1/*
2 * Copyright (C) 2014 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef Algorithm_h
27#define Algorithm_h
28
29#include "Algorithm.h"
30#include <algorithm>
31#include <cstdint>
32#include <cstddef>
33#include <limits>
34#include <type_traits>
35#include <chrono>
36
37namespace bmalloc {
38
39// Versions of min and max that are compatible with compile-time constants.
40template<typename T> inline constexpr T max(T a, T b)
41{
42    return a > b ? a : b;
43}
44
45template<typename T> inline constexpr T min(T a, T b)
46{
47    return a < b ? a : b;
48}
49
50template<typename T> inline constexpr T mask(T value, uintptr_t mask)
51{
52    return reinterpret_cast<T>(reinterpret_cast<uintptr_t>(value) & mask);
53}
54
55template<typename T> inline constexpr bool test(T value, uintptr_t mask)
56{
57    return !!(reinterpret_cast<uintptr_t>(value) & mask);
58}
59
60template<size_t divisor, typename T> inline constexpr T roundUpToMultipleOf(T x)
61{
62    static_assert(divisor && !(divisor & (divisor - 1)), "'divisor' must be a power of two.");
63    return reinterpret_cast<T>((reinterpret_cast<uintptr_t>(x) + (divisor - 1ul)) & ~(divisor - 1ul));
64}
65
66template<size_t divisor, typename T> inline constexpr T roundDownToMultipleOf(T x)
67{
68    static_assert(divisor && !(divisor & (divisor - 1)), "'divisor' must be a power of two.");
69    return reinterpret_cast<T>(mask(reinterpret_cast<uintptr_t>(x), ~(divisor - 1ul)));
70}
71
72// Version of sizeof that returns 0 for empty classes.
73
74template<typename T> inline constexpr size_t sizeOf()
75{
76    return std::is_empty<T>::value ? 0 : sizeof(T);
77}
78
79template<typename T> inline constexpr size_t bitCount()
80{
81    return sizeof(T) * 8;
82}
83
84inline constexpr bool isPowerOfTwo(size_t size)
85{
86    return !(size & (size - 1));
87}
88
89} // namespace bmalloc
90
91#endif // Algorithm_h
92