aboutsummaryrefslogtreecommitdiff
path: root/src/common/range_map.h
blob: 79c7ef547419d58fe2896b3b496c8c9baf6c71b1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
// SPDX-License-Identifier: GPL-3.0-or-later

#pragma once

#include <map>
#include <type_traits>

#include "common/common_types.h"

namespace Common {

template <typename KeyTBase, typename ValueT>
class RangeMap {
private:
    using KeyT =
        std::conditional_t<std::is_signed_v<KeyTBase>, KeyTBase, std::make_signed_t<KeyTBase>>;

public:
    explicit RangeMap(ValueT null_value_) : null_value{null_value_} {
        container.emplace(std::numeric_limits<KeyT>::min(), null_value);
    };
    ~RangeMap() = default;

    void Map(KeyTBase address, KeyTBase address_end, ValueT value) {
        KeyT new_address = static_cast<KeyT>(address);
        KeyT new_address_end = static_cast<KeyT>(address_end);
        if (new_address < 0) {
            new_address = 0;
        }
        if (new_address_end < 0) {
            new_address_end = 0;
        }
        InternalMap(new_address, new_address_end, value);
    }

    void Unmap(KeyTBase address, KeyTBase address_end) {
        Map(address, address_end, null_value);
    }

    [[nodiscard]] size_t GetContinousSizeFrom(KeyTBase address) const {
        const KeyT new_address = static_cast<KeyT>(address);
        if (new_address < 0) {
            return 0;
        }
        return ContinousSizeInternal(new_address);
    }

    [[nodiscard]] ValueT GetValueAt(KeyT address) const {
        const KeyT new_address = static_cast<KeyT>(address);
        if (new_address < 0) {
            return null_value;
        }
        return GetValueInternal(new_address);
    }

private:
    using MapType = std::map<KeyT, ValueT>;
    using IteratorType = typename MapType::iterator;
    using ConstIteratorType = typename MapType::const_iterator;

    size_t ContinousSizeInternal(KeyT address) const {
        const auto it = GetFirstElementBeforeOrOn(address);
        if (it == container.end() || it->second == null_value) {
            return 0;
        }
        const auto it_end = std::next(it);
        if (it_end == container.end()) {
            return std::numeric_limits<KeyT>::max() - address;
        }
        return it_end->first - address;
    }

    ValueT GetValueInternal(KeyT address) const {
        const auto it = GetFirstElementBeforeOrOn(address);
        if (it == container.end()) {
            return null_value;
        }
        return it->second;
    }

    ConstIteratorType GetFirstElementBeforeOrOn(KeyT address) const {
        auto it = container.lower_bound(address);
        if (it == container.begin()) {
            return it;
        }
        if (it != container.end() && (it->first == address)) {
            return it;
        }
        --it;
        return it;
    }

    ValueT GetFirstValueWithin(KeyT address) {
        auto it = container.lower_bound(address);
        if (it == container.begin()) {
            return it->second;
        }
        if (it == container.end()) [[unlikely]] { // this would be a bug
            return null_value;
        }
        --it;
        return it->second;
    }

    ValueT GetLastValueWithin(KeyT address) {
        auto it = container.upper_bound(address);
        if (it == container.end()) {
            return null_value;
        }
        if (it == container.begin()) [[unlikely]] { // this would be a bug
            return it->second;
        }
        --it;
        return it->second;
    }

    void InternalMap(KeyT address, KeyT address_end, ValueT value) {
        const bool must_add_start = GetFirstValueWithin(address) != value;
        const ValueT last_value = GetLastValueWithin(address_end);
        const bool must_add_end = last_value != value;
        auto it = container.lower_bound(address);
        const auto it_end = container.upper_bound(address_end);
        while (it != it_end) {
            it = container.erase(it);
        }
        if (must_add_start) {
            container.emplace(address, value);
        }
        if (must_add_end) {
            container.emplace(address_end, last_value);
        }
    }

    ValueT null_value;
    MapType container;
};

} // namespace Common