Perform LowerCase & UpperCase transformations in-place

- Refactored to share implementation and reduce code duplication.

Author: eduar-hte

src/actions/transformations/lower_case.cc

@@ -16,7 +16,7 @@
 
 #include "lower_case.h"
 
-#include <locale>
+#include <cctype>
 
 
 namespace modsecurity::actions::transformations {
@@ -26,17 +26,9 @@ LowerCase::LowerCase(const std::string &a)
     : Transformation(a) {
 }
 
-bool LowerCase::transform(std::string &val, const Transaction *trans) const {
-    std::locale loc;
-    std::string value(val);
-
-    for (std::string::size_type i=0; i < value.length(); ++i) {
-        value[i] = std::tolower(value[i], loc);
-    }
-
-    const auto changed = val != value;
-    val = value;
-    return changed;
+bool LowerCase::transform(std::string &value, const Transaction *trans) const {
+    return convert(value, [](auto c) {
+                    return std::tolower(c); });
 }
 
 

src/actions/transformations/lower_case.h

@@ -18,13 +18,28 @@
 
 #include "transformation.h"
 
+#include <algorithm>
+
 namespace modsecurity::actions::transformations {
 
 class LowerCase : public Transformation {
  public:
     explicit LowerCase(const std::string &action);
 
     bool transform(std::string &value, const Transaction *trans) const override;
+
+    template<typename Operation>
+    static bool convert(std::string &val, Operation op) {
+        bool changed = false;
+
+        std::transform(val.begin(), val.end(), val.data(),
+                       [&](auto c) { 
+                            const auto nc = op(c);
+                            if(nc != c) changed = true; 
+                            return nc; });
+
+        return changed;
+    }
 };
 
 }  // namespace modsecurity::actions::transformations

src/actions/transformations/upper_case.cc

@@ -16,7 +16,10 @@
 
 #include "upper_case.h"
 
-#include <locale>
+#include <cctype>
+
+#include "lower_case.h"
+
 
 namespace modsecurity::actions::transformations {
 
@@ -25,17 +28,9 @@ UpperCase::UpperCase(const std::string &a)
     : Transformation(a) {
 }
 
-bool UpperCase::transform(std::string &val, const Transaction *trans) const {
-    std::string value(val);
-    std::locale loc;
-
-    for (std::string::size_type i=0; i < value.length(); ++i) {
-        value[i] = std::toupper(value[i], loc);
-    }
-
-    const auto changed = val != value;
-    val = value;
-    return changed;
+bool UpperCase::transform(std::string &value, const Transaction *trans) const {
+    return LowerCase::convert(value, [](auto c)
+                              { return std::toupper(c); });
 }