deploy: a47170346a
This commit is contained in:
1 parent
b36f8a9821
commit
11a863958e
1180 files changed
+14211
-6025
No files matched your search
@@ -6,13 +6,13 @@ std::vector<std::uint8_t> save() const;
|
||||
|
||||
Writes the document as an *image*: a byte buffer that [`load`](load.md) reads back without parsing. The image holds
|
||||
the node index, the source text (plus, for an edited document, the number tokens edits wrote), and the decoded
|
||||
strings (plus the strings edits wrote) -- everything [`root()`](root.md) needs, with nothing left to parse.
|
||||
strings (plus the strings edits wrote) — everything [`root()`](root.md) needs, with nothing left to parse.
|
||||
|
||||
An edited document is written in its *current* state, with its values in document order, the way the library's own
|
||||
parser would have produced them for that JSON text: a member [`set`](set.md) added goes at the end, an
|
||||
[`erase`](erase.md)d member leaves no trace, and a float that is not finite (NaN or positive/negative infinity)
|
||||
becomes null, the same substitution [`dump()`](../basic_json_view/dump.md) makes. The same document always saves to
|
||||
the same bytes -- also across `BasicJsonType` and the [`view_mode`](../view_mode.md), since the image reflects document order and
|
||||
the same bytes — also across `BasicJsonType` and the [`view_mode`](../view_mode.md), since the image reflects document order and
|
||||
values only, not which specialization produced them.
|
||||
|
||||
## Return value
|
||||
@@ -28,11 +28,11 @@ exactly as it was, and the partially built image is discarded with the exception
|
||||
## Exceptions
|
||||
|
||||
Throws [`type_error.320`](../../home/exceptions.md#jsonexceptiontype_error320) if the document is
|
||||
[discarded](is_discarded.md) -- a default-constructed document, or one a failed [`parse()`](parse.md)/
|
||||
[discarded](is_discarded.md) — a default-constructed document, or one a failed [`parse()`](parse.md)/
|
||||
[`read()`](read.md) with `allow_exceptions == false` left discarded.
|
||||
|
||||
Throws [`out_of_range.416`](../../home/exceptions.md#jsonexceptionout_of_range416) if the node count, the text, or
|
||||
the decoded strings of the image would individually reach 4 GiB -- the same 32-bit offsets
|
||||
the decoded strings of the image would individually reach 4 GiB — the same 32-bit offsets
|
||||
[`parse()`](parse.md#exceptions) and, for edits, [`set`](set.md)/[`push_back`](push_back.md) are already limited to.
|
||||
|
||||
!!! failure "Example messages"
|
||||
@@ -55,13 +55,13 @@ up in the image.
|
||||
and the sizes of the text and the decoded strings, all little-endian), followed by the nodes
|
||||
([16 bytes each](../../home/architecture.md#node-index-of-json-views)), the text and a `#!cpp '\0'`, and the decoded
|
||||
strings and a `#!cpp '\0'`. [`load`](load.md) checks the header, and the sizes it describes, before reading anything
|
||||
else -- see [`load`'s Exceptions](load.md#exceptions).
|
||||
else — see [`load`'s Exceptions](load.md#exceptions).
|
||||
|
||||
!!! warning "Experimental"
|
||||
|
||||
The image format is versioned but not yet stable: it may change in an incompatible way before it is declared
|
||||
stable. Use images to cache a document within one build of the library, or to hand one to another process running
|
||||
the *same* build on the *same* (little-endian) machine -- not as a long-term storage format. Keep the original
|
||||
the *same* build on the *same* (little-endian) machine — not as a long-term storage format. Keep the original
|
||||
JSON text if you need to read a saved document back with a future library version.
|
||||
|
||||
**Little-endian targets only.** The image is written as raw little-endian bytes, with no byte-swapping. On a
|
||||
@@ -72,8 +72,8 @@ big-endian reader could not interpret correctly.
|
||||
|
||||
??? example "Caching a parsed document as an image"
|
||||
|
||||
The example below saves a parsed configuration as an image -- the way a service might cache one to answer later
|
||||
requests without parsing the text again -- and confirms that loading it back gives exactly the same result as
|
||||
The example below saves a parsed configuration as an image — the way a service might cache one to answer later
|
||||
requests without parsing the text again — and confirms that loading it back gives exactly the same result as
|
||||
parsing did, and that saving is deterministic.
|
||||
|
||||
```cpp
|
||||
@@ -121,8 +121,8 @@ big-endian reader could not interpret correctly.
|
||||
|
||||
## See also
|
||||
|
||||
- [load](load.md) - read an image written by `save()`
|
||||
- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
|
||||
- [`load`](load.md) - read an image written by `save()`
|
||||
- [`owns_source`](owns_source.md) - return whether the document holds its own copy of the text
|
||||
- [`basic_json_view::dump`](../basic_json_view/dump.md) - serialize the document to JSON text instead of an image
|
||||
- [Images](../../features/json_view.md#images) - why and when to use images
|
||||
|
||||
|
||||
Reference in new issue
Block a user