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 | |
21 | namespace 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 | |
42 | constexpr float nextafter(float x, float y) { |
43 | return __builtin_nextafterf(x, y); |
44 | } |
45 | |
46 | constexpr double nextafter(double x, double y) { |
47 | return __builtin_nextafter(x, y); |
48 | } |
49 | |
50 | constexpr long double nextafter(long double x, long double y) { |
51 | return __builtin_nextafterl(x, y); |
52 | } |
53 | |
54 | #else // __GNUC__ |
55 | |
56 | inline float nextafter(float x, float y) { |
57 | return ::nextafterf(x, y); |
58 | } |
59 | |
60 | inline double nextafter(double x, double y) { |
61 | return ::nextafter(x, y); |
62 | } |
63 | |
64 | inline 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 | |