jsonwriter: small, fast and permissively-license JSON writer written in C

Why do we need this?

This library was designed to meet the following requirements:

• small
• fast
• memory-efficient
• supports full range of UTF8
• written in C, portable, and permissively licensed
• thread safe
• supports custom write functions and write targets (e.g. write to network or pipe or to custom buffer using some custom write function)

The last item was the most difficult to find, but was indispensible for versatile reusability (for example, maybe we will not know, until dynamically at runtime, whether we want to write our JSON to stdout, stderr, another file, a network pipe, or just feed that back into some other process in a chain of data processing.

How to use

create a handle

Write either to a file, or provide your own fwrite-like function and target:

jsonwriter_handle jsonwriter_new_file(FILE *f);
jsonwriter_handle jsonwriter_new(
    size_t (*write)(const void *, size_t, size_t, void *),
    void *write_arg
);

e.g. jsonwriter_handle h = jsonwriter_new(fwrite, stdout)

write your JSON

For example:

jsonwriter_start_object(h);
jsonwriter_object_key(h, "hello");
jsonwriter_str(h, "there!");
jsonwriter_end(h); // or alternatively, for more strict use, `jsonwriter_end_object(h)`

or, in a more concise form:

jsonwriter_start_object(h);
jsonwriter_object_str(h, "hello", "there!"); // similar macros can be used for other types
jsonwriter_end(h);

clean up

jsonwriter_delete(h)

Enjoy!