/*****************************************************************************
function for allocating a 2d array 
******************************************************************************
Input:
d1		first dimension
d2		second dimension
size		size of each array element

Output:	pointer to the array
*****************************************************************************/
void **alloc2d( int d1, int d2, int size) {
	int i,j;
	void **p;
	p = (void**)malloc(d1*sizeof(void*));

	if ( p == NULL ) return NULL;
	for ( i=0; i<d1; ++i ) {
		p[i] = malloc(d2*size);
		if ( p[i] == NULL ) return NULL;
	}
	return p;
}
/*****************************************************************************
function for freeing a 2d array 
******************************************************************************
Input:
p		pointer to the array
d1		first dimension
d2		second dimension
*****************************************************************************/
void free2d( void **p, int d1, int d2 ) {
	int i,j;

	if ( p != NULL ) {
		for ( i=0; i<d1; ++i ) {
			if ( p[i] != NULL )
				free(p[i]);
		}
		free(p);
	}
}