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by brian
clean slate |
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/**********************************************************************
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Random numbers and hashing
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(c) 1994, 1995 Innobase Oy
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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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UNIV_INLINE
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ulint
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ut_rnd_gen_next_ulint( |
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/*==================*/
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/* out: the next 'random' number */
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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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UNIV_INLINE
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ulint
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ut_rnd_gen_ulint(void); |
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/*==================*/
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/* out: the 'random' number */
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/************************************************************
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Generates a random integer from a given interval. */
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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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/* out: the 'random' number */
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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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UNIV_INLINE
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ibool
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ut_rnd_gen_ibool(void); |
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/*=================*/
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/* out: the random value */
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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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UNIV_INLINE
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ulint
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ut_hash_ulint( |
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/*==========*/
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/* out: hash value */
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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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UNIV_INLINE
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ulint
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ut_fold_ulint_pair( |
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/*===============*/
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/* out: folded value */
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ulint n1, /* in: ulint */ |
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ulint n2); /* in: ulint */ |
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/*****************************************************************
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Folds a dulint. */
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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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/* out: folded value */
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dulint d); /* in: dulint */ |
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/*****************************************************************
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Folds a character string ending in the null character. */
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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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/* out: folded value */
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const char* str); /* in: null-terminated string */ |
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/*****************************************************************
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Folds a binary string. */
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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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/* out: folded value */
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const byte* str, /* in: string of bytes */ |
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ulint len); /* in: length */ |
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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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ulint
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ut_find_prime( |
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/*==========*/
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/* out: prime */
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ulint n); /* in: positive number > 100 */ |
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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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