1 files changed, 69 insertions, 0 deletions
diff --git a/include/netlink/hash.h b/include/netlink/hash.h
new file mode 100644
index 0000000..8ca1f5b
--- /dev/null
+++ b/include/netlink/hash.h
@@ -0,0 +1,69 @@
+/*
+ * This file was taken from http://ccodearchive.net/info/hash.html
+ * Changes to the original file include cleanups and removal of unwanted code
+ * and also code that depended on build_asert
+ */
+#ifndef CCAN_HASH_H
+#define CCAN_HASH_H
+#include <stdint.h>
+#include <stdlib.h>
+#include <endian.h>
+
+/* Stolen mostly from: lookup3.c, by Bob Jenkins, May 2006, Public Domain.
+ *
+ * http://burtleburtle.net/bob/c/lookup3.c
+ */
+
+#ifdef __LITTLE_ENDIAN
+#   define HAVE_LITTLE_ENDIAN 1
+#elif __BIG_ENDIAN
+#   define HAVE_BIG_ENDIAN 1
+#else
+#error Unknown endianness.  Failure in endian.h
+#endif
+
+/**
+ * hash - fast hash of an array for internal use
+ * @p: the array or pointer to first element
+ * @num: the number of elements to hash
+ * @base: the base number to roll into the hash (usually 0)
+ *
+ * The memory region pointed to by p is combined with the base to form
+ * a 32-bit hash.
+ *
+ * This hash will have different results on different machines, so is
+ * only useful for internal hashes (ie. not hashes sent across the
+ * network or saved to disk).
+ *
+ * It may also change with future versions: it could even detect at runtime
+ * what the fastest hash to use is.
+ *
+ * See also: hash64, hash_stable.
+ *
+ * Example:
+ *	#include <ccan/hash/hash.h>
+ *	#include <err.h>
+ *	#include <stdio.h>
+ *	#include <string.h>
+ *
+ *	// Simple demonstration: idential strings will have the same hash, but
+ *	// two different strings will probably not.
+ *	int main(int argc, char *argv[])
+ *	{
+ *		uint32_t hash1, hash2;
+ *
+ *		if (argc != 3)
+ *			err(1, "Usage: %s <string1> <string2>", argv[0]);
+ *
+ *		hash1 = hash(argv[1], strlen(argv[1]), 0);
+ *		hash2 = hash(argv[2], strlen(argv[2]), 0);
+ *		printf("Hash is %s\n", hash1 == hash2 ? "same" : "different");
+ *		return 0;
+ *	}
+ */
+#define hash(p, num, base) hash_any((p), (num)*sizeof(*(p)), (base))
+
+/* Our underlying operations. */
+uint32_t hash_any(const void *key, size_t length, uint32_t base);
+
+#endif /* HASH_H */