helper: Add generic little endian CRC32 function

[openocd.git] / src / helper / crc32.h

diff --git a/src/helper/crc32.h b/src/helper/crc32.h
new file mode 100644 (file)
index 0000000..8f07786
--- /dev/null
+++ b/src/helper/crc32.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/***************************************************************************
+ *   Copyright (C) 2022 Otto-von-Guericke-Universität Magdeburg            *
+ *   marian.buschsieweke@ovgu.de                                           *
+ ***************************************************************************/
+
+#ifndef OPENOCD_HELPER_CRC32_H
+#define OPENOCD_HELPER_CRC32_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+/** @file
+ * A generic CRC32 implementation
+ */
+
+/**
+ * CRC32 polynomial commonly used for little endian CRC32
+ */
+#define CRC32_POLY_LE  0xedb88320
+
+/**
+ * Calculate the CRC32 value of the given data
+ * @param      poly            The polynomial of the CRC
+ * @param      seed            The seed to use (mostly either `0` or `0xffffffff`)
+ * @param      data            The data to calculate the CRC32 of
+ * @param      data_len        The length of the data in @p data in bytes
+ * @return     The CRC value of the first @p data_len bytes at @p data
+ * @note       This function can be used to incrementally compute the CRC one
+ *                     chunk of data at a time by using the CRC32 of the previous chunk
+ *                     as @p seed for the next chunk.
+ */
+uint32_t crc32_le(uint32_t poly, uint32_t seed, const void *data,
+               size_t data_len);
+
+#endif /* OPENOCD_HELPER_CRC32_H */