MyJSON

A C++ JSON library

What this library is not:

This library is not intended to fully replace other C++ JSON implementations.

So, why this library ?

The goal of this library was to solve two problems of other solutions I found:

• Data Reordering: Input order is kept.
• Memory Exhaustion: Tuples are immediatly flushed to disk.

Using

Just include the lib directory on your solution

Limitations

• No list support
• No nested entry support
• 5-entry-limited tuples
• Escapes only the slash character

Identation

Output JSON is idented based on the defined value of #define INITIAL_IDENT 0. No identation depth configuration is implemented yet.

Bugs

A lot, please report them.

Tests

A set of tests to check JsonWriter's working.

Instantiate

Just create and destroy the JsonWriter object:

JsonWriter *json = new JsonWriter(file.c_str());

Output:

{
}

Single.List.Single.Entry

Just a single entry:

json->add_to_entry("field 1","1","field 2","2","field 3","3","field 4","4","field 5","5");

Output:

{
	"Libs":
		[
		{
			"field 1":"1"
				,
				"field 2":"2"
					,
				"field 3":"3"
					,
				"field 4":"4"
					,
				"field 5":"5"
		}
		]
}

Single.List.Single.Entry.NULL

Another single entry, without passing all arguments:

json->add_to_entry("field 1","1","field 2","2","field 3","3","","","","");

Output:

{
	"Libs":
		[
		{
				"field 1":"1"
				,
				"field 2":"2"
					,
				"field 3":"3"
		}
		]
}

Single.List.Multiple.Entry

Adding more entries to the previous examples:

	json->add_to_entry("field 1","1","field 2","2","field 3","3","field 4","4","field 5","5");
	json->add_to_entry("field 1","10","field 2","20","field 3","30","field 4","40","field 5","50");

Output:

{
	"Libs":
		[
		{
			"field 1":"1"
			,
			"field 2":"2"
			,
			"field 3":"3"
			,
			"field 4":"4"
			,
			"field 5":"5"
		}
	,
		{
			"field 1":"10"
			,
			"field 2":"20"
			,
			"field 3":"30"
			,
			"field 4":"40"
			,
			"field 5":"50"
		}
	]
}

Multiple.List.Single.Entry

Adding data on a higher entry:

	json->add_entry(entry);
	json->add_to_entry("field 1","1","field 2","2","field 3","3","field 4","4","field 5","5");
	json->add_entry(entry2);
	json->add_to_entry("field 1","10","field 2","20","field 3","30","field 4","40","field 5","50");

Output:

{
	"Libs":
		[
		{
			"field 1":"1"
				,
				"field 2":"2"
					,
				"field 3":"3"
					,
				"field 4":"4"
					,
				"field 5":"5"
		}
		]
	,
	"Bins":
		[
		{
			"field 1":"10"
				,
			"field 2":"20"
				,
			"field 3":"30"
				,
			"field 4":"40"
				,
			"field 5":"50"
		}
		]
}

Multiple.List.Multiple.Entry

The most complete example:

	json->add_entry(entry);
	json->add_to_entry("field 1","1","field 2","2","field 3","3","field 4","4","field 5","5");
	json->add_to_entry("field 1","1","field 2","2","field 3","3","field 4","4","field 5","5");
	json->add_entry(entry2);
	json->add_to_entry("field 1","10","field 2","20","field 3","30","field 4","40","field 5","50");
	json->add_to_entry("field 1","10","field 2","20","field 3","30","field 4","40","field 5","50");
	json->add_to_entry("field 1","10","field 2","20","field 3","30","field 4","40","field 5","50");

Output:

{
	"Libs":
		[
		{
			"field 1":"1"
				,
				"field 2":"2"
					,
				"field 3":"3"
					,
				"field 4":"4"
					,
				"field 5":"5"
		}
	,
		{
			"field 1":"1"
				,
			"field 2":"2"
				,
			"field 3":"3"
				,
			"field 4":"4"
				,
			"field 5":"5"
		}
	]
		,
		"Bins":
			[
			{
				"field 1":"10"
					,
				"field 2":"20"
					,
				"field 3":"30"
					,
				"field 4":"40"
					,
				"field 5":"50"
			}
	,
		{
			"field 1":"10"
				,
			"field 2":"20"
				,
			"field 3":"30"
				,
			"field 4":"40"
				,
			"field 5":"50"
		}
	,
		{
			"field 1":"10"
				,
			"field 2":"20"
				,
			"field 3":"30"
				,
			"field 4":"40"
				,
			"field 5":"50"
		}
	]
}

Usage Example

Consider the following input:

{
	"Movies":
	[
		{
			"title":"A New Hope",
			"year":"1977"
		},
		{
			"title":"The Empire Strikes Back",
			"year":"1980"
		},
		{
			"title":"Return of the Jedi",
			"year":"1983"
		}
	]
}

It can be parsed by the following python code:

f = open(sys.argv[1],"r").read()
l = json.loads(f)

for entries in l['Movies']:
	print("Title",entries['title'])
	print("Year",entries['year'])

The following output is generated:

('Title', u'A New Hope')
('Year', u'1977')
('Title', u'The Empire Strikes Back')
('Year', u'1980')
('Title', u'Return of the Jedi')
('Year', u'1983')