summaryrefslogtreecommitdiff
path: root/AK/Span.h
blob: 19f4d59710c995d43de050a47539d0e39de14bcd (plain)
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
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
/*
 * Copyright (c) 2020-2021, the SerenityOS developers.
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/Assertions.h>
#include <AK/Iterator.h>
#include <AK/TypedTransfer.h>
#include <AK/Types.h>

namespace AK {

namespace Detail {

template<typename T>
class Span {
public:
    ALWAYS_INLINE constexpr Span() = default;

    ALWAYS_INLINE constexpr Span(T* values, size_t size)
        : m_values(values)
        , m_size(size)
    {
    }

    template<size_t size>
    ALWAYS_INLINE constexpr Span(T (&values)[size])
        : m_values(values)
        , m_size(size)
    {
    }

protected:
    T* m_values { nullptr };
    size_t m_size { 0 };
};

template<>
class Span<u8> {
public:
    ALWAYS_INLINE constexpr Span() = default;

    ALWAYS_INLINE constexpr Span(u8* values, size_t size)
        : m_values(values)
        , m_size(size)
    {
    }
    ALWAYS_INLINE Span(void* values, size_t size)
        : m_values(reinterpret_cast<u8*>(values))
        , m_size(size)
    {
    }

protected:
    u8* m_values { nullptr };
    size_t m_size { 0 };
};

template<>
class Span<const u8> {
public:
    ALWAYS_INLINE constexpr Span() = default;

    ALWAYS_INLINE constexpr Span(const u8* values, size_t size)
        : m_values(values)
        , m_size(size)
    {
    }
    ALWAYS_INLINE Span(const void* values, size_t size)
        : m_values(reinterpret_cast<const u8*>(values))
        , m_size(size)
    {
    }
    ALWAYS_INLINE Span(const char* values, size_t size)
        : m_values(reinterpret_cast<const u8*>(values))
        , m_size(size)
    {
    }

protected:
    const u8* m_values { nullptr };
    size_t m_size { 0 };
};

}

template<typename T>
class Span : public Detail::Span<T> {
public:
    using Detail::Span<T>::Span;

    constexpr Span() = default;

    ALWAYS_INLINE constexpr Span(const Span& other)
        : Span(other.m_values, other.m_size)
    {
    }

    ALWAYS_INLINE constexpr const T* data() const { return this->m_values; }
    ALWAYS_INLINE constexpr T* data() { return this->m_values; }

    ALWAYS_INLINE constexpr const T* offset_pointer(size_t offset) const { return this->m_values + offset; }
    ALWAYS_INLINE constexpr T* offset_pointer(size_t offset) { return this->m_values + offset; }

    using ConstIterator = SimpleIterator<const Span, const T>;
    using Iterator = SimpleIterator<Span, T>;

    constexpr ConstIterator begin() const { return ConstIterator::begin(*this); }
    constexpr Iterator begin() { return Iterator::begin(*this); }

    constexpr ConstIterator end() const { return ConstIterator::end(*this); }
    constexpr Iterator end() { return Iterator::end(*this); }

    ALWAYS_INLINE constexpr size_t size() const { return this->m_size; }
    ALWAYS_INLINE constexpr bool is_null() const { return this->m_values == nullptr; }
    ALWAYS_INLINE constexpr bool is_empty() const { return this->m_size == 0; }

    [[nodiscard]] ALWAYS_INLINE constexpr Span slice(size_t start, size_t length) const
    {
        VERIFY(start + length <= size());
        return { this->m_values + start, length };
    }
    [[nodiscard]] ALWAYS_INLINE constexpr Span slice(size_t start) const
    {
        VERIFY(start <= size());
        return { this->m_values + start, size() - start };
    }

    [[nodiscard]] ALWAYS_INLINE constexpr Span trim(size_t length) const
    {
        return { this->m_values, min(size(), length) };
    }

    ALWAYS_INLINE constexpr T* offset(size_t start) const
    {
        VERIFY(start < this->m_size);
        return this->m_values + start;
    }

    ALWAYS_INLINE constexpr void overwrite(size_t offset, const void* data, size_t data_size)
    {
        // make sure we're not told to write past the end
        VERIFY(offset + data_size <= size());
        __builtin_memcpy(this->data() + offset, data, data_size);
    }

    ALWAYS_INLINE constexpr size_t copy_to(Span<RemoveConst<T>> other) const
    {
        VERIFY(other.size() >= size());
        return TypedTransfer<RemoveConst<T>>::copy(other.data(), data(), size());
    }

    ALWAYS_INLINE constexpr size_t copy_trimmed_to(Span<RemoveConst<T>> other) const
    {
        const auto count = min(size(), other.size());
        return TypedTransfer<RemoveConst<T>>::copy(other.data(), data(), count);
    }

    ALWAYS_INLINE constexpr size_t fill(const T& value)
    {
        for (size_t idx = 0; idx < size(); ++idx)
            data()[idx] = value;

        return size();
    }

    bool constexpr contains_slow(const T& value) const
    {
        for (size_t i = 0; i < size(); ++i) {
            if (at(i) == value)
                return true;
        }
        return false;
    }

    ALWAYS_INLINE constexpr const T& at(size_t index) const
    {
        VERIFY(index < this->m_size);
        return this->m_values[index];
    }
    ALWAYS_INLINE constexpr T& at(size_t index)
    {
        VERIFY(index < this->m_size);
        return this->m_values[index];
    }

    ALWAYS_INLINE constexpr T& operator[](size_t index) const
    {
        return at(index);
    }
    ALWAYS_INLINE constexpr T& operator[](size_t index)
    {
        return at(index);
    }

    ALWAYS_INLINE constexpr Span& operator=(const Span<T>& other)
    {
        this->m_size = other.m_size;
        this->m_values = other.m_values;
        return *this;
    }

    constexpr bool operator==(Span<const T> other) const
    {
        if (size() != other.size())
            return false;

        return TypedTransfer<T>::compare(data(), other.data(), size());
    }

    ALWAYS_INLINE constexpr operator Span<const T>() const
    {
        return { data(), size() };
    }
};

using ReadonlyBytes = Span<const u8>;
using Bytes = Span<u8>;

}

using AK::Bytes;
using AK::ReadonlyBytes;
using AK::Span;