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-rw-r--r--firmware/include/checksum.h41
1 files changed, 41 insertions, 0 deletions
diff --git a/firmware/include/checksum.h b/firmware/include/checksum.h
new file mode 100644
index 0000000000..6e66368bcf
--- /dev/null
+++ b/firmware/include/checksum.h
@@ -0,0 +1,41 @@
+/***************************************************************************
+ * __________ __ ___.
+ * Open \______ \ ____ ____ | | _\_ |__ _______ ___
+ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+ * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+ * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+ * \/ \/ \/ \/ \/
+ * $Id$
+ *
+ * Copyright (C) 2020 James Buren
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifndef _CHECKSUM_H
+#define _CHECKSUM_H
+
+/* rockbox firmware checksum algorithm */
+static inline uint32_t calc_checksum(uint32_t sum, const uint8_t* buf, size_t len)
+{
+ for (size_t i = 0; i < len; i++)
+ sum += buf[i];
+ return sum;
+}
+
+/* similar to above but only used for verification */
+static inline bool verify_checksum(uint32_t cs, const uint8_t* buf, size_t len)
+{
+ return (calc_checksum(MODEL_NUMBER, buf, len) == cs);
+}
+
+#endif