variadic-argument-picker-test.cpp

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/*
  VariadicArgumentPicker(Test)  -  access individual arguments from a variadic template
 
   Copyright (C)
     2008,            Hermann Vosseler <Ichthyostega@web.de>
 
 **Lumiera** 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. See the file COPYING for further details.
 
* *****************************************************************/
 
 
#include "lib/test/run.hpp"
#include "lib/meta/variadic-helper.hpp"
#include "lib/format-string.hpp"
#include "lib/format-cout.hpp"
#include "lib/format-util.hpp"
 
#include <utility>
 
using util::_Fmt;
using util::join;
using util::toString;
using std::forward;
using std::string;
 
 
namespace lib  {
namespace meta {
namespace test {
  
  
  namespace { // test data
    
    template<int n>
    struct N
      {
        uint i_;
        static int instanceCnt;
        
        N (uint x = rani(1 + abs(n)))
          : i_{x}
          {
            ++instanceCnt;
          }
       ~N()
          {
            --instanceCnt;
          }
        N (N const& r)
          : i_{r.i_}
          {
            ++instanceCnt;
          }
        N (N&& rr)
          {
            std::swap (i_, rr.i_);
            ++instanceCnt;
          }
        
        // instanceCnt remains same...
        N& operator= (N const&) = default;
        N& operator= (N&&)      = default;
        
        operator string()  const
          {
            static _Fmt format{"%s──%s─"};
            return format % typeStr(*this) % i_;
          }
        friend bool operator== (N const& l, N const& r) { return l.i_ == r.i_; }
        friend bool operator!= (N const& l, N const& r) { return l.i_ != r.i_; }
      };
    
    template<int n>
    int N<n>::instanceCnt = 0;
    
    
    template<class...ARGS>
    string
    fun (ARGS&& ...args)
    {
      static _Fmt format{"%2d╎%s┤"};
      return format % sizeof...(ARGS) % join({toString(args)...}, "┼");
    }
  } // (End) test data
  
  
  
  
  
  
  /****************************************************************************/
  class VariadicArgumentPicker_test : public Test
    {
      virtual void
      run (Arg)
        {
          seedRand();
          verify_fixture();
          check_pickArg ();
          check_pickInit();
          check_reorderedArguments();
          
          CHECK (0 == N<0>::instanceCnt);
          CHECK (0 == N<1>::instanceCnt);
          CHECK (0 == N<2>::instanceCnt);
          CHECK (0 == N<3>::instanceCnt);
        }
      
      
      void
      verify_fixture ()
        {
          CHECK (0 == N<0>::instanceCnt);
          CHECK (0 == N<1>::instanceCnt);
          CHECK (0 == N<2>::instanceCnt);
          CHECK (0 == N<3>::instanceCnt);
          {
            N<1> n1;
            N<2> n2;
            N<3> n3;
            N<3> nn{n3};
            cout << fun (n1,n2,n3,nn) << endl;
            
            CHECK (0 == N<0>::instanceCnt);
            CHECK (1 == N<1>::instanceCnt);
            CHECK (1 == N<2>::instanceCnt);
            CHECK (2 == N<3>::instanceCnt);
 
          }
          CHECK (0 == N<0>::instanceCnt);
          CHECK (0 == N<1>::instanceCnt);
          CHECK (0 == N<2>::instanceCnt);
          CHECK (0 == N<3>::instanceCnt);
        }
      
      
      void
      check_pickArg ()
        {
          N<1> n1;
          N<2> n2;
          N<3> n3;
          
          CHECK (n1 == pickArg<0> (n1,n2,n3));
          CHECK (n2 == pickArg<1> (n1,n2,n3));
          CHECK (n3 == pickArg<2> (n1,n2,n3));
 
          // does not compile...
//        pickArg<3> (n1,n2,n3);
          
          N<0> n0{42};
          CHECK (n0 != pickArg<0> (N<0>{23}));
          CHECK (n0 == pickArg<0> (N<0>{n0}));
        }
      
      
      void
      check_pickInit ()
        {
          N<1> n1;
          N<2> n2;
          using N0 = N<0>;
          
          CHECK (1 == (pickInit<0,int> (1,2) ));
          CHECK (2 == (pickInit<1,int> (1,2) ));
          CHECK (0 == (pickInit<2,int> (1,2) ));
          
          CHECK (n1 == (pickInit<0,N0> (n1,n2) ));
          CHECK (n2 == (pickInit<1,N0> (n1,n2) ));
          
          CHECK ("N<0>" == typeStr(pickInit<3,N0> (n1,n2)));
          CHECK ("N<0>" == typeStr(pickInit<3,N0> (1,"2")));
          CHECK ("N<0>" == typeStr(pickInit<3,N0> ()));
        }
      
      
      
      template<class...ARGS, size_t...idx>
      static auto
      call_with_reversed_arguments (IndexSeq<idx...>, ARGS&& ...args)
        {
          return fun (pickArg<idx> (forward<ARGS>(args)...) ...);
        }
      
      void
      check_reorderedArguments ()
        {
          N<0> n0;
          N<1> n1;
          N<2> n2;
          N<3> n3;
          
          cout << fun (n0,n1,n2,n3) << endl;
          
          using Backwards = BuildIndexSeq<4>::Descending;    // 3,2,1,0
          using Back2     = BuildIndexSeq<2>::Descending;    // 1,0
          using After2    = BuildIndexSeq<4>::After<2>;      // 2,3
          
          cout << call_with_reversed_arguments (Backwards(), n0,n1,n2,n3)  <<endl;
          cout << call_with_reversed_arguments (Back2()    , n0,n1,n2,n3)  <<endl;
          cout << call_with_reversed_arguments (After2()   , n0,n1,n2,n3)  <<endl;
        }
    };
  
  
  LAUNCHER (VariadicArgumentPicker_test, "unit common");
  
  
  
}}} // namespace lib::meta::test