qrng.hpp

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/*
 * $Id: qrng.hpp 293 2012-12-17 20:27:36Z jdl3 $
 * Copyright (C) 2012, 2020 John D Lamb
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
 
#ifndef CCGSL_QRNG_HPP
#define CCGSL_QRNG_HPP
 
#include<new>
#include<gsl/gsl_qrng.h>
#include"exception.hpp"
 
namespace gsl {
  class qrng {
  public:
    typedef gsl_qrng_type type;
    qrng(){
      ccgsl_pointer = 0;
      count = 0; // initially nullptr will do
    }
    // Refines random access container
    // Refines assignable
    explicit qrng( type const* T, unsigned int const dimension ){
      ccgsl_pointer = gsl_qrng_alloc( T, dimension );
      // just plausibly we could allocate qrng but not count
      try { count = new size_t; } catch( std::bad_alloc& e ){
    // try to tidy up before rethrowing
    gsl_qrng_free( ccgsl_pointer );
    throw e;
      }
      *count = 1; // initially there is just one reference to ccgsl_pointer
    }
    explicit qrng( gsl_qrng* v ){
      ccgsl_pointer = v;
      // just plausibly we could fail to allocate count: no further action needed.
      count = new size_t;
      *count = 1; // initially there is just one reference to ccgsl_pointer
    }
    // copy constructor
    qrng( qrng const& v ){ ccgsl_pointer = v.ccgsl_pointer;
      count = v.count; if( count != 0 ) ++*count; }
    // assignment operator
    qrng& operator=( qrng const& v ){
      // first, possibly delete anything pointed to by this
      if( count == 0 or --*count == 0 ){
    if( ccgsl_pointer != 0 ) gsl_qrng_free( ccgsl_pointer );
    delete count;
      } // Then copy
      ccgsl_pointer = v.ccgsl_pointer; count = v.count; if( count != 0 ) ++*count; return *this;
    }
    // destructor
    ~qrng(){
      if( count == 0 or --*count == 0 ){
    // could have allocated null pointer
    if( ccgsl_pointer != 0 ) gsl_qrng_free( ccgsl_pointer );
    delete count;
      }
    }
#ifdef __GXX_EXPERIMENTAL_CXX0X__
    qrng( qrng&& v ) : ccgsl_pointer( v.ccgsl_pointer ), count( nullptr ){
      std::swap( count, v.count );
      v.ccgsl_pointer = nullptr;
    }
    qrng& operator=( qrng&& v ){
      qrng( std::move( v ) ).swap( *this );
      return *this;
    }
#endif
    // Refines equality comparable
    // == operator
    bool operator==( qrng const& v ) const { return ccgsl_pointer == v.ccgsl_pointer; }
    // != operator
    bool operator!=( qrng const& v ) const { return not operator==( v ); }
    // Refines forward container
    // Refines less than comparable
    // operator<
    bool operator<( qrng const& v ) const { return ccgsl_pointer < v.ccgsl_pointer; }
    // operator>
    bool operator>( qrng const& v ) const { return ccgsl_pointer > v.ccgsl_pointer; }
    // operator<=
    bool operator<=( qrng const& v ) const { return ccgsl_pointer <= v.ccgsl_pointer; }
    // operator>=
    bool operator>=( qrng const& v ) const { return ccgsl_pointer >= v.ccgsl_pointer; }
    bool empty() const { return ccgsl_pointer == 0; }
    // swap() --- should work even if sizes don't match
    void swap( qrng& v ){
      std::swap( ccgsl_pointer, v.ccgsl_pointer );
      std::swap( count, v.count );
    }
  private:
    gsl_qrng* ccgsl_pointer;
    size_t* count;
  public:
    // shared reference functions
    gsl_qrng* get() const { return ccgsl_pointer; }
    bool unique() const { return count != 0 and *count == 1; }
    size_t use_count() const { return count == 0 ? 0 : *count; }
#ifdef __GXX_EXPERIMENTAL_CXX0X__
    explicit
#endif
    operator bool() const { return ccgsl_pointer != 0; }
 
    int memcpy( qrng const& src ){ return gsl_qrng_memcpy( get(), src.get() ); }
 
    qrng clone() const { return qrng( gsl_qrng_clone( get() ) ); }
 
    void init(){ gsl_qrng_init( get() ); }
 
    char const* name() const { return gsl_qrng_name( get() ); }
 
    size_t size() const { return gsl_qrng_size( get() ); }
 
    void* state() const { return gsl_qrng_state( get() ); }
 
#ifndef DOXYGEN_SKIP
    int get( double x[] ) const { return gsl_qrng_get( get(), x ); }
#endif
    template<typename X>
    int get( X& x ) const {
      if(x.size() < get()->dimension)
    gsl_error( "x must have size at least as big as dimension of qrng.",
           __FILE__, __LINE__, exception::GSL_EBADLEN );
      return gsl_qrng_get( get(), x.data() );
    }
    // Types
    static type const* niederreiter_2(){ return gsl_qrng_niederreiter_2; }
    static type const* sobol(){ return gsl_qrng_sobol; }
    static type const* halton(){ return gsl_qrng_halton; }
    static type const* reversehalton(){ return gsl_qrng_reversehalton; }
    
  };
}
#endif