coreJSON Library

A parser strictly enforcing the ECMA-404 JSON standard, suitable for microcontrollers

Reference example

#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 (e.g. .). In the example above, bar has the value {"foo":"xyz"}. Therefore, a search for query key bar.foo would output xyz.

Building coreJSON

A compiler that supports C89 or later such as gcc is required to build the library.

For instance, if the example above is copied to a file named example.c, gcc can be used like so:

gcc -I source/include example.c source/core_json.c -o example
./example

gcc can also produce an output file to be linked:

gcc -I source/include -c source/core_json.c

Generating documentation

The Doxygen references were created using Doxygen version 1.8.20. To generate the Doxygen pages, please run the following command from the root of this repository:

doxygen docs/doxygen/config.doxyfile

Building unit tests

Platform Prerequisites

• For running unit tests
  • C90 compiler like gcc
  • CMake 3.13.0 or later
  • Ruby 2.0.0 or later is additionally required for the CMock test framework (that we use).
• For running the coverage target, gcov is additionally required.

Steps to build Unit Tests

1. Go to the root directory of this repository.

2. Create build directory: mkdir build && cd build

3. Run cmake while inside build directory: cmake -S ../test

4. Run this command to build the library and unit tests: make all

5. The generated test executables will be present in build/bin/tests folder.

6. Run ctest to execute all tests and view the test run summary.