kakoune/src/shared_string.cc
Maxime Coste d076c033e7 Avoid calling memcpy from empty string views
ubsan is unhappy when passing a nullptr as the source pointer to
memcpy even if the length is 0.

Fixes #4720
2022-08-21 17:52:51 +02:00

62 lines
1.7 KiB
C++

#include "shared_string.hh"
#include "buffer_utils.hh"
#include <cstring>
namespace Kakoune
{
StringDataPtr StringData::create(ArrayView<const StringView> strs)
{
const int len = accumulate(strs, 0, [](int l, StringView s) {
return l + (int)s.length();
});
void* ptr = StringData::operator new(sizeof(StringData) + len + 1);
auto* res = new (ptr) StringData(len);
auto* data = reinterpret_cast<char*>(res + 1);
for (auto& str : strs)
{
if (str.length() == 0) // memccpy(..., nullptr, 0) is UB
continue;
memcpy(data, str.begin(), (size_t)str.length());
data += (int)str.length();
}
*data = 0;
return RefPtr<StringData, PtrPolicy>{res};
}
StringDataPtr StringData::Registry::intern(StringView str)
{
auto it = m_strings.find(str);
if (it != m_strings.end())
return StringDataPtr{it->value};
auto data = StringData::create(str);
data->refcount |= interned_flag;
m_strings.insert({data->strview(), data.get()});
return data;
}
void StringData::Registry::remove(StringView str)
{
kak_assert(m_strings.contains(str));
m_strings.unordered_remove(str);
}
void StringData::Registry::debug_stats() const
{
write_to_debug_buffer("Shared Strings stats:");
size_t total_refcount = 0;
size_t total_size = 0;
size_t count = m_strings.size();
for (auto& st : m_strings)
{
total_refcount += (st.value->refcount & refcount_mask) - 1;
total_size += (int)st.value->length;
}
write_to_debug_buffer(format(" data size: {}, mean: {}", total_size, (float)total_size/count));
write_to_debug_buffer(format(" refcounts: {}, mean: {}", total_refcount, (float)total_refcount/count));
}
}