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 #pragma once
19 
20 #ifdef __linux__
21 /* stupid shims to compile and test on linux */
22 #include <strings.h>
23 static inline void *reallocarray(void *buf, size_t n, size_t member_size)
24 {
25 	return realloc(buf, n * member_size);
26 }
27 static inline void *recallocarray(void *buf, size_t oldn, size_t n, size_t member_size)
28 {
29 	buf = reallocarray(buf, n, member_size);
30 	bzero(((char*)buf) + (oldn * member_size), (n - oldn) * member_size);
31 	return buf;
32 }
33 #endif
34 
35 
36 /* Usage:
37  *
38  * ARRAYLIST(any_type_t) list;
39  * // OR
40  * typedef ARRAYLIST(any_type_t) any_type_list_t;
41  * any_type_list_t list;
42  *
43  * ARRAYLIST_INIT(list, 128); // < number of (at first unused) members to add on each realloc
44  * any_type_t *x;
45  * while (bar) {
46  *         ARRAYLIST_ADD(x, list); // < enlarges the allocated array as needed; list.head may change due to realloc
47  *         if (!x)
48  *                 abort();
49  *         *x = random_foo_value;
50  * }
51  * for (i = 0; i < list.len; i++)
52  *         printf("%s", foo_to_str(list.head[i]));
53  * ARRAYLIST_FREE(list);
54  */
55 #define ARRAYLIST(MEMBER_TYPE) \
56 	struct { \
57 		MEMBER_TYPE *head; \
58 		unsigned int len; \
59 		unsigned int allocated; \
60 		unsigned int alloc_blocksize; \
61 	}
62 
63 #define ARRAYLIST_INIT(ARRAY_LIST, ALLOC_BLOCKSIZE) do { \
64 		(ARRAY_LIST).head = NULL; \
65 		(ARRAY_LIST).len = 0; \
66 		(ARRAY_LIST).allocated = 0; \
67 		(ARRAY_LIST).alloc_blocksize = ALLOC_BLOCKSIZE; \
68 	} while(0)
69 
70 #define ARRAYLIST_ADD(NEW_ITEM_P, ARRAY_LIST) do { \
71 		if ((ARRAY_LIST).len && !(ARRAY_LIST).allocated) { \
72 			NEW_ITEM_P = NULL; \
73 			break; \
74 		} \
75 		if ((ARRAY_LIST).head == NULL || (ARRAY_LIST).allocated < (ARRAY_LIST).len + 1) { \
76 			(ARRAY_LIST).allocated += (ARRAY_LIST).alloc_blocksize ? : 8; \
77 			(ARRAY_LIST).head = recallocarray((ARRAY_LIST).head, (ARRAY_LIST).len, \
78 							  (ARRAY_LIST).allocated, sizeof(*(ARRAY_LIST).head)); \
79 		}; \
80 		if (!(ARRAY_LIST).head || (ARRAY_LIST).allocated < (ARRAY_LIST).len + 1) { \
81 			NEW_ITEM_P = NULL; \
82 			break; \
83 		} \
84 		(NEW_ITEM_P) = &(ARRAY_LIST).head[(ARRAY_LIST).len]; \
85 		(ARRAY_LIST).len++; \
86 	} while (0)
87 
88 #define ARRAYLIST_CLEAR(ARRAY_LIST) \
89 	(ARRAY_LIST).len = 0
90 
91 #define ARRAYLIST_FREE(ARRAY_LIST) \
92 	do { \
93 		if ((ARRAY_LIST).head && (ARRAY_LIST).allocated) \
94 			free((ARRAY_LIST).head); \
95 		ARRAYLIST_INIT(ARRAY_LIST, (ARRAY_LIST).alloc_blocksize); \
96 	} while(0)