New upstream release.

1 files changed, 104 insertions, 0 deletions

diff --git a/crc32c.c b/crc32c.c
new file mode 100644
index 00000000..156cba19
--- /dev/null
+++ b/crc32c.c
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+/*
+ * Oct 28, 2015 Song Liu simplified the code and port it to mdadm
+ *
+ * Aug 8, 2011 Bob Pearson with help from Joakim Tjernlund and George Spelvin
+ * cleaned up code to current version of sparse and added the slicing-by-8
+ * algorithm to the closely similar existing slicing-by-4 algorithm.
+ *
+ * Oct 15, 2000 Matt Domsch <Matt_Domsch@dell.com>
+ * Nicer crc32 functions/docs submitted by linux@horizon.com.  Thanks!
+ * Code was from the public domain, copyright abandoned.  Code was
+ * subsequently included in the kernel, thus was re-licensed under the
+ * GNU GPL v2.
+ *
+ * Oct 12, 2000 Matt Domsch <Matt_Domsch@dell.com>
+ * Same crc32 function was used in 5 other places in the kernel.
+ * I made one version, and deleted the others.
+ * There are various incantations of crc32().  Some use a seed of 0 or ~0.
+ * Some xor at the end with ~0.  The generic crc32() function takes
+ * seed as an argument, and doesn't xor at the end.  Then individual
+ * users can do whatever they need.
+ *   drivers/net/smc9194.c uses seed ~0, doesn't xor with ~0.
+ *   fs/jffs2 uses seed 0, doesn't xor with ~0.
+ *   fs/partitions/efi.c uses seed ~0, xor's with ~0.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2.  See the file COPYING for more details.
+ */
+
+#include <sys/types.h>
+#include <asm/types.h>
+#include <stdlib.h>
+
+/*
+ * There are multiple 16-bit CRC polynomials in common use, but this is
+ * *the* standard CRC-32 polynomial, first popularized by Ethernet.
+ * x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0
+ */
+#define CRCPOLY_LE 0xedb88320
+#define CRCPOLY_BE 0x04c11db7
+
+/*
+ * This is the CRC32c polynomial, as outlined by Castagnoli.
+ * x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+
+ * x^8+x^6+x^0
+ */
+#define CRC32C_POLY_LE 0x82F63B78
+
+/**
+ * crc32_le_generic() - Calculate bitwise little-endian Ethernet AUTODIN II
+ *			CRC32/CRC32C
+ * @crc: seed value for computation.  ~0 for Ethernet, sometimes 0 for other
+ *	 uses, or the previous crc32/crc32c value if computing incrementally.
+ * @p: pointer to buffer over which CRC32/CRC32C is run
+ * @len: length of buffer @p
+ * @polynomial: CRC32/CRC32c LE polynomial
+ */
+static inline __u32 crc32_le_generic(__u32 crc, unsigned char const *p,
+				     size_t len, __u32 polynomial)
+{
+	int i;
+	while (len--) {
+		crc ^= *p++;
+		for (i = 0; i < 8; i++)
+			crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0);
+	}
+	return crc;
+}
+
+__u32 crc32_le(__u32 crc, unsigned char const *p, size_t len)
+{
+	return crc32_le_generic(crc, p, len, CRCPOLY_LE);
+}
+
+__u32 crc32c_le(__u32 crc, unsigned char const *p, size_t len)
+{
+	return crc32_le_generic(crc, p, len, CRC32C_POLY_LE);
+}
+
+/**
+ * crc32_be_generic() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32
+ * @crc: seed value for computation.  ~0 for Ethernet, sometimes 0 for
+ *	other uses, or the previous crc32 value if computing incrementally.
+ * @p: pointer to buffer over which CRC32 is run
+ * @len: length of buffer @p
+ * @polynomial: CRC32 BE polynomial
+ */
+static inline __u32 crc32_be_generic(__u32 crc, unsigned char const *p,
+				     size_t len, __u32 polynomial)
+{
+	int i;
+	while (len--) {
+		crc ^= *p++ << 24;
+		for (i = 0; i < 8; i++)
+			crc =
+			    (crc << 1) ^ ((crc & 0x80000000) ? polynomial :
+					  0);
+	}
+	return crc;
+}
+
+__u32 crc32_be(__u32 crc, unsigned char const *p, size_t len)
+{
+	return crc32_be_generic(crc, p, len, CRCPOLY_BE);
+}