Added SafeCastToEnum

commit_hash:44102d9b2c000eefdfd91997a40a055b29d647c7

6 files changed, 139 insertions, 0 deletions

diff --git a/util/generic/enum_cast.cpp b/util/generic/enum_cast.cpp
new file mode 100644
index 00000000000..8db625ef440
--- /dev/null
+++ b/util/generic/enum_cast.cpp
@@ -0,0 +1,12 @@
+#include "enum_cast.h"
+
+#include <util/generic/yexception.h>
+#include <util/system/type_name.h>
+
+namespace NPrivate {
+
+    [[noreturn]] void OnSafeCastToEnumUnexpectedValue(const std::type_info& valueTypeInfo) {
+        ythrow TBadCastException() << "Unexpected enum " << TypeName(valueTypeInfo) << " value";
+    }
+
+} // namespace NPrivate
diff --git a/util/generic/enum_cast.h b/util/generic/enum_cast.h
new file mode 100644
index 00000000000..59dee47e889
--- /dev/null
+++ b/util/generic/enum_cast.h
@@ -0,0 +1,46 @@
+#pragma once
+
+#include <util/generic/cast.h>
+#include <util/generic/serialized_enum.h>
+
+#include <optional>
+#include <type_traits>
+#include <typeinfo>
+
+namespace NPrivate {
+
+    [[noreturn]] void OnSafeCastToEnumUnexpectedValue(const std::type_info& valueTypeInfo);
+
+} // namespace NPrivate
+
+/**
+ * Safely cast an integer value to the enum value.
+ * @throw yexception is case of unknown enum underlying type value
+ *
+ * @tparam TEnum     enum type
+ */
+template <typename TEnum, typename TInteger, typename = std::enable_if_t<std::is_enum_v<TEnum>>>
+TEnum SafeCastToEnum(TInteger integerValue) {
+    using TUnderlyingEnumType = std::underlying_type_t<TEnum>;
+
+    std::optional<TUnderlyingEnumType> value;
+    try {
+        value = SafeIntegerCast<TUnderlyingEnumType>(integerValue);
+    } catch (const TBadCastException&) {
+        // SafeIntegerCast throws TBadCastException when TInteger cannot be cast
+        // to TUnderlyingEnumType but the exception message is about integer
+        // value cast being unsafe.
+        // SafeCastToEnum must throw TBadCastException with its own exception
+        // message even if integer cast fails.
+    }
+
+    if (value.has_value()) {
+        for (TEnum enumValue : GetEnumAllValues<TEnum>()) {
+            if (static_cast<TUnderlyingEnumType>(enumValue) == *value) {
+                return enumValue;
+            }
+        }
+    }
+
+    NPrivate::OnSafeCastToEnumUnexpectedValue(typeid(TEnum));
+}
diff --git a/util/generic/enum_cast_ut.cpp b/util/generic/enum_cast_ut.cpp
new file mode 100644
index 00000000000..0b96235bcaf
--- /dev/null
+++ b/util/generic/enum_cast_ut.cpp
@@ -0,0 +1,49 @@
+#include "enum_cast.h"
+
+#include "enum_cast_ut.h"
+
+#include <library/cpp/testing/unittest/registar.h>
+
+Y_UNIT_TEST_SUITE(TestEnumCast) {
+    Y_UNIT_TEST(SafeCastToEnumTest) {
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EIntEnum>(0), EIntEnum::Zero);
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EIntEnum>(1), EIntEnum::One);
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EIntEnum>(2), EIntEnum::Two);
+        UNIT_ASSERT_EXCEPTION(SafeCastToEnum<EIntEnum>(3), TBadCastException);
+
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EUcharEnum>(0), EUcharEnum::Zero);
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EUcharEnum>(1), EUcharEnum::One);
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EUcharEnum>(2), EUcharEnum::Two);
+        UNIT_ASSERT_EXCEPTION_CONTAINS(
+            SafeCastToEnum<EUcharEnum>(3), TBadCastException,
+            "Unexpected enum");
+        int val1 = 256;
+        UNIT_ASSERT_EXCEPTION_CONTAINS(
+            SafeCastToEnum<EUcharEnum>(val1), TBadCastException,
+            "Unexpected enum");
+        int val2 = -1;
+        UNIT_ASSERT_EXCEPTION_CONTAINS(
+            SafeCastToEnum<EUcharEnum>(val2), TBadCastException,
+            "Unexpected enum");
+        int val3 = 2;
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EUcharEnum>(val3), EUcharEnum::Two);
+
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EBoolEnum>(false), EBoolEnum::False);
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EBoolEnum>(true), EBoolEnum::True);
+
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<EUnscopedIntEnum>(2), UIE_TWO);
+        UNIT_ASSERT_EXCEPTION_CONTAINS(
+            SafeCastToEnum<EUnscopedIntEnum>(3), TBadCastException,
+            "Unexpected enum");
+        UNIT_ASSERT_EXCEPTION_CONTAINS(
+            SafeCastToEnum<EUnscopedIntEnum>(9), TBadCastException,
+            "Unexpected enum");
+
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<ECharEnum>(static_cast<unsigned int>(0)), ECharEnum::Zero);
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<ECharEnum>(static_cast<short>(-1)), ECharEnum::MinusOne);
+        UNIT_ASSERT_VALUES_EQUAL(SafeCastToEnum<ECharEnum>(static_cast<int>(-2)), ECharEnum::MinusTwo);
+        UNIT_ASSERT_EXCEPTION_CONTAINS(
+            SafeCastToEnum<ECharEnum>(static_cast<int>(2)), TBadCastException,
+            "Unexpected enum");
+    }
+} // Y_UNIT_TEST_SUITE(TestEnumCast)
diff --git a/util/generic/enum_cast_ut.h b/util/generic/enum_cast_ut.h
new file mode 100644
index 00000000000..c0fb52864aa
--- /dev/null
+++ b/util/generic/enum_cast_ut.h
@@ -0,0 +1,28 @@
+#pragma once
+
+enum class EIntEnum: int {
+    Zero = 0,
+    One = 1,
+    Two = 2
+};
+
+enum class EUcharEnum: unsigned char {
+    Zero = 0,
+    One = 1,
+    Two = 2
+};
+
+enum class ECharEnum: signed char {
+    Zero = 0,
+    MinusOne = -1,
+    MinusTwo = -2
+};
+
+enum class EBoolEnum: bool {
+    False = false,
+    True = true
+};
+
+enum EUnscopedIntEnum {
+    UIE_TWO = 2,
+};
diff --git a/util/generic/ut/ya.make b/util/generic/ut/ya.make
index 6a605564fec..543b30278cd 100644
--- a/util/generic/ut/ya.make
+++ b/util/generic/ut/ya.make
@@ -12,6 +12,7 @@ SRCS(
     generic/buffer_ut.cpp
     generic/cast_ut.cpp
     generic/deque_ut.cpp
+    generic/enum_cast_ut.cpp
     generic/explicit_type_ut.cpp
     generic/flags_ut.cpp
     generic/function_ref_ut.cpp
@@ -63,4 +64,6 @@ PEERDIR(
     library/cpp/containers/absl_flat_hash
 )
 
+GENERATE_ENUM_SERIALIZATION(generic/enum_cast_ut.h)
+
 END()
diff --git a/util/ya.make b/util/ya.make
index dea1f1f7219..93bcc964a48 100644
--- a/util/ya.make
+++ b/util/ya.make
@@ -90,6 +90,7 @@ JOIN_SRCS(
     generic/buffer.cpp
     generic/cast.cpp
     generic/deque.cpp
+    generic/enum_cast.cpp
     generic/explicit_type.cpp
     generic/fastqueue.cpp
     generic/flags.cpp