Use nonstd::to_lower

src/ds/nonstd.h

@@ -2,6 +2,7 @@
 // Licensed under the Apache 2.0 License.
 #pragma once
 
+#include <algorithm>
 #include <array>
 #include <cctype>
 #include <string>
@@ -61,14 +62,14 @@ namespace nonstd
 
   /** converts strings to upper or lower case, in-place
    */
-  void to_upper(std::string& s)
+  static void to_upper(std::string& s)
   {
     std::transform(s.begin(), s.end(), s.begin(), [](unsigned char c) {
       return std::toupper(c);
     });
   }
 
-  void to_lower(std::string& s)
+  static void to_lower(std::string& s)
   {
     std::transform(s.begin(), s.end(), s.begin(), [](unsigned char c) {
       return std::tolower(c);

src/http/http_builder.h

@@ -59,9 +59,7 @@ namespace http
     void set_header(std::string k, const std::string& v)
     {
       // Store all headers lower-cased to simplify case-insensitive lookup
-      std::transform(k.begin(), k.end(), k.begin(), [](unsigned char c) {
-        return std::tolower(c);
-      });
+      nonstd::to_lower(k);
       headers[k] = v;
     }
 

src/http/http_parser.h

@@ -277,9 +277,7 @@ namespace http
       // HTTP headers are stored lowercase as it is easier to verify HTTP
       // signatures later on
       auto f = std::string(at, length);
-      std::transform(f.begin(), f.end(), f.begin(), [](unsigned char c) {
-        return std::tolower(c);
-      });
+      nonstd::to_lower(f);
       partial_parsed_header.first.append(f);
     }
 

src/http/http_sig.h

@@ -33,10 +33,7 @@ namespace http
       if (f == auth::SIGN_HEADER_REQUEST_TARGET)
       {
         // Store verb as lowercase
-        std::transform(
-          verb.begin(), verb.end(), verb.begin(), [](unsigned char c) {
-            return std::tolower(c);
-          });
+        nonstd::to_lower(verb);
         value = fmt::format("{} {}", verb, path);
         if (!query.empty())
         {

src/http/test/http_test.cpp

@@ -22,9 +22,7 @@ std::vector<uint8_t> s_to_v(char const* s)
 
 std::string to_lowercase(std::string s)
 {
-  std::transform(s.begin(), s.end(), s.begin(), [](unsigned char c) {
-    return std::tolower(c);
-  });
+  nonstd::to_lower(s);
   return s;
 }
 

src/node/rpc/common_endpoint_registry.h

@@ -248,11 +248,7 @@ namespace ccf
         for (auto& [verb, endpoint] : it->second)
         {
           std::string verb_name = http_method_str(verb);
-          std::transform(
-            verb_name.begin(),
-            verb_name.end(),
-            verb_name.begin(),
-            [](unsigned char c) { return std::tolower(c); });
+          nonstd::to_lower(verb_name);
           j[verb_name] =
             GetSchema::Out{endpoint.params_schema, endpoint.result_schema};
         }