## coreJSON Library

This repository contains the coreJSON library, a parser that strictly enforces the ECMA-404 JSON standard and is suitable for low memory footprint embedded devices. The coreJSON library is distributed under the [MIT Open Source License](LICENSE).

This library has gone through code quality checks including verification that no function has a [GNU Complexity](https://www.gnu.org/software/complexity/manual/complexity.html) score over 8, and checks against deviations from mandatory rules in the [MISRA coding standard](https://www.misra.org.uk). Deviations from the MISRA C:2012 guidelines are documented under [MISRA Deviations](MISRA.md). This library has also undergone both static code analysis from [Coverity static analysis](https://scan.coverity.com/), and validation of memory safety through the [CBMC automated reasoning tool](https://www.cprover.org/cbmc/).

See memory requirements for this library [here](./docs/doxygen/include/size_table.md).

**coreJSON v3.2.0 [source code](https://github.com/FreeRTOS/coreJSON/tree/v3.2.0/source) is part of the [FreeRTOS 202210.00 LTS](https://github.com/FreeRTOS/FreeRTOS-LTS/tree/202210.00-LTS) release.**

**coreJSON v3.0.0 [source code](https://github.com/FreeRTOS/coreJSON/tree/v3.0.0/source) is part of the [FreeRTOS 202012.00 LTS](https://github.com/FreeRTOS/FreeRTOS-LTS/tree/202012.00-LTS) release.**

## Reference example

```c
#include <stdio.h>
#include "core_json.h"

int main()
{
    // Variables used in this example.
    JSONStatus_t result;
    char buffer[] = "{\"foo\":\"abc\",\"bar\":{\"foo\":\"xyz\"}}";
    size_t bufferLength = sizeof( buffer ) - 1;
    char queryKey[] = "bar.foo";
    size_t queryKeyLength = sizeof( queryKey ) - 1;
    char * value;
    size_t valueLength;
    
    // Calling JSON_Validate() is not necessary if the document is guaranteed to be valid.
    result = JSON_Validate( buffer, bufferLength );
    
    if( result == JSONSuccess )
    {
        result = JSON_Search( buffer, bufferLength, queryKey, queryKeyLength,
                              &value, &valueLength );
    }
    
    if( result == JSONSuccess )
    {
        // The pointer "value" will point to a location in the "buffer".
        char save = value[ valueLength ];
        // After saving the character, set it to a null byte for printing.
        value[ valueLength ] = '\0';
        // "Found: bar.foo -> xyz" will be printed.
        printf( "Found: %s -> %s\n", queryKey, value );
        // Restore the original character.
        value[ valueLength ] = save;
    }

    return 0;
}
```
A search may descend through nested objects when the `queryKey` contains matching key strings joined by a separator, `.`. In the example above, `bar` has the value `{"foo":"xyz"}`. Therefore, a search for query key `bar.foo` would output `xyz`.

## Documentation

For pre-generated documentation, please see the documentation linked in the locations below:

| Location |
| :-: |
| [FreeRTOS.org](https://freertos.org/Documentation/api-ref/coreJSON/docs/doxygen/output/html/index.html) |

Note that the latest included version of the coreJSON library may differ across repositories.