#include "apue.h"

#define	MAXARGC		50	/* max number of arguments in buf */
#define	WHITE	" \t\n"	/* white space for tokenizing arguments */

/*
 * buf[] contains white-space-separated arguments.  We convert it to an
 * argv-style array of pointers, and call the user's function (optfunc)
 * to process the array.  We return -1 if there's a problem parsing buf,
 * else we return whatever optfunc() returns.  Note that user's buf[]
 * array is modified (nulls placed after each token).
 */
int
buf_args(char *buf, int (*optfunc)(int, char **))
{
	char	*ptr, *argv[MAXARGC];
	int		argc;

	if (strtok(buf, WHITE) == NULL)		/* an argv[0] is required */
		return(-1);
	argv[argc = 0] = buf;
	while ((ptr = strtok(NULL, WHITE)) != NULL) {
		if (++argc >= MAXARGC-1)	/* -1 for room for NULL at end */
			return(-1);
		argv[argc] = ptr;
	}
	argv[++argc] = NULL;

	/*
	 * Since argv[] pointers point into the user's buf[],
	 * user's function can just copy the pointers, even
	 * though argv[] array will disappear on return.
	 */
	return((*optfunc)(argc, argv));
}