--- a/Core/Toolbox.cpp	Wed Jun 22 15:31:07 2016 +0200
+++ b/Core/Toolbox.cpp	Thu Jun 23 10:08:27 2016 +0200
@@ -1506,4 +1506,63 @@
 
     return fopen(path.c_str(), m);
   }
+
+  
+
+  static bool IsUnreservedCharacter(char c)
+  {
+    // This function checks whether "c" is an unserved character
+    // wrt. an URI percent-encoding
+    // https://en.wikipedia.org/wiki/Percent-encoding#Percent-encoding%5Fin%5Fa%5FURI
+
+    return ((c >= 'A' && c <= 'Z') ||
+            (c >= 'a' && c <= 'z') ||
+            (c >= '0' && c <= '9') ||
+            c == '-' ||
+            c == '_' ||
+            c == '.' ||
+            c == '~');
+  }
+
+  void Toolbox::UriEncode(std::string& target,
+                          const std::string& source)
+  {
+    // Estimate the length of the percent-encoded URI
+    size_t length = 0;
+
+    for (size_t i = 0; i < source.size(); i++)
+    {
+      if (IsUnreservedCharacter(source[i]))
+      {
+        length += 1;
+      }
+      else
+      {
+        // This character must be percent-encoded
+        length += 3;
+      }
+    }
+
+    target.clear();
+    target.reserve(length);
+
+    for (size_t i = 0; i < source.size(); i++)
+    {
+      if (IsUnreservedCharacter(source[i]))
+      {
+        target.push_back(source[i]);
+      }
+      else
+      {
+        // This character must be percent-encoded
+        uint8_t byte = static_cast<uint8_t>(source[i]);
+        uint8_t a = byte >> 4;
+        uint8_t b = byte & 0x0f;
+
+        target.push_back('%');
+        target.push_back(a < 10 ? a + '0' : a - 10 + 'A');
+        target.push_back(b < 10 ? b + '0' : b - 10 + 'A');
+      }
+    }
+  }  
 }

--- a/Core/Toolbox.h	Wed Jun 22 15:31:07 2016 +0200
+++ b/Core/Toolbox.h	Thu Jun 23 10:08:27 2016 +0200
@@ -199,5 +199,8 @@
 
     FILE* OpenFile(const std::string& path,
                    FileMode mode);
+
+    void UriEncode(std::string& target,
+                   const std::string& source);
   }
 }

--- a/UnitTestsSources/UnitTestsMain.cpp	Wed Jun 22 15:31:07 2016 +0200
+++ b/UnitTestsSources/UnitTestsMain.cpp	Thu Jun 23 10:08:27 2016 +0200
@@ -926,6 +926,25 @@
 }
 
 
+TEST(Toolbox, UriEncode)
+{
+  std::string s;
+
+  // Unreserved characters must not be modified
+  std::string t = "aAzZ09.-~_";
+  Toolbox::UriEncode(s, t); 
+  ASSERT_EQ(t, s);
+
+  Toolbox::UriEncode(s, "!#$&'()*+,/:;=?@[]"); ASSERT_EQ("%21%23%24%26%27%28%29%2A%2B%2C%2F%3A%3B%3D%3F%40%5B%5D", s);  
+  Toolbox::UriEncode(s, "%"); ASSERT_EQ("%25", s);
+
+  // Encode characters from UTF-8. This is the test string from the
+  // file "../Resources/EncodingTests.py"
+  Toolbox::UriEncode(s, "\x54\x65\x73\x74\xc3\xa9\xc3\xa4\xc3\xb6\xc3\xb2\xd0\x94\xce\x98\xc4\x9d\xd7\x93\xd8\xb5\xc4\xb7\xd1\x9b\xe0\xb9\x9b\xef\xbe\x88\xc4\xb0"); 
+  ASSERT_EQ("Test%C3%A9%C3%A4%C3%B6%C3%B2%D0%94%CE%98%C4%9D%D7%93%D8%B5%C4%B7%D1%9B%E0%B9%9B%EF%BE%88%C4%B0", s);
+}
+
+
 int main(int argc, char **argv)
 {
   Logging::Initialize();