Dispatch on the compile-time conditions of the json_view comparison

MSVC (/W4 /WX) reported C4127 (conditional expression is constant) for
the template parameter EA and the object type's ordering in an if
condition; both are now tag-dispatched.

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

docs/mkdocs/docs/api/basic_json/accept.md

@@ -23,9 +23,6 @@ Checks whether the input is valid JSON.
     respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
     the iterator type with `operator!=`.
     
-    Ill-formed UTF-16 and UTF-32 sequences are rejected: a lone surrogate, a high surrogate that is not followed by its
-    low surrogate, and a code point above `U+10FFFF` all make this function return `false`.
-
 Unlike the [`parse()`](parse.md) function, this function neither throws an exception in case of invalid JSON input
 (i.e., a parse error) nor creates diagnostic information.
 
@@ -38,12 +35,9 @@ Unlike the [`parse()`](parse.md) function, this function neither throws an excep
     - a `#!c FILE` pointer (throws if null)
     - a C-style array of characters
     - a pointer to a null-terminated string of single byte characters (throws if null)
-    - a `std::string` or a `std::string_view` (C++17)
+    - a `std::string`
     - a container `obj` for which `begin(obj)` and `end(obj)` produce a valid pair of iterators
       (as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
-    - wide characters (`wchar_t`, `char16_t`, `char32_t`), which are converted to UTF-8: a wide string object
-      (`std::wstring`, `std::u16string`, `std::u32string`) or an array (e.g. a wide string literal); a pointer to a
-      null-terminated wide string (e.g. `std::u16string::c_str()`) is not supported
 
 `IteratorType`
 :   a compatible iterator type, for instance.
@@ -131,21 +125,6 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
     --8<-- "examples/accept__iterator_pair.output"
     ```
 
-??? example "Example: (3) reading from UTF-16 strings"
-
-    The encoding is deduced from the character type of the input. String literals like `u"..."`, `U"..."`, and
-    `L"..."` work as well.
-
-    ```cpp
-    --8<-- "examples/accept__wide_string.cpp"
-    ```
-
-    Output:
-
-    ```json
-    --8<-- "examples/accept__wide_string.output"
-    ```
-
 ## See also
 
 - [parse](parse.md) - deserialize from a compatible input
@@ -172,9 +151,6 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
   ([`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md)).
 - Parsing from a `FILE*` locks the file once instead of once per character in version 3.13.0
   ([`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md)).
-- Ill-formed UTF-16 and UTF-32 input (a lone surrogate, a high surrogate that is not followed by its low surrogate, or
-  a code point above `U+10FFFF`) is rejected in version 3.13.0; before that, some such sequences were accepted or
-  ended the input silently.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/index.md

@@ -44,22 +44,6 @@ are collected in [Template Parameter Requirements](../../features/types/template
 - [**json**](../json.md) - default specialization
 - [**ordered_json**](../ordered_json.md) - a specialization that maintains the insertion order of object keys
 
-## Documents and views
-
-Besides `basic_json`, the library offers a second way to hold a parsed JSON text: a
-[`basic_json_document`](../basic_json_document/index.md), which owns or borrows the text and holds a flat index of the
-values in it, and a [`basic_json_view`](../basic_json_view/index.md), a read-only handle to one value of such a document.
-Both are defined in the header `<nlohmann/json_view.hpp>`; see
-[Zero-copy JSON views](../../features/json_view.md) for the concept and the trade-offs.
-
-- [**json_document**](../json_document.md) / [**ordered_json_document**](../ordered_json_document.md) - read-only
-  documents of the `basic_json` specialization they belong to
-- [**json_editable_document**](../json_editable_document.md) /
-  [**ordered_json_editable_document**](../ordered_json_editable_document.md) - documents that can be modified in place
-- [**json_view**](../json_view.md) / [**ordered_json_view**](../ordered_json_view.md) - views of a document
-- [**json_editable_view**](../json_editable_view.md) /
-  [**ordered_json_editable_view**](../ordered_json_editable_view.md) - views of an editable document
-
 ## Iterator invalidation
 
 All operations that add values to an **array** ([`push_back`](push_back.md) , [`operator+=`](operator+=.md),
@@ -359,9 +343,6 @@ Access to the JSON value
 ## See also
 
 - [RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format](https://tools.ietf.org/html/rfc8259)
-- [basic_json_document](../basic_json_document/index.md) / [basic_json_view](../basic_json_view/index.md) - parse a JSON
-  text into a flat index and read it through a view
-- [Zero-copy JSON views](../../features/json_view.md) - when to use a document and a view instead of a `basic_json`
 
 ## Version history
 

docs/mkdocs/docs/api/basic_json/parse.md

@@ -25,10 +25,6 @@ static basic_json parse(IteratorType first, SentinelType last,
     respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
     the iterator type with `operator!=`.
 
-    Ill-formed UTF-16 and UTF-32 sequences are rejected: a lone surrogate, a high surrogate that is not followed by its
-    low surrogate, and a code point above `U+10FFFF` all yield a
-    [`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101).
-
 ## Template parameters
 
 `InputType`
@@ -38,12 +34,9 @@ static basic_json parse(IteratorType first, SentinelType last,
     - a `FILE` pointer (throws if null)
     - a C-style array of characters
     - a pointer to a null-terminated string of single byte characters (throws if null)
-    - a `std::string` or a `std::string_view` (C++17)
+    - a `std::string`
     - a container `obj` for which `begin(obj)` and `end(obj)` produce a valid pair of iterators
       (as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
-    - wide characters (`wchar_t`, `char16_t`, `char32_t`), which are converted to UTF-8: a wide string object
-      (`std::wstring`, `std::u16string`, `std::u32string`) or an array (e.g. a wide string literal); a pointer to a
-      null-terminated wide string (e.g. `std::u16string::c_str()`) is not supported
 
 `IteratorType`
 :   a compatible iterator type, for instance.
@@ -119,13 +112,6 @@ By default, a `'\0'` (NUL) byte anywhere in the input is treated as end of input
 outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-bytes-in-the-input) for details and the
 [`JSON_STRICT_NUL_HANDLING`](../macros/json_strict_nul_handling.md) macro to opt into rejecting it instead.
 
-!!! tip "Parsing into a document instead of a value"
-
-    [`basic_json_document::parse`](../basic_json_document/parse.md) accepts the same inputs and the same options, but
-    keeps the result as a flat index of the parsed values instead of a tree of `basic_json` values. It is faster and uses
-    less memory when only parts of the document are read, and it also accepts a pointer to a null-terminated wide string,
-    which `parse()` does not. See [Zero-copy JSON views](../../features/json_view.md).
-
 !!! tip "Performance"
 
     Contiguous inputs (strings, string views, vectors, arrays, pointer ranges) are the fastest to parse. A
@@ -264,22 +250,6 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
     --8<-- "examples/trailing_commas.output"
     ```
 
-??? example "Example: parse from UTF-16, UTF-32, and wide strings"
-
-    The encoding is deduced from the character type of the input; `std::u16string` and `std::u32string` are interpreted
-    as UTF-16 and UTF-32, and `std::wstring` uses the platform's `wchar_t` width. String literals like `u"..."`,
-    `U"..."`, and `L"..."` work as well, as do iterators over wide characters.
-
-    ```cpp
-    --8<-- "examples/parse__wide_string.cpp"
-    ```
-
-    Output:
-
-    ```json
-    --8<-- "examples/parse__wide_string.output"
-    ```
-
 ## See also
 
 - [accept](accept.md) - check if the input is valid JSON
@@ -310,9 +280,6 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
   time).
 - Parsing from a `FILE*` locks the file once instead of once per character in version 3.13.0
   ([`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md) restores `std::fgetc`).
-- Ill-formed UTF-16 and UTF-32 input (a lone surrogate, a high surrogate that is not followed by its low surrogate, or
-  a code point above `U+10FFFF`) is rejected with `parse_error.101` in version 3.13.0; before that, some such
-  sequences were accepted or ended the input silently.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/sax_parse.md

@@ -31,10 +31,6 @@ Read from input and generate SAX events
     respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
     the iterator type with `operator!=`.
 
-    Ill-formed UTF-16 and UTF-32 sequences are rejected: a lone surrogate, a high surrogate that is not followed by its
-    low surrogate, and a code point above `U+10FFFF` all yield a
-    [`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101).
-
 The SAX event lister must follow the interface of [`json_sax`](../json_sax/index.md).
 
 ## Template parameters
@@ -46,12 +42,8 @@ The SAX event lister must follow the interface of [`json_sax`](../json_sax/index
     - a `FILE` pointer
     - a C-style array of characters
     - a pointer to a null-terminated string of single byte characters
-    - a `std::string` or a `std::string_view` (C++17)
     - a container `obj` for which `begin(obj)` and `end(obj)` produce a valid pair of iterators
       (as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
-    - wide characters (`wchar_t`, `char16_t`, `char32_t`), which are converted to UTF-8: a wide string object
-      (`std::wstring`, `std::u16string`, `std::u32string`) or an array (e.g. a wide string literal); a pointer to a
-      null-terminated wide string (e.g. `std::u16string::c_str()`) is not supported
 
 `IteratorType`
 :   a compatible iterator type for overload (2); a pair of character iterators whose `value_type` is an integral type
@@ -168,9 +160,6 @@ use the same file with stdio functions, but it must not wait for another thread
   ([`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md)).
 - Parsing from a `FILE*` locks the file once instead of once per character in version 3.13.0
   ([`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md)).
-- Ill-formed UTF-16 and UTF-32 input (a lone surrogate, a high surrogate that is not followed by its low surrogate, or
-  a code point above `U+10FFFF`) is rejected with `parse_error.101` in version 3.13.0; before that, some such
-  sequences were accepted or ended the input silently.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json_document/index.md

@@ -115,12 +115,6 @@ points apply to every edit:
   [`source_offset()`](../basic_json_view/source_offset.md) of a value introduced by an edit is
   `#!cpp static_cast<std::size_t>(-1)`, the same value it reports for a decoded string.
 
-## See also
-
-- [basic_json_view](../basic_json_view/index.md) - the read-only handle to a value of a document
-- [json_document](../json_document.md) - this template for the default specialization `nlohmann::json`
-- [Zero-copy JSON views](../../features/json_view.md) - the concept behind documents and views
-
 ## Version history
 
 - Added in version 3.13.0.

docs/mkdocs/docs/api/basic_json_document/parse.md

@@ -21,19 +21,17 @@ static basic_json_document parse(IteratorType first, IteratorType last,
 
 Both overloads accept the same JSON text as [`BasicJsonType::parse()`](../basic_json/parse.md), with the same
 `ignore_comments`/`ignore_trailing_commas` options, but build a [`basic_json_document`](index.md) (a flat index into
-the input) instead of a tree of `BasicJsonType` values. They take every input `BasicJsonType::parse()` takes, and in
+the input) instead of a tree of `BasicJsonType` values. They take the same inputs as `BasicJsonType::parse()`. Byte
-addition a pointer to a null-terminated wide string (which `BasicJsonType::parse()` rejects). Contiguous inputs of
+inputs that stay alive can be borrowed; all others (streams, `#!cpp FILE*`, wide characters, non-contiguous
-single-byte characters that stay alive can be borrowed; all others (streams, `#!cpp FILE*`, wide characters, which
+iterators) are read into a copy that the document owns -- see the Notes. Use [`parse_copy()`](parse_copy.md) to get an
-must be converted to UTF-8, and non-contiguous iterators) are read into a copy that the document owns -- see the
+owned copy of a borrowable input as well.
-Notes. Use [`parse_copy()`](parse_copy.md) to get an owned copy of a borrowable input
-as well.
 
 ## Template parameters
 
 `InputType`
 :   A compatible input, for instance:
 
-    - a `#!cpp std::string`, a `#!cpp std::string_view` (C++17), or a C-style array of single-byte characters
+    - a `#!cpp std::string`, `#!cpp std::string_view`, or a C-style array of single-byte characters
     - a pointer to a null-terminated string of single-byte characters (`#!cpp char`, `#!cpp signed char`,
       `#!cpp unsigned char`, `#!cpp std::uint8_t`)
     - a container for which `#!cpp obj.data()` and `#!cpp obj.size()` give contiguous single-byte access, e.g.
@@ -49,10 +47,6 @@ as well.
     `#!cpp std::string::iterator`; the iterators of single-byte characters are borrowed or read like the byte inputs
     above, those of wide characters are converted to UTF-8
 
-Ill-formed UTF-16 and UTF-32 sequences are rejected: a lone surrogate, a high surrogate that is not followed by its low
-surrogate, and a code point above `U+10FFFF` all yield a
-[`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101).
-
 ## Parameters
 
 `input` (in)
@@ -161,5 +155,3 @@ buffer of a given length, pass a pair of pointers: `#!cpp parse(ptr, ptr + len)`
 ## Version history
 
 - Added in version 3.13.0.
-- Ill-formed UTF-16 and UTF-32 input (a lone surrogate, a high surrogate that is not followed by its low surrogate, or
-  a code point above `U+10FFFF`) is rejected with `parse_error.101`.

docs/mkdocs/docs/api/basic_json_view/index.md

@@ -143,12 +143,6 @@ still refers to it -- including ones taken before the change -- reads the new va
 
 - [**source_offset**](source_offset.md) - byte offset of this value in the document's source text
 
-## See also
-
-- [basic_json_document](../basic_json_document/index.md) - the document a view refers into
-- [materialize](materialize.md) - build the `BasicJsonType` value of a subtree
-- [Zero-copy JSON views](../../features/json_view.md) - the concept behind documents and views
-
 ## Version history
 
 - Added in version 3.13.0.

docs/mkdocs/docs/examples/accept__wide_string.cpp

@@ -1,18 +0,0 @@
-#include <iostream>
-#include <string>
-#include <nlohmann/json.hpp>
-
-using json = nlohmann::json;
-
-int main()
-{
-    // a valid JSON text, given as UTF-16
-    const std::u16string valid_text = u"{\"name\":\"\u00e9\"}";
-
-    // an invalid JSON text, given as UTF-16
-    const std::u16string invalid_text = u"{\"name\":\"\u00e9\",}";
-
-    std::cout << std::boolalpha
-              << json::accept(valid_text) << ' '
-              << json::accept(invalid_text) << '\n';
-}

docs/mkdocs/docs/examples/accept__wide_string.output

@@ -1 +0,0 @@
-true false

docs/mkdocs/docs/examples/parse__wide_string.cpp

@@ -1,27 +0,0 @@
-#include <iostream>
-#include <string>
-#include <nlohmann/json.hpp>
-
-using json = nlohmann::json;
-
-int main()
-{
-    // the same JSON text, given in different encodings
-    const std::string utf8 = "{\"name\":\"\u00e9\"}";
-    const std::u16string utf16 = u"{\"name\":\"\u00e9\"}";
-    const std::u32string utf32 = U"{\"name\":\"\u00e9\"}";
-    const std::wstring wide = L"{\"name\":\"\u00e9\"}";
-
-    // the encoding is deduced from the character type of the input, and all
-    // of them yield the same value
-    std::cout << json::parse(utf8) << '\n'
-              << json::parse(utf16) << '\n'
-              << json::parse(utf32) << '\n'
-              << json::parse(wide) << '\n';
-
-    // a wide string literal works as well: u"..." is UTF-16, U"..." is UTF-32
-    std::cout << json::parse(u"[1, 2, 3]") << '\n';
-
-    // iterators over wide characters work as well
-    std::cout << json::parse(utf16.begin(), utf16.end()) << '\n';
-}

docs/mkdocs/docs/examples/parse__wide_string.output

@@ -1,6 +0,0 @@
-{"name":"é"}
-{"name":"é"}
-{"name":"é"}
-{"name":"é"}
-[1,2,3]
-{"name":"é"}

docs/mkdocs/docs/features/conversions.md

@@ -38,18 +38,6 @@ which avoids repeating it:
     --8<-- "examples/get_to.output"
     ```
 
-!!! info "Getting values out of a document or a view"
-
-    A [view](../api/basic_json_view/index.md) offers the same `get<T>()` conversion. For the built-in types (booleans,
-    numbers, strings, `#!cpp std::vector`, `#!cpp std::map`, ...) it reads the value straight from the document's
-    index, without building a `basic_json` value first; user-defined types with a `from_json()` are converted from a
-    `basic_json` value, see the [list](../api/basic_json_view/get.md). Two conversions never copy at all:
-    [`get_string()`](../api/basic_json_view/get_string.md) returns a string as a view into the source text, and
-    [`number_token()`](../api/basic_json_view/number_token.md) returns a number exactly as it was written. Every other
-    type is obtained from a subtree that is built on demand with
-    [`materialize()`](../api/basic_json_view/materialize.md). See
-    [Zero-copy JSON views](json_view.md#getting-values-out-without-copying).
-
 The library already knows how to convert to and from the scalar types and the STL containers (such as
 `#!cpp std::vector`, `#!cpp std::map`, `#!cpp std::array`, `#!cpp std::optional`, and many more). Converting a JSON
 object back to a `#!cpp std::map` or a JSON array back to a `#!cpp std::vector` therefore works without any extra code:
@@ -246,4 +234,3 @@ The conversions above are built in for standard types. To make the same syntax w
 - [`get_ref`](../api/basic_json/get_ref.md) / [`get_ptr`](../api/basic_json/get_ptr.md) - access the stored value without copying
 - [Arbitrary types conversions](arbitrary_types.md) - support your own types
 - [`JSON_USE_IMPLICIT_CONVERSIONS`](../api/macros/json_use_implicit_conversions.md) - toggle implicit conversions
-- [Zero-copy JSON views](json_view.md) - get values out of a document or a view

docs/mkdocs/docs/features/creating_values.md

@@ -1,9 +1,7 @@
 # Creating JSON values
 
 There are several ways to create a JSON value in memory. This page gives an overview; to read a value from JSON text
-instead, see [parsing](parsing/index.md). A JSON text can also be parsed into a
+instead, see [parsing](parsing/index.md).
-[document](../api/basic_json_document/index.md) and read through a [view](../api/basic_json_view/index.md) instead of
-into a value; see [Zero-copy JSON views](json_view.md).
 
 ## From C++ values
 
@@ -103,4 +101,3 @@ string `#!json "42"`.
 - [`operator""_json`](../api/operator_literal_json.md) - the `_json` literal
 - [Converting values](conversions.md) - which C++ types can be used
 - [Parsing](parsing/index.md) - create a value from JSON text
-- [Zero-copy JSON views](json_view.md) - create a document and a view from JSON text instead of a value

docs/mkdocs/docs/features/macros.md

@@ -287,23 +287,6 @@ external dependency and is not defined by default.
 
 See [full documentation of `JSON_USE_SIMDUTF`](../api/macros/json_use_simdutf.md).
 
-## `JSON_VIEW_NO_SIMD`
-
-When defined, the parser of [`basic_json_document`](../api/basic_json_document/index.md)
-(`<nlohmann/json_view.hpp>`) uses only portable C++ to scan strings, instead of vector instructions (SSE2 on x86-64,
-NEON on AArch64). The same input is accepted or rejected either way; only the speed differs. It is not defined by
-default.
-
-See [full documentation of `JSON_VIEW_NO_SIMD`](../api/macros/json_view_no_simd.md).
-
-## `JSON_VIEW_USE_SSSE3`
-
-When defined on x86-64, the parser of [`basic_json_document`](../api/basic_json_document/index.md)
-(`<nlohmann/json_view.hpp>`) validates non-ASCII text in strings with SSSE3 without asking the CPU first. It is not
-defined by default.
-
-See [full documentation of `JSON_VIEW_USE_SSSE3`](../api/macros/json_view_use_ssse3.md).
-
 ## `NLOHMANN_DEFINE_TYPE_*(...)`, `NLOHMANN_DEFINE_DERIVED_TYPE_*(...)`
 
 The library defines 12 macros to simplify the serialization/deserialization of types. See the page on

docs/mkdocs/docs/features/modifying_values.md

@@ -85,18 +85,6 @@ json a = {1, 2, 3, 4};
 a.erase(1);             // [1,3,4]  (erase by index)
 ```
 
-## Editing a document
-
-The operations above work on a `basic_json` value. A JSON text that was parsed into a
-[document](json_view.md#editing-a-document) can also be changed in place, without building a `basic_json` tree for the
-parts that are not touched: [`set`](../api/basic_json_document/set.md) replaces a value, adds or replaces an object
-member, or replaces an array element (also through a JSON pointer),
-[`push_back`](../api/basic_json_document/push_back.md) appends to an array,
-[`insert`](../api/basic_json_document/insert.md) inserts into an array (unlike `basic_json::insert`, it has no object
-overload; members are added with `set`), and [`erase`](../api/basic_json_document/erase.md) removes a member or an
-element. These functions are available on the
-editable document types, such as [`json_editable_document`](../api/json_editable_document.md).
-
 ## See also
 
 - [`push_back`](../api/basic_json/push_back.md) / [`emplace_back`](../api/basic_json/emplace_back.md) - append to an array
@@ -105,4 +93,3 @@ editable document types, such as [`json_editable_document`](../api/json_editable
 - [`merge_patch`](../api/basic_json/merge_patch.md) - apply an RFC 7396 merge patch
 - [`erase`](../api/basic_json/erase.md) / [`clear`](../api/basic_json/clear.md) - remove elements
 - [JSON Patch and Diff](json_patch.md) and [JSON Merge Patch](merge_patch.md) - structured modifications
-- [Editing a document](json_view.md#editing-a-document) - change a parsed document in place

docs/mkdocs/docs/features/parsing/index.md

@@ -18,7 +18,6 @@ flowchart LR
 The [`parse`](../../api/basic_json/parse.md) function reads a JSON value from an input. The input can be
 
 - a string (`#!cpp std::string`, C string, or string literal),
-- a wide string (`#!cpp std::u16string`, `#!cpp std::u32string`, or `#!cpp std::wstring`, or a wide string literal),
 - a `#!cpp std::istream` (e.g., an `#!cpp std::ifstream` reading from a file),
 - a `#!cpp FILE*` pointer,
 - a pair of iterators over a contiguous range (e.g., a `#!cpp std::vector<std::uint8_t>`), or
@@ -33,18 +32,12 @@ std::ifstream f("example.json");
 json data = json::parse(f);
 ```
 
-The input must be encoded in UTF-8; other encodings are not supported. The exception is wide-character input, which
+The input must be encoded in UTF-8; other encodings are not supported. A single input may contain only one JSON value.
-is read as UTF-16 or UTF-32 -- depending on the character type -- and converted to UTF-8; see the
-[`parse`](../../api/basic_json/parse.md) page for an example. A single input may contain only one JSON value.
 Inputs consisting of multiple values separated by newlines are handled by the [JSON Lines](json_lines.md) format.
 
 By default, the library rejects comments and trailing commas. Both can be enabled with parameters of the `parse`
 function — see [comments](../comments.md) and [trailing commas](../trailing_commas.md).
 
-[`basic_json_document::parse`](../../api/basic_json_document/parse.md) accepts the same inputs with the same options,
-but keeps the result in a document rather than in a `basic_json` value; see
-[Documents and views](#documents-and-views) below.
-
 ## Strictness and trailing data
 
 [`parse`](../../api/basic_json/parse.md) reads a single JSON value and requires the whole input to be consumed: any
@@ -105,26 +98,6 @@ The library offers two parsing models:
 You can influence a DOM parse without switching to the SAX interface by passing a
 [parser callback](parser_callbacks.md), which is called during parsing and can, for example, discard parts of the input.
 
-## Documents and views
-
-A third model sits between DOM and SAX: [`basic_json_document::parse`](../../api/basic_json_document/parse.md) parses
-the input into a document that keeps the text and a flat index of the values in it, and
-[`basic_json_view`](../../api/basic_json_view/index.md) gives read-only access to the values through that index.
-The whole input is validated during parsing, but only strings that contain escape sequences are decoded right away
-(into a buffer owned by the document). Numbers and all other strings stay in the source text and are only converted
-when they are read, which is faster and uses less memory than building a tree of `basic_json` values when only parts
-of the document are needed. A document can also be
-modified in place, and it can be saved and loaded again without parsing it.
-
-```cpp
-#include <nlohmann/json_view.hpp>
-
-json_document doc = json_document::parse(R"({"happy": true, "pi": 3.141})");
-std::cout << doc.root()["happy"].get<bool>() << '\n';
-```
-
-See [Zero-copy JSON views](../json_view.md) for the concept and the trade-offs.
-
 ## Exceptions
 
 When the input is not valid JSON, the `parse` function throws an exception by default. If exceptions are undesired or
@@ -135,7 +108,6 @@ options.
 ## See also
 
 - [`parse`](../../api/basic_json/parse.md) - deserialize from a compatible input
-- [`basic_json_document::parse`](../../api/basic_json_document/parse.md) - deserialize into a document instead of a value
 - [`accept`](../../api/basic_json/accept.md) - check if the input is valid JSON
 - [`sax_parse`](../../api/basic_json/sax_parse.md) - generate SAX events
 - [JSON Lines](json_lines.md) - parse newline-delimited JSON
@@ -143,4 +115,3 @@ options.
 - [SAX interface](sax_interface.md) - implement a custom SAX handler
 - [parsing and exceptions](parse_exceptions.md) - control error handling
 - [parsing untrusted input](untrusted_input.md) - what to consider when parsing input from untrusted sources
-- [Zero-copy JSON views](../json_view.md) - parse into a document and read it through a view

docs/mkdocs/docs/features/parsing/untrusted_input.md

@@ -81,9 +81,6 @@ Invalid UTF-8 is rejected while parsing, not just while serializing:
 
 - In JSON text, an ill-formed UTF-8 byte in a string is a
   [`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101) ("invalid string: ill-formed UTF-8 byte").
-- In UTF-16 or UTF-32 input, an ill-formed sequence is a
-  [`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101) as well: a lone surrogate, a high surrogate
-  that is not followed by its low surrogate, and a code point above `U+10FFFF` are all rejected.
 - In a binary format, a string that is not valid UTF-8 is a
   [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113).
 

docs/mkdocs/docs/home/debugging.md

@@ -1,7 +1,7 @@
 # Debugging
 
-This page collects the library's built-in debugger integrations and other debugging-related features. They are not
+This page collects the library's built-in debugger integrations and other debugging-related features. They are
-covered by any single page elsewhere in the docs, so they are collected here.
+not linked from a single place elsewhere in the docs, so are collected here.
 
 ## Visual Studio (natvis)
 

docs/mkdocs/docs/home/exceptions.md

@@ -99,8 +99,7 @@ As this global context comes at the price of storing one additional pointer per
 
     Now the exception message contains a JSON Pointer `/address/housenumber` that indicates which value has the wrong type.
 
-See [documentation of `JSON_DIAGNOSTICS`](../api/macros/json_diagnostics.md) for more information, and
+See [documentation of `JSON_DIAGNOSTICS`](../api/macros/json_diagnostics.md) for more information.
-[Debugging](debugging.md) for the debugger integrations of the library.
 
 ## Parse errors
 

docs/mkdocs/docs/home/faq.md

@@ -81,9 +81,8 @@ rejected by default, and the library never adds them when serializing.
 
 The library supports **Unicode input** as follows:
 
-- **UTF-8** encoded input is supported, which is the default encoding for JSON, according to [RFC 8259](https://tools.ietf.org/html/rfc8259.html#section-8.1).
+- Only **UTF-8** encoded input is supported, which is the default encoding for JSON, according to [RFC 8259](https://tools.ietf.org/html/rfc8259.html#section-8.1).
-- `std::u16string` and `std::u32string` can be parsed, assuming UTF-16 and UTF-32 encoding, respectively; `std::wstring` works as well and is interpreted as UTF-16 or UTF-32, depending on the width of the platform's `wchar_t`. These encodings cannot be read from a `FILE*` or a `std::istream`, which carry bytes only.
+- `std::u16string` and `std::u32string` can be parsed, assuming UTF-16 and UTF-32 encoding, respectively. These encodings are not supported when reading from files or other input containers.
-- Ill-formed UTF-16 or UTF-32 input is rejected: a lone surrogate, a high surrogate that is not followed by its low surrogate, and a code point above `U+10FFFF` all yield a parse error. The same holds for iterators over 2- or 4-byte characters.
 - Other encodings such as Latin-1 or ISO 8859-1 are **not** supported and will yield parse or serialization errors.
 - The library will not replace [Unicode noncharacters](http://www.unicode.org/faq/private_use.html#nonchar1).
 - Invalid surrogates (e.g., incomplete pairs such as `\uDEAD`) will yield parse errors.
@@ -147,7 +146,7 @@ json::parse(std::string("\"") + '\0' + "\""); // throws parse_error.101: control
 
     Why are wide strings (e.g., `std::wstring`) dumped as arrays of numbers?
 
-As described [above](#parse-errors-reading-non-ascii-characters), the library stores its strings as UTF-8. To store a wide string as a string, convert it to a UTF-8 encoded `std::string` first, as in the example below.
+As described [above](#parse-errors-reading-non-ascii-characters), the library assumes UTF-8 as encoding.  To store a wide string, you need to change the encoding.
 
 !!! example
 

docs/mkdocs/docs/index.md

@@ -6,9 +6,7 @@ JSON for Modern C++ is a header-only C++11 library that turns JSON into a first-
 magic of modern C++ so that creating, reading, and modifying JSON values feels as natural as it does in languages like
 Python. The whole library is available as a single header, `json.hpp`, with no dependencies, no subproject, and no
 complex build system to set up; a companion header, `json_fwd.hpp`, provides forward declarations to keep compile times
-down, `<nlohmann/json_literals.hpp>` holds the user-defined string literals on their own, and
+down. See [header-only integration](integration/index.md) for details. It is heavily unit-tested with 100% code
-`<nlohmann/json_view.hpp>` adds zero-copy views and editable documents. See
-[header-only integration](integration/index.md) for details. It is heavily unit-tested with 100% code
 coverage, checked with Valgrind and the Clang Sanitizers for memory leaks, and continuously fuzz-tested by Google
 OSS-Fuzz.
 
@@ -60,8 +58,7 @@ Conda, and more), and pkg-config.
 
     ---
 
-    Creating, parsing, accessing, and serializing JSON values, JSON Pointer/Patch, binary formats, zero-copy views,
+    Creating, parsing, accessing, and serializing JSON values, JSON Pointer/Patch, binary formats, and more.
-    and more.
 
     [:octicons-arrow-right-24: Features](features/index.md)
 
@@ -77,8 +74,7 @@ Conda, and more), and pkg-config.
 
     ---
 
-    The complete reference for `basic_json` and its member functions, types, and related classes, as well as for
+    The complete reference for `basic_json` and its member functions, types, and related classes.
-    `json_document` and `json_view`.
 
     [:octicons-arrow-right-24: API documentation](api/basic_json/index.md)
 

include/nlohmann/detail/view/image.hpp

@@ -255,6 +255,81 @@ struct number_token
     bool is_float; ///< a fraction or an exponent
 };
 
+/// advance over ASCII digits, eight bytes at a time
+inline const unsigned char* digit_run(const unsigned char* p, const unsigned char* e) noexcept
+{
+    constexpr std::uint64_t ones = 0x0101010101010101ull;
+    while (e - p >= 8)
+    {
+        // (the digits become 0..9; a byte above 9, or with bit 7 set, is no digit. A carry
+        // out of a byte with bit 7 set only affects the bytes above, after the first one
+        // that count_trailing_zeros finds.)
+        const std::uint64_t x = read_eight_bytes(p) ^ (ones * 0x30u);
+        const std::uint64_t not_digit = ((x + (ones * 0x76u)) | x) & (ones * 0x80u);
+        if (not_digit != 0)
+        {
+            return p + (static_cast<std::size_t>(count_trailing_zeros(not_digit)) / 8);
+        }
+        p += 8;
+    }
+    while (p != e && is_digit(*p))
+    {
+        ++p;
+    }
+    return p;
+}
+
+/// whether the n bytes at p are ASCII digits (n > 0)
+inline bool all_digits(const unsigned char* p, std::size_t n) noexcept
+{
+    const auto digits = [](const unsigned char* q)
+    {
+        constexpr std::uint64_t ones = 0x0101010101010101ull;
+        const std::uint64_t x = read_eight_bytes(q) ^ (ones * 0x30u);
+        return (((x + (ones * 0x76u)) | x) & (ones * 0x80u)) == 0;
+    };
+    if (n >= 8)
+    {
+        for (std::size_t i = 0; i + 8 < n; i += 8)
+        {
+            if (!digits(p + i))
+            {
+                return false;
+            }
+        }
+        return digits(p + n - 8); // (overlapping the bytes before: they are digits)
+    }
+    for (std::size_t i = 0; i < n; ++i)
+    {
+        if (!is_digit(p[i]))
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+/// Whether a float token has the shape that the parser records for most of
+/// them: [-]digits.digits, with the numbers of digits of the node's layout
+/// (extra). Then the token is a number of that layout, and the general scan
+/// that follows is not needed.
+inline bool plain_float_token(const unsigned char* s, std::size_t len, std::uint16_t extra) noexcept
+{
+    const std::size_t int_digits = extra & 0xFFu;
+    const std::size_t frac_digits = extra >> 8u;
+    if (int_digits == 0 || int_digits >= 255 || frac_digits == 0 || frac_digits >= 255 || len == 0)
+    {
+        return false;
+    }
+    const std::size_t negative = *s == '-' ? 1 : 0;
+    if (len != negative + int_digits + 1 + frac_digits)
+    {
+        return false;
+    }
+    const unsigned char* const p = s + negative;
+    return !(int_digits > 1 && *p == '0') && p[int_digits] == '.' && all_digits(p, int_digits) && all_digits(p + int_digits + 1, frac_digits);
+}
+
 /// whether [s, s + len) is a JSON number (the grammar the parser accepts)
 inline bool scan_number_token(const unsigned char* s, std::size_t len, number_token& t)
 {
@@ -273,11 +348,7 @@ inline bool scan_number_token(const unsigned char* s, std::size_t len, number_to
     }
     else if (*p >= '1' && *p <= '9')
     {
-        do
+        p = digit_run(p + 1, e);
-        {
-            ++p;
-        }
-        while (p != e && is_digit(*p));
     }
     else
     {
@@ -289,10 +360,7 @@ inline bool scan_number_token(const unsigned char* s, std::size_t len, number_to
     if (p != e && *p == '.')
     {
         const unsigned char* const f0 = ++p;
-        while (p != e && is_digit(*p))
+        p = digit_run(p, e);
-        {
-            ++p;
-        }
         if (p == f0)
         {
             return false;
@@ -403,10 +471,15 @@ struct float_range
 template<typename Check>
 bool check_distinct_ranges(std::vector<byte_range>& ranges, Check check)
 {
-    std::sort(ranges.begin(), ranges.end(), [](const byte_range & a, const byte_range & b)
+    // (save() writes the ranges in the order of the nodes, which is sorted already)
+    const auto before = [](const byte_range & a, const byte_range & b)
     {
         return a.off != b.off ? a.off < b.off : a.len < b.len;
-    });
+    };
+    if (!std::is_sorted(ranges.begin(), ranges.end(), before))
+    {
+        std::sort(ranges.begin(), ranges.end(), before);
+    }
     std::size_t end = 0;
     for (std::size_t i = 0; i < ranges.size(); ++i)
     {
@@ -428,7 +501,8 @@ bool check_distinct_ranges(std::vector<byte_range>& ranges, Check check)
 /// record layouts that match it), tokens must not overlap.
 inline bool check_float_ranges(std::vector<float_range>& ranges, const unsigned char* text)
 {
-    std::sort(ranges.begin(), ranges.end(), [](const float_range & a, const float_range & b)
+    // (save() writes the tokens in the order of the nodes, which is sorted already)
+    const auto before = [](const float_range & a, const float_range & b)
     {
         if (a.off != b.off)
         {
@@ -439,7 +513,11 @@ inline bool check_float_ranges(std::vector<float_range>& ranges, const unsigned
             return a.len < b.len;
         }
         return a.extra < b.extra;
-    });
+    };
+    if (!std::is_sorted(ranges.begin(), ranges.end(), before))
+    {
+        std::sort(ranges.begin(), ranges.end(), before);
+    }
     std::size_t end = 0;
     std::size_t i = 0;
     while (i < ranges.size())
@@ -449,14 +527,18 @@ inline bool check_float_ranges(std::vector<float_range>& ranges, const unsigned
         {
             return false;
         }
-        number_token t{};
         const unsigned char* const s = text + r.off;
-        if (!scan_number_token(s, r.len, t) || !float_token_finite(s, r.len, t))
+        std::uint16_t layout = r.extra;
+        if (!plain_float_token(s, r.len, r.extra))
         {
-            return false;
+            number_token t{};
+            if (!scan_number_token(s, r.len, t) || !float_token_finite(s, r.len, t))
+            {
+                return false;
+            }
+            // the digit layout the parser records (or "many", as compaction writes it)
+            layout = float_layout(t);
         }
-        // the digit layout the parser records (or "many", as compaction writes it)
-        const std::uint16_t layout = float_layout(t);
         for (; i < ranges.size() && ranges[i].off == r.off && ranges[i].len == r.len; ++i)
         {
             if (ranges[i].extra != layout && ranges[i].extra != 0xFFFFu)

include/nlohmann/json_view.hpp

@@ -723,8 +723,12 @@ class basic_json_view
     template<typename, bool> friend class basic_json_document;
     template<typename, bool> friend class basic_json_view;
     template<typename, typename> friend class detail::view::editor;
+    template<typename, typename> friend class detail::view::view_side;
     friend iterator;
 
+    /// whether the view is one of an editable document
+    static constexpr bool is_editable = Editable;
+
     basic_json_view(const document_data* d, const node* n) noexcept
         : m_doc(d), m_node(n)
     {}

tests/src/unit-json_view_dump.cpp

@@ -345,6 +345,35 @@ TEST_CASE("json_view comparison")
         }
     }
 
+    SECTION("objects whose first keys differ or repeat")
+    {
+        const std::array<const char*, 17> texts =
+        {
+            {
+                R"({"a":1,"b":2})", R"({"a":1,"c":2})", R"({"b":1,"a":2})", R"({"a":1,"a":2,"b":3})", R"({"a":2,"b":3})",
+                R"({"a":1,"b":1,"a":2})", R"({"a":2,"b":1})", R"({"a":1,"a":2})", R"({"b":1})", R"({"a":1,"b":2,"c":3,"d":4,"e":5})",
+                R"({"a":1,"b":2,"c":3,"d":4,"f":5})", R"({"a":1,"b":2,"c":3,"a":4,"e":5})", R"({"a":4,"b":2,"c":3,"e":5})",
+                R"({"\u0061":1,"b":2})", R"({})", R"([{"a":1,"b":2}])", R"([{"a":1,"c":2}])"
+            }
+        };
+        for (const char* const x : texts)
+        {
+            for (const char* const y : texts)
+            {
+                CAPTURE(x)
+                CAPTURE(y)
+                const ordered_json_document dx = ordered_json_document::parse(x);
+                const ordered_json_document dy = ordered_json_document::parse(y);
+                const ordered_json_editable_document ex = ordered_json_editable_document::parse(x);
+                const ordered_json jx = ordered_json::parse(x);
+                const ordered_json jy = ordered_json::parse(y);
+                CHECK((dx.root() == dy.root()) == (jx == jy));
+                CHECK((dx.root() == jy) == (jx == jy));
+                CHECK((ex.root() == dy.root()) == (jx == jy));
+            }
+        }
+    }
+
     SECTION("numbers, duplicate keys, member order")
     {
         const auto same = [](const char* x, const char* y)
@@ -385,6 +414,151 @@ TEST_CASE("json_view comparison")
         CHECK(!(null_document.root() == discarded));
     }
 
+    SECTION("values that are the same text, or the same value written differently, at any depth")
+    {
+        // nested arrays and objects around depths where the walk over equal text gives up
+        for (const int depth :
+                {
+                    1, 5, 47, 48, 49, 50, 60, 300
+                })
+        {
+            CAPTURE(depth)
+            std::string head;
+            std::string tail;
+            for (int i = 0; i < depth; ++i)
+            {
+                head += i % 2 == 0 ? R"({"k":[1,"s",{"x":true},)" : R"([null,2.5,{"y":)";
+                tail.insert(0, i % 2 == 0 ? "]}" : "}]");
+            }
+            // the same text, one number changed, and one number written differently
+            const auto with_number = [&](const char* number)
+            {
+                std::string result = head;
+                result += number;
+                result += tail;
+                return result;
+            };
+            const std::string text = with_number("7");
+            const std::string changed = with_number("8");
+            const std::string spelled = with_number("7.0");
+            const json_document a = json_document::parse(text);
+            const json_document b = json_document::parse(text);
+            const json_document c = json_document::parse(changed);
+            const json_document d = json_document::parse(spelled);
+            CHECK(a.root() == b.root());
+            CHECK(a.root() != c.root());
+            CHECK(c.root() != a.root());
+            CHECK(a.root() == d.root());
+            CHECK(d.root() == a.root());
+            CHECK(a.root() == json::parse(text));
+            CHECK(a.root() != json::parse(changed));
+            CHECK(json::parse(spelled) == a.root());
+            const nlohmann::json_editable_document e = nlohmann::json_editable_document::parse(text);
+            CHECK(a.root() == e.root());
+            CHECK(e.root() == a.root());
+            CHECK(c.root() != e.root());
+            CHECK(e.root() == e.root());
+            const ordered_json_document oa = ordered_json_document::parse(text);
+            const ordered_json_document oc = ordered_json_document::parse(changed);
+            CHECK(oa.root() != oc.root());
+            CHECK(oa.root() == ordered_json::parse(text));
+            CHECK(oc.root() != ordered_json::parse(text));
+        }
+
+        // not the same text, but the same value
+        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);
+            const bool equal = dx.root() == dy.root();
+            CHECK(equal == (json::parse(x) == json::parse(y)));
+            CHECK(equal == (dx.root() == json::parse(y)));
+            return equal;
+        };
+        CHECK(same(R"({"a":1,"a":2})", R"({"a":3,"a":2})"));
+        CHECK(same(R"({"a":1,"b":[1,{"c":2,"c":3}]})", R"({"b":[1,{"c":9,"c":3}],"a":1})"));
+        CHECK(!same(R"({"a":1,"a":2})", R"({"a":2,"a":3})"));
+        CHECK(same("[1.0,-0,0,1e2]", "[1.00,0,-0,100.0]"));
+        CHECK(same(R"(["\u00e9","\n"])", "[\"\xc3\xa9\",\"\\n\"]"));
+        CHECK(!same(R"({"a":[1,2,{"b":null}]})", R"({"a":[1,2,{"b":false}]})"));
+        CHECK(!same(R"({"a":[1,2,{"b":null}]})", R"({"a":[1,2,{"c":null}]})"));
+        CHECK(!same(R"({"a":[1,2,{"b":null}]})", R"({"a":[1,2,{"b":null,"c":1}]})"));
+
+        // edited documents: moved sequences, links, and values of new nodes
+        nlohmann::json_editable_document edited = nlohmann::json_editable_document::parse(R"({"a":[1,2,3],"b":{"c":"d"},"e":0.5})");
+        const json_document plain = json_document::parse(R"({"a":[1,2,3,4],"b":{"c":"x","y":null},"e":0.5,"z":[]})");
+        edited.push_back(edited.root()["a"], 4);
+        edited.set(edited.root()["b"], "c", "x");
+        edited.set(edited.root()["b"], "y", nullptr);
+        edited.set(edited.root(), "z", json::array());
+        CHECK(edited.root() == plain.root());
+        CHECK(plain.root() == edited.root());
+        edited.erase(edited.root()["a"], 0);
+        CHECK(edited.root() != plain.root());
+        CHECK(edited.root()["a"] == json::parse("[2,3,4]"));
+        const json_document tail = json_document::parse("[2,3,4]");
+        CHECK(edited.root()["a"] == tail.root());
+    }
+
+    SECTION("large documents, with a difference at any place")
+    {
+        const auto make = [](std::size_t count, std::size_t changed, bool swap_members)
+        {
+            std::string text = R"({"b":1,"list":[)";
+            for (std::size_t i = 0; i < count; ++i)
+            {
+                text += (i != 0 ? "," : "");
+                const std::string id = std::to_string(i == changed ? i + 1 : i);
+                if (swap_members && i % 3 == 0)
+                {
+                    text += R"({"v":[1.5,"s",{"k":)";
+                    text += id;
+                    text += R"(}],"id":)";
+                    text += id;
+                    text += "}";
+                }
+                else
+                {
+                    text += R"({"id":)";
+                    text += id;
+                    text += R"(,"v":[1.5,"s",{"k":)";
+                    text += id;
+                    text += "}]}";
+                }
+            }
+            return text + R"(],"a":{"y":2,"x":3}})";
+        };
+        const std::size_t count = 3000;
+        for (const std::size_t changed :
+                {
+                    count, std::size_t{0}, std::size_t{1}, count / 2, count - 1
+                })
+        {
+            for (const bool swap :
+                    {
+                        false, true
+                    })
+            {
+                CAPTURE(changed)
+                CAPTURE(swap)
+                const std::string text_a = make(count, count, false);
+                const std::string text_b = make(count, changed, swap);
+                const json_document a = json_document::parse(text_a);
+                const json_document b = json_document::parse(text_b);
+                const bool equal = changed == count;
+                CHECK((a.root() == b.root()) == equal);
+                CHECK((b.root() == a.root()) == equal);
+                CHECK((a.root() == json::parse(text_b)) == equal);
+                CHECK((json::parse(text_b) == a.root()) == equal);
+                CHECK((a.root()["list"] == b.root()["list"]) == equal);
+                const ordered_json_document oa = ordered_json_document::parse(text_a);
+                const ordered_json_document ob = ordered_json_document::parse(text_b);
+                CHECK((oa.root() == ob.root()) == (equal && !swap));
+                CHECK((oa.root() == ordered_json::parse(text_b)) == (equal && !swap));
+            }
+        }
+    }
+
     SECTION("deep nesting")
     {
         const std::string deep = std::string(100000, '[') + std::string(100000, ']');

tests/src/unit-json_view_image.cpp

@@ -682,6 +682,66 @@ TEST_CASE("json_view images: ownership")
 #if !defined(JSON_NOEXCEPTION)
 TEST_CASE("json_view images: errors")
 {
+#if !defined(JSON_NOEXCEPTION)
+    SECTION("float tokens: a changed byte is accepted if the text is still a number with the digits the node records")
+    {
+        for (const char* const token :
+                {
+                    "-12.375", "0.5", "123456.0", "-0.0", "9999999999999999999.5", "0.000000000000000000000001", "1.25e10", "5E-3"
+                })
+        {
+            CAPTURE(token)
+            const std::string text = std::string("[") + token + "]";
+            const json_document d = json_document::parse(text);
+            const std::vector<std::uint8_t> image = d.save();
+            const std::size_t at = text_at(image) + 1; // the first byte of the token
+            const std::uint16_t recorded = node_at(image, 1).extra;
+            CHECK(loaded_dump(image) == json::parse(text).dump());
+            for (std::size_t pos = 0; token[pos] != '\0'; ++pos)
+            {
+                for (unsigned int byte = 0; byte < 256; ++byte)
+                {
+                    std::vector<std::uint8_t> changed = image;
+                    changed[at + pos] = static_cast<std::uint8_t>(byte);
+                    std::string t = token;
+                    t[pos] = static_cast<char>(byte);
+                    // the digits of the integer part and of the fraction of the changed token
+                    std::size_t integer = 0;
+                    std::size_t fraction = 0;
+                    std::size_t k = (t[0] == '-') ? 1 : 0;
+                    for (; k < t.size() && t[k] >= '0' && t[k] <= '9'; ++k)
+                    {
+                        ++integer;
+                    }
+                    if (k < t.size() && t[k] == '.')
+                    {
+                        for (++k; k < t.size() && t[k] >= '0' && t[k] <= '9'; ++k)
+                        {
+                            ++fraction;
+                        }
+                    }
+                    // (as a JSON text, the token may have white space around it)
+                    const bool float_token = json::accept(t) && t.find_first_of(std::string(" \t\r\n\0", 5)) == std::string::npos && (t.find('.') != std::string::npos || t.find_first_of("eE") != std::string::npos)
+                                             && ((integer | (fraction << 8U)) == recorded);
+                    CAPTURE(pos)
+                    CAPTURE(byte)
+                    std::string result;
+                    try
+                    {
+                        result = loaded_dump(changed);
+                    }
+                    catch (const json::parse_error& e)
+                    {
+                        CHECK(std::string(e.what()) == check_failed);
+                        result = "rejected";
+                    }
+                    CHECK((result != "rejected") == float_token);
+                }
+            }
+        }
+    }
+#endif
+
     SECTION("a literal as the root: dump() after loading")
     {
         for (const char* text :