/*
**  Written by David Gerdes  US Army Construction Engineering Research Lab
**  	April 1992
**  Copyright 1992 USA-CERL   All rights reserved.
**
*/


/*
**  read from stdin and each line into a linked list of chars
**  then print it back out.   if there is any argument specified
**  the lines will be printed out reversed.
*/

#include <stdio.h>
#include <grass/linkm.h>

struct link {
    char let;
    struct link *next;
};

int 
main (int argc, char *argv[])
{
    register int i;
    VOID_T *head;
    struct link List, *tmp, *p;
    int rev = 0;
    char buf[4096];

    if (argc == 2)
	rev = 1;


    List.next = NULL;
    List.let = ' ';
    

    link_set_chunk_size (1);
    head = (VOID_T *) link_init (sizeof (struct link));


    while (NULL != gets (buf))
    {
	for (i = 0 ; buf[i] != '\0' ; i++)
	{
	    tmp = (struct link *) link_new (head);
	    tmp->let = buf[i];
	    if (rev)
		add_link_rev (&List, tmp);
	    else
		add_link (&List, tmp);
	}

	dumplist (&List);

	p = List.next;

	while (p != NULL && p->next != NULL)
	{
	    tmp = p->next;
	    link_dispose (head, p);
	    p = tmp;
	}
	List.next = NULL;
    }

    link_cleanup (head);

    exit (0);
}

int 
add_link_rev (struct link *List, struct link *link)
{
    struct link *p;

    p = List->next;
    List->next = link;
    link->next = p;
}

int 
add_link (struct link *List, struct link *link)
{
    struct link *p;

    p = List;
    while (p->next != NULL)
	p = p->next;
    p->next = link;
    link->next = NULL;
}

int 
dumplist (struct link *List)
{
    struct link *p;

    p = List->next;
    while (p != NULL)
    {
	putchar (p->let);
	p = p->next;
    }
    putchar ('\n');
}