move concept & pimpl helpers to single header respectively

include/def.h

@@ -3,7 +3,6 @@
 #include <cstddef>
 #include <cstdint>
 #include <limits>
-#include <type_traits>
 #include <new>
 #include <utility>
 
@@ -47,65 +46,4 @@ enum class trans { // transmission
 template <relat Rp, relat Rc, trans Ts>
 struct wr {};
 
-// concept helpers
-
-template <bool Cond, typename R>
-using Requires = std::enable_if_t<Cond, R>;
-
-// pimpl small object optimization helpers
-
-template <typename T, typename R = T*>
-using IsImplComfortable = Requires<(sizeof(T) <= sizeof(T*)), R>;
-
-template <typename T, typename R = T*>
-using IsImplUncomfortable = Requires<(sizeof(T) > sizeof(T*)), R>;
-
-template <typename T, typename... P>
-constexpr auto make_impl(P&&... params) -> IsImplComfortable<T> {
-    T* buf {};
-    ::new (&buf) T { std::forward<P>(params)... };
-    return buf;
-}
-
-template <typename T>
-constexpr auto impl(T* const (& p)) -> IsImplComfortable<T> {
-    return reinterpret_cast<T*>(&const_cast<char &>(reinterpret_cast<char const &>(p)));
-}
-
-template <typename T>
-constexpr auto clear_impl(T* p) -> IsImplComfortable<T, void> {
-    if (p != nullptr) impl(p)->~T();
-}
-
-template <typename T, typename... P>
-constexpr auto make_impl(P&&... params) -> IsImplUncomfortable<T> {
-    return new T { std::forward<P>(params)... };
-}
-
-template <typename T>
-constexpr auto clear_impl(T* p) -> IsImplUncomfortable<T, void> {
-    delete p;
-}
-
-template <typename T>
-constexpr auto impl(T* const (& p)) -> IsImplUncomfortable<T> {
-    return p;
-}
-
-template <typename T>
-struct pimpl {
-    template <typename... P>
-    constexpr static T* make(P&&... params) {
-        return make_impl<T>(std::forward<P>(params)...);
-    }
-
-#if __cplusplus >= 201703L
-    constexpr void clear() {
-#else /*__cplusplus < 201703L*/
-    void clear() {
-#endif/*__cplusplus < 201703L*/
-        clear_impl(static_cast<T*>(const_cast<pimpl*>(this)));
-    }
-};
-
 } // namespace ipc

src/buffer.cpp

@@ -1,4 +1,5 @@
 #include "buffer.h"
+#include "pimpl.h"
 
 #include <cstring>
 

src/concept.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <type_traits>
+
+namespace ipc {
+
+// concept helpers
+
+template <bool Cond, typename R>
+using Requires = std::enable_if_t<Cond, R>;
+
+} // namespace ipc

src/pimpl.h

@@ -0,0 +1,66 @@
+#pragma once
+
+#include <new>
+#include <utility>
+
+#include "concept.h"
+
+namespace ipc {
+
+// pimpl small object optimization helpers
+
+template <typename T, typename R = T*>
+using IsImplComfortable = Requires<(sizeof(T) <= sizeof(T*)), R>;
+
+template <typename T, typename R = T*>
+using IsImplUncomfortable = Requires<(sizeof(T) > sizeof(T*)), R>;
+
+template <typename T, typename... P>
+constexpr auto make_impl(P&&... params) -> IsImplComfortable<T> {
+    T* buf {};
+    ::new (&buf) T { std::forward<P>(params)... };
+    return buf;
+}
+
+template <typename T>
+constexpr auto impl(T* const (& p)) -> IsImplComfortable<T> {
+    return reinterpret_cast<T*>(&const_cast<char &>(reinterpret_cast<char const &>(p)));
+}
+
+template <typename T>
+constexpr auto clear_impl(T* p) -> IsImplComfortable<T, void> {
+    if (p != nullptr) impl(p)->~T();
+}
+
+template <typename T, typename... P>
+constexpr auto make_impl(P&&... params) -> IsImplUncomfortable<T> {
+    return new T { std::forward<P>(params)... };
+}
+
+template <typename T>
+constexpr auto clear_impl(T* p) -> IsImplUncomfortable<T, void> {
+    delete p;
+}
+
+template <typename T>
+constexpr auto impl(T* const (& p)) -> IsImplUncomfortable<T> {
+    return p;
+}
+
+template <typename T>
+struct pimpl {
+    template <typename... P>
+    constexpr static T* make(P&&... params) {
+        return make_impl<T>(std::forward<P>(params)...);
+    }
+
+#if __cplusplus >= 201703L
+    constexpr void clear() {
+#else /*__cplusplus < 201703L*/
+    void clear() {
+#endif/*__cplusplus < 201703L*/
+        clear_impl(static_cast<T*>(const_cast<pimpl*>(this)));
+    }
+};
+
+} // namespace ipc

src/platform/to_tchar.h

@@ -9,7 +9,7 @@
 #include <algorithm>
 #include <cstring>
 
-#include "def.h"
+#include "concept.h"
 
 namespace ipc::detail {
 

src/shm.cpp

@@ -3,7 +3,7 @@
 #include <string>
 #include <utility>
 
-#include "def.h"
+#include "pimpl.h"
 
 namespace ipc {
 namespace shm {

src/waiter.cpp

@@ -2,7 +2,7 @@
 
 #include <string>
 
-#include "def.h"
+#include "pimpl.h"
 #include "platform/waiter_wrapper.h"
 
 #undef IPC_PP_CAT_