kakoune/src/shared_string.hh
Maxime Coste 296ab1a1ff Improve WordDB performance by precomputing hashes
Avoid multiple computation of string hashes by making it possible
to pre-compute and pass hashes to interned strings and hash maps.
2023-11-17 17:01:51 +11:00

72 lines
2.0 KiB
C++

#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>
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)
{
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(ArrayView<const StringView> strs);
};
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