container/experimental/segmented_remove_test.cpp

//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2025-2026. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/container for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#include <boost/container/experimental/segmented_remove.hpp>
#include <boost/core/lightweight_test.hpp>
#include "segmented_test_helper.hpp"
#include <boost/container/vector.hpp>

using namespace boost::container;

void test_remove_segmented()
{
   test_detail::seg_vector<int> sv;
   int a1[] = {1, 2, 3};
   int a2[] = {2, 4, 2};
   int a3[] = {5, 2};
   sv.add_segment_range(a1, a1 + 3);
   sv.add_segment_range(a2, a2 + 3);
   sv.add_segment_range(a3, a3 + 2);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(sv.begin(), sv.end(), 2);

   int expected[] = {1, 3, 4, 5};
   iter_t it = sv.begin();
   for(int i = 0; i < 4; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST(it == new_end);
}

void test_remove_no_match()
{
   test_detail::seg_vector<int> sv;
   int a1[] = {1, 3, 5};
   sv.add_segment_range(a1, a1 + 3);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(sv.begin(), sv.end(), 2);
   BOOST_TEST(new_end == sv.end());
}

void test_remove_all_match()
{
   test_detail::seg_vector<int> sv;
   sv.add_segment(3, 2);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(sv.begin(), sv.end(), 2);
   BOOST_TEST(new_end == sv.begin());
}

void test_remove_empty()
{
   test_detail::seg_vector<int> sv;
   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(sv.begin(), sv.end(), 0);
   BOOST_TEST(new_end == sv.begin());
}

void test_remove_non_segmented()
{
   boost::container::vector<int> v;
   v.push_back(1); v.push_back(2); v.push_back(3); v.push_back(2); v.push_back(4);

   boost::container::vector<int>::iterator new_end = segmented_remove(v.begin(), v.end(), 2);
   BOOST_TEST_EQ(new_end - v.begin(), 3);
   BOOST_TEST_EQ(v[0], 1);
   BOOST_TEST_EQ(v[1], 3);
   BOOST_TEST_EQ(v[2], 4);
}

void test_remove_sentinel_segmented()
{
   test_detail::seg_vector<int> sv;
   int a1[] = {1, 2, 3};
   int a2[] = {2, 4, 2};
   int a3[] = {5, 2};
   sv.add_segment_range(a1, a1 + 3);
   sv.add_segment_range(a2, a2 + 3);
   sv.add_segment_range(a3, a3 + 2);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(sv.begin(), test_detail::make_sentinel(sv.end()), 2);

   int expected[] = {1, 3, 4, 5};
   iter_t it = sv.begin();
   for(int i = 0; i < 4; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST(it == new_end);
}

void test_remove_sentinel_non_segmented()
{
   boost::container::vector<int> v;
   v.push_back(1); v.push_back(2); v.push_back(3); v.push_back(2); v.push_back(4);

   boost::container::vector<int>::iterator new_end = segmented_remove(v.begin(), test_detail::make_sentinel(v.end()), 2);
   BOOST_TEST_EQ(new_end - v.begin(), 3);
   BOOST_TEST_EQ(v[0], 1);
   BOOST_TEST_EQ(v[1], 3);
   BOOST_TEST_EQ(v[2], 4);
}

void test_remove_seg2()
{
   test_detail::seg2_vector<int> sv2;
   int a1[] = {1, 2, 3};
   int a2[] = {2, 4, 2};
   int a3[] = {5, 2};
   sv2.add_flat_segment_range(a1, a1 + 3);
   sv2.add_flat_segment_range(a2, a2 + 3);
   sv2.add_flat_segment_range(a3, a3 + 2);

   typedef test_detail::seg2_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(sv2.begin(), sv2.end(), 2);

   int expected[] = {1, 3, 4, 5};
   iter_t it = sv2.begin();
   for(int i = 0; i < 4; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST(it == new_end);
}

void test_remove_movable_seg()
{
   typedef test_detail::movable_int mi;
   test_detail::seg_vector<mi> sv;
   int a1[] = {1, 2, 3};
   int a2[] = {2, 4, 2};
   int a3[] = {5, 2};
   sv.add_segment_from_ints(a1, a1 + 3);
   sv.add_segment_from_ints(a2, a2 + 3);
   sv.add_segment_from_ints(a3, a3 + 2);

   typedef test_detail::seg_vector<mi>::iterator iter_t;
   iter_t new_end = segmented_remove(sv.begin(), sv.end(), mi(2));

   int expected[] = {1, 3, 4, 5};
   iter_t it = sv.begin();
   for(int i = 0; i < 4; ++i, ++it)
      BOOST_TEST_EQ(it->value(), expected[i]);
   BOOST_TEST(it == new_end);
}

void test_remove_movable_seg2()
{
   typedef test_detail::movable_int mi;
   test_detail::seg2_vector<mi> sv2;
   int a1[] = {1, 2, 3};
   int a2[] = {2, 4, 2};
   int a3[] = {5, 2};
   sv2.add_flat_segment_from_ints(a1, a1 + 3);
   sv2.add_flat_segment_from_ints(a2, a2 + 3);
   sv2.add_flat_segment_from_ints(a3, a3 + 2);

   typedef test_detail::seg2_vector<mi>::iterator iter_t;
   iter_t new_end = segmented_remove(sv2.begin(), sv2.end(), mi(2));

   int expected[] = {1, 3, 4, 5};
   iter_t it = sv2.begin();
   for(int i = 0; i < 4; ++i, ++it)
      BOOST_TEST_EQ(it->value(), expected[i]);
   BOOST_TEST(it == new_end);
}

void test_remove_single_segment_interior()
{
   test_detail::seg_vector<int> sv;
   int a[] = {100, 1, 2, 3, 2, 5, 200};
   sv.add_segment_range(a, a + 7);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(test_detail::iter_at(sv, 1), test_detail::iter_at(sv, 6), 2);

   BOOST_TEST(new_end == test_detail::iter_at(sv, 4));
   int expected[] = {1, 3, 5};
   iter_t it = test_detail::iter_at(sv, 1);
   for(int i = 0; i < 3; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST_EQ(*test_detail::iter_at(sv, 0), 100);
   BOOST_TEST_EQ(*test_detail::iter_at(sv, 6), 200);
}

void test_remove_single_segment_first_element()
{
   test_detail::seg_vector<int> sv;
   int a[] = {100, 2, 1, 3, 5, 200};
   sv.add_segment_range(a, a + 6);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(test_detail::iter_at(sv, 1), test_detail::iter_at(sv, 5), 2);

   BOOST_TEST(new_end == test_detail::iter_at(sv, 4));
   int expected[] = {1, 3, 5};
   iter_t it = test_detail::iter_at(sv, 1);
   for(int i = 0; i < 3; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST_EQ(*test_detail::iter_at(sv, 0), 100);
   BOOST_TEST_EQ(*test_detail::iter_at(sv, 5), 200);
}

void test_remove_single_segment_last_element()
{
   test_detail::seg_vector<int> sv;
   int a[] = {100, 1, 3, 5, 2, 200};
   sv.add_segment_range(a, a + 6);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(test_detail::iter_at(sv, 1), test_detail::iter_at(sv, 5), 2);

   BOOST_TEST(new_end == test_detail::iter_at(sv, 4));
   int expected[] = {1, 3, 5};
   iter_t it = test_detail::iter_at(sv, 1);
   for(int i = 0; i < 3; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST_EQ(*test_detail::iter_at(sv, 0), 100);
   BOOST_TEST_EQ(*test_detail::iter_at(sv, 5), 200);
}

void test_remove_single_segment_no_match()
{
   test_detail::seg_vector<int> sv;
   int a[] = {100, 1, 3, 5, 7, 200};
   sv.add_segment_range(a, a + 6);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(test_detail::iter_at(sv, 1), test_detail::iter_at(sv, 5), 2);

   BOOST_TEST(new_end == test_detail::iter_at(sv, 5));
   iter_t it = sv.begin();
   for(int i = 0; i < 6; ++i, ++it)
      BOOST_TEST_EQ(*it, a[i]);
}

void test_remove_single_segment_empty_mid()
{
   test_detail::seg_vector<int> sv;
   int a[] = {1, 2, 3, 2, 5, 6};
   sv.add_segment_range(a, a + 6);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t mid = test_detail::iter_at(sv, 3);
   iter_t new_end = segmented_remove(mid, mid, 2);

   BOOST_TEST(new_end == mid);
   iter_t it = sv.begin();
   for(int i = 0; i < 6; ++i, ++it)
      BOOST_TEST_EQ(*it, a[i]);
}

void test_remove_single_segment_sentinel()
{
   test_detail::seg_vector<int> sv;
   int a[] = {100, 1, 2, 3, 2, 5, 200};
   sv.add_segment_range(a, a + 7);

   typedef test_detail::seg_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(test_detail::iter_at(sv, 1),
                                     test_detail::make_sentinel(test_detail::iter_at(sv, 6)), 2);

   BOOST_TEST(new_end == test_detail::iter_at(sv, 4));
   int expected[] = {1, 3, 5};
   iter_t it = test_detail::iter_at(sv, 1);
   for(int i = 0; i < 3; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST_EQ(*test_detail::iter_at(sv, 0), 100);
   BOOST_TEST_EQ(*test_detail::iter_at(sv, 6), 200);
}

void test_remove_single_segment_seg2_outer()
{
   test_detail::seg2_vector<int> sv2;
   test_detail::seg_vector<int> inner;
   int a1[] = {100, 1, 2};
   int a2[] = {3, 2};
   int a3[] = {5, 200};
   inner.add_segment_range(a1, a1 + 3);
   inner.add_segment_range(a2, a2 + 2);
   inner.add_segment_range(a3, a3 + 2);
   sv2.add_segment(inner);

   typedef test_detail::seg2_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(test_detail::iter_at(sv2, 1), test_detail::iter_at(sv2, 6), 2);

   BOOST_TEST(new_end == test_detail::iter_at(sv2, 4));
   int expected[] = {1, 3, 5};
   iter_t it = test_detail::iter_at(sv2, 1);
   for(int i = 0; i < 3; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST_EQ(*test_detail::iter_at(sv2, 0), 100);
   BOOST_TEST_EQ(*test_detail::iter_at(sv2, 6), 200);
}

void test_remove_single_segment_seg2_both()
{
   test_detail::seg2_vector<int> sv2;
   test_detail::seg_vector<int> inner;
   int a[] = {100, 1, 2, 3, 2, 5, 200};
   inner.add_segment_range(a, a + 7);
   sv2.add_segment(inner);

   typedef test_detail::seg2_vector<int>::iterator iter_t;
   iter_t new_end = segmented_remove(test_detail::iter_at(sv2, 1), test_detail::iter_at(sv2, 6), 2);

   BOOST_TEST(new_end == test_detail::iter_at(sv2, 4));
   int expected[] = {1, 3, 5};
   iter_t it = test_detail::iter_at(sv2, 1);
   for(int i = 0; i < 3; ++i, ++it)
      BOOST_TEST_EQ(*it, expected[i]);
   BOOST_TEST_EQ(*test_detail::iter_at(sv2, 0), 100);
   BOOST_TEST_EQ(*test_detail::iter_at(sv2, 6), 200);
}

//////////////////////////////////////////////////////////////////////////////
// Shape matrix.
//
// segmented_remove is in place, so there is only one range and
// for_each_shape_all is the right combinator: the twelve branch specs over
// both segmentation depths, the 'e' ones carrying empty segments.
//
// What can be asserted after the call is the returned new logical end, the
// surviving prefix in front of it, and the guard just past the end of the
// range.  The elements between the new end and the old one are left in a
// valid-but-unspecified state by definition, so nothing is asserted about
// them.  The reference is filtered out of flatten_n_ints over the logical
// range, not flatten_all_ints, which deliberately includes the guard.
//////////////////////////////////////////////////////////////////////////////

const int shape_removed = 2;     // the value handed to segmented_remove
const int shape_filler  = -999;  // guard just past the end of the range

struct remove_shape_check
{
   template<class C>
   void operator()(C& c, std::size_t n, const char* spec) const
   {
      typedef typename C::iterator iter_t;

      const boost::container::vector<int> in = test_detail::flatten_n_ints(c, n);
      boost::container::vector<int> ref;
      for(std::size_t i = 0; i != n; ++i)
         if(in[i] != shape_removed)
            ref.push_back(in[i]);

      const iter_t new_end = segmented_remove(c.begin(), test_detail::iter_at(c, n), shape_removed);

      BOOST_TEST(new_end == test_detail::iter_at(c, ref.size()));
      BOOST_TEST(test_detail::filler_intact(c, n, shape_filler));

      const boost::container::vector<int> got = test_detail::flatten_n_ints(c, ref.size());
      BOOST_TEST_EQ(got.size(), ref.size());
      for(std::size_t i = 0; i != ref.size(); ++i)
         BOOST_TEST_EQ(got[i], ref[i]);

      BOOST_TEST(spec != 0);
   }
};

void test_remove_shape_matrix()
{
   // Interleaved removals, a leading and a trailing removal, nothing removed
   // and everything removed, so the empty and the full answer are both in.
   static const int mixed[]  = {1, 2, 3, 2, 4, 2, 5, 6, 2, 7};
   static const int edges[]  = {2, 1, 3, 4, 5, 2};
   static const int none[]   = {1, 3, 5, 7, 9, 11};
   static const int all_rm[] = {2, 2, 2, 2, 2, 2};
   static const int* const sets[] = {mixed, edges, none, all_rm};
   static const std::size_t set_len[] = {10u, 6u, 6u, 6u};
   static const std::size_t sizes[] = {0u, 1u, 2u, 3u, 5u, 6u, 10u};

   for(std::size_t s = 0; s != sizeof(sets)/sizeof(sets[0]); ++s) {
      for(std::size_t i = 0; i != sizeof(sizes)/sizeof(sizes[0]); ++i) {
         const std::size_t n = sizes[i];
         if(n > set_len[s])
            continue;
         test_detail::for_each_shape_all<int>
            (sets[s], n, shape_filler, remove_shape_check());
      }
   }
}

//////////////////////////////////////////////////////////////////////////////
// Comparison count.
//
// [alg.remove] mandates "Exactly last - first applications of the
// corresponding predicate or comparison", so an element compared twice at a
// segment boundary is a conformance failure.  segmented_remove is built from
// segmented_find plus segmented_remove_copy, and the count is what catches
// the join between them re-testing the element find stopped on.
//////////////////////////////////////////////////////////////////////////////

struct remove_comparison_check
{
   template<class C>
   void operator()(C& c, std::size_t n, const char* spec) const
   {
      test_detail::counted_int_ops().reset();
      segmented_remove(c.begin(), test_detail::iter_at(c, n),
                       test_detail::counted_int(shape_removed));
      const std::size_t applied = test_detail::counted_int_ops().cmp;

      BOOST_TEST_EQ(applied, n);
      BOOST_TEST(spec != 0);
   }
};

void test_remove_comparison_count()
{
   static const int mixed[]  = {1, 2, 3, 2, 4, 2, 5, 6, 2, 7};
   static const int edges[]  = {2, 1, 3, 4, 5, 2};
   static const int none[]   = {1, 3, 5, 7, 9, 11};
   static const int all_rm[] = {2, 2, 2, 2, 2, 2};
   static const int* const sets[] = {mixed, edges, none, all_rm};
   static const std::size_t set_len[] = {10u, 6u, 6u, 6u};
   static const std::size_t sizes[] = {0u, 1u, 2u, 3u, 5u, 6u, 10u};

   for(std::size_t s = 0; s != sizeof(sets)/sizeof(sets[0]); ++s) {
      for(std::size_t i = 0; i != sizeof(sizes)/sizeof(sizes[0]); ++i) {
         const std::size_t n = sizes[i];
         if(n > set_len[s])
            continue;
         test_detail::for_each_shape_all<test_detail::counted_int>
            (sets[s], n, shape_filler, remove_comparison_check());
      }
   }
}

int main()
{
   test_remove_segmented();
   test_remove_no_match();
   test_remove_all_match();
   test_remove_single_segment_interior();
   test_remove_single_segment_first_element();
   test_remove_single_segment_last_element();
   test_remove_single_segment_no_match();
   test_remove_single_segment_empty_mid();
   test_remove_single_segment_sentinel();
   test_remove_single_segment_seg2_outer();
   test_remove_single_segment_seg2_both();
   test_remove_empty();
   test_remove_non_segmented();
   test_remove_sentinel_segmented();
   test_remove_sentinel_non_segmented();
   test_remove_seg2();
   test_remove_movable_seg();
   test_remove_movable_seg2();
   test_remove_shape_matrix();
   test_remove_comparison_count();
   return boost::report_errors();
}