Try non-array approach

EricCousineau-TRI · Nov 30, 2018 · 2d2c142 · 2d2c142
1 parent 414f65c
commit 2d2c142
Showing 1 changed file with 13 additions and 13 deletions.
diff --git a/include/pybind11/numpy.h b/include/pybind11/numpy.h
@@ -114,11 +114,11 @@ template <typename T> struct same_size {
 };
 
 // Lookup a type according to its size, and return a value corresponding to the NumPy typenum.
-template <typename Concrete, typename... Check>
-constexpr int platform_lookup(const std::array<int, sizeof...(Check)> codes) {
-    using code_index = std::integral_constant<int, constexpr_first<same_size<Concrete>::template as, Check...>()>;
-    static_assert(code_index::value != sizeof...(Check), "Unable to match type on this platform");
-    return codes[code_index::value];
+template <typename Concrete, typename... Check, typename... Int>
+constexpr int platform_lookup(Int... codes) {
+    constexpr int code_index = constexpr_first<same_size<Concrete>::template as, Check...>();
+    static_assert(code_index != sizeof...(Check), "Unable to match type on this platform");
+    return std::get<code_index>(std::make_tuple(codes...));
 }
 
 struct npy_api {
@@ -148,14 +148,14 @@ struct npy_api {
         // `npy_common.h` defines the integer aliases. In order, it checks:
         // NPY_BITSOF_LONG, NPY_BITSOF_LONGLONG, NPY_BITSOF_INT, NPY_BITSOF_SHORT, NPY_BITSOF_CHAR
         // and assigns the alias to the first matching size, so we should check in this order.
-        NPY_INT32_ = platform_lookup<std::int32_t, long, int, short>({{
-            NPY_LONG_, NPY_INT_, NPY_SHORT_}}),
-        NPY_UINT32_ = platform_lookup<std::uint32_t, unsigned long, unsigned int, unsigned short>({{
-            NPY_ULONG_, NPY_UINT_, NPY_USHORT_}}),
-        NPY_INT64_ = platform_lookup<std::int64_t, long, long long, int>({{
-            NPY_LONG_, NPY_LONGLONG_, NPY_INT_}}),
-        NPY_UINT64_ = platform_lookup<std::uint64_t, unsigned long, unsigned long long, unsigned int>({{
-            NPY_ULONG_, NPY_ULONGLONG_, NPY_UINT_}}),
+        NPY_INT32_ = platform_lookup<std::int32_t, long, int, short>(
+            NPY_LONG_, NPY_INT_, NPY_SHORT_),
+        NPY_UINT32_ = platform_lookup<std::uint32_t, unsigned long, unsigned int, unsigned short>(
+            NPY_ULONG_, NPY_UINT_, NPY_USHORT_),
+        NPY_INT64_ = platform_lookup<std::int64_t, long, long long, int>(
+            NPY_LONG_, NPY_LONGLONG_, NPY_INT_),
+        NPY_UINT64_ = platform_lookup<std::uint64_t, unsigned long, unsigned long long, unsigned int>(
+            NPY_ULONG_, NPY_ULONGLONG_, NPY_UINT_),
     };
 
     typedef struct {