[gjs] utils-inl: Use constexpr checks for int-to-pointer conversions

[Philip Chimento <pchimento src gnome org>]

commit ce48c3044f72f137dc172eb811050ef546aabc2f
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Sun Aug 9 01:23:40 2020 +0200

    utils-inl: Use constexpr checks for int-to-pointer conversions

 gi/utils-inl.h | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)
---
diff --git a/gi/utils-inl.h b/gi/utils-inl.h
index a258cef6..4e060c76 100644
--- a/gi/utils-inl.h
+++ b/gi/utils-inl.h
@@ -9,30 +9,26 @@
 
 #include <stdint.h>
 
-#include <type_traits>
+#include <type_traits>  // IWYU pragma: keep
 
 template <typename T>
-inline std::enable_if_t<std::is_integral_v<T> && std::is_signed_v<T>, void*>
-gjs_int_to_pointer(T v) {
-    return reinterpret_cast<void*>(static_cast<intptr_t>(v));
-}
+constexpr void* gjs_int_to_pointer(T v) {
+    static_assert(std::is_integral_v<T>, "Need integer value");
 
-template <typename T>
-inline std::enable_if_t<std::is_integral_v<T> && std::is_unsigned_v<T>, void*>
-gjs_int_to_pointer(T v) {
-    return reinterpret_cast<void*>(static_cast<uintptr_t>(v));
+    if constexpr (std::is_signed_v<T>)
+        return reinterpret_cast<void*>(static_cast<intptr_t>(v));
+    else
+        return reinterpret_cast<void*>(static_cast<uintptr_t>(v));
 }
 
 template <typename T>
-inline std::enable_if_t<std::is_integral_v<T> && std::is_signed_v<T>, T>
-gjs_pointer_to_int(void* p) {
-    return static_cast<T>(reinterpret_cast<intptr_t>(p));
-}
+constexpr T gjs_pointer_to_int(void* p) {
+    static_assert(std::is_integral_v<T>, "Need integer value");
 
-template <typename T>
-inline std::enable_if_t<std::is_integral_v<T> && std::is_unsigned_v<T>, T>
-gjs_pointer_to_int(void* p) {
-    return static_cast<T>(reinterpret_cast<uintptr_t>(p));
+    if constexpr (std::is_signed_v<T>)
+        return static_cast<T>(reinterpret_cast<intptr_t>(p));
+    else
+        return static_cast<T>(reinterpret_cast<uintptr_t>(p));
 }
 
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