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Json serialization support [message #35353]

Sat, 04 February 2012 21:15

Mindtraveller
Messages: 917
Registered: August 2007
Location: Russia, Moscow rgn.

Experienced Contributor

Since Mirek announced "native" JSON support in U++, I tried to use it for serializing my structures and found it to be relatively hard to implement. For example, loading not-very-complex JSON led me to following ugly code:

		for (int projectI=0; projectI<versions.GetCount(); ++projectI)
		{
			if (!IsValueMap(versions[projectI]))
				continue;
			
			ValueMap curProject(versions[projectI]);

			ValueMap curProjectGlobal;
			if (IsValueMap(curProject[KEY_PROJECT_GLOBAL]))
				curProjectGlobal = curProject[KEY_PROJECT_GLOBAL];
			if (!IsDate(curProjectGlobal[KEY_PROJECT_GLOBAL_DATE]))
				curProjectGlobal.Set(KEY_PROJECT_GLOBAL_DATE, GetSysDate());
			if (!IsNumber(curProjectGlobal[KEY_PROJECT_GLOBAL_COUNTER]))
				curProjectGlobal.Set(KEY_PROJECT_GLOBAL_COUNTER, 0);
			curProject.Set(KEY_PROJECT_GLOBAL, curProjectGlobal);
			
			ValueMap curProjectVersion;
			if (IsValueMap(curProject[KEY_PROJECT_VERSION]))
				curProjectVersion = curProject[KEY_PROJECT_VERSION];
			if (!IsDate(curProjectVersion[KEY_PROJECT_VERSION_DATE]))
				curProjectVersion.Set(KEY_PROJECT_VERSION_DATE, GetSysDate());
			if (!IsNumber(curProjectVersion[KEY_PROJECT_VERSION_COUNTER]))
				curProjectVersion.Set(KEY_PROJECT_VERSION_COUNTER, 0);
			ValueMap curProjectVersionCurrent;
			if (IsValueMap(curProjectVersion[KEY_PROJECT_VERSION_CURRENT]))
				curProjectVersionCurrent = curProjectVersion[KEY_PROJECT_VERSION_CURRENT];
			curProjectVersion.Set(KEY_PROJECT_VERSION_CURRENT, curProjectVersionCurrent);

			curProject.Set(KEY_PROJECT_VERSION, curProjectVersion);
			
			versions.SetAt(projectI, curProject);
		}

Maybe ValueMap and ValueArray classes are good for other tasks, anyway.
So I thought about little extending JSON support in U++ making it the same as serialization with Stream and Xml - as IMO it was a brilliant solution to make it pure and clear inside a single member function (I mean Serialize and Xmlize).

After a day of work I've made a number of helper classes based on CParser (and inspired with Mirek's JSON parsing functions).
Finally, I've come to what I wanted:

struct TestStruct2
{
	int c;
	bool d;
	double e;
	Time   t;
	
	void Jsonize(JsonIO &json)
	{
		json
			("c", c)
			("d", d)
			("e", e)
			("t", t)
		;
	}
};
struct TestStruct
{
	String u;
	String a;
	int    b;
	TestStruct2 c;
	VectorMap<String, Vector<int> > map1;
	
	void Jsonize(JsonIO &json)
	{
		json
			("a",a)
			("b",b)
			("c",c)
			("u",u)
			("map1",map1)
		;
	}
};

As you can see, JSON serialization is used the common way. Also it natively supports VectorMap/ArrayMap and Vector/Array serialization.

The code was not widely tested and not all the types are supported, but this is the beginning.

Also the efficiency of different serialization types was tested.
JSON/XML/BINARY timing:
release: 125/265/16
debug: 842/1857/125
Maybe, not that bad for 1-day code which was not optimized at all.

So here are sources with Jsonize package. If it is compiled as a main package (not as dependency), the test binary is made.

Any comments, critics and suggestions are welcome.

Attachment: Jsonize.zip
(Size: 3.48KB, Downloaded 296 times)

[Updated on: Sun, 05 February 2012 14:58]

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