unordered/test/helpers/invariants.hpp

// Copyright 2006-2009 Daniel James.
// Copyright 2022 Christian Mazakas.
// 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)

// This header contains metafunctions/functions to get the equivalent
// associative container for an unordered container, and compare the contents.

#if !defined(BOOST_UNORDERED_TEST_HELPERS_INVARIANT_HEADER)
#define BOOST_UNORDERED_TEST_HELPERS_INVARIANT_HEADER

#include "./helpers.hpp"
#include "./metafunctions.hpp"
#include <cmath>
#include <set>

#if defined(BOOST_MSVC)
#pragma warning(push)
#pragma warning(disable : 4127) // conditional expression is constant
#pragma warning(disable : 4267) // conversion from 'size_t' to 'unsigned int',
                                // possible loss of data
#endif

namespace test {
  template <class X> void check_equivalent_keys(X const& x1)
  {
    typename X::key_equal eq = x1.key_eq();
    typedef typename X::key_type key_type;
    std::set<key_type, std::less<key_type> > found_;

    typename X::const_iterator it = x1.begin(), end = x1.end();
    typename X::size_type size = 0;
    while (it != end) {
      // First test that the current key has not occurred before, required
      // to test either that keys are unique or that equivalent keys are
      // adjacent. (6.3.1/6)
      key_type key = get_key<X>(*it);
      if (!found_.insert(key).second)
        BOOST_ERROR("Elements with equivalent keys aren't adjacent.");

      // Iterate over equivalent keys, counting them.
      unsigned int count = 0;
      do {
        ++it;
        ++count;
        ++size;
      } while (it != end && eq(get_key<X>(*it), key));

      // If the container has unique keys, test that there's only one.
      // Since the previous test makes sure that all equivalent keys are
      // adjacent, this is all the equivalent keys - so the test is
      // sufficient. (6.3.1/6 again).
      if (test::has_unique_keys<X>::value && count != 1)
        BOOST_ERROR("Non-unique key.");

#if !defined(BOOST_UNORDERED_FOA_WEAK_GUARANTEE_SWAP_EXCEPTIONS_TESTS)
      // we conditionally compile this check because our FOA implementation only
      // exhibits the weak guarantee when swapping throws
      //
      // in this case, the hasher may be changed before the predicate and the
      // arrays are swapped in which case, we can can find an element by
      // iteration but unfortunately, it's in the wrong slot according to the
      // new hash function so count(key) can wind up returning nothing when
      // there really is something
      if (x1.count(key) != count) {
        BOOST_ERROR("Incorrect output of count.");
        std::cerr << x1.count(key) << "," << count << "\n";
      }
#endif

#ifndef BOOST_UNORDERED_FOA_TESTS
      // Check that the keys are in the correct bucket and are
      // adjacent in the bucket.
      typename X::size_type bucket = x1.bucket(key);
      typename X::const_local_iterator lit = x1.begin(bucket),
                                       lend = x1.end(bucket);

      unsigned int count_checked = 0;
      for (; lit != lend && !eq(get_key<X>(*lit), key); ++lit) {
        ++count_checked;
      }

      if (lit == lend) {
        BOOST_ERROR("Unable to find element with a local_iterator");
        std::cerr << "Checked: " << count_checked << " elements" << std::endl;
      } else {
        unsigned int count2 = 0;
        for (; lit != lend && eq(get_key<X>(*lit), key); ++lit)
          ++count2;
        if (count != count2)
          BOOST_ERROR("Element count doesn't match local_iterator.");
        for (; lit != lend; ++lit) {
          if (eq(get_key<X>(*lit), key)) {
            BOOST_ERROR("Non-adjacent element with equivalent key "
                        "in bucket.");
            break;
          }
        }
      }
#endif
    };

    // Check that size matches up.

    if (x1.size() != size) {
      BOOST_ERROR("x1.size() doesn't match actual size.");
      std::cout << x1.size() << "/" << size << std::endl;
    }

    // Check the load factor.

    float load_factor = size == 0 ? 0
                                  : static_cast<float>(size) /
                                      static_cast<float>(x1.bucket_count());
    using namespace std;
    if (fabs(x1.load_factor() - load_factor) > x1.load_factor() / 64)
      BOOST_ERROR("x1.load_factor() doesn't match actual load_factor.");

#ifndef BOOST_UNORDERED_FOA_TESTS
    // Check that size in the buckets matches up.

    typename X::size_type bucket_size = 0;

    for (typename X::size_type i = 0; i < x1.bucket_count(); ++i) {
      for (typename X::const_local_iterator begin2 = x1.begin(i),
                                            end2 = x1.end(i);
           begin2 != end2; ++begin2) {
        ++bucket_size;
      }
    }

    if (x1.size() != bucket_size) {
      BOOST_ERROR("x1.size() doesn't match bucket size.");
      std::cout << x1.size() << "/" << bucket_size << std::endl;
    }
#endif
  }
}

#if defined(BOOST_MSVC)
#pragma warning(pop)
#endif

#endif