1 /*
2  * Functions for dealing with linked lists of goodies
3  * Functions with names starting with an "_" have compainion #defines
4  * in rogue.h which take the address of the first argument and pass it on.
5  *
6  * list.c	1.4 (A.I. Design) 12/5/85
7  */
8 
9 #include "rogue.h"
10 #include "curses.h"
11 
12 extern THING *_things;
13 extern int   *_t_alloc;
14 /*
15  * detach:
16  *	Takes an item out of whatever linked list it might be in
17  */
18 _detach(list, item)
19 register THING **list, *item;
20 {
21     if (*list == item)
22 	*list = next(item);
23     if (prev(item) != NULL) item->l_prev->l_next = next(item);
24     if (next(item) != NULL) item->l_next->l_prev = prev(item);
25     item->l_next = NULL;
26     item->l_prev = NULL;
27 }
28 
29 /*
30  * _attach:
31  *	add an item to the head of a list
32  */
33 _attach(list, item)
34 register THING **list, *item;
35 {
36     if (*list != NULL)
37     {
38 	item->l_next = *list;
39 	(*list)->l_prev = item;
40 	item->l_prev = NULL;
41     }
42     else
43     {
44 	item->l_next = NULL;
45 	item->l_prev = NULL;
46     }
47     *list = item;
48 }
49 
50 /*
51  * _free_list:
52  *	Throw the whole blamed thing away
53  */
54 _free_list(ptr)
55 register THING **ptr;
56 {
57     register THING *item;
58 
59     while (*ptr != NULL)
60     {
61 	item = *ptr;
62 	*ptr = next(item);
63 	discard(item);
64     }
65 }
66 
67 
68 /*
69  * new_item
70  *	Get a new item with a specified size
71  */
72 THING *
73 new_item()
74 {
75     register THING *item;
76 #ifdef DEBUG
77     if ((item = (THING *) talloc()) == NULL)
78 	    if (me())msg("no more things!");
79 	else
80 #else
81     if ((item = (THING *) talloc()) != NULL)
82 #endif DEBUG
83              item->l_next = item->l_prev = NULL;
84     return item;
85 }
86 
87 /*
88  * talloc: simple allocation of a THING
89  */
90 talloc()
91 {
92     register int i;
93 
94     for (i=0;i<MAXITEMS;i++)
95     {
96     	if (_t_alloc[i] == 0)
97     	{
98     	    if (++total > maxitems)
99     		maxitems = total;
100     	    _t_alloc[i]++;
101     	    setmem(&_things[i],sizeof(THING),0);
102     	    return &_things[i];
103     	}
104     }
105     return NULL;
106 }
107 
108 /*
109  * discard:
110  *	Free up an item
111  */
112 discard(item)
113 register THING *item;
114 {
115     register int i;
116 
117     for (i=0;i<MAXITEMS;i++)
118     {
119     	if (item == &_things[i])
120     	{
121     	    --total;
122     	    _t_alloc[i] = 0;
123     	    return 1;
124     	}
125     }
126     return NULL;
127 }
128 ÿ