1 /*
2 * Copyright 2009 Nicolai Hähnle <nhaehnle@gmail.com>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * on the rights to use, copy, modify, merge, publish, distribute, sub
8 * license, and/or sell copies of the Software, and to permit persons to whom
9 * the Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
21 * USE OR OTHER DEALINGS IN THE SOFTWARE. */
22
23 #include "memory_pool.h"
24
25 #include <assert.h>
26 #include <stdlib.h>
27 #include <string.h>
28
29
30 #define POOL_LARGE_ALLOC 4096
31 #define POOL_ALIGN 8
32
33
34 struct memory_block {
35 struct memory_block * next;
36 };
37
memory_pool_init(struct memory_pool * pool)38 void memory_pool_init(struct memory_pool * pool)
39 {
40 memset(pool, 0, sizeof(struct memory_pool));
41 }
42
43
memory_pool_destroy(struct memory_pool * pool)44 void memory_pool_destroy(struct memory_pool * pool)
45 {
46 while(pool->blocks) {
47 struct memory_block * block = pool->blocks;
48 pool->blocks = block->next;
49 free(block);
50 }
51 }
52
refill_pool(struct memory_pool * pool)53 static void refill_pool(struct memory_pool * pool)
54 {
55 unsigned int blocksize = pool->total_allocated;
56 struct memory_block * newblock;
57
58 if (!blocksize)
59 blocksize = 2*POOL_LARGE_ALLOC;
60
61 newblock = (struct memory_block*)malloc(blocksize);
62 newblock->next = pool->blocks;
63 pool->blocks = newblock;
64
65 pool->head = (unsigned char*)(newblock + 1);
66 pool->end = ((unsigned char*)newblock) + blocksize;
67 pool->total_allocated += blocksize;
68 }
69
70
memory_pool_malloc(struct memory_pool * pool,unsigned int bytes)71 void * memory_pool_malloc(struct memory_pool * pool, unsigned int bytes)
72 {
73 if (bytes < POOL_LARGE_ALLOC) {
74 void * ptr;
75
76 if (pool->head + bytes > pool->end)
77 refill_pool(pool);
78
79 assert(pool->head + bytes <= pool->end);
80
81 ptr = pool->head;
82
83 pool->head += bytes;
84 pool->head = (unsigned char*)(((unsigned long)pool->head + POOL_ALIGN - 1) & ~(POOL_ALIGN - 1));
85
86 return ptr;
87 } else {
88 struct memory_block * block = (struct memory_block*)malloc(bytes + sizeof(struct memory_block));
89
90 block->next = pool->blocks;
91 pool->blocks = block;
92
93 return (block + 1);
94 }
95 }
96
97
98