refactor: Simplify Packer and Unpacker usage by removing unnecessary converting iterator

Author: rwindegger

examples/first_example.cpp

@@ -9,51 +9,15 @@
 #include <map>
 #include <msgpack23/msgpack23.h>
 
-class converting_insert_iterator final {
-public:
-    using difference_type = std::ptrdiff_t;
-
-    constexpr explicit converting_insert_iterator(std::back_insert_iterator<std::vector<unsigned char>> &&iterator) : store_{std::move(iterator)} {}
-
-    constexpr converting_insert_iterator &operator=(const std::byte &value) {
-        store_ = std::to_underlying(value);
-        return *this;
-    }
-
-    constexpr converting_insert_iterator &operator=(std::byte &&value) {
-        store_ = std::to_underlying(value);
-        return *this;
-    }
-
-    [[nodiscard]] constexpr converting_insert_iterator &operator*() {
-        return *this;
-    }
-
-    constexpr converting_insert_iterator &operator++() {
-        return *this;
-    }
-
-    constexpr converting_insert_iterator operator++(int) {
-        return *this;
-    }
-private:
-    std::back_insert_iterator<std::vector<unsigned char>> store_;
-};
-
 int main() {
     std::map<std::string, int> const original {{"apple", 1}, {"banana", 2}};
 
     std::vector<unsigned char> data{};
-    msgpack23::Packer packer { converting_insert_iterator{ std::back_inserter(data) } };
+    msgpack23::Packer packer { std::back_inserter(data) };
     packer(original);
 
     std::map<std::string, int> unpacked;
-    msgpack23::Unpacker unpacker {
-        std::span<std::byte>{
-            reinterpret_cast<std::byte *>(data.data()),
-            data.size()
-        }
-    };
+    msgpack23::Unpacker unpacker { data };
     unpacker(unpacked);
 
     for (auto const& [key, value] : unpacked) {

include/msgpack23/msgpack23.h

@@ -518,7 +518,7 @@ namespace msgpack23 {
         }
 
         [[nodiscard]] bool check_constant(FormatConstants const &value) const {
-            return current() == static_cast<B>(std::to_underlying(value));
+            return static_cast<B>(current()) == static_cast<B>(std::to_underlying(value));
         }
 
         [[nodiscard]] FormatConstants current_constant() const {