Merge develop

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Merge branch 'develop' into claude/json-view-canada-perf-99bbe3
2026-10-27 16:28:57 +00:00 · 2026-10-27 14:31:51 +01:00 · 2026-10-27 07:29:22 +01:00 · 2026-10-26 21:41:12 +01:00 · 2026-10-26 15:53:28 +01:00 · 2026-10-26 06:54:53 +01:00
21 changed files with 2097 additions and 1732 deletions
@@ -32,20 +32,9 @@ uses, so the result matches it exactly — including, for an object, that a repe
 last value. The replay is iterative, so it is not limited by the call stack the way a naive recursive conversion
 would be; the JSON nesting depth is limited only by available memory, as for `BasicJsonType::parse()` itself.

-With [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) enabled, the values get the source
-positions [`BasicJsonType::parse()`](../basic_json/parse.md) would give them, also for the subtree of a view (the
-positions are those in the document's whole source text), and exceptions about them name the same bytes. For values of
-an [editable document](../json_editable_document.md), positions are all-or-nothing, and [`start_pos()`](../basic_json/start_pos.md)
-and [`end_pos()`](../basic_json/end_pos.md) return `std::string::npos` for
-
- a value written by an edit (a copy of an array or object of the document is also new; copies of its scalars keep
-  their positions),
- an array or object whose elements were changed (its elements keep theirs), and
- an array or object whose last element has no positions (its end is found from that element).
-
-A `basic_json` value, in contrast, keeps its positions when it is changed. Documents [loaded](../basic_json_document/load.md)
-from an image have the positions of the saved document, except that its strings with escapes have none if it was saved
-without `JSON_DIAGNOSTIC_POSITIONS`.
+Unlike parsing with [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) enabled, the values
+produced by `materialize()` do not carry source positions. The index has the start offset of every value, but not the
+end of arrays, objects, and escaped strings, which the positions also need.

 Calling `materialize()` on the same view repeatedly builds a new, independent `BasicJsonType` value each time; it
 never caches the result.
@@ -73,7 +62,8 @@ never caches the result.

 - [`root`](../basic_json_document/root.md) - the view of a document's root value
 - [`BasicJsonType::parse`](../basic_json/parse.md) - build a `BasicJsonType` value directly from a JSON text
- [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) - source positions on parsed values
+- [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) - source positions on parsed values (not
+  produced by `materialize()`)
 - [Zero-copy JSON views](../../features/json_view.md#getting-values-out-without-copying) - when to build a basic_json value from a view

 ## Version history
@@ -113,7 +113,6 @@ When the macro is not defined, the library will define it to its default value.

 - [:simple-cmake: JSON_Diagnostic_Positions](../../integration/cmake.md#json_diagnostic_positions) - CMake option to control the macro
 - [`JSON_DIAGNOSTICS`](json_diagnostics.md) - macro to control extended diagnostics
- [`materialize()`](../basic_json_view/materialize.md) - values of a JSON view, with the same positions
 - [Parsing and Exceptions](../../features/parsing/parse_exceptions.md) - handling parse errors and locating them in the input

 ## Version history
@@ -149,12 +149,10 @@ document: `#!cpp auto v = json_document::parse(text).root();` does not compile.
  end must still fit.
 - **A stream is always read to its end.** There is no partial/streaming read of an `#!cpp std::istream`: the stream
  is read to its end into a buffer the document owns, and parsing starts after that.
- **Fewer source positions after edits.** With
+- **No source positions on `materialize()`.** Even with
  [`JSON_DIAGNOSTIC_POSITIONS`](../api/macros/json_diagnostic_positions.md) enabled,
-  [`materialize()`](../api/basic_json_view/materialize.md) sets the same positions as `#!cpp basic_json::parse()`.
-  In an [editable document](../api/json_editable_document.md), a value written by an edit has none, and neither has
-  an array or object whose elements changed or whose last element has none; a `basic_json` value keeps its positions
-  when it is changed. See [`materialize()`](../api/basic_json_view/materialize.md#notes).
+  [`materialize()`](../api/basic_json_view/materialize.md) does not set them. The index has the start offset of every
+  value, but not the end of arrays, objects, and escaped strings, which the positions also need.
 - **Objects iterate in document order.** [`begin()`](../api/basic_json_view/begin.md)/
  [`end()`](../api/basic_json_view/end.md) and [`items()`](../api/basic_json_view/items.md) visit an object's
  members in the order they appear in the source text. `basic_json`'s default `object_t` is a `std::map`, which
@@ -203,7 +203,7 @@ packet-beta
 | 2-3   | `extra` | `uint16_t` | numbers: the number of integer digits (low byte) and fraction digits (high byte), 255 for more; objects: the number of their key hash index (1-based), or 0; otherwise 0 |
 | 4-7   | `off`   | `uint32_t` | where the value starts: the first byte after a string's opening quote (or its position in the buffer of decoded strings), the first byte of a number or literal, the bracket of an array or object |
 | 8-11  | `len`   | `uint32_t` | strings: the length after decoding; floats and literals: the length of the token; arrays and objects: the number of elements |
-| 12-15 | `next`  | `uint32_t` | arrays and objects: the number of nodes of the subtree, including the node itself; strings with escapes: the position of the opening quote in the source plus one, or 0 (only with [`JSON_DIAGNOSTIC_POSITIONS`](../api/macros/json_diagnostic_positions.md)) |
+| 12-15 | `next`  | `uint32_t` | arrays and objects: the number of nodes of the subtree, including the node itself                                              |

 <p class="nj-table-caption" markdown>Fields of a node, by their byte offset within the 16-byte node. Integers use bytes 8-15 differently, see below.</p>

@@ -218,11 +218,6 @@ packet-beta
  step from element to element this way and skip whole subtrees in constant time.
 - **Offsets** are 32 bits wide, so a document is limited to 4294967279 bytes, 4 GiB minus 16 bytes (a margin below
  2^32 for positions one scanner step past the end of the text; `out_of_range.416`).
- **Source positions** ([`JSON_DIAGNOSTIC_POSITIONS`](../api/macros/json_diagnostic_positions.md)) are derived by
-  [`materialize()`](../api/basic_json_view/materialize.md) and cost nothing while parsing: a scalar's range follows
-  from `off` and its length, a string with escapes is scanned from its opening quote (`next`) to the closing one,
-  and the end of an array or object is found by scanning from the end of its last element over whitespace, comments,
-  and a trailing comma. `materialize()` hands these positions to the SAX builder of `parse()` in place of its lexer.
 - **Large objects** (128 members or more) get a hash index for their keys after parsing
  ([`detail/view/object_index.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/view/object_index.hpp)):
  an open-addressing table whose slots hold the distance from the object's node to a key's node, so that a lookup does
@@ -282,7 +277,7 @@ Images ([`save`](../api/basic_json_document/save.md) and [`load`](../api/basic_j
 the nodes as they are: a 64-byte header (the magic bytes `NJVI`, a format version, the sizes, and reserved bytes that
 must be zero), the nodes, the text, and the decoded strings. An edited document is first written in document order, as
 the parser would have written it (without links), and the numbers of the hash indexes are cleared, since `load`
-rebuilds the indexes. The flag *new* is kept, as these values have no position in the text. So a change of the node layout is a change of the image format: it must raise `image_version`,
+rebuilds the indexes. So a change of the node layout is a change of the image format: it must raise `image_version`,
 and `load` then rejects images of other versions (`parse_error.116`) instead of misreading them.

 ## Input adapters
@@ -230,10 +230,7 @@ struct diagnostic_positions
        {
            // Lexer has read the first character of the container, so
            // subtract 1 from the position to get the correct start position.
-            // (npos: a value without a source position, see materialize() of
-            // json_view)
-            const std::size_t read = lexer->get_chars_read_total();
-            v.start_position = read == std::string::npos ? read : read - 1;
+            v.start_position = lexer->get_chars_read_total() - 1;
        }
    }

@@ -248,12 +245,6 @@ struct diagnostic_positions
        {
            // Lexer's position is past the closing brace or bracket, so set that as the end position.
            v.end_position = lexer->get_chars_read_total();
-            if (v.end_position == std::string::npos)
-            {
-                // a range has both ends or none (exception::diagnostics()
-                // prints only complete ones)
-                v.start_position = v.end_position;
-            }
        }
    }

@@ -270,12 +261,6 @@ struct diagnostic_positions
            // The start position will be set below based on the length of the string representation
            // of the value.
            v.end_position = lexer->get_chars_read_total();
-            if (v.end_position == std::string::npos)
-            {
-                // a value without a source position
-                v.start_position = v.end_position;
-                return;
-            }

            switch (v.type())
            {
@@ -488,12 +473,8 @@ read up to it.
@tparam Collect  whether to collect the values of containers of unknown size on
                 a stack (only for a caller that does not use the value after a
                 parse error)
-@tparam LexerType  the type of the lexer that reports the source positions
-                   (JSON_DIAGNOSTIC_POSITIONS); only diagnostic_positions uses
-                   it, so any type with its three functions works (as
-                   materialize() of json_view uses it)
 */
-template<typename BasicJsonType, typename InputAdapterType, bool Collect = false, typename LexerType = lexer<BasicJsonType, InputAdapterType>>
+template<typename BasicJsonType, typename InputAdapterType, bool Collect = false>
 class json_sax_dom_parser : public json_sax_dom_error_state
 {
  public:
@@ -502,7 +483,7 @@ class json_sax_dom_parser : public json_sax_dom_error_state
    using number_float_t = typename BasicJsonType::number_float_t;
    using string_t = typename BasicJsonType::string_t;
    using binary_t = typename BasicJsonType::binary_t;
-    using lexer_t = LexerType;
+    using lexer_t = lexer<BasicJsonType, InputAdapterType>;

    /*!
    @param[in,out] r  reference to a JSON value that is manipulated while
@@ -56,8 +56,8 @@ using parser_callback_t =
 template<typename SAX>
 struct sax_ignores_number_text : std::false_type {};

-template<typename BasicJsonType, typename InputAdapterType, bool Collect, typename LexerType>
-struct sax_ignores_number_text<json_sax_dom_parser<BasicJsonType, InputAdapterType, Collect, LexerType>> : std::true_type {};
+template<typename BasicJsonType, typename InputAdapterType, bool Collect>
+struct sax_ignores_number_text<json_sax_dom_parser<BasicJsonType, InputAdapterType, Collect>> : std::true_type {};

 template<typename BasicJsonType, typename InputAdapterType>
 struct sax_ignores_number_text<json_sax_dom_callback_parser<BasicJsonType, InputAdapterType>> : std::true_type {};
@@ -1193,13 +1193,7 @@ indent_done:
                return false;
            }
            p = r.p;
-#if JSON_DIAGNOSTIC_POSITIONS
-            // the decoded string is in the arena: next keeps the source offset
-            // of the opening quote plus one (0: unknown) for materialize()
-            push_node(node_kind::string, node_flags::escaped, 0, r.start, static_cast<std::uint64_t>(r.len) | (static_cast<std::uint64_t>(s - b) << 32));
-#else
            push_node(node_kind::string, node_flags::escaped, 0, r.start, r.len);
-#endif
            return true;
        }
    };
@@ -80,8 +80,7 @@ constexpr std::uint64_t image_limit = 0xFFFFFFF0u;
 /// Copy the current structure of an edited document into nodes in document
 /// order, as the parser would have written them. Text written by edits is
 /// appended to text_tail (number tokens) and arena_tail (strings); floats that
-/// are not finite become null, as dump() writes them. Nodes keep the flag
-/// is_new: they have no source position (JSON_DIAGNOSTIC_POSITIONS).
+/// are not finite become null, as dump() writes them.
 inline void compact_nodes(const document_data& d, std::size_t arena_size, std::vector<node>& out, std::string& text_tail, std::string& arena_tail)
 {
    struct frame
@@ -104,18 +103,16 @@ inline void compact_nodes(const document_data& d, std::size_t arena_size, std::v
            arena_tail.append(d.str(s), s.len);
            r.flags = node_flags::escaped;
        }
-        r.flags = static_cast<std::uint8_t>(r.flags | (s.flags & node_flags::is_new));
        return r;
    };
    const auto copy_node = [&](const node * v)
    {
        node r = *v;
-        const auto is_new = static_cast<std::uint8_t>(v->flags & node_flags::is_new);
        switch (static_cast<value_t>(v->kind))
        {
            case value_t::object:
            case value_t::array:
-                r.flags = is_new;
+                r.flags = 0;
                r.extra = 0;
                r.off = (v->flags & (node_flags::moved | node_flags::is_new)) != 0 ? 0 : v->off;
                r.len = 0;  // counted below
@@ -132,7 +129,7 @@ inline void compact_nodes(const document_data& d, std::size_t arena_size, std::v
                    r.off = static_cast<std::uint32_t>(d.size + text_tail.size());
                    text_tail.append(d.str(*v), number_length(*v));
                }
-                r.flags = is_new;
+                r.flags = 0;
                break;
            case value_t::number_float:
                if ((v->flags & node_flags::storage) == node_flags::edited)
@@ -142,23 +139,22 @@ inline void compact_nodes(const document_data& d, std::size_t arena_size, std::v
                    {
                        r = node{}; // nan and infinity: null, as dump() writes them
                        r.kind = node_kind::null;
-                        r.flags = is_new;
                        break;
                    }
                    r.off = static_cast<std::uint32_t>(d.size + text_tail.size());
                    text_tail.append(t, v->len);
                    r.extra = 0xFFFFu; // the digit layout is not recorded
                }
-                r.flags = is_new;
+                r.flags = 0;
                break;
            case value_t::boolean:
-                r.flags = static_cast<std::uint8_t>(v->flags & (node_flags::is_true | node_flags::is_new));
+                r.flags = static_cast<std::uint8_t>(v->flags & node_flags::is_true);
                break;
            case value_t::null:
            case value_t::binary:
            case value_t::discarded:
            default:
-                r.flags = is_new;
+                r.flags = 0;
                break;
        }
        out.push_back(r);
@@ -519,15 +515,13 @@ inline bool check_image(const node* nodes, std::size_t count, const unsigned cha
    std::vector<float_range> floats;
    const auto check_string = [&](const node & n) -> bool
    {
-        if ((n.flags & ~(node_flags::escaped | node_flags::is_new)) != 0 || n.extra != 0)
+        if ((n.flags & ~node_flags::escaped) != 0 || n.extra != 0)
        {
            return false;
        }
        const bool decoded = (n.flags & node_flags::escaped) != 0;
        const std::size_t limit = decoded ? arena_size : text_size;
-        // (next: the source offset of a decoded string's opening quote plus
-        // one, or 0; see node)
-        if (n.off > limit || n.len > limit - n.off || n.next > text_size)
+        if (n.off > limit || n.len > limit - n.off)
        {
            return false;
        }
@@ -599,13 +593,13 @@ inline bool check_image(const node* nodes, std::size_t count, const unsigned cha
        {
            case value_t::null:
                // (the offset of a literal is read to size the output of dump())
-                if ((n.flags & ~node_flags::is_new) != 0 || n.extra != 0 || n.off > text_size)
+                if (n.flags != 0 || n.extra != 0 || n.off > text_size)
                {
                    return false;
                }
                break;
            case value_t::boolean:
-                if ((n.flags & ~(node_flags::is_true | node_flags::is_new)) != 0 || n.extra != 0 || n.off > text_size)
+                if ((n.flags & ~node_flags::is_true) != 0 || n.extra != 0 || n.off > text_size)
                {
                    return false;
                }
@@ -619,7 +613,7 @@ inline bool check_image(const node* nodes, std::size_t count, const unsigned cha
            case value_t::number_integer:
            case value_t::number_unsigned:
            case value_t::number_float:
-                if ((n.flags & ~node_flags::is_new) != 0 || !number_in_bounds(n))
+                if (n.flags != 0 || !number_in_bounds(n))
                {
                    return false;
                }
@@ -641,7 +635,7 @@ inline bool check_image(const node* nodes, std::size_t count, const unsigned cha
            case value_t::object:
            {
                const std::size_t limit = stack.empty() ? count : stack.back().end;
-                if ((n.flags & ~node_flags::is_new) != 0 || n.extra != 0 || n.next == 0 || n.next > limit - i || n.off > text_size)
+                if (n.flags != 0 || n.extra != 0 || n.next == 0 || n.next > limit - i || n.off > text_size)
                {
                    return false;
                }
@@ -26,176 +26,6 @@ namespace detail
 namespace view
 {

-#if JSON_DIAGNOSTIC_POSITIONS
-/*!
-@brief the source positions of the values materialize() replays
-
-Stands in for the lexer of json_sax_dom_parser, which reads the positions of
-the values it stores from these three functions (diagnostic_positions). npos
-is a value without a source position.
-*/
-struct position_source
-{
-    /// the token, of which diagnostic_positions only reads the length
-    struct token
-    {
-        std::size_t length;
-        std::size_t size() const noexcept
-        {
-            return length;
-        }
-    };
-
-    std::size_t start = std::string::npos; ///< the first byte of the next value
-    std::size_t end = std::string::npos;   ///< one past the next value (start_object/start_array: one past the bracket)
-
-    std::size_t get_chars_read_total() const noexcept
-    {
-        return end;
-    }
-    std::size_t get_token_start_position() const noexcept
-    {
-        return start;
-    }
-    token get_string() const noexcept
-    {
-        return token{end - start};
-    }
-
-    /// the range [first, last), or none if either is npos
-    void set(std::size_t first, std::size_t last) noexcept
-    {
-        const bool known = first != std::string::npos && last != std::string::npos;
-        start = known ? first : std::string::npos;
-        end = known ? last : std::string::npos;
-    }
-
-    /// one past the closing quote of the string whose opening quote is at
-    /// src[quote], or npos (the scan is bounded by size, as images can be
-    /// loaded without a check)
-    static std::size_t string_end(const char* src, std::size_t size, std::size_t quote) noexcept
-    {
-        for (std::size_t i = quote + 1; i < size; ++i)
-        {
-            if (src[i] == '\\')
-            {
-                ++i;
-            }
-            else if (src[i] == '"')
-            {
-                return i + 1;
-            }
-        }
-        return std::string::npos;
-    }
-
-    /// one past the closing bracket of the array or object whose last element
-    /// ends at src[pos] (or whose opening bracket is at src[pos - 1]), or npos;
-    /// in between, there can only be whitespace, comments, and a trailing comma
-    /// (the source was validated when it was parsed)
-    static std::size_t container_end(const char* src, std::size_t size, std::size_t pos) noexcept
-    {
-        while (pos < size)
-        {
-            switch (src[pos])
-            {
-                case ' ':
-                case '\t':
-                case '\n':
-                case '\r':
-                case ',':
-                    ++pos;
-                    break;
-                case ']':
-                case '}':
-                    return pos + 1;
-                case '/':
-                    if (pos + 1 < size && src[pos + 1] == '/')
-                    {
-                        pos += 2;
-                        while (pos < size && src[pos] != '\n' && src[pos] != '\r')
-                        {
-                            ++pos;
-                        }
-                        break;
-                    }
-                    if (pos + 1 < size && src[pos + 1] == '*')
-                    {
-                        pos += 2;
-                        while (pos < size && !(src[pos] == '*' && pos + 1 < size && src[pos + 1] == '/'))
-                        {
-                            ++pos;
-                        }
-                        pos += 2;
-                        break;
-                    }
-                    return std::string::npos;
-                default:
-                    return std::string::npos;
-            }
-        }
-        return std::string::npos;
-    }
-
-    /// the range of the scalar n of document d
-    void set_scalar(const document_data& d, const node& n) noexcept
-    {
-        const std::size_t size = d.size;
-        const std::size_t off = n.off;
-        std::size_t first = std::string::npos;
-        std::size_t last = std::string::npos;
-        if ((n.flags & node_flags::is_new) == 0)
-        {
-            switch (static_cast<value_t>(n.kind))
-            {
-                case value_t::string:
-                    if ((n.flags & node_flags::storage) == 0)
-                    {
-                        // off is the first byte after the opening quote
-                        if (off != 0)
-                        {
-                            first = off - 1;
-                            last = off + std::size_t{n.len} + 1;
-                        }
-                    }
-                    else if ((n.flags & node_flags::storage) == node_flags::escaped && n.next != 0)
-                    {
-                        // next is the offset of the opening quote plus one
-                        first = n.next - 1;
-                        last = string_end(d.base[0], size, first);
-                    }
-                    break;
-                case value_t::number_integer:
-                case value_t::number_unsigned:
-                case value_t::number_float:
-                    if ((n.flags & node_flags::storage) == 0)
-                    {
-                        first = off;
-                        last = off + number_length(n);
-                    }
-                    break;
-                case value_t::boolean:
-                    first = off;
-                    last = off + ((n.flags & node_flags::is_true) != 0 ? 4u : 5u);
-                    break;
-                case value_t::null:
-                    first = off;
-                    last = off + 4u;
-                    break;
-                case value_t::object:
-                case value_t::array:
-                case value_t::binary:
-                case value_t::discarded:
-                default:
-                    break;
-            }
-        }
-        // (a crafted image can point past the text)
-        set(first, last != std::string::npos && last <= size ? last : std::string::npos);
-    }
-};
-#endif
-
 /*!
@brief the basic_json value of the subtree at n

@@ -203,22 +33,14 @@ The subtree is replayed into the SAX handler that parse() uses to build its
 values, so the result is the value parse() would produce: duplicate keys keep
 the last value, and with JSON_DIAGNOSTICS the parent pointers are set. It is
 iterative, so the nesting depth is limited by memory only, as for parse().
-
-With JSON_DIAGNOSTIC_POSITIONS, the values get their source positions as with
-parse(): position_source stands in for the lexer. Values written by edits have
-none (npos), and neither has an array or object whose elements changed, or
-whose last element has none (the end of its closing bracket is found by
-scanning from the end of the last element).
+Without a lexer the handler records no source positions
+(JSON_DIAGNOSTIC_POSITIONS).
 */
 template<typename BasicJsonType, bool Editable>
 BasicJsonType materialize(const document_data& d, const node* n)
 {
    using string_t = typename BasicJsonType::string_t;
-#if JSON_DIAGNOSTIC_POSITIONS
-    using sax_t = json_sax_dom_parser<BasicJsonType, iterator_input_adapter<const char*>, true, position_source>;
-#else
    using sax_t = json_sax_dom_parser<BasicJsonType, iterator_input_adapter<const char*>, true>;
-#endif
    using nav = navigation<Editable>;

    // the open containers: their next element (or key of the next member),
@@ -230,15 +52,9 @@ BasicJsonType materialize(const document_data& d, const node* n)
        const node* pos;
        const node* end;
        bool object;
-#if JSON_DIAGNOSTIC_POSITIONS
-        std::size_t start;    ///< the opening bracket (npos: unknown)
-        std::size_t last_end; ///< the end of the last element read (npos: unknown)
-#endif
    };

-#if !JSON_DIAGNOSTIC_POSITIONS
    // a scalar needs neither the handler nor the stack of open containers
-    // (with positions, it goes through the handler, which sets them)
    switch (static_cast<value_t>(n->kind))
    {
        case value_t::string:
@@ -260,16 +76,10 @@ BasicJsonType materialize(const document_data& d, const node* n)
        default:
            break;
    }
-#endif

    BasicJsonType result;
-#if JSON_DIAGNOSTIC_POSITIONS
-    position_source positions;
-    sax_t sax(result, true, &positions);
-#else
    sax_t sax(result, true);
-#endif
-    const string_t no_token {};
+    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{};
@@ -284,16 +94,6 @@ BasicJsonType materialize(const document_data& d, const node* n)
    std::size_t depth = 0;
    for (;;)
    {
-#if JSON_DIAGNOSTIC_POSITIONS
-        if (!is_container(*n))
-        {
-            positions.set_scalar(d, *n);
-            if (depth != 0)
-            {
-                open[depth - 1].last_end = positions.end;
-            }
-        }
-#endif
        // false positive: n comes from nav::value(), which never returns null for a valid index
        // @infer-ignore NULLPTR_DEREFERENCE
        switch (static_cast<value_t>(n->kind))
@@ -302,12 +102,6 @@ BasicJsonType materialize(const document_data& d, const node* n)
            case value_t::array:
            {
                const bool object = n->kind == node_kind::object;
-#if JSON_DIAGNOSTIC_POSITIONS
-                // (moved containers are also new)
-                const std::size_t start = (n->flags & node_flags::is_new) == 0 && n->off < d.size ? std::size_t{n->off} :
-                                          std::string::npos;
-                positions.set(start, start + 1);
-#endif
                if (object)
                {
                    sax.start_object(n->len);
@@ -324,14 +118,8 @@ BasicJsonType materialize(const document_data& d, const node* n)
                    open = deep.data();
                    capacity = deep.size();
                }
-#if JSON_DIAGNOSTIC_POSITIONS
-                // (until an element is read, the container's own bracket is the last thing read)
-                open[depth++] = frame{nav::first(d, n), nav::end(d, n), object, start, positions.end};
+                open[depth++] = frame{nav::first(d, n), nav::end(d, n), object};
                break;
-#else
-                open[depth++] = frame {nav::first(d, n), nav::end(d, n), object};
-                break;
-#endif
            }
            case value_t::string:
            {
@@ -371,15 +159,6 @@ BasicJsonType materialize(const document_data& d, const node* n)
            frame& f = open[depth - 1];
            if (f.pos == f.end)
            {
-#if JSON_DIAGNOSTIC_POSITIONS
-                const std::size_t end = f.start == std::string::npos || f.last_end == std::string::npos ? std::string::npos : position_source::container_end(d.base[0], d.size, f.last_end);
-                // (an end of npos clears the start, see diagnostic_positions)
-                positions.set(end == std::string::npos ? end : end - 1, end);
-                if (depth > 1)
-                {
-                    open[depth - 2].last_end = end;
-                }
-#endif
                if (f.object)
                {
                    sax.end_object();
@@ -69,7 +69,7 @@ struct node
    std::uint16_t extra; ///< numbers: integer digits (low byte) and fraction digits (high byte), 255 = "many"; objects: number of the object's key hash index (1-based, 0 = none); otherwise 0
    std::uint32_t off;   ///< source offset (string content, number token, literal, bracket); arena offset if escaped/edited; number of the element sequence if moved
    std::uint32_t len;   ///< string: decoded bytes; float: token bytes; array/object: element count
-    std::uint32_t next;  ///< array/object: number of nodes of the subtree (its extent in the enclosing sequence); escaped string: source offset of the opening quote plus one (JSON_DIAGNOSTIC_POSITIONS; 0: unknown)
+    std::uint32_t next;  ///< array/object: number of nodes of the subtree (its extent in the enclosing sequence)
 };
 static_assert(sizeof(node) == 16, "node must stay 16 bytes");

@@ -19,6 +19,7 @@
 #include <nlohmann/detail/view/macro_scope.hpp>
 #include <nlohmann/detail/view/node.hpp>
 #include <nlohmann/detail/view/scan.hpp>
+#include <nlohmann/detail/view/simd.hpp>

 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
@@ -103,12 +104,56 @@ NLOHMANN_VIEW_NOINLINE FloatType float_value(const char* first, const node& n)
    return convert_float<FloatType>(first, last, dot, mantissa_end);
 }

+#if NLOHMANN_VIEW_VECTOR
+/*!
+@brief the value of the first 16 digits of a run of digits with a point after
+int_digits of them (or none, if int_digits >= 16)
+
+The 17 bytes at p are read at once: the bytes after the point move down by one,
+then pairs, quadruples, and octets of digits are combined by multiplications
+(after simdjson). The bytes [p, p + 32) must be readable. Bytes that are not
+digits (only in a damaged image loaded with image_check::bounds) give a wrong
+value, but no undefined behavior.
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE std::uint64_t sixteen_digits(const unsigned char* p, unsigned int_digits) noexcept
+{
+#if NLOHMANN_VIEW_NEON
+    const uint8x16_t low = vld1q_u8(p);
+    const uint8x16_t index = vcombine_u8(vcreate_u8(0x0706050403020100u), vcreate_u8(0x0F0E0D0C0B0A0908u));
+    const uint8x16_t before_point = vcltq_u8(index, vdupq_n_u8(static_cast<std::uint8_t>(int_digits)));
+    const uint8x16_t digits = vsubq_u8(vbslq_u8(before_point, low, vextq_u8(low, vld1q_u8(p + 16), 1)), vdupq_n_u8('0'));
+    const uint16x8_t twos = vpaddlq_u8(vmulq_u8(digits, vreinterpretq_u8_u16(vdupq_n_u16(0x010A))));
+    const uint32x4_t fours = vpaddlq_u16(vmulq_u16(twos, vreinterpretq_u16_u32(vdupq_n_u32(0x00010064))));
+    const uint64x2_t eights = vpaddlq_u32(vmulq_u32(fours, vreinterpretq_u32_u64(vdupq_n_u64(0x0000000100002710u))));
+    return (vgetq_lane_u64(eights, 0) * 100000000u) + vgetq_lane_u64(eights, 1);
+#else
+    // NOLINTBEGIN(portability-simd-intrinsics)
+    const __m128i low = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p))); // NOLINT(bugprone-casting-through-void)
+    const __m128i high = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p + 16))); // NOLINT(bugprone-casting-through-void)
+    const __m128i before_point = _mm_cmpgt_epi8(_mm_set1_epi8(static_cast<char>(int_digits)), _mm_setr_epi8(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15));
+    const __m128i moved = _mm_or_si128(_mm_srli_si128(low, 1), _mm_slli_si128(high, 15));
+    const __m128i digits = _mm_sub_epi8(_mm_or_si128(_mm_and_si128(before_point, low), _mm_andnot_si128(before_point, moved)), _mm_set1_epi8('0'));
+    // (16-bit lanes: SSE2 has no multiply-add of bytes)
+    const __m128i tens = _mm_setr_epi16(10, 1, 10, 1, 10, 1, 10, 1);
+    const __m128i twos = _mm_packs_epi32(_mm_madd_epi16(_mm_unpacklo_epi8(digits, _mm_setzero_si128()), tens),
+                                         _mm_madd_epi16(_mm_unpackhi_epi8(digits, _mm_setzero_si128()), tens));
+    const __m128i fours = _mm_madd_epi16(twos, _mm_setr_epi16(100, 1, 100, 1, 100, 1, 100, 1));
+    const __m128i eights = _mm_madd_epi16(_mm_packs_epi32(fours, fours), _mm_setr_epi16(10000, 1, 10000, 1, 10000, 1, 10000, 1));
+    const auto upper = static_cast<std::uint32_t>(_mm_cvtsi128_si32(eights));
+    const auto lower = static_cast<std::uint32_t>(_mm_cvtsi128_si32(_mm_srli_si128(eights, 4)));
+    // NOLINTEND(portability-simd-intrinsics)
+    return (std::uint64_t{upper} * 100000000u) + lower;
+#endif
+}
+#endif
+
 /*!
@brief the digits of a float token with at most 19 digits, from its layout

 The digit layout recorded while parsing says where the integer digits, the
 fraction digits, and the exponent are, so the digits are read eight at a
-time without scanning.
+time without scanning (with SIMD, a token of 16 to 19 digits sixteen at a
+time).

@param[in] p  first character of the token
@param[in] e  end of the token
@@ -118,15 +163,34 @@ NLOHMANN_VIEW_ALWAYS_INLINE float_significand layout_decimal(const unsigned char
 {
    const bool negative = *p == '-';
    p += negative ? 1 : 0;
-    std::uint64_t w = parse_upto19(p, int_digits, limit);
-    p += int_digits;
+    std::uint64_t w = 0;
    std::int64_t q = 0;
-    if (frac_digits != 0)
+#if NLOHMANN_VIEW_VECTOR
+    const unsigned count = int_digits + frac_digits;
+    if (count >= 16 && limit - p >= 32)
    {
-        w = (w * int_pow10(frac_digits)) + parse_upto19(p + 1, frac_digits, limit);
-        p += 1 + frac_digits;
+        // (the point, if any, follows the integer digits; the digits after
+        // the first 16 are at most three)
+        w = sixteen_digits(p, int_digits);
+        for (unsigned i = 16; i < count; ++i)
+        {
+            w = (w * 10) + static_cast<std::uint64_t>(p[i + (i >= int_digits ? 1 : 0)] - '0');
+        }
+        p += count + (frac_digits != 0 ? 1 : 0);
        q = -static_cast<std::int64_t>(frac_digits);
    }
+    else /* NOLINT(readability/braces) */
+#endif
+    {
+        w = parse_upto19(p, int_digits, limit);
+        p += int_digits;
+        if (frac_digits != 0)
+        {
+            w = (w * int_pow10(frac_digits)) + parse_upto19(p + 1, frac_digits, limit);
+            p += 1 + frac_digits;
+            q = -static_cast<std::int64_t>(frac_digits);
+        }
+    }
    if (p != e)
    {
        // [eE][+-]digits; huge exponents saturate (the parser rejected
@@ -161,12 +225,22 @@ NLOHMANN_VIEW_ALWAYS_INLINE float_significand layout_decimal(const unsigned char
 The result is correctly rounded by the lexer's conversion
 (detail::decimal_to_float(): Clinger's fast path where both operands are
 exact, else the Eisel-Lemire algorithm, which needs no fallback for up to 19
-digits), so it is the value parse() produces.
+digits), so it is the value parse() produces. Tokens of 16 or more digits go
+to Eisel-Lemire directly: the fast path takes few of them (none of 17 digits),
+and its check is a branch that data like GeoJSON coordinates mispredicts.
 */
 template<typename FloatType>
 NLOHMANN_VIEW_ALWAYS_INLINE FloatType layout_float(const unsigned char* p, const unsigned char* e, unsigned int_digits, unsigned frac_digits, const unsigned char* limit) noexcept
 {
-    return decimal_to_float<FloatType>(layout_decimal(p, e, int_digits, frac_digits, limit));
+    const float_significand d = layout_decimal(p, e, int_digits, frac_digits, limit);
+    if (int_digits + frac_digits >= 16)
+    {
+        using format = ieee_binary_format<std::numeric_limits<FloatType>::digits>;
+        native_float_t<FloatType> value{};
+        float_from_bits(eisel_lemire<format>(d.exponent, d.w) | (d.negative ? (std::uint64_t{1} << format::sign_bit()) : 0u), value);
+        return value;
+    }
+    return decimal_to_float<FloatType>(d);
 }

 /// the value of a float set by an edit: its token (the shortest round-trip
@@ -185,6 +259,80 @@ NLOHMANN_VIEW_NOINLINE FloatType edited_float(const char* token, const node& n)
    return float_value<FloatType>(token, n);
 }

+#if NLOHMANN_VIEW_VECTOR
+/// eisel_lemire() for the token w * 10^q of coordinate_float()
+template<typename Format>
+NLOHMANN_VIEW_ALWAYS_INLINE std::uint64_t coordinate_bits(std::int64_t q, std::uint64_t w, Format /*format*/) noexcept
+{
+    return eisel_lemire<Format>(q, w);
+}
+
+/*!
+@brief (binary64) eisel_lemire() without the cases that tokens of 16 or 17
+digits with 5 or more after the point cannot reach: a value of 0, a
+subnormal, an infinity, or a tie (q < -4)
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE std::uint64_t coordinate_bits(std::int64_t q, std::uint64_t w, ieee_binary_format<53> format) noexcept
+{
+    if (NLOHMANN_VIEW_UNLIKELY(w == 0 || q > -5))
+    {
+        return eisel_lemire<ieee_binary_format<53>>(q, w);
+    }
+    static_cast<void>(format);
+    const int lz = count_leading_zeros(w);
+    const std::uint64_t normalized = w << static_cast<unsigned>(lz);
+    const auto index = static_cast<std::size_t>(2 * (q - pow5_128_smallest_power));
+    const uint128_parts product = full_multiplication(normalized, pow5_128()[index]);
+    std::uint64_t high = product.high;
+    if (NLOHMANN_VIEW_UNLIKELY((high & 0x1FFu) == 0x1FFu))
+    {
+        // (the lower bits may carry into the result)
+        const std::uint64_t second = full_multiplication(normalized, pow5_128()[index + 1]).high;
+        high += product.low + second < product.low ? 1u : 0u;
+    }
+    const auto upperbit = static_cast<unsigned>(high >> 63u);
+    std::uint64_t mantissa = high >> (upperbit + 9);
+    auto power2 = static_cast<std::uint64_t>(((217706 * q) >> 16) + 63 + static_cast<std::int64_t>(upperbit) - lz + 1023);
+    mantissa = (mantissa + (mantissa & 1u)) >> 1u;
+    const bool carry = mantissa >= (std::uint64_t{2} << 52u);
+    mantissa = carry ? (std::uint64_t{1} << 52u) : mantissa;
+    power2 += carry ? 1u : 0u;
+    return (mantissa & ~(std::uint64_t{1} << 52u)) | (power2 << 52u);
+}
+
+/*!
+@brief (binary32 and binary64) the value of a float token of the source with
+16 or 17 digits, a point, and no exponent, the shape of most coordinates
+written with full precision; whether the token of n has this shape
+
+These tokens skip the general layout of layout_decimal(): no digits beyond
+the 17th, no exponent (and Eisel-Lemire directly, as in layout_float()).
+*/
+template<typename FloatType>
+NLOHMANN_VIEW_ALWAYS_INLINE bool coordinate_float(const document_data& d, const node& n, FloatType& value) noexcept
+{
+    const unsigned int_digits = n.extra & 0xFFu;
+    const unsigned frac_digits = n.extra >> 8u;
+    const unsigned count = int_digits + frac_digits;
+    const auto* const first = reinterpret_cast<const unsigned char*>(d.src + n.off); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+    const unsigned negative = first[0] == '-' ? 1u : 0u;
+    if (count - 16u > 1u || frac_digits == 0 || n.len != negative + count + 1 || d.size - n.off < 33)
+    {
+        return false;
+    }
+    const unsigned char* const digits = first + negative;
+    const std::uint64_t w = sixteen_digits(digits, int_digits);
+    // (the 17th digit follows the point)
+    const std::uint64_t w17 = (w * 10) + static_cast<std::uint64_t>(digits[17] - '0');
+    using format = ieee_binary_format<std::numeric_limits<FloatType>::digits>;
+    native_float_t<FloatType> result{};
+    float_from_bits(coordinate_bits(-static_cast<std::int64_t>(frac_digits), count == 17 ? w17 : w, format{}) | (static_cast<std::uint64_t>(negative) << format::sign_bit()), result);
+    value = result;
+    return true;
+}
+
+#endif
+
 /// the value of the float token of a node, as parse() converts it; floats and
 /// doubles with at most 19 digits are converted from the digit layout
 template<typename FloatType>
@@ -200,6 +348,13 @@ FloatType float_value(const document_data& d, const node& n)
 template<typename FloatType>
 FloatType float_value(const document_data& d, const node& n, std::true_type /*binary32 or binary64*/)
 {
+#if NLOHMANN_VIEW_VECTOR
+    FloatType value {};
+    if (coordinate_float(d, n, value))
+    {
+        return value;
+    }
+#endif
    const unsigned int_digits = n.extra & 0xFFu;
    const unsigned frac_digits = n.extra >> 8u;
    if (NLOHMANN_VIEW_LIKELY(int_digits + frac_digits <= 19)) // (255 marks "many")
@@ -14,7 +14,9 @@
 #include <cstddef> // size_t
 #include <cstdint> // uint8_t, uint32_t
 #include <cstring> // memcpy, memset
+#include <functional> // less
 #include <limits> // numeric_limits
+#include <memory> // unique_ptr
 #include <type_traits> // integral_constant
 #include <vector> // vector

@@ -384,6 +386,127 @@ struct depth_counter<false>
    }
 };

+/*!
+@brief where the double x nearest to a token w * 10^q lies, for 10^15 <= w <
+10^17 and -17 <= q <= -1 (Eisel-Lemire, then a fixed-point position)
+
+dump() writes the shortest decimal in the rounding interval of x (the closest
+one if there are several, see zmij::to_shortest()). Its digits are those of a
+multiple of 10^g of the token's last digit, with g = dec_exp + 1 - q for x's
+decimal exponent dec_exp: the multiple of 10^g nearest to x if it lies in the
+interval (at most one does), else the multiple of 10^(g - 1) nearest to x
+(see token_digits_1() and token_digits_2()). For g <= 0, the token itself is
+in the interval.
+
+The position is exact in a 64-bit fixed-point number with 56 bits after the
+point (of the token's last digit): x / 10^q = 2c * 5^-q / 2^t for x = c * 2^e2
+and t = q + 1 - e2, with at most 56 bits after the point here, and |x / 10^q -
+w| is at most half the spacing of the doubles, below 12 units. So only the low
+64 bits of 2c * 5^-q are needed. c and e2 come from Eisel-Lemire's product
+directly (as eisel_lemire() rounds it: no tie is possible for q < -4, and its
+second product is added where it can carry into the result).
+
+@param[out] offset  x / 10^q - w + 32, with 56 bits after the point
+@param[out] radius  half the spacing of the doubles at x, likewise (+ 1 if
+                    the interval is closed)
+@return g; 3 if the digits are not decided here (a power of two, whose
+        interval is not symmetric, or out of range)
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE int locate_token(std::uint64_t w, int q, std::uint64_t& offset, std::uint64_t& radius) noexcept
+{
+    const int lz = count_leading_zeros(w);
+    const std::uint64_t normalized = w << static_cast<unsigned>(lz);
+    const auto index = static_cast<std::size_t>(2 * (q - pow5_128_smallest_power));
+    const uint128_parts product = full_multiplication(normalized, pow5_128()[index]);
+    std::uint64_t high = product.high;
+    if (NLOHMANN_VIEW_UNLIKELY((high & 0x1FFu) == 0x1FFu))
+    {
+        // (as eisel_lemire(): the lower bits may carry into the result)
+        const std::uint64_t second = full_multiplication(normalized, pow5_128()[index + 1]).high;
+        high += product.low + second < product.low ? 1u : 0u;
+    }
+    const auto upperbit = static_cast<unsigned>(high >> 63u);
+    const std::uint64_t mantissa = high >> (upperbit + 9);
+    const std::uint64_t c = (mantissa + (mantissa & 1u)) >> 1u;
+    // e2 as eisel_lemire() computes the exponent (log2(10) ~ 217706 / 2^16)
+    const int e2 = static_cast<int>((217706 * static_cast<std::int64_t>(q)) >> 16) + 63 + static_cast<int>(upperbit) - lz - 52;
+    const int t = q + 1 - e2;
+    const int g = ((e2 * 315653) >> 20) + 1 - q; // (dec_exp as in zmij::to_shortest(), for a regular x)
+    static const std::array<std::uint64_t, 17> fives = {{1u, 5u, 25u, 125u, 625u, 3125u, 15625u, 78125u, 390625u, 1953125u, 9765625u, 48828125u, 244140625u, 1220703125u, 6103515625u, 30517578125u, 152587890625u}};
+    const std::uint64_t five = fives[static_cast<std::size_t>(-q)]; // 5^-q
+    const unsigned s = static_cast<unsigned>(56 - t) & 63u;
+    offset = ((2 * c * five) << s) - (w << 56u) + (std::uint64_t{32} << 56u);
+    radius = (five << s) + ((c & 1u) == 0 ? 1u : 0u);
+    // (c = 2^52: a power of two; c = 2^53: rounded up to one. With 8 to 16
+    // fraction digits, as the batch's tokens have, t is in [15, 40] and g at
+    // most 2. x lies halfway between two candidates only if its distance from
+    // the token is a whole unit (g == 2) or a half (g == 1): such tokens are
+    // left to the full conversion)
+    const bool decided = c - ((std::uint64_t{1} << 52u) + 1) < (std::uint64_t{1} << 52u) - 1
+                         && (offset & ((std::uint64_t{1} << 55u) - 1)) != 0;
+    return decided ? g : 3;
+}
+
+/// the distance of a position (see locate_token()) from the biased point 32
+NLOHMANN_VIEW_ALWAYS_INLINE std::uint64_t biased_distance(std::uint64_t position) noexcept
+{
+    constexpr std::uint64_t center = std::uint64_t{32} << 56u;
+    return position >= center ? position - center : center - position;
+}
+
+/*!
+@brief (g == 1) the digits dump() writes for a token, from the position of its
+double (see locate_token()): the multiple of 10 nearest to x if it is in the
+interval, else w rounded to x (an exact tie between two candidates, like
+754570942.33984373, whose double is 754570942.33984375, is excluded by
+locate_token())
+
+With |x - w| at most the radius, which is below half the spacing of the
+candidates, the multiple of 10 nearest to x is w - r10 or the one above it.
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE std::uint64_t token_digits_1(std::uint64_t w, std::uint64_t offset, std::uint64_t radius, std::uint64_t r10) noexcept
+{
+    constexpr std::uint64_t one = std::uint64_t{1} << 56u;
+    const std::uint64_t from = offset + (r10 * one); // x - (w - r10) (+ 32)
+    const bool up = from > 37 * one;                  // (nearer to the multiple above)
+    const bool shorter = biased_distance(from - (up ? 10 * one : 0)) < radius;
+    const std::uint64_t a = w - r10 + (up ? 10u : 0u);
+    const std::uint64_t b = w + ((offset + (one / 2)) >> 56u) - 32;                // w rounded to x
+    return shorter ? a : b;
+}
+
+/*!
+@brief (g == 2) the digits dump() writes for a token, as token_digits_1(): the
+multiple of 100 nearest to x if it is in the interval, else the multiple of 10
+nearest to x
+*/
+NLOHMANN_VIEW_ALWAYS_INLINE std::uint64_t token_digits_2(std::uint64_t w, std::uint64_t offset, std::uint64_t radius, std::uint64_t r10, std::uint64_t r100) noexcept
+{
+    constexpr std::uint64_t one = std::uint64_t{1} << 56u;
+    const std::uint64_t from = offset + (r100 * one);
+    const bool up = from > 82 * one;
+    const bool shorter = biased_distance(from - (up ? 100 * one : 0)) < radius;
+    const std::uint64_t a = w - r100 + (up ? 100u : 0u);
+    // x - (w - r10), in [-12, 21]: the multiple of 10 nearest to x is that one,
+    // or one or two above, or one below
+    const std::uint64_t y = offset + (r10 * one);
+    const std::uint64_t steps = (y > 37 * one ? 1u : 0u) + (y > 47 * one ? 1u : 0u);
+    const bool down = y < 27 * one;
+    const std::uint64_t b = w - r10 + (10 * steps) - (down ? 10u : 0u);
+    return shorter ? a : b;
+}
+
+/// the four ASCII digits of x < 10^4, the first in the lowest byte (as
+/// little-endian memory holds them)
+NLOHMANN_VIEW_ALWAYS_INLINE std::uint32_t four_digit_text(std::uint32_t x) noexcept
+{
+    const std::uint32_t ab = (x * 5243u) >> 19u; // x / 100
+    std::uint32_t v = ab | ((x - (ab * 100u)) << 16u);
+    const std::uint32_t a = ((v * 103u) >> 10u) & 0x000F000Fu; // / 10 per 16-bit lane
+    v = a | ((v - (a * 10u)) << 8u);
+    return v + 0x30303030u;
+}
+
 /// how the view's dump() writes a value
 struct dump_style
 {
@@ -711,6 +834,7 @@ class view_serializer
        std::array<frame, 32> buffer; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
        std::vector<frame> heap;
        small_stack<frame> stack(buffer.data(), buffer.size(), heap);
+        float_batch batch;
        const char* const src = m_doc.src;
        const char* const src_end = src + m_doc.size;
        char* w = m_out.cursor();
@@ -850,7 +974,7 @@ class view_serializer
                    else if (enabled(fast_double::value))
                    {
                        room(64);
-                        w = write_double_at(w, *n);
+                        w = write_double_ahead(w, src, n, batch);
                    }
                    else
                    {
@@ -875,6 +999,20 @@ class view_serializer
                case value_t::array:
                {
                    const bool object = n->kind == node_kind::object;
+                    // (read-only documents, compact output) a pair of floats,
+                    // like the coordinates of GeoJSON, without a frame
+                    if (enabled(!Editable && !Pretty && !SourceNumbers && fast_double::value) && n->next == 3 && n->len == 2
+                            && n[1].kind == node_kind::number_float && n[2].kind == node_kind::number_float)
+                    {
+                        room(2 * 64);
+                        *w++ = '[';
+                        w = write_double_ahead(w, src, n + 1, batch);
+                        *w++ = ',';
+                        w = write_double_ahead(w, src, n + 2, batch);
+                        *w++ = ']';
+                        n += 2; // (the element before the next node)
+                        break;
+                    }
                    room(8);
                    if (n->len == 0)
                    {
@@ -984,6 +1122,254 @@ class view_serializer
        }
    }

+    /// (float_batch) the mark of digits whose rounding carried beyond the
+    /// token's last four (see mark())
+    static constexpr std::uint64_t carried() noexcept
+    {
+        return std::uint64_t{1} << 63u;
+    }
+
+    /// floats of 16 or 17 digits ahead of the walk, converted together (see
+    /// convert_ahead()), with their digits as mark() keeps them
+    struct float_batch
+    {
+        static constexpr std::size_t capacity() noexcept
+        {
+            return 256;
+        }
+        /// (on the heap, allocated by the first conversion: a frame of more
+        /// than a page made every dump of a small document slower)
+        struct entries
+        {
+            std::array<const node*, 256> at; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+            std::array<std::uint64_t, 256> digits; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+        };
+        std::unique_ptr<entries> storage{};
+        const node** at = nullptr;
+        std::uint64_t* digits = nullptr;
+        std::size_t count = 0;
+        std::size_t next = 0;
+        const node* scanned = nullptr; ///< where the last scan of the node array ended
+    };
+
+    /// (doubles) the float at n as dump() writes it, at w (64 bytes of room):
+    /// from the batch if it holds n
+    NLOHMANN_VIEW_ALWAYS_INLINE char* write_double_ahead(char* w, const char* src, const node* n, float_batch& batch)
+    {
+#if NLOHMANN_VIEW_VECTOR && NLOHMANN_VIEW_LITTLE_ENDIAN
+        // (digits 0: not written by the batch; carried(): rounding carried
+        // beyond the last four digits)
+        if (batch.next != batch.count && batch.at[batch.next] == n && batch.digits[batch.next] - 1 < carried() - 1)
+        {
+            return write_token_digits(w, src, *n, batch.digits[batch.next++]);
+        }
+        return write_double_beside(w, n, batch);
+#else
+        static_cast<void>(src);
+        static_cast<void>(batch);
+        return write_double_at(w, *n);
+#endif
+    }
+
+#if NLOHMANN_VIEW_VECTOR && NLOHMANN_VIEW_LITTLE_ENDIAN
+    /// write_double_ahead() for a float that is not the batch's next one (out
+    /// of line: the walk is faster with less code in its loop)
+    NLOHMANN_VIEW_NOINLINE char* write_double_beside(char* w, const node* n, float_batch& batch)
+    {
+        // (an editable document's walk can skip nodes of the array)
+        const std::less<const node*> before{}; // NOLINT(modernize-use-transparent-functors) C++11 has no std::less<>
+        while (batch.next != batch.count && before(batch.at[batch.next], n))
+        {
+            ++batch.next;
+        }
+        if ((batch.next != batch.count && batch.at[batch.next] == n) || convert_ahead(n, batch))
+        {
+            const std::uint64_t digits = batch.digits[batch.next++];
+            if ((digits & carried()) != 0)
+            {
+                return write_carried_digits(w, *n, digits & ~carried());
+            }
+            if (digits != 0)
+            {
+                return write_token_digits(w, m_doc.src, *n, digits);
+            }
+        }
+        return write_double_at(w, *n);
+    }
+
+    /*!
+    @brief convert the floats of 16 or 17 digits among the next nodes of the
+    array at once; whether n is the first of them
+
+    Such tokens (like the coordinates of GeoJSON, written with 17 digits) are
+    written as the token with its last four digits replaced
+    (write_token_digits()). Each step (the digits, locate_token(),
+    token_digits_1/2()) is a long chain of dependent operations; one loop per
+    step over many floats lets the processor overlap the floats, which it does
+    not across the steps of one float (on Apple M1, one loop for the digits and
+    locate_token() made the dump of canada.json 12 % slower). Each node of the array
+    is scanned once; a node that the walk does not reach in order (in an
+    editable document) is written without the batch.
+    */
+    NLOHMANN_VIEW_NOINLINE bool convert_ahead(const node* n, float_batch& batch)
+    {
+        const std::less<const node*> before{}; // NOLINT(modernize-use-transparent-functors) C++11 has no std::less<>
+        const node* const last = m_doc.nodes + m_doc.node_count;
+        if (before(n, batch.scanned) || before(n, m_doc.nodes) || !before(n, last))
+        {
+            return false;
+        }
+        const char* const src = m_doc.src;
+        const char* const src_end = src + m_doc.size;
+        const node* const stop = last - n > 1024 ? n + 1024 : last;
+        batch.count = 0;
+        batch.next = 0;
+        // the digits of each token (and its last four from the text)
+        std::array<std::uint64_t, 256> digits;     // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+        std::array<int, 256> exponent;             // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+        std::array<std::uint32_t, 256> last_four;  // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+        const node* p = n;
+        if (!batch.storage)
+        {
+            batch.storage.reset(new typename float_batch::entries); // NOLINT(cppcoreguidelines-owning-memory,modernize-make-unique): C++11
+            batch.at = batch.storage->at.data();
+            batch.digits = batch.storage->digits.data();
+        }
+        for (; p != stop && batch.count != float_batch::capacity(); ++p)
+        {
+            // a token of the source: 16 or 17 digits, at least 8 after the
+            // point, no exponent, 32 bytes to read
+            const unsigned frac_digits = p->extra >> 8u;
+            const unsigned int_digits = p->extra & 0xFFu;
+            const unsigned count = int_digits + frac_digits;
+            if (p->kind == node_kind::number_float && (p->flags & node_flags::storage) == 0
+                    && count - 16u <= 1u && frac_digits >= 8 && src_end - (src + p->off) >= 33)
+            {
+                const auto* const token = reinterpret_cast<const unsigned char*>(src + p->off); // NOLINT(cppcoreguidelines-pro-type-reinterpret-cast)
+                const unsigned sign = token[0] == '-' ? 1 : 0;
+                const unsigned char* const first = token + sign;
+                const std::uint64_t w = sixteen_digits(first, int_digits);
+                // (the 17th digit follows the point; a token with an exponent
+                // gets digits outside the range of locate_token(), and is not
+                // written by the batch. A token 0.xxx with 16 significant
+                // digits is: its double is written as "0." and its digits too)
+                const std::uint64_t w17 = (w * 10) + static_cast<std::uint64_t>(first[17] - '0');
+                const std::size_t i = batch.count++;
+                batch.at[i] = p;
+                if (p->len != sign + count + 1)
+                {
+                    digits[i] = 0;
+                }
+                else
+                {
+                    digits[i] = count == 17 ? w17 : w;
+                }
+                exponent[i] = -static_cast<int>(frac_digits);
+                // (byte 0: the last digit, byte 1: the last two, bits 16-29: the last four)
+                std::uint32_t four = 0;
+                std::memcpy(&four, token + p->len - 4, 4);
+                four -= 0x30303030u;
+                const std::uint32_t pairs = ((four & 0x0F0F0F0Fu) * 2561u) >> 8u; // (byte 0, 2: the pairs)
+                last_four[i] = (four >> 24u) | ((pairs >> 16u & 0xFFu) << 8u) | ((((pairs & 0x00FF00FFu) * 6553601u) >> 16u) << 16u);
+            }
+        }
+        batch.scanned = p;
+        // the position of each double, and the floats of either kind
+        std::array<std::uint64_t, 256> offset; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+        std::array<std::uint64_t, 256> radius; // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+        std::array<std::uint8_t, 256> kind_1;  // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+        std::array<std::uint8_t, 256> kind_2;  // NOLINT(cppcoreguidelines-pro-type-member-init,hicpp-member-init): written before read
+        std::size_t count_1 = 0;
+        std::size_t count_2 = 0;
+        for (std::size_t i = 0; i != batch.count; ++i)
+        {
+            const std::uint64_t w = digits[i];
+            // (the range excludes the values of bytes that are not digits, only
+            // in a damaged image loaded with image_check::bounds)
+            const int g = w - 1000000000000000u < 99000000000000000u ? locate_token(w, exponent[i], offset[i], radius[i]) : 3;
+            batch.digits[i] = g <= 0 ? (last_four[i] >> 16u) + 1 : 0;
+            kind_1[count_1] = static_cast<std::uint8_t>(i);
+            count_1 += g == 1 ? 1 : 0;
+            kind_2[count_2] = static_cast<std::uint8_t>(i);
+            count_2 += g == 2 ? 1 : 0;
+        }
+        // the digits to write, in one loop per kind (see mark())
+        for (std::size_t k = 0; k != count_1; ++k)
+        {
+            const std::size_t i = kind_1[k];
+            const std::uint64_t s = token_digits_1(digits[i], offset[i], radius[i], last_four[i] & 0xFFu);
+            batch.digits[i] = mark(digits[i], s, last_four[i] >> 16u);
+        }
+        for (std::size_t k = 0; k != count_2; ++k)
+        {
+            const std::size_t i = kind_2[k];
+            const std::uint64_t s = token_digits_2(digits[i], offset[i], radius[i], last_four[i] & 0xFFu, (last_four[i] >> 8u) & 0xFFu);
+            batch.digits[i] = mark(digits[i], s, last_four[i] >> 16u);
+        }
+        return batch.count != 0 && batch.at[0] == n;
+    }
+
+    /*!
+    @brief a float token of 16 or 17 digits as dump() writes it, at w (64 bytes
+    of room), from the digits of its double (see locate_token()) whose
+    rounding carried beyond the token's last four digits
+
+    (like 43.42027299999999 -> 43.420273): the digits go to the writer of
+    Zmij's results as its 15 or 16 leading digits and one more, which omits
+    the trailing zeros.
+    */
+    NLOHMANN_VIEW_NOINLINE char* write_carried_digits(char* w, const node& n, std::uint64_t digits) const noexcept
+    {
+        const int exponent = -(n.extra >> 8u);
+        const std::uint64_t leading = digits / 10;
+        const auto last = static_cast<unsigned char>(digits - (leading * 10));
+        const bool seventeen = digits >= 10000000000000000u;
+        *w = '-';
+        w += m_doc.src[n.off] == '-' ? 1 : 0;
+        return ::nlohmann::detail::dtoa_impl::write_shortest(w, seventeen ? ::nlohmann::detail::zmij::shortest_decimal{leading, exponent, last, last != 0}
+                : ::nlohmann::detail::zmij::shortest_decimal{digits, exponent - 1, 0, false});
+    }
+
+    /// the digits s of a token with the digits w and the last four digits
+    /// r4, as the batch keeps them: the new last four digits + 1 (only those
+    /// are written over the token's), or s marked if it differs from w beyond
+    /// them (0 stays for a float the batch does not write)
+    static std::uint64_t mark(std::uint64_t w, std::uint64_t s, std::uint64_t r4) noexcept
+    {
+        const std::uint64_t last = s - (w - r4);
+        return last < 10000 ? last + 1 : s | carried();
+    }
+
+    /*!
+    @brief a float token of 16 or 17 digits as dump() writes it, at w (64 bytes
+    of room): the token with its last four digits replaced by digits - 1 (see
+    mark(); the others are the token's), and without trailing zeros after the
+    point, but one
+    */
+    char* write_token_digits(char* w, const char* src, const node& n, std::uint64_t digits)
+    {
+        const char* const token = src + n.off;
+        std::memcpy(w, token, 32);
+        char* const end = w + n.len;
+        const std::uint32_t last = four_digit_text(static_cast<std::uint32_t>(digits - 1));
+        std::memcpy(end - 4, &last, 4);
+        // (the token's text before the new digits, from the source: reading
+        // the output back would wait for the stores)
+        std::uint64_t before = 0;
+        std::memcpy(&before, token + n.len - 12, 8);
+        const std::uint32_t last_zeros = last ^ 0x30303030u;
+        const std::uint64_t before_zeros = before ^ 0x3030303030303030u;
+        if (NLOHMANN_VIEW_UNLIKELY(last_zeros == 0 && before_zeros == 0))
+        {
+            return write_double_at(w, n); // (twelve or more trailing zeros)
+        }
+        const unsigned zeros = last_zeros != 0 ? (static_cast<unsigned>(count_leading_zeros(last_zeros)) / 8) - 4
+                               : 4 + (static_cast<unsigned>(count_leading_zeros(before_zeros)) / 8);
+        const unsigned frac_digits = n.extra >> 8u;
+        return end - (zeros < frac_digits ? zeros : frac_digits - 1);
+    }
+#endif
+
    /// a float node as dump() writes it
    void write_float_node(const node& n)
    {
@@ -159,7 +159,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    friend class ::nlohmann::detail::binary_writer;
    template<typename BasicJsonType, typename InputType, typename SAX>
    friend class ::nlohmann::detail::binary_reader;
-    template<typename BasicJsonType, typename InputAdapterType, bool Collect, typename LexerType>
+    template<typename BasicJsonType, typename InputAdapterType, bool Collect>
    friend class ::nlohmann::detail::json_sax_dom_parser;
    template<typename BasicJsonType, typename InputAdapterType>
    friend class ::nlohmann::detail::json_sax_dom_binary_parser;
@@ -15629,10 +15629,7 @@ struct diagnostic_positions
        {
            // Lexer has read the first character of the container, so
            // subtract 1 from the position to get the correct start position.
-            // (npos: a value without a source position, see materialize() of
-            // json_view)
-            const std::size_t read = lexer->get_chars_read_total();
-            v.start_position = read == std::string::npos ? read : read - 1;
+            v.start_position = lexer->get_chars_read_total() - 1;
        }
    }

@@ -15647,12 +15644,6 @@ struct diagnostic_positions
        {
            // Lexer's position is past the closing brace or bracket, so set that as the end position.
            v.end_position = lexer->get_chars_read_total();
-            if (v.end_position == std::string::npos)
-            {
-                // a range has both ends or none (exception::diagnostics()
-                // prints only complete ones)
-                v.start_position = v.end_position;
-            }
        }
    }

@@ -15669,12 +15660,6 @@ struct diagnostic_positions
            // The start position will be set below based on the length of the string representation
            // of the value.
            v.end_position = lexer->get_chars_read_total();
-            if (v.end_position == std::string::npos)
-            {
-                // a value without a source position
-                v.start_position = v.end_position;
-                return;
-            }

            switch (v.type())
            {
@@ -15887,12 +15872,8 @@ read up to it.
@tparam Collect  whether to collect the values of containers of unknown size on
                 a stack (only for a caller that does not use the value after a
                 parse error)
-@tparam LexerType  the type of the lexer that reports the source positions
-                   (JSON_DIAGNOSTIC_POSITIONS); only diagnostic_positions uses
-                   it, so any type with its three functions works (as
-                   materialize() of json_view uses it)
 */
-template<typename BasicJsonType, typename InputAdapterType, bool Collect = false, typename LexerType = lexer<BasicJsonType, InputAdapterType>>
+template<typename BasicJsonType, typename InputAdapterType, bool Collect = false>
 class json_sax_dom_parser : public json_sax_dom_error_state
 {
  public:
@@ -15901,7 +15882,7 @@ class json_sax_dom_parser : public json_sax_dom_error_state
    using number_float_t = typename BasicJsonType::number_float_t;
    using string_t = typename BasicJsonType::string_t;
    using binary_t = typename BasicJsonType::binary_t;
-    using lexer_t = LexerType;
+    using lexer_t = lexer<BasicJsonType, InputAdapterType>;

    /*!
    @param[in,out] r  reference to a JSON value that is manipulated while
@@ -22534,8 +22515,8 @@ using parser_callback_t =
 template<typename SAX>
 struct sax_ignores_number_text : std::false_type {};

-template<typename BasicJsonType, typename InputAdapterType, bool Collect, typename LexerType>
-struct sax_ignores_number_text<json_sax_dom_parser<BasicJsonType, InputAdapterType, Collect, LexerType>> : std::true_type {};
+template<typename BasicJsonType, typename InputAdapterType, bool Collect>
+struct sax_ignores_number_text<json_sax_dom_parser<BasicJsonType, InputAdapterType, Collect>> : std::true_type {};

 template<typename BasicJsonType, typename InputAdapterType>
 struct sax_ignores_number_text<json_sax_dom_callback_parser<BasicJsonType, InputAdapterType>> : std::true_type {};
@@ -36473,7 +36454,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
    friend class ::nlohmann::detail::binary_writer;
    template<typename BasicJsonType, typename InputType, typename SAX>
    friend class ::nlohmann::detail::binary_reader;
-    template<typename BasicJsonType, typename InputAdapterType, bool Collect, typename LexerType>
+    template<typename BasicJsonType, typename InputAdapterType, bool Collect>
    friend class ::nlohmann::detail::json_sax_dom_parser;
    template<typename BasicJsonType, typename InputAdapterType>
    friend class ::nlohmann::detail::json_sax_dom_binary_parser;
@@ -749,20 +749,6 @@ std::string exception_of(F f)
    }
    return "";
 }
-
-// the exception a call on a basic_json value throws, without the byte range of
-// the value (JSON_DIAGNOSTIC_POSITIONS), which the exceptions of views lack
-template<typename F>
-std::string json_exception_of(F f)
-{
-    std::string what = exception_of(f);
-    const std::size_t at = what.find("] (bytes ");
-    if (at != std::string::npos)
-    {
-        what.erase(at + 2, what.find(") ", at) - at);
-    }
-    return what;
-}
 #endif

 // compares a view with the ordered_json value materialize() gives for it:
@@ -971,24 +957,24 @@ TEST_CASE("json_view element access and iteration")
 #if !defined(JSON_NOEXCEPTION)
            if (!j.is_object())
            {
-                CHECK(exception_of([&] { static_cast<void>(v["a"]); }) == json_exception_of([&] { static_cast<void>(j["a"]); }));
+                CHECK(exception_of([&] { static_cast<void>(v["a"]); }) == exception_of([&] { static_cast<void>(j["a"]); }));
            }
            if (!j.is_array())
            {
-                CHECK(exception_of([&] { static_cast<void>(v[0]); }) == json_exception_of([&] { static_cast<void>(j[0]); }));
+                CHECK(exception_of([&] { static_cast<void>(v[0]); }) == exception_of([&] { static_cast<void>(j[0]); }));
            }
-            CHECK(exception_of([&] { static_cast<void>(v.at("a")); }) == json_exception_of([&] { static_cast<void>(j.at("a")); }));
-            CHECK(exception_of([&] { static_cast<void>(v.at("missing")); }) == json_exception_of([&] { static_cast<void>(j.at("missing")); }));
-            CHECK(exception_of([&] { static_cast<void>(v.at(0)); }) == json_exception_of([&] { static_cast<void>(j.at(0)); }));
-            CHECK(exception_of([&] { static_cast<void>(v.at(5)); }) == json_exception_of([&] { static_cast<void>(j.at(5)); }));
+            CHECK(exception_of([&] { static_cast<void>(v.at("a")); }) == exception_of([&] { static_cast<void>(j.at("a")); }));
+            CHECK(exception_of([&] { static_cast<void>(v.at("missing")); }) == exception_of([&] { static_cast<void>(j.at("missing")); }));
+            CHECK(exception_of([&] { static_cast<void>(v.at(0)); }) == exception_of([&] { static_cast<void>(j.at(0)); }));
+            CHECK(exception_of([&] { static_cast<void>(v.at(5)); }) == exception_of([&] { static_cast<void>(j.at(5)); }));
            if (!(j.is_object() && j.empty())) // (key() of an end iterator)
            {
-                CHECK(exception_of([&] { static_cast<void>(v.begin().key()); }) == json_exception_of([&] { static_cast<void>(j.begin().key()); }));
+                CHECK(exception_of([&] { static_cast<void>(v.begin().key()); }) == exception_of([&] { static_cast<void>(j.begin().key()); }));
            }
            if (!j.empty() || j.is_null())
            {
-                CHECK(exception_of([&] { static_cast<void>(v.front()); }) == json_exception_of([&] { static_cast<void>(j.front()); }));
-                CHECK(exception_of([&] { static_cast<void>(v.back()); }) == json_exception_of([&] { static_cast<void>(j.back()); }));
+                CHECK(exception_of([&] { static_cast<void>(v.front()); }) == exception_of([&] { static_cast<void>(j.front()); }));
+                CHECK(exception_of([&] { static_cast<void>(v.back()); }) == exception_of([&] { static_cast<void>(j.back()); }));
            }
 #endif
            CHECK(v.contains("a") == j.contains("a"));
@@ -35,9 +35,9 @@ using json_view_test::has_duplicate_keys;
 #include <string>
 #include <vector>

-// These tests were split off unit-json_view.cpp, whose object file got too large
-// for the MinGW linker (see json_view_test_helpers.hpp). Like that file, this one
-// is also built with C++17, as it mentions JSON_HAS_CPP_17.
+// These tests were split off unit-json_view.cpp, whose object file got too large for the MinGW
+// linker (see json_view_test_helpers.hpp). Like that file, this one is also built
+// with C++17, as it mentions JSON_HAS_CPP_17.

 TEST_CASE("json_view dump")
 {
@@ -150,6 +150,88 @@ TEST_CASE("json_view dump")
            CHECK(many_doc.root().dump() == json::parse(many_tokens).dump());
        }

+        // tokens of 16 and 17 digits without an exponent (like GeoJSON
+        // coordinates), which dump() converts in batches: doubles exactly
+        // halfway between two candidates for the shortest digits, random
+        // digits, and digits near a shorter decimal (...99999997,
+        // ...00000003), whose rounding carries; in pairs and among other
+        // values, so that the batches are interrupted; the last token near the
+        // end of the text
+        {
+            std::mt19937_64 tokens(5627); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
+            const auto draw = [&tokens](std::size_t n)
+            {
+                const std::uint64_t r = tokens() % n;
+                return static_cast<std::size_t>(r);
+            };
+            std::string coordinates = "[754570942.33984373,257769445.56835938,858106901.94921875,97944964.876953125,"
+                                      "[0.5,1e-7],[1.5,-0.0,2.5],[1E2,12.5,0.1,3.25,4.5,5.75,6.125,7.0,8.5],[],[1.5],[1,2.5],[2.5,\"x\"],[[1.5],2.5],";
+            for (int i = 0; i < 20000; ++i)
+            {
+                const std::size_t length = 16 + draw(2);
+                std::string digits(1, static_cast<char>('1' + draw(9)));
+                const std::size_t kept = draw(3) == 0 ? length : 2 + draw(length - 3);
+                for (std::size_t k = 1; k < kept; ++k)
+                {
+                    digits += static_cast<char>('0' + draw(10));
+                }
+                digits += std::string(length - kept, draw(2) == 0 ? '9' : '0');
+                digits.back() = static_cast<char>('0' + draw(10));
+                const std::size_t point = 1 + draw(9);
+                const std::string token = (draw(2) == 0 ? "-" : "") + digits.substr(0, point) + "." + digits.substr(point);
+                if (i != 0)
+                {
+                    coordinates += ',';
+                }
+                if (draw(8) == 0)
+                {
+                    coordinates += R"({"x":)";
+                    coordinates += token;
+                    coordinates += R"(,"s":"a"})";
+                }
+                else
+                {
+                    coordinates += '[';
+                    coordinates += token;
+                    coordinates += ',';
+                    coordinates += token;
+                    coordinates += ']';
+                }
+            }
+            coordinates += ",-65.613616999999977]";
+            const json_document parsed = json_document::parse(coordinates);
+            const ordered_json j = ordered_json::parse(coordinates);
+            CHECK(parsed.root().dump() == j.dump());
+            CHECK(parsed.root().dump(1) == j.dump(1));
+            CHECK(parsed.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
+            CHECK(parsed.root().back().get<double>() == j.back().get<double>());
+            CHECK(parsed.root().back().dump() == "-65.61361699999998");
+            std::size_t i = 0;
+            for (const json_view v : parsed.root())
+            {
+                const ordered_json& e = j[i++];
+                CHECK(v.dump() == e.dump());
+                if (v.is_array() && !v.empty() && v[0].is_number())
+                {
+                    CHECK(v[0].get<double>() == e[0].get<double>());
+                }
+            }
+
+            // an editable document: edits move some arrays, so that the walk
+            // leaves the order of the parsed nodes
+            ordered_json_editable_document editable = ordered_json_editable_document::parse(coordinates);
+            ordered_json expected = j;
+            for (std::size_t k = 0; k < 20000; k += 97)
+            {
+                if (expected[k].is_array())
+                {
+                    editable.push_back(editable.root()[k], ordered_json(1.5));
+                    expected[k].push_back(1.5);
+                }
+            }
+            CHECK(editable.root().dump() == expected.dump());
+        }
+
        // random doubles, written as parse() and dump() would
        std::mt19937_64 rng(1170); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
        std::string many = "[";
@@ -171,768 +253,4 @@ TEST_CASE("json_view dump")
        const nlohmann::basic_json_document<json_float> float_document = nlohmann::basic_json_document<json_float>::parse("[0.1, 1.5e10, 3.4028235e38]");
        CHECK(float_document.root().dump() == json_float::parse("[0.1, 1.5e10, 3.4028235e38]").dump());
    }
-
-    SECTION("members in document order, all of them")
-    {
-        const json_document d = json_document::parse(R"({"b": 1, "a": 2, "b": 3})");
-        CHECK(d.root().dump() == R"({"b":1,"a":2,"b":3})");
-        CHECK(d.root().dump(1) == "{\n \"b\": 1,\n \"a\": 2,\n \"b\": 3\n}");
-        // dump() writes all members, though the lookup finds the first
-        CHECK(d.root()["b"].dump() == "1");
-    }
-
-    SECTION("deep nesting")
-    {
-        const std::string deep = std::string(100000, '[') + std::string(100000, ']');
-        const json_document deep_document = json_document::parse(deep);
-        CHECK(deep_document.root().dump() == deep);
-    }
-
-    SECTION("ensure_ascii: a character that needs an escape at each position of a string")
-    {
-        // string lengths around the width of the vector steps, in a string value, a key, and a value near the end of the text
-        for (const char* const special :
-                {
-                    "\xC3\xA9", "\xE4\xB8\xAD", "\xF0\x9F\x98\x80", "\x7F", "\\n", "\\u0001", "\\\"", "\\\\"
-                })
-        {
-            for (std::size_t length = 0; length <= 40; ++length)
-            {
-                for (std::size_t position = 0; position <= length; ++position)
-                {
-                    std::string content(length, 'a');
-                    content.insert(position, special);
-                    const std::array<std::string, 3> texts =
-                    {
-                        {
-                            "\"" + content + "\"",
-                            "[\"" + content + "\"]",
-                            "{\"" + content + "\":1}",
-                        }
-                    };
-                    for (const std::string& text : texts)
-                    {
-                        CAPTURE(text)
-                        const ordered_json_document d = ordered_json_document::parse(text);
-                        const ordered_json j = ordered_json::parse(text);
-                        CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
-                        CHECK(d.root().dump(2, ' ', true) == j.dump(2, ' ', true));
-                        CHECK(d.root().dump() == j.dump());
-                    }
-                }
-            }
-        }
-    }
-
-    SECTION("ensure_ascii: every character of the Basic Multilingual Plane and some beyond")
-    {
-        // (the two- and three-byte sequences, including the ranges that need a check: E0, ED, EF BF BF)
-        std::string text = "[";
-        std::size_t in_chunk = 0;
-        const auto append = [&](std::uint32_t cp)
-        {
-            if (cp < 0x80)
-            {
-                if (cp < 0x20 || cp == '"' || cp == '\\')
-                {
-                    return;
-                }
-                text += static_cast<char>(cp);
-            }
-            else if (cp < 0x800)
-            {
-                text += static_cast<char>(0xC0 | (cp >> 6));
-                text += static_cast<char>(0x80 | (cp & 0x3F));
-            }
-            else if (cp < 0x10000)
-            {
-                text += static_cast<char>(0xE0 | (cp >> 12));
-                text += static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
-                text += static_cast<char>(0x80 | (cp & 0x3F));
-            }
-            else
-            {
-                text += static_cast<char>(0xF0 | (cp >> 18));
-                text += static_cast<char>(0x80 | ((cp >> 12) & 0x3F));
-                text += static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
-                text += static_cast<char>(0x80 | (cp & 0x3F));
-            }
-        };
-        for (std::uint32_t cp = 0x20; cp < 0x10400; ++cp)
-        {
-            if (cp >= 0xD800 && cp < 0xE000)
-            {
-                continue;
-            }
-            if (in_chunk == 0)
-            {
-                text += text.size() > 1 ? ",\"" : "\"";
-            }
-            append(cp);
-            if (++in_chunk == 37)
-            {
-                text += "\"";
-                in_chunk = 0;
-            }
-        }
-        text += in_chunk != 0 ? "\"]" : "]";
-        const ordered_json_document d = ordered_json_document::parse(text);
-        const ordered_json j = ordered_json::parse(text);
-        CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
-        CHECK(d.root().dump(2, ' ', true) == j.dump(2, ' ', true));
-        CHECK(d.root().dump() == j.dump());
-        CHECK(d.root().dump(2) == j.dump(2));
-    }
-
-    SECTION("deep nesting, indented")
-    {
-        // indentations of up to and beyond the width of the writer's fixed-size copy
-        for (const int depth :
-                {
-                    1, 5, 20, 70, 300
-                })
-        {
-            std::string text;
-            for (int i = 0; i < depth; ++i)
-            {
-                text += i % 2 == 0 ? "[1," : R"({"k":2,"\u00e9":)";
-            }
-            text += "[]";
-            for (int i = depth - 1; i >= 0; --i)
-            {
-                text += i % 2 == 0 ? "]" : "}";
-            }
-            const ordered_json_document d = ordered_json_document::parse(text);
-            const ordered_json j = ordered_json::parse(text);
-            for (const int indent :
-                    {
-                        0, 1, 2, 3, 8
-                    })
-            {
-                CHECK(d.root().dump(indent) == j.dump(indent));
-                CHECK(d.root().dump(indent, '\t') == j.dump(indent, '\t'));
-            }
-        }
-    }
-
-    SECTION("the output buffer of a small value is small")
-    {
-        // an escaped key after the value: its node lies in the arena, so the
-        // source extent of the value cannot be read from the next node
-        const std::string big(100000, 'a');
-        const std::string text = R"({"small":1,"list":[1,2,3],"k\n":")" + big + R"("})";
-        const json_document d = json_document::parse(text);
-        const auto small = d.root()["small"].dump();
-        CHECK(small == "1");
-        CHECK(small.capacity() < 4096);
-        const auto list = d.root()["list"].dump();
-        CHECK(list == "[1,2,3]");
-        CHECK(list.capacity() < 4096);
-        CHECK(d.root()["list"].dump(2).capacity() < 4096);
-
-        // the whole document and the large value are unaffected
-        CHECK(d.root().dump() == ordered_json::parse(text).dump());
-        CHECK(d.root()["k\n"].dump() == "\"" + big + "\"");
-    }
-
-    SECTION("output that outgrows the estimate")
-    {
-        // ensure_ascii writes six bytes for each two-byte character
-        std::string chars;
-        for (int i = 0; i < 5000; ++i)
-        {
-            chars += "\xC3\xA9";
-        }
-        const json_document d = json_document::parse(R"({"a":")" + chars + R"(","k\n":1})");
-        const json expected = json::parse("\"" + chars + "\"");
-        CHECK(d.root()["a"].dump(-1, ' ', true) == expected.dump(-1, ' ', true));
-        CHECK(d.root()["a"].dump(-1, ' ', true).size() == 2 + (5000 * 6));
-    }
-
-    SECTION("ensure_ascii with strings of the source, decoded strings, and edited strings")
-    {
-        // plain ASCII, non-ASCII, escaped (decoded), and mixed strings, as values and as keys;
-        // the second text has a DEL, which ensure_ascii writes as an escape
-        for (const char* const del :
-                {"", "\x7F"
-                })
-        {
-            const std::string text = std::string("{\"plain\":\"abc\",\"caf\xC3\xA9\":\"\xC3\xA9\xE2\x82\xAC\xF0\x9F\x98\x80\",")
-                                     + "\"esc\\n\\\"\":\"a\\tb\\u00e4\\ud83d\\ude00\",\"del\":\"a" + del + "b\",\"\":\"\"," // NOLINT(modernize-raw-string-literal)
-                                     + "\"list\":[\"x\",\"\xC3\xBC\",\"\\\\\",\"long ASCII string with more than thirty-two bytes in it\","
-                                     + "\"long string with more than thirty-two bytes and one non-ASCII byte \xC3\xB6\"],"
-                                     + "\"n\":[1,2.5,-0,true,null]}";
-            const ordered_json j = ordered_json::parse(text);
-            const ordered_json_document d = ordered_json_document::parse(text);
-            CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
-            CHECK(d.root().dump(4, ' ', true) == j.dump(4, ' ', true));
-            CHECK(d.root().dump() == j.dump());
-            CHECK(d.root()["list"].dump(-1, ' ', true) == j["list"].dump(-1, ' ', true));
-            CHECK(d.root()["del"].dump(-1, ' ', true) == j["del"].dump(-1, ' ', true));
-
-            // strings that an edit wrote (the source strings that they replace were plain)
-            ordered_json_editable_document e = ordered_json_editable_document::parse(text);
-            ordered_json k = j;
-            e.set(e.root()["plain"], std::string("\xC3\xA4gypten"));
-            k["plain"] = "\xC3\xA4gypten";
-            e.set(e.root()["list"][0], std::string("ascii after edit"));
-            k["list"][0] = "ascii after edit";
-            e.set(e.root()["list"][1], std::string("\xC3\xA4"));
-            k["list"][1] = "\xC3\xA4";
-            e.set(e.root()["del"], std::string("tab\there"));
-            k["del"] = "tab\there";
-            CHECK(e.root().dump(-1, ' ', true) == k.dump(-1, ' ', true));
-            CHECK(e.root().dump(2, ' ', true) == k.dump(2, ' ', true));
-            CHECK(e.root().dump() == k.dump());
-
-            // strings that were edited from or to ASCII text
-            e.set(e.root()["list"][2], std::string("\xC3\xA4"));
-            k["list"][2] = "\xC3\xA4";
-            e.set(e.root()["list"][4], std::string("plain again"));
-            k["list"][4] = "plain again";
-            CHECK(e.root().dump(-1, ' ', true) == k.dump(-1, ' ', true));
-        }
-    }
-
-    SECTION("ensure_ascii with DEL or a non-ASCII character at every position")
-    {
-        // the check whether a string of the source has no byte >= 0x7F reads
-        // eight bytes at a time and then the rest one by one
-        for (std::size_t length = 1; length <= 20; ++length)
-        {
-            for (std::size_t pos = 0; pos < length; ++pos)
-            {
-                for (const char* const c :
-                        {
-                            "\x7F", "\x7E", "\xC3\xA4", "\xC3\xBF" // NOLINT(modernize-raw-string-literal)
-                        })
-                {
-                    const std::string s = std::string(pos, 'a') + c + std::string(length - pos - 1, 'b');
-                    std::string text = "[\"";
-                    text.append(s).append("\",{\"").append(s).append("\":1}]");
-                    const json_document d = json_document::parse(text);
-                    const json j = json::parse(text);
-                    CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
-                    CHECK(d.root().dump(1, ' ', true) == j.dump(1, ' ', true));
-                }
-            }
-        }
-    }
-
-    SECTION("streams and discarded views")
-    {
-        const json_document d = json_document::parse(R"({"a": [1, 2]})");
-        std::ostringstream compact;
-        compact << d.root();
-        CHECK(compact.str() == R"({"a":[1,2]})");
-        std::ostringstream pretty;
-        pretty << std::setw(2) << std::setfill('.') << d.root() << d.root()["a"];
-        CHECK(pretty.str() == "{\n..\"a\": [\n....1,\n....2\n..]\n}[1,2]");
-        CHECK(json_view().dump() == json(json::value_t::discarded).dump());
-    }
-}
-
-TEST_CASE("json_view comparison")
-{
-    SECTION("equality of the values parse() produces")
-    {
-        generator g;
-        std::vector<std::string> texts;
-        for (int i = 0; i < 600; ++i)
-        {
-            std::string text;
-            g.value(text, 0);
-            texts.push_back(text);
-            // the same value written differently: sorted keys, canonical numbers
-            texts.push_back(json::parse(text).dump(1));
-        }
-        for (std::size_t i = 0; i + 2 < texts.size(); ++i)
-        {
-            for (std::size_t k = i; k < i + 3; ++k)
-            {
-                CAPTURE(texts[i])
-                CAPTURE(texts[k])
-                const json_document a = json_document::parse(texts[i]);
-                const json_document b = json_document::parse(texts[k]);
-                const json ja = json::parse(texts[i]);
-                const json jb = json::parse(texts[k]);
-                CHECK((a.root() == b.root()) == (ja == jb));
-                CHECK((a.root() != b.root()) == (ja != jb));
-                CHECK((a.root() == jb) == (ja == jb));
-                CHECK((jb == a.root()) == (ja == jb));
-                CHECK((a.root() != jb) == (ja != jb));
-                CHECK((jb != a.root()) == (ja != jb));
-
-                // ordered_json compares members in order
-                const ordered_json_document oa = ordered_json_document::parse(texts[i]);
-                const ordered_json_document ob = ordered_json_document::parse(texts[k]);
-                const ordered_json oja = ordered_json::parse(texts[i]);
-                const ordered_json ojb = ordered_json::parse(texts[k]);
-                CHECK((oa.root() == ob.root()) == (oja == ojb));
-                CHECK((oa.root() == ojb) == (oja == ojb));
-            }
-        }
-    }
-
-    SECTION("numbers, duplicate keys, member order")
-    {
-        const auto same = [](const char* x, const char* y)
-        {
-            const json_document dx = json_document::parse(x);
-            const json_document dy = json_document::parse(y);
-            return dx.root() == dy.root();
-        };
-        CHECK(same("1", "1.0"));
-        CHECK(same("[1, -1, 2.5]", "[1.0, -1.0, 25e-1]"));
-        CHECK(!same("1", "1.5"));
-        CHECK(same("18446744073709551615", "18446744073709551615"));
-        CHECK(same(R"({"a": 1, "a": 2})", R"({"a": 2})"));
-        CHECK(!same(R"({"a": 1, "a": 2})", R"({"a": 1})"));
-        CHECK(same(R"({"a": 1, "b": 2})", R"({"b": 2, "a": 1})"));
-        CHECK(!same(R"({"a": 1})", R"({"a": 1, "b": 2})"));
-        CHECK(!same("[1, 2]", "[2, 1]"));
-        CHECK(!same("\"a\"", "\"b\""));
-        CHECK(same("\"\\u00e9\"", "\"\xc3\xa9\""));
-        CHECK(!same("null", "false"));
-        CHECK(!same("[]", "{}"));
-        const ordered_json_document dup = ordered_json_document::parse(R"({"a": 1, "b": 2, "a": 3})");
-        const ordered_json_document last = ordered_json_document::parse(R"({"a": 3, "b": 2})");
-        CHECK(dup.root() == last.root());
-        // (== compares as parse() resolves duplicates, a lookup finds the first)
-        CHECK(dup.root()["a"].materialize() == 1);
-        CHECK(dup.root()["a"] != last.root()["a"]);
-        const ordered_json_document ab = ordered_json_document::parse(R"({"a": 1, "b": 2})");
-        const ordered_json_document ba = ordered_json_document::parse(R"({"b": 2, "a": 1})");
-        CHECK(ab.root() != ba.root());
-
-        // discarded values compare as basic_json's do
-        const json discarded(json::value_t::discarded);
-        CHECK((json_view() == json_view()) == (discarded == discarded)); // NOLINT(readability-container-size-empty): operator== is tested
-        CHECK((json_view() == discarded) == (discarded == discarded)); // NOLINT(readability-container-size-empty)
-        const json_document null_document = json_document::parse("null");
-        CHECK(!(json_view() == null_document.root())); // NOLINT(readability-container-size-empty)
-        CHECK(!(null_document.root() == discarded));
-    }
-
-    SECTION("deep nesting")
-    {
-        const std::string deep = std::string(100000, '[') + std::string(100000, ']');
-        const json_document a = json_document::parse(deep);
-        const json_document b = json_document::parse(deep);
-        CHECK(a.root() == b.root());
-        CHECK(a.root() == json::parse(deep));
-        const std::string other = std::string(100000, '[') + "1" + std::string(100000, ']');
-        const json_document c = json_document::parse(other);
-        CHECK(a.root() != c.root());
-    }
-}
-
-TEST_CASE("json_view large objects")
-{
-    // objects with 128 members or more are looked up with a hash index
-    for (const std::size_t members :
-            {
-                127u, 128u, 129u, 10000u
-            })
-    {
-        CAPTURE(members)
-        std::string text = "{";
-        for (std::size_t i = 0; i < members; ++i)
-        {
-            text += (i != 0 ? ",\"" : "\"") + std::string(i % 23, 'k') + std::to_string(i) + (i % 7 == 0 ? "\\n" : "") + "\":" + std::to_string(i);
-        }
-        text += R"(,"":"empty key","k1":"a duplicate of an earlier key"})";
-        const json_document d = json_document::parse(text);
-        const json_view v = d.root();
-        const json j = json::parse(text);
-        for (std::size_t i = 0; i < members; ++i)
-        {
-            const std::string key = std::string(i % 23, 'k') + std::to_string(i) + (i % 7 == 0 ? "\n" : "");
-            CHECK(v[key].get<std::size_t>() == i);
-            CHECK(v.contains(key));
-            CHECK(v.find(key).key() == key);
-            CHECK(v.at(key).get<std::size_t>() == i);
-            CHECK(!v.contains(key + "x"));
-        }
-        CHECK(v[""].get_string() == "empty key");
-        CHECK(v["k1"].get<int>() == 1); // the first of duplicate keys, as for small objects
-        CHECK(!v.contains("missing"));
-        CHECK_THROWS_WITH_AS(v.at("missing"), "[json.exception.out_of_range.403] key 'missing' not found", json::out_of_range&);
-        CHECK(v == j);
-        CHECK(v.materialize() == j);
-    }
-
-    SECTION("duplicate keys: the first member wins, with and without a table")
-    {
-        // an object of `total` members: the keys "k0".."k<n-1>" in order, then
-        // three keys repeated twice more (one copy in the middle, one at the
-        // end), and two keys repeated once; the value of a member is its
-        // position, so that the first member of a key can be told apart
-        struct member
-        {
-            std::string key;
-            std::size_t position;
-        };
-        const auto make_members = [](std::size_t total)
-        {
-            std::vector<std::string> keys;
-            for (std::size_t i = 0; i + 8 < total; ++i)
-            {
-                keys.push_back("k" + std::to_string(i));
-            }
-            const std::size_t n = keys.size();
-            const std::array<std::size_t, 3> triple = {{3, 17, n - 1}};
-            const std::array<std::size_t, 2> twice = {{5, n / 2}};
-            std::vector<std::string> ordered = keys;
-            for (const std::size_t i : triple)
-            {
-                ordered.insert(ordered.begin() + static_cast<std::ptrdiff_t>(ordered.size() / 2), keys[i]);
-            }
-            for (const std::size_t i : twice)
-            {
-                ordered.insert(ordered.begin() + static_cast<std::ptrdiff_t>(ordered.size() / 3), keys[i]);
-            }
-            for (const std::size_t i : triple)
-            {
-                ordered.push_back(keys[i]);
-            }
-            std::vector<member> result;
-            result.reserve(ordered.size());
-            for (std::size_t i = 0; i < ordered.size(); ++i)
-            {
-                result.push_back({ordered[i], i});
-            }
-            return result;
-        };
-
-        // 100 and 127 members: no table; 128 members and more: a table
-        for (const std::size_t total :
-                {
-                    100u, 127u, 128u, 200u, 5000u
-                })
-        {
-            CAPTURE(total)
-            const std::vector<member> members = make_members(total);
-            REQUIRE(members.size() >= total);
-            REQUIRE(members.size() >= 100);
-            std::string text = "{";
-            std::map<std::string, std::size_t> first;
-            std::map<std::string, std::size_t> last;
-            std::map<std::string, std::size_t> occurrences;
-            for (const member& m : members)
-            {
-                text += (text.size() > 1 ? ",\"" : "\"") + m.key + "\":" + std::to_string(m.position);
-                first.insert({m.key, m.position});
-                last[m.key] = m.position;
-                ++occurrences[m.key];
-            }
-            text += '}';
-            REQUIRE(first.size() < members.size());
-
-            const json_document d = json_document::parse(text);
-            const json_view v = d.root();
-            const json j = json::parse(text);
-            CHECK(v.size() == members.size()); // every occurrence is visited
-            const json m = v.materialize();
-            for (const auto& entry : first)
-            {
-                CAPTURE(entry.first)
-                const std::size_t expected = entry.second;
-                CHECK(v[entry.first].get<std::size_t>() == expected);
-                CHECK(v.at(entry.first).get<std::size_t>() == expected);
-                CHECK(v.find(entry.first).value().get<std::size_t>() == expected);
-                CHECK(v.value(entry.first, std::size_t{0}) == expected);
-                CHECK(v.contains(entry.first));
-                CHECK(v.count(entry.first) == occurrences[entry.first]);
-                const std::string pointer = "/" + entry.first;
-                CHECK(v[json::json_pointer(pointer)].get<std::size_t>() == expected);
-                CHECK(v.at(json::json_pointer(pointer)).get<std::size_t>() == expected);
-                CHECK(v.value(json::json_pointer(pointer), std::size_t{0}) == expected);
-                CHECK(v.contains(json::json_pointer(pointer)));
-                // materialize() and parse() keep the last value instead
-                CHECK(j[entry.first].get<std::size_t>() == last.at(entry.first));
-                CHECK(m[entry.first].get<std::size_t>() == last.at(entry.first));
-            }
-            CHECK(!v.contains("k"));
-            CHECK(v["missing"].is_discarded());
-            CHECK(v.materialize() == j);
-            CHECK(v == j);
-        }
-    }
-
-    SECTION("colliding keys")
-    {
-        // the hash is not seeded, so keys that all land in one place must not
-        // make the table build quadratic: such an object gets no table and is
-        // searched linearly
-        constexpr std::size_t members = 300;
-        constexpr std::size_t table_size = 1024; // the table size for 300 members: the next power of two >= 600
-        std::vector<std::string> colliding;
-        std::vector<std::string> spread;
-        for (std::uint64_t counter = 0; colliding.size() < members || spread.size() < members; ++counter)
-        {
-            std::string key(8, 'a');
-            std::uint64_t x = counter;
-            for (std::size_t i = 0; i < 8; ++i, x /= 26)
-            {
-                key[i] = static_cast<char>('a' + (x % 26));
-            }
-            const bool lands_in_slot_zero = (nlohmann::detail::view::key_hash(key.data(), key.size()) & (table_size - 1)) == 0;
-            if (lands_in_slot_zero && colliding.size() < members)
-            {
-                colliding.push_back(key);
-            }
-            else if (!lands_in_slot_zero && spread.size() < members)
-            {
-                spread.push_back(key);
-            }
-        }
-
-        const auto make_text = [](const std::vector<std::string>& keys)
-        {
-            std::string text = "{";
-            for (std::size_t i = 0; i < keys.size(); ++i)
-            {
-                text += (i != 0 ? ",\"" : "\"") + keys[i] + "\":" + std::to_string(i % 10);
-            }
-            return text + "}";
-        };
-        const std::string colliding_text = make_text(colliding);
-        const std::string spread_text = make_text(spread);
-
-        json_document with_collisions = json_document::parse(colliding_text);
-        json_document without_collisions = json_document::parse(spread_text);
-        for (const auto* pair :
-                {
-                    &colliding, &spread
-                })
-        {
-            const json_view v = (pair == &colliding ? with_collisions : without_collisions).root();
-            for (std::size_t i = 0; i < members; ++i)
-            {
-                CAPTURE(i)
-                CHECK(v[(*pair)[i]].get<std::size_t>() == i % 10);
-                CHECK(v.at((*pair)[i]).get<std::size_t>() == i % 10);
-                CHECK(v.find((*pair)[i]).key() == (*pair)[i]);
-                CHECK(!v.contains((*pair)[i] + "x"));
-            }
-            CHECK(!v.contains("missing"));
-        }
-        CHECK(with_collisions.root() == json::parse(colliding_text));
-
-        // only the object with the spread keys got a table (both texts have the
-        // same length, so the tables are the only difference)
-        with_collisions.shrink_to_fit();
-        without_collisions.shrink_to_fit();
-        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 = nlohmann::detail::conditional_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); // NOLINT(abseil-string-find-str-contains)
-            CHECK(max_displacement(numbered(format, 600, 7)) < nlohmann::detail::view::index_max_displacement);
-        }
-        std::mt19937_64 rng(7); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
-        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;
-            // (there are 26 and 676 keys of one and two letters)
-            std::size_t wanted = 700;
-            if (length == 1)
-            {
-                wanted = 26;
-            }
-            else if (length == 2)
-            {
-                wanted = 500;
-            }
-            while (distinct.size() < wanted)
-            {
-                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); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
-        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)
-        {
-            std::string text = "[";
-            for (int object = 0; object < objects; ++object)
-            {
-                text += object != 0 ? ",{" : "{";
-                for (int i = 0, n = members + object; i < n; ++i)
-                {
-                    text += (i != 0 ? ",\"" : "\"") + std::to_string(i) + "\":" + std::to_string(i);
-                }
-                text += '}';
-            }
-            return text + "]";
-        };
-        const std::string small_text = make_text(5, 150);
-        const std::string big_text = make_text(40, 400);
-
-        // reading a big text, and then a small one, leaves the spare capacity
-        // of the big one: shrink_to_fit() brings the document to the size of
-        // one parsed from the small text alone
-        json_document d = json_document::parse(big_text);
-        const std::size_t big = d.memory_usage();
-        d.read(small_text);
-        CHECK(d.memory_usage() >= big);
-        d.shrink_to_fit();
-        json_document fresh = json_document::parse(small_text);
-        fresh.shrink_to_fit();
-        CHECK(d.memory_usage() == fresh.memory_usage());
-        CHECK(d.memory_usage() < big / 2);
-        CHECK(d.root() == json::parse(small_text));
-        for (int object = 0; object < 5; ++object)
-        {
-            const json_view v = d.root()[static_cast<std::size_t>(object)];
-            for (int i = 0, n = 150 + object; i < n; ++i)
-            {
-                CHECK(v[std::to_string(i)].get<int>() == i);
-            }
-        }
-    }
-
-    SECTION("nested, reused, and in arrays")
-    {
-        std::string inner = "{";
-        for (int i = 0; i < 300; ++i)
-        {
-            inner += (i != 0 ? ",\"m" : "\"m") + std::to_string(i) + "\":" + std::to_string(i);
-        }
-        inner += '}';
-        const std::string text = "[" + inner + ",{\"x\":" + inner + "}," + inner + "]";
-        json_document d = json_document::parse(text);
-        CHECK(d.root()[0]["m299"].get<int>() == 299);
-        CHECK(d.root()[1]["x"]["m150"].get<int>() == 150);
-        CHECK(d.root()[2]["m0"].get<int>() == 0);
-        const std::size_t with_index = d.memory_usage();
-        d.read(std::string("{\"small\": 1}"));
-        CHECK(d.root()["small"].get<int>() == 1);
-        d.read(text);
-        CHECK(d.root()[2]["m7"].get<int>() == 7);
-        CHECK(d.memory_usage() >= with_index / 2);
-    }
 }
@@ -0,0 +1,298 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#include "doctest_compatibility.h"
+
+#include <nlohmann/json_view.hpp>
+using nlohmann::json;
+using nlohmann::ordered_json;
+using nlohmann::json_document;
+using nlohmann::ordered_json_editable_document;
+using nlohmann::json_view;
+using nlohmann::ordered_json_document;
+using nlohmann::ordered_json_view;
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <iomanip>
+#include <map>
+#include <random>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+
+// These tests were split off unit-json_view_dump.cpp, whose object file got too large for the MinGW
+// linker (see json_view_test_helpers.hpp). Like that file, this one is also built
+// with C++17, as it mentions JSON_HAS_CPP_17.
+
+TEST_CASE("json_view dump: escaping, nesting, and output buffers")
+{
+    SECTION("members in document order, all of them")
+    {
+        const json_document d = json_document::parse(R"({"b": 1, "a": 2, "b": 3})");
+        CHECK(d.root().dump() == R"({"b":1,"a":2,"b":3})");
+        CHECK(d.root().dump(1) == "{\n \"b\": 1,\n \"a\": 2,\n \"b\": 3\n}");
+        // dump() writes all members, though the lookup finds the first
+        CHECK(d.root()["b"].dump() == "1");
+    }
+
+    SECTION("deep nesting")
+    {
+        const std::string deep = std::string(100000, '[') + std::string(100000, ']');
+        const json_document deep_document = json_document::parse(deep);
+        CHECK(deep_document.root().dump() == deep);
+    }
+
+    SECTION("ensure_ascii: a character that needs an escape at each position of a string")
+    {
+        // string lengths around the width of the vector steps, in a string value, a key, and a value near the end of the text
+        for (const char* const special :
+                {
+                    "\xC3\xA9", "\xE4\xB8\xAD", "\xF0\x9F\x98\x80", "\x7F", "\\n", "\\u0001", "\\\"", "\\\\"
+                })
+        {
+            for (std::size_t length = 0; length <= 40; ++length)
+            {
+                for (std::size_t position = 0; position <= length; ++position)
+                {
+                    std::string content(length, 'a');
+                    content.insert(position, special);
+                    const std::array<std::string, 3> texts =
+                    {
+                        {
+                            "\"" + content + "\"",
+                            "[\"" + content + "\"]",
+                            "{\"" + content + "\":1}",
+                        }
+                    };
+                    for (const std::string& text : texts)
+                    {
+                        CAPTURE(text)
+                        const ordered_json_document d = ordered_json_document::parse(text);
+                        const ordered_json j = ordered_json::parse(text);
+                        CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
+                        CHECK(d.root().dump(2, ' ', true) == j.dump(2, ' ', true));
+                        CHECK(d.root().dump() == j.dump());
+                    }
+                }
+            }
+        }
+    }
+
+    SECTION("ensure_ascii: every character of the Basic Multilingual Plane and some beyond")
+    {
+        // (the two- and three-byte sequences, including the ranges that need a check: E0, ED, EF BF BF)
+        std::string text = "[";
+        std::size_t in_chunk = 0;
+        const auto append = [&](std::uint32_t cp)
+        {
+            if (cp < 0x80)
+            {
+                if (cp < 0x20 || cp == '"' || cp == '\\')
+                {
+                    return;
+                }
+                text += static_cast<char>(cp);
+            }
+            else if (cp < 0x800)
+            {
+                text += static_cast<char>(0xC0 | (cp >> 6));
+                text += static_cast<char>(0x80 | (cp & 0x3F));
+            }
+            else if (cp < 0x10000)
+            {
+                text += static_cast<char>(0xE0 | (cp >> 12));
+                text += static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
+                text += static_cast<char>(0x80 | (cp & 0x3F));
+            }
+            else
+            {
+                text += static_cast<char>(0xF0 | (cp >> 18));
+                text += static_cast<char>(0x80 | ((cp >> 12) & 0x3F));
+                text += static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
+                text += static_cast<char>(0x80 | (cp & 0x3F));
+            }
+        };
+        for (std::uint32_t cp = 0x20; cp < 0x10400; ++cp)
+        {
+            if (cp >= 0xD800 && cp < 0xE000)
+            {
+                continue;
+            }
+            if (in_chunk == 0)
+            {
+                text += text.size() > 1 ? ",\"" : "\"";
+            }
+            append(cp);
+            if (++in_chunk == 37)
+            {
+                text += "\"";
+                in_chunk = 0;
+            }
+        }
+        text += in_chunk != 0 ? "\"]" : "]";
+        const ordered_json_document d = ordered_json_document::parse(text);
+        const ordered_json j = ordered_json::parse(text);
+        CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
+        CHECK(d.root().dump(2, ' ', true) == j.dump(2, ' ', true));
+        CHECK(d.root().dump() == j.dump());
+        CHECK(d.root().dump(2) == j.dump(2));
+    }
+
+    SECTION("deep nesting, indented")
+    {
+        // indentations of up to and beyond the width of the writer's fixed-size copy
+        for (const int depth :
+                {
+                    1, 5, 20, 70, 300
+                })
+        {
+            std::string text;
+            for (int i = 0; i < depth; ++i)
+            {
+                text += i % 2 == 0 ? "[1," : R"({"k":2,"\u00e9":)";
+            }
+            text += "[]";
+            for (int i = depth - 1; i >= 0; --i)
+            {
+                text += i % 2 == 0 ? "]" : "}";
+            }
+            const ordered_json_document d = ordered_json_document::parse(text);
+            const ordered_json j = ordered_json::parse(text);
+            for (const int indent :
+                    {
+                        0, 1, 2, 3, 8
+                    })
+            {
+                CHECK(d.root().dump(indent) == j.dump(indent));
+                CHECK(d.root().dump(indent, '\t') == j.dump(indent, '\t'));
+            }
+        }
+    }
+
+    SECTION("the output buffer of a small value is small")
+    {
+        // an escaped key after the value: its node lies in the arena, so the
+        // source extent of the value cannot be read from the next node
+        const std::string big(100000, 'a');
+        const std::string text = R"({"small":1,"list":[1,2,3],"k\n":")" + big + R"("})";
+        const json_document d = json_document::parse(text);
+        const auto small = d.root()["small"].dump();
+        CHECK(small == "1");
+        CHECK(small.capacity() < 4096);
+        const auto list = d.root()["list"].dump();
+        CHECK(list == "[1,2,3]");
+        CHECK(list.capacity() < 4096);
+        CHECK(d.root()["list"].dump(2).capacity() < 4096);
+
+        // the whole document and the large value are unaffected
+        CHECK(d.root().dump() == ordered_json::parse(text).dump());
+        CHECK(d.root()["k\n"].dump() == "\"" + big + "\"");
+    }
+
+    SECTION("output that outgrows the estimate")
+    {
+        // ensure_ascii writes six bytes for each two-byte character
+        std::string chars;
+        for (int i = 0; i < 5000; ++i)
+        {
+            chars += "\xC3\xA9";
+        }
+        const json_document d = json_document::parse(R"({"a":")" + chars + R"(","k\n":1})");
+        const json expected = json::parse("\"" + chars + "\"");
+        CHECK(d.root()["a"].dump(-1, ' ', true) == expected.dump(-1, ' ', true));
+        CHECK(d.root()["a"].dump(-1, ' ', true).size() == 2 + (5000 * 6));
+    }
+
+    SECTION("ensure_ascii with strings of the source, decoded strings, and edited strings")
+    {
+        // plain ASCII, non-ASCII, escaped (decoded), and mixed strings, as values and as keys;
+        // the second text has a DEL, which ensure_ascii writes as an escape
+        for (const char* const del :
+                {"", "\x7F"
+                })
+        {
+            const std::string text = std::string("{\"plain\":\"abc\",\"caf\xC3\xA9\":\"\xC3\xA9\xE2\x82\xAC\xF0\x9F\x98\x80\",")
+                                     + "\"esc\\n\\\"\":\"a\\tb\\u00e4\\ud83d\\ude00\",\"del\":\"a" + del + "b\",\"\":\"\"," // NOLINT(modernize-raw-string-literal)
+                                     + "\"list\":[\"x\",\"\xC3\xBC\",\"\\\\\",\"long ASCII string with more than thirty-two bytes in it\","
+                                     + "\"long string with more than thirty-two bytes and one non-ASCII byte \xC3\xB6\"],"
+                                     + "\"n\":[1,2.5,-0,true,null]}";
+            const ordered_json j = ordered_json::parse(text);
+            const ordered_json_document d = ordered_json_document::parse(text);
+            CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
+            CHECK(d.root().dump(4, ' ', true) == j.dump(4, ' ', true));
+            CHECK(d.root().dump() == j.dump());
+            CHECK(d.root()["list"].dump(-1, ' ', true) == j["list"].dump(-1, ' ', true));
+            CHECK(d.root()["del"].dump(-1, ' ', true) == j["del"].dump(-1, ' ', true));
+
+            // strings that an edit wrote (the source strings that they replace were plain)
+            ordered_json_editable_document e = ordered_json_editable_document::parse(text);
+            ordered_json k = j;
+            e.set(e.root()["plain"], std::string("\xC3\xA4gypten"));
+            k["plain"] = "\xC3\xA4gypten";
+            e.set(e.root()["list"][0], std::string("ascii after edit"));
+            k["list"][0] = "ascii after edit";
+            e.set(e.root()["list"][1], std::string("\xC3\xA4"));
+            k["list"][1] = "\xC3\xA4";
+            e.set(e.root()["del"], std::string("tab\there"));
+            k["del"] = "tab\there";
+            CHECK(e.root().dump(-1, ' ', true) == k.dump(-1, ' ', true));
+            CHECK(e.root().dump(2, ' ', true) == k.dump(2, ' ', true));
+            CHECK(e.root().dump() == k.dump());
+
+            // strings that were edited from or to ASCII text
+            e.set(e.root()["list"][2], std::string("\xC3\xA4"));
+            k["list"][2] = "\xC3\xA4";
+            e.set(e.root()["list"][4], std::string("plain again"));
+            k["list"][4] = "plain again";
+            CHECK(e.root().dump(-1, ' ', true) == k.dump(-1, ' ', true));
+        }
+    }
+
+    SECTION("ensure_ascii with DEL or a non-ASCII character at every position")
+    {
+        // the check whether a string of the source has no byte >= 0x7F reads
+        // eight bytes at a time and then the rest one by one
+        for (std::size_t length = 1; length <= 20; ++length)
+        {
+            for (std::size_t pos = 0; pos < length; ++pos)
+            {
+                for (const char* const c :
+                        {
+                            "\x7F", "\x7E", "\xC3\xA4", "\xC3\xBF" // NOLINT(modernize-raw-string-literal)
+                        })
+                {
+                    const std::string s = std::string(pos, 'a') + c + std::string(length - pos - 1, 'b');
+                    std::string text = "[\"";
+                    text.append(s).append("\",{\"").append(s).append("\":1}]");
+                    const json_document d = json_document::parse(text);
+                    const json j = json::parse(text);
+                    CHECK(d.root().dump(-1, ' ', true) == j.dump(-1, ' ', true));
+                    CHECK(d.root().dump(1, ' ', true) == j.dump(1, ' ', true));
+                }
+            }
+        }
+    }
+
+    SECTION("streams and discarded views")
+    {
+        const json_document d = json_document::parse(R"({"a": [1, 2]})");
+        std::ostringstream compact;
+        compact << d.root();
+        CHECK(compact.str() == R"({"a":[1,2]})");
+        std::ostringstream pretty;
+        pretty << std::setw(2) << std::setfill('.') << d.root() << d.root()["a"];
+        CHECK(pretty.str() == "{\n..\"a\": [\n....1,\n....2\n..]\n}[1,2]");
+        CHECK(json_view().dump() == json(json::value_t::discarded).dump());
+    }
+}
@@ -326,8 +326,7 @@ TEST_CASE("json_view from_json")
        CHECK(d.root().get<std::unordered_map<std::string, int>>().at("a") == 3);
    }

-// (the exceptions of views have neither the path nor the byte range of the value)
-#if !defined(JSON_NOEXCEPTION) && !JSON_DIAGNOSTICS && !JSON_DIAGNOSTIC_POSITIONS
+#if !defined(JSON_NOEXCEPTION) && !JSON_DIAGNOSTICS
    SECTION("std types: the same errors as from the materialized value")
    {
        const json_document d = json_document::parse(R"([[1, "x"], {"a": 1}, "text", [1], 5, null])");
@@ -393,7 +392,7 @@ TEST_CASE("json_view from_json")
 #if !defined(JSON_NOEXCEPTION)
        const json j = d.root().materialize();
        CHECK(exception_of_call([&] { static_cast<void>(d.root()[2].get<strict_color>()); }) == "[json.exception.out_of_range.410] enum value out of range for strict_color: \"purple\"");
-#if !JSON_DIAGNOSTICS && !JSON_DIAGNOSTIC_POSITIONS
+#if !JSON_DIAGNOSTICS
        CHECK(exception_of_call([&] { static_cast<void>(d.root()[2].get<strict_color>()); }) == exception_of_call([&] { static_cast<void>(j[2].get<strict_color>()); }));
 #endif
 #endif
@@ -441,11 +440,10 @@ TEST_CASE("json_view from_json")
        CHECK(o.root().get<shape>().center.y == 2);
    }

-#if !defined(JSON_NOEXCEPTION) && !JSON_DIAGNOSTICS && !JSON_DIAGNOSTIC_POSITIONS
+#if !defined(JSON_NOEXCEPTION) && !JSON_DIAGNOSTICS
    SECTION("errors are those of the same conversion of a json value")
    {
-        // (with JSON_DIAGNOSTICS, those of json name the path of the value,
-        // and with JSON_DIAGNOSTIC_POSITIONS its bytes)
+        // (with JSON_DIAGNOSTICS, those of json name the path of the value)
        const json_document d = json_document::parse(R"([{"x": 1}, {"x": "1", "y": 2}, [1, 2], {"id": "7", "c": "red"}])");
        const json j = d.root().materialize();
        for (std::size_t i = 0; i < 3; ++i)
@@ -0,0 +1,544 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
+// |  |  |__   |  |  | | | |  version 3.12.0
+// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
+//
+// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
+// SPDX-License-Identifier: MIT
+
+#include "doctest_compatibility.h"
+
+#include <nlohmann/json_view.hpp>
+using nlohmann::json;
+using nlohmann::ordered_json;
+using nlohmann::json_document;
+using nlohmann::ordered_json_editable_document;
+using nlohmann::json_view;
+using nlohmann::ordered_json_document;
+using nlohmann::ordered_json_view;
+
+#include "json_view_test_helpers.hpp"
+using json_view_test::generator;
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <iomanip>
+#include <map>
+#include <random>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+
+// These tests were split off unit-json_view_dump.cpp, whose object file got too large for the MinGW
+// linker (see json_view_test_helpers.hpp). Like that file, this one is also built
+// with C++17, as it mentions JSON_HAS_CPP_17.
+
+TEST_CASE("json_view comparison")
+{
+    SECTION("equality of the values parse() produces")
+    {
+        generator g;
+        std::vector<std::string> texts;
+        for (int i = 0; i < 600; ++i)
+        {
+            std::string text;
+            g.value(text, 0);
+            texts.push_back(text);
+            // the same value written differently: sorted keys, canonical numbers
+            texts.push_back(json::parse(text).dump(1));
+        }
+        for (std::size_t i = 0; i + 2 < texts.size(); ++i)
+        {
+            for (std::size_t k = i; k < i + 3; ++k)
+            {
+                CAPTURE(texts[i])
+                CAPTURE(texts[k])
+                const json_document a = json_document::parse(texts[i]);
+                const json_document b = json_document::parse(texts[k]);
+                const json ja = json::parse(texts[i]);
+                const json jb = json::parse(texts[k]);
+                CHECK((a.root() == b.root()) == (ja == jb));
+                CHECK((a.root() != b.root()) == (ja != jb));
+                CHECK((a.root() == jb) == (ja == jb));
+                CHECK((jb == a.root()) == (ja == jb));
+                CHECK((a.root() != jb) == (ja != jb));
+                CHECK((jb != a.root()) == (ja != jb));
+
+                // ordered_json compares members in order
+                const ordered_json_document oa = ordered_json_document::parse(texts[i]);
+                const ordered_json_document ob = ordered_json_document::parse(texts[k]);
+                const ordered_json oja = ordered_json::parse(texts[i]);
+                const ordered_json ojb = ordered_json::parse(texts[k]);
+                CHECK((oa.root() == ob.root()) == (oja == ojb));
+                CHECK((oa.root() == ojb) == (oja == ojb));
+            }
+        }
+    }
+
+    SECTION("numbers, duplicate keys, member order")
+    {
+        const auto same = [](const char* x, const char* y)
+        {
+            const json_document dx = json_document::parse(x);
+            const json_document dy = json_document::parse(y);
+            return dx.root() == dy.root();
+        };
+        CHECK(same("1", "1.0"));
+        CHECK(same("[1, -1, 2.5]", "[1.0, -1.0, 25e-1]"));
+        CHECK(!same("1", "1.5"));
+        CHECK(same("18446744073709551615", "18446744073709551615"));
+        CHECK(same(R"({"a": 1, "a": 2})", R"({"a": 2})"));
+        CHECK(!same(R"({"a": 1, "a": 2})", R"({"a": 1})"));
+        CHECK(same(R"({"a": 1, "b": 2})", R"({"b": 2, "a": 1})"));
+        CHECK(!same(R"({"a": 1})", R"({"a": 1, "b": 2})"));
+        CHECK(!same("[1, 2]", "[2, 1]"));
+        CHECK(!same("\"a\"", "\"b\""));
+        CHECK(same("\"\\u00e9\"", "\"\xc3\xa9\""));
+        CHECK(!same("null", "false"));
+        CHECK(!same("[]", "{}"));
+        const ordered_json_document dup = ordered_json_document::parse(R"({"a": 1, "b": 2, "a": 3})");
+        const ordered_json_document last = ordered_json_document::parse(R"({"a": 3, "b": 2})");
+        CHECK(dup.root() == last.root());
+        // (== compares as parse() resolves duplicates, a lookup finds the first)
+        CHECK(dup.root()["a"].materialize() == 1);
+        CHECK(dup.root()["a"] != last.root()["a"]);
+        const ordered_json_document ab = ordered_json_document::parse(R"({"a": 1, "b": 2})");
+        const ordered_json_document ba = ordered_json_document::parse(R"({"b": 2, "a": 1})");
+        CHECK(ab.root() != ba.root());
+
+        // discarded values compare as basic_json's do
+        const json discarded(json::value_t::discarded);
+        CHECK((json_view() == json_view()) == (discarded == discarded)); // NOLINT(readability-container-size-empty): operator== is tested
+        CHECK((json_view() == discarded) == (discarded == discarded)); // NOLINT(readability-container-size-empty)
+        const json_document null_document = json_document::parse("null");
+        CHECK(!(json_view() == null_document.root())); // NOLINT(readability-container-size-empty)
+        CHECK(!(null_document.root() == discarded));
+    }
+
+    SECTION("deep nesting")
+    {
+        const std::string deep = std::string(100000, '[') + std::string(100000, ']');
+        const json_document a = json_document::parse(deep);
+        const json_document b = json_document::parse(deep);
+        CHECK(a.root() == b.root());
+        CHECK(a.root() == json::parse(deep));
+        const std::string other = std::string(100000, '[') + "1" + std::string(100000, ']');
+        const json_document c = json_document::parse(other);
+        CHECK(a.root() != c.root());
+    }
+}
+
+TEST_CASE("json_view large objects")
+{
+    // objects with 128 members or more are looked up with a hash index
+    for (const std::size_t members :
+            {
+                127u, 128u, 129u, 10000u
+            })
+    {
+        CAPTURE(members)
+        std::string text = "{";
+        for (std::size_t i = 0; i < members; ++i)
+        {
+            text += (i != 0 ? ",\"" : "\"") + std::string(i % 23, 'k') + std::to_string(i) + (i % 7 == 0 ? "\\n" : "") + "\":" + std::to_string(i);
+        }
+        text += R"(,"":"empty key","k1":"a duplicate of an earlier key"})";
+        const json_document d = json_document::parse(text);
+        const json_view v = d.root();
+        const json j = json::parse(text);
+        for (std::size_t i = 0; i < members; ++i)
+        {
+            const std::string key = std::string(i % 23, 'k') + std::to_string(i) + (i % 7 == 0 ? "\n" : "");
+            CHECK(v[key].get<std::size_t>() == i);
+            CHECK(v.contains(key));
+            CHECK(v.find(key).key() == key);
+            CHECK(v.at(key).get<std::size_t>() == i);
+            CHECK(!v.contains(key + "x"));
+        }
+        CHECK(v[""].get_string() == "empty key");
+        CHECK(v["k1"].get<int>() == 1); // the first of duplicate keys, as for small objects
+        CHECK(!v.contains("missing"));
+        CHECK_THROWS_WITH_AS(v.at("missing"), "[json.exception.out_of_range.403] key 'missing' not found", json::out_of_range&);
+        CHECK(v == j);
+        CHECK(v.materialize() == j);
+    }
+
+    SECTION("duplicate keys: the first member wins, with and without a table")
+    {
+        // an object of `total` members: the keys "k0".."k<n-1>" in order, then
+        // three keys repeated twice more (one copy in the middle, one at the
+        // end), and two keys repeated once; the value of a member is its
+        // position, so that the first member of a key can be told apart
+        struct member
+        {
+            std::string key;
+            std::size_t position;
+        };
+        const auto make_members = [](std::size_t total)
+        {
+            std::vector<std::string> keys;
+            for (std::size_t i = 0; i + 8 < total; ++i)
+            {
+                keys.push_back("k" + std::to_string(i));
+            }
+            const std::size_t n = keys.size();
+            const std::array<std::size_t, 3> triple = {{3, 17, n - 1}};
+            const std::array<std::size_t, 2> twice = {{5, n / 2}};
+            std::vector<std::string> ordered = keys;
+            for (const std::size_t i : triple)
+            {
+                ordered.insert(ordered.begin() + static_cast<std::ptrdiff_t>(ordered.size() / 2), keys[i]);
+            }
+            for (const std::size_t i : twice)
+            {
+                ordered.insert(ordered.begin() + static_cast<std::ptrdiff_t>(ordered.size() / 3), keys[i]);
+            }
+            for (const std::size_t i : triple)
+            {
+                ordered.push_back(keys[i]);
+            }
+            std::vector<member> result;
+            result.reserve(ordered.size());
+            for (std::size_t i = 0; i < ordered.size(); ++i)
+            {
+                result.push_back({ordered[i], i});
+            }
+            return result;
+        };
+
+        // 100 and 127 members: no table; 128 members and more: a table
+        for (const std::size_t total :
+                {
+                    100u, 127u, 128u, 200u, 5000u
+                })
+        {
+            CAPTURE(total)
+            const std::vector<member> members = make_members(total);
+            REQUIRE(members.size() >= total);
+            REQUIRE(members.size() >= 100);
+            std::string text = "{";
+            std::map<std::string, std::size_t> first;
+            std::map<std::string, std::size_t> last;
+            std::map<std::string, std::size_t> occurrences;
+            for (const member& m : members)
+            {
+                text += (text.size() > 1 ? ",\"" : "\"") + m.key + "\":" + std::to_string(m.position);
+                first.insert({m.key, m.position});
+                last[m.key] = m.position;
+                ++occurrences[m.key];
+            }
+            text += '}';
+            REQUIRE(first.size() < members.size());
+
+            const json_document d = json_document::parse(text);
+            const json_view v = d.root();
+            const json j = json::parse(text);
+            CHECK(v.size() == members.size()); // every occurrence is visited
+            const json m = v.materialize();
+            for (const auto& entry : first)
+            {
+                CAPTURE(entry.first)
+                const std::size_t expected = entry.second;
+                CHECK(v[entry.first].get<std::size_t>() == expected);
+                CHECK(v.at(entry.first).get<std::size_t>() == expected);
+                CHECK(v.find(entry.first).value().get<std::size_t>() == expected);
+                CHECK(v.value(entry.first, std::size_t{0}) == expected);
+                CHECK(v.contains(entry.first));
+                CHECK(v.count(entry.first) == occurrences[entry.first]);
+                const std::string pointer = "/" + entry.first;
+                CHECK(v[json::json_pointer(pointer)].get<std::size_t>() == expected);
+                CHECK(v.at(json::json_pointer(pointer)).get<std::size_t>() == expected);
+                CHECK(v.value(json::json_pointer(pointer), std::size_t{0}) == expected);
+                CHECK(v.contains(json::json_pointer(pointer)));
+                // materialize() and parse() keep the last value instead
+                CHECK(j[entry.first].get<std::size_t>() == last.at(entry.first));
+                CHECK(m[entry.first].get<std::size_t>() == last.at(entry.first));
+            }
+            CHECK(!v.contains("k"));
+            CHECK(v["missing"].is_discarded());
+            CHECK(v.materialize() == j);
+            CHECK(v == j);
+        }
+    }
+
+    SECTION("colliding keys")
+    {
+        // the hash is not seeded, so keys that all land in one place must not
+        // make the table build quadratic: such an object gets no table and is
+        // searched linearly
+        constexpr std::size_t members = 300;
+        constexpr std::size_t table_size = 1024; // the table size for 300 members: the next power of two >= 600
+        std::vector<std::string> colliding;
+        std::vector<std::string> spread;
+        for (std::uint64_t counter = 0; colliding.size() < members || spread.size() < members; ++counter)
+        {
+            std::string key(8, 'a');
+            std::uint64_t x = counter;
+            for (std::size_t i = 0; i < 8; ++i, x /= 26)
+            {
+                key[i] = static_cast<char>('a' + (x % 26));
+            }
+            const bool lands_in_slot_zero = (nlohmann::detail::view::key_hash(key.data(), key.size()) & (table_size - 1)) == 0;
+            if (lands_in_slot_zero && colliding.size() < members)
+            {
+                colliding.push_back(key);
+            }
+            else if (!lands_in_slot_zero && spread.size() < members)
+            {
+                spread.push_back(key);
+            }
+        }
+
+        const auto make_text = [](const std::vector<std::string>& keys)
+        {
+            std::string text = "{";
+            for (std::size_t i = 0; i < keys.size(); ++i)
+            {
+                text += (i != 0 ? ",\"" : "\"") + keys[i] + "\":" + std::to_string(i % 10);
+            }
+            return text + "}";
+        };
+        const std::string colliding_text = make_text(colliding);
+        const std::string spread_text = make_text(spread);
+
+        json_document with_collisions = json_document::parse(colliding_text);
+        json_document without_collisions = json_document::parse(spread_text);
+        for (const auto* pair :
+                {
+                    &colliding, &spread
+                })
+        {
+            const json_view v = (pair == &colliding ? with_collisions : without_collisions).root();
+            for (std::size_t i = 0; i < members; ++i)
+            {
+                CAPTURE(i)
+                CHECK(v[(*pair)[i]].get<std::size_t>() == i % 10);
+                CHECK(v.at((*pair)[i]).get<std::size_t>() == i % 10);
+                CHECK(v.find((*pair)[i]).key() == (*pair)[i]);
+                CHECK(!v.contains((*pair)[i] + "x"));
+            }
+            CHECK(!v.contains("missing"));
+        }
+        CHECK(with_collisions.root() == json::parse(colliding_text));
+
+        // only the object with the spread keys got a table (both texts have the
+        // same length, so the tables are the only difference)
+        with_collisions.shrink_to_fit();
+        without_collisions.shrink_to_fit();
+        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 = nlohmann::detail::conditional_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); // NOLINT(abseil-string-find-str-contains)
+            CHECK(max_displacement(numbered(format, 600, 7)) < nlohmann::detail::view::index_max_displacement);
+        }
+        std::mt19937_64 rng(7); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
+        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;
+            // (there are 26 and 676 keys of one and two letters)
+            std::size_t wanted = 700;
+            if (length == 1)
+            {
+                wanted = 26;
+            }
+            else if (length == 2)
+            {
+                wanted = 500;
+            }
+            while (distinct.size() < wanted)
+            {
+                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); // NOLINT(cert-msc32-c,cert-msc51-cpp,bugprone-random-generator-seed)
+        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)
+        {
+            std::string text = "[";
+            for (int object = 0; object < objects; ++object)
+            {
+                text += object != 0 ? ",{" : "{";
+                for (int i = 0, n = members + object; i < n; ++i)
+                {
+                    text += (i != 0 ? ",\"" : "\"") + std::to_string(i) + "\":" + std::to_string(i);
+                }
+                text += '}';
+            }
+            return text + "]";
+        };
+        const std::string small_text = make_text(5, 150);
+        const std::string big_text = make_text(40, 400);
+
+        // reading a big text, and then a small one, leaves the spare capacity
+        // of the big one: shrink_to_fit() brings the document to the size of
+        // one parsed from the small text alone
+        json_document d = json_document::parse(big_text);
+        const std::size_t big = d.memory_usage();
+        d.read(small_text);
+        CHECK(d.memory_usage() >= big);
+        d.shrink_to_fit();
+        json_document fresh = json_document::parse(small_text);
+        fresh.shrink_to_fit();
+        CHECK(d.memory_usage() == fresh.memory_usage());
+        CHECK(d.memory_usage() < big / 2);
+        CHECK(d.root() == json::parse(small_text));
+        for (int object = 0; object < 5; ++object)
+        {
+            const json_view v = d.root()[static_cast<std::size_t>(object)];
+            for (int i = 0, n = 150 + object; i < n; ++i)
+            {
+                CHECK(v[std::to_string(i)].get<int>() == i);
+            }
+        }
+    }
+
+    SECTION("nested, reused, and in arrays")
+    {
+        std::string inner = "{";
+        for (int i = 0; i < 300; ++i)
+        {
+            inner += (i != 0 ? ",\"m" : "\"m") + std::to_string(i) + "\":" + std::to_string(i);
+        }
+        inner += '}';
+        const std::string text = "[" + inner + ",{\"x\":" + inner + "}," + inner + "]";
+        json_document d = json_document::parse(text);
+        CHECK(d.root()[0]["m299"].get<int>() == 299);
+        CHECK(d.root()[1]["x"]["m150"].get<int>() == 150);
+        CHECK(d.root()[2]["m0"].get<int>() == 0);
+        const std::size_t with_index = d.memory_usage();
+        d.read(std::string("{\"small\": 1}"));
+        CHECK(d.root()["small"].get<int>() == 1);
+        d.read(text);
+        CHECK(d.root()[2]["m7"].get<int>() == 7);
+        CHECK(d.memory_usage() >= with_index / 2);
+    }
+}
@@ -1,340 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-// source positions of materialize() (JSON_DIAGNOSTIC_POSITIONS, #5864)
-
-#include "doctest_compatibility.h"
-
-#ifndef JSON_DIAGNOSTICS
-    #define JSON_DIAGNOSTICS 1
-#endif
-#define JSON_DIAGNOSTIC_POSITIONS 1
-#include <nlohmann/json_view.hpp>
-using nlohmann::json;
-using nlohmann::ordered_json;
-using nlohmann::json_document;
-using nlohmann::json_editable_document;
-
-#include <cstdint>
-#include <cstring>
-#include <fstream>
-#include <sstream>
-#include <string>
-#include <vector>
-
-#include "json_view_test_helpers.hpp"
-#include <test_data.hpp>
-
-namespace
-{
-constexpr std::size_t npos = std::string::npos;
-
-// whether every value of a has the source positions of the value of b at the
-// same place (a and b are equal; shallow test documents only)
-template<typename BasicJsonType>
-bool same_positions(const BasicJsonType& a, const BasicJsonType& b)
-{
-    if (a.start_pos() != b.start_pos() || a.end_pos() != b.end_pos() || a.type() != b.type() || a.size() != b.size())
-    {
-        return false;
-    }
-    if (a.is_object())
-    {
-        for (auto it = a.begin(); it != a.end(); ++it)
-        {
-            if (!same_positions(it.value(), b.at(it.key())))
-            {
-                return false;
-            }
-        }
-    }
-    else if (a.is_array())
-    {
-        for (std::size_t i = 0; i < a.size(); ++i)
-        {
-            if (!same_positions(a[i], b[i]))
-            {
-                return false;
-            }
-        }
-    }
-    return true;
-}
-
-// the materialized root of text has the positions of parse()
-template<typename BasicJsonType>
-bool positions_as_parse(const std::string& text, bool comments = false, bool trailing_commas = false)
-{
-    const auto j = BasicJsonType::parse(text, nullptr, true, comments, trailing_commas);
-    const auto d = nlohmann::basic_json_document<BasicJsonType>::parse(text, true, comments, trailing_commas);
-    const auto e = nlohmann::basic_json_document<BasicJsonType, nlohmann::view_mode::editable>::parse(text, true, comments, trailing_commas);
-    return same_positions(d.root().materialize(), j) && same_positions(e.root().materialize(), j);
-}
-
-std::string range(const json& j)
-{
-    return j.start_pos() == npos && j.end_pos() == npos ? "none" : std::to_string(j.start_pos()) + "-" + std::to_string(j.end_pos());
-}
-} // namespace
-
-TEST_CASE("json_view materialize() source positions")
-{
-    SECTION("as parse()")
-    {
-        const std::vector<std::string> texts =
-        {
-            "null", "true", "false", "0", "-12", "3.25e-2", "18446744073709551615", "-9223372036854775809", R"("a")",
-            R"("\n")", R"("\u00e9")", R"("\ud83d\ude00")", "\"\xf0\x9f\x98\x80\"", R"("a\"b\\")", R"("x\\")",
-            "  [ ]  ", "{}", "[[[]]]", R"({"a":{"b":[1,{"c":[]}]}})",
-            R"({"\u0041": "v\n", "k": "\"", "\t":[ "\/" ]})",
-            "[1, 2.5, true, false, null, \"s\", \"\\u0000\", -0]",
-            "\n\t[\r\n  1 ,\n  {\n    \"a\" : [ ]\n  }\n]\n",
-            "\xef\xbb\xbf[1, {\"a\": \"b\"}]", "\xef\xbb\xbf\"\\n\"",
-        };
-        for (const auto& text : texts)
-        {
-            CAPTURE(text)
-            CHECK(positions_as_parse<json>(text));
-            CHECK(positions_as_parse<ordered_json>(text));
-        }
-    }
-
-    SECTION("comments and trailing commas")
-    {
-        const std::vector<std::string> texts =
-        {
-            "[1 /* ] */]", "[1 // ]\n]", "{\"a\": 1 /* } */ , }", "[1, 2, ]", "[[1,],[2 , /**/ ] , ]",
-            "{\"a\": [] // }\n, \"b\": {} /* } ] */ }", "[ /* empty */ ]", "{ // }\n}", "/* a */ [1] // b",
-            "[\"\\n\" /* \" */ , ]",
-        };
-        for (const auto& text : texts)
-        {
-            CAPTURE(text)
-            CHECK(positions_as_parse<json>(text, true, true));
-        }
-    }
-
-    SECTION("generated documents")
-    {
-        json_view_test::generator gen;
-        for (int i = 0; i < 300; ++i)
-        {
-            std::string text;
-            gen.value(text, 0);
-            CAPTURE(text)
-            CHECK(positions_as_parse<json>(text));
-            CHECK(positions_as_parse<ordered_json>(text));
-        }
-    }
-
-    SECTION("test data")
-    {
-        for (const char* name :
-                {
-                    "/json_testsuite/sample.json", "/nativejson-benchmark/canada.json", "/nativejson-benchmark/citm_catalog.json",
-                    "/nativejson-benchmark/twitter.json", "/json_tests/pass1.json"
-                })
-        {
-            CAPTURE(name)
-            const std::ifstream f(std::string(TEST_DATA_DIRECTORY) + name, std::ios::binary);
-            std::stringstream ss;
-            ss << f.rdbuf();
-            CHECK(positions_as_parse<json>(ss.str()));
-        }
-    }
-
-    SECTION("subtrees")
-    {
-        const std::string text = R"({"a": [1, "\n", {"b": null}], "s": "x\ty", "n": -1.5})";
-        const json j = json::parse(text);
-        const json_document d = json_document::parse(text);
-        CHECK(same_positions(d.root()["a"].materialize(), j["a"]));
-        CHECK(same_positions(d.root()["a"][2].materialize(), j["a"][2]));
-        CHECK(same_positions(d.root()["a"][1].materialize(), j["a"][1]));
-        CHECK(same_positions(d.root()["s"].materialize(), j["s"]));
-        CHECK(same_positions(d.root()["n"].materialize(), j["n"]));
-        CHECK(range(d.root()["a"][1].materialize()) == "10-14");
-        CHECK(range(d.root()["s"].materialize()) == "35-41");
-    }
-
-#if !defined(JSON_NOEXCEPTION)
-    SECTION("exception messages")
-    {
-        const std::string text = "{\n  \"address\": {\"street\": \"Fake\\tStreet\", \"housenumber\": \"1\"},\n  \"list\": [1, [true]]\n}";
-        const json j = json::parse(text);
-        const json_document d = json_document::parse(text);
-        const json m = d.root().materialize();
-        const std::string expected = json_view_test::exception_of_call([&]
-        {
-            static_cast<void>(j.at("address").at("housenumber").get<int>());
-        });
-        CHECK(expected.find("(bytes ") != std::string::npos);
-        CHECK(json_view_test::exception_of_call([&]
-        {
-            static_cast<void>(m.at("address").at("housenumber").get<int>());
-        }) == expected);
-        CHECK(json_view_test::exception_of_call([&]
-        {
-            static_cast<void>(m.at("address").at("street").get<int>());
-        }) == json_view_test::exception_of_call([&]
-        {
-            static_cast<void>(j.at("address").at("street").get<int>());
-        }));
-        CHECK(json_view_test::exception_of_call([&]
-        {
-            static_cast<void>(m.at("list").at(1).get<int>());
-        }) == json_view_test::exception_of_call([&]
-        {
-            static_cast<void>(j.at("list").at(1).get<int>());
-        }));
-    }
-#endif
-
-    SECTION("edited documents")
-    {
-        const std::string text = R"({"a": [1, 2], "b": {"c": "\n", "d": true}, "e": [3, [4]], "f": "x"})";
-        const json j = json::parse(text);
-
-        SECTION("new scalars have none")
-        {
-            json_editable_document d = json_editable_document::parse(text);
-            d.set(d.root()["f"], 5);
-            d.set(d.root()["b"]["d"], "s");
-            const json m = d.root().materialize();
-            CHECK(range(m["f"]) == "none");
-            CHECK(range(m["b"]["d"]) == "none");
-            // the object whose last member is new has none; the others keep theirs
-            CHECK(range(m) == "none");
-            CHECK(range(m["b"]) == "none");
-            CHECK(same_positions(m["a"], j["a"]));
-            CHECK(same_positions(m["e"], j["e"]));
-            CHECK(same_positions(m["b"]["c"], j["b"]["c"]));
-        }
-
-        SECTION("containers whose elements change have none")
-        {
-            json_editable_document d = json_editable_document::parse(text);
-            d.push_back(d.root()["a"], 7);
-            d.erase(d.root()["e"], 0);
-            const json m = d.root().materialize();
-            CHECK(range(m["a"]) == "none");
-            CHECK(range(m["a"][2]) == "none");
-            CHECK(range(m["e"]) == "none");
-            // the elements kept keep theirs
-            CHECK(range(m["a"][0]) == range(j["a"][0]));
-            CHECK(range(m["a"][1]) == range(j["a"][1]));
-            CHECK(same_positions(m["e"][0], j["e"][1]));
-            CHECK(same_positions(m["b"], j["b"]));
-            // the root's elements did not change
-            CHECK(range(m) == range(j));
-        }
-
-        SECTION("new containers have none")
-        {
-            json_editable_document d = json_editable_document::parse(text);
-            d.set(d.root()["b"], json::parse(R"({"x": [1]})"));
-            const json m = d.root().materialize();
-            CHECK(range(m["b"]) == "none");
-            CHECK(range(m["b"]["x"]) == "none");
-            CHECK(range(m["b"]["x"][0]) == "none");
-            CHECK(range(m) == range(j));
-        }
-
-        SECTION("copies of scalars of the document keep theirs")
-        {
-            // (a copy of an array or object is a new one; its scalars are the
-            // parsed ones)
-            json_editable_document d = json_editable_document::parse(text);
-            d.set(d.root()["f"], d.root()["e"]);
-            d.set(d.root()["a"], d.root()["b"]["c"]);
-            const json m = d.root().materialize();
-            CHECK(range(m["a"]) == range(j["b"]["c"]));
-            CHECK(range(m["f"]) == "none");
-            CHECK(range(m["f"][1]) == "none");
-            CHECK(range(m["f"][0]) == range(j["e"][0]));
-            CHECK(range(m["f"][1][0]) == range(j["e"][1][0]));
-        }
-    }
-
-#if !(defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
-    SECTION("images")
-    {
-        const std::string text = R"({"a\n": ["\u00e9", 1.5, {"b": [true, null]}], "c": "d"})";
-        const json j = json::parse(text);
-
-        SECTION("round trip")
-        {
-            const json_document d = json_document::load(json_document::parse(text).save());
-            CHECK(same_positions(d.root().materialize(), j));
-        }
-
-        SECTION("edited")
-        {
-            json_editable_document e = json_editable_document::parse(text);
-            e.set(e.root()["c"], 1);
-            e.push_back(e.root()[std::string("a") + '\n'], false);
-            e.set(e.root()[std::string("a") + '\n'][2]["b"][0], "\"");
-            const json_document d = json_document::load(e.save());
-            const json m = d.root().materialize();
-            CHECK(range(m["c"]) == "none");
-            CHECK(range(m) == "none");
-            const json& a = m[std::string("a") + '\n'];
-            const json& ja = j[std::string("a") + '\n'];
-            CHECK(range(a) == "none");
-            CHECK(range(a[3]) == "none");
-            CHECK(range(a[0]) == range(ja[0]));
-            CHECK(range(a[1]) == range(ja[1]));
-            CHECK(range(a[2]["b"][0]) == "none");
-            CHECK(range(a[2]["b"][1]) == range(ja[2]["b"][1]));
-            // the last element of b is still the parsed one
-            CHECK(range(a[2]["b"]) == range(ja[2]["b"]));
-            CHECK(range(a[2]) == range(ja[2]));
-        }
-
-        SECTION("without positions")
-        {
-            // an image saved without JSON_DIAGNOSTIC_POSITIONS: next is 0 for
-            // the strings with escapes
-            std::vector<std::uint8_t> image = json_document::parse(text).save();
-            std::uint64_t count = 0;
-            std::memcpy(&count, image.data() + 8, sizeof(count));
-            for (std::size_t i = 0; i < count; ++i)
-            {
-                nlohmann::detail::view::node n{};
-                std::memcpy(&n, image.data() + 64 + (i * sizeof(n)), sizeof(n));
-                if (n.kind == nlohmann::detail::view::node_kind::string)
-                {
-                    n.next = 0;
-                }
-                std::memcpy(image.data() + 64 + (i * sizeof(n)), &n, sizeof(n));
-            }
-            const json_document d = json_document::load(image);
-            const json m = d.root().materialize();
-            CHECK(range(m[std::string("a") + '\n'][0]) == "none");
-            CHECK(range(m["c"]) == range(j["c"]));
-            CHECK(same_positions(m[std::string("a") + '\n'][2], j[std::string("a") + '\n'][2]));
-        }
-
-#if !defined(JSON_NOEXCEPTION)
-        SECTION("a decoded string's position must be within the text")
-        {
-            std::vector<std::uint8_t> image = json_document::parse(R"(["\n"])").save();
-            nlohmann::detail::view::node n{};
-            std::memcpy(&n, image.data() + 64 + sizeof(n), sizeof(n));
-            REQUIRE(n.next == 2);
-            n.next = 7;
-            std::memcpy(image.data() + 64 + sizeof(n), &n, sizeof(n));
-            CHECK_THROWS_AS(json_document::load(image), json::parse_error&);
-            // without the check, the position is out of bounds and ignored
-            const json_document d = json_document::load(image, json_document::image_check::none);
-            CHECK(range(d.root()[0].materialize()) == "none");
-        }
-#endif
-    }
-#endif
-}
Author	SHA1	Message	Date
Niels Lohmann	ff1025c4e4	Merge develop Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-27 14:31:51 +01:00
Niels Lohmann	51abba08fd	Merge branch 'develop' into claude/json-view-canada-perf-99bbe3 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-27 07:29:22 +01:00
Niels Lohmann	e08c181dee	Merge origin/develop into claude/json-view-canada-perf-99bbe3 The float-pair fast path of the serializer compares node_kind now. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-26 21:41:12 +01:00
Niels Lohmann	c227d4a920	Remove unused using-declaration in unit-json_view_large Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-26 15:53:28 +01:00
Niels Lohmann	bdcfc178af	Fix clang-tidy findings in the json_view dump tests Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-26 06:54:53 +01:00
Niels Lohmann	30e1adef93	Merge develop; fix clang-tidy, cpplint and clang 3.5 findings in json_view Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-25 19:03:03 +01:00
Niels Lohmann	afea570755	json_view: fix GCC useless-cast, MSVC C4127, and MinGW object size - drop the redundant int cast of the promoted uint16_t shift (-Wuseless-cast) - route the constant part of the float-pair condition through enabled() (C4127) - split unit-json_view_dump.cpp in three files for the MinGW assembler Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-25 10:45:57 +01:00
Niels Lohmann	e7d245db7e	json_view: dump canada.json faster than yyjson (batched float decisions) Dump of float tokens of 16 or 17 digits without an exponent (SIMD targets, little-endian), in batches of up to 256 floats ahead of the walk, one loop per step: - the digits (16 bytes at a time) and the token's last four digits; - locate_token(): Eisel-Lemire's product gives the double x, and x's position relative to the token is exact in a 64-bit fixed-point number (56 bits after the point of the token's last digit), with the radius of its interval; - token_digits_1/2(), one loop per kind (g): the multiple of 10^g nearest to x if it is in the interval, else the multiple of 10^(g - 1) nearest to x, the digits that dump() (Zmij) writes. Exact ties between two candidates (like 754570942.33984373, whose double is ...33984375) are left to the full conversion; - the output is the token with its last four digits replaced; a rounding that carries further goes to the writer of Zmij's results. The batch storage is on the heap (allocated by the first conversion), and a pair of floats like [x, y] in a read-only document is written without a frame. Reading: get<double>() converts such tokens with a lean Eisel-Lemire (coordinate_float()). Output is byte-identical to the previous writer: 10^9 generated tokens in one array and 3 * 10^8 in arrays of 1 to 9 elements on Apple M1, 2.5 * 10^8 and 10^8 on x86-64 (all exponents, subnormals, 15-18 digits, exact binary fractions and ties, near-short decimals); get<double>() equals json::parse on 5 * 10^7 values. compare.py --download, Apple M1 Max, clang 21, 30 rounds, two runs (and two with aligned code: -falign-loops=64 -mllvm -align-all-functions=6); json_view, and the factor of yyjson 0.13.0 over it: - canada dump 3636 -> 1623 us (0.47x -> 1.06x; aligned 1.05x) - canada traverse 2287 -> 1817 us (0.85x -> 1.07x; aligned 0.99x) - canada patch 4628 -> 2735 us (0.80x -> 1.36x) - canada update 4763 -> 2911 us (0.78x -> 1.28x) Linux x86-64 (Haswell VPS, GCC 13, one run): canada dump 0.53x -> 0.72x, traverse 0.89x -> 0.95x, patch 1.01x -> 1.17x, update 0.96x -> 1.13x. Open: canada traverse in the aligned build (0.99x) and canada dump on x86-64 (0.72x) are still behind yyjson. Canada parse and select are about 2 % slower in bench_view in both builds, with identical parser code (likely layout; the corpus parse row is not slower). In the plain build only, rpc, status, and twitter dump are 2-4 % slower (0-6 % faster in the aligned build). Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-25 07:23:43 +01:00
Niels Lohmann	d38a04bd3e	json_view: faster float tokens of 16 to 19 digits (canada dump, traverse) Reading: - layout_decimal() reads tokens of 16 to 19 digits 16 bytes at a time (NEON / SSE2) and layout_float() sends them to Eisel-Lemire directly, without the fast-path check that mixed data mispredicts. Dump (AArch64 only): - Fixed-notation tokens of 16 or 17 digits are converted in batches ahead of the walk, one loop per step: digits, Eisel-Lemire, and an exact 8.56 fixed-point choice of the shortest digits (shortest_token_digits(), in place of Zmij for these tokens). The output is the token with its last eight digits replaced. On x86-64 (Haswell, GCC 13 / Clang 18) the batch was not faster, so it is not used there. - Output is byte-identical to the previous writer: 10^9 generated tokens on M1 (all exponents, subnormals, 15-18 digits, exact binary fractions, near-short decimals) and 2.5 * 10^8 on x86-64, plus canada, twitter and citm_catalog in compact, indented, and ensure_ascii form. compare.py --download, M1 Max, clang 21, 30 rounds, two runs and aligned builds; json_view, and the factor of yyjson 0.13.0 over it: - canada dump 3636 -> 2597 us (0.47x -> 0.66x) - canada traverse 2300 -> 2059 us (0.85x -> 0.96x) - canada patch 4650 -> 3550 us (0.80x -> 1.05x) - canada update 4882 -> 3813 us (0.78x -> 1.00x) Linux x86-64 (umbrella, GCC 13): canada traverse 0.89x -> 0.95x, patch 0.98x -> 1.02x, update 0.96x -> 1.01x, dump 0.53x -> 0.57x. Open: the dump and traverse targets (>= 1.0x) are missed. The dump is bounded by the shortest-digits step (~8 ns per float, one multiply chain per float). Three rows are more than 1 % slower than before in both the plain and the aligned build, without a known cause (the parser's machine code is identical, and these documents do not use the new float path): - edit status patch +2.7 % (aligned +1.9 %) - edit citm_catalog update +1.7 % (aligned +1.5 %) - view jeopardy select +1.4 % (aligned +1.0 %) Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-10-25 07:23:42 +01:00