1/*
2 * Copyright 2016-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#pragma once
18
19#include <cmath>
20
21namespace folly {
22
23#ifndef __ANDROID__
24
25/**
26 * Most platforms hopefully provide std::nextafter.
27 */
28
29/* using override */ using std::nextafter;
30
31#else // !__ANDROID__
32
33/**
34 * On Android, std::nextafter isn't implemented. However, the C functions and
35 * compiler builtins are still provided. Using the GCC builtin is actually
36 * slightly faster, as they're constexpr and the use cases within folly are in
37 * constexpr context.
38 */
39
40#if defined(__GNUC__) && !defined(__clang__)
41
42constexpr float nextafter(float x, float y) {
43 return __builtin_nextafterf(x, y);
44}
45
46constexpr double nextafter(double x, double y) {
47 return __builtin_nextafter(x, y);
48}
49
50constexpr long double nextafter(long double x, long double y) {
51 return __builtin_nextafterl(x, y);
52}
53
54#else // __GNUC__
55
56inline float nextafter(float x, float y) {
57 return ::nextafterf(x, y);
58}
59
60inline double nextafter(double x, double y) {
61 return ::nextafter(x, y);
62}
63
64inline long double nextafter(long double x, long double y) {
65 return ::nextafterl(x, y);
66}
67
68#endif // __GNUC__
69
70#endif // __ANDROID__
71} // namespace folly
72