jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#pragma once
8
9#include <AK/Badge.h>
10#include <AK/RefCounted.h>
11#include <AK/RefPtr.h>
12#include <AK/Span.h>
13#include <AK/Types.h>
14#include <AK/kmalloc.h>
15
16namespace AK {
17
18enum ShouldChomp {
19 NoChomp,
20 Chomp
21};
22
23size_t allocation_size_for_stringimpl(size_t length);
24
25class StringImpl : public RefCounted<StringImpl> {
26public:
27 static NonnullRefPtr<StringImpl const> create_uninitialized(size_t length, char*& buffer);
28 static RefPtr<StringImpl const> create(char const* cstring, ShouldChomp = NoChomp);
29 static RefPtr<StringImpl const> create(char const* cstring, size_t length, ShouldChomp = NoChomp);
30 static RefPtr<StringImpl const> create(ReadonlyBytes, ShouldChomp = NoChomp);
31 static RefPtr<StringImpl const> create_lowercased(char const* cstring, size_t length);
32 static RefPtr<StringImpl const> create_uppercased(char const* cstring, size_t length);
33
34 NonnullRefPtr<StringImpl const> to_lowercase() const;
35 NonnullRefPtr<StringImpl const> to_uppercase() const;
36
37 void operator delete(void* ptr)
38 {
39 kfree_sized(ptr, allocation_size_for_stringimpl(static_cast<StringImpl*>(ptr)->m_length));
40 }
41
42 static StringImpl& the_empty_stringimpl();
43
44 ~StringImpl();
45
46 size_t length() const { return m_length; }
47 // Includes NUL-terminator.
48 char const* characters() const { return &m_inline_buffer[0]; }
49
50 ALWAYS_INLINE ReadonlyBytes bytes() const { return { characters(), length() }; }
51 ALWAYS_INLINE StringView view() const { return { characters(), length() }; }
52
53 char const& operator[](size_t i) const
54 {
55 VERIFY(i < m_length);
56 return characters()[i];
57 }
58
59 bool operator==(StringImpl const& other) const
60 {
61 if (length() != other.length())
62 return false;
63 return __builtin_memcmp(characters(), other.characters(), length()) == 0;
64 }
65
66 unsigned hash() const
67 {
68 if (!m_has_hash)
69 compute_hash();
70 return m_hash;
71 }
72
73 unsigned existing_hash() const
74 {
75 return m_hash;
76 }
77
78 unsigned case_insensitive_hash() const;
79
80 bool is_fly() const { return m_fly; }
81 void set_fly(Badge<DeprecatedFlyString>, bool fly) const { m_fly = fly; }
82
83private:
84 enum ConstructTheEmptyStringImplTag {
85 ConstructTheEmptyStringImpl
86 };
87 explicit StringImpl(ConstructTheEmptyStringImplTag)
88 : m_fly(true)
89 {
90 m_inline_buffer[0] = '\0';
91 }
92
93 enum ConstructWithInlineBufferTag {
94 ConstructWithInlineBuffer
95 };
96 StringImpl(ConstructWithInlineBufferTag, size_t length);
97
98 void compute_hash() const;
99
100 size_t m_length { 0 };
101 mutable unsigned m_hash { 0 };
102 mutable bool m_has_hash { false };
103 mutable bool m_fly { false };
104 char m_inline_buffer[0];
105};
106
107inline size_t allocation_size_for_stringimpl(size_t length)
108{
109 return sizeof(StringImpl) + (sizeof(char) * length) + sizeof(char);
110}
111
112template<>
113struct Formatter<StringImpl> : Formatter<StringView> {
114 ErrorOr<void> format(FormatBuilder& builder, StringImpl const& value)
115 {
116 return Formatter<StringView>::format(builder, { value.characters(), value.length() });
117 }
118};
119
120}
121
122#if USING_AK_GLOBALLY
123using AK::Chomp;
124using AK::NoChomp;
125using AK::StringImpl;
126#endif