oldiob / c-json

Complete Json parser/lexer with data types.

C-Json

This is intend to be a library designed to provide total control over JSON data structure in C.

Status

This project is currently done for me. I have nothing more to add. Although, no unit tests were made because I’m lazy, registering new tests is straigh forward and quick, see the Testing section for more info on that. That being said, I might add some tests in a distant future, if needed.

Data Structure

C-Json provides 3 data structures. JSON_Type, JSON_Dict and JSON_List. For every structures, many useful functions are provided to ensure speed and security of data manipulation. See the documentation for more info.

Parser

C-Json implements a parser generated by GNU Bison. This parser can parse any file descriptor that contain valid JSON data. It can either parse a global list or a global dictionary.

I/O

C-Json provides basic IO operations on its data structures. See the documentaion for more info.

Dependency

You will need to have GNU Bison in order to be able to compile the library. There’s no need to have flex, because the lexer is implemented by hand.

Build

To build the library, execute the following commands in a terminal.

$ autorefonf -i
$ ./configure
$ make

Install

To install the library, execute the following command in a terminal.

$ sudo make install

Testing

To create new tests, create a file under tests/inc. That file should be name test-[name].h and write your tests. In order to execute the tests, you have to include your file in test-to-include.h under the header Includes Tests. After that, use the macro TEST and pass as parameter the name of your function in the list variable tests. Your test is now register as a worker that will have his own thread when tests are executed.

Your test should have the following prototype:

void* My_Test(void*)

The parameter is the adress of a struct JSON_WorkerArg that can be pass in the TEST macro during registation. The return value is the adress of a struct JSON_WorkerRetVal. It should contain the status code of the test, i.e if it has succeed or not, the name of the test and a buffer containing useful information to display.

Useful Macros

TEST(NAME, …)

Register a test named NAME with (…) args.

INIT_WORKER(PTR, NAME, BUFF, OK)

Initiliaze a JSON_WorkerRetVal.

Many more useful macros can be found under inc/utils.h.

Example

// test-foo.h
(...)

void* My_Test(void*)
{
  /*
   * Name: "Foo Test"
   * Buff: "\0"
   * Ok  : 1
   */
  INIT_WORKER(val, "Foo Test", "\0", 1);
  
  return val;
}

(...)

// test-to-include.h
(...)

/*=============================================================================+
|                               Includes Tests                                |
+=============================================================================*/
#include "test-list.h"
#include "test-foo.h"  // Here we include our test.

JSON_Testers test[] =
{
  (...),
  TEST(My_Test), // We register one of our test here.
  {NULL}         // Very important, last test should always be NULL.
 };

 (...)

Documentation

The documentation is generated by Doxygen. To generate the documentation, run *make doc*.

Usage

#include <JSON/json.h>   // Main json structure
#include <JSON/parser.h> // Bison parser
#include <JSON/io.h>     // io manipulaation

#define DICT_SIZE 64
#define LIST_SIZE 128

size_t hashType(const char* key);

int main(int argc, char* argv[])
{
  JSON_Type* type = NULL;

  FILE* in = fopen(argv[1], "r");

  ////////////////////////////////////////////////////////////////////////////
  // The parser need the following arguments:
  // 1. A pointer to pointer of JSON_Type that will store the overall parsing
  // 2. A file descriptor to read from
  // 3. A hash function that will hash value for JSON_Dict structures
  // 4. The number of buckets for JSON_Dict structures during parsing
  // 5. The initial size of JSON_List structures during parsing
  ////////////////////////////////////////////////////////////////////////////
  if (in)
    JSON_parse(&type, in, &hashType, DICT_SIZE, LIST_SIZE);

  fclose(in);

  if (!type)
    return 1;

  JSON_PrintType(type, stdout);
  // Do stuff with type here

  JSON_FreeType(type);

  fclose(out);

  return 0;
}

/*  Primitive hash function  */
size_t hashType(JSON_HashKey key)
{
  size_t hash = 0;

  while (*key)
    hash += (size_t)(*(key++));

  return hash;
}