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 "BAssert.h"
30#include <algorithm>
31#include <cstdint>
32#include <cstddef>
33#include <limits>
34#include <string.h>
35#include <type_traits>
36#include <chrono>
37
38namespace bmalloc {
39
40// Versions of min and max that are compatible with compile-time constants.
41template<typename T> constexpr T max(T a, T b)
42{
43 return a > b ? a : b;
44}
45
46template<typename T> constexpr T min(T a, T b)
47{
48 return a < b ? a : b;
49}
50
51template<typename T> constexpr T mask(T value, uintptr_t mask)
52{
53 static_assert(sizeof(T) == sizeof(uintptr_t), "sizeof(T) must be equal to sizeof(uintptr_t).");
54 return static_cast<T>(static_cast<uintptr_t>(value) & mask);
55}
56
57template<typename T> inline T* mask(T* value, uintptr_t mask)
58{
59 return reinterpret_cast<T*>(reinterpret_cast<uintptr_t>(value) & mask);
60}
61
62template<typename T> constexpr bool test(T value, uintptr_t mask)
63{
64 return !!(reinterpret_cast<uintptr_t>(value) & mask);
65}
66
67template <typename T>
68constexpr bool isPowerOfTwo(T size)
69{
70 static_assert(std::is_integral<T>::value, "");
71 return size && !(size & (size - 1));
72}
73
74template<typename T> constexpr T roundUpToMultipleOfImpl(size_t divisor, T x)
75{
76 static_assert(sizeof(T) == sizeof(uintptr_t), "sizeof(T) must be equal to sizeof(uintptr_t).");
77 return static_cast<T>((static_cast<uintptr_t>(x) + (divisor - 1)) & ~(divisor - 1));
78}
79
80template<typename T> inline T roundUpToMultipleOf(size_t divisor, T x)
81{
82 BASSERT(isPowerOfTwo(divisor));
83 return roundUpToMultipleOfImpl(divisor, x);
84}
85
86template<size_t divisor, typename T> constexpr T roundUpToMultipleOf(T x)
87{
88 static_assert(isPowerOfTwo(divisor), "'divisor' must be a power of two.");
89 return roundUpToMultipleOfImpl(divisor, x);
90}
91
92template<typename T> inline T* roundUpToMultipleOf(size_t divisor, T* x)
93{
94 BASSERT(isPowerOfTwo(divisor));
95 return reinterpret_cast<T*>((reinterpret_cast<uintptr_t>(x) + (divisor - 1)) & ~(divisor - 1));
96}
97
98template<size_t divisor, typename T> inline T* roundUpToMultipleOf(T* x)
99{
100 static_assert(isPowerOfTwo(divisor), "'divisor' must be a power of two.");
101 return roundUpToMultipleOf(divisor, x);
102}
103
104template<typename T> inline T roundDownToMultipleOf(size_t divisor, T x)
105{
106 BASSERT(isPowerOfTwo(divisor));
107 static_assert(sizeof(T) == sizeof(uintptr_t), "sizeof(T) must be equal to sizeof(uintptr_t).");
108 return static_cast<T>(mask(static_cast<uintptr_t>(x), ~(divisor - 1ul)));
109}
110
111template<typename T> inline T* roundDownToMultipleOf(size_t divisor, T* x)
112{
113 BASSERT(isPowerOfTwo(divisor));
114 return reinterpret_cast<T*>(mask(reinterpret_cast<uintptr_t>(x), ~(divisor - 1ul)));
115}
116
117template<size_t divisor, typename T> constexpr T roundDownToMultipleOf(T x)
118{
119 static_assert(isPowerOfTwo(divisor), "'divisor' must be a power of two.");
120 return roundDownToMultipleOf(divisor, x);
121}
122
123template<typename T> inline void divideRoundingUp(T numerator, T denominator, T& quotient, T& remainder)
124{
125 // We expect the compiler to emit a single divide instruction to extract both the quotient and the remainder.
126 quotient = numerator / denominator;
127 remainder = numerator % denominator;
128 if (remainder)
129 quotient += 1;
130}
131
132template<typename T> inline T divideRoundingUp(T numerator, T denominator)
133{
134 return (numerator + denominator - 1) / denominator;
135}
136
137template<typename T> inline T roundUpToMultipleOfNonPowerOfTwo(size_t divisor, T x)
138{
139 return divideRoundingUp(x, divisor) * divisor;
140}
141
142// Version of sizeof that returns 0 for empty classes.
143
144template<typename T> constexpr size_t sizeOf()
145{
146 return std::is_empty<T>::value ? 0 : sizeof(T);
147}
148
149template<typename T> constexpr size_t bitCount()
150{
151 return sizeof(T) * 8;
152}
153
154#if BOS(WINDOWS)
155template<int depth> __forceinline constexpr unsigned long clzl(unsigned long value)
156{
157 return value & (1UL << (bitCount<unsigned long>() - 1)) ? 0 : 1 + clzl<depth - 1>(value << 1);
158}
159
160template<> __forceinline constexpr unsigned long clzl<1>(unsigned long value)
161{
162 return 0;
163}
164
165__forceinline constexpr unsigned long __builtin_clzl(unsigned long value)
166{
167 return value == 0 ? 32 : clzl<bitCount<unsigned long>()>(value);
168}
169#endif
170
171constexpr unsigned long log2(unsigned long value)
172{
173 return bitCount<unsigned long>() - 1 - __builtin_clzl(value);
174}
175
176#define BOFFSETOF(class, field) (reinterpret_cast<ptrdiff_t>(&(reinterpret_cast<class*>(0x4000)->field)) - 0x4000)
177
178template<typename T>
179bool findBitInWord(T word, size_t& index, size_t endIndex, bool value)
180{
181 static_assert(std::is_unsigned<T>::value, "Type used in findBitInWord must be unsigned");
182
183 word >>= index;
184
185 while (index < endIndex) {
186 if ((word & 1) == static_cast<T>(value))
187 return true;
188 index++;
189 word >>= 1;
190 }
191
192 index = endIndex;
193 return false;
194}
195
196} // namespace bmalloc
197
198#endif // Algorithm_h
199