Address review of the MessagePack documentation

Name parse_error.113 for a 0xC1 map key, move the duplicate-key sentence out of the ext section, and keep the 0xC1 row in marker order.

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

docs/mkdocs/docs/api/basic_json/binary_t.md

@@ -90,8 +90,9 @@ type `#!cpp binary_t*` must be dereferenced.
 
 - MessagePack
     - If a subtype is given and the binary array contains exactly 1, 2, 4, 8, or 16 elements, the fixext family (fixext1,
-      fixext2, fixext4, fixext8) is used. For other sizes, the ext family (ext8, ext16, ext32) is used. The subtype is
-      then added as a signed 8-bit integer.
+      fixext2, fixext4, fixext8, fixext16) is used. For other sizes, the ext family (ext8, ext16, ext32) is used. The
+      subtype is then written as the signed 8-bit ext type: subtypes 128 to 255 map to the negative (reserved) ext
+      types, and on reading the ext type is exposed as an unsigned subtype from 0 to 255.
     - If no subtype is given, the bin family (bin8, bin16, bin32) is used.
 
 - BSON

docs/mkdocs/docs/api/basic_json/cbor_tag_handler_t.md

@@ -15,11 +15,13 @@ error
 :   report a parse error in case of a tag (the `from_cbor` overloads throw a `parse_error` exception by default)
 
 ignore
-:   ignore tags
+:   ignore tags (also in front of a text string map key)
 
 store
 :   store tagged byte strings (for bytes 0xd8..0xdb) as binary values with the tag as subtype; other tagged values are
-    read as if the tag were ignored. If several tags precede a byte string, only the innermost one is stored.
+    read as if the tag were ignored. If several tags precede a byte string, only the tag directly in front of it is
+    stored, and only when it has the form 0xd8..0xdb (a tag 0..23 written as 0xc0..0xd7 is skipped). Tags in front of a
+    text string map key are skipped.
 
 ## Examples
 

docs/mkdocs/docs/api/basic_json/from_cbor.md

@@ -32,8 +32,10 @@ The exact mapping and its limitations are described on a [dedicated page](../../
     
     - an `std::istream` object
     - a `FILE` pointer
-    - a C-style array of characters
-    - a pointer to a null-terminated string of single byte characters
+    - a C-style array of characters (its terminating NUL is read as trailing data: `parse_error.110` unless `strict` is
+      `false`)
+    - a pointer to a null-terminated string of single byte characters (read up to the first 0x00 byte, which is a valid
+      CBOR byte)
     - 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`)
 
@@ -89,8 +91,14 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if unsupported features from CBOR were
   used in the given input or if the input is not valid CBOR
 - Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a map key is not a string (keys of
-  other types are not supported, as JSON object keys are always strings), or if a string value or object key is not
-  valid UTF-8 and `error_handler` is `strict`
+  other types are not supported, as JSON object keys are always strings), if the head of a string or byte string is
+  malformed (including a chunk of the wrong type or an indefinite-length string nested inside an indefinite-length
+  string), or if a string value or object key (or one chunk of an indefinite-length string) is not valid UTF-8 and
+  `error_handler` is `strict`
+- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if an array or map announces
+  a length that `std::size_t` cannot hold, or that equals `std::size_t(-1)` (for example `9B FF FF FF FF FF FF FF FF`)
+- Throws [out_of_range.406](../../home/exceptions.md#jsonexceptionout_of_range406) if a floating-point number does not
+  fit into `number_float_t`
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json/to_cbor.md

@@ -42,7 +42,8 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 
 ## Exception safety
 
-Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
+Strong guarantee: if an exception is thrown, there are no changes in the JSON value. Bytes that were already written to
+the output adapter are not taken back.
 
 ## Exceptions
 

docs/mkdocs/docs/api/basic_json/to_msgpack.md

@@ -53,7 +53,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
   value, array, or object exceeds 4294967295, the maximum MessagePack can store; example:
   `"MessagePack length 4294967296 exceeds maximum of 4294967295"`
 - Throws [`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415) if the subtype of a binary value
-  exceeds 255, the maximum of the MessagePack ext type; example:
+  exceeds 255, the largest value the library can store in the one-byte MessagePack ext type; example:
   `"subtype 70000 is too large for the MessagePack ext type (max 255)"`
 - Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
   not valid UTF-8 and `error_handler` is `strict`

docs/mkdocs/docs/features/binary_formats/cbor.md

@@ -11,7 +11,7 @@ extremely small code sizes, fairly small message size, and extensibility without
 
 ## Byte layout
 
-CBOR encodes every data item as a *head* followed by optional content. The first byte of the head holds the *major type* in its upper three bits (unsigned integer, negative integer, byte string, text string, array, map, tag, or simple/float) and an *additional information* value in its lower five bits. Additional information below 24 is the argument itself (for example, a small integer or a short length); the values 24 to 27 announce that the argument follows in 1, 2, 4, or 8 big-endian bytes. Strings, arrays, and maps are prefixed with their length (or count of elements/pairs), and content follows directly, so a reader always knows how many items to expect without a terminator.
+CBOR encodes every data item as a *head* followed by optional content. The first byte of the head holds the *major type* in its upper three bits (unsigned integer, negative integer, byte string, text string, array, map, tag, or simple/float) and an *additional information* value in its lower five bits. Additional information below 24 is the argument itself (for example, a small integer or a short length); the values 24 to 27 announce that the argument follows in 1, 2, 4, or 8 big-endian bytes. Strings, arrays, and maps are prefixed with their length (or count of elements/pairs), and content follows directly. A reader of definite-length items knows how many items to expect without a terminator; indefinite-length items (additional information 31) are instead closed by the "break" byte 0xFF, which `from_cbor` reads but `to_cbor` never writes.
 
 Consider the following JSON value (shown formatted for readability):
 
@@ -52,16 +52,16 @@ The library uses the following mapping from JSON values types to CBOR types acco
 | null            | `null`                                     | Null                              | 0xF6       |
 | boolean         | `true`                                     | True                              | 0xF5       |
 | boolean         | `false`                                    | False                             | 0xF4       |
-| number_integer  | -9223372036854775808..-2147483649          | Negative integer (8 bytes follow) | 0x3B       |
-| number_integer  | -2147483648..-32769                        | Negative integer (4 bytes follow) | 0x3A       |
-| number_integer  | -32768..-129                               | Negative integer (2 bytes follow) | 0x39       |
-| number_integer  | -128..-25                                  | Negative integer (1 byte follow)  | 0x38       |
+| number_integer  | -9223372036854775808..-4294967297          | Negative integer (8 bytes follow) | 0x3B       |
+| number_integer  | -4294967296..-65537                        | Negative integer (4 bytes follow) | 0x3A       |
+| number_integer  | -65536..-257                               | Negative integer (2 bytes follow) | 0x39       |
+| number_integer  | -256..-25                                  | Negative integer (1 byte follow)  | 0x38       |
 | number_integer  | -24..-1                                    | Negative integer                  | 0x20..0x37 |
 | number_integer  | 0..23                                      | Integer                           | 0x00..0x17 |
 | number_integer  | 24..255                                    | Unsigned integer (1 byte follow)  | 0x18       |
 | number_integer  | 256..65535                                 | Unsigned integer (2 bytes follow) | 0x19       |
 | number_integer  | 65536..4294967295                          | Unsigned integer (4 bytes follow) | 0x1A       |
-| number_integer  | 4294967296..18446744073709551615           | Unsigned integer (8 bytes follow) | 0x1B       |
+| number_integer  | 4294967296..9223372036854775807            | Unsigned integer (8 bytes follow) | 0x1B       |
 | number_unsigned | 0..23                                      | Integer                           | 0x00..0x17 |
 | number_unsigned | 24..255                                    | Unsigned integer (1 byte follow)  | 0x18       |
 | number_unsigned | 256..65535                                 | Unsigned integer (2 bytes follow) | 0x19       |
@@ -95,7 +95,24 @@ see "binary" cells in the table above.
 
 !!! success "Complete mapping"
 
-    The mapping is **complete** in the sense that any JSON value type can be converted to a CBOR value.
+    The mapping is **complete** in the sense that any JSON value type can be converted to a CBOR value, with one
+    exception: an integer outside the range of CBOR integers (only possible with a number type wider than 64 bits)
+    throws [`out_of_range.407`](../../home/exceptions.md#jsonexceptionout_of_range407).
+
+!!! info "Not a deterministic encoding"
+
+    `to_cbor` does not produce the deterministic encoding of
+    [RFC 8949, Section 4.2.1](https://www.rfc-editor.org/rfc/rfc8949.html#section-4.2.1), and not always the preferred
+    serialization of Section 4.1:
+
+    - floating-point numbers are written as single precision (0xFA) when that is exact and as double precision (0xFB)
+      otherwise; half precision (0xF9) is used only for `NaN` and `Infinity`/`-Infinity` (`1.0` is `fa 3f 80 00 00`);
+    - a binary subtype 0..23 is written as `d8 xx` instead of the one-byte tag 0xC0..0xD7 (`d8 01 41 01`);
+    - object members are written in the order of `object_t` (for the default `std::map`: sorted by the key string, not
+      by the encoded key bytes).
+
+    Integers and lengths use the shortest form, and indefinite-length items are never written. Decoders must accept all
+    of this; the RFC does not require the preferred serialization.
 
 !!! info "NaN/infinity handling"
 
@@ -105,9 +122,8 @@ see "binary" cells in the table above.
 
 !!! note
 
-    Prior to version 3.13.0, NaN and Infinity were instead serialized as a CBOR double-precision float (type 0xFB,
-    9 bytes total), because the check used to select a smaller encoding compared magnitudes with NaN, which is
-    always `false` and caused the intended half-precision path to be skipped.
+    Prior to version 3.8.0, NaN and Infinity were instead serialized as a CBOR double-precision float (type 0xFB,
+    9 bytes total).
 
 !!! info "Unused CBOR types"
 
@@ -124,7 +140,6 @@ see "binary" cells in the table above.
       - expected conversions (0xD5..0xD7)
       - simple values (0xE0..0xF3, 0xF8)
       - undefined (0xF7)
-      - half-precision floats (0xF9)
       - break (0xFF)
 
 !!! info "Tagged items"
@@ -226,10 +241,20 @@ string of the same major type, as required by [RFC 8949, Section 3.2.3](https://
     ([RFC 8392](https://www.rfc-editor.org/rfc/rfc8392.html)), cannot be read with this library and need a
     general-purpose CBOR library instead.
 
+    A tag in front of a text string key is handled like a tag in front of a value: it is skipped with
+    `cbor_tag_handler_t::ignore` or `cbor_tag_handler_t::store` and rejected with the default `error`. A tag does not
+    turn a key of another type into a text string.
+
+    A map with duplicate keys is well-formed, but invalid under
+    [RFC 8949, Section 5.3.1](https://www.rfc-editor.org/rfc/rfc8949.html#section-5.3.1). `from_cbor` accepts it and the
+    last value wins; the [SAX interface](../parsing/sax_interface.md) reports every occurrence.
+
 !!! warning "Ill-formed UTF-8 in text strings"
 
     [RFC 8949, Section 3.1](https://www.rfc-editor.org/rfc/rfc8949.html#section-3.1) requires CBOR text strings (major
-    type 3) to be valid UTF-8, but leaves it up to the decoder whether to enforce this, so checking is opt-in: with the
+    type 3) to be valid UTF-8 (a string with ill-formed UTF-8 is "well-formed but invalid"), and
+    [Section 5.3.1](https://www.rfc-editor.org/rfc/rfc8949.html#section-5.3.1) leaves it up to the decoder whether to
+    verify this, so checking is opt-in: with the
     [`error_handler`](../../api/basic_json/from_cbor.md) parameter left at `keep` (the default), `from_cbor()` accepts a
     text string (object keys included) whose bytes are not valid UTF-8 and hands them back unchanged. Passing
     `error_handler_t::strict` makes `from_cbor()` check and throw
@@ -242,9 +267,14 @@ string of the same major type, as required by [RFC 8949, Section 3.2.3](https://
     [`JSON_STRICT_BINARY_UTF8`](../../api/macros/json_strict_binary_utf8.md) is enabled), it throws the same exception
     instead. Byte strings (major type 2) are unaffected, since they are not required to hold text.
 
+    The chunks of an indefinite-length text string are checked one by one, as required by
+    [RFC 8949, Section 3.2.3](https://www.rfc-editor.org/rfc/rfc8949.html#section-3.2.3): a code point cannot be spread
+    over two chunks. With `error_handler_t::strict` such a string throws `parse_error.113`; `replace` and `ignore`
+    sanitize each chunk on its own.
+
 !!! warning "Tagged items"
 
-    Tagged items (0xC0..0xDB) will throw a parse error by default. They can be ignored by passing `cbor_tag_handler_t::ignore` to function `from_cbor`, in which case the tag is skipped and the enclosed data item is parsed on its own. Passing `cbor_tag_handler_t::store` to function `from_cbor` stores tagged byte strings (for bytes 0xd8..0xdb) as binary values with the tag as subtype; other tagged values are read as if the tag were ignored. If several tags precede a byte string, only the innermost one is stored. Note that no tag is ever interpreted: for instance, a text string tagged with tag 0 (date/time) stays a string.
+    Tagged items (0xC0..0xDB) will throw a parse error by default. They can be ignored by passing `cbor_tag_handler_t::ignore` to function `from_cbor`, in which case the tag is skipped and the enclosed data item is parsed on its own. Passing `cbor_tag_handler_t::store` to function `from_cbor` stores tagged byte strings (for bytes 0xd8..0xdb) as binary values with the tag as subtype; other tagged values are read as if the tag were ignored. If several tags precede a byte string, only the tag directly in front of it is stored, and only when it has the form 0xD8..0xDB (a tag 0..23 written as 0xC0..0xD7 is skipped); for example, `D8 05 C1 41 AA` yields subtype `null`, whereas `C1 D8 05 41 AA` yields 5. Tags in front of a text string map key are skipped as well. Note that no tag is ever interpreted: for instance, a text string tagged with tag 0 (date/time) stays a string.
 
 ??? example "Example: deserialize a JSON value from CBOR"
 

docs/mkdocs/docs/features/binary_formats/index.md

@@ -22,7 +22,7 @@ to efficiently encode JSON values to byte vectors and to decode such vectors.
 | BON8        | incomplete: no unsigned integers above int64  | complete                                     |
 | BSON        | incomplete: top-level value must be an object | incomplete, but all JSON types are supported |
 | CBOR        | complete                                      | incomplete, but all JSON types are supported |
-| MessagePack | complete                                      | complete                                     |
+| MessagePack | complete                                      | incomplete, but all JSON types are supported |
 | UBJSON      | complete                                      | complete                                     |
 
 ### Binary values

docs/mkdocs/docs/features/binary_formats/messagepack.md

@@ -11,7 +11,7 @@ extra byte in addition to the strings themselves.
 
 ## Byte layout
 
-MessagePack encodes each value as a one-byte *format marker*, optionally followed by a length or the payload. The marker range is partitioned to keep common values small: small non-negative integers (0 to 127) and small negative integers (-32 to -1) are the marker byte itself; short strings, arrays, and maps (up to 31 or 15 elements) hide their length in the marker's lower bits. Larger values use dedicated markers that announce the width (8, 16, 32, or 64 bits) of the length or number that follows, in big-endian byte order. Like CBOR, containers are length-prefixed, so no terminator is needed.
+MessagePack encodes each value as a one-byte *format marker*, optionally followed by a length or the payload. The marker range is partitioned to keep common values small: small non-negative integers (0 to 127) and small negative integers (-32 to -1) are the marker byte itself; short strings, arrays, and maps (up to 31 bytes for strings and up to 15 elements for arrays and maps) hide their length in the marker's lower bits. Larger values use dedicated markers that announce the width (8, 16, 32, or 64 bits) of the length or number that follows, in big-endian byte order. Like CBOR, containers are length-prefixed, so no terminator is needed.
 
 Consider the following JSON value (shown formatted for readability):
 
@@ -109,8 +109,9 @@ specification:
 !!! note
 
     Prior to version 3.13.0, NaN and Infinity were instead serialized as a MessagePack float 64 (type 0xCB, 9 bytes
-    total), because the check used to select the smaller float 32 encoding compared magnitudes with NaN, which is
-    always `false` and caused the float 32 path to be skipped.
+    total), because the check used to select the smaller float 32 encoding failed for NaN (all comparisons are `false`)
+    and for Infinity and -Infinity (outside the float range checked against `std::numeric_limits<float>::lowest()` and
+    `max()`), so the float 32 path was skipped.
 
 ??? example "Example: serialize a JSON value to MessagePack"
 
@@ -135,6 +136,7 @@ The library maps MessagePack types to JSON value types as follows:
 | fixarray         | array           | 0x90..0x9F |
 | fixstr           | string          | 0xA0..0xBF |
 | nil              | `null`          | 0xC0       |
+| (never used)     | –               | 0xC1       |
 | false            | `false`         | 0xC2       |
 | true             | `true`          | 0xC3       |
 | float 32         | number_float    | 0xCA       |
@@ -167,6 +169,30 @@ The library maps MessagePack types to JSON value types as follows:
 | fixext 16        | binary          | 0xD8       |
 | negative fixint  | number_integer  | 0xE0-0xFF  |
 
+The byte 0xC1 is reserved as "never used" by the specification. As a value it is rejected with
+[`parse_error.112`](../../home/exceptions.md#jsonexceptionparse_error112) (`invalid byte: 0xC1`); as a map key it is
+rejected with [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) and the generic "expected length
+specification" message, because the key is read as a string.
+
+Duplicate keys in a map are accepted; the last value wins.
+
+### Extension types (ext, fixext)
+
+MessagePack ext and fixext values are read as binary values, and the ext type byte is stored as the binary subtype.
+Although the specification defines the type as a signed 8-bit integer (0 to 127 for applications, -128 to -1 reserved,
+with -1 being the Timestamp extension), the library reads it as an unsigned byte: a negative ext type `n` becomes
+subtype `256+n`, so ext type -1 is read as subtype 255 and -128 as subtype 128. The Timestamp extension is not
+interpreted; it is returned as binary with subtype 255. Use
+[`has_subtype()`](../../api/byte_container_with_subtype/has_subtype.md) to tell a `bin` value (no subtype) from an ext
+value (subtype, even if it is 0).
+
+When serializing, a binary value with a subtype is always written as fixext (1, 2, 4, 8, or 16 bytes) or ext, even
+for subtype 0 (`d6 00 01 02 03 04`); a binary value without a subtype is written as bin. Subtypes 128 to 255 are
+written as the reserved negative ext types (255 as -1), so `json::binary({1,2,3,4}, 255)` becomes
+`d6 ff 01 02 03 04`, which other MessagePack libraries decode as a 32-bit timestamp. A subtype above 255 throws
+[`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415). The payload length is limited to
+4294967295 bytes like all other lengths.
+
 !!! info
 
     Any MessagePack output created by `to_msgpack` can be successfully parsed by `from_msgpack`.
@@ -177,7 +203,8 @@ The library maps MessagePack types to JSON value types as follows:
     JSON-compatible [profile](https://github.com/msgpack/msgpack/blob/master/spec.md#profile) sketched in the
     MessagePack specification, this library restricts map keys to `str` values. Maps with keys of any other type are
     rejected with a [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) exception (or, with
-    `allow_exceptions` set to `false`, a discarded value) naming the type of the key that was found, for instance:
+    `allow_exceptions` set to `false`, a discarded value). For most key types the message names the type that was
+    found, for instance:
 
     ```
     [json.exception.parse_error.113] parse error at byte 2: syntax error while parsing MessagePack object key: only string keys are supported, but found nil; last byte: 0xC0
@@ -189,7 +216,7 @@ The library maps MessagePack types to JSON value types as follows:
 !!! warning "Ill-formed UTF-8 in string values"
 
     The MessagePack specification explicitly allows a `str` value (`fixstr`, `str 8`, `str 16`, `str 32`) to contain
-    a byte sequence that is not valid UTF-8, and expects a deserializer to hand the original bytes back unchanged.
+    a byte sequence that is not valid UTF-8, and recommends that a deserializer provide a way to obtain the original bytes.
     This library follows that by default: with its
     [`error_handler`](../../api/basic_json/from_msgpack.md) parameter left at `keep` (the default),
     `from_msgpack()` reads `str` bytes (object keys included) as-is, without validating them, so such a value

docs/mkdocs/docs/features/binary_values.md

@@ -301,6 +301,8 @@ representation using the length of the byte array.
     [`json::from_cbor`](../api/basic_json/from_cbor.md) (see
     [`cbor_tag_handler_t`](../api/basic_json/cbor_tag_handler_t.md)).
 
+    With `ignore`, the subtype is dropped (`"subtype": null`); with `store`, the tag is kept (`"subtype": 42`):
+
     ```json
     {
       "binary": {
@@ -310,11 +312,21 @@ representation using the length of the byte array.
     }
     ```
 
+    ```json
+    {
+      "binary": {
+        "bytes": [202, 254, 186, 190],
+        "subtype": 42
+      }
+    }
+    ```
+
 ### MessagePack
 
 [MessagePack](binary_formats/messagepack.md) supports binary values and subtypes. If a subtype is given, the ext family
-is used. The library will choose the smallest representation among fixext1, fixext2, fixext4, fixext8, ext8, ext16, and
-ext32. The subtype is then added as a signed 8-bit integer.
+is used. The library will choose the smallest representation among fixext1, fixext2, fixext4, fixext8, fixext16, ext8,
+ext16, and ext32. The subtype is then written as the signed 8-bit ext type: subtypes 128 to 255 map to the negative
+(reserved) ext types, and on reading the ext type is exposed as an unsigned subtype from 0 to 255.
 
 If no subtype is given, the bin family (bin8, bin16, bin32) is used.
 

docs/mkdocs/docs/features/types/template_parameters.md

@@ -368,8 +368,7 @@ using array_t = ArrayType<basic_json, AllocatorType<basic_json>>;
   `#!cpp std::from_chars` is not available or declines the token, and `std::strtold` reads up to the null character. A type whose `data()`
   is not null-terminated does not fail to compile; with such a `NumberFloatType` it can silently misparse
   floating-point numbers.
-- `append(const char*, size_type)`, used by [`dump`](../../api/basic_json/dump.md), and `append(const StringType&)`,
-  used by the CBOR reader for indefinite-length strings. The library's internal string concatenation additionally has
+- `append(const char*, size_type)`, used by [`dump`](../../api/basic_json/dump.md) and by the binary readers. The library's internal string concatenation additionally has
   to append a `#!cpp char` and a `#!cpp const char*`; for each it selects between `append(arg)`, `#!cpp operator+=`,
   `append(first, last)`, and `append(data, size)`.
 - The comparison operator `==` against another `StringType`, and `<` for use as a key of the chosen
@@ -678,8 +677,7 @@ using binary_t = nlohmann::byte_container_with_subtype<BinaryType>;
   [`StringType`](#stringtype), whose non-`#!cpp const` `data()` is C++17 and later only.
 - Default-constructible, copy-constructible, and move-constructible.
 - Member functions `size()`, `empty()`, `data()`, `resize()`, `operator[]`, `back()`, `begin()`, `end()`, `cbegin()`,
-  and `cend()` with random-access iterators, and `insert(pos, first, last)`, which the CBOR reader uses to join the
-  chunks of an indefinite-length byte string. `push_back()` is **not** required.
+  and `cend()` with random-access iterators. `push_back()` is **not** required.
 - Comparison operators: `==` is used by
   [`byte_container_with_subtype`](../../api/byte_container_with_subtype/index.md), the relational operators by
   [`basic_json`'s comparison operators](../../api/basic_json/operator_le.md).

docs/mkdocs/docs/home/exceptions.md

@@ -1153,7 +1153,7 @@ A JSON Patch `move` operation's `"from"` location is a proper prefix of its `"pa
 ### json.exception.out_of_range.415
 
 MessagePack's ext type and BSON's binary subtype are each stored in a single byte. This exception is thrown when serializing a
-[`byte_container_with_subtype`](../api/byte_container_with_subtype/index.md) whose subtype exceeds 255.
+[`byte_container_with_subtype`](../api/byte_container_with_subtype/index.md) whose subtype exceeds 255, the largest value the library can store in that byte.
 
 !!! failure "Example message"
 

include/nlohmann/detail/input/binary_reader.hpp

@@ -1218,6 +1218,10 @@ class binary_reader
         // level as required by RFC 8949, Section 3.2.3
         bool indefinite = false;
 
+        // the chunk currently being validated; only used for the chunks of an
+        // indefinite-length string when the UTF-8 check can do something
+        string_t chunk;
+
         while (true)
         {
             if (JSON_HEDLEY_UNLIKELY(!unexpect_eof("string")))
@@ -1237,26 +1241,82 @@ class binary_reader
             }
 
             // a break marker closes the indefinite-length string; outside
-            // of one it falls through to the error below
+            // of one it falls through to the error below. Every chunk has
+            // been checked on its own, so there is nothing left to check.
             if (indefinite && current == 0xFF)
             {
-                return check_string_utf8(result, context);
-            }
-
-            if (JSON_HEDLEY_UNLIKELY(!get_cbor_string_chunk(result, indefinite)))
-            {
-                return false;
+                return true;
             }
 
             if (!indefinite)
             {
-                return check_string_utf8(result, context);
+                return get_cbor_string_chunk(result, false) && check_string_utf8(result, context);
+            }
+
+            if (error_handler == error_handler_t::keep)
+            {
+                // nothing to check: read the chunk directly into the result
+                if (JSON_HEDLEY_UNLIKELY(!get_cbor_string_chunk(result, true)))
+                {
+                    return false;
+                }
+            }
+            else
+            {
+                // RFC 8949, Section 3.2.3: each chunk is a text string of its
+                // own and must be valid UTF-8 by itself, i.e., a code point
+                // cannot be spread over two chunks
+                chunk.clear();
+                if (JSON_HEDLEY_UNLIKELY(!get_cbor_string_chunk(chunk, true) || !check_string_utf8(chunk, context)))
+                {
+                    return false;
+                }
+                result.append(chunk.data(), chunk.size());
             }
 
             get();
         }
     }
 
+    /*!
+    @brief skips the tags in front of a CBOR object key
+
+    A tag may wrap any data item, so it may also wrap a key. Like in front of a
+    value, the tags are skipped for the handlers ignore and store; with the
+    handler error they are left to @ref get_cbor_object_key, which rejects the
+    key. The tag loop is iterative, so the number of tags is not limited by the
+    recursion depth.
+
+    @param[in] tag_handler  how CBOR tags should be treated
+
+    @return whether the tags could be skipped (false on EOF in a tag argument)
+
+    @pre @a current is the first byte of the key
+    */
+    bool skip_cbor_key_tags(const cbor_tag_handler_t tag_handler)
+    {
+        if (tag_handler == cbor_tag_handler_t::error)
+        {
+            return true;
+        }
+
+        // 0xC0..0xDB: tag with the tag number in the head (0xC0..0xD7) or in
+        // the 1, 2, 4, or 8 bytes that follow (0xD8..0xDB)
+        while (current >= 0xC0 && current <= 0xDB)
+        {
+            if (current >= 0xD8)
+            {
+                std::uint64_t tag_to_ignore{};
+                if (JSON_HEDLEY_UNLIKELY(!get_cbor_argument(tag_to_ignore)))
+                {
+                    return false;
+                }
+            }
+            get();
+        }
+        return true;
+    }
+
     /*!
     @brief reads a CBOR object key
 
@@ -1623,6 +1683,10 @@ class binary_reader
 
                 if (top.is_object)
                 {
+                    if (JSON_HEDLEY_UNLIKELY(!skip_cbor_key_tags(tag_handler)))
+                    {
+                        return false;
+                    }
                     if (JSON_HEDLEY_UNLIKELY(!read_object_key<&binary_reader::get_cbor_object_key>(key)))
                     {
                         return false;
@@ -4130,9 +4194,9 @@ class binary_reader
         // sequence), UBJSON, BJData, or BSON requires a decoder to reject
         // ill-formed UTF-8. Checking (and, with @ref error_handler_t::strict,
         // rejecting, or with `replace`/`ignore`, sanitizing) is opt-in via
-        // @ref error_handler, applied once the whole string (all chunks of
-        // an indefinite-length CBOR string included) has been assembled, by
-        // @ref check_string_utf8 at the call site.
+        // @ref error_handler, applied by @ref check_string_utf8 at the call
+        // site to the whole string or, for an indefinite-length CBOR string,
+        // to each chunk on its own (RFC 8949, Section 3.2.3).
         return get_bytes(len, "string", result);
     }
 

include/nlohmann/detail/view/image.hpp

@@ -255,81 +255,6 @@ 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)
 {
@@ -348,7 +273,11 @@ inline bool scan_number_token(const unsigned char* s, std::size_t len, number_to
     }
     else if (*p >= '1' && *p <= '9')
     {
-        p = digit_run(p + 1, e);
+        do
+        {
+            ++p;
+        }
+        while (p != e && is_digit(*p));
     }
     else
     {
@@ -360,7 +289,10 @@ 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;
-        p = digit_run(p, e);
+        while (p != e && is_digit(*p))
+        {
+            ++p;
+        }
         if (p == f0)
         {
             return false;
@@ -471,15 +403,10 @@ struct float_range
 template<typename Check>
 bool check_distinct_ranges(std::vector<byte_range>& ranges, Check check)
 {
-    // (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)
+    std::sort(ranges.begin(), ranges.end(), [](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)
     {
@@ -501,8 +428,7 @@ 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)
 {
-    // (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)
+    std::sort(ranges.begin(), ranges.end(), [](const float_range & a, const float_range & b)
     {
         if (a.off != b.off)
         {
@@ -513,11 +439,7 @@ 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())
@@ -527,18 +449,14 @@ inline bool check_float_ranges(std::vector<float_range>& ranges, const unsigned
         {
             return false;
         }
-        const unsigned char* const s = text + r.off;
-        std::uint16_t layout = r.extra;
-        if (!plain_float_token(s, r.len, r.extra))
-        {
         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))
         {
             return false;
         }
         // the digit layout the parser records (or "many", as compaction writes it)
-            layout = float_layout(t);
-        }
+        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

@@ -743,12 +743,8 @@ 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)
     {}

single_include/nlohmann/json.hpp

@@ -18685,6 +18685,10 @@ class binary_reader
         // level as required by RFC 8949, Section 3.2.3
         bool indefinite = false;
 
+        // the chunk currently being validated; only used for the chunks of an
+        // indefinite-length string when the UTF-8 check can do something
+        string_t chunk;
+
         while (true)
         {
             if (JSON_HEDLEY_UNLIKELY(!unexpect_eof("string")))
@@ -18704,26 +18708,82 @@ class binary_reader
             }
 
             // a break marker closes the indefinite-length string; outside
-            // of one it falls through to the error below
+            // of one it falls through to the error below. Every chunk has
+            // been checked on its own, so there is nothing left to check.
             if (indefinite && current == 0xFF)
             {
-                return check_string_utf8(result, context);
-            }
-
-            if (JSON_HEDLEY_UNLIKELY(!get_cbor_string_chunk(result, indefinite)))
-            {
-                return false;
+                return true;
             }
 
             if (!indefinite)
             {
-                return check_string_utf8(result, context);
+                return get_cbor_string_chunk(result, false) && check_string_utf8(result, context);
+            }
+
+            if (error_handler == error_handler_t::keep)
+            {
+                // nothing to check: read the chunk directly into the result
+                if (JSON_HEDLEY_UNLIKELY(!get_cbor_string_chunk(result, true)))
+                {
+                    return false;
+                }
+            }
+            else
+            {
+                // RFC 8949, Section 3.2.3: each chunk is a text string of its
+                // own and must be valid UTF-8 by itself, i.e., a code point
+                // cannot be spread over two chunks
+                chunk.clear();
+                if (JSON_HEDLEY_UNLIKELY(!get_cbor_string_chunk(chunk, true) || !check_string_utf8(chunk, context)))
+                {
+                    return false;
+                }
+                result.append(chunk.data(), chunk.size());
             }
 
             get();
         }
     }
 
+    /*!
+    @brief skips the tags in front of a CBOR object key
+
+    A tag may wrap any data item, so it may also wrap a key. Like in front of a
+    value, the tags are skipped for the handlers ignore and store; with the
+    handler error they are left to @ref get_cbor_object_key, which rejects the
+    key. The tag loop is iterative, so the number of tags is not limited by the
+    recursion depth.
+
+    @param[in] tag_handler  how CBOR tags should be treated
+
+    @return whether the tags could be skipped (false on EOF in a tag argument)
+
+    @pre @a current is the first byte of the key
+    */
+    bool skip_cbor_key_tags(const cbor_tag_handler_t tag_handler)
+    {
+        if (tag_handler == cbor_tag_handler_t::error)
+        {
+            return true;
+        }
+
+        // 0xC0..0xDB: tag with the tag number in the head (0xC0..0xD7) or in
+        // the 1, 2, 4, or 8 bytes that follow (0xD8..0xDB)
+        while (current >= 0xC0 && current <= 0xDB)
+        {
+            if (current >= 0xD8)
+            {
+                std::uint64_t tag_to_ignore{};
+                if (JSON_HEDLEY_UNLIKELY(!get_cbor_argument(tag_to_ignore)))
+                {
+                    return false;
+                }
+            }
+            get();
+        }
+        return true;
+    }
+
     /*!
     @brief reads a CBOR object key
 
@@ -19090,6 +19150,10 @@ class binary_reader
 
                 if (top.is_object)
                 {
+                    if (JSON_HEDLEY_UNLIKELY(!skip_cbor_key_tags(tag_handler)))
+                    {
+                        return false;
+                    }
                     if (JSON_HEDLEY_UNLIKELY(!read_object_key<&binary_reader::get_cbor_object_key>(key)))
                     {
                         return false;
@@ -21597,9 +21661,9 @@ class binary_reader
         // sequence), UBJSON, BJData, or BSON requires a decoder to reject
         // ill-formed UTF-8. Checking (and, with @ref error_handler_t::strict,
         // rejecting, or with `replace`/`ignore`, sanitizing) is opt-in via
-        // @ref error_handler, applied once the whole string (all chunks of
-        // an indefinite-length CBOR string included) has been assembled, by
-        // @ref check_string_utf8 at the call site.
+        // @ref error_handler, applied by @ref check_string_utf8 at the call
+        // site to the whole string or, for an indefinite-length CBOR string,
+        // to each chunk on its own (RFC 8949, Section 3.2.3).
         return get_bytes(len, "string", result);
     }
 

tests/src/unit-cbor.cpp

@@ -1807,6 +1807,93 @@ TEST_CASE("CBOR")
             CHECK(json::from_cbor(std::vector<uint8_t>({0xa1, 0xff, 0x01}), true, false).is_discarded());
         }
 
+        SECTION("tag in front of a key")
+        {
+            const auto ignore = json::cbor_tag_handler_t::ignore;
+            const auto store = json::cbor_tag_handler_t::store;
+            const json expected = {{"a", 10}};
+
+            // the tags are skipped in front of a text string key, like in
+            // front of a value
+            const std::vector<std::vector<std::uint8_t>> tagged =
+            {
+                {0xA1, 0xC0, 0x61, 0x61, 0x0A},                         // tag in the head
+                {0xA1, 0xD8, 0x05, 0x61, 0x61, 0x0A},                   // 1-byte tag number
+                {0xA1, 0xD9, 0x01, 0x2C, 0x61, 0x61, 0x0A},             // 2-byte tag number
+                {0xA1, 0xDA, 0x00, 0x01, 0x00, 0x00, 0x61, 0x61, 0x0A}, // 4-byte tag number
+                {0xA1, 0xDB, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x61, 0x61, 0x0A}, // 8-byte tag number
+                {0xA1, 0xC0, 0xD8, 0x05, 0xC1, 0x61, 0x61, 0x0A},       // chained tags
+                {0xBF, 0xC0, 0x61, 0x61, 0x0A, 0xFF},                   // indefinite-length map
+                {0xBF, 0x61, 0x62, 0x01, 0xC0, 0x61, 0x61, 0x0A, 0xFF}, // second key tagged
+                {0xA1, 0xC0, 0x7F, 0x61, 0x61, 0xFF, 0x0A},             // indefinite-length text key
+                {0xA1, 0xC0, 0x61, 0x61, 0xC0, 0x0A},                   // tagged key and value
+            };
+
+            for (const auto& input : tagged)
+            {
+                CAPTURE(input)
+                json const j_ignore = json::from_cbor(input, true, true, ignore);
+                json const j_store = json::from_cbor(input, true, true, store);
+                CHECK(j_ignore.at("a") == 10);
+                CHECK(j_store.at("a") == 10);
+                CHECK(j_ignore == j_store);
+            }
+            CHECK(json::from_cbor(tagged[0], true, true, ignore) == expected);
+            CHECK(json::from_cbor(tagged[1], true, true, store) == expected);
+
+            // nested maps
+            CHECK(json::from_cbor(std::vector<std::uint8_t>({0xA1, 0xC0, 0x61, 0x61, 0xA1, 0xD8, 0x05, 0x61, 0x62, 0x01}), true, true, ignore) == json{{"a", {{"b", 1}}}});
+
+            // the tag handler error still rejects every tag
+            for (const auto& input : tagged)
+            {
+                CAPTURE(input)
+                json _;
+                CHECK_THROWS_AS(_ = json::from_cbor(input), json::parse_error&);
+            }
+            {
+                json _;
+                CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<std::uint8_t>({0xA1, 0xD8, 0x05, 0x61, 0x61, 0x0A})), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR object key: only string keys are supported, but found a tag; last byte: 0xD8", json::parse_error&);
+            }
+
+            // a tag does not turn a key of another type into a text string
+            {
+                json _;
+                CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<std::uint8_t>({0xA1, 0xC0, 0x01, 0x01}), true, true, ignore), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR object key: only string keys are supported, but found an unsigned integer; last byte: 0x01", json::parse_error&);
+                CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<std::uint8_t>({0xA1, 0xD8, 0x05, 0x41, 0x61, 0x01}), true, true, store), "[json.exception.parse_error.113] parse error at byte 4: syntax error while parsing CBOR object key: only string keys are supported, but found a byte string; last byte: 0x41", json::parse_error&);
+                CHECK(json::from_cbor(std::vector<std::uint8_t>({0xA1, 0xC0, 0x01, 0x01}), true, false, ignore).is_discarded());
+            }
+
+            // end of input after the tag, or inside the tag number
+            {
+                json _;
+                CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<std::uint8_t>({0xA1, 0xC0}), true, true, ignore), "[json.exception.parse_error.110] parse error at byte 3: syntax error while parsing CBOR string: unexpected end of input", json::parse_error&);
+                CHECK_THROWS_AS(_ = json::from_cbor(std::vector<std::uint8_t>({0xA1, 0xD8}), true, true, ignore), json::parse_error&);
+                CHECK_THROWS_AS(_ = json::from_cbor(std::vector<std::uint8_t>({0xA1, 0xDB, 0x00, 0x00}), true, true, store), json::parse_error&);
+                CHECK_THROWS_AS(_ = json::from_cbor(std::vector<std::uint8_t>({0xBF, 0xC0}), true, true, store), json::parse_error&);
+            }
+
+            // SAX: the key event is reported without the tag (start_object,
+            // key, number_unsigned, end_object are four events)
+            {
+                const std::vector<std::uint8_t> input = {0xA1, 0xC0, 0x61, 0x61, 0x0A};
+                SaxCountdown four(4);
+                CHECK(json::sax_parse(input, &four, json::input_format_t::cbor, true, false, false, ignore));
+                SaxCountdown three(3);
+                CHECK(!json::sax_parse(input, &three, json::input_format_t::cbor, true, false, false, ignore));
+                SaxCountdown error_handler(4);
+                CHECK(!json::sax_parse(input, &error_handler, json::input_format_t::cbor));
+            }
+
+            // a long chain of tags needs no recursion
+            {
+                std::vector<std::uint8_t> input = {0xA1};
+                input.insert(input.end(), 100000, 0xC0);
+                input.insert(input.end(), {0x61, 0x61, 0x0A});
+                CHECK(json::from_cbor(input, true, true, ignore) == expected);
+            }
+        }
+
         SECTION("non-string key (see #2766 and #3381)")
         {
             // only text strings map to JSON object keys; any other key is
@@ -1915,9 +2002,10 @@ TEST_CASE("CBOR")
         {
             json _;
 
-            // the chunks are concatenated as is, without checking that each
-            // chunk is valid UTF-8 on its own (RFC 8949, Section 3.2.3), so
-            // a code point split across two chunks yields a valid string
+            // with the default error handler keep, the chunks are concatenated
+            // as is, without checking that each chunk is valid UTF-8 on its
+            // own (RFC 8949, Section 3.2.3), so a code point split across two
+            // chunks yields a valid string
             CHECK_NOTHROW(_ = json::from_cbor(std::vector<uint8_t>({0x7f, 0x61, 0xc3, 0x61, 0xa9, 0xff})));
             CHECK(_ == "\xc3\xa9");
             CHECK(_.dump() == "\"\xc3\xa9\"");
@@ -1937,6 +2025,63 @@ TEST_CASE("CBOR")
             CHECK(json::from_cbor(std::vector<uint8_t>({0x7f, 0x62, 0xc3, 0xa9, 0x62, 0xc3, 0xb6, 0xff})) == "\xc3\xa9\xc3\xb6");
         }
 
+        SECTION("ill-formed UTF-8 in a chunk of an indefinite-length string (RFC 8949, Section 3.2.3)")
+        {
+            const auto strict = json::error_handler_t::strict;
+            const auto replace = json::error_handler_t::replace;
+            const auto ignore = json::error_handler_t::ignore;
+            const auto keep = json::error_handler_t::keep;
+            const auto tags = json::cbor_tag_handler_t::error;
+
+            // a code point split over two chunks
+            const std::vector<std::uint8_t> split = {0x7f, 0x61, 0xc3, 0x61, 0xa9, 0xff};
+            // a 4-byte code point split over two chunks
+            const std::vector<std::uint8_t> split_emoji = {0x7f, 0x62, 0xf0, 0x9f, 0x62, 0x98, 0x80, 0xff};
+            // the same in an object key
+            const std::vector<std::uint8_t> split_key = {0xa1, 0x7f, 0x61, 0xc3, 0x61, 0xa9, 0xff, 0x01};
+            // a valid chunk followed by one with a truncated code point
+            const std::vector<std::uint8_t> truncated = {0x7f, 0x62, 0x41, 0xc3, 0x61, 0xa9, 0xff};
+
+            // strict: the string is invalid
+            for (const auto& input :
+                    {
+                        split, split_emoji, split_key, truncated
+                    })
+            {
+                CAPTURE(input)
+                json _;
+                CHECK_THROWS_AS(_ = json::from_cbor(input, true, true, tags, strict), json::parse_error&);
+                CHECK(json::from_cbor(input, true, false, tags, strict).is_discarded());
+            }
+            {
+                json _;
+                CHECK_THROWS_WITH_AS(_ = json::from_cbor(split, true, true, tags, strict), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR string: invalid string: ill-formed UTF-8 byte", json::parse_error&);
+                CHECK_THROWS_WITH_AS(_ = json::from_cbor(split_key, true, true, tags, strict), "[json.exception.parse_error.113] parse error at byte 4: syntax error while parsing CBOR key: invalid string: ill-formed UTF-8 byte", json::parse_error&);
+            }
+
+            // replace and ignore: every chunk is sanitized on its own
+            CHECK(json::from_cbor(split, true, true, tags, replace) == "\xEF\xBF\xBD\xEF\xBF\xBD");
+            CHECK(json::from_cbor(split, true, true, tags, ignore) == "");
+            CHECK(json::from_cbor(truncated, true, true, tags, replace) == "A\xEF\xBF\xBD\xEF\xBF\xBD");
+            CHECK(json::from_cbor(truncated, true, true, tags, ignore) == "A");
+            CHECK(json::from_cbor(split_key, true, true, tags, replace) == json{{"\xEF\xBF\xBD\xEF\xBF\xBD", 1}});
+
+            // keep: unchanged, the chunks are concatenated as is
+            CHECK(json::from_cbor(split, true, true, tags, keep) == "\xc3\xa9");
+            CHECK(json::from_cbor(split_emoji, true, true, tags, keep) == "\xf0\x9f\x98\x80");
+
+            // conforming input is unaffected by the error handler
+            const std::vector<std::uint8_t> valid = {0x7f, 0x62, 0xc3, 0xa9, 0x64, 0xf0, 0x9f, 0x98, 0x80, 0x60, 0xff};
+            for (const auto handler :
+                    {
+                        strict, replace, ignore, keep
+                    })
+            {
+                CHECK(json::from_cbor(valid, true, true, tags, handler) == "\xc3\xa9\xf0\x9f\x98\x80");
+                CHECK(json::from_cbor(std::vector<std::uint8_t>({0x7f, 0xff}), true, true, tags, handler) == "");
+            }
+        }
+
         SECTION("many chunks in indefinite-length string")
         {
             constexpr std::size_t chunks = 100000;

tests/src/unit-json_view_compare.cpp

@@ -1,364 +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
-
-#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;
-
-#include "json_view_test_helpers.hpp"
-using json_view_test::generator;
-
-#include <array>
-#include <cstddef>
-#include <string>
-#include <vector>
-
-// These tests were split off unit-json_view_dump.cpp, whose object file got too
-// large for the MinGW assembler ("file too big"). 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("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("objects with duplicate keys, small and large")
-    {
-        // n members with keys in descending order; with duplicates, some keys
-        // repeat later (the first after unique ones in key order); in reverse,
-        // the members are in ascending key order
-        const auto object = [](int n, bool duplicates, bool reverse, int value)
-        {
-            std::string s = "{";
-            for (int i = 0; i < n; ++i)
-            {
-                const int k = reverse ? i : n - 1 - i;
-                s += (i != 0 ? ",\"k" : "\"k") + std::to_string(100 + k) + "\":" + std::to_string(value + k);
-            }
-            if (duplicates)
-            {
-                for (int k = n / 2; k < n; k += 3)
-                {
-                    s += ",\"k" + std::to_string(100 + k) + "\":" + std::to_string(value + k);
-                }
-            }
-            return s + "}";
-        };
-        std::vector<std::string> texts;
-        for (const int n :
-                {
-                    3, 16, 17, 40
-                })
-        {
-            for (const int flags :
-                    {
-                        0, 1, 2, 3
-                    })
-            {
-                texts.push_back(object(n, (flags & 1) != 0, (flags & 2) != 0, 0));
-            }
-            texts.push_back(object(n, true, false, 1)); // other values
-        }
-        // many objects in one comparison (working memory reused across objects)
-        std::string array = "[";
-        std::string array_other = "[";
-        for (std::size_t i = 0; i < texts.size(); ++i)
-        {
-            array += (i != 0 ? "," : "") + texts[i];
-            array_other += (i != 0 ? "," : "") + texts[texts.size() - 1 - i];
-        }
-        texts.push_back(array + "]");
-        texts.push_back(array_other + "]");
-        for (const std::string& x : texts)
-        {
-            for (const std::string& 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 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));
-                const json_document ux = json_document::parse(x);
-                const json uy = json::parse(y);
-                CHECK((ux.root() == uy) == (json::parse(x) == uy));
-            }
-        }
-    }
-
-    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("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, ']');
-        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());
-    }
-}

tests/src/unit-json_view_dump.cpp

@@ -432,6 +432,101 @@ TEST_CASE("json_view 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

tests/src/unit-json_view_image.cpp

@@ -682,64 +682,6 @@ TEST_CASE("json_view images: ownership")
 #if !defined(JSON_NOEXCEPTION)
 TEST_CASE("json_view images: errors")
 {
-    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) // NOLINT(abseil-string-find-str-contains)
-                                             && ((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);
-                }
-            }
-        }
-    }
-
     SECTION("invalid UTF-8 of a decoded string: the compact dump writes it, the others throw")
     {
         const json_document d = json_document::parse(R"({"k\n":"\u00e9x"})");