Rename diff_target_values::small, which windows.h defines as a macro

<windows.h> (rpcndr.h) defines small as char, so test-windows_h did not
compile with MSVC.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/api/basic_json_view/at.md

@@ -80,8 +80,7 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
    Objects with 128 or more members get a hash index of their keys while parsing, so that a lookup in them takes
    constant time on average.
 2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
-   index (unlike `BasicJsonType`'s array, which is random-access). Constant if no element of the array is an array
-   or object, since the elements are then adjacent in the index.
+   index (unlike `BasicJsonType`'s array, which is random-access).
 3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
    that level (as 1.) or the index into the array (as 2.).
 

docs/mkdocs/docs/api/basic_json_view/back.md

@@ -28,8 +28,7 @@ This exception does not carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.
 
 Linear in the size of the array or object: unlike [`front()`](front.md), which only ever looks at the first
 element, `back()` has to walk every element to find where they end, since elements are not a fixed size in the
-index. Constant for an array none of whose elements is an array or object, since the elements are then adjacent
-in the index.
+index.
 
 ## Notes
 

docs/mkdocs/docs/api/basic_json_view/operator[].md

@@ -86,8 +86,7 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
    Objects with 128 or more members get a hash index of their keys while parsing, so that a lookup in them takes
    constant time on average.
 2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
-   index (unlike `BasicJsonType`'s array, which is random-access). Constant if no element of the array is an array
-   or object, since the elements are then adjacent in the index.
+   index (unlike `BasicJsonType`'s array, which is random-access).
 3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
    that level (as 1.) or the index into the array (as 2.).
 

include/nlohmann/detail/json_pointer.hpp

@@ -15,7 +15,7 @@
 #include <cstddef> // size_t
 #include <cstdint> // uint64_t
 #include <cstdlib> // strtoull
-#include <cstring> // memcmp, memcpy
+#include <cstring> // memchr, memcmp, memcpy
 #ifndef JSON_NO_IO
     #include <iosfwd> // ostream
 #endif  // JSON_NO_IO
@@ -303,6 +303,12 @@ class json_pointer
         exceeds_size_type  ///< @a s converts to an integer that exceeds size_type
     };
 
+    /// whether a reference token is "-" (a plain comparison with a string literal is not always inlined)
+    static bool is_dash(const string_t& s) noexcept
+    {
+        return s.size() == 1 && s[0] == '-';
+    }
+
     /*!
     @param[in] s    reference token to be converted into an array index
     @param[out] idx the integer representation of @a s if @ref array_index_status::ok
@@ -328,7 +334,7 @@ class json_pointer
         // error condition (cf. RFC 6901, Sect. 4); this also covers single-
         // character tokens, so "/x" and "/xy" fail alike; "-" and the empty
         // token are left to the conversion below and are reported as unresolved
-        if (JSON_HEDLEY_UNLIKELY(!s.empty() && s != "-" && !(s[0] >= '0' && s[0] <= '9')))
+        if (JSON_HEDLEY_UNLIKELY(!s.empty() && !is_dash(s) && !(s[0] >= '0' && s[0] <= '9')))
         {
             return array_index_status::not_a_number;
         }
@@ -475,9 +481,40 @@ class json_pointer
         return pos == size;
     }
 
+    /// reserve room for @a n elements of an array type that has reserve()
+    template<typename ArrayType>
+    static auto reserve_elements(ArrayType& array, const std::size_t n, detail::priority_tag<1> /*unused*/)
+    -> decltype(array.reserve(n), void())
+    {
+        array.reserve(n);
+    }
+
+    template<typename ArrayType>
+    static void reserve_elements(ArrayType& /*array*/, const std::size_t /*n*/, detail::priority_tag<0> /*unused*/)
+    {}
+
     /// @brief object member access with a key that is only copied if it is inserted
+    ///
+    /// Objects that can find the position of a key and insert there
+    /// (std::map) search once, others look the key up and add it if it is missing.
     template<typename BasicJsonType>
-    static BasicJsonType& object_member(BasicJsonType& object, const string_t& key)
+    static auto object_member_impl(BasicJsonType& object, const string_t& key, detail::priority_tag<1> /*unused*/)
+    -> decltype(object.m_data.m_value.object->emplace_hint(object.m_data.m_value.object->lower_bound(key), key, nullptr), std::declval<BasicJsonType&>())
+    {
+        auto& members = *object.m_data.m_value.object;
+        auto it = members.lower_bound(key);
+        if (it != members.end() && !members.key_comp()(key, it->first))
+        {
+            return it->second;
+        }
+
+        const auto old_capacity = object.container_capacity();
+        it = members.emplace_hint(it, key, nullptr);
+        return object.set_parent_after_insert(it->second, old_capacity);
+    }
+
+    template<typename BasicJsonType>
+    static BasicJsonType& object_member_impl(BasicJsonType& object, const string_t& key, detail::priority_tag<0> /*unused*/)
     {
         auto& members = *object.m_data.m_value.object;
         const auto it = members.find(key);
@@ -488,6 +525,12 @@ class json_pointer
         return object.operator[](key);
     }
 
+    template<typename BasicJsonType>
+    static BasicJsonType& object_member(BasicJsonType& object, const string_t& key)
+    {
+        return object_member_impl(object, key, detail::priority_tag<1> {});
+    }
+
   JSON_PRIVATE_UNLESS_TESTED:
     json_pointer top() const
     {
@@ -720,48 +763,103 @@ class json_pointer
         }
     }
 
+    /*!
+    @brief the values along the pointer last resolved by @ref resolve_plain
+
+    A patch from @ref basic_json::diff lists its operations in document order,
+    so consecutive pointers share most of their reference tokens; the values
+    along the previous pointer are kept to resume from the common prefix.
+    `steps[k]` is the value after the first `k` reference tokens together with
+    the length of the prefix of `*path` that holds them. A value stays valid as
+    long as no operation changes its container: callers keep only values up to
+    the parent of the pointer they modify, or call `reset()`.
+    */
+    template<typename BasicJsonType>
+    struct plain_steps
+    {
+        const string_t* path = nullptr;
+        std::vector<std::pair<std::size_t, BasicJsonType*>> steps{};
+
+        void reset() noexcept
+        {
+            path = nullptr;
+            steps.clear();
+        }
+    };
+
     /*!
     @brief resolve a plain JSON pointer without building its reference tokens
 
-    @param[in] ptr     the value the pointer starts at
+    @param[in] root    the value the pointer starts at
     @param[in] path    a JSON pointer string
     @param[in] length  the number of leading bytes of @a path to resolve; 0 or
                        the position of a slash
     @param[in,out] token  a string to hold the reference tokens, to reuse its storage
+    @param[in,out] cache  the values along the previously resolved pointer;
+                          @a path must outlive the next call
 
     @return the pointed to value, or `nullptr` if the pointer does not denote
-            an existing value, or does so in a way that is not plain: a
-            reference token with an escape, an array index that is malformed or
-            out of range, or a "-". No exception is thrown for these; callers
-            use @ref json_pointer instead, which handles them.
+            an existing value, or does so in a way that is not plain: an array
+            index that is malformed or out of range, or a "-", or a reference
+            token with an escape. No exception is
+            thrown for these; callers use @ref json_pointer instead, which
+            handles them.
     */
     template<typename BasicJsonType>
-    static BasicJsonType* resolve_plain(BasicJsonType* ptr, const string_t& path, const std::size_t length, string_t& token)
+    static BasicJsonType* resolve_plain(BasicJsonType* root, const string_t& path, const std::size_t length, string_t& token, plain_steps<BasicJsonType>& cache)
     {
-        for (std::size_t pos = 0; pos < length;)
+        auto& steps = cache.steps;
+
+        // resume from the deepest step that is also a prefix of this path
+        std::size_t depth = 1;
+        if (cache.path != nullptr && !steps.empty() && steps[0].second == root)
+        {
+            const string_t& previous = *cache.path;
+            for (depth = steps.size(); depth > 1; --depth)
+            {
+                // a step ends at a token boundary of the previous path
+                const std::size_t prefix = steps[depth - 1].first;
+                if (prefix <= length && (prefix == length || path[prefix] == '/') && std::memcmp(path.data(), previous.data(), prefix) == 0)
+                {
+                    break;
+                }
+            }
+            steps.resize(depth);
+        }
+        else
+        {
+            steps.assign(1, std::make_pair(std::size_t{0}, root));
+        }
+        cache.path = &path;
+
+        BasicJsonType* ptr = steps[depth - 1].second;
+        for (std::size_t pos = steps[depth - 1].first; pos < length;)
         {
             if (JSON_HEDLEY_UNLIKELY(path[pos] != '/'))
             {
                 return nullptr;
             }
 
-            // the reference token between the slash at pos and the next one
-            std::size_t end = path.find_first_of('/', pos + 1);
-            if (end == string_t::npos || end > length)
+            // the reference token between the slash at pos and the next one,
+            // which must not have an escape
+            const char* const begin = path.data() + pos + 1;
+            const char* const limit = path.data() + length;
+            const char* end = begin;
+            while (end < limit && *end != '/')
             {
-                end = length;
-            }
-            token.clear();
-            token.append(path.data() + pos + 1, end - pos - 1);
-            if (JSON_HEDLEY_UNLIKELY(token.find_first_of('~') != string_t::npos))
-            {
-                return nullptr;
+                if (JSON_HEDLEY_UNLIKELY(*end == '~'))
+                {
+                    return nullptr;
+                }
+                ++end;
             }
 
             switch (ptr->type())
             {
                 case detail::value_t::object:
                 {
+                    token.clear();
+                    token.append(begin, static_cast<std::size_t>(end - begin));
                     const auto it = ptr->m_data.m_value.object->find(token);
                     if (JSON_HEDLEY_UNLIKELY(it == ptr->m_data.m_value.object->end()))
                     {
@@ -773,8 +871,24 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    typename BasicJsonType::size_type idx{};
-                    if (JSON_HEDLEY_UNLIKELY(parse_array_index<BasicJsonType>(token, idx) != array_index_status::ok || idx >= ptr->m_data.m_value.array->size()))
+                    // an index of up to 18 digits without a leading zero fits into size_type
+                    // (9 digits for a 32-bit size_type); everything else is left to json_pointer
+                    constexpr std::size_t max_digits = sizeof(typename BasicJsonType::size_type) >= 8 ? 18 : 9;
+                    const std::size_t digits = static_cast<std::size_t>(end - begin);
+                    if (JSON_HEDLEY_UNLIKELY(digits == 0 || digits > max_digits || (digits > 1 && *begin == '0')))
+                    {
+                        return nullptr;
+                    }
+                    typename BasicJsonType::size_type idx = 0;
+                    for (const char* c = begin; c != end; ++c)
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(*c < '0' || *c > '9'))
+                        {
+                            return nullptr;
+                        }
+                        idx = static_cast<typename BasicJsonType::size_type>((idx * 10) + static_cast<typename BasicJsonType::size_type>(*c - '0'));
+                    }
+                    if (JSON_HEDLEY_UNLIKELY(idx >= ptr->m_data.m_value.array->size()))
                     {
                         return nullptr;
                     }
@@ -793,7 +907,8 @@ class json_pointer
                 default:
                     return nullptr;
             }
-            pos = end;
+            pos = static_cast<std::size_t>(end - path.data());
+            steps.emplace_back(pos, ptr);
         }
 
         return ptr;
@@ -907,7 +1022,7 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    if (JSON_HEDLEY_UNLIKELY(is_dash(reference_token)))
                     {
                         // "-" always fails the range check
                         JSON_THROW(detail::out_of_range::create(detail::exception_id::pointer_past_the_end_index, detail::concat(
@@ -978,7 +1093,7 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    if (JSON_HEDLEY_UNLIKELY(is_dash(reference_token)))
                     {
                         // "-" cannot be used for const access
                         JSON_THROW(detail::out_of_range::create(detail::exception_id::pointer_past_the_end_index, detail::concat("array index '-' (", std::to_string(ptr->m_data.m_value.array->size()), ") is out of range"), ptr));
@@ -1040,7 +1155,7 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    if (JSON_HEDLEY_UNLIKELY(is_dash(reference_token)))
                     {
                         // "-" always fails the range check
                         return nullptr;
@@ -1117,7 +1232,7 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    if (JSON_HEDLEY_UNLIKELY(is_dash(reference_token)))
                     {
                         // "-" always fails the range check
                         return false;
@@ -1276,6 +1391,52 @@ class json_pointer
         obj[key] = std::forward<ValueType>(v);
     }
 
+    /// the number of entries that flattening @a value adds: its primitive
+    /// values and empty containers
+    template<typename BasicJsonType>
+    static std::size_t count_flattened(const BasicJsonType& value)
+    {
+        std::size_t count = 0;
+        std::vector<const BasicJsonType*> pending(1, &value);
+        while (!pending.empty())
+        {
+            const BasicJsonType* const v = pending.back();
+            pending.pop_back();
+            if (v->is_array() && !v->m_data.m_value.array->empty())
+            {
+                for (const auto& element : *v->m_data.m_value.array)
+                {
+                    pending.push_back(&element);
+                }
+            }
+            else if (v->is_object() && !v->m_data.m_value.object->empty())
+            {
+                for (const auto& member : *v->m_data.m_value.object)
+                {
+                    pending.push_back(&member.second);
+                }
+            }
+            else
+            {
+                ++count;
+            }
+        }
+        return count;
+    }
+
+    // Reserve the storage for @a value of objects that have a reserve(), so
+    // that it does not have to be moved while it grows
+    template<typename ObjectType, typename BasicJsonType>
+    static auto reserve_flattened(ObjectType& obj, const BasicJsonType& value, detail::priority_tag<1> /*unused*/)
+    -> decltype(obj.reserve(std::size_t {}), void())
+    {
+        obj.reserve(count_flattened(value));
+    }
+
+    template<typename ObjectType, typename BasicJsonType>
+    static void reserve_flattened(ObjectType& /*obj*/, const BasicJsonType& /*value*/, detail::priority_tag<0> /*unused*/)
+    {}
+
     /// append the decimal representation of @a i to @a out
     static void append_index(string_t& out, std::size_t i)
     {
@@ -1385,6 +1546,7 @@ class json_pointer
             }
         };
 
+        reserve_flattened(object, value, detail::priority_tag<1> {});
         enter(value);
         while (!stack.empty())
         {
@@ -1392,8 +1554,9 @@ class json_pointer
             // frame, which would invalidate a reference to it
             const BasicJsonType* const container = stack.back().container;
 
-            // drop the path of the previous child
-            path.resize(stack.back().path_length);
+            // the path of the previous child is replaced by the path of the
+            // next one; for an array element in one resize
+            const std::size_t path_length = stack.back().path_length;
 
             if (container->is_array())
             {
@@ -1407,8 +1570,20 @@ class json_pointer
 
                 // iterate array and use index as a reference string
                 ++stack.back().index;
-                path.push_back('/');
-                append_index(path, i);
+                std::array<char, 24> digits{};
+                std::size_t pos = digits.size();
+                std::size_t rest = i;
+                do
+                {
+                    digits[--pos] = static_cast<char>('0' + rest % 10);
+                    rest /= 10;
+                }
+                while (rest != 0);
+                const std::size_t count = digits.size() - pos;
+                path.resize(path_length + 1 + count);
+                char* const out = &path[path_length];
+                out[0] = '/';
+                std::memcpy(out + 1, digits.data() + pos, count);
                 enter(array[i]);
             }
             else
@@ -1422,6 +1597,7 @@ class json_pointer
 
                 // iterate object and use keys as reference string
                 ++stack.back().member;
+                path.resize(path_length);
                 path.push_back('/');
                 detail::escape_into(path, it->first);
                 enter(it->second);
@@ -1517,8 +1693,28 @@ class json_pointer
                 {
                     end = key.size();
                 }
+                const std::size_t token_size = end - pos - 1;
+
+                // a token that is a plain index of up to 9 digits, which is
+                // the case for almost all array elements, is not copied
+                std::size_t index = 0;
+                bool plain_index = current->type() == detail::value_t::array && token_size != 0 && token_size <= 9 && (token_size == 1 || data[pos + 1] != '0');
+                for (std::size_t k = pos + 1; plain_index && k < end; ++k)
+                {
+                    plain_index = data[k] >= '0' && data[k] <= '9';
+                    index = (index * 10) + static_cast<std::size_t>(data[k] - '0');
+                }
+                if (plain_index)
+                {
+                    current = &current->operator[](static_cast<typename BasicJsonType::size_type>(index));
+                    values.push_back(current);
+                    ends.push_back(end);
+                    pos = end;
+                    continue;
+                }
+
                 token.clear();
-                token.append(data + pos + 1, end - pos - 1);
+                token.append(data + pos + 1, token_size);
                 if (token.find_first_of('~') != string_t::npos)
                 {
                     detail::unescape(token);
@@ -1528,10 +1724,13 @@ class json_pointer
                 {
                     case detail::value_t::null:
                     {
-                        if (arrays.contains(data, pos))
+                        // a first child 0 makes the value an array without a look-up
+                        if ((token_size == 1 && data[pos + 1] == '0') || arrays.contains(data, pos))
                         {
                             // some reference token below this position is 0, so the
                             // value is an array
+                            *current = BasicJsonType(detail::value_t::array);
+                            reserve_elements(*current->m_data.m_value.array, 2, detail::priority_tag<1> {});
                             current = &current->operator[](array_index<BasicJsonType>(token));
                         }
                         else

include/nlohmann/detail/view/builder.hpp

@@ -275,41 +275,11 @@ class builder
                 0, 0, '\b', 0, 0, 0, '\f', 0, 0, 0, 0, 0, 0, 0, '\n', 0, 0, 0, '\r', 0, '\t', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
             }
         };
-        // The write position is kept in locals: the stores of characters into
-        // the arena may alias the members of the builder, which would then be
-        // reloaded after every one. It is stored back where the arena grows
-        // and at the end.
-        const unsigned char* const end = m_end;
         const std::size_t start = arena_used();
-        char* w = m_arena_write;
-        const char* w_end = m_arena_end;
-#define NLOHMANN_VIEW_ENSURE(n)                                                       \
-    if (NLOHMANN_VIEW_UNLIKELY(static_cast<std::size_t>(w_end - w) < (n)))            \
-    {                                                                                 \
-        m_arena_write = w;                                                            \
-        arena_grow(n);                                                                \
-        w = m_arena_write;                                                            \
-        w_end = m_arena_end;                                                          \
-    }
-        {
-            const auto n = static_cast<std::size_t>(p - s);
-            if (n <= 16 && end - s >= 16)
-            {
-                NLOHMANN_VIEW_ENSURE(16)
-                std::memcpy(w, s, 16);
-            }
-            else if (n != 0)
-            {
-                // (an empty run leaves an empty arena unallocated, and memcpy()
-                // must not be passed its null pointer even for zero bytes)
-                NLOHMANN_VIEW_ENSURE(n)
-                std::memcpy(w, s, n);
-            }
-            w += n;
-        }
+        arena_run(s, static_cast<std::size_t>(p - s));
         for (;;)
         {
-            if (p == end)
+            if (p == m_end)
             {
                 return failed(error_code::string_missing_quote, p);
             }
@@ -317,7 +287,6 @@ class builder
             if (c == '"')
             {
                 ++p;
-                m_arena_write = w;
                 return decoded{p, start, arena_used() - start};
             }
             if (c != '\\')
@@ -328,7 +297,7 @@ class builder
                 return failed(c < 0x20 ? error_code::string_control_character : error_code::string_utf8, p);
             }
             ++p;
-            if (p == end)
+            if (p == m_end)
             {
                 return failed(error_code::string_missing_quote, p);
             }
@@ -346,7 +315,7 @@ class builder
                     {
                         return failed(error_code::string_surrogate_low, p);
                     }
-                    if (end - p < 2 || p[0] != '\\' || p[1] != 'u')
+                    if (m_end - p < 2 || p[0] != '\\' || p[1] != 'u')
                     {
                         return failed(error_code::string_surrogate_high, p);
                     }
@@ -362,108 +331,27 @@ class builder
                     }
                     cp = 0x10000 + ((cp - 0xD800) << 10) + (lo - 0xDC00);
                 }
-                NLOHMANN_VIEW_ENSURE(4)
-                w = put_utf8(w, cp);
+                arena_ensure(4);
+                m_arena_write = put_utf8(m_arena_write, cp);
             }
             else if (NLOHMANN_VIEW_LIKELY(d < 128 && simple_escape[d] != 0))
             {
-                NLOHMANN_VIEW_ENSURE(1)
-                *w++ = simple_escape[d];
+                arena_ensure(1);
+                *m_arena_write++ = simple_escape[d];
             }
             else
             {
                 --p;
                 return failed(error_code::string_escape, p);
             }
-#if NLOHMANN_VIEW_NEON
-            if (p != end && *p == '\\')
+            if (p != m_end && *p == '\\')
             {
                 continue; // consecutive escapes ("\u00e4\u00f6"): no run in between
             }
-            // The first 16 bytes of the run are checked one by one, in predicted branches, and copied
-            // as one block: where the runs between escapes are short, the vector step below would put
-            // its longer dependency chain (load, compare, mask, count, add) on p for each of them,
-            // and be slower than these steps (the scanner of the keys works the same way)
-            {
-                if (end - p >= 16)
-                {
-                    const std::uint8_t* const plain = string_plain();
-                    std::size_t steps = 16;
-#define NLOHMANN_VIEW_STEP(i) if (NLOHMANN_VIEW_LIKELY(plain[p[i]] != 0)) {} else { steps = (i); goto run_found; }
-                    NLOHMANN_VIEW_REPEAT16(NLOHMANN_VIEW_STEP)
-#undef NLOHMANN_VIEW_STEP
-run_found:
-                    NLOHMANN_VIEW_ENSURE(16)
-                    std::memcpy(w, p, 16); // (only the first `steps` bytes are kept)
-                    w += steps;
-                    p += steps;
-                    if (steps < 16)
-                    {
-                        if (*p >= 0x80)
-                        {
-                            // non-ASCII: the UTF-8 check, and the rest of the run
-                            const unsigned char* const r = p;
-                            p = scan_string_run(p, end);
-                            const auto n = static_cast<std::size_t>(p - r);
-                            NLOHMANN_VIEW_ENSURE(n)
-                            std::memcpy(w, r, n);
-                            w += n;
-                        }
-                        continue;
-                    }
-                }
-            }
-#else
-            if (p != end && (*p == '\\' || *p == '"'))
-            {
-                continue; // consecutive escapes ("\u00e4\u00f6"), or the end of the string: no run in between
-            }
-#endif
-#if NLOHMANN_VIEW_VECTOR
-            // the plain bytes up to the next quote, backslash, or control
-            // character are copied as they are scanned, 16 bytes at a time
-            for (;;)
-            {
-                if (NLOHMANN_VIEW_UNLIKELY(end - p < 16))
-                {
-                    const unsigned char* const r = p;
-                    p = scan_string_run(p, end);
-                    const auto n = static_cast<std::size_t>(p - r);
-                    NLOHMANN_VIEW_ENSURE(n)
-                    std::memcpy(w, r, n);
-                    w += n;
-                    break;
-                }
-                NLOHMANN_VIEW_ENSURE(16)
-                const unsigned k = copy_plain_run16(p, w);
-                w += k;
-                p += k;
-                if (k == 16)
-                {
-                    continue;
-                }
-                if (NLOHMANN_VIEW_UNLIKELY(*p >= 0x80))
-                {
-                    // non-ASCII: the UTF-8 check, and the rest of the run
-                    const unsigned char* const r = p;
-                    p = scan_string_run(p, end);
-                    const auto n = static_cast<std::size_t>(p - r);
-                    NLOHMANN_VIEW_ENSURE(n)
-                    std::memcpy(w, r, n);
-                    w += n;
-                }
-                break;
-            }
-#else
             const unsigned char* const r = p;
-            p = scan_string_run(p, end);
-            const auto n = static_cast<std::size_t>(p - r);
-            NLOHMANN_VIEW_ENSURE(n)
-            std::memcpy(w, r, n);
-            w += n;
-#endif
+            p = scan_string_run(p, m_end);
+            arena_run(r, static_cast<std::size_t>(p - r));
         }
-#undef NLOHMANN_VIEW_ENSURE
     }
 
     /// does the float token [s, p) overflow FloatType? (parse() rejects it)
@@ -509,6 +397,14 @@ run_found:
         return m_arena_write != nullptr ? static_cast<std::size_t>(m_arena_write - m_doc.arena.data()) : 0;
     }
 
+    NLOHMANN_VIEW_ALWAYS_INLINE void arena_ensure(std::size_t n)
+    {
+        if (NLOHMANN_VIEW_UNLIKELY(static_cast<std::size_t>(m_arena_end - m_arena_write) < n))
+        {
+            arena_grow(n);
+        }
+    }
+
     NLOHMANN_VIEW_NOINLINE void arena_grow(std::size_t n)
     {
         const std::size_t used = arena_used();
@@ -517,6 +413,25 @@ run_found:
         m_arena_end = m_doc.arena.data() + m_doc.arena.size();
     }
 
+    /// append the run [r, r + n) to the arena; short runs as one fixed-size
+    /// 16-byte move when both sides have the room (no library call)
+    NLOHMANN_VIEW_ALWAYS_INLINE void arena_run(const unsigned char* r, std::size_t n)
+    {
+        if (n <= 16 && m_end - r >= 16)
+        {
+            arena_ensure(16);
+            std::memcpy(m_arena_write, r, 16);
+        }
+        else if (n != 0)
+        {
+            // (an empty run leaves an empty arena unallocated, and memcpy()
+            // must not be passed its null pointer even for zero bytes)
+            arena_ensure(n);
+            std::memcpy(m_arena_write, r, n);
+        }
+        m_arena_write += n;
+    }
+
     /// UTF-8 encoding of cp at w (room for 4 bytes); returns the position after
     /// it. (A returned pointer stays in a register; writing through a
     /// reference to m_arena_write would store and reload it around every byte.)
@@ -1039,11 +954,11 @@ indent_done:
                 ++p;
             }
             const unsigned char* const int_start = p;
-            if (cur() == '0')
+            if (p != e && *p == '0')
             {
                 ++p;
             }
-            else if (NLOHMANN_VIEW_LIKELY(cur() >= '1' && cur() <= '9'))
+            else if (NLOHMANN_VIEW_LIKELY(p != e && *p >= '1' && *p <= '9'))
             {
                 p = skip_digits(p + 1, e);
             }
@@ -1054,7 +969,7 @@ indent_done:
             const auto int_digits = static_cast<std::size_t>(p - int_start);
             std::size_t frac_digits = 0;
             bool is_float = false;
-            if (cur() == '.')
+            if (p != e && *p == '.')
             {
                 ++p;
                 const unsigned char* const f0 = p;
@@ -1067,20 +982,20 @@ indent_done:
                 is_float = true;
             }
             std::int64_t exponent = 0;
-            if ((cur() | 0x20) == 'e')
+            if (p != e && (*p | 0x20) == 'e')
             {
                 ++p;
                 bool exp_negative = false;
-                if (cur() == '+' || cur() == '-')
+                if (p != e && (*p == '+' || *p == '-'))
                 {
                     exp_negative = *p == '-';
                     ++p;
                 }
-                if (NLOHMANN_VIEW_UNLIKELY(!is_digit(cur())))
+                if (NLOHMANN_VIEW_UNLIKELY(p == e || !is_digit(*p)))
                 {
                     return fail(error_code::number_after_exponent);
                 }
-                while (is_digit(cur()))
+                while (p != e && is_digit(*p))
                 {
                     if (exponent < 100000)
                     {
@@ -1142,7 +1057,7 @@ indent_done:
             ++p; // opening quote
             const unsigned char* const s = p;
             p = scan_string_run<Value>(p, e);
-            if (NLOHMANN_VIEW_LIKELY(cur() == '"'))
+            if (NLOHMANN_VIEW_LIKELY(p != e && *p == '"'))
             {
                 push_node(value_t::string, 0, 0, static_cast<std::size_t>(s - b), static_cast<std::uint64_t>(p - s));
                 ++p;

include/nlohmann/detail/view/input.hpp

@@ -10,9 +10,6 @@
 
 #include <algorithm> // max
 #include <cstddef> // size_t
-#ifndef JSON_NO_IO
-    #include <cstdio> // FILE, fread
-#endif
 #include <istream> // istream, streambuf
 #include <string> // basic_string, char_traits, string
 #include <type_traits> // decay, integral_constant, is_array, is_const, is_integral, is_lvalue_reference, is_pointer, is_same, remove_cv, remove_extent, remove_pointer, remove_reference
@@ -157,37 +154,6 @@ inline void append_stream(std::string& buf, std::istream& is)
     is.clear(is.rdstate() | std::ios::eofbit);
 }
 
-/// a pointer to a C stream (never with JSON_NO_IO, which leaves out <cstdio>)
-template<typename T>
-struct is_c_stream
-#ifndef JSON_NO_IO
-    : std::is_same<T, std::FILE*>
-#else
-    : std::false_type
-#endif
-{};
-
-#ifndef JSON_NO_IO
-/// append the rest of a C stream: in blocks with fread, not character by
-/// character (the library's file adapter reads with fgetc);
-/// f is not null
-inline void append_file(std::string& buf, std::FILE* f)
-{
-    for (;;)
-    {
-        const std::size_t used = buf.size();
-        const std::size_t room = (std::max)(buf.capacity() - used, std::size_t{4096});
-        buf.resize(used + room);
-        const std::size_t got = std::fread(&buf[used], 1, room, f);
-        buf.resize(used + got);
-        if (got < room)
-        {
-            break; // end of file, or an error (as fgetc, which returns EOF for both)
-        }
-    }
-}
-#endif
-
 }  // namespace view
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/view/iterator.hpp

@@ -147,21 +147,20 @@ class view_item
 
     view_item(const iterator& it, std::size_t index)
         : m_it(it)
-        , m_position(index)
-    {}
+    {
+        if (!it.is_object_iterator())
+        {
+            m_index = std::to_string(index);
+        }
+    }
 
-    /// the member key, or the element index for arrays (as text made on the
-    /// first call, so that iterating over the values pays nothing for it)
+    /// the member key, or the element index for arrays
     string_view_t key() const
     {
         if (m_it.is_object_iterator())
         {
             return m_it.key();
         }
-        if (m_index.empty())
-        {
-            m_index = std::to_string(m_position);
-        }
         return string_view_t(m_index.data(), m_index.size());
     }
 
@@ -184,8 +183,7 @@ class view_item
 
   private:
     iterator m_it;
-    std::size_t m_position; ///< the index of an array element
-    mutable std::string m_index{}; ///< the text of m_position, once key() was called // NOLINT(readability-redundant-member-init)
+    std::string m_index{}; // NOLINT(readability-redundant-member-init)
 };
 
 /// the range returned by basic_json_view::items()

include/nlohmann/detail/view/lookup.hpp

@@ -166,10 +166,6 @@ const node* element_at(const document_data& d, const node* array, std::size_t id
     {
         return e + idx; // a growable block: one link per element
     }
-    if (array->next == array->len + 1u && (!nav::editable() || (array->flags & node_flags::moved) == 0))
-    {
-        return e + idx; // no element has a subtree: the elements are the nodes after the array
-    }
     for (std::size_t i = 0; i < idx; ++i)
     {
         e = document_data::after(e);
@@ -185,10 +181,6 @@ const node* last_child(const document_data& d, const node* container) noexcept
     const std::size_t value_offset = container->kind == static_cast<std::uint8_t>(value_t::object) ? 1 : 0;
     const node* const end = navigation<Editable>::end(d, container);
     const node* last = navigation<Editable>::first(d, container);
-    if (value_offset == 0 && container->next == container->len + 1u && (!navigation<Editable>::editable() || (container->flags & node_flags::moved) == 0))
-    {
-        return last + (container->len - 1u); // an array without subtrees: the elements are the nodes after it
-    }
     for (const node* c = document_data::after(last + value_offset); c != end; c = document_data::after(c + value_offset))
     {
         last = c;

include/nlohmann/detail/view/materialize.hpp

@@ -8,7 +8,7 @@
 
 #pragma once
 
-#include <array> // array
+#include <algorithm> // max
 #include <cstddef> // size_t
 #include <cstdint> // int64_t, uint8_t
 #include <string> // string
@@ -44,9 +44,8 @@ BasicJsonType materialize(const document_data& d, const node* n)
     using nav = navigation<Editable>;
 
     // the open containers: their next element (or key of the next member),
-    // their end, and whether they are objects; for the first 16 levels on the
-    // stack, else sized once from the document's deepest nesting (for a
-    // subtree an upper bound)
+    // their end, and whether they are objects; sized once from the
+    // document's deepest nesting (for a subtree an upper bound)
     struct frame
     {
         const node* pos;
@@ -54,43 +53,10 @@ BasicJsonType materialize(const document_data& d, const node* n)
         bool object;
     };
 
-    // a scalar needs neither the handler nor the stack of open containers
-    switch (static_cast<value_t>(n->kind))
-    {
-        case value_t::string:
-            return BasicJsonType(string_t(d.str(*n), n->len));
-        case value_t::number_integer:
-            return BasicJsonType(static_cast<typename BasicJsonType::number_integer_t>(static_cast<std::int64_t>(integer_bits(*n))));
-        case value_t::number_unsigned:
-            return BasicJsonType(static_cast<typename BasicJsonType::number_unsigned_t>(integer_bits(*n)));
-        case value_t::number_float:
-            return BasicJsonType(float_value<typename BasicJsonType::number_float_t>(d, *n));
-        case value_t::boolean:
-            return BasicJsonType((n->flags & node_flags::is_true) != 0);
-        case value_t::null:
-            return BasicJsonType(nullptr);
-        case value_t::object:
-        case value_t::array:
-        case value_t::binary:
-        case value_t::discarded:
-        default:
-            break;
-    }
-
     BasicJsonType result;
     sax_t sax(result, true);
     const string_t no_token{};
-    // (shallow subtrees on the stack: a call for a small value then allocates only for the value)
-    std::array<frame, 16> shallow; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): filled as containers open
-    std::vector<frame> deep{};
-    frame* open = shallow.data();
-    std::size_t capacity = shallow.size();
-    if (d.max_depth > capacity)
-    {
-        deep.resize(d.max_depth);
-        open = deep.data();
-        capacity = deep.size();
-    }
+    std::vector<frame> open((std::max)(d.max_depth, std::size_t{1}));
     std::size_t depth = 0;
     for (;;)
     {
@@ -110,13 +76,9 @@ BasicJsonType materialize(const document_data& d, const node* n)
                 {
                     sax.start_array(n->len);
                 }
-                if (NLOHMANN_VIEW_UNLIKELY(depth == capacity))
+                if (NLOHMANN_VIEW_UNLIKELY(depth == open.size()))
                 {
-                    // (deeper than the recorded nesting, e.g. after edits)
-                    deep.assign(open, open + depth);
-                    deep.resize(depth * 2);
-                    open = deep.data();
-                    capacity = deep.size();
+                    open.resize(depth * 2); // (deeper than the recorded nesting, e.g. after edits)
                 }
                 open[depth++] = frame{nav::first(d, n), nav::end(d, n), object};
                 break;

include/nlohmann/detail/view/object_index.hpp

@@ -47,96 +47,27 @@ constexpr std::size_t index_max_displacement = 64;
 static_assert(document_data::index_min_members >= 2 * index_max_displacement,
               "a table must be much larger than the probe window of a lookup");
 
-/// hash of a key: its bytes, eight at a time (in a fixed byte order), where the
-/// last word may overlap the one before (so that no loop over single bytes is
-/// needed); a key of fewer than eight bytes is read as two overlapping words of
-/// four or two bytes (in the native byte order: the hash is not stored, and the
-/// same on both sides of a lookup)
+/// hash of a key: its bytes, eight at a time, in a fixed byte order
 inline std::uint64_t key_hash(const char* s, std::size_t n) noexcept
 {
     std::uint64_t h = 0x9E3779B97F4A7C15u * (n + 1);
     const auto* p = reinterpret_cast<const unsigned char*>(s); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    while (n >= 8)
+    {
+        h = (h ^ read_eight_bytes(p)) * 0xBF58476D1CE4E5B9u;
+        h ^= h >> 29u;
+        p += 8;
+        n -= 8;
+    }
     std::uint64_t w = 0;
-    if (n >= 8)
+    for (std::size_t i = 0; i < n; ++i)
     {
-        const unsigned char* const last = p + n - 8;
-        while (p < last)
-        {
-            h = (h ^ read_eight_bytes(p)) * 0xBF58476D1CE4E5B9u;
-            h ^= h >> 29u;
-            p += 8;
-        }
-        w = read_eight_bytes(last);
+        w |= static_cast<std::uint64_t>(p[i]) << (8u * i);
     }
-    else if (n >= 4)
-    {
-        std::uint32_t head = 0;
-        std::uint32_t tail = 0;
-        std::memcpy(&head, p, 4);
-        std::memcpy(&tail, p + n - 4, 4);
-        w = static_cast<std::uint64_t>(head) | (static_cast<std::uint64_t>(tail) << 32u);
-    }
-    else if (n >= 2)
-    {
-        std::uint16_t head = 0;
-        std::uint16_t tail = 0;
-        std::memcpy(&head, p, 2);
-        std::memcpy(&tail, p + n - 2, 2);
-        w = static_cast<std::uint64_t>(head) | (static_cast<std::uint64_t>(tail) << 16u);
-    }
-    else if (n == 1)
-    {
-        w = p[0];
-    }
-    // (a product only carries bits upwards, and the slot is taken from the low
-    // bits: the high bits of the last word are folded down before the multiplication)
-    h = (h ^ w ^ (w >> 29u)) * 0x94D049BB133111EBu;
+    h = (h ^ w) * 0x94D049BB133111EBu;
     return h ^ (h >> 31u);
 }
 
-/// whether the n <= 16 bytes at a and b are equal, as two overlapping words
-/// (the first and the last 8, 4, or 2 bytes) and without a call
-NLOHMANN_VIEW_ALWAYS_INLINE bool same_short_bytes(const unsigned char* a, const unsigned char* b, std::size_t n) noexcept
-{
-    if (n >= 8)
-    {
-        std::uint64_t x0 = 0;
-        std::uint64_t x1 = 0;
-        std::uint64_t y0 = 0;
-        std::uint64_t y1 = 0;
-        std::memcpy(&x0, a, 8);
-        std::memcpy(&x1, a + n - 8, 8);
-        std::memcpy(&y0, b, 8);
-        std::memcpy(&y1, b + n - 8, 8);
-        return x0 == y0 && x1 == y1;
-    }
-    if (n >= 4)
-    {
-        std::uint32_t x0 = 0;
-        std::uint32_t x1 = 0;
-        std::uint32_t y0 = 0;
-        std::uint32_t y1 = 0;
-        std::memcpy(&x0, a, 4);
-        std::memcpy(&x1, a + n - 4, 4);
-        std::memcpy(&y0, b, 4);
-        std::memcpy(&y1, b + n - 4, 4);
-        return x0 == y0 && x1 == y1;
-    }
-    if (n >= 2)
-    {
-        std::uint16_t x0 = 0;
-        std::uint16_t x1 = 0;
-        std::uint16_t y0 = 0;
-        std::uint16_t y1 = 0;
-        std::memcpy(&x0, a, 2);
-        std::memcpy(&x1, a + n - 2, 2);
-        std::memcpy(&y0, b, 2);
-        std::memcpy(&y1, b + n - 2, 2);
-        return x0 == y0 && x1 == y1;
-    }
-    return n == 0 || *a == *b;
-}
-
 /// build the table of a large object
 inline void build_object_index(document_data& d, node* obj)
 {
@@ -201,27 +132,6 @@ inline const node* find_indexed(const document_data& d, const node* obj, const c
     const document_data::object_index& ix = d.indexes[obj->extra - 1u];
     const std::uint32_t* const table = d.index_slots.data() + ix.start;
     std::size_t slot = conditional_static_cast<std::size_t>(key_hash(key, n)) & ix.mask;
-    const auto* const k_bytes = reinterpret_cast<const unsigned char*>(key); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
-    // (the loop for longer keys comes first, as the code is laid out; it is not the more common case)
-    if (NLOHMANN_VIEW_UNLIKELY(n <= 16))
-    {
-        // (up to 16 bytes, the bytes are compared as two words, without a call)
-        for (std::size_t distance = 0; distance <= index_max_displacement; ++distance)
-        {
-            const std::uint32_t s = table[slot];
-            if (s == 0)
-            {
-                return nullptr;
-            }
-            const node* const k = obj + s;
-            if (k->len == n && same_short_bytes(reinterpret_cast<const unsigned char*>(d.str(*k)), k_bytes, n)) // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
-            {
-                return k;
-            }
-            slot = (slot + 1) & ix.mask;
-        }
-        return nullptr;
-    }
     for (std::size_t distance = 0; distance <= index_max_displacement; ++distance)
     {
         const std::uint32_t s = table[slot];

include/nlohmann/detail/view/simd.hpp

@@ -116,34 +116,6 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* vector_plain_run(const unsigned
     }
     return p;
 }
-
-/*!
-@brief copy 16 bytes from p to w, and find the first quote, backslash,
-control character, or non-ASCII byte among them
-
-The bytes are copied whether or not they are all plain (the caller has room
-for 16 bytes and keeps only the plain ones).
-
-@return the offset of that byte, or 16 if there is none
-*/
-NLOHMANN_VIEW_ALWAYS_INLINE unsigned copy_plain_run16(const unsigned char* p, char* w) noexcept
-{
-#if NLOHMANN_VIEW_NEON
-    const uint8x16_t in = vld1q_u8(p);
-    vst1q_u8(reinterpret_cast<std::uint8_t*>(w), in); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
-    const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))),
-                                        vcltq_s8(vreinterpretq_s8_u8(in), vdupq_n_s8(0x20)));
-    const std::uint64_t bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
-    return bits != 0 ? static_cast<unsigned>(count_trailing_zeros(bits) >> 2u) : 16u;
-#else
-    const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p))); // NOLINT(bugprone-casting-through-void)
-    _mm_storeu_si128(static_cast<__m128i*>(static_cast<void*>(w)), in); // NOLINT(bugprone-casting-through-void)
-    const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
-                                         _mm_cmplt_epi8(in, _mm_set1_epi8(0x20)));
-    const auto bits = static_cast<std::uint64_t>(static_cast<unsigned>(_mm_movemask_epi8(special)));
-    return bits != 0 ? static_cast<unsigned>(count_trailing_zeros(bits)) : 16u;
-#endif
-}
 #endif
 
 #if NLOHMANN_VIEW_SSSE3_DISPATCH

include/nlohmann/json.hpp

@@ -6878,6 +6878,72 @@ public:
     /// @name JSON Patch functions
     /// @{
 
+  private:
+    /// the members of an operation of a JSON patch that are of interest
+    struct patch_members
+    {
+        basic_json* op = nullptr;
+        basic_json* path = nullptr;
+        basic_json* value = nullptr;
+        basic_json* from = nullptr;
+    };
+
+    /// @brief find the members "op", "path", "value", and "from" of the object @a val in one pass
+    static patch_members find_patch_members(const basic_json& val, std::true_type /*key_type is string_t*/)
+    {
+        patch_members members;
+        for (auto& member : *val.m_data.m_value.object)
+        {
+            const string_t& key = member.first;
+            switch (key.size())
+            {
+                case 2:
+                    if (key == "op")
+                    {
+                        members.op = &member.second;
+                    }
+                    break;
+                case 4:
+                    if (key == "path")
+                    {
+                        members.path = &member.second;
+                    }
+                    else if (key == "from")
+                    {
+                        members.from = &member.second;
+                    }
+                    break;
+                case 5:
+                    if (key == "value")
+                    {
+                        members.value = &member.second;
+                    }
+                    break;
+                default:
+                    break;
+            }
+        }
+        return members;
+    }
+
+    /// @brief find the members by lookup for key types other than string_t
+    static patch_members find_patch_members(const basic_json& val, std::false_type /*key_type is not string_t*/)
+    {
+        const auto find_member = [&val](const char* name) -> basic_json *
+        {
+            const auto it = val.m_data.m_value.object->find(string_t(name));
+            return it != val.m_data.m_value.object->end() ? &it->second : nullptr;
+        };
+
+        patch_members members;
+        members.op = find_member("op");
+        members.path = find_member("path");
+        members.value = find_member("value");
+        members.from = find_member("from");
+        return members;
+    }
+
+  public:
     /// @brief applies a JSON patch in-place without copying the object
     /// @sa https://json.nlohmann.me/api/basic_json/patch/
     void patch_inplace(const basic_json& json_patch)
@@ -7051,18 +7117,18 @@ public:
         // a diff creates them: apply the operation and return true; return
         // false, with nothing changed, for all others
         string_t token;
-        const string_t value_key = "value";
-        const auto try_plain = [&result, &token, &value_key](patch_operations operation, const string_t& path, const basic_json & val)
+        typename json_pointer::template plain_steps<basic_json> steps;
+        const auto try_plain = [&result, &token, &steps](patch_operations operation, const string_t& path, const patch_members & members, const basic_json & val)
         {
-            if (path.empty() || path.find_first_of('~') != string_t::npos)
+            if (path.empty())
             {
                 return false;
             }
 
             // a missing "value" is reported below
-            const auto value_it = val.m_data.m_value.object->find(value_key);
-            const basic_json& value = value_it != val.m_data.m_value.object->end() ? value_it->second : val;
-            if (operation != patch_operations::remove && value_it == val.m_data.m_value.object->end())
+            const basic_json* const value_ptr = members.value;
+            const basic_json& value = value_ptr != nullptr ? *value_ptr : val;
+            if (operation != patch_operations::remove && value_ptr == nullptr)
             {
                 return false;
             }
@@ -7071,7 +7137,7 @@ public:
             {
                 case patch_operations::replace:
                 {
-                    basic_json* const target = json_pointer::resolve_plain(&result, path, path.size(), token);
+                    basic_json* const target = json_pointer::resolve_plain(&result, path, path.size(), token, steps);
                     if (target == nullptr)
                     {
                         return false;
@@ -7082,7 +7148,7 @@ public:
 
                 case patch_operations::test:
                 {
-                    const basic_json* const target = json_pointer::resolve_plain(&result, path, path.size(), token);
+                    const basic_json* const target = json_pointer::resolve_plain(&result, path, path.size(), token, steps);
                     // a failing test is reported below
                     return target != nullptr && *target == value;
                 }
@@ -7102,13 +7168,17 @@ public:
                     }
                     --slash;
 
-                    basic_json* const parent = json_pointer::resolve_plain(&result, path, slash, token);
+                    basic_json* const parent = json_pointer::resolve_plain(&result, path, slash, token, steps);
                     if (parent == nullptr)
                     {
                         return false;
                     }
                     token.clear();
                     token.append(path.data() + slash + 1, path.size() - slash - 1);
+                    if (token.find_first_of('~') != string_t::npos)
+                    {
+                        return false;
+                    }
 
                     if (operation == patch_operations::add)
                     {
@@ -7164,31 +7234,32 @@ public:
             }
         };
 
+        // the name of the first member to check
+        const string_t op_member = "op";
+
         // iterate and apply the operations
         for (const auto& val : json_patch)
         {
             // wrapper to get a value for an operation
-            const auto get_value = [&val](const string_t& op,
-                                          const string_t& member,
+            const auto get_value = [&val](basic_json * found,
+                                          const string_t& op,
+                                          const char* member,
                                           bool string_type) -> basic_json &
             {
-                // find value
-                auto it = val.m_data.m_value.object->find(member);
-
                 // check if the desired value is present
-                if (JSON_HEDLEY_UNLIKELY(it == val.m_data.m_value.object->end()))
+                if (JSON_HEDLEY_UNLIKELY(found == nullptr))
                 {
-                    detail::throw_patch_missing_member(op, member, false, val);
+                    detail::throw_patch_missing_member(op, string_t(member), false, val);
                 }
 
                 // check if the result is of type string
-                if (JSON_HEDLEY_UNLIKELY(string_type && !it->second.is_string()))
+                if (JSON_HEDLEY_UNLIKELY(string_type && !found->is_string()))
                 {
-                    detail::throw_patch_missing_member(op, member, true, val);
+                    detail::throw_patch_missing_member(op, string_t(member), true, val);
                 }
 
                 // no error: return value
-                return it->second;
+                return *found;
             };
 
             // type check: every element of the array must be an object
@@ -7197,26 +7268,30 @@ public:
                 detail::throw_patch_not_an_array(val);
             }
 
+            const patch_members members = find_patch_members(val, std::is_same<typename object_t::key_type, string_t> {});
+
             // collect mandatory members
-            const string_t& op = *get_value("op", "op", true).m_data.m_value.string;
-            const string_t& path = *get_value(op, "path", true).m_data.m_value.string;
+            const string_t& op = *get_value(members.op, op_member, "op", true).m_data.m_value.string;
+            const string_t& path = *get_value(members.path, op, "path", true).m_data.m_value.string;
             const patch_operations operation = get_op(op);
 
             // the usual operations on a plain pointer are applied without
             // building the pointer's reference tokens; anything else (and
             // every error) is handled below
-            if (try_plain(operation, path, val))
+            if (try_plain(operation, path, members, val))
             {
                 continue;
             }
 
+            // the general operations may change any container
+            steps.reset();
             json_pointer ptr(path);
 
             switch (operation)
             {
                 case patch_operations::add:
                 {
-                    operation_add(ptr, get_value("add", "value", false));
+                    operation_add(ptr, get_value(members.value, "add", "value", false));
                     break;
                 }
 
@@ -7229,13 +7304,13 @@ public:
                 case patch_operations::replace:
                 {
                     // the "path" location must exist - use at()
-                    result.at(ptr) = get_value("replace", "value", false);
+                    result.at(ptr) = get_value(members.value, "replace", "value", false);
                     break;
                 }
 
                 case patch_operations::move:
                 {
-                    const string_t& from_path = *get_value("move", "from", true).m_data.m_value.string;
+                    const string_t& from_path = *get_value(members.from, "move", "from", true).m_data.m_value.string;
                     json_pointer from_ptr(from_path);
 
                     if (JSON_HEDLEY_UNLIKELY(is_proper_prefix(from_ptr, ptr)))
@@ -7258,7 +7333,7 @@ public:
 
                 case patch_operations::copy:
                 {
-                    const string_t& from_path = *get_value("copy", "from", true).m_data.m_value.string;
+                    const string_t& from_path = *get_value(members.from, "copy", "from", true).m_data.m_value.string;
                     const json_pointer from_ptr(from_path);
 
                     // The copy is functionally identical to an "add"
@@ -7276,7 +7351,7 @@ public:
                     {
                         // check if "value" matches the one at "path"
                         // the "path" location must exist - use at()
-                        success = (result.at(ptr) == get_value("test", "value", false));
+                        success = (result.at(ptr) == get_value(members.value, "test", "value", false));
                     }
                     JSON_INTERNAL_CATCH (out_of_range&)
                     {
@@ -7368,13 +7443,18 @@ public:
     /// @brief append an operation @a op for @a path to @a result, with @a value if it is not null
     static void diff_operation(basic_json& result, const char* op, const string_t& path, const basic_json* value)
     {
+        // the keys are distinct and in the order of std::map; the members are
+        // added without looking them up
         basic_json entry(value_t::object);
-        entry["op"] = op;
-        entry["path"] = path;
+        auto& members = *entry.m_data.m_value.object;
+        typename object_t::iterator hint = members.end();
+        json_pointer::add_flattened(members, hint, string_t("op"), string_t(op), detail::priority_tag<2> {});
+        json_pointer::add_flattened(members, hint, string_t("path"), path, detail::priority_tag<2> {});
         if (value != nullptr)
         {
-            entry["value"] = *value;
+            json_pointer::add_flattened(members, hint, string_t("value"), *value, detail::priority_tag<2> {});
         }
+        entry.set_parents();
         result.push_back(std::move(entry));
     }
 
@@ -7396,6 +7476,50 @@ public:
         diff_operation(result, "add", path, &value);
     }
 
+    /// @brief the values in the target of the members of a source object, for the
+    ///        objects of up to 16 members without allocating
+    ///
+    /// reserve() must be called with the number of values that are added.
+    class diff_target_values
+    {
+      public:
+        diff_target_values() = default;
+        diff_target_values(const diff_target_values&) = delete;
+        diff_target_values& operator=(const diff_target_values&) = delete;
+        ~diff_target_values() = default;
+
+        void reserve(const std::size_t n)
+        {
+            if (n > inline_size)
+            {
+                large.resize(n);
+                items = large.data();
+            }
+        }
+
+        void push_back(const basic_json* value)
+        {
+            items[count++] = value;
+        }
+
+        std::size_t size() const noexcept
+        {
+            return count;
+        }
+
+        const basic_json* operator[](const std::size_t i) const noexcept
+        {
+            return items[i];
+        }
+
+      private:
+        static constexpr std::size_t inline_size = 16;
+        std::size_t count = 0;
+        const basic_json** items = inline_items;
+        std::vector<const basic_json*> large{}; // NOLINT(readability-redundant-member-init)
+        const basic_json* inline_items[inline_size]; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init)
+    };
+
     /// @brief append "/" and the decimal representation of @a index to @a path
     static void diff_append_index(string_t& path, std::size_t index)
     {
@@ -7476,8 +7600,9 @@ public:
     operations that remove every member of @a source and add every member of
     @a target to @a result, and returns false.
     */
+    template<typename TargetValues>
     static bool diff_object_keys(basic_json& result, const basic_json& source, const basic_json& target,
-                                 const string_t& path, std::vector<const basic_json*>& target_values,
+                                 const string_t& path, TargetValues& target_values,
                                  std::vector<const_iterator>& added)
     {
         // first pass: one lookup per source key
@@ -7691,7 +7816,7 @@ public:
 
             case value_t::object:
             {
-                std::vector<const basic_json*> target_values;
+                diff_target_values target_values;
                 std::vector<const_iterator> added;
                 if (diff_object_keys(result, source, target, path, target_values, added))
                 {

include/nlohmann/json_view.hpp

@@ -295,7 +295,7 @@ class basic_json_view
             }
             detail::view::throw_type_error(305, "cannot use operator[] with a numeric argument with ", type_name());
         }
-        return idx < m_node->len ? element(idx) : basic_json_view();
+        return idx < m_node->len ? basic_json_view(m_doc, navigation::value(detail::view::element_at<Editable>(*m_doc, m_node, idx))) : basic_json_view();
     }
 
     /// any other integer type (int, unsigned, long, std::int64_t, ...; a
@@ -358,7 +358,7 @@ class basic_json_view
         {
             detail::view::throw_out_of_range(401, detail::concat("array index ", std::to_string(idx), " is out of range"));
         }
-        return element(idx);
+        return basic_json_view(m_doc, navigation::value(detail::view::element_at<Editable>(*m_doc, m_node, idx)));
     }
 
     /// any other integer type, see operator[]; negative values are out of
@@ -392,13 +392,7 @@ class basic_json_view
 
     string_t value(string_view_t key, const char* default_value) const
     {
-        if (NLOHMANN_VIEW_UNLIKELY(!is_object()))
-        {
-            detail::view::throw_type_error(306, "cannot use value() with ", type_name());
-        }
-        // (the default is made only if there is no such member)
-        const basic_json_view r = lookup(key);
-        return r.is_discarded() ? string_t(default_value) : r.template get<string_t>();
+        return value(key, string_t(default_value));
     }
 
     /// the value a JSON pointer refers to converted to T, or the default
@@ -417,12 +411,7 @@ class basic_json_view
 
     string_t value(const json_pointer& ptr, const char* default_value) const
     {
-        if (NLOHMANN_VIEW_UNLIKELY(!is_structured()))
-        {
-            detail::view::throw_type_error(306, "cannot use value() with ", type_name());
-        }
-        const basic_json_view r = detail::view::resolve_pointer(*this, detail::json_pointer_access::reference_tokens(ptr), detail::view::pointer_mode::value);
-        return r.is_discarded() ? string_t(default_value) : r.template get<string_t>();
+        return value(ptr, string_t(default_value));
     }
 
     /// the first element or member value; a primitive value itself. Throws
@@ -444,8 +433,7 @@ class basic_json_view
     {
         if (is_structured() && m_node->len != 0)
         {
-            return unedited() ? basic_json_view(m_doc, detail::view::last_child<false>(*m_doc, m_node) + (is_object() ? 1 : 0))
-                   : basic_json_view(m_doc, navigation::value(detail::view::last_child<Editable>(*m_doc, m_node) + (is_object() ? 1 : 0)));
+            return basic_json_view(m_doc, navigation::value(detail::view::last_child<Editable>(*m_doc, m_node) + (is_object() ? 1 : 0)));
         }
         return front();
     }
@@ -462,8 +450,7 @@ class basic_json_view
         {
             return end();
         }
-        const node* const k = unedited() ? detail::view::find_member<false>(*m_doc, m_node, key.data(), key.size())
-                              : detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size());
+        const node* const k = detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size());
         return k != nullptr ? iterator(m_doc, k, true) : end();
     }
 
@@ -480,8 +467,7 @@ class basic_json_view
     /// whether this is an object with a member with this key
     bool contains(string_view_t key) const
     {
-        return is_object() && (unedited() ? detail::view::find_member<false>(*m_doc, m_node, key.data(), key.size()) != nullptr
-                               : detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size()) != nullptr);
+        return is_object() && detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size()) != nullptr;
     }
 
     bool contains(const char* key) const
@@ -641,14 +627,7 @@ class basic_json_view
         // the compact writer keeps 64 bytes of slack, so that it does not grow
         // the buffer just before the end
         const std::size_t estimate = source_extent() + (style.pretty ? source_extent() / 2 : 0) + 160;
-        if (unedited())
-        {
-            detail::view::view_serializer<BasicJsonType, false>(*m_doc, out, estimate, style).dump(m_node);
-        }
-        else
-        {
-            detail::view::view_serializer<BasicJsonType, Editable>(*m_doc, out, estimate, style).dump(m_node);
-        }
+        detail::view::view_serializer<BasicJsonType, Editable>(*m_doc, out, estimate, style).dump(m_node);
         return out;
     }
 
@@ -728,7 +707,7 @@ class basic_json_view
         {
             return BasicJsonType(value_t::discarded);
         }
-        return unedited() ? detail::view::materialize<BasicJsonType, false>(*m_doc, m_node) : detail::view::materialize<BasicJsonType, Editable>(*m_doc, m_node);
+        return detail::view::materialize<BasicJsonType, Editable>(*m_doc, m_node);
     }
 
     /// byte offset of this value in the source text (for strings: of the
@@ -806,32 +785,10 @@ class basic_json_view
     /// (object required)
     NLOHMANN_VIEW_ALWAYS_INLINE basic_json_view lookup(string_view_t key) const noexcept
     {
-        if (unedited())
-        {
-            const node* const k = detail::view::find_member<false>(*m_doc, m_node, key.data(), key.size());
-            return k != nullptr ? basic_json_view(m_doc, k + 1) : basic_json_view();
-        }
         const node* const k = detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size());
         return k != nullptr ? basic_json_view(m_doc, navigation::value(k + 1)) : basic_json_view();
     }
 
-    /// whether the document has not been edited yet: until the first edit, its index is walked like that of a
-    /// read-only document (nothing is moved or linked), which is cheaper
-    NLOHMANN_VIEW_ALWAYS_INLINE bool unedited() const noexcept
-    {
-        return !navigation::editable() || m_doc->edits == nullptr;
-    }
-
-    /// the element of an array at an index below its size
-    NLOHMANN_VIEW_ALWAYS_INLINE basic_json_view element(size_type idx) const
-    {
-        if (unedited())
-        {
-            return basic_json_view(m_doc, detail::view::element_at<false>(*m_doc, m_node, idx));
-        }
-        return basic_json_view(m_doc, navigation::value(detail::view::element_at<Editable>(*m_doc, m_node, idx)));
-    }
-
     // --- get() dispatch ---
 
     bool get_impl(detail::view::value_tag<bool> /*unused*/, detail::priority_tag<2> /*unused*/) const
@@ -1571,8 +1528,7 @@ class basic_json_document
         // NOLINTBEGIN(readability-avoid-nested-conditional-operator): a constant expression of C++11
         append_input_impl(buf, std::forward<T>(input), std::integral_constant < int, detail::is_contiguous_byte_container<D>::value ? 0
                           : std::is_base_of<std::istream, D>::value ? 1
-                          : detail::view::is_adapter_input<D>::value ? 2
-                          : detail::view::is_c_stream<D>::value ? 4 : 3 > {});
+                          : detail::view::is_adapter_input<D>::value ? 2 : 3 > {});
         // NOLINTEND(readability-avoid-nested-conditional-operator)
     }
 
@@ -1594,19 +1550,6 @@ class basic_json_document
         detail::view::append_adapter(buf, std::move(input.ia));
     }
 
-#ifndef JSON_NO_IO
-    static void append_input_impl(std::string& buf, std::FILE* file, std::integral_constant<int, 4> /*C stream*/)
-    {
-        if (file == nullptr)
-        {
-            // (as before: the library's adapter decides what a null stream yields)
-            detail::view::append_adapter(buf, detail::input_adapter(file));
-            return;
-        }
-        detail::view::append_file(buf, file);
-    }
-#endif
-
     template<typename T>
     static void append_input_impl(std::string& buf, T&& input, std::integral_constant<int, 3> /*other*/)
     {

single_include/nlohmann/json.hpp

@@ -22357,7 +22357,7 @@ NLOHMANN_JSON_NAMESPACE_END
 #include <cstddef> // size_t
 #include <cstdint> // uint64_t
 #include <cstdlib> // strtoull
-#include <cstring> // memcmp, memcpy
+#include <cstring> // memchr, memcmp, memcpy
 #ifndef JSON_NO_IO
     #include <iosfwd> // ostream
 #endif  // JSON_NO_IO
@@ -22653,6 +22653,12 @@ class json_pointer
         exceeds_size_type  ///< @a s converts to an integer that exceeds size_type
     };
 
+    /// whether a reference token is "-" (a plain comparison with a string literal is not always inlined)
+    static bool is_dash(const string_t& s) noexcept
+    {
+        return s.size() == 1 && s[0] == '-';
+    }
+
     /*!
     @param[in] s    reference token to be converted into an array index
     @param[out] idx the integer representation of @a s if @ref array_index_status::ok
@@ -22678,7 +22684,7 @@ class json_pointer
         // error condition (cf. RFC 6901, Sect. 4); this also covers single-
         // character tokens, so "/x" and "/xy" fail alike; "-" and the empty
         // token are left to the conversion below and are reported as unresolved
-        if (JSON_HEDLEY_UNLIKELY(!s.empty() && s != "-" && !(s[0] >= '0' && s[0] <= '9')))
+        if (JSON_HEDLEY_UNLIKELY(!s.empty() && !is_dash(s) && !(s[0] >= '0' && s[0] <= '9')))
         {
             return array_index_status::not_a_number;
         }
@@ -22825,9 +22831,40 @@ class json_pointer
         return pos == size;
     }
 
+    /// reserve room for @a n elements of an array type that has reserve()
+    template<typename ArrayType>
+    static auto reserve_elements(ArrayType& array, const std::size_t n, detail::priority_tag<1> /*unused*/)
+    -> decltype(array.reserve(n), void())
+    {
+        array.reserve(n);
+    }
+
+    template<typename ArrayType>
+    static void reserve_elements(ArrayType& /*array*/, const std::size_t /*n*/, detail::priority_tag<0> /*unused*/)
+    {}
+
     /// @brief object member access with a key that is only copied if it is inserted
+    ///
+    /// Objects that can find the position of a key and insert there
+    /// (std::map) search once, others look the key up and add it if it is missing.
     template<typename BasicJsonType>
-    static BasicJsonType& object_member(BasicJsonType& object, const string_t& key)
+    static auto object_member_impl(BasicJsonType& object, const string_t& key, detail::priority_tag<1> /*unused*/)
+    -> decltype(object.m_data.m_value.object->emplace_hint(object.m_data.m_value.object->lower_bound(key), key, nullptr), std::declval<BasicJsonType&>())
+    {
+        auto& members = *object.m_data.m_value.object;
+        auto it = members.lower_bound(key);
+        if (it != members.end() && !members.key_comp()(key, it->first))
+        {
+            return it->second;
+        }
+
+        const auto old_capacity = object.container_capacity();
+        it = members.emplace_hint(it, key, nullptr);
+        return object.set_parent_after_insert(it->second, old_capacity);
+    }
+
+    template<typename BasicJsonType>
+    static BasicJsonType& object_member_impl(BasicJsonType& object, const string_t& key, detail::priority_tag<0> /*unused*/)
     {
         auto& members = *object.m_data.m_value.object;
         const auto it = members.find(key);
@@ -22838,6 +22875,12 @@ class json_pointer
         return object.operator[](key);
     }
 
+    template<typename BasicJsonType>
+    static BasicJsonType& object_member(BasicJsonType& object, const string_t& key)
+    {
+        return object_member_impl(object, key, detail::priority_tag<1> {});
+    }
+
   JSON_PRIVATE_UNLESS_TESTED:
     json_pointer top() const
     {
@@ -23070,48 +23113,103 @@ class json_pointer
         }
     }
 
+    /*!
+    @brief the values along the pointer last resolved by @ref resolve_plain
+
+    A patch from @ref basic_json::diff lists its operations in document order,
+    so consecutive pointers share most of their reference tokens; the values
+    along the previous pointer are kept to resume from the common prefix.
+    `steps[k]` is the value after the first `k` reference tokens together with
+    the length of the prefix of `*path` that holds them. A value stays valid as
+    long as no operation changes its container: callers keep only values up to
+    the parent of the pointer they modify, or call `reset()`.
+    */
+    template<typename BasicJsonType>
+    struct plain_steps
+    {
+        const string_t* path = nullptr;
+        std::vector<std::pair<std::size_t, BasicJsonType*>> steps{};
+
+        void reset() noexcept
+        {
+            path = nullptr;
+            steps.clear();
+        }
+    };
+
     /*!
     @brief resolve a plain JSON pointer without building its reference tokens
 
-    @param[in] ptr     the value the pointer starts at
+    @param[in] root    the value the pointer starts at
     @param[in] path    a JSON pointer string
     @param[in] length  the number of leading bytes of @a path to resolve; 0 or
                        the position of a slash
     @param[in,out] token  a string to hold the reference tokens, to reuse its storage
+    @param[in,out] cache  the values along the previously resolved pointer;
+                          @a path must outlive the next call
 
     @return the pointed to value, or `nullptr` if the pointer does not denote
-            an existing value, or does so in a way that is not plain: a
-            reference token with an escape, an array index that is malformed or
-            out of range, or a "-". No exception is thrown for these; callers
-            use @ref json_pointer instead, which handles them.
+            an existing value, or does so in a way that is not plain: an array
+            index that is malformed or out of range, or a "-", or a reference
+            token with an escape. No exception is
+            thrown for these; callers use @ref json_pointer instead, which
+            handles them.
     */
     template<typename BasicJsonType>
-    static BasicJsonType* resolve_plain(BasicJsonType* ptr, const string_t& path, const std::size_t length, string_t& token)
+    static BasicJsonType* resolve_plain(BasicJsonType* root, const string_t& path, const std::size_t length, string_t& token, plain_steps<BasicJsonType>& cache)
     {
-        for (std::size_t pos = 0; pos < length;)
+        auto& steps = cache.steps;
+
+        // resume from the deepest step that is also a prefix of this path
+        std::size_t depth = 1;
+        if (cache.path != nullptr && !steps.empty() && steps[0].second == root)
+        {
+            const string_t& previous = *cache.path;
+            for (depth = steps.size(); depth > 1; --depth)
+            {
+                // a step ends at a token boundary of the previous path
+                const std::size_t prefix = steps[depth - 1].first;
+                if (prefix <= length && (prefix == length || path[prefix] == '/') && std::memcmp(path.data(), previous.data(), prefix) == 0)
+                {
+                    break;
+                }
+            }
+            steps.resize(depth);
+        }
+        else
+        {
+            steps.assign(1, std::make_pair(std::size_t{0}, root));
+        }
+        cache.path = &path;
+
+        BasicJsonType* ptr = steps[depth - 1].second;
+        for (std::size_t pos = steps[depth - 1].first; pos < length;)
         {
             if (JSON_HEDLEY_UNLIKELY(path[pos] != '/'))
             {
                 return nullptr;
             }
 
-            // the reference token between the slash at pos and the next one
-            std::size_t end = path.find_first_of('/', pos + 1);
-            if (end == string_t::npos || end > length)
+            // the reference token between the slash at pos and the next one,
+            // which must not have an escape
+            const char* const begin = path.data() + pos + 1;
+            const char* const limit = path.data() + length;
+            const char* end = begin;
+            while (end < limit && *end != '/')
             {
-                end = length;
-            }
-            token.clear();
-            token.append(path.data() + pos + 1, end - pos - 1);
-            if (JSON_HEDLEY_UNLIKELY(token.find_first_of('~') != string_t::npos))
-            {
-                return nullptr;
+                if (JSON_HEDLEY_UNLIKELY(*end == '~'))
+                {
+                    return nullptr;
+                }
+                ++end;
             }
 
             switch (ptr->type())
             {
                 case detail::value_t::object:
                 {
+                    token.clear();
+                    token.append(begin, static_cast<std::size_t>(end - begin));
                     const auto it = ptr->m_data.m_value.object->find(token);
                     if (JSON_HEDLEY_UNLIKELY(it == ptr->m_data.m_value.object->end()))
                     {
@@ -23123,8 +23221,24 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    typename BasicJsonType::size_type idx{};
-                    if (JSON_HEDLEY_UNLIKELY(parse_array_index<BasicJsonType>(token, idx) != array_index_status::ok || idx >= ptr->m_data.m_value.array->size()))
+                    // an index of up to 18 digits without a leading zero fits into size_type
+                    // (9 digits for a 32-bit size_type); everything else is left to json_pointer
+                    constexpr std::size_t max_digits = sizeof(typename BasicJsonType::size_type) >= 8 ? 18 : 9;
+                    const std::size_t digits = static_cast<std::size_t>(end - begin);
+                    if (JSON_HEDLEY_UNLIKELY(digits == 0 || digits > max_digits || (digits > 1 && *begin == '0')))
+                    {
+                        return nullptr;
+                    }
+                    typename BasicJsonType::size_type idx = 0;
+                    for (const char* c = begin; c != end; ++c)
+                    {
+                        if (JSON_HEDLEY_UNLIKELY(*c < '0' || *c > '9'))
+                        {
+                            return nullptr;
+                        }
+                        idx = static_cast<typename BasicJsonType::size_type>((idx * 10) + static_cast<typename BasicJsonType::size_type>(*c - '0'));
+                    }
+                    if (JSON_HEDLEY_UNLIKELY(idx >= ptr->m_data.m_value.array->size()))
                     {
                         return nullptr;
                     }
@@ -23143,7 +23257,8 @@ class json_pointer
                 default:
                     return nullptr;
             }
-            pos = end;
+            pos = static_cast<std::size_t>(end - path.data());
+            steps.emplace_back(pos, ptr);
         }
 
         return ptr;
@@ -23257,7 +23372,7 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    if (JSON_HEDLEY_UNLIKELY(is_dash(reference_token)))
                     {
                         // "-" always fails the range check
                         JSON_THROW(detail::out_of_range::create(detail::exception_id::pointer_past_the_end_index, detail::concat(
@@ -23328,7 +23443,7 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    if (JSON_HEDLEY_UNLIKELY(is_dash(reference_token)))
                     {
                         // "-" cannot be used for const access
                         JSON_THROW(detail::out_of_range::create(detail::exception_id::pointer_past_the_end_index, detail::concat("array index '-' (", std::to_string(ptr->m_data.m_value.array->size()), ") is out of range"), ptr));
@@ -23390,7 +23505,7 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    if (JSON_HEDLEY_UNLIKELY(is_dash(reference_token)))
                     {
                         // "-" always fails the range check
                         return nullptr;
@@ -23467,7 +23582,7 @@ class json_pointer
 
                 case detail::value_t::array:
                 {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
+                    if (JSON_HEDLEY_UNLIKELY(is_dash(reference_token)))
                     {
                         // "-" always fails the range check
                         return false;
@@ -23626,6 +23741,52 @@ class json_pointer
         obj[key] = std::forward<ValueType>(v);
     }
 
+    /// the number of entries that flattening @a value adds: its primitive
+    /// values and empty containers
+    template<typename BasicJsonType>
+    static std::size_t count_flattened(const BasicJsonType& value)
+    {
+        std::size_t count = 0;
+        std::vector<const BasicJsonType*> pending(1, &value);
+        while (!pending.empty())
+        {
+            const BasicJsonType* const v = pending.back();
+            pending.pop_back();
+            if (v->is_array() && !v->m_data.m_value.array->empty())
+            {
+                for (const auto& element : *v->m_data.m_value.array)
+                {
+                    pending.push_back(&element);
+                }
+            }
+            else if (v->is_object() && !v->m_data.m_value.object->empty())
+            {
+                for (const auto& member : *v->m_data.m_value.object)
+                {
+                    pending.push_back(&member.second);
+                }
+            }
+            else
+            {
+                ++count;
+            }
+        }
+        return count;
+    }
+
+    // Reserve the storage for @a value of objects that have a reserve(), so
+    // that it does not have to be moved while it grows
+    template<typename ObjectType, typename BasicJsonType>
+    static auto reserve_flattened(ObjectType& obj, const BasicJsonType& value, detail::priority_tag<1> /*unused*/)
+    -> decltype(obj.reserve(std::size_t {}), void())
+    {
+        obj.reserve(count_flattened(value));
+    }
+
+    template<typename ObjectType, typename BasicJsonType>
+    static void reserve_flattened(ObjectType& /*obj*/, const BasicJsonType& /*value*/, detail::priority_tag<0> /*unused*/)
+    {}
+
     /// append the decimal representation of @a i to @a out
     static void append_index(string_t& out, std::size_t i)
     {
@@ -23735,6 +23896,7 @@ class json_pointer
             }
         };
 
+        reserve_flattened(object, value, detail::priority_tag<1> {});
         enter(value);
         while (!stack.empty())
         {
@@ -23742,8 +23904,9 @@ class json_pointer
             // frame, which would invalidate a reference to it
             const BasicJsonType* const container = stack.back().container;
 
-            // drop the path of the previous child
-            path.resize(stack.back().path_length);
+            // the path of the previous child is replaced by the path of the
+            // next one; for an array element in one resize
+            const std::size_t path_length = stack.back().path_length;
 
             if (container->is_array())
             {
@@ -23757,8 +23920,20 @@ class json_pointer
 
                 // iterate array and use index as a reference string
                 ++stack.back().index;
-                path.push_back('/');
-                append_index(path, i);
+                std::array<char, 24> digits{};
+                std::size_t pos = digits.size();
+                std::size_t rest = i;
+                do
+                {
+                    digits[--pos] = static_cast<char>('0' + rest % 10);
+                    rest /= 10;
+                }
+                while (rest != 0);
+                const std::size_t count = digits.size() - pos;
+                path.resize(path_length + 1 + count);
+                char* const out = &path[path_length];
+                out[0] = '/';
+                std::memcpy(out + 1, digits.data() + pos, count);
                 enter(array[i]);
             }
             else
@@ -23772,6 +23947,7 @@ class json_pointer
 
                 // iterate object and use keys as reference string
                 ++stack.back().member;
+                path.resize(path_length);
                 path.push_back('/');
                 detail::escape_into(path, it->first);
                 enter(it->second);
@@ -23867,8 +24043,28 @@ class json_pointer
                 {
                     end = key.size();
                 }
+                const std::size_t token_size = end - pos - 1;
+
+                // a token that is a plain index of up to 9 digits, which is
+                // the case for almost all array elements, is not copied
+                std::size_t index = 0;
+                bool plain_index = current->type() == detail::value_t::array && token_size != 0 && token_size <= 9 && (token_size == 1 || data[pos + 1] != '0');
+                for (std::size_t k = pos + 1; plain_index && k < end; ++k)
+                {
+                    plain_index = data[k] >= '0' && data[k] <= '9';
+                    index = (index * 10) + static_cast<std::size_t>(data[k] - '0');
+                }
+                if (plain_index)
+                {
+                    current = &current->operator[](static_cast<typename BasicJsonType::size_type>(index));
+                    values.push_back(current);
+                    ends.push_back(end);
+                    pos = end;
+                    continue;
+                }
+
                 token.clear();
-                token.append(data + pos + 1, end - pos - 1);
+                token.append(data + pos + 1, token_size);
                 if (token.find_first_of('~') != string_t::npos)
                 {
                     detail::unescape(token);
@@ -23878,10 +24074,13 @@ class json_pointer
                 {
                     case detail::value_t::null:
                     {
-                        if (arrays.contains(data, pos))
+                        // a first child 0 makes the value an array without a look-up
+                        if ((token_size == 1 && data[pos + 1] == '0') || arrays.contains(data, pos))
                         {
                             // some reference token below this position is 0, so the
                             // value is an array
+                            *current = BasicJsonType(detail::value_t::array);
+                            reserve_elements(*current->m_data.m_value.array, 2, detail::priority_tag<1> {});
                             current = &current->operator[](array_index<BasicJsonType>(token));
                         }
                         else
@@ -39188,6 +39387,72 @@ public:
     /// @name JSON Patch functions
     /// @{
 
+  private:
+    /// the members of an operation of a JSON patch that are of interest
+    struct patch_members
+    {
+        basic_json* op = nullptr;
+        basic_json* path = nullptr;
+        basic_json* value = nullptr;
+        basic_json* from = nullptr;
+    };
+
+    /// @brief find the members "op", "path", "value", and "from" of the object @a val in one pass
+    static patch_members find_patch_members(const basic_json& val, std::true_type /*key_type is string_t*/)
+    {
+        patch_members members;
+        for (auto& member : *val.m_data.m_value.object)
+        {
+            const string_t& key = member.first;
+            switch (key.size())
+            {
+                case 2:
+                    if (key == "op")
+                    {
+                        members.op = &member.second;
+                    }
+                    break;
+                case 4:
+                    if (key == "path")
+                    {
+                        members.path = &member.second;
+                    }
+                    else if (key == "from")
+                    {
+                        members.from = &member.second;
+                    }
+                    break;
+                case 5:
+                    if (key == "value")
+                    {
+                        members.value = &member.second;
+                    }
+                    break;
+                default:
+                    break;
+            }
+        }
+        return members;
+    }
+
+    /// @brief find the members by lookup for key types other than string_t
+    static patch_members find_patch_members(const basic_json& val, std::false_type /*key_type is not string_t*/)
+    {
+        const auto find_member = [&val](const char* name) -> basic_json *
+        {
+            const auto it = val.m_data.m_value.object->find(string_t(name));
+            return it != val.m_data.m_value.object->end() ? &it->second : nullptr;
+        };
+
+        patch_members members;
+        members.op = find_member("op");
+        members.path = find_member("path");
+        members.value = find_member("value");
+        members.from = find_member("from");
+        return members;
+    }
+
+  public:
     /// @brief applies a JSON patch in-place without copying the object
     /// @sa https://json.nlohmann.me/api/basic_json/patch/
     void patch_inplace(const basic_json& json_patch)
@@ -39361,18 +39626,18 @@ public:
         // a diff creates them: apply the operation and return true; return
         // false, with nothing changed, for all others
         string_t token;
-        const string_t value_key = "value";
-        const auto try_plain = [&result, &token, &value_key](patch_operations operation, const string_t& path, const basic_json & val)
+        typename json_pointer::template plain_steps<basic_json> steps;
+        const auto try_plain = [&result, &token, &steps](patch_operations operation, const string_t& path, const patch_members & members, const basic_json & val)
         {
-            if (path.empty() || path.find_first_of('~') != string_t::npos)
+            if (path.empty())
             {
                 return false;
             }
 
             // a missing "value" is reported below
-            const auto value_it = val.m_data.m_value.object->find(value_key);
-            const basic_json& value = value_it != val.m_data.m_value.object->end() ? value_it->second : val;
-            if (operation != patch_operations::remove && value_it == val.m_data.m_value.object->end())
+            const basic_json* const value_ptr = members.value;
+            const basic_json& value = value_ptr != nullptr ? *value_ptr : val;
+            if (operation != patch_operations::remove && value_ptr == nullptr)
             {
                 return false;
             }
@@ -39381,7 +39646,7 @@ public:
             {
                 case patch_operations::replace:
                 {
-                    basic_json* const target = json_pointer::resolve_plain(&result, path, path.size(), token);
+                    basic_json* const target = json_pointer::resolve_plain(&result, path, path.size(), token, steps);
                     if (target == nullptr)
                     {
                         return false;
@@ -39392,7 +39657,7 @@ public:
 
                 case patch_operations::test:
                 {
-                    const basic_json* const target = json_pointer::resolve_plain(&result, path, path.size(), token);
+                    const basic_json* const target = json_pointer::resolve_plain(&result, path, path.size(), token, steps);
                     // a failing test is reported below
                     return target != nullptr && *target == value;
                 }
@@ -39412,13 +39677,17 @@ public:
                     }
                     --slash;
 
-                    basic_json* const parent = json_pointer::resolve_plain(&result, path, slash, token);
+                    basic_json* const parent = json_pointer::resolve_plain(&result, path, slash, token, steps);
                     if (parent == nullptr)
                     {
                         return false;
                     }
                     token.clear();
                     token.append(path.data() + slash + 1, path.size() - slash - 1);
+                    if (token.find_first_of('~') != string_t::npos)
+                    {
+                        return false;
+                    }
 
                     if (operation == patch_operations::add)
                     {
@@ -39474,31 +39743,32 @@ public:
             }
         };
 
+        // the name of the first member to check
+        const string_t op_member = "op";
+
         // iterate and apply the operations
         for (const auto& val : json_patch)
         {
             // wrapper to get a value for an operation
-            const auto get_value = [&val](const string_t& op,
-                                          const string_t& member,
+            const auto get_value = [&val](basic_json * found,
+                                          const string_t& op,
+                                          const char* member,
                                           bool string_type) -> basic_json &
             {
-                // find value
-                auto it = val.m_data.m_value.object->find(member);
-
                 // check if the desired value is present
-                if (JSON_HEDLEY_UNLIKELY(it == val.m_data.m_value.object->end()))
+                if (JSON_HEDLEY_UNLIKELY(found == nullptr))
                 {
-                    detail::throw_patch_missing_member(op, member, false, val);
+                    detail::throw_patch_missing_member(op, string_t(member), false, val);
                 }
 
                 // check if the result is of type string
-                if (JSON_HEDLEY_UNLIKELY(string_type && !it->second.is_string()))
+                if (JSON_HEDLEY_UNLIKELY(string_type && !found->is_string()))
                 {
-                    detail::throw_patch_missing_member(op, member, true, val);
+                    detail::throw_patch_missing_member(op, string_t(member), true, val);
                 }
 
                 // no error: return value
-                return it->second;
+                return *found;
             };
 
             // type check: every element of the array must be an object
@@ -39507,26 +39777,30 @@ public:
                 detail::throw_patch_not_an_array(val);
             }
 
+            const patch_members members = find_patch_members(val, std::is_same<typename object_t::key_type, string_t> {});
+
             // collect mandatory members
-            const string_t& op = *get_value("op", "op", true).m_data.m_value.string;
-            const string_t& path = *get_value(op, "path", true).m_data.m_value.string;
+            const string_t& op = *get_value(members.op, op_member, "op", true).m_data.m_value.string;
+            const string_t& path = *get_value(members.path, op, "path", true).m_data.m_value.string;
             const patch_operations operation = get_op(op);
 
             // the usual operations on a plain pointer are applied without
             // building the pointer's reference tokens; anything else (and
             // every error) is handled below
-            if (try_plain(operation, path, val))
+            if (try_plain(operation, path, members, val))
             {
                 continue;
             }
 
+            // the general operations may change any container
+            steps.reset();
             json_pointer ptr(path);
 
             switch (operation)
             {
                 case patch_operations::add:
                 {
-                    operation_add(ptr, get_value("add", "value", false));
+                    operation_add(ptr, get_value(members.value, "add", "value", false));
                     break;
                 }
 
@@ -39539,13 +39813,13 @@ public:
                 case patch_operations::replace:
                 {
                     // the "path" location must exist - use at()
-                    result.at(ptr) = get_value("replace", "value", false);
+                    result.at(ptr) = get_value(members.value, "replace", "value", false);
                     break;
                 }
 
                 case patch_operations::move:
                 {
-                    const string_t& from_path = *get_value("move", "from", true).m_data.m_value.string;
+                    const string_t& from_path = *get_value(members.from, "move", "from", true).m_data.m_value.string;
                     json_pointer from_ptr(from_path);
 
                     if (JSON_HEDLEY_UNLIKELY(is_proper_prefix(from_ptr, ptr)))
@@ -39568,7 +39842,7 @@ public:
 
                 case patch_operations::copy:
                 {
-                    const string_t& from_path = *get_value("copy", "from", true).m_data.m_value.string;
+                    const string_t& from_path = *get_value(members.from, "copy", "from", true).m_data.m_value.string;
                     const json_pointer from_ptr(from_path);
 
                     // The copy is functionally identical to an "add"
@@ -39586,7 +39860,7 @@ public:
                     {
                         // check if "value" matches the one at "path"
                         // the "path" location must exist - use at()
-                        success = (result.at(ptr) == get_value("test", "value", false));
+                        success = (result.at(ptr) == get_value(members.value, "test", "value", false));
                     }
                     JSON_INTERNAL_CATCH (out_of_range&)
                     {
@@ -39678,13 +39952,18 @@ public:
     /// @brief append an operation @a op for @a path to @a result, with @a value if it is not null
     static void diff_operation(basic_json& result, const char* op, const string_t& path, const basic_json* value)
     {
+        // the keys are distinct and in the order of std::map; the members are
+        // added without looking them up
         basic_json entry(value_t::object);
-        entry["op"] = op;
-        entry["path"] = path;
+        auto& members = *entry.m_data.m_value.object;
+        typename object_t::iterator hint = members.end();
+        json_pointer::add_flattened(members, hint, string_t("op"), string_t(op), detail::priority_tag<2> {});
+        json_pointer::add_flattened(members, hint, string_t("path"), path, detail::priority_tag<2> {});
         if (value != nullptr)
         {
-            entry["value"] = *value;
+            json_pointer::add_flattened(members, hint, string_t("value"), *value, detail::priority_tag<2> {});
         }
+        entry.set_parents();
         result.push_back(std::move(entry));
     }
 
@@ -39706,6 +39985,50 @@ public:
         diff_operation(result, "add", path, &value);
     }
 
+    /// @brief the values in the target of the members of a source object, for the
+    ///        objects of up to 16 members without allocating
+    ///
+    /// reserve() must be called with the number of values that are added.
+    class diff_target_values
+    {
+      public:
+        diff_target_values() = default;
+        diff_target_values(const diff_target_values&) = delete;
+        diff_target_values& operator=(const diff_target_values&) = delete;
+        ~diff_target_values() = default;
+
+        void reserve(const std::size_t n)
+        {
+            if (n > inline_size)
+            {
+                large.resize(n);
+                items = large.data();
+            }
+        }
+
+        void push_back(const basic_json* value)
+        {
+            items[count++] = value;
+        }
+
+        std::size_t size() const noexcept
+        {
+            return count;
+        }
+
+        const basic_json* operator[](const std::size_t i) const noexcept
+        {
+            return items[i];
+        }
+
+      private:
+        static constexpr std::size_t inline_size = 16;
+        std::size_t count = 0;
+        const basic_json** items = inline_items;
+        std::vector<const basic_json*> large{}; // NOLINT(readability-redundant-member-init)
+        const basic_json* inline_items[inline_size]; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init)
+    };
+
     /// @brief append "/" and the decimal representation of @a index to @a path
     static void diff_append_index(string_t& path, std::size_t index)
     {
@@ -39786,8 +40109,9 @@ public:
     operations that remove every member of @a source and add every member of
     @a target to @a result, and returns false.
     */
+    template<typename TargetValues>
     static bool diff_object_keys(basic_json& result, const basic_json& source, const basic_json& target,
-                                 const string_t& path, std::vector<const basic_json*>& target_values,
+                                 const string_t& path, TargetValues& target_values,
                                  std::vector<const_iterator>& added)
     {
         // first pass: one lookup per source key
@@ -40001,7 +40325,7 @@ public:
 
             case value_t::object:
             {
-                std::vector<const basic_json*> target_values;
+                diff_target_values target_values;
                 std::vector<const_iterator> added;
                 if (diff_object_keys(result, source, target, path, target_values, added))
                 {

single_include/nlohmann/json_view.hpp

@@ -756,34 +756,6 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* vector_plain_run(const unsigned
     }
     return p;
 }
-
-/*!
-@brief copy 16 bytes from p to w, and find the first quote, backslash,
-control character, or non-ASCII byte among them
-
-The bytes are copied whether or not they are all plain (the caller has room
-for 16 bytes and keeps only the plain ones).
-
-@return the offset of that byte, or 16 if there is none
-*/
-NLOHMANN_VIEW_ALWAYS_INLINE unsigned copy_plain_run16(const unsigned char* p, char* w) noexcept
-{
-#if NLOHMANN_VIEW_NEON
-    const uint8x16_t in = vld1q_u8(p);
-    vst1q_u8(reinterpret_cast<std::uint8_t*>(w), in); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
-    const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))),
-                                        vcltq_s8(vreinterpretq_s8_u8(in), vdupq_n_s8(0x20)));
-    const std::uint64_t bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
-    return bits != 0 ? static_cast<unsigned>(count_trailing_zeros(bits) >> 2u) : 16u;
-#else
-    const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p))); // NOLINT(bugprone-casting-through-void)
-    _mm_storeu_si128(static_cast<__m128i*>(static_cast<void*>(w)), in); // NOLINT(bugprone-casting-through-void)
-    const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
-                                         _mm_cmplt_epi8(in, _mm_set1_epi8(0x20)));
-    const auto bits = static_cast<std::uint64_t>(static_cast<unsigned>(_mm_movemask_epi8(special)));
-    return bits != 0 ? static_cast<unsigned>(count_trailing_zeros(bits)) : 16u;
-#endif
-}
 #endif
 
 #if NLOHMANN_VIEW_SSSE3_DISPATCH
@@ -1465,41 +1437,11 @@ class builder
                 0, 0, '\b', 0, 0, 0, '\f', 0, 0, 0, 0, 0, 0, 0, '\n', 0, 0, 0, '\r', 0, '\t', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
             }
         };
-        // The write position is kept in locals: the stores of characters into
-        // the arena may alias the members of the builder, which would then be
-        // reloaded after every one. It is stored back where the arena grows
-        // and at the end.
-        const unsigned char* const end = m_end;
         const std::size_t start = arena_used();
-        char* w = m_arena_write;
-        const char* w_end = m_arena_end;
-#define NLOHMANN_VIEW_ENSURE(n)                                                       \
-    if (NLOHMANN_VIEW_UNLIKELY(static_cast<std::size_t>(w_end - w) < (n)))            \
-    {                                                                                 \
-        m_arena_write = w;                                                            \
-        arena_grow(n);                                                                \
-        w = m_arena_write;                                                            \
-        w_end = m_arena_end;                                                          \
-    }
-        {
-            const auto n = static_cast<std::size_t>(p - s);
-            if (n <= 16 && end - s >= 16)
-            {
-                NLOHMANN_VIEW_ENSURE(16)
-                std::memcpy(w, s, 16);
-            }
-            else if (n != 0)
-            {
-                // (an empty run leaves an empty arena unallocated, and memcpy()
-                // must not be passed its null pointer even for zero bytes)
-                NLOHMANN_VIEW_ENSURE(n)
-                std::memcpy(w, s, n);
-            }
-            w += n;
-        }
+        arena_run(s, static_cast<std::size_t>(p - s));
         for (;;)
         {
-            if (p == end)
+            if (p == m_end)
             {
                 return failed(error_code::string_missing_quote, p);
             }
@@ -1507,7 +1449,6 @@ class builder
             if (c == '"')
             {
                 ++p;
-                m_arena_write = w;
                 return decoded{p, start, arena_used() - start};
             }
             if (c != '\\')
@@ -1518,7 +1459,7 @@ class builder
                 return failed(c < 0x20 ? error_code::string_control_character : error_code::string_utf8, p);
             }
             ++p;
-            if (p == end)
+            if (p == m_end)
             {
                 return failed(error_code::string_missing_quote, p);
             }
@@ -1536,7 +1477,7 @@ class builder
                     {
                         return failed(error_code::string_surrogate_low, p);
                     }
-                    if (end - p < 2 || p[0] != '\\' || p[1] != 'u')
+                    if (m_end - p < 2 || p[0] != '\\' || p[1] != 'u')
                     {
                         return failed(error_code::string_surrogate_high, p);
                     }
@@ -1552,108 +1493,27 @@ class builder
                     }
                     cp = 0x10000 + ((cp - 0xD800) << 10) + (lo - 0xDC00);
                 }
-                NLOHMANN_VIEW_ENSURE(4)
-                w = put_utf8(w, cp);
+                arena_ensure(4);
+                m_arena_write = put_utf8(m_arena_write, cp);
             }
             else if (NLOHMANN_VIEW_LIKELY(d < 128 && simple_escape[d] != 0))
             {
-                NLOHMANN_VIEW_ENSURE(1)
-                *w++ = simple_escape[d];
+                arena_ensure(1);
+                *m_arena_write++ = simple_escape[d];
             }
             else
             {
                 --p;
                 return failed(error_code::string_escape, p);
             }
-#if NLOHMANN_VIEW_NEON
-            if (p != end && *p == '\\')
+            if (p != m_end && *p == '\\')
             {
                 continue; // consecutive escapes ("\u00e4\u00f6"): no run in between
             }
-            // The first 16 bytes of the run are checked one by one, in predicted branches, and copied
-            // as one block: where the runs between escapes are short, the vector step below would put
-            // its longer dependency chain (load, compare, mask, count, add) on p for each of them,
-            // and be slower than these steps (the scanner of the keys works the same way)
-            {
-                if (end - p >= 16)
-                {
-                    const std::uint8_t* const plain = string_plain();
-                    std::size_t steps = 16;
-#define NLOHMANN_VIEW_STEP(i) if (NLOHMANN_VIEW_LIKELY(plain[p[i]] != 0)) {} else { steps = (i); goto run_found; }
-                    NLOHMANN_VIEW_REPEAT16(NLOHMANN_VIEW_STEP)
-#undef NLOHMANN_VIEW_STEP
-run_found:
-                    NLOHMANN_VIEW_ENSURE(16)
-                    std::memcpy(w, p, 16); // (only the first `steps` bytes are kept)
-                    w += steps;
-                    p += steps;
-                    if (steps < 16)
-                    {
-                        if (*p >= 0x80)
-                        {
-                            // non-ASCII: the UTF-8 check, and the rest of the run
-                            const unsigned char* const r = p;
-                            p = scan_string_run(p, end);
-                            const auto n = static_cast<std::size_t>(p - r);
-                            NLOHMANN_VIEW_ENSURE(n)
-                            std::memcpy(w, r, n);
-                            w += n;
-                        }
-                        continue;
-                    }
-                }
-            }
-#else
-            if (p != end && (*p == '\\' || *p == '"'))
-            {
-                continue; // consecutive escapes ("\u00e4\u00f6"), or the end of the string: no run in between
-            }
-#endif
-#if NLOHMANN_VIEW_VECTOR
-            // the plain bytes up to the next quote, backslash, or control
-            // character are copied as they are scanned, 16 bytes at a time
-            for (;;)
-            {
-                if (NLOHMANN_VIEW_UNLIKELY(end - p < 16))
-                {
-                    const unsigned char* const r = p;
-                    p = scan_string_run(p, end);
-                    const auto n = static_cast<std::size_t>(p - r);
-                    NLOHMANN_VIEW_ENSURE(n)
-                    std::memcpy(w, r, n);
-                    w += n;
-                    break;
-                }
-                NLOHMANN_VIEW_ENSURE(16)
-                const unsigned k = copy_plain_run16(p, w);
-                w += k;
-                p += k;
-                if (k == 16)
-                {
-                    continue;
-                }
-                if (NLOHMANN_VIEW_UNLIKELY(*p >= 0x80))
-                {
-                    // non-ASCII: the UTF-8 check, and the rest of the run
-                    const unsigned char* const r = p;
-                    p = scan_string_run(p, end);
-                    const auto n = static_cast<std::size_t>(p - r);
-                    NLOHMANN_VIEW_ENSURE(n)
-                    std::memcpy(w, r, n);
-                    w += n;
-                }
-                break;
-            }
-#else
             const unsigned char* const r = p;
-            p = scan_string_run(p, end);
-            const auto n = static_cast<std::size_t>(p - r);
-            NLOHMANN_VIEW_ENSURE(n)
-            std::memcpy(w, r, n);
-            w += n;
-#endif
+            p = scan_string_run(p, m_end);
+            arena_run(r, static_cast<std::size_t>(p - r));
         }
-#undef NLOHMANN_VIEW_ENSURE
     }
 
     /// does the float token [s, p) overflow FloatType? (parse() rejects it)
@@ -1699,6 +1559,14 @@ run_found:
         return m_arena_write != nullptr ? static_cast<std::size_t>(m_arena_write - m_doc.arena.data()) : 0;
     }
 
+    NLOHMANN_VIEW_ALWAYS_INLINE void arena_ensure(std::size_t n)
+    {
+        if (NLOHMANN_VIEW_UNLIKELY(static_cast<std::size_t>(m_arena_end - m_arena_write) < n))
+        {
+            arena_grow(n);
+        }
+    }
+
     NLOHMANN_VIEW_NOINLINE void arena_grow(std::size_t n)
     {
         const std::size_t used = arena_used();
@@ -1707,6 +1575,25 @@ run_found:
         m_arena_end = m_doc.arena.data() + m_doc.arena.size();
     }
 
+    /// append the run [r, r + n) to the arena; short runs as one fixed-size
+    /// 16-byte move when both sides have the room (no library call)
+    NLOHMANN_VIEW_ALWAYS_INLINE void arena_run(const unsigned char* r, std::size_t n)
+    {
+        if (n <= 16 && m_end - r >= 16)
+        {
+            arena_ensure(16);
+            std::memcpy(m_arena_write, r, 16);
+        }
+        else if (n != 0)
+        {
+            // (an empty run leaves an empty arena unallocated, and memcpy()
+            // must not be passed its null pointer even for zero bytes)
+            arena_ensure(n);
+            std::memcpy(m_arena_write, r, n);
+        }
+        m_arena_write += n;
+    }
+
     /// UTF-8 encoding of cp at w (room for 4 bytes); returns the position after
     /// it. (A returned pointer stays in a register; writing through a
     /// reference to m_arena_write would store and reload it around every byte.)
@@ -2229,11 +2116,11 @@ indent_done:
                 ++p;
             }
             const unsigned char* const int_start = p;
-            if (cur() == '0')
+            if (p != e && *p == '0')
             {
                 ++p;
             }
-            else if (NLOHMANN_VIEW_LIKELY(cur() >= '1' && cur() <= '9'))
+            else if (NLOHMANN_VIEW_LIKELY(p != e && *p >= '1' && *p <= '9'))
             {
                 p = skip_digits(p + 1, e);
             }
@@ -2244,7 +2131,7 @@ indent_done:
             const auto int_digits = static_cast<std::size_t>(p - int_start);
             std::size_t frac_digits = 0;
             bool is_float = false;
-            if (cur() == '.')
+            if (p != e && *p == '.')
             {
                 ++p;
                 const unsigned char* const f0 = p;
@@ -2257,20 +2144,20 @@ indent_done:
                 is_float = true;
             }
             std::int64_t exponent = 0;
-            if ((cur() | 0x20) == 'e')
+            if (p != e && (*p | 0x20) == 'e')
             {
                 ++p;
                 bool exp_negative = false;
-                if (cur() == '+' || cur() == '-')
+                if (p != e && (*p == '+' || *p == '-'))
                 {
                     exp_negative = *p == '-';
                     ++p;
                 }
-                if (NLOHMANN_VIEW_UNLIKELY(!is_digit(cur())))
+                if (NLOHMANN_VIEW_UNLIKELY(p == e || !is_digit(*p)))
                 {
                     return fail(error_code::number_after_exponent);
                 }
-                while (is_digit(cur()))
+                while (p != e && is_digit(*p))
                 {
                     if (exponent < 100000)
                     {
@@ -2332,7 +2219,7 @@ indent_done:
             ++p; // opening quote
             const unsigned char* const s = p;
             p = scan_string_run<Value>(p, e);
-            if (NLOHMANN_VIEW_LIKELY(cur() == '"'))
+            if (NLOHMANN_VIEW_LIKELY(p != e && *p == '"'))
             {
                 push_node(value_t::string, 0, 0, static_cast<std::size_t>(s - b), static_cast<std::uint64_t>(p - s));
                 ++p;
@@ -3281,96 +3168,27 @@ constexpr std::size_t index_max_displacement = 64;
 static_assert(document_data::index_min_members >= 2 * index_max_displacement,
               "a table must be much larger than the probe window of a lookup");
 
-/// hash of a key: its bytes, eight at a time (in a fixed byte order), where the
-/// last word may overlap the one before (so that no loop over single bytes is
-/// needed); a key of fewer than eight bytes is read as two overlapping words of
-/// four or two bytes (in the native byte order: the hash is not stored, and the
-/// same on both sides of a lookup)
+/// hash of a key: its bytes, eight at a time, in a fixed byte order
 inline std::uint64_t key_hash(const char* s, std::size_t n) noexcept
 {
     std::uint64_t h = 0x9E3779B97F4A7C15u * (n + 1);
     const auto* p = reinterpret_cast<const unsigned char*>(s); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    while (n >= 8)
+    {
+        h = (h ^ read_eight_bytes(p)) * 0xBF58476D1CE4E5B9u;
+        h ^= h >> 29u;
+        p += 8;
+        n -= 8;
+    }
     std::uint64_t w = 0;
-    if (n >= 8)
+    for (std::size_t i = 0; i < n; ++i)
     {
-        const unsigned char* const last = p + n - 8;
-        while (p < last)
-        {
-            h = (h ^ read_eight_bytes(p)) * 0xBF58476D1CE4E5B9u;
-            h ^= h >> 29u;
-            p += 8;
-        }
-        w = read_eight_bytes(last);
+        w |= static_cast<std::uint64_t>(p[i]) << (8u * i);
     }
-    else if (n >= 4)
-    {
-        std::uint32_t head = 0;
-        std::uint32_t tail = 0;
-        std::memcpy(&head, p, 4);
-        std::memcpy(&tail, p + n - 4, 4);
-        w = static_cast<std::uint64_t>(head) | (static_cast<std::uint64_t>(tail) << 32u);
-    }
-    else if (n >= 2)
-    {
-        std::uint16_t head = 0;
-        std::uint16_t tail = 0;
-        std::memcpy(&head, p, 2);
-        std::memcpy(&tail, p + n - 2, 2);
-        w = static_cast<std::uint64_t>(head) | (static_cast<std::uint64_t>(tail) << 16u);
-    }
-    else if (n == 1)
-    {
-        w = p[0];
-    }
-    // (a product only carries bits upwards, and the slot is taken from the low
-    // bits: the high bits of the last word are folded down before the multiplication)
-    h = (h ^ w ^ (w >> 29u)) * 0x94D049BB133111EBu;
+    h = (h ^ w) * 0x94D049BB133111EBu;
     return h ^ (h >> 31u);
 }
 
-/// whether the n <= 16 bytes at a and b are equal, as two overlapping words
-/// (the first and the last 8, 4, or 2 bytes) and without a call
-NLOHMANN_VIEW_ALWAYS_INLINE bool same_short_bytes(const unsigned char* a, const unsigned char* b, std::size_t n) noexcept
-{
-    if (n >= 8)
-    {
-        std::uint64_t x0 = 0;
-        std::uint64_t x1 = 0;
-        std::uint64_t y0 = 0;
-        std::uint64_t y1 = 0;
-        std::memcpy(&x0, a, 8);
-        std::memcpy(&x1, a + n - 8, 8);
-        std::memcpy(&y0, b, 8);
-        std::memcpy(&y1, b + n - 8, 8);
-        return x0 == y0 && x1 == y1;
-    }
-    if (n >= 4)
-    {
-        std::uint32_t x0 = 0;
-        std::uint32_t x1 = 0;
-        std::uint32_t y0 = 0;
-        std::uint32_t y1 = 0;
-        std::memcpy(&x0, a, 4);
-        std::memcpy(&x1, a + n - 4, 4);
-        std::memcpy(&y0, b, 4);
-        std::memcpy(&y1, b + n - 4, 4);
-        return x0 == y0 && x1 == y1;
-    }
-    if (n >= 2)
-    {
-        std::uint16_t x0 = 0;
-        std::uint16_t x1 = 0;
-        std::uint16_t y0 = 0;
-        std::uint16_t y1 = 0;
-        std::memcpy(&x0, a, 2);
-        std::memcpy(&x1, a + n - 2, 2);
-        std::memcpy(&y0, b, 2);
-        std::memcpy(&y1, b + n - 2, 2);
-        return x0 == y0 && x1 == y1;
-    }
-    return n == 0 || *a == *b;
-}
-
 /// build the table of a large object
 inline void build_object_index(document_data& d, node* obj)
 {
@@ -3435,27 +3253,6 @@ inline const node* find_indexed(const document_data& d, const node* obj, const c
     const document_data::object_index& ix = d.indexes[obj->extra - 1u];
     const std::uint32_t* const table = d.index_slots.data() + ix.start;
     std::size_t slot = conditional_static_cast<std::size_t>(key_hash(key, n)) & ix.mask;
-    const auto* const k_bytes = reinterpret_cast<const unsigned char*>(key); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
-    // (the loop for longer keys comes first, as the code is laid out; it is not the more common case)
-    if (NLOHMANN_VIEW_UNLIKELY(n <= 16))
-    {
-        // (up to 16 bytes, the bytes are compared as two words, without a call)
-        for (std::size_t distance = 0; distance <= index_max_displacement; ++distance)
-        {
-            const std::uint32_t s = table[slot];
-            if (s == 0)
-            {
-                return nullptr;
-            }
-            const node* const k = obj + s;
-            if (k->len == n && same_short_bytes(reinterpret_cast<const unsigned char*>(d.str(*k)), k_bytes, n)) // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
-            {
-                return k;
-            }
-            slot = (slot + 1) & ix.mask;
-        }
-        return nullptr;
-    }
     for (std::size_t distance = 0; distance <= index_max_displacement; ++distance)
     {
         const std::uint32_t s = table[slot];
@@ -3624,10 +3421,6 @@ const node* element_at(const document_data& d, const node* array, std::size_t id
     {
         return e + idx; // a growable block: one link per element
     }
-    if (array->next == array->len + 1u && (!nav::editable() || (array->flags & node_flags::moved) == 0))
-    {
-        return e + idx; // no element has a subtree: the elements are the nodes after the array
-    }
     for (std::size_t i = 0; i < idx; ++i)
     {
         e = document_data::after(e);
@@ -3643,10 +3436,6 @@ const node* last_child(const document_data& d, const node* container) noexcept
     const std::size_t value_offset = container->kind == static_cast<std::uint8_t>(value_t::object) ? 1 : 0;
     const node* const end = navigation<Editable>::end(d, container);
     const node* last = navigation<Editable>::first(d, container);
-    if (value_offset == 0 && container->next == container->len + 1u && (!navigation<Editable>::editable() || (container->flags & node_flags::moved) == 0))
-    {
-        return last + (container->len - 1u); // an array without subtrees: the elements are the nodes after it
-    }
     for (const node* c = document_data::after(last + value_offset); c != end; c = document_data::after(c + value_offset))
     {
         last = c;
@@ -5512,9 +5301,6 @@ NLOHMANN_JSON_NAMESPACE_END
 
 #include <algorithm> // max
 #include <cstddef> // size_t
-#ifndef JSON_NO_IO
-    #include <cstdio> // FILE, fread
-#endif
 #include <istream> // istream, streambuf
 #include <string> // basic_string, char_traits, string
 #include <type_traits> // decay, integral_constant, is_array, is_const, is_integral, is_lvalue_reference, is_pointer, is_same, remove_cv, remove_extent, remove_pointer, remove_reference
@@ -5660,37 +5446,6 @@ inline void append_stream(std::string& buf, std::istream& is)
     is.clear(is.rdstate() | std::ios::eofbit);
 }
 
-/// a pointer to a C stream (never with JSON_NO_IO, which leaves out <cstdio>)
-template<typename T>
-struct is_c_stream
-#ifndef JSON_NO_IO
-    : std::is_same<T, std::FILE*>
-#else
-    : std::false_type
-#endif
-{};
-
-#ifndef JSON_NO_IO
-/// append the rest of a C stream: in blocks with fread, not character by
-/// character (the library's file adapter reads with fgetc);
-/// f is not null
-inline void append_file(std::string& buf, std::FILE* f)
-{
-    for (;;)
-    {
-        const std::size_t used = buf.size();
-        const std::size_t room = (std::max)(buf.capacity() - used, std::size_t{4096});
-        buf.resize(used + room);
-        const std::size_t got = std::fread(&buf[used], 1, room, f);
-        buf.resize(used + got);
-        if (got < room)
-        {
-            break; // end of file, or an error (as fgetc, which returns EOF for both)
-        }
-    }
-}
-#endif
-
 }  // namespace view
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END
@@ -5849,21 +5604,20 @@ class view_item
 
     view_item(const iterator& it, std::size_t index)
         : m_it(it)
-        , m_position(index)
-    {}
+    {
+        if (!it.is_object_iterator())
+        {
+            m_index = std::to_string(index);
+        }
+    }
 
-    /// the member key, or the element index for arrays (as text made on the
-    /// first call, so that iterating over the values pays nothing for it)
+    /// the member key, or the element index for arrays
     string_view_t key() const
     {
         if (m_it.is_object_iterator())
         {
             return m_it.key();
         }
-        if (m_index.empty())
-        {
-            m_index = std::to_string(m_position);
-        }
         return string_view_t(m_index.data(), m_index.size());
     }
 
@@ -5886,8 +5640,7 @@ class view_item
 
   private:
     iterator m_it;
-    std::size_t m_position; ///< the index of an array element
-    mutable std::string m_index{}; ///< the text of m_position, once key() was called // NOLINT(readability-redundant-member-init)
+    std::string m_index{}; // NOLINT(readability-redundant-member-init)
 };
 
 /// the range returned by basic_json_view::items()
@@ -5981,7 +5734,7 @@ NLOHMANN_JSON_NAMESPACE_END
 
 
 
-#include <array> // array
+#include <algorithm> // max
 #include <cstddef> // size_t
 #include <cstdint> // int64_t, uint8_t
 #include <string> // string
@@ -6021,9 +5774,8 @@ BasicJsonType materialize(const document_data& d, const node* n)
     using nav = navigation<Editable>;
 
     // the open containers: their next element (or key of the next member),
-    // their end, and whether they are objects; for the first 16 levels on the
-    // stack, else sized once from the document's deepest nesting (for a
-    // subtree an upper bound)
+    // their end, and whether they are objects; sized once from the
+    // document's deepest nesting (for a subtree an upper bound)
     struct frame
     {
         const node* pos;
@@ -6031,43 +5783,10 @@ BasicJsonType materialize(const document_data& d, const node* n)
         bool object;
     };
 
-    // a scalar needs neither the handler nor the stack of open containers
-    switch (static_cast<value_t>(n->kind))
-    {
-        case value_t::string:
-            return BasicJsonType(string_t(d.str(*n), n->len));
-        case value_t::number_integer:
-            return BasicJsonType(static_cast<typename BasicJsonType::number_integer_t>(static_cast<std::int64_t>(integer_bits(*n))));
-        case value_t::number_unsigned:
-            return BasicJsonType(static_cast<typename BasicJsonType::number_unsigned_t>(integer_bits(*n)));
-        case value_t::number_float:
-            return BasicJsonType(float_value<typename BasicJsonType::number_float_t>(d, *n));
-        case value_t::boolean:
-            return BasicJsonType((n->flags & node_flags::is_true) != 0);
-        case value_t::null:
-            return BasicJsonType(nullptr);
-        case value_t::object:
-        case value_t::array:
-        case value_t::binary:
-        case value_t::discarded:
-        default:
-            break;
-    }
-
     BasicJsonType result;
     sax_t sax(result, true);
     const string_t no_token{};
-    // (shallow subtrees on the stack: a call for a small value then allocates only for the value)
-    std::array<frame, 16> shallow; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): filled as containers open
-    std::vector<frame> deep{};
-    frame* open = shallow.data();
-    std::size_t capacity = shallow.size();
-    if (d.max_depth > capacity)
-    {
-        deep.resize(d.max_depth);
-        open = deep.data();
-        capacity = deep.size();
-    }
+    std::vector<frame> open((std::max)(d.max_depth, std::size_t{1}));
     std::size_t depth = 0;
     for (;;)
     {
@@ -6087,13 +5806,9 @@ BasicJsonType materialize(const document_data& d, const node* n)
                 {
                     sax.start_array(n->len);
                 }
-                if (NLOHMANN_VIEW_UNLIKELY(depth == capacity))
+                if (NLOHMANN_VIEW_UNLIKELY(depth == open.size()))
                 {
-                    // (deeper than the recorded nesting, e.g. after edits)
-                    deep.assign(open, open + depth);
-                    deep.resize(depth * 2);
-                    open = deep.data();
-                    capacity = deep.size();
+                    open.resize(depth * 2); // (deeper than the recorded nesting, e.g. after edits)
                 }
                 open[depth++] = frame{nav::first(d, n), nav::end(d, n), object};
                 break;
@@ -7875,7 +7590,7 @@ class basic_json_view
             }
             detail::view::throw_type_error(305, "cannot use operator[] with a numeric argument with ", type_name());
         }
-        return idx < m_node->len ? element(idx) : basic_json_view();
+        return idx < m_node->len ? basic_json_view(m_doc, navigation::value(detail::view::element_at<Editable>(*m_doc, m_node, idx))) : basic_json_view();
     }
 
     /// any other integer type (int, unsigned, long, std::int64_t, ...; a
@@ -7938,7 +7653,7 @@ class basic_json_view
         {
             detail::view::throw_out_of_range(401, detail::concat("array index ", std::to_string(idx), " is out of range"));
         }
-        return element(idx);
+        return basic_json_view(m_doc, navigation::value(detail::view::element_at<Editable>(*m_doc, m_node, idx)));
     }
 
     /// any other integer type, see operator[]; negative values are out of
@@ -7972,13 +7687,7 @@ class basic_json_view
 
     string_t value(string_view_t key, const char* default_value) const
     {
-        if (NLOHMANN_VIEW_UNLIKELY(!is_object()))
-        {
-            detail::view::throw_type_error(306, "cannot use value() with ", type_name());
-        }
-        // (the default is made only if there is no such member)
-        const basic_json_view r = lookup(key);
-        return r.is_discarded() ? string_t(default_value) : r.template get<string_t>();
+        return value(key, string_t(default_value));
     }
 
     /// the value a JSON pointer refers to converted to T, or the default
@@ -7997,12 +7706,7 @@ class basic_json_view
 
     string_t value(const json_pointer& ptr, const char* default_value) const
     {
-        if (NLOHMANN_VIEW_UNLIKELY(!is_structured()))
-        {
-            detail::view::throw_type_error(306, "cannot use value() with ", type_name());
-        }
-        const basic_json_view r = detail::view::resolve_pointer(*this, detail::json_pointer_access::reference_tokens(ptr), detail::view::pointer_mode::value);
-        return r.is_discarded() ? string_t(default_value) : r.template get<string_t>();
+        return value(ptr, string_t(default_value));
     }
 
     /// the first element or member value; a primitive value itself. Throws
@@ -8024,8 +7728,7 @@ class basic_json_view
     {
         if (is_structured() && m_node->len != 0)
         {
-            return unedited() ? basic_json_view(m_doc, detail::view::last_child<false>(*m_doc, m_node) + (is_object() ? 1 : 0))
-                   : basic_json_view(m_doc, navigation::value(detail::view::last_child<Editable>(*m_doc, m_node) + (is_object() ? 1 : 0)));
+            return basic_json_view(m_doc, navigation::value(detail::view::last_child<Editable>(*m_doc, m_node) + (is_object() ? 1 : 0)));
         }
         return front();
     }
@@ -8042,8 +7745,7 @@ class basic_json_view
         {
             return end();
         }
-        const node* const k = unedited() ? detail::view::find_member<false>(*m_doc, m_node, key.data(), key.size())
-                              : detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size());
+        const node* const k = detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size());
         return k != nullptr ? iterator(m_doc, k, true) : end();
     }
 
@@ -8060,8 +7762,7 @@ class basic_json_view
     /// whether this is an object with a member with this key
     bool contains(string_view_t key) const
     {
-        return is_object() && (unedited() ? detail::view::find_member<false>(*m_doc, m_node, key.data(), key.size()) != nullptr
-                               : detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size()) != nullptr);
+        return is_object() && detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size()) != nullptr;
     }
 
     bool contains(const char* key) const
@@ -8221,14 +7922,7 @@ class basic_json_view
         // the compact writer keeps 64 bytes of slack, so that it does not grow
         // the buffer just before the end
         const std::size_t estimate = source_extent() + (style.pretty ? source_extent() / 2 : 0) + 160;
-        if (unedited())
-        {
-            detail::view::view_serializer<BasicJsonType, false>(*m_doc, out, estimate, style).dump(m_node);
-        }
-        else
-        {
-            detail::view::view_serializer<BasicJsonType, Editable>(*m_doc, out, estimate, style).dump(m_node);
-        }
+        detail::view::view_serializer<BasicJsonType, Editable>(*m_doc, out, estimate, style).dump(m_node);
         return out;
     }
 
@@ -8308,7 +8002,7 @@ class basic_json_view
         {
             return BasicJsonType(value_t::discarded);
         }
-        return unedited() ? detail::view::materialize<BasicJsonType, false>(*m_doc, m_node) : detail::view::materialize<BasicJsonType, Editable>(*m_doc, m_node);
+        return detail::view::materialize<BasicJsonType, Editable>(*m_doc, m_node);
     }
 
     /// byte offset of this value in the source text (for strings: of the
@@ -8386,32 +8080,10 @@ class basic_json_view
     /// (object required)
     NLOHMANN_VIEW_ALWAYS_INLINE basic_json_view lookup(string_view_t key) const noexcept
     {
-        if (unedited())
-        {
-            const node* const k = detail::view::find_member<false>(*m_doc, m_node, key.data(), key.size());
-            return k != nullptr ? basic_json_view(m_doc, k + 1) : basic_json_view();
-        }
         const node* const k = detail::view::find_member<Editable>(*m_doc, m_node, key.data(), key.size());
         return k != nullptr ? basic_json_view(m_doc, navigation::value(k + 1)) : basic_json_view();
     }
 
-    /// whether the document has not been edited yet: until the first edit, its index is walked like that of a
-    /// read-only document (nothing is moved or linked), which is cheaper
-    NLOHMANN_VIEW_ALWAYS_INLINE bool unedited() const noexcept
-    {
-        return !navigation::editable() || m_doc->edits == nullptr;
-    }
-
-    /// the element of an array at an index below its size
-    NLOHMANN_VIEW_ALWAYS_INLINE basic_json_view element(size_type idx) const
-    {
-        if (unedited())
-        {
-            return basic_json_view(m_doc, detail::view::element_at<false>(*m_doc, m_node, idx));
-        }
-        return basic_json_view(m_doc, navigation::value(detail::view::element_at<Editable>(*m_doc, m_node, idx)));
-    }
-
     // --- get() dispatch ---
 
     bool get_impl(detail::view::value_tag<bool> /*unused*/, detail::priority_tag<2> /*unused*/) const
@@ -9151,8 +8823,7 @@ class basic_json_document
         // NOLINTBEGIN(readability-avoid-nested-conditional-operator): a constant expression of C++11
         append_input_impl(buf, std::forward<T>(input), std::integral_constant < int, detail::is_contiguous_byte_container<D>::value ? 0
                           : std::is_base_of<std::istream, D>::value ? 1
-                          : detail::view::is_adapter_input<D>::value ? 2
-                          : detail::view::is_c_stream<D>::value ? 4 : 3 > {});
+                          : detail::view::is_adapter_input<D>::value ? 2 : 3 > {});
         // NOLINTEND(readability-avoid-nested-conditional-operator)
     }
 
@@ -9174,19 +8845,6 @@ class basic_json_document
         detail::view::append_adapter(buf, std::move(input.ia));
     }
 
-#ifndef JSON_NO_IO
-    static void append_input_impl(std::string& buf, std::FILE* file, std::integral_constant<int, 4> /*C stream*/)
-    {
-        if (file == nullptr)
-        {
-            // (as before: the library's adapter decides what a null stream yields)
-            detail::view::append_adapter(buf, detail::input_adapter(file));
-            return;
-        }
-        detail::view::append_file(buf, file);
-    }
-#endif
-
     template<typename T>
     static void append_input_impl(std::string& buf, T&& input, std::integral_constant<int, 3> /*other*/)
     {

tests/src/unit-json_view.cpp

@@ -185,29 +185,6 @@ TEST_CASE("json_view")
         // duplicate keys: the last value, at the position of the first key
         CHECK(materialized<json_document>(R"({"a":1,"b":2,"a":3})") == json::parse(R"({"a":1,"b":2,"a":3})"));
         CHECK(materialized<ordered_json_document>(R"({"a":1,"b":2,"a":3})").dump() == R"({"a":3,"b":2})");
-        // scalars (made without the handler), and nesting around the depth up to which the stack of open containers is local
-        for (const char* scalar :
-                {"null", "true", "false", "0", "-7", "18446744073709551615", "1.5e300", "-0.0", "\"\"", "\"short\"", "\"a string that is longer than fifteen bytes\"", "\"\\u00e4\\n\""
-                })
-        {
-            CAPTURE(scalar)
-            CHECK(materialized<json_document>(scalar) == json::parse(scalar));
-            const std::string in_array = std::string("[1,") + scalar + "]";
-            const json_document d = json_document::parse(in_array);
-            CHECK(d.root()[1].materialize() == json::parse(scalar));
-            CHECK(d.root()[1].get<json>() == json::parse(scalar));
-        }
-        for (const std::size_t levels :
-                {
-                    std::size_t{1}, std::size_t{15}, std::size_t{16}, std::size_t{17}, std::size_t{32}, std::size_t{33}
-                })
-        {
-            CAPTURE(levels)
-            const std::string nested = std::string(levels, '[') + "{\"k\":[1,{\"j\":2}]}" + std::string(levels, ']');
-            CHECK(materialized<json_document>(nested) == json::parse(nested));
-            const std::string wide = "{\"a\":" + nested + ",\"b\":" + nested + "}";
-            CHECK(materialized<json_document>(wide) == json::parse(wide));
-        }
         // very deep nesting (iterative, as parse())
         const std::string deep = std::string(100000, '[') + std::string(100000, ']');
         // (one check per step, so that a failure shows which step it is)
@@ -433,31 +410,6 @@ TEST_CASE("json_view")
         std::istringstream rvalue_source("[1]");
         CHECK(json_document::parse_copy(std::move(rvalue_source)).owns_source());
 
-        // a C stream is read in blocks as well (more than one block, and a
-        // text whose length is a multiple of the block size)
-        for (const std::size_t extra :
-                {
-                    std::size_t{0}, std::size_t{1}
-                })
-        {
-            std::FILE* long_file = std::tmpfile(); // NOLINT(cppcoreguidelines-owning-memory)
-            if (long_file != nullptr)
-            {
-                std::string padded = text;
-                padded.append((4096 - (padded.size() % 4096)) % 4096 + extra, ' ');
-                CHECK(std::fwrite(padded.data(), 1, padded.size(), long_file) == padded.size());
-                CHECK(std::fseek(long_file, 0, SEEK_SET) == 0);
-                const json_document from_long_file = json_document::parse(long_file);
-                CHECK(from_long_file.source() == padded);
-                CHECK(from_long_file.root().materialize() == json::parse(text));
-                CHECK(std::fclose(long_file) == 0); // NOLINT(cppcoreguidelines-owning-memory)
-            }
-        }
-        {
-            json_document from_null;
-            CHECK_THROWS_AS(from_null = json_document::parse(static_cast<std::FILE*>(nullptr)), json::parse_error&);
-        }
-
         // a stream without a buffer is an empty input
         std::istream no_buffer(nullptr);
         CHECK(json_document::parse(no_buffer, false).is_discarded());
@@ -1054,49 +1006,6 @@ TEST_CASE("json_view element access and iteration")
 #endif
     }
 
-    SECTION("arrays whose elements have no subtrees: index and back()")
-    {
-        // (the elements are adjacent in the index; an array, an object, or an
-        // empty container anywhere makes the lookup skip element by element)
-        const std::vector<std::string> texts =
-        {
-            "[]", "[1]", "[1,2,3]", "[1,\"two\",3.5,true,null,-7,18446744073709551615]", "[[]]", "[{}]", "[1,[2],3]",
-            "[1,2,{\"a\":3}]", "[[1,2],3,4]", "[1,2,3,[4,5,6,7,8],9,10,11,12]", "[{\"a\":[1]},2]", "[\"a\\u00e4\",\"b\"]"
-        };
-        for (const std::string& text : texts)
-        {
-            CAPTURE(text)
-            const json_document d = json_document::parse(text);
-            const json_view v = d.root();
-            const json expected = json::parse(text);
-            for (std::size_t i = 0; i < expected.size(); ++i)
-            {
-                CHECK(v[i].materialize() == expected[i]);
-                CHECK(v.at(i).materialize() == expected[i]);
-            }
-            CHECK(v[expected.size()].is_discarded());
-            if (!expected.empty())
-            {
-                CHECK(v.back().materialize() == expected.back());
-            }
-        }
-        // a long array (the direct lookup is not limited to short ones), also with a container at its end
-        std::string text = "[0";
-        for (int i = 1; i < 1000; ++i)
-        {
-            text += "," + std::to_string(i);
-        }
-        const json_document scalars = json_document::parse(text + "]");
-        CHECK(scalars.root()[999].get<int>() == 999);
-        CHECK(scalars.root()[500].get<int>() == 500);
-        CHECK(scalars.root().at(1).get<int>() == 1);
-        CHECK(scalars.root().back().get<int>() == 999);
-        const json_document container_last = json_document::parse(text + ",[1000]]");
-        CHECK(container_last.root()[999].get<int>() == 999);
-        CHECK(container_last.root()[1000][0].get<int>() == 1000);
-        CHECK(container_last.root().back()[0].get<int>() == 1000);
-    }
-
     SECTION("iterators")
     {
         const json_document d = json_document::parse(R"({"x":[1,{"y":2}],"z":null})");
@@ -1136,28 +1045,6 @@ TEST_CASE("json_view element access and iteration")
         CHECK((*first++).key() == "0");
         CHECK((*first).key() == "1");
         CHECK(++first == items.end());
-
-        // the keys of array elements are their indexes, whether or not they are asked for
-        std::string numbers = "[0";
-        for (int i = 1; i < 1234; ++i)
-        {
-            numbers += "," + std::to_string(i);
-        }
-        const json_document array = json_document::parse(numbers + "]");
-        std::size_t position = 0;
-        for (const auto& item : array.root().items())
-        {
-            CHECK(item.value().get<std::size_t>() == position);
-            if (position % 3 != 0) // (not for every item: values alone do not make the key)
-            {
-                CHECK(item.key() == std::to_string(position));
-                CHECK(item.key().data() == item.key().data()); // (the same text every time)
-                const json_view::item copy = item;
-                CHECK(copy.key() == std::to_string(position));
-            }
-            ++position;
-        }
-        CHECK(position == 1234);
 #ifdef JSON_HAS_CPP_17
         std::string pairs;
         for (const auto [key, value] : d.root().items())
@@ -1496,17 +1383,7 @@ TEST_CASE("json_view values")
         CHECK(exception_of([&] { static_cast<void>(v.value("s", 0)); }) == without_path(exception_of([&] { static_cast<void>(j.value("s", 0)); })));
         CHECK(exception_of([&] { static_cast<void>(v["n"].value("x", 0)); }) == without_path(exception_of([&] { static_cast<void>(j["n"].value("x", 0)); })));
         CHECK(exception_of([&] { static_cast<void>(v["n"].value(json::json_pointer("/x"), 0)); }) == without_path(exception_of([&] { static_cast<void>(j["n"].value(json::json_pointer("/x"), 0)); })));
-        // string defaults: the member is not a string, or the value is neither an object nor an array
-        CHECK(exception_of([&] { static_cast<void>(v.value("n", "default")); }) == without_path(exception_of([&] { static_cast<void>(j.value("n", "default")); })));
-        CHECK(exception_of([&] { static_cast<void>(v["n"].value("x", "default")); }) == without_path(exception_of([&] { static_cast<void>(j["n"].value("x", "default")); })));
-        CHECK(exception_of([&] { static_cast<void>(v.value(json::json_pointer("/n"), "default")); }) == without_path(exception_of([&] { static_cast<void>(j.value(json::json_pointer("/n"), "default")); })));
-        CHECK(exception_of([&] { static_cast<void>(v["s"].value(json::json_pointer("/x"), "default")); }) == without_path(exception_of([&] { static_cast<void>(j["s"].value(json::json_pointer("/x"), "default")); })));
 #endif
-        // (defaults and members longer than the short string optimization)
-        CHECK(v.value("s", "a default longer than fifteen characters") == "text");
-        CHECK(v.value("missing", "a default longer than fifteen characters") == "a default longer than fifteen characters");
-        CHECK(v.value(json::json_pointer("/s"), "a default longer than fifteen characters") == "text");
-        CHECK(v.value(json::json_pointer("/zz"), "a default longer than fifteen characters") == "a default longer than fifteen characters");
     }
 }
 

tests/src/unit-json_view_builder.cpp

@@ -523,58 +523,6 @@ TEST_CASE("json_view builder: strings across vector blocks")
     }
 }
 
-TEST_CASE("json_view builder: escapes between runs of text")
-{
-    // The text between escapes is copied 16 bytes at a time where there are
-    // that many bytes left, and with the UTF-8 check where there is
-    // non-ASCII text. Runs of every length from 0 to 40 between valid and
-    // invalid escapes, UTF-8 sequences, and control characters, in strings
-    // that are cut at all places near the end of the text.
-    const std::array<const char*, 9> valid = {{"\\n", "\\\"", "\\\\", "\\/", "\\t", "\\u00e4", "\\u20ac", "\\ud83d\\ude00", "\\u0000"}};
-    const std::array<const char*, 9> invalid = {{"\\x", "\\ud800", "\\udc00", "\\u12G4", "\\u12", "\\ud83dx", "\\ud83d\\u0041", "\\", "\x01"}};
-    const std::array<const char*, 6> utf8 = {{"\xc3\xa4", "\xe2\x82\xac", "\xf0\x9f\x98\x80", "\xc3", "\xff", "\x80"}};
-    std::mt19937 rng(2026); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed): reproducible
-    for (std::size_t run = 0; run <= 40; ++run)
-    {
-        for (int i = 0; i < 60; ++i)
-        {
-            std::string content = std::string(rng() % 20, 'a');
-            const auto pieces = 1 + (rng() % 6);
-            for (unsigned k = 0; k < pieces; ++k)
-            {
-                content += valid[rng() % valid.size()];
-                content += std::string(k == 0 ? run : rng() % 41, static_cast<char>('b' + (rng() % 20)));
-                switch (rng() % 8)
-                {
-                    case 0:
-                        content += utf8[rng() % 3];
-                        break;
-                    case 1:
-                        content += utf8[rng() % utf8.size()];
-                        break;
-                    case 2:
-                        content += invalid[rng() % invalid.size()];
-                        break;
-                    default:
-                        break;
-                }
-            }
-            check_string(content);
-            check_string(content.substr(0, content.size() - (rng() % 4)));
-        }
-    }
-    // the text before the first escape, and runs and escapes at the end of the text
-    for (std::size_t before = 0; before <= 40; ++before)
-    {
-        for (const char* escape : valid)
-        {
-            check_string(std::string(before, 'a') + escape);
-            check_string(std::string(before, 'a') + escape + std::string(before % 19, 'z'));
-            check_string(std::string(before, 'a') + escape + escape + std::string(before % 19, 'z'));
-        }
-    }
-}
-
 TEST_CASE("json_view node integer bits")
 {
     using nlohmann::detail::view::integer_bits;

tests/src/unit-json_view_dump.cpp

@@ -21,7 +21,6 @@ using nlohmann::ordered_json_view;
 using json_view_test::generator;
 using json_view_test::has_duplicate_keys;
 
-#include <algorithm>
 #include <array>
 #include <cmath>
 #include <cstddef>
@@ -30,7 +29,6 @@ using json_view_test::has_duplicate_keys;
 #include <iomanip>
 #include <map>
 #include <random>
-#include <set>
 #include <sstream>
 #include <string>
 #include <vector>
@@ -600,142 +598,6 @@ TEST_CASE("json_view large objects")
         CHECK(without_collisions.memory_usage() >= with_collisions.memory_usage() + (table_size * sizeof(std::uint32_t)));
     }
 
-    SECTION("keys that differ in their last bytes are spread over the table")
-    {
-        // The hash must spread the usual families of keys (numbered names, hex
-        // strings, dates, short names): a key farther than index_max_displacement
-        // from its home slot would leave the object without a table. The keys
-        // are placed with linear probing, as the table does.
-        const auto max_displacement = [](const std::vector<std::string>& keys)
-        {
-            std::size_t slots = 16;
-            while (slots < 2 * keys.size())
-            {
-                slots *= 2;
-            }
-            std::vector<bool> used(slots, false);
-            std::size_t farthest = 0;
-            for (const std::string& key : keys)
-            {
-                std::size_t i = static_cast<std::size_t>(nlohmann::detail::view::key_hash(key.data(), key.size())) & (slots - 1);
-                std::size_t distance = 0;
-                while (used[i])
-                {
-                    i = (i + 1) & (slots - 1);
-                    ++distance;
-                }
-                used[i] = true;
-                farthest = (std::max)(farthest, distance);
-            }
-            return farthest;
-        };
-        // the keys of a printf-like pattern with one %d, %0Nd or %0Nx, formatted with a stream
-        // (a format string that is not a literal is a Flawfinder error)
-        const auto numbered = [](const char* format, int count, int step)
-        {
-            const std::string pattern(format);
-            const std::size_t percent = pattern.find('%');
-            std::size_t conversion = percent + 1;
-            std::size_t width = 0;
-            while (pattern[conversion] >= '0' && pattern[conversion] <= '9')
-            {
-                width = width * 10 + static_cast<std::size_t>(pattern[conversion] - '0');
-                ++conversion;
-            }
-            const bool hex = pattern[conversion] == 'x';
-            std::vector<std::string> keys;
-            for (int i = 0; i < count; ++i)
-            {
-                std::ostringstream key;
-                key << pattern.substr(0, percent) << std::setfill('0') << std::setw(static_cast<int>(width))
-                    << (hex ? std::hex : std::dec) << i * step << pattern.substr(conversion + 1);
-                keys.push_back(key.str());
-            }
-            return keys;
-        };
-        for (const char* format :
-                {"key%d", "%d", "item_%04d", "a%05d", "%03dxyz", "id%d", "user_%d", "%d_suffix", "0x%04x", "A%07d", "12345678%d", "1234567%d", "123456789%d",
-                 "configuration_parameter_value_%04d_extra", "2026-01-%02dT00:00:00Z"
-                })
-        {
-            CAPTURE(format)
-            CHECK(max_displacement(numbered(format, std::string(format).find("%02d") != std::string::npos ? 60 : 1000, 1)) < nlohmann::detail::view::index_max_displacement);
-            CHECK(max_displacement(numbered(format, 600, 7)) < nlohmann::detail::view::index_max_displacement);
-        }
-        std::mt19937_64 rng(7);
-        for (const std::size_t length :
-                {
-                    std::size_t{1}, std::size_t{2}, std::size_t{3}, std::size_t{5}, std::size_t{7}, std::size_t{8}, std::size_t{9}, std::size_t{12}, std::size_t{16}, std::size_t{17}, std::size_t{33}
-                })
-        {
-            CAPTURE(length)
-            std::set<std::string> distinct;
-            while (distinct.size() < (length == 1 ? 26 : (length == 2 ? 500 : 700))) // (there are 26 and 676 keys of one and two letters)
-            {
-                std::string key(length, 'a');
-                for (char& c : key)
-                {
-                    c = static_cast<char>('a' + (rng() % 26));
-                }
-                distinct.insert(key);
-            }
-            CHECK(max_displacement(std::vector<std::string>(distinct.begin(), distinct.end())) < nlohmann::detail::view::index_max_displacement);
-        }
-    }
-
-    SECTION("keys of every length that differ in one byte")
-    {
-        // In a large object, a key is found by comparing its bytes with those of the member the
-        // table points to: up to 16 bytes as two overlapping words, longer ones with memcmp.
-        // Keys of every length from 0 to 40, and keys that differ from them in one byte.
-        std::mt19937_64 rng(2026);
-        std::vector<std::string> keys;
-        std::set<std::string> distinct;
-        for (std::size_t length = 0; length <= 40; ++length)
-        {
-            for (int copy = 0; copy < 5; ++copy)
-            {
-                std::string key(length, 'a');
-                for (char& c : key)
-                {
-                    c = static_cast<char>('a' + (rng() % 26));
-                }
-                if (distinct.insert(key).second)
-                {
-                    keys.push_back(key);
-                }
-            }
-        }
-        std::string text = "{";
-        for (std::size_t i = 0; i < keys.size(); ++i)
-        {
-            text += (i != 0 ? ",\"" : "\"") + keys[i] + "\":" + std::to_string(i);
-        }
-        text += "}";
-        REQUIRE(keys.size() >= 128); // (a table is built for 128 members)
-        const json_document d = json_document::parse(text);
-        const json_view v = d.root();
-        for (std::size_t i = 0; i < keys.size(); ++i)
-        {
-            CAPTURE(keys[i])
-            CHECK(v[keys[i]].get<std::size_t>() == i);
-            CHECK(v.at(keys[i]).get<std::size_t>() == i);
-            CHECK(v.contains(keys[i]));
-            for (std::size_t at = 0; at < keys[i].size(); ++at)
-            {
-                std::string other = keys[i];
-                other[at] = other[at] == 'z' ? 'y' : 'z';
-                CAPTURE(other)
-                CHECK(v.contains(other) == (distinct.count(other) != 0));
-            }
-            CHECK(v.contains(keys[i] + "a") == (distinct.count(keys[i] + "a") != 0));
-            if (!keys[i].empty())
-            {
-                CHECK(v.contains(keys[i].substr(1)) == (distinct.count(keys[i].substr(1)) != 0));
-            }
-        }
-    }
-
     SECTION("shrink_to_fit releases the tables' spare capacity")
     {
         const auto make_text = [](int objects, int members)

tests/src/unit-json_view_edit.cpp

@@ -661,115 +661,6 @@ TEST_CASE("json_view edits: replacing arrays and objects by scalars")
     CHECK(d.root().materialize() == expected);
 }
 
-TEST_CASE("json_view edits: arrays whose elements have no subtrees")
-{
-    // such an array is indexed directly while it is in its parsed layout; edits
-    // that replace elements by scalars keep it, others move it
-    json_editable_document d = json_editable_document::parse("[10,20,30,40]");
-    json expected = json::array({10, 20, 30, 40});
-    const auto check = [&]
-    {
-        CHECK(d.root().size() == expected.size());
-        for (std::size_t i = 0; i < expected.size(); ++i)
-        {
-            CHECK(d.root()[i].materialize() == expected[i]);
-            CHECK(d.root().at(i).materialize() == expected[i]);
-        }
-        CHECK(d.root()[expected.size()].is_discarded());
-        CHECK(d.root().back().materialize() == expected.back());
-        CHECK(d.root().dump() == expected.dump());
-    };
-    check();
-    d.set(d.root()[1], "x");
-    expected[1] = "x";
-    check();
-    d.set(d.root()[3], 2.5);
-    expected[3] = 2.5;
-    check();
-    d.set(d.root()[2], json::array({1, 2}));
-    expected[2] = json::array({1, 2});
-    check();
-    d.push_back(d.root(), 50);
-    expected.push_back(50);
-    check();
-    d.insert(d.root(), 0, true);
-    expected.insert(expected.begin(), true);
-    check();
-    d.erase(d.root(), 1);
-    expected.erase(expected.begin() + 1);
-    check();
-    d.set(d.root()[2], nullptr);
-    expected[2] = nullptr;
-    check();
-}
-
-TEST_CASE("json_view edits: materializing values nested deeper than the document was parsed")
-{
-    // the stack of open containers of materialize() is sized from the nesting of the parsed text;
-    // a value added by an edit can be deeper than that (and than the stack that is local to the call)
-    json_editable_document d = json_editable_document::parse("[1,[2]]");
-    json expected = json::array({1, json::array({2})});
-    json nested = 3;
-    for (int level = 0; level < 40; ++level)
-    {
-        nested = json::array({nested, json{{"k", level}}});
-    }
-    d.push_back(d.root(), nested);
-    expected.push_back(nested);
-    CHECK(d.root().materialize() == expected);
-    CHECK(d.root()[2].materialize() == nested);
-    d.set(d.root()[1][0], nested);
-    expected[1][0] = nested;
-    CHECK(d.root().materialize() == expected);
-    CHECK(d.root().get<json>() == expected);
-}
-
-TEST_CASE("json_view edits: an editable document before and after its first edit")
-{
-    // until the first edit, an editable document is read like a read-only one; views made before the edit
-    // keep working after it
-    const std::string text = R"({"a":[1,2,{"x":"y"},4],"b":{"c":true,"d":null},"e":"text","f":[]})";
-    const json_document read_only = json_document::parse(text);
-    json_editable_document d = json_editable_document::parse(text);
-    const auto root = d.root();
-    const auto same_as_read_only = [&]
-    {
-        CHECK(root.dump() == read_only.root().dump());
-        CHECK(root.dump(2) == read_only.root().dump(2));
-        CHECK(root.materialize() == read_only.root().materialize());
-        CHECK(root["a"][2]["x"].get_string() == "y");
-        CHECK(root["a"].at(3).get<int>() == 4);
-        CHECK(root["a"].back().get<int>() == 4);
-        CHECK(root.contains("b"));
-        CHECK(!root.contains("zz"));
-        CHECK(root.find("e")->get_string() == "text");
-        CHECK(root.find("zz") == root.end());
-        CHECK(root["b"]["c"].get<bool>());
-        CHECK(root.value("e", "none") == "text");
-        std::size_t count = 0;
-        for (const auto m : root["a"])
-        {
-            CHECK(m.materialize() == read_only.root()["a"][count].materialize());
-            ++count;
-        }
-        CHECK(count == 4);
-    };
-    same_as_read_only();
-    // an edit that changes a scalar in place, then one that moves an array
-    d.set(root["e"], "other");
-    CHECK(root["e"].get_string() == "other");
-    CHECK(root["a"][2]["x"].get_string() == "y");
-    CHECK(root["a"].back().get<int>() == 4);
-    d.push_back(root["f"], 7);
-    CHECK(root["f"][0].get<int>() == 7);
-    CHECK(root["f"].back().get<int>() == 7);
-    CHECK(root.dump() == R"({"a":[1,2,{"x":"y"},4],"b":{"c":true,"d":null},"e":"other","f":[7]})");
-    d.set(root["a"], 2, json::array({1, 2}));
-    CHECK(root["a"][2][1].get<int>() == 2);
-    CHECK(root["a"].dump() == "[1,2,[1,2],4]");
-    CHECK(root.materialize() == json::parse(R"({"a":[1,2,[1,2],4],"b":{"c":true,"d":null},"e":"other","f":[7]})"));
-}
-
 namespace
 {
 // reads of "a" in an object that repeats it: the first member wins, however the