- /**********************************************************************
- Random numbers and hashing
- (c) 1994, 1995 Innobase Oy
- 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
- /************************************************************
- This is used to set the random number seed. */
- UNIV_INLINE
- void
- ut_rnd_set_seed(
- /*============*/
- ulint seed); /* in: seed */
- /************************************************************
- The following function generates a series of 'random' ulint integers. */
- UNIV_INLINE
- ulint
- ut_rnd_gen_next_ulint(
- /*==================*/
- /* out: the next 'random' number */
- 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. */
- UNIV_INLINE
- ulint
- ut_rnd_gen_ulint(void);
- /*==================*/
- /* out: the 'random' number */
- /************************************************************
- Generates a random integer from a given interval. */
- UNIV_INLINE
- ulint
- ut_rnd_interval(
- /*============*/
- /* out: the 'random' number */
- ulint low, /* in: low limit; can generate also this value */
- ulint high); /* in: high limit; can generate also this value */
- /*************************************************************
- Generates a random iboolean value. */
- UNIV_INLINE
- ibool
- ut_rnd_gen_ibool(void);
- /*=================*/
- /* out: the random value */
- /***********************************************************
- 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. */
- UNIV_INLINE
- ulint
- ut_hash_ulint(
- /*=========*/
- /* out: hash value */
- ulint key, /* in: value to be hashed */
- ulint table_size); /* in: hash table size */
- /*****************************************************************
- Folds a pair of ulints. */
- UNIV_INLINE
- ulint
- ut_fold_ulint_pair(
- /*===============*/
- /* out: folded value */
- ulint n1, /* in: ulint */
- ulint n2); /* in: ulint */
- /*****************************************************************
- Folds a dulint. */
- UNIV_INLINE
- ulint
- ut_fold_dulint(
- /*===========*/
- /* out: folded value */
- dulint d); /* in: dulint */
- /*****************************************************************
- Folds a character string ending in the null character. */
- UNIV_INLINE
- ulint
- ut_fold_string(
- /*===========*/
- /* out: folded value */
- const char* str); /* in: null-terminated string */
- /*****************************************************************
- Folds a binary string. */
- UNIV_INLINE
- ulint
- ut_fold_binary(
- /*===========*/
- /* out: folded value */
- const byte* str, /* in: string of bytes */
- ulint len); /* in: length */
- /***************************************************************
- 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. */
- ulint
- ut_find_prime(
- /*==========*/
- /* out: prime */
- ulint n); /* in: positive number > 100 */
- #ifndef UNIV_NONINL
- #include "ut0rnd.ic"
- #endif
- #endif