Import of the watch repository from Pebble

src/fw/util/crc8.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/*
+ * Calculate an 8-bit CRC of a given byte sequence. Note that this is not using the standard CRC-8
+ * polynomial, because the standard polynomial isn't very good. If the big_endian flag is set, the
+ * crc will be calculated by going through the data in reverse order (high->low index).
+ */
+uint8_t crc8_calculate_bytes(const uint8_t *data, uint32_t data_length, bool big_endian);
+void crc8_calculate_bytes_streaming(const uint8_t *data, uint32_t data_length, uint8_t *crc,
+                                    bool big_endian);