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Using Arrays with Macros

Friday, July 1, 2005 by digitalpeer

Just playing around with the idea of array bounds checking by using macros in C instead of using void pointers and real code. While usable, I still can't get around the fact that it won't work everywhere.

#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

#define DECLARE_ARRAY(type,name,size) \
	extern type array_##name[size];
	
#define DEFINE_ARRAY(type,name,size) \
	static const int size_##name = size; \
	type array_##name[size];

#define ARRAY_INIT(name,value) \
	do { \
	memset(array_##name,value,size_##name * sizeof(array_##name)); \
	} while (0);

#define ARRAY_GET(name,index,result) \
	do { \
	assert(index >= 0 && index < size_##name && result); \
	*result = array_##name[index]; \
	} while (0);

#define ARRAY_SET(name,index,value) \
	do { \
	assert(index >= 0 && index < size_##name); \
	array_##name[index] = value; \
	} while (0);

#define ARRAY_SIZE(name) size_##name
	
DECLARE_ARRAY(int,myarray,5)
DEFINE_ARRAY(int,myarray,5)
	
int main()
{
	int value;
	int x;
	ARRAY_INIT(myarray,0)
	ARRAY_SET(myarray,0,1)
	ARRAY_SET(myarray,1,1)
	ARRAY_SET(myarray,2,5)
	ARRAY_SET(myarray,3,1)
	ARRAY_SET(myarray,4,1)
	
	for (x = 0; x < ARRAY_SIZE(myarray);x++)
	{
		ARRAY_GET(myarray,x,&value)
		printf("value: %d\n",value);
	}
	
	
	return 0;	
}