save failed integration state

gomspace/libutil/include/gs/util/crc8.h

@@ -0,0 +1,55 @@
+#ifndef GS_UTIL_CRC8_H
+#define GS_UTIL_CRC8_H
+/* Copyright (c) 2013-2017 GomSpace A/S. All rights reserved. */
+/**
+   @file
+
+   CRC8 checksumes.
+
+   https://en.wikipedia.org/wiki/Cyclic_redundancy_check.
+*/
+
+#include <gs/util/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+   Return init/seed value for CRC-8.
+   @return initial/seed value for CRC-8, using 0xff.
+   @see gs_crc8_update(), gs_crc8_finalize()
+*/
+uint8_t gs_crc8_init(void);
+
+/**
+   Update CRC-8.
+   @param[in] crc current CRC-8
+   @param[in] block start of memory block.
+   @param[in] length length of \a block.
+   @return updated CRC-8.
+   @see gs_crc8_init(), gs_crc8_finalize()
+*/
+uint8_t gs_crc8_update(uint8_t crc, const void * block, size_t length);
+
+/**
+   Return finalized CRC-8.
+   @param[in] crc Checksum is finalized by xor'ing 0xffffffff.
+   @return finalized CRC-8.
+   @see gs_crc8_init(), gs_crc8_update()
+*/
+uint8_t gs_crc8_finalize(uint8_t crc);
+
+/**
+   Return finalized CRC-8 on amemory block.
+
+   @param[in] block block to calculate CRC-8 on.
+   @param[in] length length/size of \a block.
+   @return finalized CRC-8.
+*/
+uint8_t gs_crc8(const void *block, size_t length);
+
+#ifdef __cplusplus
+}
+#endif
+#endif