Thread: Generic Pointers to structures

I have a problem in handling pointers to structures:

I have an XML as below:
<ROOTNODE>
<NAME>
<ADDRESS>
<PHONE>
<EMAIL>
<DATE>

<SubBranch>
<NAME>
<ADDRESS>
<PHONE>
<EMAIL>
<DATE>
</SubBranch>

</ROOTNODE>

I am parsing the XML and populating it into a structure.The structure is:

Code:

typedef struct 
{
	char Name[20];
	char Address[20];
	char Phone[20];
	char Email[20];
	SUBBRANCH     stBranch[10];    
}MAINBRANCH;

typedef struct 
{
	char Name[20];
	char Address[20];
	char Phone[20];
	char Email[20];
}SUBBRANCH ;

Since the data inside the <ROOTNODE> and that inside the <SubBranch> is repeated, I want to write a single functions which will parse the data and put it into the corresponding structure.

How would I pass a generic pointer to a structure into a function? Below is the generic function I am trying: Here I am passing the pointer to MAINBRANCH structure and in the function I am typecasting it accordingly.

Code:

// Passing the pointer to the main structure and an indicator to the function 
GetDataFromXML(MAINBRANCH *structptr , int i) 
{
	void *temp;  //Declaring a void pointer to handle the incoming structure
	if(i == 0)   // i =0 for root data
	{	temp = MAINBRANCH;
               //Parse data and populate into MAINBRANCH
        }
	else if (i == 1)  // i =1 for branch data
	{
		temp = MAINBRANCH.SUBBRANCH;
               //Parse and populate into SUBBRANCH
	}
	
}

Please suggest how I can implement this requirement.

So, if I understand you right then you want to pass a void pointer to GetDataFromXML, with 'i' identifying its type, then act accordingly within the function. Something like this maybe:

Code:

//call casts to void to send it into function
GetDataFromXML((void*)myMainbranchStructPtr, 0);

//definition converts void pointer to correct type
GetDataFromXML(void* structptr , int i) 
{
	if(i == 0)   // i =0 for root data
	{	MAINBRANCH* ptr = (MAINBRANCH*)structptr;
               //Parse data and populate into MAINBRANCH
        }
	else if (i == 1)  // i =1 for branch data
	{
		SUBBRANCH* ptr = (SUBBRANCH*)structptr;
               //Parse and populate into SUBBRANCH
	}
	
}

Havent tested it, but I think thats more or less right.

Thanks mike_g for the help.

neandrake,
This is not the actual XML I am working on. I just posted this for it to look simple. The basic idea I needed , was to process similar set of tags that are in different places in the XML FILe, into different structures using a single common function.

I didnt know how to pass different structure pointers to a single function.


My document contains more than a hundred tags whose values I need to populate. Going by salem's advice, I would then have to create more than a hundred strings/Name-Value pairs for every XML I have. Is this a good programming practice( However it does make things simple)?