#include <stdio.h>
#include <xfn/xfn.h>
/*
 This routine modifies an attribute associated
 with the named object. The modify operation supported are:
 	FN_ATTR_OP_ADD
 FN_ATTR_OP_ADD_EXCLUSIVE
 FN_ATTR_OP_REMOVE
 FN_ATTR_OP_ADD_VALUES
 FN_ATTR_OP_REMOVE_VALUES
 The function assumes the attribute values to be strings.
 Examples of using the function:
 The following function add an attribute of identifier "realname"
 with value "James Smith" to the user object "user/jsmith".
 	fns_attr_modify(
		"user/jsmith",
		"realname",
		"James Smith",
		FN_ATTR_OP_ADD);
 The following function removes an attribute of identifier 
 "location" from the printer object 
 "thisorgunit/service/printer/color".
 	fns_attr_modify(
		"thisorgunit/service/printer/color",
		"location",
		NULL,
		FN_ATTR_OP_REMOVE);
*/
static const char *attr_id_syntax = "fn_attr_syntax_ascii";
void fns_attr_modify(const char *name,
	const char *attr_id,
	const char *attr_value,
	unsigned int operation)
{
	FN_composite_name_t *name_comp;
	FN_identifier_t identifier, syntax;
	FN_attrvalue_t *values;
	FN_attribute_t *attribute;
	FN_status_t *status;
	FN_ctx_t *initial_context;
	name_comp = fn_composite_name_from_str((unsigned char *) name);
	status = fn_status_create();
	/* Obtain the initial context */
	initial_context = fn_ctx_handle_from_initial(0, status);
	if (!fn_status_is_success(status)) {
		fprintf(stderr, "Unable to obtain intial context\n");
		return;
	}
	/* Create the attribute to be added */
	/* First, the identifier */
	identifier.format = FN_ID_STRING;
	identifier.length = strlen(attr_id);
	identifier.contents = (void *) strdup(attr_id);
	/* Second, the syntax */
	syntax.format = FN_ID_STRING;
	syntax.length = strlen(attr_id_syntax);
	syntax.contents = (void *) strdup(attr_id_syntax);
	/* Third, the attribute value */
	if (attr_value) {
		values = (FN_attrvalue_t *) malloc(sizeof(FN_attrvalue_t));
		values->length = strlen(attr_value);
		values->contents = (void *) strdup(attr_value);
	} else
		values = NULL;
	/* Fourth, create the attribute */
	attribute = fn_attribute_create(&identifier, &syntax);
	/*Fifth, add the attribute value */
	if (values)
		fn_attribute_add(attribute, values, 0);
	
	/* Perform the XFN operation */
	fn_attr_modify(initial_context, name_comp, operation, attribute, 0,
status);
	if (!fn_status_is_success(status))
		fprintf(stderr, "Unable to perform attribute operation\n");
	fn_ctx_destroy(initial_context);
	fn_status_destroy(status);
	fn_composite_name_destroy(name_comp);
	fn_attibute_destroy(attribute);
	free(identifier.contents);
	free(syntax.contents);
	if (values) {
		free(values->contents);
		free(values);
 ]
]