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144 lines
4.3 KiB
C
144 lines
4.3 KiB
C
/*****************************************************************************
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Copyright (c) 1994, 2009, Innobase Oy. All Rights Reserved.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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Place, Suite 330, Boston, MA 02111-1307 USA
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*****************************************************************************/
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/******************************************************************//**
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@file include/ut0rnd.h
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Random numbers and hashing
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Created 1/20/1994 Heikki Tuuri
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***********************************************************************/
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#ifndef ut0rnd_h
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#define ut0rnd_h
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#include "univ.i"
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#include "ut0byte.h"
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/** The 'character code' for end of field or string (used
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in folding records */
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#define UT_END_OF_FIELD 257
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/********************************************************//**
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This is used to set the random number seed. */
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UNIV_INLINE
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void
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ut_rnd_set_seed(
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/*============*/
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ulint seed); /*!< in: seed */
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/********************************************************//**
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The following function generates a series of 'random' ulint integers.
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@return the next 'random' number */
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UNIV_INLINE
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ulint
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ut_rnd_gen_next_ulint(
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/*==================*/
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ulint rnd); /*!< in: the previous random number value */
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/*********************************************************//**
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The following function generates 'random' ulint integers which
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enumerate the value space (let there be N of them) of ulint integers
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in a pseudo-random fashion. Note that the same integer is repeated
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always after N calls to the generator.
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@return the 'random' number */
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UNIV_INLINE
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ulint
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ut_rnd_gen_ulint(void);
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/*==================*/
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/********************************************************//**
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Generates a random integer from a given interval.
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@return the 'random' number */
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UNIV_INLINE
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ulint
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ut_rnd_interval(
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/*============*/
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ulint low, /*!< in: low limit; can generate also this value */
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ulint high); /*!< in: high limit; can generate also this value */
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/*********************************************************//**
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Generates a random iboolean value.
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@return the random value */
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UNIV_INLINE
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ibool
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ut_rnd_gen_ibool(void);
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/*=================*/
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/*******************************************************//**
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The following function generates a hash value for a ulint integer
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to a hash table of size table_size, which should be a prime or some
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random number to work reliably.
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@return hash value */
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UNIV_INLINE
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ulint
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ut_hash_ulint(
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/*==========*/
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ulint key, /*!< in: value to be hashed */
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ulint table_size); /*!< in: hash table size */
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/*************************************************************//**
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Folds a pair of ulints.
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@return folded value */
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UNIV_INLINE
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ulint
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ut_fold_ulint_pair(
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/*===============*/
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ulint n1, /*!< in: ulint */
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ulint n2) /*!< in: ulint */
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__attribute__((const));
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/*************************************************************//**
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Folds a dulint.
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@return folded value */
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UNIV_INLINE
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ulint
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ut_fold_dulint(
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/*===========*/
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dulint d) /*!< in: dulint */
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__attribute__((const));
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/*************************************************************//**
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Folds a character string ending in the null character.
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@return folded value */
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UNIV_INLINE
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ulint
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ut_fold_string(
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/*===========*/
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const char* str) /*!< in: null-terminated string */
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__attribute__((pure));
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/*************************************************************//**
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Folds a binary string.
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@return folded value */
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UNIV_INLINE
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ulint
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ut_fold_binary(
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/*===========*/
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const byte* str, /*!< in: string of bytes */
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ulint len) /*!< in: length */
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__attribute__((pure));
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/***********************************************************//**
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Looks for a prime number slightly greater than the given argument.
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The prime is chosen so that it is not near any power of 2.
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@return prime */
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UNIV_INTERN
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ulint
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ut_find_prime(
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/*==========*/
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ulint n) /*!< in: positive number > 100 */
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__attribute__((const));
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#ifndef UNIV_NONINL
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#include "ut0rnd.ic"
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#endif
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#endif
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