README

/*
Copyright (c) 2014 xphh

Permission is hereby granted, free of charge, to any person obtaining a copy
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furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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SOFTWARE.
*/

Welcome to cobj.

==============================
	What's cobj?
==============================
cobj is a simple implementation of C object with reflection function, which 
is very common in Java. An object defined by cobj's rules can easily convert 
to/from Json string automatically.

The source code of cobj project is brief, which contains:
cobj.h           --- header file of cobj
cobj.c           --- implementation
test.c           --- test code for demo
cJSON/           --- cJSON directory
	cJSON.h
	cJSON.c

You can add cobj.h and cobj.c files into your project directly as you wish.
Also if you just want to compile and test cobj only, build like this:
	gcc cobj.c test.c cJSON/cJSON.c -o test -lm
and run test:
	./test

==============================
	Things you must know!
==============================
As you have seen before, cobj is rely on cJSON to convert between objects and
Json strings. cobj project already contains cJSON source code in cJSON directory,
but you might prefer the latest version of cJSON, just visit here:
	http://sourceforge.net/projects/cjson/

The first thing you need to know is that cobj makes the rules for defining an 
object. The object must be defined as cobj need, or it cannot be convert 
to/from Json string automatically. You can learn it in 'How to use' chapter.

A cobj-need object is only support a few data types now, which are listed below:
	int                   --- integer
	BOOL                  --- boolean, typedef from int
	CSTR                  --- const string, defined in cobj
	struct                --- custom-declared structure
	DECALRE_LIST(int)     --- array list of int
	DECALRE_LIST(CSTR)    --- array list of CSTR
	DECALRE_LIST(struct)  --- array list of struct
	
cobj provides two custom types for use:

CSTR --- Actually it is a struct contains a char pointer.
         To initialize a CSTR, use 'CS' macro: CSTR s = CS("hello word");
         To delete a CSTR, use 'CS_CLEAR' macro: CS_CLEAR(s);
         or memory leak might occur.
		 
list --- Define with 'DECALRE_LIST' macro, can be generic.
         To initialize a list, use 'LIST_INIT' macro.
         To delete a list, use 'LIST_CLEAR' macro.
         Before deleting a list, make sure you have freed the items inside.
         For more details, please read cobj.h.

==============================
	How to use cobj?
==============================
The way to make C object with reflection function possible is to adhere an 
additional 'metainfo' to this object. A metainfo saves the hierarchy 
information of an object's structure. Therefore you need to declare object's
structure and metainfo at the same time.

metainfo must be defined in .c files, start with 'DEFINE_METAINFO' macro.

Think a structure declared like this:
	struct BigBox
	{
		int pen;
		CSTR text;
	}
Then the corresponding metainfo is like this:
	DEFINE_METAINFO(BigBox)
	{
		// must create it on first line
		METAINFO_CREATE(BigBox);
		// add members, the parameters are: 
		// (structure name, member data type, member name)
		METAINFO_ADD_MEMBER(BigBox, FIELD_TYPE_INT, pen);
		METAINFO_ADD_MEMBER(BigBox, FIELD_TYPE_CSTR, text);
	}
	
Structure can nest structure if like this:
	struct BigBox
	{
		struct SmallBox
		{
			int pen;
			CSTR text;
		} sb;
	}
which metainfo is like this:
	DEFINE_METAINFO(BigBox)
	{
		// must create it on first line
		METAINFO_CREATE(BigBox);
		// 'SmallBox' begin, the parameters are: 
		// (outer structure name, inner structure name, member name)
		METAINFO_CHILD_BEGIN(BigBox, SmallBox, sb);
			// add members
			METAINFO_ADD_MEMBER(SmallBox, FIELD_TYPE_INT, pen);
			METAINFO_ADD_MEMBER(SmallBox, FIELD_TYPE_CSTR, text);
		// 'SmallBox' end
		METAINFO_CHILD_END();
	}

In many cases, we need define a list, think about this:
 	struct BigBox
	{
		DECLARE_LIST(int) penList;
		DECLARE_LIST(struct SmallBox
		{
			int pen;
			CSTR text;
		}) sbList;
	}
which metainfo is like this:
	DEFINE_METAINFO(BigBox)
	{
		// must create it on first line
		METAINFO_CREATE(BigBox);
		// add a member as list, the parameters are the same.
		METAINFO_ADD_MEMBER_LIST(BigBox, FIELD_TYPE_INT, penList);
		// 'SmallBox' list begin, the parameters are the same. 
		METAINFO_CHILD_LIST_BEGIN(BigBox, SmallBox, sbList);
			// add members
			METAINFO_ADD_MEMBER(SmallBox, FIELD_TYPE_INT, pen);
			METAINFO_ADD_MEMBER(SmallBox, FIELD_TYPE_CSTR, text);
		// 'SmallBox' end, the same.
		METAINFO_CHILD_END();
	}
	
After metainfo created, you must register it at the beginning of your program:
	REGISTER_METAINFO(BigBox);
	
At this point, the prepare works are done. 

To new an object from a struct('s' for name), will return a pointer:
	OBJECT_NEW(s)
To delete an object(point to ptr) and free all memories inside:
	OBJECT_DELETE(ptr, s)
To convert an object('s' for object's struct name) to a json string:
	OBJECT_TO_JSON(ptr, s)
To convert from a json string('str'), will return a pointer to object of s:
	OBJECT_FROM_JSON(s, str)
	
Want to learn more? Please read and run test.c.

==============================
	About author
==============================
cobj is written by xphh(Ping Xu), lived in Hangzhou, China.
Bug report and communication, please send E-mail: netten2005@163.com