libwebsockets/READMEs/README.lws_struct.md
Andy Green 38fb0e31da lws_struct
lws_struct JSON + sqlite3 serializer and deserializer


See READMEs/README.lws_struct.md
2019-04-06 06:08:47 +08:00

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Markdown

# lws_struct
## Overview
lws_struct provides a lightweight method for serializing and deserializing C
structs to and from JSON, and to and from sqlite3.
![lws_struct overview](../doc-assets/lws_struct-overview.svg)
- you provide a metadata array describing struct members one-time, then call
generic apis to serialize and deserialize
- supports flat structs, single child struct pointers, and unbounded arrays /
linked-lists of child objects automatically using [lws_dll2 linked-lists](./README.lws_dll.md)
- supports boolean and C types char, int, long, long long in explicitly signed
and unsigned forms
- supports both char * type string members where the unbounded content is
separate and pointed to, and fixed length char array[] type members where
the content is part of the struct
- huge linear strings are supported by storing to a temp lwsac of chained chunks,
which is written into a single linear chunk in the main lwsac once the
total string length is known
- deserialization allocates into an [lwsac](../lib/misc/lwsac/README.md), so everything is inside as few
heap allocations as possible while still able to expand to handle arbitrary
array or strins sizes
- when deserialized structs are finished with, a single call to free the
lwsac frees the whole thing without having to walk it
- stateful serializaton and deserialization allows as-you-get packets incremental
parsing and production of chunks of as-you-can-send incremental serialization
output cleanly
## Examples