deploy: a49242f088

features/json_view/index.md

@@ -139,7 +139,7 @@ true
 
 - **Only 64-bit integers.** `basic_json_document<BasicJsonType>` requires `BasicJsonType::number_integer_t` and `number_unsigned_t` to both be 64 bits wide; this is a compile-time `static_assert`.
 - **A 4 GiB input limit.** An input of 4294967280 bytes (4 GiB minus 16 bytes) or more throws [`out_of_range.416`](https://json.nlohmann.me/home/exceptions/#jsonexceptionout_of_range416), a limit `basic_json::parse()` does not have. It keeps an index entry at 16 bytes: offsets and counts are 32 bits wide. The limit is 16 bytes below 2^32, because the parser reads in 16-byte steps, and a position one step past the end must still fit.
-- **A stream is always read to its end.** There is no partial/streaming read of an `std::istream`: the stream is read to its end into a buffer the document owns, and parsing starts after that.
+- **A stream is always read to its end.** There is no partial/streaming read of an `std::istream`: the stream is read to its end into a buffer the document owns, and parsing starts after that. For a file, reading it into a `std::string` yourself and parsing that (an lvalue is borrowed) is therefore not more expensive in memory, and was about 6 to 12 % faster than parsing from an `std::ifstream`.
 - **Fewer source positions after edits.** With [`JSON_DIAGNOSTIC_POSITIONS`](https://json.nlohmann.me/api/macros/json_diagnostic_positions/index.md) enabled, [`materialize()`](https://json.nlohmann.me/api/basic_json_view/materialize/index.md) sets the same positions as `basic_json::parse()`. In an [editable document](https://json.nlohmann.me/api/json_editable_document/index.md), a value written by an edit has none, and neither has an array or object whose elements changed or whose last element has none; a `basic_json` value keeps its positions when it is changed. See [`materialize()`](https://json.nlohmann.me/api/basic_json_view/materialize/#notes).
 - **Objects iterate in document order.** [`begin()`](https://json.nlohmann.me/api/basic_json_view/begin/index.md)/ [`end()`](https://json.nlohmann.me/api/basic_json_view/end/index.md) and [`items()`](https://json.nlohmann.me/api/basic_json_view/items/index.md) visit an object's members in the order they appear in the source text. `basic_json`'s default `object_t` is a `std::map`, which sorts by key, so iterating a [`materialize()`](https://json.nlohmann.me/api/basic_json_view/materialize/index.md)d value can print members in a different order than iterating the view they came from.
 - **Chained access is safe.** [`operator[]`](https://json.nlohmann.me/api/basic_json_view/operator%5B%5D/index.md) with a missing key, an index out of range, or an unresolvable JSON pointer returns a [discarded](https://json.nlohmann.me/api/basic_json_view/is_discarded/index.md) view, and `operator[]` on a discarded view returns a discarded view without throwing: `v["a"]["b"][0]` can be tested once at the end. Type errors on values that exist (a key on an array, an index on an object) still throw, and [`at`](https://json.nlohmann.me/api/basic_json_view/at/index.md) throws for every missing value.