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168 lines
4.2 KiB
C++
168 lines
4.2 KiB
C++
//
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// Random.h
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//
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// $Id: //poco/1.4/Foundation/include/Poco/Random.h#1 $
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//
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// Library: Foundation
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// Package: Crypt
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// Module: Random
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//
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// Definition of class Random.
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//
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// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// SPDX-License-Identifier: BSL-1.0
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//
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//
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// Based on the FreeBSD random number generator.
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// src/lib/libc/stdlib/random.c,v 1.25
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//
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// Copyright (c) 1983, 1993
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// The Regents of the University of California. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions
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// are met:
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// 1. Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution.
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// 4. Neither the name of the University nor the names of its contributors
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// may be used to endorse or promote products derived from this software
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// without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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// SUCH DAMAGE.
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//
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#ifndef Foundation_Random_INCLUDED
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#define Foundation_Random_INCLUDED
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#include "Poco/Foundation.h"
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namespace Poco {
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class Foundation_API Random
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/// A better random number generator.
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/// Random implements a pseudo random number generator
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/// (PRNG). The PRNG is a nonlinear additive
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/// feedback random number generator using 256 bytes
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/// of state information and a period of up to 2^69.
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{
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public:
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enum Type
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{
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RND_STATE_0 = 8, /// linear congruential
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RND_STATE_32 = 32, /// x**7 + x**3 + 1
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RND_STATE_64 = 64, /// x**15 + x + 1
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RND_STATE_128 = 128, /// x**31 + x**3 + 1
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RND_STATE_256 = 256 /// x**63 + x + 1
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};
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Random(int stateSize = 256);
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/// Creates and initializes the PRNG.
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/// Specify either a state buffer size
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/// (8 to 256 bytes) or one of the Type values.
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~Random();
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/// Destroys the PRNG.
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void seed(UInt32 seed);
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/// Seeds the pseudo random generator with the given seed.
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void seed();
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/// Seeds the pseudo random generator with a random seed
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/// obtained from a RandomInputStream.
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UInt32 next();
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/// Returns the next 31-bit pseudo random number.
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UInt32 next(UInt32 n);
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/// Returns the next 31-bit pseudo random number modulo n.
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char nextChar();
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/// Returns the next pseudo random character.
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bool nextBool();
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/// Returns the next boolean pseudo random value.
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float nextFloat();
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/// Returns the next float pseudo random number between 0.0 and 1.0.
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double nextDouble();
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/// Returns the next double pseudo random number between 0.0 and 1.0.
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protected:
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void initState(UInt32 seed, char* arg_state, Int32 n);
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static UInt32 goodRand(Int32 x);
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private:
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enum
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{
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MAX_TYPES = 5,
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NSHUFF = 50
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};
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UInt32* _fptr;
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UInt32* _rptr;
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UInt32* _state;
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int _randType;
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int _randDeg;
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int _randSep;
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UInt32* _endPtr;
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char* _pBuffer;
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};
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//
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// inlines
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//
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inline UInt32 Random::next(UInt32 n)
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{
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return next() % n;
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}
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inline char Random::nextChar()
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{
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return char((next() >> 3) & 0xFF);
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}
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inline bool Random::nextBool()
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{
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return (next() & 0x1000) != 0;
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}
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inline float Random::nextFloat()
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{
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return float(next()) / 0x7FFFFFFF;
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}
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inline double Random::nextDouble()
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{
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return double(next()) / 0x7FFFFFFF;
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}
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} // namespace Poco
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#endif // Foundation_Random_INCLUDED
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