1 // Copyright 2018 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef V8_BASE_ADDRESS_REGION_H_
6 #define V8_BASE_ADDRESS_REGION_H_
7
8 #include <iostream>
9
10 #include "src/base/macros.h"
11
12 namespace v8 {
13 namespace base {
14
15 // Helper class representing an address region of certain size.
16 class AddressRegion {
17 public:
18 // Function object that compares the start address of two regions. Usable as
19 // compare function on std data structures and algorithms.
20 struct StartAddressLess {
operatorStartAddressLess21 bool operator()(base::AddressRegion a, base::AddressRegion b) const {
22 return a.begin() < b.begin();
23 }
24 };
25
26 using Address = uintptr_t;
27
28 constexpr AddressRegion() = default;
29
AddressRegion(Address address,size_t size)30 constexpr AddressRegion(Address address, size_t size)
31 : address_(address), size_(size) {}
32
begin()33 Address begin() const { return address_; }
end()34 Address end() const { return address_ + size_; }
35
size()36 size_t size() const { return size_; }
set_size(size_t size)37 void set_size(size_t size) { size_ = size; }
38
is_empty()39 bool is_empty() const { return size_ == 0; }
40
contains(Address address)41 bool contains(Address address) const {
42 STATIC_ASSERT(std::is_unsigned<Address>::value);
43 return (address - begin()) < size();
44 }
45
contains(Address address,size_t size)46 bool contains(Address address, size_t size) const {
47 STATIC_ASSERT(std::is_unsigned<Address>::value);
48 Address offset = address - begin();
49 return (offset < size_) && (offset + size <= size_);
50 }
51
contains(AddressRegion region)52 bool contains(AddressRegion region) const {
53 return contains(region.address_, region.size_);
54 }
55
GetOverlap(AddressRegion region)56 base::AddressRegion GetOverlap(AddressRegion region) const {
57 Address overlap_start = std::max(begin(), region.begin());
58 Address overlap_end =
59 std::max(overlap_start, std::min(end(), region.end()));
60 return {overlap_start, overlap_end - overlap_start};
61 }
62
63 bool operator==(AddressRegion other) const {
64 return address_ == other.address_ && size_ == other.size_;
65 }
66
67 bool operator!=(AddressRegion other) const {
68 return address_ != other.address_ || size_ != other.size_;
69 }
70
71 private:
72 Address address_ = 0;
73 size_t size_ = 0;
74 };
75 ASSERT_TRIVIALLY_COPYABLE(AddressRegion);
76
77 // Construct an AddressRegion from anything providing a {data()} and {size()}
78 // accessor.
79 template <typename Container,
80 typename = decltype(std::declval<Container>().data()),
81 typename = decltype(std::declval<Container>().size())>
AddressRegionOf(Container && c)82 inline constexpr AddressRegion AddressRegionOf(Container&& c) {
83 return AddressRegion{reinterpret_cast<AddressRegion::Address>(c.data()),
84 sizeof(*c.data()) * c.size()};
85 }
86
87 inline std::ostream& operator<<(std::ostream& out, AddressRegion region) {
88 return out << "[" << reinterpret_cast<void*>(region.begin()) << "+"
89 << region.size() << "]";
90 }
91
92 } // namespace base
93 } // namespace v8
94
95 #endif // V8_BASE_ADDRESS_REGION_H_
96