horrible_cast

Author: mutouyun

src/ipc.cpp

@@ -32,8 +32,8 @@
 
 namespace {
 
-using msg_id_t   = std::uint32_t;
-using acc_t      = std::atomic<msg_id_t>;
+using msg_id_t = std::uint32_t;
+using acc_t    = std::atomic<msg_id_t>;
 
 template <std::size_t DataSize, std::size_t AlignSize>
 struct msg_t;
@@ -505,8 +505,8 @@ static ipc::buff_t recv(ipc::handle_t h, std::size_t tm) {
             if (buf != nullptr) {
                 if (recycled) {
                     return ipc::buff_t{buf, msg_size, [](void* pmid, std::size_t size) {
-                        release_storage(reinterpret_cast<ipc::storage_id_t>(pmid) - 1, size);
-                    }, reinterpret_cast<void*>(buf_id + 1)};
+                        release_storage(ipc::detail::horrible_cast<ipc::storage_id_t>(pmid) - 1, size);
+                    }, ipc::detail::horrible_cast<void*>(buf_id + 1)};
                 } else {
                     return ipc::buff_t{buf, msg_size}; // no recycle
                 }

src/libipc/platform/detail.h

@@ -111,5 +111,17 @@ constexpr const T& (min)(const T& a, const T& b) {
 
 #endif/*__cplusplus < 201703L*/
 
+template <typename T, typename U>
+auto horrible_cast(U rhs) noexcept
+    -> typename std::enable_if<std::is_trivially_copyable<T>::value
+                            && std::is_trivially_copyable<U>::value, T>::type {
+    union {
+        T t;
+        U u;
+    } r = {};
+    r.u = rhs;
+    return r.t;
+}
+
 } // namespace detail
 } // namespace ipc