-//$$CDS-header$$
+/*
+ This file is a part of libcds - Concurrent Data Structures library
+
+ (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 2006-2017
+
+ Source code repo: http://github.com/khizmax/libcds/
+ Download: http://sourceforge.net/projects/libcds/files/
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice, this
+ list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+ this list of conditions and the following disclaimer in the documentation
+ and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
#ifndef CDSLIB_OPT_PERMUTATION_H
#define CDSLIB_OPT_PERMUTATION_H
-#include <stdlib.h> // rand, srand
+#include <cstdlib> // rand, srand
#include <random>
#include <algorithm> // std::shuffle
+#include <numeric> // std::iota
#include <cds/opt/options.h>
};
\endcode
- Usage example:
+ <b>Usage example</b>
+
The permutation generator is intended for <tt>do {} while</tt> loop:
\code
permutation_generator gen( 16 );
do {
int i = gen;
//...
- } while ( gen.next() );
+ } while ( gen.next());
// Get other permutation
gen.reset();
do {
int i = gen;
//...
- } while ( gen.next() );
+ } while ( gen.next());
\endcode
The following \p Generator defined:
- - opt::v::random_permutation
- - opt::v::random2_permutation
- - opt::v::random_shuffle_permutation
- - opt::v::skew_permutation
+ - \p opt::v::random_permutation
+ - \p opt::v::random2_permutation
+ - \p opt::v::random_shuffle_permutation
+ - \p opt::v::skew_permutation
*/
template <typename Generator>
struct permutation_generator {
random_permutation( size_t nLength )
: m_nCur(0)
, m_nStart(0)
- , m_nMod( integer_type(nLength) )
+ , m_nMod( integer_type(nLength))
{
reset();
}
/// Resets the generator to produce new sequence
void reset()
{
- m_nCur = m_nStart = integer_type( rand() ) % m_nMod;
+ m_nCur = m_nStart = integer_type( std::rand()) % m_nMod;
}
};
/// Resets the generator to produce new sequence
void reset()
{
- m_nCur = m_nStart = integer_type( rand() ) & m_nMask;
+ m_nCur = m_nStart = integer_type( std::rand()) & m_nMask;
}
};
integer_type * m_pCur;
integer_type * m_pFirst;
integer_type * m_pLast;
-
- random_generator m_RandomGenerator;
//@endcond
public:
/// Initializes the generator of arbitrary length \p nLength
random_shuffle_permutation( size_t nLength )
: m_pCur( nullptr )
- , m_RandomGenerator( random_device()() )
{
m_pFirst = new integer_type[nLength];
m_pLast = m_pFirst + nLength;
- for ( integer_type i = 0; i < static_cast<integer_type>(nLength); ++i )
- m_pFirst[i] = i;
+ std::iota(m_pFirst, m_pLast, integer_type{0} );
reset();
}
/// Resets the generator to produce new sequence
void reset()
{
- std::shuffle( m_pFirst, m_pLast, m_RandomGenerator );
+ std::shuffle( m_pFirst, m_pLast, random_generator{ random_device{}() });
m_pCur = m_pFirst;
}
};