https://github.com/rdpoor/jems

jems: a stream-based JSON serialized for embedded systems
https://github.com/rdpoor/jems

Last synced: 29 days ago
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jems: a stream-based JSON serialized for embedded systems

• Host: GitHub
• URL: https://github.com/rdpoor/jems
• Owner: rdpoor
• License: mit
• Created: 2022-10-16T14:06:09.000Z (about 2 years ago)
• Default Branch: main
• Last Pushed: 2023-04-15T21:22:00.000Z (over 1 year ago)
• Last Synced: 2024-08-04T04:07:36.678Z (4 months ago)
• Language: C
• Homepage:
• Size: 23.4 KB
• Stars: 9
• Watchers: 2
• Forks: 1
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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• awesome-embedded - jems

README

        
# jems

jems: a stream-based JSON serialized for embedded systems

## About `jems`

`jems` is a compact, stream-based JSON serializer written in pure C for embedded

systems.

`jems` makes it easy generate complex JSON structures, writing the results into

a buffer, string or stream.  Specifically designed for embedded systems, `jems`

is:

* **compact**: one source file and one header file

* **portable**: written in pure C (with C++ compatible headers)

* **deterministic**: `jems` uses user-provided data structures and never calls

`malloc()`.

* **yours to use**: `jems` is covered under the permissive MIT License.

`jems` derives much of its efficiency and small footprint by a philosophy of

trust: Rather than provide rigorous error checking of input parameters,

`jems` instead assumes that you provide valid parameters to function calls.

## A Short Example

`jems` has a "emit characters as you go" philosophy, which allows you to

generate huge JSON structures with minimal memory usage.  Here is a short

example:

```

#include "jems.h"

#include 

#include 

#define MAX_LEVEL 10  // how deeply nested the JSON structures can get

static jems_level_t jems_levels[MAX_LEVEL];

static jems_t jems;

static void write_char(char ch, uintptr_t arg) {

  fputc(ch, (FILE *)arg);

}

int main(void) {

    // initalize the jems object, using fputc() as the method for writing chars.

    jems_init(&jems, jems_levels, MAX_LEVEL, write_char, (uintptr_t)stdout);

    jems_object_open(&jems);       // start an object.

    jems_string(&jems, "colors");  // first object key is "colors"

    jems_array_open(&jems);        // first object value is an array

    jems_integer(&jems, 1);        // ... with three numbers

    jems_integer(&jems, 2);

    jems_integer(&jems, 3);

    jems_array_close(&jems);      // end of the array

    jems_string(&jems, "valid");  // second object key is "valid"

    jems_true(&jems);             // second object value is true

    jems_object_close(&jems);     // end of the object

}

```

This program will print

```

    {"colors":[1,2,3],"valid":true}

```

on the standard output.