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/*
* 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 __cplusplus
extern "C" {
#endif
#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 = __nl_hash(argv[1], strlen(argv[1]), 0);
* hash2 = __nl_hash(argv[2], strlen(argv[2]), 0);
* printf("Hash is %s\n", hash1 == hash2 ? "same" : "different");
* return 0;
* }
*/
#define __nl_hash(p, num, base) nl_hash_any((p), (num)*sizeof(*(p)), (base))
/* Our underlying operations. */
uint32_t nl_hash_any(const void *key, size_t length, uint32_t base);
#ifdef __cplusplus
}
#endif
#endif /* HASH_H */
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