https://github.com/quartzjer/js0n

Flexible Zero-Footprint JSON Parser in C
https://github.com/quartzjer/js0n

Last synced: 3 months ago
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Flexible Zero-Footprint JSON Parser in C

• Host: GitHub
• URL: https://github.com/quartzjer/js0n
• Owner: quartzjer
• License: unlicense
• Created: 2010-09-22T12:08:16.000Z (about 14 years ago)
• Default Branch: master
• Last Pushed: 2024-05-15T22:34:07.000Z (6 months ago)
• Last Synced: 2024-07-05T15:14:37.852Z (4 months ago)
• Language: C
• Homepage:
• Size: 46.9 KB
• Stars: 334
• Watchers: 20
• Forks: 48
• Open Issues: 4
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
# js0n - Flexible Zero-Footprint JSON Parser in C

A one-pass minimal overhead walk of the raw bytes, using each one as an index into a jump table to determine state transitions.

* public domain or MIT license, single js0n.c file with one function

* easy to use, just returns a given key-value pair location in the JSON string

* no dependencies, embedded friendly

* requires no memory/malloc or copying, uses only what is passed in (up to `int` max length)

* more flexible than strict JSON and allows bare keys (non-validating)

* optimized for high speed scanning/routing of small chunks of json, stops parsing upon match

* safely errors on anything really bad (binary, NULLs, etc)

Parsing this:

````json

{

    "barbar": [

        1,

        2,

        3

    ],

    "foo": "bar",

    "obj": {

        "a": "b"

    }

}

````

Using `val = js0n("barbar", 6, json, strlen(json), &vlen)` would return a val pointing to `[1,2,3]` and set vlen to `7`.

For arrays, pass `NULL` as the key, and the array offset as the second argument.

When the value is not found `NULL` is returned, if there were any parsing errors then vlen will be set to `-1`.

To determine if the returned value is an actual JSON string or a bare value (like `"true"` vs `true`), simply check if it starts with a quote character via `if(val && *(val-1) == '"')`.

For more usage examples see the [test.json](test/test.json) and [test.c](test/test.c).

## History

See [v1.0](https://github.com/quartzjer/js0n/tree/v1.0) for the original `js0n` function that returned an index of offsets for all key/values in one pass.