Merge branch 'tb/banned-vsprintf-namefix'
[git/git.git] / mem-pool.c
1 /*
2 * Memory Pool implementation logic.
3 */
4
5 #include "cache.h"
6 #include "mem-pool.h"
7
8 #define BLOCK_GROWTH_SIZE 1024*1024 - sizeof(struct mp_block);
9
10 /*
11 * Allocate a new mp_block and insert it after the block specified in
12 * `insert_after`. If `insert_after` is NULL, then insert block at the
13 * head of the linked list.
14 */
15 static struct mp_block *mem_pool_alloc_block(struct mem_pool *mem_pool, size_t block_alloc, struct mp_block *insert_after)
16 {
17 struct mp_block *p;
18
19 mem_pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
20 p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
21
22 p->next_free = (char *)p->space;
23 p->end = p->next_free + block_alloc;
24
25 if (insert_after) {
26 p->next_block = insert_after->next_block;
27 insert_after->next_block = p;
28 } else {
29 p->next_block = mem_pool->mp_block;
30 mem_pool->mp_block = p;
31 }
32
33 return p;
34 }
35
36 void mem_pool_init(struct mem_pool **mem_pool, size_t initial_size)
37 {
38 struct mem_pool *pool;
39
40 if (*mem_pool)
41 return;
42
43 pool = xcalloc(1, sizeof(*pool));
44
45 pool->block_alloc = BLOCK_GROWTH_SIZE;
46
47 if (initial_size > 0)
48 mem_pool_alloc_block(pool, initial_size, NULL);
49
50 *mem_pool = pool;
51 }
52
53 void mem_pool_discard(struct mem_pool *mem_pool, int invalidate_memory)
54 {
55 struct mp_block *block, *block_to_free;
56
57 block = mem_pool->mp_block;
58 while (block)
59 {
60 block_to_free = block;
61 block = block->next_block;
62
63 if (invalidate_memory)
64 memset(block_to_free->space, 0xDD, ((char *)block_to_free->end) - ((char *)block_to_free->space));
65
66 free(block_to_free);
67 }
68
69 free(mem_pool);
70 }
71
72 void *mem_pool_alloc(struct mem_pool *mem_pool, size_t len)
73 {
74 struct mp_block *p = NULL;
75 void *r;
76
77 /* round up to a 'uintmax_t' alignment */
78 if (len & (sizeof(uintmax_t) - 1))
79 len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
80
81 if (mem_pool->mp_block &&
82 mem_pool->mp_block->end - mem_pool->mp_block->next_free >= len)
83 p = mem_pool->mp_block;
84
85 if (!p) {
86 if (len >= (mem_pool->block_alloc / 2))
87 return mem_pool_alloc_block(mem_pool, len, mem_pool->mp_block);
88
89 p = mem_pool_alloc_block(mem_pool, mem_pool->block_alloc, NULL);
90 }
91
92 r = p->next_free;
93 p->next_free += len;
94 return r;
95 }
96
97 void *mem_pool_calloc(struct mem_pool *mem_pool, size_t count, size_t size)
98 {
99 size_t len = st_mult(count, size);
100 void *r = mem_pool_alloc(mem_pool, len);
101 memset(r, 0, len);
102 return r;
103 }
104
105 int mem_pool_contains(struct mem_pool *mem_pool, void *mem)
106 {
107 struct mp_block *p;
108
109 /* Check if memory is allocated in a block */
110 for (p = mem_pool->mp_block; p; p = p->next_block)
111 if ((mem >= ((void *)p->space)) &&
112 (mem < ((void *)p->end)))
113 return 1;
114
115 return 0;
116 }
117
118 void mem_pool_combine(struct mem_pool *dst, struct mem_pool *src)
119 {
120 struct mp_block *p;
121
122 /* Append the blocks from src to dst */
123 if (dst->mp_block && src->mp_block) {
124 /*
125 * src and dst have blocks, append
126 * blocks from src to dst.
127 */
128 p = dst->mp_block;
129 while (p->next_block)
130 p = p->next_block;
131
132 p->next_block = src->mp_block;
133 } else if (src->mp_block) {
134 /*
135 * src has blocks, dst is empty.
136 */
137 dst->mp_block = src->mp_block;
138 } else {
139 /* src is empty, nothing to do. */
140 }
141
142 dst->pool_alloc += src->pool_alloc;
143 src->pool_alloc = 0;
144 src->mp_block = NULL;
145 }