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use atomic exchange

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This commit is contained in:
Daniel Kolesa 2022-04-21 21:54:36 +02:00
parent 7601680055
commit 93dc2e07d3
2 changed files with 17 additions and 6 deletions
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18
src/cs_ident.cc
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@ -24,6 +24,13 @@ static inline void var_store(unsigned char *base, T v) noexcept {
p->store(v);
}
template<typename T>
static inline T var_exchange(unsigned char const *base, T v) noexcept {
atomic_type<T> *p{};
std::memcpy(&p, &base, sizeof(void *));
return p->exchange(v);
}
/* the ctors are non-atomic; that's okay, these are called during ident
* creation before anything is stored, so there is no chance of data race
*/
@ -60,16 +67,14 @@ static inline void var_save(
) noexcept {
switch (v.type()) {
case value_type::INTEGER:
var_store<integer_type>(top, var_load<integer_type>(fromp));
var_store<integer_type>(fromp, 0);
var_store<integer_type>(top, var_exchange<integer_type>(fromp, 0));
return;
case value_type::FLOAT: {
using FST = typename var_value::FS;
FST vs{};
float_type fv = 0;
std::memcpy(&vs, &fv, sizeof(fv));
var_store<FST>(top, var_load<FST>(fromp));
var_store<FST>(fromp, vs);
var_store<FST>(top, var_exchange<FST>(fromp, vs));
return;
}
case value_type::STRING: {
@ -77,8 +82,9 @@ static inline void var_save(
if (p) {
str_managed_unref(p);
}
var_store<char const *>(top, var_load<char const *>(fromp));
var_store<char const *>(fromp, nullptr);
var_store<char const *>(
top, var_exchange<char const *>(fromp, nullptr)
);
}
default:
break;

5
src/cs_lock.hh
View file

@ -6,6 +6,8 @@
#if LIBCUBESCRIPT_CONF_THREAD_SAFE
#include <mutex>
#include <atomic>
#else
#include <utility>
#endif
namespace cubescript {
@ -27,6 +29,9 @@ struct atomic_type {
void store(T v) {
p_v = v;
}
T exchange(T v) {
return std::exchange(p_v, v);
}
};
#else