/usr/include/libcoyotl/prng.h is in libcoyotl-dev 3.1.0-6.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// Algorithmic Conjurings @ http://www.coyotegulch.com
//
// prng.h (libcoyotl)
//
// A Framework for Pseudorandom Number Generators
//---------------------------------------------------------------------
//
// Copyright 1990-2005 Scott Robert Ladd
//
// 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; either version 2 of the License, or
// (at your option) any later version.
//
// 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.
// 59 Temple Place - Suite 330
// Boston, MA 02111-1307, USA.
//
//-----------------------------------------------------------------------
//
// For more information on this software package, please visit
// Scott's web site, Coyote Gulch Productions, at:
//
// http://www.coyotegulch.com
//
//-----------------------------------------------------------------------
#if !defined(LIBCOYOTL_PRNG_H)
#define LIBCOYOTL_PRNG_H
// Standard C Library
#include <cstddef>
#include <cstdio>
#include <ctime>
#include <cmath>
#include <fcntl.h>
#include <stdint.h>
namespace libcoyotl
{
//! An abstract definition of a peudorandom number generator
/*!
This class defines the generic properties of any psuedo-random number
generator that returns a 32-bit unsigned result.
*/
class prng
{
protected:
//! Initialization seed
uint32_t m_seed;
public:
//! Default constructor, reading seed from/dev/urandom or the time.
/*!
The constructor initializes the prng seed from either the time
or some stochastic source such as /dev/random or /dev/urandom.
*/
prng();
//! Default constructor, with optional seed.
/*!
Starts the PRNG with a specific seed; this is provided so that
a given sequence of "random" values can be duplicated. Note that
the actual sequence is predicated on the specific PRNG algorithm.
\param seed - Seed value used to "start" or seed the generator
*/
prng(uint32_t seed);
//! Initializes the generator with "seed"
/*!
Resets the generator using the provided seed value.
\param seed - Seed value used to "start" or seed the generator
*/
virtual void init(uint32_t seed);
//! Returns the original seed value
/*!
Returns the seed value used to initialize this generator.
\return The seed value used to initialize this generator
*/
uint32_t get_seed();
//! Get the next integer
/*!
Returns the next uint32_t in sequence.
\return A pseudorandom uint32_t value
*/
virtual uint32_t get_rand() = 0;
//! Get the next integer in the range [lo,hi]
/*!
Returns the next int_value between lo and hi, inclusive.
\param lo - Minimum value of result
\param hi - Maximum value of result
\return A pseudorandom uint32_t value
*/
uint32_t get_rand_range(uint32_t lo, uint32_t hi);
//! Get the next random value as a size_t index
/*!
Returns the next value as a size_t "index" in the range [0,length).
\param length - Maximum value of result
\return A pseudorandom size_t value
*/
size_t get_rand_index(size_t length);
//! Get the next number in the range [0,1]
/*!
Returns the next real number in the range [0,1], i.e., a number
greater than or equal to 0 and less than or equal to 1.
Provides 32-bit precision.
\return A pseudorandom double value
*/
double get_rand_real1();
//! Get the next number in the range [0,1)
/*!
Returns the next real number in the range [0,1), i.e., a number
greater than or equal to 0 and less than 1.
Provides 32-bit precision.
\return A pseudorandom double value
*/
double get_rand_real2();
//! Get the next number in the range (0,1)
/*!
Returns the next real number in the range (0,1), i.e., a number
greater than 0 and less than 1.
Provides 32-bit precision.
\return A pseudorandom double value
*/
double get_rand_real3();
//! Get the next number in the range [0,1)
/*!
Returns the next real number in the range [0,1), i.e., a number
greater than or equal to 0 and less than 1.
Provides 53-bit precision.
\return A pseudorandom double value
*/
double get_rand_real53();
};
//---------------------------------------------------------------------------
// Returns the original seed value
inline uint32_t prng::get_seed()
{
return m_seed;
}
//---------------------------------------------------------------------------
// Obtain a psuedorandom integer in the range [lo,hi]
inline uint32_t prng::get_rand_range(uint32_t lo, uint32_t hi)
{
// Local working storage
double range = hi - lo + 1.0;
// Use real value to caluclate range
return lo + uint32_t(floor(range * get_rand_real2()));
}
//--------------------------------------------------------------------------
// Returns the next value as a size_t "index" in the range [0,length).
inline size_t prng::get_rand_index(size_t length)
{
return size_t(double(length) * get_rand_real2());
}
//--------------------------------------------------------------------------
// Obtain a psuedorandom real number in the range [0,1], i.e., a number
// greater than or equal to 0 and less than or equal to 1.
inline double prng::get_rand_real1()
{
// privides a granularity of approx. 2.3E-10
return double(get_rand()) * (1.0 / 4294967295.0);
}
//--------------------------------------------------------------------------
// Obtain a psuedorandom real number in the range [0,1), i.e., a number
// greater than or equal to 0 and less than 1.
inline double prng::get_rand_real2()
{
// privides a granularity of approx. 2.3E-10
return double(get_rand()) * (1.0 / 4294967296.0);
}
//--------------------------------------------------------------------------
// Obtain a psuedorandom real number in the range (0,1), i.e., a number
// greater than 0 and less than 1.
inline double prng::get_rand_real3()
{
// privides a granularity of approx. 2.3E-10
return double((double(get_rand()) + 0.5) * (1.0 / 4294967296.0));
}
} // end namespace libcoyotl
#endif
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