1 /* Auto-reallocating array for arbitrary member types. */
2 /*
3  * Copyright (c) 2020 Neels Hofmeyr <neels@hofmeyr.de>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 /* Usage:
19  *
20  * ARRAYLIST(any_type_t) list;
21  * // OR
22  * typedef ARRAYLIST(any_type_t) any_type_list_t;
23  * any_type_list_t list;
24  *
25  * // pass the number of (at first unused) members to add on each realloc:
26  * ARRAYLIST_INIT(list, 128);
27  * any_type_t *x;
28  * while (bar) {
29  *         // This enlarges the allocated array as needed;
30  *         // list.head may change due to realloc:
31  *         ARRAYLIST_ADD(x, list);
32  *         if (!x)
33  *                 return ENOMEM; 
34  *         *x = random_foo_value;
35  * }
36  * for (i = 0; i < list.len; i++)
37  *         printf("%s", foo_to_str(list.head[i]));
38  * ARRAYLIST_FREE(list);
39  */
40 #define ARRAYLIST(MEMBER_TYPE) \
41 	struct { \
42 		MEMBER_TYPE *head; \
43 		MEMBER_TYPE *p; \
44 		unsigned int len; \
45 		unsigned int allocated; \
46 		unsigned int alloc_blocksize; \
47 	}
48 
49 #define ARRAYLIST_INIT(ARRAY_LIST, ALLOC_BLOCKSIZE) do { \
50 		(ARRAY_LIST).head = NULL; \
51 		(ARRAY_LIST).len = 0; \
52 		(ARRAY_LIST).allocated = 0; \
53 		(ARRAY_LIST).alloc_blocksize = ALLOC_BLOCKSIZE; \
54 	} while(0)
55 
56 #define ARRAYLIST_ADD(NEW_ITEM_P, ARRAY_LIST) do { \
57 		if ((ARRAY_LIST).len && !(ARRAY_LIST).allocated) { \
58 			NEW_ITEM_P = NULL; \
59 			break; \
60 		} \
61 		if ((ARRAY_LIST).head == NULL \
62 		    || (ARRAY_LIST).allocated < (ARRAY_LIST).len + 1) { \
63 			(ARRAY_LIST).p = recallocarray((ARRAY_LIST).head, \
64 				(ARRAY_LIST).len, \
65 				(ARRAY_LIST).allocated + \
66 				((ARRAY_LIST).allocated ? \
67 				(ARRAY_LIST).allocated / 2 : \
68 				(ARRAY_LIST).alloc_blocksize ? : 8), \
69 				sizeof(*(ARRAY_LIST).head)); \
70 			if ((ARRAY_LIST).p == NULL) { \
71 				NEW_ITEM_P = NULL; \
72 				break; \
73 			} \
74 			(ARRAY_LIST).allocated += \
75 				(ARRAY_LIST).allocated ? \
76 				(ARRAY_LIST).allocated / 2 : \
77 				(ARRAY_LIST).alloc_blocksize ? : 8, \
78 			(ARRAY_LIST).head = (ARRAY_LIST).p; \
79 			(ARRAY_LIST).p = NULL; \
80 		}; \
81 		if ((ARRAY_LIST).head == NULL \
82 		    || (ARRAY_LIST).allocated < (ARRAY_LIST).len + 1) { \
83 			NEW_ITEM_P = NULL; \
84 			break; \
85 		} \
86 		(NEW_ITEM_P) = &(ARRAY_LIST).head[(ARRAY_LIST).len]; \
87 		(ARRAY_LIST).len++; \
88 	} while (0)
89 
90 #define ARRAYLIST_INSERT(NEW_ITEM_P, ARRAY_LIST, AT_IDX) do { \
91 		int _at_idx = (AT_IDX); \
92 		ARRAYLIST_ADD(NEW_ITEM_P, ARRAY_LIST); \
93 		if ((NEW_ITEM_P) \
94 		    && _at_idx >= 0 \
95 		    && _at_idx < (ARRAY_LIST).len) { \
96 			memmove(&(ARRAY_LIST).head[_at_idx + 1], \
97 				&(ARRAY_LIST).head[_at_idx], \
98 				((ARRAY_LIST).len - 1 - _at_idx) \
99 					* sizeof(*(ARRAY_LIST).head)); \
100 			(NEW_ITEM_P) = &(ARRAY_LIST).head[_at_idx]; \
101 		}; \
102 	} while (0)
103 
104 #define ARRAYLIST_CLEAR(ARRAY_LIST) \
105 	(ARRAY_LIST).len = 0
106 
107 #define ARRAYLIST_FREE(ARRAY_LIST) \
108 	do { \
109 		if ((ARRAY_LIST).head && (ARRAY_LIST).allocated) \
110 			free((ARRAY_LIST).head); \
111 		ARRAYLIST_INIT(ARRAY_LIST, (ARRAY_LIST).alloc_blocksize); \
112 	} while(0)
113 
114 #define ARRAYLIST_FOREACH(ITEM_P, ARRAY_LIST) \
115 	for ((ITEM_P) = (ARRAY_LIST).head; \
116 	     (ITEM_P) - (ARRAY_LIST).head < (ARRAY_LIST).len; \
117 	     (ITEM_P)++)
118 
119 #define ARRAYLIST_IDX(ITEM_P, ARRAY_LIST) ((ITEM_P) - (ARRAY_LIST).head)