third_party/boost/unordered/test/unordered/incomplete_test.cpp

// Copyright 2009 Daniel James.
// 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)

// clang-format off
#include "../helpers/prefix.hpp"
#include <boost/unordered_map.hpp>
#include <boost/unordered_set.hpp>
#include "../helpers/postfix.hpp"
// clang-format on

#include <utility>

namespace x {
  struct D
  {
    boost::unordered_map<D, D> x;
  };
}

namespace incomplete_test {
  // Declare, but don't define some types.

  struct value;
  struct hash;
  struct equals;
  template <class T> struct allocator;

  // Declare some instances

  typedef boost::unordered_map<value, value, hash, equals,
    allocator<std::pair<value const, value> > >
    map;
  typedef boost::unordered_multimap<value, value, hash, equals,
    allocator<std::pair<value const, value> > >
    multimap;
  typedef boost::unordered_set<value, hash, equals, allocator<value> > set;
  typedef boost::unordered_multiset<value, hash, equals, allocator<value> >
    multiset;

  // Now define the types which are stored as members, as they are needed for
  // declaring struct members.

  struct hash
  {
    template <typename T> std::size_t operator()(T const&) const { return 0; }
  };

  struct equals
  {
    template <typename T> bool operator()(T const&, T const&) const
    {
      return true;
    }
  };

  // This is a dubious way to implement an allocator, but good enough
  // for this test.
  template <typename T> struct allocator : std::allocator<T>
  {
    allocator() {}

    template <typename T2>
    allocator(const allocator<T2>& other) : std::allocator<T>(other)
    {
    }

    template <typename T2>
    allocator(const std::allocator<T2>& other) : std::allocator<T>(other)
    {
    }
  };

  // Declare some members of a structs.
  //
  // Incomplete hash, equals and allocator aren't here supported at the
  // moment.

  struct struct1
  {
    boost::unordered_map<struct1, struct1, hash, equals,
      allocator<std::pair<struct1 const, struct1> > >
      x;
  };
  struct struct2
  {
    boost::unordered_multimap<struct2, struct2, hash, equals,
      allocator<std::pair<struct2 const, struct2> > >
      x;
  };
  struct struct3
  {
    boost::unordered_set<struct3, hash, equals, allocator<struct3> > x;
  };
  struct struct4
  {
    boost::unordered_multiset<struct4, hash, equals, allocator<struct4> > x;
  };

  // Now define the value type.

  struct value
  {
  };

  // Create some instances.

  incomplete_test::map m1;
  incomplete_test::multimap m2;
  incomplete_test::set s1;
  incomplete_test::multiset s2;

  incomplete_test::struct1 c1;
  incomplete_test::struct2 c2;
  incomplete_test::struct3 c3;
  incomplete_test::struct4 c4;

  // Now declare, but don't define, the operators required for comparing
  // elements.

  std::size_t hash_value(value const&);
  bool operator==(value const&, value const&);

  std::size_t hash_value(struct1 const&);
  std::size_t hash_value(struct2 const&);
  std::size_t hash_value(struct3 const&);
  std::size_t hash_value(struct4 const&);

  bool operator==(struct1 const&, struct1 const&);
  bool operator==(struct2 const&, struct2 const&);
  bool operator==(struct3 const&, struct3 const&);
  bool operator==(struct4 const&, struct4 const&);

  // And finally use these

  void use_types()
  {
    incomplete_test::value x;
    m1[x] = x;
    m2.insert(std::make_pair(x, x));
    s1.insert(x);
    s2.insert(x);

    c1.x.insert(std::make_pair(c1, c1));
    c2.x.insert(std::make_pair(c2, c2));
    c3.x.insert(c3);
    c4.x.insert(c4);
  }

  // And finally define the operators required for comparing elements.

  std::size_t hash_value(value const&) { return 0; }
  bool operator==(value const&, value const&) { return true; }

  std::size_t hash_value(struct1 const&) { return 0; }
  std::size_t hash_value(struct2 const&) { return 0; }
  std::size_t hash_value(struct3 const&) { return 0; }
  std::size_t hash_value(struct4 const&) { return 0; }

  bool operator==(struct1 const&, struct1 const&) { return true; }
  bool operator==(struct2 const&, struct2 const&) { return true; }
  bool operator==(struct3 const&, struct3 const&) { return true; }
  bool operator==(struct4 const&, struct4 const&) { return true; }
}

int main()
{
  // This could just be a compile test, but I like to be able to run these
  // things. It's probably irrational, but I find it reassuring.

  incomplete_test::use_types();
}