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+/*****************************************************************************
+
+Copyright (c) 1994, 2016, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2019, 2020, MariaDB Corporation.
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free Software
+Foundation; version 2 of the License.
+
+This program is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
+
+*****************************************************************************/
+
+/******************************************************************//**
+@file include/ut0rnd.h
+Random numbers and hashing
+
+Created 1/20/1994 Heikki Tuuri
+***********************************************************************/
+
+#ifndef ut0rnd_h
+#define ut0rnd_h
+
+#include "ut0byte.h"
+#include <my_sys.h>
+
+#ifndef UNIV_INNOCHECKSUM
+/** Seed value of ut_rnd_gen() */
+extern std::atomic<uint32_t> ut_rnd_current;
+
+/** @return a pseudo-random 32-bit number */
+inline uint32_t ut_rnd_gen()
+{
+  /* This is a Galois linear-feedback shift register.
+  https://en.wikipedia.org/wiki/Linear-feedback_shift_register#Galois_LFSRs
+  The generating primitive Galois Field polynomial is the Castagnoli
+  polynomial that was made popular by CRC-32C:
+  x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+
+  x^19+x^18+x^14+x^13+x^11+x^10+x^9+x^8+x^6+1 */
+  const uint32_t crc32c= 0x1edc6f41;
+
+  uint32_t rnd= ut_rnd_current.load(std::memory_order_relaxed);
+
+  if (UNIV_UNLIKELY(rnd == 0))
+  {
+    rnd= static_cast<uint32_t>(my_interval_timer());
+    if (!rnd) rnd= 1;
+  }
+  else
+  {
+    bool lsb= rnd & 1;
+    rnd>>= 1;
+    if (lsb)
+      rnd^= crc32c;
+  }
+
+  ut_rnd_current.store(rnd, std::memory_order_relaxed);
+  return rnd;
+}
+
+/** @return a random number between 0 and n-1, inclusive */
+inline ulint ut_rnd_interval(ulint n)
+{
+  return n > 1 ? static_cast<ulint>(ut_rnd_gen() % n) : 0;
+}
+
+/*******************************************************//**
+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.
+@return hash value */
+UNIV_INLINE
+ulint
+ut_hash_ulint(
+/*==========*/
+	ulint	 key,		/*!< in: value to be hashed */
+	ulint	 table_size);	/*!< in: hash 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));
+
+#endif /* !UNIV_INNOCHECKSUM */
+
+/*************************************************************//**
+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