Utility helper to extract a value from NSNumber. (#9595)

Summary: .

Reviewed By: bsoyluoglu

Differential Revision: D71752749

Author: shoumikhin

extension/apple/ExecuTorch/Internal/ExecuTorchUtils.h

@@ -11,9 +11,11 @@
 #ifdef __cplusplus
 
 #import <executorch/runtime/core/exec_aten/exec_aten.h>
+#import <executorch/runtime/core/exec_aten/util/scalar_type_util.h>
 
 namespace executorch::extension::utils {
 using namespace aten;
+using namespace runtime;
 
 /**
  * Deduces the scalar type for a given NSNumber based on its type encoding.
@@ -41,6 +43,56 @@ static inline ScalarType deduceScalarType(NSNumber *number) {
   return ScalarType::Undefined;
 }
 
+/**
+ * Converts the value held in the NSNumber to the specified C++ type T.
+ *
+ * @tparam T The target C++ numeric type.
+ * @param number The NSNumber instance to extract the value from.
+ * @return The value converted to type T.
+ */
+template <typename T>
+static inline T extractValue(NSNumber *number) {
+  ET_CHECK_MSG(!(isFloatingType(deduceScalarType(number)) &&
+    isIntegralType(CppTypeToScalarType<T>::value, true)),
+    "Cannot convert floating point to integral type");
+  T value;
+  if constexpr (std::is_same_v<T, uint8_t>) {
+    value = number.unsignedCharValue;
+  } else if constexpr (std::is_same_v<T, int8_t>) {
+    value = number.charValue;
+  } else if constexpr (std::is_same_v<T, int16_t>) {
+    value = number.shortValue;
+  } else if constexpr (std::is_same_v<T, int32_t>) {
+    value = number.intValue;
+  } else if constexpr (std::is_same_v<T, int64_t>) {
+    value = number.longLongValue;
+  } else if constexpr (std::is_same_v<T, float>) {
+    value = number.floatValue;
+  } else if constexpr (std::is_same_v<T, double>) {
+    value = number.doubleValue;
+  } else if constexpr (std::is_same_v<T, BOOL>) {
+    value = number.boolValue;
+  } else if constexpr (std::is_same_v<T, uint16_t>) {
+    value = number.unsignedShortValue;
+  } else if constexpr (std::is_same_v<T, uint32_t>) {
+    value = number.unsignedIntValue;
+  } else if constexpr (std::is_same_v<T, uint64_t>) {
+    value = number.unsignedLongLongValue;
+  } else if constexpr (std::is_same_v<T, NSInteger>) {
+    value = number.integerValue;
+  } else if constexpr (std::is_same_v<T, NSUInteger>) {
+    value = number.unsignedIntegerValue;
+  } else if constexpr (std::is_same_v<T, BFloat16> ||
+                       std::is_same_v<T, Half>) {
+    value = T(number.floatValue);
+  } else {
+    static_assert(sizeof(T) == 0, "Unsupported type");
+  }
+  ET_DCHECK_MSG(std::numeric_limits<T>::lowest() <= value && value <= std::numeric_limits<T>::max(),
+    "Value out of range");
+  return value;
+}
+
 } // namespace executorch::extension::utils
 
 #endif // __cplusplus