From 6c747d58f85d29987011d9519109928c3438fcef Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Sun, 14 Jan 2024 19:48:43 +0100
Subject: a

---
 serialize/packbits.cpp | 27 +++++++++++++++++-
 serialize/packbits.hpp | 77 ++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 92 insertions(+), 12 deletions(-)

diff --git a/serialize/packbits.cpp b/serialize/packbits.cpp
index 6ed898c7..86c6f605 100644
--- a/serialize/packbits.cpp
+++ b/serialize/packbits.cpp
@@ -7,6 +7,8 @@ using namespace floormat::detail_Pack;
 
 namespace {
 
+template<std::unsigned_integral T, size_t N> constexpr inline T lowbits = (T{1} << N)-T{1};
+
 template<size_t Val> using us_bits = Bits_<uint16_t, Val>;
 
 static_assert(!Storage<uint32_t, 3>{65535}.check_zero());
@@ -110,7 +112,30 @@ static_assert(std::is_same_v< make_tuple_type<uint8_t, 3>,  std::tuple<uint8_t,
 
 constexpr bool test4()
 {
-    auto t = std::tuple<unsigned, unsigned, unsigned>();
+    using Tuple = std::tuple<uint32_t, uint32_t, uint32_t>;
+    Tuple tuple{};
+    assign_tuple2(tuple, Storage<uint32_t, 32>{(uint32_t)-1}, std::make_index_sequence<3>{},
+                  Bits_<uint32_t, 17>{}, Bits_<uint32_t, 14>{}, Bits_<uint32_t, 1>{});
+    auto [a, b, c] = tuple;
+
+    static_assert(lowbits<uint32_t, 17> != 0);
+    fm_assert(a == lowbits<uint32_t, 17>);
+    fm_assert(b == lowbits<uint32_t, 14>);
+    fm_assert(c & 1);
+
+    //Assign::do_tuple(tuple, Storage<uint32_t, 32>{(uint32_t)-1});
+
+    return true;
+}
+static_assert(test4());
+
+constexpr bool test5()
+{
+    auto st = Storage<uint32_t, 32>{0xB16B00B5};
+    uint32_t a, b, c;
+    using Tuple = std::tuple<uint32_t&, uint32_t&, uint32_t&>;
+    auto t = Tuple{a, b, c};
+    //assign_tuple<uint32_t, std::make_index_sequence<3>, Tuple,
 
     return true;
 }
diff --git a/serialize/packbits.hpp b/serialize/packbits.hpp
index 12c1dd31..527b7676 100644
--- a/serialize/packbits.hpp
+++ b/serialize/packbits.hpp
@@ -5,7 +5,7 @@
 #include "compat/assert.hpp"
 
 namespace floormat::Pack {
-template<std::unsigned_integral T, uint8_t N> struct Bits_;
+template<std::unsigned_integral T, size_t N> struct Bits_;
 } // namespace floormat::Pack
 
 namespace floormat::detail_Pack {
@@ -13,7 +13,7 @@ namespace floormat::detail_Pack {
 using namespace floormat::Pack;
 template<std::unsigned_integral T, size_t Sum, typename... Xs> struct check_size_overflow;
 
-template<std::unsigned_integral T, std::unsigned_integral U, size_t Sum, uint8_t N, typename... Xs>
+template<std::unsigned_integral T, std::unsigned_integral U, size_t Sum, size_t N, typename... Xs>
 struct check_size_overflow<T, Sum, Bits_<U, N>, Xs...>
 {
     static_assert(std::is_same_v<T, U>);
@@ -95,25 +95,80 @@ struct make_tuple_type_
 };
 template<std::unsigned_integral T, size_t N> using make_tuple_type = typename make_tuple_type_<T, N>::Seq;
 
-template<typename T, typename Place, size_t Left>
-static void assign_to_tuple(Place&, Storage<T, Left> st, std::index_sequence<>)
+template<typename T, typename Place, size_t Left, size_t I, size_t... Is, size_t Size, typename... Sizes>
+constexpr void assign_tuple2(Place& p, Storage<T, Left> st, std::index_sequence<I, Is...>, Bits_<T, Size>, Sizes... sizes)
 {
-    fm_assert(st.check_zero());
+    using S = Storage<T, Left>;
+    using next_type = typename S::template next<Size>;
+    get<I>(p) = st.template get<Size>();
+    T next_value = st.template advance<Size>();
+    assign_tuple2(p, next_type{next_value}, std::index_sequence<Is...>{}, sizes...);
 }
 
-template<typename T, typename Place, size_t Left, size_t Size, size_t... Sizes>
-static void assign_to_tuple(Place& p, Storage<T, Left> st, std::index_sequence<Size, Sizes...>)
+template<typename T, typename Place, size_t Left>
+constexpr void assign_tuple2(Place&, Storage<T, Left>, std::index_sequence<>)
 {
-    using std::get;
-    get<Size>(p) = st.template get<Size>(st);
-    assign_to_tuple(p, st.template advance<Size>(), std::index_sequence<Sizes...>{});
 }
 
+#if 0
+template<typename T, typename Indexes, typename... Sizes> struct assign_tuple;
+
+template<typename T, size_t Index, size_t... Indexes, size_t Size, typename... Sizes>
+struct assign_tuple<T, std::index_sequence<Index, Indexes...>, Bits_<T, Size>, Sizes...>
+{
+    static_assert(Size <= sizeof(T)*8, "bit count can't be larger than sizeof(T)*8");
+    static_assert(Size > 0, "bit count can't be zero");
+
+    template<typename Place, size_t Left>
+    static constexpr inline void do_tuple(Place& p, Storage<T, Left> st)
+    {
+        static_assert(requires (Place& p) { std::get<0>(p) = T{0}; });
+        static_assert(std::tuple_size_v<Place> >= sizeof...(Indexes) + 1);
+        static_assert(Size <= Left, "not enough bits for element");
+
+        get<Index>(p) = st.template get<Size>(st.value);
+        using Next = typename Storage<T, Left>::template next<Size>;
+        assign_tuple<T, std::index_sequence<Indexes...>, Sizes...>::
+            template do_tuple<Place, Next>(p, Next{st.template advance<Size>()});
+    }
+
+    static constexpr bool is_empty = false;
+};
+
+template<typename T, size_t Index, size_t... Indexes>
+struct assign_tuple<T, std::index_sequence<Index, Indexes...>>
+{
+    static_assert(sizeof(T) == (size_t)-1, "too few lhs elements");
+    static_assert(sizeof(T) != (size_t)-1);
+};
+
+template<typename T, size_t Size, typename... Sizes>
+struct assign_tuple<T, std::index_sequence<>, Bits_<T, Size>, Sizes...>
+{
+    static_assert(sizeof(T) == (size_t)-1, "too few rhs elements");
+    static_assert(sizeof(T) != (size_t)-1);
+};
+
+template<typename T>
+struct assign_tuple<T, std::index_sequence<>>
+{
+    template<typename Place, size_t Left>
+    static constexpr inline void do_tuple(Place&, Storage<T, Left> st)
+    {
+        fm_assert(st.check_zero());
+    }
+
+    static constexpr bool is_empty = true;
+    using type = T;
+};
+
+#endif
+
 } // namespace floormat::detail_Pack
 
 namespace floormat::Pack {
 
-template<std::unsigned_integral T, uint8_t N>
+template<std::unsigned_integral T, size_t N>
 struct Bits_ final
 {
     static_assert(std::is_fundamental_v<T>);
-- 
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