util-floordiv-test.cpp

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/*
  UtilFloordiv(Test)  -  verify integer rounding function

  Copyright (C)         Lumiera.org
    2011,               Hermann Vosseler <Ichthyostega@web.de>

  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.

* *****************************************************/

#include "lib/test/run.hpp"
#include "lib/util-quant.hpp"
#include "lib/util.hpp"

#include "lib/format-cout.hpp"
#include "lib/format-string.hpp"

#include <cmath>
#include <time.h>
#include <vector>

using ::Test;
using std::rand;
using util::isnil;
using util::_Fmt;


namespace util {
namespace test {
  
  
  
  namespace{ // Test data and operations
    
    const uint NUM_ELMS_PERFORMANCE_TEST = 50000000;
    const uint NUMBER_LIMIT              =  1 << 30;
    
    typedef std::vector<int> VecI;
    
    VecI
    buildTestNumberz (uint cnt)
      {
        VecI data;
        for (uint i=0; i<cnt; ++i)
          {
            int someNumber (rand() % (2*NUMBER_LIMIT) -NUMBER_LIMIT);
            if (!someNumber) someNumber -=(1 +rand() % NUMBER_LIMIT);
            
            data.push_back (someNumber);
          }
        return data;
      }
    
    
    inline long
    integerDiv (long num, long den)
      {
        return num / den;
      }
    
    
    inline long
    floordiv_alternate (long num, long den)
      {
        ldiv_t res = ldiv(num,den);
        return (0 >= res.quot && res.rem)? res.quot-1
                                         : res.quot;
      }
    
  } // (End) test data and operations
  
  
  
  /******************************************************************/
  class UtilFloordiv_test : public Test
    {
      
      virtual void
      run (Arg arg)
        {
          verifyBehaviour ();
          
          verifyIntegerTypes<int>();
          verifyIntegerTypes<long>();
          verifyIntegerTypes<short>();
          verifyIntegerTypes<int64_t>();
          verifyIntegerTypes<long long int>();
          
          if (!isnil (arg))
            runPerformanceTest();
        }
      
      
      void
      verifyBehaviour ()
        {
          CHECK ( 3 == floordiv ( 12,4));
          CHECK ( 2 == floordiv ( 11,4));
          CHECK ( 2 == floordiv ( 10,4));
          CHECK ( 2 == floordiv (  9,4));
          CHECK ( 2 == floordiv (  8,4));
          CHECK ( 1 == floordiv (  7,4));
          CHECK ( 1 == floordiv (  6,4));
          CHECK ( 1 == floordiv (  5,4));
          CHECK ( 1 == floordiv (  4,4));
          CHECK ( 0 == floordiv (  3,4));
          CHECK ( 0 == floordiv (  2,4));
          CHECK ( 0 == floordiv (  1,4));
          CHECK ( 0 == floordiv (  0,4));
          CHECK (-1 == floordiv (- 1,4));
          CHECK (-1 == floordiv (- 2,4));
          CHECK (-1 == floordiv (- 3,4));
          CHECK (-1 == floordiv (- 4,4));
          CHECK (-2 == floordiv (- 5,4));
          CHECK (-2 == floordiv (- 6,4));
          CHECK (-2 == floordiv (- 7,4));
          CHECK (-2 == floordiv (- 8,4));
          CHECK (-3 == floordiv (- 9,4));
          CHECK (-3 == floordiv (-10,4));
          CHECK (-3 == floordiv (-11,4));
          CHECK (-3 == floordiv (-12,4));
        }
      
      
      template<typename I>
      void
      verifyIntegerTypes ()
        {
          I n,d,expectedRes;
          
          for (int i=-12; i <= 12; ++i)
            {
              n = i;
              d = 4;
              expectedRes = floordiv (i,4);
              CHECK (floordiv(n,d) == expectedRes);
            }
        }
      
      
      
      void
      runPerformanceTest ()
        {
          VecI testdata = buildTestNumberz (2*NUM_ELMS_PERFORMANCE_TEST);
          typedef VecI::const_iterator I;
          
          clock_t start(0), stop(0);
          _Fmt resultDisplay{"timings(%s)%|30T.|%5.3fsec\n"};
          
#define   START_TIMINGS start=clock();          
#define   DISPLAY_TIMINGS(ID) \
          stop = clock();      \
          cout << resultDisplay % STRINGIFY (ID) % (double(stop-start)/CLOCKS_PER_SEC) ;
          
          START_TIMINGS
          for (I ii =testdata.begin(); ii!=testdata.end(); )
            {
              int num = *ii;
              ++ii;
              int den = *ii;
              ++ii;
              CHECK (floor(double(num)/den) == floordiv(num,den));
            }
          DISPLAY_TIMINGS (Verification)
          
          START_TIMINGS
          for (I ii =testdata.begin(); ii!=testdata.end(); )
            {
              integerDiv (*ii++, *ii++);
            }
          DISPLAY_TIMINGS (Integer_div)
          
          START_TIMINGS
          for (I ii =testdata.begin(); ii!=testdata.end(); )
            {
              floor (double(*ii++) / *ii++);
            }
          DISPLAY_TIMINGS (double_floor)
          
          START_TIMINGS
          for (I ii =testdata.begin(); ii!=testdata.end(); )
            {
              floordiv (*ii++, *ii++);
            }
          DISPLAY_TIMINGS (floordiv_int)
          
          START_TIMINGS
          for (I ii =testdata.begin(); ii!=testdata.end(); )
            {
              floordiv (long(*ii++), long(*ii++));
            }
          DISPLAY_TIMINGS (floordiv_long)
          
          START_TIMINGS
          for (I ii =testdata.begin(); ii!=testdata.end(); )
            {
              floordiv (int64_t(*ii++), int64_t(*ii++));
            }
          DISPLAY_TIMINGS (floordiv_int64_t)
          
          START_TIMINGS
          for (I ii =testdata.begin(); ii!=testdata.end(); )
            {
              floordiv_alternate (*ii++, *ii++);
            }
          DISPLAY_TIMINGS (floordiv_long_alt)
        }
    };
  
  
  
  
  LAUNCHER (UtilFloordiv_test, "unit common");
  
  
}} // namespace util::test