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
|
#ifndef shared_string_hh_INCLUDED
#define shared_string_hh_INCLUDED
#include "string.hh"
#include "ref_ptr.hh"
#include "utils.hh"
#include "hash_map.hh"
#include <numeric>
#include <cstring>
namespace Kakoune
{
struct StringData : UseMemoryDomain<MemoryDomain::SharedString>
{
uint32_t refcount;
const int length;
[[gnu::always_inline]]
const char* data() const { return reinterpret_cast<const char*>(this + 1); }
[[gnu::always_inline]]
StringView strview() const { return {data(), length}; }
private:
StringData(int len) : refcount(0), length(len) {}
static constexpr uint32_t interned_flag = 1u << 31;
static constexpr uint32_t refcount_mask = ~interned_flag;
struct PtrPolicy
{
static void inc_ref(StringData* r, void*) noexcept { ++r->refcount; }
static void dec_ref(StringData* r, void*) noexcept
{
if ((--r->refcount & refcount_mask) > 0)
return;
if (r->refcount & interned_flag)
Registry::instance().remove(r->strview());
StringData::operator delete(r, sizeof(StringData) + r->length + 1);
}
static void ptr_moved(StringData*, void*, void*) noexcept {}
};
public:
using Ptr = RefPtr<StringData, PtrPolicy>;
class Registry : public Singleton<Registry>
{
public:
void debug_stats() const;
Ptr intern(StringView str);
Ptr intern(StringView str, size_t hash);
void remove(StringView str);
private:
HashMap<StringView, StringData*, MemoryDomain::SharedString> m_strings;
};
static Ptr create(ConvertibleTo<StringView> auto&&... strs)
{
const int len = ((int)StringView{strs}.length() + ...);
void* ptr = StringData::operator new(sizeof(StringData) + len + 1);
auto* res = new (ptr) StringData(len);
auto* data = reinterpret_cast<char*>(res + 1);
auto append = [&](StringView str) {
if (str.empty()) // memccpy(..., nullptr, 0) is UB
return;
memcpy(data, str.begin(), (size_t)str.length());
data += (int)str.length();
};
(append(strs), ...);
*data = 0;
return RefPtr<StringData, PtrPolicy>{res};
}
};
using StringDataPtr = StringData::Ptr;
using StringRegistry = StringData::Registry;
inline StringDataPtr intern(StringView str) { return StringRegistry::instance().intern(str); }
inline StringDataPtr intern(StringView str, size_t hash) { return StringRegistry::instance().intern(str, hash); }
}
#endif // shared_string_hh_INCLUDED
|
