Niels Lohmann
60107eda3f
* Read ND-arrays of half floats and enforce the char limit in ND-arrays BJData N-dimensional arrays with element type 'h' (float16) failed to read with a misleading parse_error.112, because the reader's dtype name table lacked 'h'. It now maps to "half", the JData name. The writer still does not pack "half"; such an object is written as a plain object and reads back equal. BJData limits 'C' (char) to 0..127 in Draft 2 and Draft 3, and the 1-D reader enforces this, but ND-arrays with _ArrayType_ "char" wrote values up to 255 as 'C' elements and read them back without a check. The writer now only packs values in 0..127 (others fall back to a plain object that round-trips), and the reader rejects 'C' elements above 127 with parse_error.113 like the 1-D reader. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: correct and complete the BJData documentation Verify the BJData chapter against the library and the Draft 2/3/4 specifications and fix what did not match: - bjdata.md: correct the list of unused markers (N, not Z), the ND-array example (3x2, not 2x3), the conditions under which an object is packed as an ND-array (exactly three keys, row vectors, float-only elements for single/double, char 0..127, byte only in Draft 3), the binary table row and notes (which flag/draft combinations write [$B), the "$" type restriction (Draft 3, Z is excluded too), the H marker in the deserialization table, and the claim of a complete deserialization mapping. Document the supported drafts, that Draft 4 (SoA containers, extension type E) and column-major ND-arrays are rejected, ND-arrays of half floats, duplicate object keys, and link the Draft 3 specifications instead of master. - Add an API page for basic_json::bjdata_version_t with an example, and link it from the nav, the API index and to_bjdata. - Update binary_formats/index.md and binary_values.md, which still claimed that BJData has no binary type, and fix a wrong byte comment there. - Document parse_error.115 and the out_of_range.408 cases for from_bjdata, the precise other_error.502 condition for to_bjdata, and reword the note on truncated unsigned integers in exceptions.md (only ND-array elements were truncated before 3.13.0). Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Regenerate single_include and apply astyle Result of make amalgamate (including make pretty) for the preceding changes. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Address review of the BJData documentation The $ type restriction exists since Draft 2 (Draft 3 added B), $ requires a count, ND char above 127 is rejected on read, and the new API page is listed in alphabetical order in the nav. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * docs: format tables, use the Oxford comma Reformat the tables changed by this PR (BJData serialization and deserialization mappings, completeness and binary-value tables) so all rows are aligned, and add the Oxford comma to lists of three or more items in the added text. Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
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nlohmann::basic_json::bjdata_version_t
enum class bjdata_version_t
{
draft2,
draft3
};
This enumeration is used in to_bjdata to choose the version of the BJData specification to write:
- draft2
- BJData Draft 2 (the default). Binary values are written as arrays of
Uintegers, and ND-arrays with"_ArrayType_": "byte"are written as regular objects, since theBmarker is not part of Draft 2. - draft3
- BJData Draft 3. Binary values are written as
Belements: as an optimized binary array ([$B#) if bothuse_sizeanduse_typeare set, and as an array ofB-prefixed elements otherwise. ND-arrays with"_ArrayType_": "byte"are written as packed arrays ([$B#[...]).
Only the writer is affected by the version. from_bjdata reads the markers of both drafts.
Examples
??? example
The example below shows how the different values of the `bjdata_version_t` influence the serialization of a binary
value with [`to_bjdata`](to_bjdata.md).
```cpp
--8<-- "examples/bjdata_version_t.cpp"
```
Output:
```json
--8<-- "examples/bjdata_version_t.output"
```
See also
Version history
- Added in version 3.12.0.