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/** @file include/ut0rnd.h
 Random numbers and hashing

 Created 1/20/1994 Heikki Tuuri
 ***********************************************************************/

#ifndef ut0rnd_h
#define ut0rnd_h

#include "univ.i"
#include "ut0byte.h"

/** The 'character code' for end of field or string (used
in folding records */
#define UT_END_OF_FIELD 257

/** The following function generates a series of 'random' ulint integers.
 @return the next 'random' number */
UNIV_INLINE
ulint ut_rnd_gen_next_ulint(
    ulint rnd); /*!< in: the previous random number value */
/** The following function generates 'random' ulint integers which
 enumerate the value space (let there be N of them) of ulint integers
 in a pseudo-random fashion. Note that the same integer is repeated
 always after N calls to the generator.
 @return the 'random' number */
UNIV_INLINE
ulint ut_rnd_gen_ulint(void);

/** Generates a random integer from a given interval.
@param[in]	low	low limit; can generate also this value
@param[in]	high	high limit; can generate also this value
@return the 'random' number */
UNIV_INLINE
ulint ut_rnd_interval(ulint low, ulint high);

/** The following function generates a hash value for a ulint integer to a
hash table of size table_size, which should be a prime or some random number
to work reliably.
@param[in]	key		value to be hashed
@param[in]	table_size	hash table size
@return hash value */
UNIV_INLINE
ulint ut_hash_ulint(ulint key, ulint table_size);

/** Folds a 64-bit integer.
 @return folded value */
UNIV_INLINE
ulint ut_fold_ull(ib_uint64_t d) /*!< in: 64-bit integer */
    MY_ATTRIBUTE((const));
/** Folds a character string ending in the null character.
 @return folded value */
UNIV_INLINE
ulint ut_fold_string(const char *str) /*!< in: null-terminated string */
    MY_ATTRIBUTE((warn_unused_result));
/** Looks for a prime number slightly greater than the given argument.
 The prime is chosen so that it is not near any power of 2.
 @return prime */
ulint ut_find_prime(ulint n) /*!< in: positive number > 100 */
    MY_ATTRIBUTE((const));

/** Folds a pair of ulints.
 @return folded value */
UNIV_INLINE
ulint ut_fold_ulint_pair(ulint n1, /*!< in: ulint */
                         ulint n2) /*!< in: ulint */
    MY_ATTRIBUTE((const));
/** Folds a binary string.
 @return folded value */
UNIV_INLINE
ulint ut_fold_binary(const byte *str, /*!< in: string of bytes */
                     ulint len)       /*!< in: length */
    MY_ATTRIBUTE((pure));

#include "ut0rnd.ic"

#endif