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