ceph/src/boost/libs/poly_collection/example/segmented_structure.cpp

   1 /* Copyright 2016-2017 Joaquin M Lopez Munoz.
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * See http://www.boost.org/libs/poly_collection for library home page.
   7  */
   8
   9 /* segment-specific operations */
  10
  11 #include <algorithm>
  12 #include <boost/poly_collection/any_collection.hpp>
  13 #include <boost/poly_collection/base_collection.hpp>
  14 #include <boost/type_erasure/operators.hpp>
  15 #include <memory>
  16 #include <random>
  17 #include "rolegame.hpp"
  18
  19 std::ostream& operator<<(std::ostream& os,const sprite& s)
  20 {
  21   s.render(os);
  22   return os;
  23 }
  24
  25 std::ostream& operator<<(std::ostream& os,const window& w)
  26 {
  27   w.display(os);
  28   return os;
  29 }
  30
  31 int main()
  32 {
  33   boost::base_collection<sprite> c;
  34
  35 //[segmented_structure_1
  36 //=  std::unique_ptr<sprite> make_sprite()
  37 //=  {
  38 //<-
  39   auto make_sprite=[]()->std::unique_ptr<sprite>{
  40 //->
  41     static std::mt19937                 gen{92748};
  42     static std::discrete_distribution<> rnd{{1,1,1}};
  43     static int                          id=0;
  44
  45     switch(rnd(gen)){
  46 //<-
  47       default:
  48 //->
  49       case 0: return std::make_unique<warrior>(id++);break;
  50       case 1: return std::make_unique<juggernaut>(id++);break;
  51       case 2: return std::make_unique<goblin>(id++);break;
  52     }
  53 //<-
  54   };
  55 //->
  56 //=  }
  57 //=  ...
  58 //=
  59 //<-
  60   try{
  61 //->
  62   for(int i=0;i<8;++i)c.insert(*make_sprite());
  63   // throws boost::poly_collection::unregistered_type
  64 //<-
  65   }catch(boost::poly_collection::unregistered_type&){}
  66 //->
  67 //]
  68
  69 //[segmented_structure_2
  70   std::cout<<c.is_registered<warrior>()<<"\n";       // prints 0
  71   std::cout<<c.is_registered(typeid(warrior))<<"\n"; // alternate syntax
  72 //]
  73
  74 //[segmented_structure_3
  75   c.register_types<warrior,juggernaut,goblin>();
  76   // everything works fine now
  77   for(int i=0;i<8;++i)c.insert(*make_sprite());
  78 //]
  79
  80   using renderable=boost::type_erasure::ostreamable<>;
  81 //[segmented_structure_4
  82   boost::any_collection<renderable> c1,c2;
  83 //=  ... // populate c2
  84 //=
  85 //<-
  86   c2.insert(window{"pop-up"});
  87   try{
  88 //->
  89   c1.insert(*c2.begin()); // throws: actual type of *c2.begin() not known by c1
  90 //<-
  91   }catch(boost::poly_collection::unregistered_type&){}
  92 //->
  93 //]
  94
  95 //[segmented_structure_5
  96 //=  ... // populate c with 8 assorted entities
  97 //=
  98   std::cout<<c.size()<<"\n";                    // 8 sprites
  99   std::cout<<c.size<juggernaut>()<<"\n";        // 2 juggernauts
 100   std::cout<<c.size(typeid(juggernaut))<<"\n";  // alternate syntax
 101   c.clear<juggernaut>();                        // remove juggenauts only
 102   std::cout<<c.empty<juggernaut>()<<"\n";       // 1 (no juggernauts left)
 103   std::cout<<c.size()<<"\n";                    // 6 sprites remaining
 104 //]
 105
 106 //[segmented_structure_6
 107   const char* comma="";
 108   for(auto first=c.begin(typeid(warrior)),last=c.end(typeid(warrior));
 109       first!=last;++first){
 110     std::cout<<comma;
 111     first->render(std::cout);
 112     comma=",";
 113   }
 114   std::cout<<"\n";
 115 //]
 116
 117 //[segmented_structure_7
 118   /*=const char**/ comma="";
 119   for(const auto& x:c.segment(typeid(warrior))){
 120     std::cout<<comma;
 121     x.render(std::cout);
 122     comma=",";
 123   }
 124   std::cout<<"\n";
 125 //]
 126
 127 //[segmented_structure_8
 128   /*=const char**/ comma="";
 129   for(auto first=c.begin<warrior>(),last=c.end<warrior>();
 130       first!=last;++first){
 131     first->rank.insert(0,"super");
 132     std::cout<<comma;
 133     first->render(std::cout);
 134     comma=",";
 135   }
 136   std::cout<<"\n";
 137
 138   // range-based for loop alternative
 139
 140   /*=const char**/ comma="";
 141   for(auto& x:c.segment<warrior>()){
 142     x.rank.insert(0,"super");
 143 //<-
 144     auto it=x.rank.begin();
 145     x.rank.erase(it,it+5); // undo previos op, 5==len("super");
 146 //->
 147     std::cout<<comma;
 148     x.render(std::cout);
 149     comma=",";
 150   }
 151   std::cout<<"\n";
 152
 153 //]
 154
 155   auto render=[&](){
 156 //[segmented_structure_9
 157   const char* comma="";
 158   for(auto seg:c.segment_traversal()){
 159     for(sprite& s:seg){
 160       std::cout<<comma;
 161       s.render(std::cout);
 162       comma=",";
 163     }
 164   }
 165   std::cout<<"\n";
 166 //]
 167   };
 168   render();
 169
 170 //[segmented_structure_10
 171   c.reserve<goblin>(100); // no reallocation till we exceed 100 goblins
 172   std::cout<<c.capacity<goblin>()<<"\n"; // prints 100
 173 //]
 174
 175 //[segmented_structure_11
 176   c.reserve(1000); // reserve(1000) for each segment
 177   std::cout<<c.capacity<warrior>()<<", "
 178            <<c.capacity<juggernaut>()<<", "
 179            <<c.capacity<goblin>()<<"\n"; // prints 1000, 1000, 1000
 180 //]
 181 }