From bf0fe591710677b42a3ce910371951fd8b4fd79e Mon Sep 17 00:00:00 2001
From: wjr <1966336874@qq.com>
Date: Thu, 8 Aug 2024 14:37:53 +0800
Subject: [PATCH] update json and uninitialized

---
 include/wjr/container/generic/vector.hpp |   2 +-
 include/wjr/json/detail.hpp              |  21 +-
 include/wjr/json/document.hpp            |  48 --
 include/wjr/json/json.hpp                | 725 +++++++++++++++++++++++
 include/wjr/json/number.hpp              |   6 +-
 include/wjr/memory/uninitialized.hpp     |   9 +-
 6 files changed, 741 insertions(+), 70 deletions(-)
 delete mode 100644 include/wjr/json/document.hpp
 create mode 100644 include/wjr/json/json.hpp

diff --git a/include/wjr/container/generic/vector.hpp b/include/wjr/container/generic/vector.hpp
index c20b2961..b2ab5da6 100644
--- a/include/wjr/container/generic/vector.hpp
+++ b/include/wjr/container/generic/vector.hpp
@@ -501,10 +501,10 @@ class basic_vector {
         typename std::allocator_traits<allocator_type>::template rebind_alloc<value_type>;
     using _Alty_traits = std::allocator_traits<_Alty>;
 
-    using storage_fn_type = container_fn<_Alty>;
     using __get_size_t = decltype(std::declval<storage_type>().size());
     using IteratorTraits = basic_vector_traits<storage_type>;
 
+    using storage_fn_type = container_fn<_Alty>;
     friend class container_fn<_Alty>;
 
     template <typename T>
diff --git a/include/wjr/json/detail.hpp b/include/wjr/json/detail.hpp
index 58bc8dc4..01b98211 100644
--- a/include/wjr/json/detail.hpp
+++ b/include/wjr/json/detail.hpp
@@ -48,39 +48,31 @@ template <typename T>
 using result = expected<T, result_error>;
 
 enum class value_t : uint8_t {
+    null,
+    boolean,
     number_unsigned,
     number_signed,
     number_float,
-    null,
-    boolean,
     string,
     object,
     array,
 };
 
 using number_unsigned_t = integral_constant<value_t, value_t::number_unsigned>;
-inline constexpr number_unsigned_t number_unsigned_v = {};
 
 using number_signed_t = integral_constant<value_t, value_t::number_signed>;
-inline constexpr number_signed_t number_signed_v = {};
 
 using number_float_t = integral_constant<value_t, value_t::number_float>;
-inline constexpr number_float_t number_float_v = {};
 
 using null_t = integral_constant<value_t, value_t::null>;
-inline constexpr null_t null_v = {};
 
 using boolean_t = integral_constant<value_t, value_t::boolean>;
-inline constexpr boolean_t boolean_v = {};
 
 using string_t = integral_constant<value_t, value_t::string>;
-inline constexpr string_t string_v = {};
 
 using object_t = integral_constant<value_t, value_t::object>;
-inline constexpr object_t object_v = {};
 
 using array_t = integral_constant<value_t, value_t::array>;
-inline constexpr array_t array_v = {};
 
 struct basic_value {
     basic_value() = default;
@@ -92,10 +84,10 @@ struct basic_value {
 
     basic_value(null_t) noexcept : m_type(value_t::null) {}
     basic_value(boolean_t, bool f) noexcept : m_boolean(f), m_type(value_t::boolean) {}
-    basic_value(number_signed_t, int64_t value) noexcept
-        : m_number_signed(value), m_type(value_t::number_signed) {}
     basic_value(number_unsigned_t, uint64_t value) noexcept
         : m_number_unsigned(value), m_type(value_t::number_signed) {}
+    basic_value(number_signed_t, int64_t value) noexcept
+        : m_number_signed(value), m_type(value_t::number_signed) {}
     basic_value(number_float_t, double value) noexcept
         : m_number_float(value), m_type(value_t::number_float) {}
     basic_value(string_t, void *ptr) noexcept : m_ptr(ptr), m_type(value_t::string) {}
@@ -103,15 +95,14 @@ struct basic_value {
     basic_value(array_t, void *ptr) noexcept : m_ptr(ptr), m_type(value_t::array) {}
 
     union {
+        bool m_boolean;
         uint64_t m_number_unsigned;
         int64_t m_number_signed;
         double m_number_float;
-        std::nullptr_t m_null;
-        bool m_boolean;
         void *m_ptr;
     };
 
-    value_t m_type;
+    value_t m_type = value_t::null;
 };
 
 } // namespace wjr::json
diff --git a/include/wjr/json/document.hpp b/include/wjr/json/document.hpp
deleted file mode 100644
index 2b124946..00000000
--- a/include/wjr/json/document.hpp
+++ /dev/null
@@ -1,48 +0,0 @@
-#ifndef WJR_JSON_DOCUMENT_HPP__
-#define WJR_JSON_DOCUMENT_HPP__
-
-#include <map>
-
-#include <wjr/json/visitor.hpp>
-
-namespace wjr::json {
-
-template <typename Traits>
-class basic_json;
-
-template <typename Traits>
-struct get_relocate_mode<basic_json<Traits>> {
-    static constexpr relocate_t value = relocate_t::trivial;
-};
-
-template <template <typename Char, typename Traits, typename Alloc> typename String,
-          template <typename Key, typename Ty, typename Pr, typename Alloc>
-          typename Object,
-          template <typename T, typename Alloc> typename Array,
-          template <typename T> typename Allocator>
-struct basic_json_traits {
-private:
-    using json_type = basic_json<basic_json_traits>;
-
-public:
-    using string_type = String<char, std::char_traits<char>, Allocator<char>>;
-    using object_type = Object<string_type, json_type, std::less<string_type>,
-                               Allocator<std::pair<const string_type, json_type>>>;
-    using array_type = Array<json_type, Allocator<json_type>>;
-};
-
-using default_json_traits =
-    basic_json_traits<std::basic_string, std::map, vector, memory_pool>;
-using __default_json_string = typename json::default_json_traits::string_type;
-
-template <typename Traits>
-class basic_json {};
-
-} // namespace wjr::json
-
-namespace wjr {
-WJR_REGISTER_STRING_UNINITIALIZED_RESIZE(default_json_string,
-                                         json::__default_json_string);
-}
-
-#endif // WJR_JSON_DOCUMENT_HPP__
\ No newline at end of file
diff --git a/include/wjr/json/json.hpp b/include/wjr/json/json.hpp
new file mode 100644
index 00000000..3a0b94af
--- /dev/null
+++ b/include/wjr/json/json.hpp
@@ -0,0 +1,725 @@
+#ifndef WJR_JSON_JSON_HPP__
+#define WJR_JSON_JSON_HPP__
+
+#include <map>
+
+#include <wjr/json/visitor.hpp>
+
+namespace wjr::json {
+
+template <typename Traits>
+class basic_json;
+
+template <template <typename Char, typename Traits, typename Alloc> typename String,
+          template <typename Key, typename Ty, typename Pr, typename Alloc>
+          typename Object,
+          template <typename T, typename Alloc> typename Array>
+struct basic_json_traits {
+private:
+    using json_type = basic_json<basic_json_traits>;
+
+public:
+    using string_type = String<char, std::char_traits<char>, memory_pool<char>>;
+    using object_type =
+        Object<string_type, uninitialized<json_type>, std::less<string_type>,
+               memory_pool<std::pair<const string_type, uninitialized<json_type>>>>;
+    using array_type =
+        Array<uninitialized<json_type>, memory_pool<uninitialized<json_type>>>;
+};
+
+using default_json_traits = basic_json_traits<std::basic_string, std::map, vector>;
+using __default_json_string = typename default_json_traits::string_type;
+
+using json = basic_json<default_json_traits>;
+
+namespace detail {
+
+template <typename Json>
+class basic_json_parser;
+
+} // namespace detail
+
+template <typename Traits>
+class basic_json {
+
+    friend class detail::basic_json_parser<basic_json>;
+
+public:
+    using traits_type = Traits;
+
+    using null_type = std::nullptr_t;
+    using boolean_type = bool;
+    using number_unsigned_type = uint64_t;
+    using number_signed_type = int64_t;
+    using number_float_type = double;
+    using string_type = typename traits_type::string_type;
+    using object_type = typename traits_type::object_type;
+    using array_type = typename traits_type::array_type;
+
+    basic_json() = default;
+    basic_json(const basic_json &other) = delete;
+
+    basic_json(basic_json &&other) noexcept : m_value(other.m_value) {
+        other.m_value.m_type = value_t::null;
+    }
+
+    basic_json &operator=(const basic_json &other) = delete;
+
+    basic_json &operator=(basic_json &&other) noexcept {
+        if (WJR_UNLIKELY(this == std::addressof(other))) {
+            return *this;
+        }
+
+        m_value = other.m_value;
+        other.m_value.m_type = value_t::null;
+        return *this;
+    }
+
+    /**
+     * @brief Destroy the basic json object
+     * @todo Optimize by not using recursion
+     *
+     */
+    ~basic_json() noexcept { __destroy_and_deallocate(); }
+
+    basic_json(null_t) noexcept : m_value(null_t()) {}
+    basic_json(boolean_t, bool f) noexcept : m_value(boolean_t(), f) {}
+    basic_json(number_signed_t, int64_t value) noexcept
+        : m_value(number_unsigned_t(), value) {}
+    basic_json(number_unsigned_t, uint64_t value) noexcept
+        : m_value(number_signed_t(), value) {}
+    basic_json(number_float_t, double value) noexcept
+        : m_value(number_float_t(), value) {}
+
+    basic_json(string_t, string_type *ptr) noexcept : m_value(string_t(), ptr) {}
+    basic_json(object_t, object_type *ptr) noexcept : m_value(object_t(), ptr) {}
+    basic_json(array_t, array_type *ptr) noexcept : m_value(array_t(), ptr) {}
+
+    basic_json(basic_value value) noexcept : m_value(value) {}
+
+    WJR_PURE value_t type() const noexcept { return m_value.m_type; }
+
+    static result<basic_json> parse(const reader &rd) noexcept;
+
+private:
+    struct __stack_node {
+        __stack_node() = delete;
+
+        __stack_node(object_t, basic_json *p,
+                     typename object_type::iterator iter) noexcept
+            : ptr(p), object_iter(iter) {}
+
+        __stack_node(array_t, basic_json *p, typename array_type::iterator iter) noexcept
+            : ptr(p), array_iter(iter) {}
+
+        __stack_node(const __stack_node &) = delete;
+        __stack_node(__stack_node &&) = delete;
+
+        ~__stack_node() noexcept {}
+
+        basic_json *ptr;
+        union {
+            typename object_type::iterator object_iter;
+            typename array_type::iterator array_iter;
+        };
+    };
+
+    static void __destroy(basic_json *current);
+
+    WJR_CONSTEXPR20 void __destroy() { __destroy(this); }
+
+    WJR_CONSTEXPR20 void __destroy_and_deallocate() { __destroy(); }
+
+    WJR_PURE boolean_type &__get_boolean() noexcept { return m_value.m_boolean; }
+    WJR_PURE const boolean_type &__get_boolean() const noexcept {
+        return m_value.m_boolean;
+    }
+
+    WJR_PURE number_unsigned_type &__get_number_unsigned() noexcept {
+        return m_value.m_number_unsigned;
+    }
+    WJR_PURE const number_unsigned_type &__get_number_unsigned() const noexcept {
+        return m_value.m_number_unsigned;
+    }
+
+    WJR_PURE number_signed_type &__get_number_signed() noexcept {
+        return m_value.m_number_signed;
+    }
+    WJR_PURE const number_signed_type &__get_number_signed() const noexcept {
+        return m_value.m_number_signed;
+    }
+
+    WJR_PURE number_float_type &__get_number_float() noexcept {
+        return m_value.m_number_float;
+    }
+    WJR_PURE const number_float_type &__get_number_float() const noexcept {
+        return m_value.m_number_float;
+    }
+
+    WJR_PURE string_type &__get_string() noexcept {
+        return *static_cast<string_type *>(m_value.m_ptr);
+    }
+    WJR_PURE const string_type &__get_string() const noexcept {
+        return *static_cast<const string_type *>(m_value.m_ptr);
+    }
+
+    WJR_PURE object_type &__get_object() noexcept {
+        return *static_cast<object_type *>(m_value.m_ptr);
+    }
+    WJR_PURE const object_type &__get_object() const noexcept {
+        return *static_cast<const object_type *>(m_value.m_ptr);
+    }
+
+    WJR_PURE array_type &__get_array() noexcept {
+        return *static_cast<array_type *>(m_value.m_ptr);
+    }
+    WJR_PURE const array_type &__get_array() const noexcept {
+        return *static_cast<const array_type *>(m_value.m_ptr);
+    }
+
+    basic_value m_value;
+};
+
+template <typename Traits>
+void basic_json<Traits>::__destroy(basic_json *current) {
+    switch (current->type()) {
+    case value_t::null:
+    case value_t::boolean:
+    case value_t::number_unsigned:
+    case value_t::number_signed:
+    case value_t::number_float: {
+        return;
+    }
+    case value_t::string: {
+        memory_pool<string_type> al;
+        auto &str = current->__get_string();
+        std::destroy_at(std::addressof(str));
+        al.deallocate(std::addressof(str), 1);
+        break;
+    }
+    default: {
+        break;
+    }
+    }
+
+    lazy_initialized<__stack_node> parent;
+    lazy_initialized<static_vector<__stack_node, 256>> stk;
+
+    switch (current->type()) {
+    case value_t::object: {
+        auto &obj = current->__get_object();
+        const auto iter = obj.begin();
+
+        if (WJR_UNLIKELY(iter == obj.end())) {
+            memory_pool<object_type> al;
+            std::destroy_at(std::addressof(obj));
+            al.deallocate(std::addressof(obj), 1);
+            return;
+        }
+
+        parent.emplace(object_t(), current, iter);
+        current = iter->second.get();
+        stk.emplace();
+        goto OBJECT_ELEMENT;
+    }
+    case value_t::array: {
+        auto &arr = current->__get_array();
+        const auto iter = arr.begin();
+
+        if (WJR_UNLIKELY(iter == arr.end())) {
+            memory_pool<array_type> al;
+            std::destroy_at(std::addressof(arr));
+            al.deallocate(std::addressof(arr), 1);
+            return;
+        }
+
+        parent.emplace(array_t(), current, iter);
+        current = std::addressof(**iter);
+        stk.emplace();
+        goto ARRAY_ELEMENT;
+    }
+    default: {
+        WJR_UNREACHABLE();
+        break;
+    }
+    }
+
+OBJECT_ELEMENT : {
+    switch (current->type()) {
+    case value_t::null:
+    case value_t::boolean:
+    case value_t::number_unsigned:
+    case value_t::number_signed:
+    case value_t::number_float: {
+        break;
+    }
+    case value_t::string: {
+        memory_pool<string_type> al;
+        auto &str = current->__get_string();
+        std::destroy_at(std::addressof(str));
+        al.deallocate(std::addressof(str), 1);
+        break;
+    }
+    case value_t::object: {
+        auto &obj = current->__get_object();
+        const auto iter = obj.begin();
+
+        if (WJR_UNLIKELY(iter == obj.end())) {
+            memory_pool<object_type> al;
+            std::destroy_at(std::addressof(obj));
+            al.deallocate(std::addressof(obj), 1);
+            break;
+        }
+
+        stk->emplace_back(object_t(), parent->ptr, parent->object_iter);
+        parent->ptr = current;
+        parent->object_iter = iter;
+        current = std::addressof(*iter->second);
+        goto OBJECT_ELEMENT;
+    }
+    case value_t::array: {
+        auto &arr = current->__get_array();
+        const auto iter = arr.begin();
+
+        if (WJR_UNLIKELY(iter == arr.end())) {
+            memory_pool<array_type> al;
+            std::destroy_at(std::addressof(arr));
+            al.deallocate(std::addressof(arr), 1);
+            break;
+        }
+
+        stk->emplace_back(object_t(), parent->ptr, parent->object_iter);
+        parent->ptr = current;
+        parent->array_iter = iter;
+        current = std::addressof(**iter);
+        goto ARRAY_ELEMENT;
+    }
+    }
+
+    do {
+        current = parent->ptr;
+        const auto iter = ++parent->object_iter;
+        if (iter != current->__get_object().end()) {
+            current = std::addressof(*iter->second);
+            goto OBJECT_ELEMENT;
+        }
+
+        memory_pool<object_type> al;
+        std::destroy_at(std::addressof(current->__get_object()));
+        al.deallocate(std::addressof(current->__get_object()), 1);
+    } while (0);
+
+    do {
+        if (stk->empty()) {
+            return;
+        }
+
+        auto &node = stk->back();
+        stk->pop_back();
+
+        current = node.ptr;
+        if (current->type() == value_t::object) {
+            const auto iter = ++node.object_iter;
+            if (iter != current->__get_object().end()) {
+                parent->ptr = current;
+                parent->object_iter = node.object_iter;
+                current = std::addressof(*iter->second);
+                goto OBJECT_ELEMENT;
+            }
+
+            memory_pool<object_type> al;
+            std::destroy_at(std::addressof(current->__get_object()));
+            al.deallocate(std::addressof(current->__get_object()), 1);
+        } else {
+            const auto iter = ++node.array_iter;
+            if (iter != current->__get_array().end()) {
+                parent->ptr = current;
+                parent->array_iter = node.array_iter;
+                current = std::addressof(**iter);
+                goto ARRAY_ELEMENT;
+            }
+
+            memory_pool<array_type> al;
+            std::destroy_at(std::addressof(current->__get_array()));
+            al.deallocate(std::addressof(current->__get_array()), 1);
+        }
+    } while (true);
+}
+
+ARRAY_ELEMENT : {
+    switch (current->type()) {
+    case value_t::null:
+    case value_t::boolean:
+    case value_t::number_unsigned:
+    case value_t::number_signed:
+    case value_t::number_float: {
+        break;
+    }
+    case value_t::string: {
+        memory_pool<string_type> al;
+        auto &str = current->__get_string();
+        std::destroy_at(std::addressof(str));
+        al.deallocate(std::addressof(str), 1);
+        break;
+    }
+    case value_t::object: {
+        auto &obj = current->__get_object();
+        const auto iter = obj.begin();
+
+        if (WJR_UNLIKELY(iter == obj.end())) {
+            memory_pool<object_type> al;
+            std::destroy_at(std::addressof(obj));
+            al.deallocate(std::addressof(obj), 1);
+            break;
+        }
+
+        stk->emplace_back(array_t(), parent->ptr, parent->array_iter);
+        parent->ptr = current;
+        parent->object_iter = iter;
+        current = std::addressof(*iter->second);
+        goto OBJECT_ELEMENT;
+    }
+    case value_t::array: {
+        auto &arr = current->__get_array();
+        const auto iter = arr.begin();
+
+        if (WJR_UNLIKELY(iter == arr.end())) {
+            memory_pool<array_type> al;
+            std::destroy_at(std::addressof(arr));
+            al.deallocate(std::addressof(arr), 1);
+            break;
+        }
+
+        stk->emplace_back(array_t(), parent->ptr, parent->array_iter);
+        parent->ptr = current;
+        parent->array_iter = iter;
+        current = std::addressof(**iter);
+        goto ARRAY_ELEMENT;
+    }
+    }
+
+    do {
+        current = parent->ptr;
+        const auto iter = ++parent->array_iter;
+        if (iter != current->__get_array().end()) {
+            current = std::addressof(**iter);
+            goto ARRAY_ELEMENT;
+        }
+
+        memory_pool<array_type> al;
+        std::destroy_at(std::addressof(current->__get_array()));
+        al.deallocate(std::addressof(current->__get_array()), 1);
+    } while (0);
+
+    do {
+        if (stk->empty()) {
+            return;
+        }
+
+        auto &node = stk->back();
+        stk->pop_back();
+
+        current = node.ptr;
+        if (current->type() == value_t::object) {
+            const auto iter = ++node.object_iter;
+            if (iter != current->__get_object().end()) {
+                parent->ptr = current;
+                parent->object_iter = node.object_iter;
+                current = std::addressof(*iter->second);
+                goto OBJECT_ELEMENT;
+            }
+
+            memory_pool<object_type> al;
+            std::destroy_at(std::addressof(current->__get_object()));
+            al.deallocate(std::addressof(current->__get_object()), 1);
+        } else {
+            const auto iter = ++node.array_iter;
+            if (iter != current->__get_array().end()) {
+                parent->ptr = current;
+                parent->array_iter = node.array_iter;
+                current = std::addressof(**iter);
+                goto ARRAY_ELEMENT;
+            }
+
+            memory_pool<array_type> al;
+            std::destroy_at(std::addressof(current->__get_array()));
+            al.deallocate(std::addressof(current->__get_array()), 1);
+        }
+    } while (true);
+}
+}
+
+namespace detail {
+
+template <typename Json>
+class basic_json_parser {
+    template <typename Parser>
+    friend result<void> visitor_detail::parse(Parser &&par, const reader &rd) noexcept;
+
+    using json_type = Json;
+    using string_type = typename json_type::string_type;
+    using object_type = typename json_type::object_type;
+    using array_type = typename json_type::array_type;
+
+public:
+    WJR_INTRINSIC_INLINE result<json_type> parse(const reader &rd) noexcept {
+        json_type j;
+        current = std::addressof(j);
+        WJR_EXPECTED_INIT(ret, visitor_detail::parse(*this, rd));
+        return j;
+    }
+
+protected:
+    WJR_INTRINSIC_INLINE result<void> visit_root_null(const char *first) const noexcept {
+        wjr::construct_at(current, null_t());
+        return detail::check_null(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void>
+    visit_object_null(const char *first) const noexcept {
+        wjr::construct_at(element, null_t());
+        return detail::check_null(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_array_null(const char *first) const noexcept {
+        current->__get_array().emplace_back(null_t());
+        return detail::check_null(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_root_true(const char *first) const noexcept {
+        wjr::construct_at(current, null_t());
+        return detail::check_true(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void>
+    visit_object_true(const char *first) const noexcept {
+        wjr::construct_at(element, boolean_t(), true);
+        return detail::check_true(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_array_true(const char *first) const noexcept {
+        current->__get_array().emplace_back(boolean_t(), true);
+        return detail::check_true(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_root_false(const char *first) const noexcept {
+        wjr::construct_at(current, boolean_t(), false);
+        return detail::check_false(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void>
+    visit_object_false(const char *first) const noexcept {
+        wjr::construct_at(element, boolean_t(), false);
+        return detail::check_false(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void>
+    visit_array_false(const char *first) const noexcept {
+        current->__get_array().emplace_back(boolean_t(), false);
+        return detail::check_false(first);
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_root_number(const char *first,
+                                                        const char *last) const noexcept {
+        WJR_EXPECTED_INIT(ret, detail::parse_number(first, last));
+        wjr::construct_at(current, *ret);
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void>
+    visit_object_number(const char *first, const char *last) const noexcept {
+        WJR_EXPECTED_INIT(ret, detail::parse_number(first, last));
+        wjr::construct_at(element, *ret);
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void>
+    visit_array_number(const char *first, const char *last) const noexcept {
+        WJR_EXPECTED_INIT(ret, detail::parse_number(first, last));
+        current->__get_array().emplace_back(*ret);
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_root_string(const char *first,
+                                                        const char *last) const noexcept {
+        memory_pool<string_type> al;
+        string_type *str = al.allocate(1);
+        wjr::construct_at(str);
+        try_uninitialized_resize(*str, last - first);
+        auto ret = detail::parse_string(str->data(), first, last);
+        if (WJR_UNLIKELY(!ret)) {
+            std::destroy_at(str);
+            al.deallocate(str, 1);
+            return unexpected(std::move(ret).error());
+        }
+        str->resize(*ret - str->data());
+        wjr::construct_at(current, string_t(), str);
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void>
+    visit_object_string(const char *first, const char *last) const noexcept {
+        memory_pool<string_type> al;
+        string_type *str = al.allocate(1);
+        wjr::construct_at(str);
+        try_uninitialized_resize(*str, last - first);
+        auto ret = detail::parse_string(str->data(), first, last);
+        if (WJR_UNLIKELY(!ret)) {
+            std::destroy_at(str);
+            al.deallocate(str, 1);
+            return unexpected(std::move(ret).error());
+        }
+        str->resize(*ret - str->data());
+        wjr::construct_at(element, string_t(), str);
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void>
+    visit_array_string(const char *first, const char *last) const noexcept {
+        memory_pool<string_type> al;
+        string_type *str = al.allocate(1);
+        wjr::construct_at(str);
+        try_uninitialized_resize(*str, last - first);
+        auto ret = detail::parse_string(str->data(), first, last);
+        if (WJR_UNLIKELY(!ret)) {
+            std::destroy_at(str);
+            al.deallocate(str, 1);
+            return unexpected(std::move(ret).error());
+        }
+        str->resize(*ret - str->data());
+        current->__get_array().emplace_back(string_t(), str);
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_object_key_string(const char *first,
+                                                              const char *last) noexcept {
+        string_type str;
+        try_uninitialized_resize(str, last - first);
+        WJR_EXPECTED_INIT(ret, detail::parse_string(str.data(), first, last));
+        str.resize(*ret - str.data());
+        const auto iter = current->__get_object().emplace(std::move(str), dctor);
+        WJR_ASSUME(str.size() == 0);
+        element = iter.first->second.get();
+        if (WJR_UNLIKELY(!iter.second)) {
+            (iter.first)->second.reset();
+            return {};
+        }
+
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_root_start_object(uint32_t) const noexcept {
+        memory_pool<object_type> al;
+        object_type *const obj = al.allocate(1);
+        wjr::construct_at(obj);
+        wjr::construct_at(current, object_t(), obj);
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_object_start_object(uint32_t) noexcept {
+        memory_pool<object_type> al;
+        object_type *const obj = al.allocate(1);
+        wjr::construct_at(obj);
+        wjr::construct_at(element, object_t(), obj);
+        stk.emplace_back(current);
+        current = element;
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_array_start_object(uint32_t) noexcept {
+        memory_pool<object_type> al;
+        object_type *const obj = al.allocate(1);
+        wjr::construct_at(obj);
+        stk.emplace_back(current);
+        current = current->__get_array().emplace_back(object_t(), obj).get();
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_root_start_array(uint32_t) const noexcept {
+        memory_pool<array_type> al;
+        array_type *const arr = al.allocate(1);
+        wjr::construct_at(arr);
+        wjr::construct_at(current, array_t(), arr);
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_object_start_array(uint32_t) noexcept {
+        memory_pool<array_type> al;
+        array_type *const arr = al.allocate(1);
+        wjr::construct_at(arr);
+        wjr::construct_at(element, array_t(), arr);
+        stk.emplace_back(current);
+        current = element;
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_array_start_array(uint32_t) noexcept {
+        memory_pool<array_type> al;
+        array_type *const arr = al.allocate(1);
+        wjr::construct_at(arr);
+        stk.emplace_back(current);
+        current = current->__get_array().emplace_back(array_t(), arr).get();
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_end_object_to_object(uint32_t) noexcept {
+        current = stk.back();
+        stk.pop_back();
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_end_object_to_array(uint32_t) noexcept {
+        current = stk.back();
+        stk.pop_back();
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_end_object_to_root(uint32_t) const noexcept {
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_end_array_to_object(uint32_t) noexcept {
+        current = stk.back();
+        stk.pop_back();
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_end_array_to_array(uint32_t) noexcept {
+        current = stk.back();
+        stk.pop_back();
+        return {};
+    }
+
+    WJR_INTRINSIC_INLINE result<void> visit_end_array_to_root(uint32_t) const noexcept {
+        return {};
+    }
+
+private:
+    static_vector<json_type *, 256> stk;
+    json_type *current;
+    json_type *element;
+};
+
+} // namespace detail
+
+template <typename Traits>
+result<basic_json<Traits>> basic_json<Traits>::parse(const reader &rd) noexcept {
+    detail::basic_json_parser<basic_json<Traits>> par;
+    return par.parse(rd);
+}
+
+} // namespace wjr::json
+
+namespace wjr {
+
+template <typename Traits>
+struct get_relocate_mode<json::basic_json<Traits>> {
+    static constexpr relocate_t value = relocate_t::trivial;
+};
+
+WJR_REGISTER_STRING_UNINITIALIZED_RESIZE(default_json_string,
+                                         json::__default_json_string);
+
+} // namespace wjr
+
+#endif // WJR_JSON_JSON_HPP__
\ No newline at end of file
diff --git a/include/wjr/json/number.hpp b/include/wjr/json/number.hpp
index d01bd64a..bb95c286 100644
--- a/include/wjr/json/number.hpp
+++ b/include/wjr/json/number.hpp
@@ -19,17 +19,17 @@ struct number_writer {
     WJR_INTRINSIC_CONSTEXPR number_writer(basic_value &_value) noexcept : value(_value) {}
 
     WJR_INTRINSIC_CONSTEXPR uint64_t &get_u64() noexcept {
-        value.m_type = number_unsigned_v;
+        value.m_type = value_t::number_unsigned;
         return value.m_number_unsigned;
     }
 
     WJR_INTRINSIC_CONSTEXPR int64_t &get_i64() noexcept {
-        value.m_type = number_signed_v;
+        value.m_type = value_t::number_signed;
         return value.m_number_signed;
     }
 
     WJR_INTRINSIC_CONSTEXPR double &get_float() noexcept {
-        value.m_type = number_float_v;
+        value.m_type = value_t::number_float;
         return value.m_number_float;
     }
 
diff --git a/include/wjr/memory/uninitialized.hpp b/include/wjr/memory/uninitialized.hpp
index 29dd6cb2..90ecda87 100644
--- a/include/wjr/memory/uninitialized.hpp
+++ b/include/wjr/memory/uninitialized.hpp
@@ -694,6 +694,8 @@ struct __aligned_storage_t {
             std::is_nothrow_constructible_v<T, Args...>)                                 \
             : m_value(std::forward<Args>(args)...) {}                                    \
                                                                                          \
+        constexpr __uninitialized_base(enable_default_constructor_t) noexcept {}         \
+                                                                                         \
         ~__uninitialized_base() WJR_PP_BOOL_IF(DES, = default, noexcept {});             \
                                                                                          \
         union {                                                                          \
@@ -719,14 +721,15 @@ struct __uninitialized_control_base : __uninitialized_base_selector<T> {
     using Mybase = __uninitialized_base_selector<T>;
     using Mybase::Mybase;
 
-    WJR_CONSTEXPR20 std::enable_if_t<std::is_copy_constructible_v<T>>
+    template <typename U = T, WJR_REQUIRES(std::is_copy_constructible_v<U>)>
+    WJR_CONSTEXPR20 void
     __copy_construct(const __uninitialized_control_base &other) noexcept(
         std::is_nothrow_copy_constructible_v<T>) {
         wjr::construct_at(std::addressof(this->m_value), other.m_value);
     }
 
-    WJR_CONSTEXPR20 std::enable_if_t<std::is_move_constructible_v<T>>
-    __move_construct(__uninitialized_control_base &&other) noexcept(
+    template <typename U = T, WJR_REQUIRES(std::is_move_constructible_v<U>)>
+    WJR_CONSTEXPR20 void __move_construct(__uninitialized_control_base &&other) noexcept(
         std::is_nothrow_move_constructible_v<T>) {
         wjr::construct_at(std::addressof(this->m_value), std::move(other.m_value));
     }