add string util case

Author: xiao.dong

src/iceberg/file_format.h

@@ -55,9 +55,9 @@ ICEBERG_EXPORT inline std::string_view ToString(FileFormatType format_type) {
 }
 
 /// \brief Convert a string to a FileFormatType
-ICEBERG_EXPORT constexpr Result<FileFormatType> FileFormatTypeFromString(
+ICEBERG_EXPORT Result<FileFormatType> FileFormatTypeFromString(
     std::string_view str) noexcept {
-  auto lower = internal::StringUtils::to_lower(str);
+  auto lower = internal::StringUtils::ToLower(str);
   if (lower == "parquet") return FileFormatType::kParquet;
   if (lower == "avro") return FileFormatType::kAvro;
   if (lower == "orc") return FileFormatType::kOrc;

src/iceberg/util/string_utils.h

@@ -20,24 +20,23 @@
 #pragma once
 
 #include <algorithm>
+#include <ranges>
 #include <string>
 
 namespace iceberg::internal {
 
 class StringUtils {
  public:
-  static std::string to_lower(std::string_view str) {
+  static std::string ToLower(std::string_view str) {
     std::string input(str);
-    std::transform(input.begin(), input.end(), input.begin(),
-                   [](char c) { return std::tolower(c); });
-    return input;
+    return input | std::views::transform([](char c) { return std::tolower(c); }) |
+           std::ranges::to<std::string>();
   }
 
-  static std::string to_upper(std::string_view str) {
+  static std::string ToUpper(std::string_view str) {
     std::string input(str);
-    std::transform(input.begin(), input.end(), input.begin(),
-                   [](char c) { return std::toupper(c); });
-    return input;
+    return input | std::views::transform([](char c) { return std::toupper(c); }) |
+           std::ranges::to<std::string>();
   }
 };
 

test/CMakeLists.txt

@@ -66,7 +66,8 @@ target_link_libraries(json_serde_test PRIVATE iceberg_static GTest::gtest_main
 add_test(NAME json_serde_test COMMAND json_serde_test)
 
 add_executable(util_test)
-target_sources(util_test PRIVATE formatter_test.cc config_test.cc visit_type_test.cc)
+target_sources(util_test PRIVATE formatter_test.cc config_test.cc visit_type_test.cc
+                                 string_utils_test.cc)
 target_link_libraries(util_test PRIVATE iceberg_static GTest::gtest_main GTest::gmock)
 add_test(NAME util_test COMMAND util_test)
 

test/string_utils_test.cc

@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "iceberg/util/string_utils.h"
+
+#include <gtest/gtest.h>
+
+namespace iceberg {
+
+TEST(StringUtilsTest, ToLower) {
+  ASSERT_EQ(internal::StringUtils::ToLower("AbC"), "abc");
+  ASSERT_EQ(internal::StringUtils::ToLower("A-bC"), "a-bc");
+  ASSERT_EQ(internal::StringUtils::ToLower("A_bC"), "a_bc");
+  ASSERT_EQ(internal::StringUtils::ToLower(""), "");
+  ASSERT_EQ(internal::StringUtils::ToLower(" "), " ");
+  ASSERT_EQ(internal::StringUtils::ToLower("123"), "123");
+}
+
+TEST(StringUtilsTest, ToUpper) {
+  ASSERT_EQ(internal::StringUtils::ToUpper("abc"), "ABC");
+  ASSERT_EQ(internal::StringUtils::ToUpper("A-bC"), "A-BC");
+  ASSERT_EQ(internal::StringUtils::ToUpper("A_bC"), "A_BC");
+  ASSERT_EQ(internal::StringUtils::ToUpper(""), "");
+  ASSERT_EQ(internal::StringUtils::ToUpper(" "), " ");
+  ASSERT_EQ(internal::StringUtils::ToUpper("123"), "123");
+}
+
+}  // namespace iceberg