llvm-project/libcxx/test/std/ranges/range.access/data.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++03, c++11, c++14, c++17
// UNSUPPORTED: libcpp-no-concepts
// UNSUPPORTED: libcpp-has-no-incomplete-ranges

// std::ranges::data

#include <ranges>

#include <cassert>
#include <type_traits>
#include "test_macros.h"
#include "test_iterators.h"

using RangeDataT = decltype(std::ranges::data);

static int globalBuff[2];

struct Incomplete;

static_assert(!std::is_invocable_v<RangeDataT, Incomplete[]>);
static_assert(!std::is_invocable_v<RangeDataT, Incomplete(&&)[2]>);
static_assert(!std::is_invocable_v<RangeDataT, Incomplete(&&)[2][2]>);
static_assert(!std::is_invocable_v<RangeDataT, int [1]>);
static_assert(!std::is_invocable_v<RangeDataT, int (&&)[1]>);
static_assert( std::is_invocable_v<RangeDataT, int (&)[1]>);

struct DataMember {
  int x;
  constexpr const int *data() const { return &x; }
};
static_assert( std::is_invocable_v<RangeDataT, DataMember &>);
static_assert(!std::is_invocable_v<RangeDataT, DataMember &&>);
static_assert( std::is_invocable_v<RangeDataT, DataMember const&>);
static_assert(!std::is_invocable_v<RangeDataT, DataMember const&&>);

constexpr bool testReturnTypes() {
  {
    int *x[2];
    ASSERT_SAME_TYPE(decltype(std::ranges::data(x)), int**);
  }
  {
    int x[2][2];
    ASSERT_SAME_TYPE(decltype(std::ranges::data(x)), int(*)[2]);
  }
  {
    struct D {
      char*& data();
      short*& data() const;
    };
    ASSERT_SAME_TYPE(decltype(std::ranges::data(std::declval<D&>())), char*);
    static_assert(!std::is_invocable_v<RangeDataT, D&&>);
    ASSERT_SAME_TYPE(decltype(std::ranges::data(std::declval<const D&>())), short*);
    static_assert(!std::is_invocable_v<RangeDataT, const D&&>);
  }
  {
    struct NC {
      char *begin() const;
      char *end() const;
      int *data();
    };
    static_assert(!std::ranges::contiguous_range<NC>);
    static_assert( std::ranges::contiguous_range<const NC>);
    ASSERT_SAME_TYPE(decltype(std::ranges::data(std::declval<NC&>())), int*);
    static_assert(!std::is_invocable_v<RangeDataT, NC&&>);
    ASSERT_SAME_TYPE(decltype(std::ranges::data(std::declval<const NC&>())), char*);
    static_assert(!std::is_invocable_v<RangeDataT, const NC&&>);
  }
  return true;
}

struct VoidDataMember {
  void *data() const;
};
static_assert(!std::is_invocable_v<RangeDataT, VoidDataMember const&>);

struct Empty { };
struct EmptyDataMember {
  Empty data() const;
};
static_assert(!std::is_invocable_v<RangeDataT, EmptyDataMember const&>);

struct PtrConvertibleDataMember {
  struct Ptr {
    operator int*() const;
  };
  Ptr data() const;
};
static_assert(!std::is_invocable_v<RangeDataT, PtrConvertibleDataMember const&>);

struct NonConstDataMember {
  int x;
  constexpr int *data() { return &x; }
};

struct EnabledBorrowingDataMember {
  constexpr int *data() { return &globalBuff[0]; }
};
template<>
inline constexpr bool std::ranges::enable_borrowed_range<EnabledBorrowingDataMember> = true;

struct DataMemberAndBegin {
  int x;
  constexpr const int *data() const { return &x; }
  const int *begin() const;
};

constexpr bool testDataMember() {
  DataMember a;
  assert(std::ranges::data(a) == &a.x);

  NonConstDataMember b;
  assert(std::ranges::data(b) == &b.x);

  EnabledBorrowingDataMember c;
  assert(std::ranges::data(std::move(c)) == &globalBuff[0]);

  DataMemberAndBegin d;
  assert(std::ranges::data(d) == &d.x);

  return true;
}

using ContiguousIter = contiguous_iterator<const int*>;

struct BeginMemberContiguousIterator {
  int buff[8];

  constexpr ContiguousIter begin() const { return ContiguousIter(buff); }
};
static_assert( std::is_invocable_v<RangeDataT, BeginMemberContiguousIterator &>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberContiguousIterator &&>);
static_assert( std::is_invocable_v<RangeDataT, BeginMemberContiguousIterator const&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberContiguousIterator const&&>);

struct BeginMemberRandomAccess {
  int buff[8];

  random_access_iterator<const int*> begin() const;
};
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberRandomAccess&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberRandomAccess&&>);
static_assert(!std::is_invocable_v<RangeDataT, const BeginMemberRandomAccess&>);
static_assert(!std::is_invocable_v<RangeDataT, const BeginMemberRandomAccess&&>);

struct BeginFriendContiguousIterator {
  int buff[8];

  friend constexpr ContiguousIter begin(const BeginFriendContiguousIterator &iter) {
    return ContiguousIter(iter.buff);
  }
};
static_assert( std::is_invocable_v<RangeDataT, BeginMemberContiguousIterator &>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberContiguousIterator &&>);
static_assert( std::is_invocable_v<RangeDataT, BeginMemberContiguousIterator const&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberContiguousIterator const&&>);

struct BeginFriendRandomAccess {
  friend random_access_iterator<const int*> begin(const BeginFriendRandomAccess iter);
};
static_assert(!std::is_invocable_v<RangeDataT, BeginFriendRandomAccess&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginFriendRandomAccess&&>);
static_assert(!std::is_invocable_v<RangeDataT, const BeginFriendRandomAccess&>);
static_assert(!std::is_invocable_v<RangeDataT, const BeginFriendRandomAccess&&>);

struct BeginMemberRvalue {
  int buff[8];

  ContiguousIter begin() &&;
};
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberRvalue&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberRvalue&&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberRvalue const&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberRvalue const&&>);

struct BeginMemberBorrowingEnabled {
  constexpr contiguous_iterator<int*> begin() { return contiguous_iterator<int*>{&globalBuff[1]}; }
};
template<>
inline constexpr bool std::ranges::enable_borrowed_range<BeginMemberBorrowingEnabled> = true;
static_assert( std::is_invocable_v<RangeDataT, BeginMemberBorrowingEnabled &>);
static_assert( std::is_invocable_v<RangeDataT, BeginMemberBorrowingEnabled &&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberBorrowingEnabled const&>);
static_assert(!std::is_invocable_v<RangeDataT, BeginMemberBorrowingEnabled const&&>);

constexpr bool testViaRangesBegin() {
  int arr[2];
  assert(std::ranges::data(arr) == arr + 0);

  BeginMemberContiguousIterator a;
  assert(std::ranges::data(a) == a.buff);

  const BeginFriendContiguousIterator b {};
  assert(std::ranges::data(b) == b.buff);

  BeginMemberBorrowingEnabled c;
  assert(std::ranges::data(std::move(c)) == &globalBuff[1]);

  return true;
}

// Test ADL-proofing.
struct Incomplete;
template<class T> struct Holder { T t; };
static_assert(!std::is_invocable_v<RangeDataT, Holder<Incomplete>*>);

struct RandomButNotContiguous {
  random_access_iterator<int*> begin() const;
  random_access_iterator<int*> end() const;
};
static_assert(!std::is_invocable_v<RangeDataT, RandomButNotContiguous>);

int main(int, char**) {
  static_assert(testReturnTypes());

  testDataMember();
  static_assert(testDataMember());

  testViaRangesBegin();
  static_assert(testViaRangesBegin());

  return 0;
}