1 /*
2 * Copyright (C) 2017 The Android Open Source Project
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 #ifndef INCLUDE_PERFETTO_BASE_UTILS_H_
18 #define INCLUDE_PERFETTO_BASE_UTILS_H_
19
20 #include <errno.h>
21 #include <stddef.h>
22 #include <stdlib.h>
23
24 #define PERFETTO_EINTR(x) \
25 ({ \
26 decltype(x) eintr_wrapper_result; \
27 do { \
28 eintr_wrapper_result = (x); \
29 } while (eintr_wrapper_result == -1 && errno == EINTR); \
30 eintr_wrapper_result; \
31 })
32
33 #define PERFETTO_LIKELY(_x) __builtin_expect(!!(_x), 1)
34 #define PERFETTO_UNLIKELY(_x) __builtin_expect(!!(_x), 0)
35
36 namespace perfetto {
37 namespace base {
38
39 constexpr size_t kPageSize = 4096;
40
41 template <typename T>
ArraySize(const T & array)42 constexpr size_t ArraySize(const T& array) {
43 return sizeof(array) / sizeof(array[0]);
44 }
45
46 template <typename... T>
ignore_result(const T &...)47 inline void ignore_result(const T&...) {}
48
49 // Function object which invokes 'free' on its parameter, which must be
50 // a pointer. Can be used to store malloc-allocated pointers in std::unique_ptr:
51 //
52 // std::unique_ptr<int, base::FreeDeleter> foo_ptr(
53 // static_cast<int*>(malloc(sizeof(int))));
54 struct FreeDeleter {
operatorFreeDeleter55 inline void operator()(void* ptr) const { free(ptr); }
56 };
57
58 template <typename T>
AssumeLittleEndian(T value)59 constexpr T AssumeLittleEndian(T value) {
60 static_assert(__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__,
61 "Unimplemented on big-endian archs");
62 return value;
63 }
64
65 // Round up |size| to a multiple of |alignment| (must be a power of two).
66 template <size_t alignment>
AlignUp(size_t size)67 constexpr size_t AlignUp(size_t size) {
68 static_assert((alignment & (alignment - 1)) == 0, "alignment must be a pow2");
69 return (size + alignment - 1) & ~(alignment - 1);
70 }
71
72 } // namespace base
73 } // namespace perfetto
74
75 #endif // INCLUDE_PERFETTO_BASE_UTILS_H_
76