Purpose:

I am doing a modularization work on a C project. It is hard to do a perfect design in the beginning. A resonable method is try many times to find the right one. This also means we will have a lot of coding work to do. Consider that valueble work is design not coding. So I want using tool to do some coding work. This tool is uesd to do code replacing work. If you konw any other tool like this, please let me konw.

Principle:

According C program language gramma.
Use reguler experssion to find the right position and replace target.

Example:

Demo project is following:

	typedef struct{
		int data;
	}t_data;

	typedef struct{
		int index; //a container maybe have many element, use this to indicate unify ID
	#ifndef IMPROVE
		int data;
	#else
		t_data _data;
	#endif
	} t_struct;


	t_struct global_struct;

	original_demo_function()
	{
	  t_data *struct_variable = &global_struct;

	  struct_variable->data = 0x88; //set value operation (memory accessing)
	  int local_data = struct_variable->data;//get value operation (memory accessing)

Due to modularization, we should change memory accessing to via API.

processed_demo_function()
{
	t_data *struct_variable = &global_struct;

	struct_set_data_operation(struct_variable->index,0x88); //set value operation (API)
	int local_data = struct_get_data_operation(struct_variable->index); //get value operation (API)
}

Or we have to change struct define, in this case enable macro IMPROVE.

#ifdef IMPROVE
processed_demo_function()
	{
		t_data *struct_variable = &global_struct;

		struct_variable->_data.data = 0x88; //set value operation (data be replaced)
	    int local_data = struct_variable->_data.data;//get value operation (data be replaced)
	}

#endif

Usage:

In the example, we have 3 operation types set, get and replace(rep). Different operation use different replace processing.

For set in example is

   struct_variable->data = 0x88; => struct_set_data_operation(struct_variable->index,0x88);

   We replace "struct_variable->data = " to "struct_set_data_operation(struct_variable->index," and add ")" following the value.
   Thus "struct_variable->data = " is target in original file. "struct_set_data_operation(struct_variable->index," is substitute in final file.

For get in example is

  int local_data = struct_variable->data; => int local_data = struct_get_data_operation(struct_variable->index);

  We replace "struct_variable->data" to "struct_get_data_operation(struct_variable->index" and add ")" following the value.
  Thus "struct_variable->data" is target in original file. "struct_get_data_operation(struct_variable->index" is substitute in final file.

For rep in example is

  struct_variable->data = 0x88; => struct_variable->_data.data = 0x88;
  int local_data = struct_variable->data; => int local_data = struct_variable->_data.data;

  We replace "data" to "_data.data".
  Thus "data" is target in original file. "_data.data" is substitute in final file.

We can find out that we should tell tool what target bing replaced to what substitute with wich operation. We can record all work in a csv file with following format.

--op-- --target-- --substitute-- set "struct_variable->data = " "struct_set_data_operation(struct_variable->index," get "struct_variable->data" "struct_get_data_operation(struct_variable->index" rep "data" "_data.data"

Run command: In path of src, use python(above 3.5) run command: \c_source_code_replace\src>python c_sourceCode_replace.py mapping_file.csv test.c

Test result: @@ -21,6 +21,6 @@ original_demo_function() { t_data *struct_variable = &global_struct;

• struct_variable->data = 0x88; //set value operation
• int local_data = struct_variable->data;//get value operation

• struct_set_data_operation(struct_variable->index, 0x88) ; //set value operation
• int local_data = struct_get_data_operation(struct_variable->index);//get value operation }