libstdc++-v3/testsuite/25_algorithms/stable_partition/1.cc

   1 // Copyright (C) 2001-2025 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // 25.2.12 [lib.alg.partitions] Partitions.
  19
  20 // std::stable_partition is not freestanding.
  21 // { dg-require-effective-target hosted }
  22
  23 #include <algorithm>
  24 #include <functional>
  25 #include <testsuite_new_operators.h>
  26 #include <testsuite_hooks.h>
  27 #include <testsuite_iterators.h>
  28
  29 const int A[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17};
  30 const int B[] = {2, 4, 6, 8, 10, 12, 14, 16, 1, 3, 5, 7, 9, 11, 13, 15, 17};
  31 const int N = sizeof(A) / sizeof(int);
  32
  33 // Index of the middle element that should be returned by the algo.
  34 const int M = 8;
  35
  36 struct Pred
  37 {
  38     bool
  39     operator()(const int& x) const
  40     { return (x % 2) == 0; }
  41 };
  42
  43 // 25.2.12 stable_partition()
  44 void
  45 test01()
  46 {
  47   using std::stable_partition;
  48   using __gnu_test::test_container;
  49   using __gnu_test::forward_iterator_wrapper;
  50
  51   int s1[N];
  52   std::copy(A, A + N, s1);
  53
  54   test_container<int, forward_iterator_wrapper> c(s1, s1+N);
  55   forward_iterator_wrapper<int> expected = c.begin();
  56   std::advance(expected, M);
  57   VERIFY( stable_partition(c.begin(), c.end(), Pred()) == expected);
  58   VERIFY( std::equal(s1, s1 + N, B) );
  59 }
  60
  61 int
  62 main()
  63 {
  64   test01();
  65
  66   // stable_partition rely on an internal buffer if possible. Try to limit the
  67   // size of this buffer to see if algo is robust.
  68
  69   // Limit to half of the necessary buffer.
  70   __gnu_test::set_new_limit(sizeof(A) / 2);
  71   test01();
  72
  73   // Limit to just 1 element.
  74   __gnu_test::set_new_limit(sizeof(int));
  75   test01();
  76
  77   // Limit to 0
  78   __gnu_test::set_new_limit(0);
  79   test01();
  80
  81   return 0;
  82 }