diff --git a/include/mcc/mcc_deserializer.h b/include/mcc/mcc_deserializer.h
index afae187..41bf678 100644
--- a/include/mcc/mcc_deserializer.h
+++ b/include/mcc/mcc_deserializer.h
@@ -132,14 +132,17 @@ protected:
 
         auto it = r.begin();
         for (auto const& el : r_str) {
-            auto err = dsr(el, val, std::forward<DeserParamsT>(params)...);
+            // auto err = dsr(el, val, std::forward<DeserParamsT>(params)...);
+            auto err = dsr(el, val, params);
             if (err) {
                 return mcc_deduced_err(err, MccDeserializerErrorCode::ERROR_UNDERLYING_DESERIALIZER);
             }
 
             if (it == r.end()) {
-                std::back_inserter(r) = val;
-                it = r.end();
+                if constexpr (!traits::mcc_fixed_size_range<R>) {
+                    std::back_inserter(r) = val;
+                    it = r.end();
+                }
             } else {
                 *it = val;
                 ++it;
diff --git a/include/mcc/mcc_epoch.h b/include/mcc/mcc_epoch.h
index a71ebae..e98f17f 100644
--- a/include/mcc/mcc_epoch.h
+++ b/include/mcc/mcc_epoch.h
@@ -62,6 +62,26 @@ public:
         fromTimePoint(std::forward<decltype(other)>(other).UTC());
     }
 
+    MccCelestialCoordEpoch(traits::mcc_input_char_range auto&& str)
+    {
+        // ignore possible errors!!!
+        fromCharRange(std::forward<decltype(str)>(str));
+    }
+
+    template <typename ClockT, typename DurT>
+    MccCelestialCoordEpoch(std::chrono::time_point<ClockT, DurT> const& tp) : MccCelestialCoordEpoch()
+    {
+        fromTimePoint(tp);
+    }
+
+    template <typename VT>
+    MccCelestialCoordEpoch(VT&& mjd)
+        requires std::is_arithmetic_v<std::remove_cvref_t<VT>>
+    {
+        // ignore possible errors!!!
+        fromMJD(std::forward<decltype(mjd)>(mjd));
+    }
+
     MccCelestialCoordEpoch& operator=(mcc_coord_epoch_c auto&& other)
     {
         fromTimePoint(std::forward<decltype(other)>(other).UTC());
@@ -89,7 +109,7 @@ public:
 
     template <typename VT>
     MccCelestialCoordEpoch& operator=(VT&& mjd)
-        requires std::is_arithmetic_v<VT>
+        requires std::is_arithmetic_v<std::remove_cvref_t<VT>>
     {
         // ignore possible errors!!!
         auto ok = fromMJD(std::forward<decltype(mjd)>(mjd));
diff --git a/include/mcc/mcc_keyvalue.h b/include/mcc/mcc_keyvalue.h
index c5a5f38..ca84f12 100644
--- a/include/mcc/mcc_keyvalue.h
+++ b/include/mcc/mcc_keyvalue.h
@@ -176,36 +176,54 @@ public:
     template <typename T>
     std::expected<T, std::error_code> getValue(std::string_view key) const
     {
-        // T v;
-        // auto err = forKey(key, [&v](auto const& rec) -> std::error_code {
-        //     using VT = decltype(rec.value);
-        //     if constexpr (std::convertible_to<VT, T>) {
-        //         v = rec.value;
-        //     } else if constexpr (std::constructible_from<T, VT>) {
-        //         v = T(rec.value);
-        //     } else {
-        //         return MccKeyValueHolderErrorCode::ERROR_INCOMPATIBLE_TYPE;
-        //     }
-
-        //     return MccKeyValueHolderErrorCode::ERROR_OK;
-        // });
-
-        // if (err) {
-        //     return std::unexpected(err);
-        // } else {
-        //     return v;
-        // }
-
-        return forHash1(utils::FNV1aHash(key), [](auto const& rec) {
+        // ugly, but works for non-default constructible values
+        alignas(T) unsigned char buff[sizeof(T)];
+        auto err = forKey(key, [&buff](auto const& rec) -> std::error_code {
             using VT = decltype(rec.value);
             if constexpr (std::constructible_from<T, VT>) {
-                return T{rec.value};
+                new (buff) T(rec.value);
             } else {
-                return std::unexpected(MccKeyValueHolderErrorCode::ERROR_INCOMPATIBLE_TYPE);
+                return MccKeyValueHolderErrorCode::ERROR_INCOMPATIBLE_TYPE;
             }
+
+            return MccKeyValueHolderErrorCode::ERROR_OK;
         });
+
+        if (err) {
+            return std::unexpected(err);
+        } else {
+            auto ptr = reinterpret_cast<T*>(&buff[0]);
+            auto v = std::move(*ptr);
+            ptr->~T();  // one needs explicitly call destructor here to avvoid side effects!!!
+
+            return v;
+        }
     }
 
+    // template <typename T>
+    // std::expected<T, std::error_code> getValue(std::string_view key) const
+    // {
+    //     T v;
+    //     auto err = forKey(key, [&v](auto const& rec) -> std::error_code {
+    //         using VT = decltype(rec.value);
+    //         if constexpr (std::convertible_to<VT, T>) {
+    //             v = rec.value;
+    //         } else if constexpr (std::constructible_from<T, VT>) {
+    //             v = T(rec.value);
+    //         } else {
+    //             return MccKeyValueHolderErrorCode::ERROR_INCOMPATIBLE_TYPE;
+    //         }
+
+    //         return MccKeyValueHolderErrorCode::ERROR_OK;
+    //     });
+
+    //     if (err) {
+    //         return std::unexpected(err);
+    //     } else {
+    //         return v;
+    //     }
+    // }
+
     template <std::ranges::contiguous_range R, typename T>
     std::error_code setValue(R const& key, const T& value)
     {
@@ -219,10 +237,40 @@ public:
 
         auto ec = forHash(hash, [&value](auto& rec) -> std::error_code {
             using VT = decltype(rec.value);
-            if constexpr (std::assignable_from<VT&, T>) {
+            if constexpr (requires { rec.value = value; }) {
                 rec.value = value;
             } else if constexpr (std::constructible_from<VT, T>) {
                 rec.value = VT(value);
+            } else if constexpr (std::ranges::range<VT> && std::ranges::range<T> &&
+                                 requires(std::ranges::range_value_t<VT> v, std::ranges::range_value_t<T> t) {
+                                     v = t;
+                                 }) {
+                const auto& val = std::is_pointer_v<std::decay_t<T>> ? std::span{value} : value;
+
+                size_t N = std::ranges::distance(rec.value.begin(), rec.value.end());
+                size_t M = std::ranges::distance(val.begin(), val.end());
+
+                auto it = std::ranges::begin(rec.value);
+                std::ranges::for_each_n(val.begin(), N > M ? M : N, [&it](auto const& el) {
+                    *it = el;
+                    ++it;
+                });
+
+                if (N >= M) {  // resize to match the size of the input range
+                    if constexpr (!traits::mcc_non_resizable_range<VT>) {
+                        rec.value.resize(M);
+                    }
+                } else {  // append if allowed
+                    if constexpr (!traits::mcc_fixed_size_range<VT>) {
+                        std::ranges::for_each_n(val.begin(), N, [&it](auto const& el) {
+                            *it = el;
+                            ++it;
+                        });
+
+                        std::ranges::for_each(val | std::views::drop(N),
+                                              [&rec](auto const& el) { std::back_inserter(rec.value) = el; });
+                    }
+                }
             } else {
                 return MccKeyValueHolderErrorCode::ERROR_INCOMPATIBLE_TYPE;
             }
@@ -450,67 +498,6 @@ protected:
         return MccKeyValueHolderErrorCode::ERROR_INVALID_KEY;
     }
 
-    template <typename FuncT>
-    auto forHash1(this auto&& self, size_t hash, FuncT&& func)
-    {
-        return std::forward<decltype(self)>(self).template forHash1Impl<NUMBER_OF_RECORDS / 2>(
-            hash, std::forward<FuncT>(func), 0, NUMBER_OF_RECORDS - 1);
-    }
-
-    //
-    // implements a binary search
-    //
-    template <size_t I = NUMBER_OF_RECORDS / 2, typename FuncT>
-    auto forHash1Impl(this auto&& self,
-                      size_t hash,
-                      FuncT&& func,
-                      size_t start = 0,
-                      size_t stop = NUMBER_OF_RECORDS - 1)
-    {
-        using func_t = std::remove_cvref_t<FuncT>;
-
-        if constexpr (I < NUMBER_OF_RECORDS) {
-            if (hash == std::forward<decltype(self)>(self)._mapHash[I].first) {
-                constexpr auto idx = std::forward<decltype(self)>(self)._mapHash[I].second;
-                using rec_t = std::tuple_element_t<idx, DESCR_T>;
-
-                if constexpr (std::is_void_v<std::invoke_result_t<func_t, rec_t>>) {
-                    std::forward<FuncT>(func)(std::get<idx>(std::forward<decltype(self)>(self)._keyValue));
-                } else {
-                    return std::forward<FuncT>(func)(std::get<idx>(std::forward<decltype(self)>(self)._keyValue));
-                }
-            } else if (hash < std::forward<decltype(self)>(self)._mapHash[I].first) {
-                if (stop - start > 1) {
-                    return std::forward<decltype(self)>(self).template forHash1Impl<I / 2>(
-                        hash, std::forward<FuncT>(func), start, I - 1);
-                }
-
-                const auto idx = self._mapHash[I - 1].second;
-                using rec_t = std::tuple_element_t<idx, DESCR_T>;
-
-                if constexpr (std::is_void_v<std::invoke_result_t<func_t, rec_t>>) {
-                    std::forward<FuncT>(func)(std::get<idx>(std::forward<decltype(self)>(self)._keyValue));
-                } else {
-                    return std::forward<FuncT>(func)(std::get<idx>(std::forward<decltype(self)>(self)._keyValue));
-                }
-            } else {  // hash > std::forward<decltype(self)>(self)._mapHash[I].first
-                if (stop - start > 1) {
-                    return std::forward<decltype(self)>(self).template forHash1Impl<I / 2>(
-                        hash, std::forward<FuncT>(func), I + 1, stop);
-                }
-
-                const auto idx = self._mapHash[I + 1].second;
-                using rec_t = std::tuple_element_t<idx, DESCR_T>;
-
-                if constexpr (std::is_void_v<std::invoke_result_t<func_t, rec_t>>) {
-                    std::forward<FuncT>(func)(std::get<idx>(std::forward<decltype(self)>(self)._keyValue));
-                } else {
-                    return std::forward<FuncT>(func)(std::get<idx>(std::forward<decltype(self)>(self)._keyValue));
-                }
-            }
-        }
-    }
-
     template <size_t I = 0, traits::mcc_output_char_range R, traits::mcc_input_char_range RecDelimT>
     std::error_code formatRecord(R& output_buffer, RecDelimT rec_delim, bool is_default = false)
     {
diff --git a/include/mcc/mcc_traits.h b/include/mcc/mcc_traits.h
index 3f02282..11b2ad5 100644
--- a/include/mcc/mcc_traits.h
+++ b/include/mcc/mcc_traits.h
@@ -56,7 +56,13 @@ template <typename R>
 concept mcc_range_of_output_char_range =
     std::ranges::range<R> && traits::mcc_output_char_range<std::ranges::range_value_t<R>>;
 
+// std::array, std::span(v_t, N), std::tuple
+template <typename R>
+concept mcc_fixed_size_range = std::ranges::range<R> && requires { std::tuple_size<std::remove_cvref_t<R>>::value; };
 
+// non-resizable ranges
+template <typename R>
+concept mcc_non_resizable_range = std::ranges::range<R> && !requires(R r, std::size_t n) { r.resize(n); };
 
 // https://stackoverflow.com/questions/72430369/how-to-check-that-a-type-is-formattable-using-type-traits-concepts)
 template <typename T>
diff --git a/tests/mcc_keyvalue_test.cpp b/tests/mcc_keyvalue_test.cpp
index 063dc1c..33e64b0 100644
--- a/tests/mcc_keyvalue_test.cpp
+++ b/tests/mcc_keyvalue_test.cpp
@@ -4,6 +4,59 @@
 
 using namespace mcc::impl;
 
+
+// example of non-default constructible class
+struct VT {
+    VT(int v) : _v(v) {}
+
+    void set(int v)
+    {
+        _v = v;
+    }
+
+    int v() const
+    {
+        return _v;
+    }
+
+protected:
+    int _v{};
+};
+
+
+template <>
+struct mcc::impl::MccSerializer<VT> : MccSerializerBase {
+    static constexpr std::string_view serializerName{"MCC-VT-SERIALIZER"};
+
+    template <mcc_serialization_params_c ParamsT = mcc_serialization_params_t>
+    error_t operator()(traits::mcc_output_char_range auto& output,
+                       VT const& value,
+                       ParamsT const& params = mcc_serialization_params_t{})
+    {
+        return MccSerializer<int>{}(output, value.v(), params);
+    }
+};
+
+template <>
+struct mcc::impl::MccDeserializer<VT> : MccDeserializerBase {
+    static constexpr std::string_view deserializerName{"MCC-VT-DESERIALIZER"};
+
+    template <mcc_serialization_params_c ParamsT = mcc_serialization_params_t>
+    error_t operator()(traits::mcc_input_char_range auto const& input,
+                       VT& value,
+                       ParamsT const& params = mcc_serialization_params_t{})
+    {
+        int v;
+        auto err = MccDeserializer<int>{}(input, v, params);
+        if (!err) {
+            value.set(v);
+        }
+
+        return err;
+    }
+};
+
+
 static auto kv_desc = std::make_tuple(
     mcc_simple_kv_record_t{"bb", MccAngle{11.5_degs}, MccAngle{11.5_degs}, mcc_serialization_params_t{}},
     mcc_simple_kv_record_t{"aaa", std::string("AAA"), std::string("AAA"), mcc_serialization_params_t{}},
@@ -12,7 +65,9 @@ static auto kv_desc = std::make_tuple(
         "ddd", MccAngle{11.5_degs}, MccAngle{11.5_degs},
         mcc_serialization_params_t{.angle_format = mcc::MccSerializedAngleFormat::MCC_SERIALIZED_FORMAT_SXGM_HOURS}},
     mcc_make_simple_kv_record("eee", 1.5),
-    mcc_make_simple_kv_record("arr", std::vector<int>{1, 2, 3, 4, 5, 6, 7}));
+    mcc_make_simple_kv_record("arr", std::vector<int>{1, 2, 3, 4, 5, 6, 7}),
+    mcc_make_simple_kv_record("vt", VT(77)),
+    mcc_make_simple_kv_record("sarr", std::array<double, 3>{1, 2, 3}));
 
 
 
@@ -88,6 +143,18 @@ int main()
         // return 1;
     }
 
+    err = kv.setValue("arr", std::array{10, 20, 30});
+    if (err) {
+        std::println("ERR = {}", err);
+        // return 1;
+    }
+
+    err = kv.setValue("sarr", std::vector{10, 20, 30, 40, 50});
+    if (err) {
+        std::println("ERR = {}", err);
+        // return 1;
+    }
+
     std::println("------------------------------------");