epoc32/include/stdapis/boost/random/uniform_int.hpp
branchSymbian2
changeset 2 2fe1408b6811
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/epoc32/include/stdapis/boost/random/uniform_int.hpp	Tue Mar 16 16:12:26 2010 +0000
     1.3 @@ -0,0 +1,152 @@
     1.4 +/* boost random/uniform_int.hpp header file
     1.5 + *
     1.6 + * Copyright Jens Maurer 2000-2001
     1.7 + * Distributed under the Boost Software License, Version 1.0. (See
     1.8 + * accompanying file LICENSE_1_0.txt or copy at
     1.9 + * http://www.boost.org/LICENSE_1_0.txt)
    1.10 + *
    1.11 + * See http://www.boost.org for most recent version including documentation.
    1.12 + *
    1.13 + * $Id: uniform_int.hpp,v 1.27 2004/07/27 03:43:32 dgregor Exp $
    1.14 + *
    1.15 + * Revision history
    1.16 + *  2001-04-08  added min<max assertion (N. Becker)
    1.17 + *  2001-02-18  moved to individual header files
    1.18 + */
    1.19 +
    1.20 +#ifndef BOOST_RANDOM_UNIFORM_INT_HPP
    1.21 +#define BOOST_RANDOM_UNIFORM_INT_HPP
    1.22 +
    1.23 +#include <cassert>
    1.24 +#include <iostream>
    1.25 +#include <boost/config.hpp>
    1.26 +#include <boost/limits.hpp>
    1.27 +#include <boost/static_assert.hpp>
    1.28 +#include <boost/detail/workaround.hpp>
    1.29 +#include <boost/random/uniform_smallint.hpp>
    1.30 +#include <boost/random/detail/signed_unsigned_compare.hpp>
    1.31 +#ifdef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
    1.32 +#include <boost/type_traits/is_float.hpp>
    1.33 +#endif
    1.34 +
    1.35 +namespace boost {
    1.36 +
    1.37 +// uniform integer distribution on [min, max]
    1.38 +template<class IntType = int>
    1.39 +class uniform_int
    1.40 +{
    1.41 +public:
    1.42 +  typedef IntType input_type;
    1.43 +  typedef IntType result_type;
    1.44 +
    1.45 +  explicit uniform_int(IntType min = 0, IntType max = 9)
    1.46 +    : _min(min), _max(max)
    1.47 +  {
    1.48 +#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
    1.49 +    // MSVC fails BOOST_STATIC_ASSERT with std::numeric_limits at class scope
    1.50 +    BOOST_STATIC_ASSERT(std::numeric_limits<IntType>::is_integer);
    1.51 +#endif
    1.52 +    assert(min <= max);
    1.53 +    init();
    1.54 +  }
    1.55 +
    1.56 +  result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return _min; }
    1.57 +  result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return _max; }
    1.58 +  void reset() { }
    1.59 +  
    1.60 +  // can't have member function templates out-of-line due to MSVC bugs
    1.61 +  template<class Engine>
    1.62 +  result_type operator()(Engine& eng)
    1.63 +  {
    1.64 +    typedef typename Engine::result_type base_result;
    1.65 +    base_result bmin = (eng.min)();
    1.66 +    base_result brange = (eng.max)() - (eng.min)();
    1.67 +
    1.68 +    if(_range == 0) {
    1.69 +      return _min;    
    1.70 +    } else if(random::equal_signed_unsigned(brange, _range)) {
    1.71 +      // this will probably never happen in real life
    1.72 +      // basically nothing to do; just take care we don't overflow / underflow
    1.73 +      return static_cast<result_type>(eng() - bmin) + _min;
    1.74 +    } else if(random::lessthan_signed_unsigned(brange, _range)) {
    1.75 +      // use rejection method to handle things like 0..3 --> 0..4
    1.76 +      for(;;) {
    1.77 +        // concatenate several invocations of the base RNG
    1.78 +        // take extra care to avoid overflows
    1.79 +        result_type limit;
    1.80 +        if(_range == (std::numeric_limits<result_type>::max)()) {
    1.81 +          limit = _range/(result_type(brange)+1);
    1.82 +          if(_range % result_type(brange)+1 == result_type(brange))
    1.83 +            ++limit;
    1.84 +        } else {
    1.85 +          limit = (_range+1)/(result_type(brange)+1);
    1.86 +        }
    1.87 +        // We consider "result" as expressed to base (brange+1):
    1.88 +        // For every power of (brange+1), we determine a random factor
    1.89 +        result_type result = result_type(0);
    1.90 +        result_type mult = result_type(1);
    1.91 +        while(mult <= limit) {
    1.92 +          result += (eng() - bmin) * mult;
    1.93 +          mult *= result_type(brange)+result_type(1);
    1.94 +        }
    1.95 +        if(mult == limit)
    1.96 +          // _range+1 is an integer power of brange+1: no rejections required
    1.97 +          return result;
    1.98 +        // _range/mult < brange+1  -> no endless loop
    1.99 +        result += uniform_int<result_type>(0, _range/mult)(eng) * mult;
   1.100 +        if(result <= _range)
   1.101 +          return result + _min;
   1.102 +      }
   1.103 +    } else {                   // brange > range
   1.104 +      if(brange / _range > 4 /* quantization_cutoff */ ) {
   1.105 +        // the new range is vastly smaller than the source range,
   1.106 +        // so quantization effects are not relevant
   1.107 +        return boost::uniform_smallint<result_type>(_min, _max)(eng);
   1.108 +      } else {
   1.109 +        // use rejection method to handle cases like 0..5 -> 0..4
   1.110 +        for(;;) {
   1.111 +          base_result result = eng() - bmin;
   1.112 +          // result and range are non-negative, and result is possibly larger
   1.113 +          // than range, so the cast is safe
   1.114 +          if(result <= static_cast<base_result>(_range))
   1.115 +            return result + _min;
   1.116 +        }
   1.117 +      }
   1.118 +    }
   1.119 +  }
   1.120 +
   1.121 +#if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
   1.122 +  template<class CharT, class Traits>
   1.123 +  friend std::basic_ostream<CharT,Traits>&
   1.124 +  operator<<(std::basic_ostream<CharT,Traits>& os, const uniform_int& ud)
   1.125 +  {
   1.126 +    os << ud._min << " " << ud._max;
   1.127 +    return os;
   1.128 +  }
   1.129 +
   1.130 +  template<class CharT, class Traits>
   1.131 +  friend std::basic_istream<CharT,Traits>&
   1.132 +  operator>>(std::basic_istream<CharT,Traits>& is, uniform_int& ud)
   1.133 +  {
   1.134 +# if BOOST_WORKAROUND(_MSC_FULL_VER, BOOST_TESTED_AT(13102292)) && BOOST_MSVC > 1300
   1.135 +      return detail::extract_uniform_int(is, ud, ud.impl);
   1.136 +# else
   1.137 +   is >> std::ws >> ud._min >> std::ws >> ud._max;
   1.138 +    ud.init();
   1.139 +    return is;
   1.140 +# endif
   1.141 +  }
   1.142 +#endif
   1.143 +
   1.144 +private:
   1.145 +  void init()
   1.146 +  {
   1.147 +    _range = _max - _min;
   1.148 +  }
   1.149 +    
   1.150 +  result_type _min, _max, _range;
   1.151 +};
   1.152 +
   1.153 +} // namespace boost
   1.154 +
   1.155 +#endif // BOOST_RANDOM_UNIFORM_INT_HPP