test clear()

str-to-num.hpp

@@ -210,21 +210,22 @@ class s2n_basic {
   TOut m_data{};
 
 public:
-  // use a container since TConverter::to_str() will return an array
+  // container for the decrypted/restored string
+  // using a container since TConverter::to_str() will return an array
   struct str_container {
     constexpr static s2n_sz_t count = str_count;
     TChar data[str_count + 1]{};
 
     constexpr void clear() {
       for (s2n_sz_t idx = 0; idx < str_count; ++idx) {
         // data[idx] = TChar(); // easy to detect
-        data[idx] += str_count ^ (idx + 1);
-        data[idx] *= idx + 2;
+        data[idx] += str_count ^ (idx + 3);
+        data[idx] *= idx + 3;
         data[idx] ^= idx + 3;
       }
 
-      data[str_count] = str_count * (data[0] + 1);
-      data[str_count] ^= (data[0] - 1);
+      data[str_count] = str_count * (data[0] + 3);
+      data[str_count] ^= (data[0] - 3);
     }
 
     // constant destruction is available since C++20: https://en.cppreference.com/w/cpp/language/constexpr
@@ -282,15 +283,15 @@ namespace s2n_cvt {
     constexpr static void to_num(TChar (&dst) [StrCount], const TStr& src) noexcept {
       for (s2n_sz_t src_idx = 0; src_idx < StrCount; ++src_idx) {
         const auto key2 = (StrCount << (src_idx + 3)) | (src_idx + 3);
-        dst[src_idx] = src[src_idx] ^ static_cast<TChar>(VKey ^ src_idx) ^ static_cast<TChar>(key2);
+        dst[src_idx] = static_cast<TChar>(src[src_idx] ^ VKey ^ (src_idx + 12) ^ key2);
       }
     }
 
     template<typename TStr, s2n_sz_t StrCount, typename TChar>
     constexpr static void to_str(TChar (&dst) [StrCount + 1], const TChar (&src) [StrCount]) noexcept {
       for (s2n_sz_t src_idx = 0; src_idx < StrCount; ++src_idx) {
         const auto key2 = (StrCount << (src_idx + 3)) | (src_idx + 3);
-        dst[src_idx] = src[src_idx] ^ static_cast<TChar>(VKey ^ src_idx) ^ static_cast<TChar>(key2);
+        dst[src_idx] = static_cast<TChar>(src[src_idx] ^ VKey ^ (src_idx + 12) ^ key2);
       }
     }
   };

test/test.cpp

@@ -89,6 +89,21 @@ int main()
     std::cout << std::hex << "FNV 1a = 0x" << smsm33.data() << std::endl;
   }
 
+  {
+    constexpr auto clear_me_after_use = s2n("my super secret");
+
+    {
+      constexpr auto actual_str_constexpr = clear_me_after_use.str();
+      static_assert(same_str_data(actual_str_constexpr.data, "my super secret"), "error");
+    }
+
+    auto actual_str = clear_me_after_use.str();
+    std::cout << std::hex << "actual str = [" << actual_str.data << "]" << std::endl;
+    actual_str.clear(); // CANNOT BE RECOVERED
+    // invalid use, we have to call .str() again to get a new instance
+    // std::cout << std::hex << "actual str = [" << actual_str.data << "]" << std::endl;
+  }
+
 
   using tt1 = str_char_t<char (&) [4]>;
   using tt2 = str_char_t<const char (&) [4]>;