use 'C' locale for alnum check in urlencoder

Author: WZhuo

src/iceberg/util/url_encoder.cc

@@ -19,6 +19,8 @@
 
 #include "iceberg/util/url_encoder.h"
 
+#include <locale>
+
 namespace iceberg {
 
 namespace {
@@ -36,9 +38,10 @@ std::string UrlEncoder::Encode(std::string_view str_to_encode) {
   std::string result;
   result.reserve(str_to_encode.size() * 3 /* Worst case: every char becomes %XX */);
 
-  for (unsigned char c : str_to_encode) {
-    if (std::isalnum(c) || c == '-' || c == '_' || c == '.' || c == '~') {
-      result += static_cast<char>(c);
+  for (char c : str_to_encode) {
+    if (std::isalnum(c, std::locale::classic()) || c == '-' || c == '_' || c == '.' ||
+        c == '~') {
+      result += c;
     } else {
       result += '%';
       result += hex_chars[c >> 4];

src/iceberg/util/url_encoder.h

@@ -23,7 +23,6 @@
 #include <string_view>
 
 #include "iceberg/iceberg_export.h"
-#include "iceberg/result.h"
 
 /// \file iceberg/util/url_encoder.h
 /// \brief URL encoding and decoding.