libcxx/test/support/test_constexpr_container.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef SUPPORT_TEST_CONSTEXPR_CONTAINER_H
  10 #define SUPPORT_TEST_CONSTEXPR_CONTAINER_H
  11
  12 // A dummy container with enough constexpr support to test the standard
  13 // insert iterators, such as `back_insert_iterator`.
  14
  15 #include <algorithm>
  16 #include <cassert>
  17 #include <cstddef>
  18 #include <utility>
  19
  20 #include "test_macros.h"
  21
  22 #if TEST_STD_VER >= 14
  23
  24 template<class T, int N>
  25 class ConstexprFixedCapacityDeque {
  26     T data_[N];
  27     int size_ = 0;
  28 public:
  29     using value_type = T;
  30     using iterator = T *;
  31     using const_iterator = T const *;
  32
  33     constexpr ConstexprFixedCapacityDeque() = default;
  34     constexpr iterator begin() { return data_; }
  35     constexpr iterator end() { return data_ + size_; }
  36     constexpr const_iterator begin() const { return data_; }
  37     constexpr const_iterator end() const { return data_ + size_; }
  38     constexpr std::size_t size() const { return size_; }
  39     constexpr const T& front() const { assert(size_ >= 1); return data_[0]; }
  40     constexpr const T& back() const { assert(size_ >= 1); return data_[size_-1]; }
  41
  42     constexpr iterator insert(const_iterator pos, T t) {
  43         int i = static_cast<int>(pos - data_);
  44         if (i != size_) {
  45             std::move_backward(data_ + i, data_ + size_, data_ + size_ + 1);
  46         }
  47         data_[i] = std::move(t);
  48         size_ += 1;
  49         return data_ + i;
  50     }
  51
  52     constexpr void push_back(T t) { insert(end(), std::move(t)); }
  53     constexpr void push_front(T t) { insert(begin(), std::move(t)); }
  54 };
  55
  56 #endif // TEST_STD_VER >= 14
  57
  58 #endif // SUPPORT_TEST_CONSTEXPR_CONTAINER_H