blob: d6a6c37334602d21111a2fe60f1204d8f90f5e41 [file] [log] [blame]
* Copyright 2016 The WebRTC Project Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
#include <cstddef>
#include <type_traits>
namespace rtc {
// Determines if the given class has zero-argument .data() and .size() methods
// whose return values are convertible to T* and size_t, respectively.
template <typename DS, typename T>
class HasDataAndSize {
template <
typename C,
typename std::enable_if<
std::is_convertible<decltype(std::declval<C>().data()), T*>::value &&
std::size_t>::value>::type* = nullptr>
static int Test(int);
template <typename>
static char Test(...);
static constexpr bool value = std::is_same<decltype(Test<DS>(0)), int>::value;
namespace test_has_data_and_size {
template <typename DR, typename SR>
struct Test1 {
DR data();
SR size();
static_assert(HasDataAndSize<Test1<int*, int>, int>::value, "");
static_assert(HasDataAndSize<Test1<int*, int>, const int>::value, "");
static_assert(HasDataAndSize<Test1<const int*, int>, const int>::value, "");
static_assert(!HasDataAndSize<Test1<const int*, int>, int>::value,
"implicit cast of const int* to int*");
static_assert(!HasDataAndSize<Test1<char*, size_t>, int>::value,
"implicit cast of char* to int*");
struct Test2 {
int* data;
size_t size;
static_assert(!HasDataAndSize<Test2, int>::value,
".data and .size aren't functions");
struct Test3 {
int* data();
static_assert(!HasDataAndSize<Test3, int>::value, ".size() is missing");
class Test4 {
int* data();
size_t size();
static_assert(!HasDataAndSize<Test4, int>::value,
".data() and .size() are private");
} // namespace test_has_data_and_size
} // namespace rtc