de6760166e93f142c33b0f431ed874f01f360d70
[babeltrace.git] / plugins / ctf / common / metadata / objstack.c
1 /*
2 * objstack.c
3 *
4 * Common Trace Format Object Stack.
5 *
6 * Copyright 2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
24 * SOFTWARE.
25 */
26
27 #include <stdlib.h>
28 #include <babeltrace/list-internal.h>
29 #include <babeltrace/babeltrace-internal.h>
30 #include <babeltrace/align-internal.h>
31
32 #define OBJSTACK_ALIGN 8 /* Object stack alignment */
33 #define OBJSTACK_INIT_LEN 128
34 #define OBJSTACK_POISON 0xcc
35
36 struct objstack {
37 struct bt_list_head head; /* list of struct objstack_node */
38 };
39
40 struct objstack_node {
41 struct bt_list_head node;
42 size_t len;
43 size_t used_len;
44 char __attribute__ ((aligned (OBJSTACK_ALIGN))) data[];
45 };
46
47 BT_HIDDEN
48 struct objstack *objstack_create(void)
49 {
50 struct objstack *objstack;
51 struct objstack_node *node;
52
53 objstack = calloc(1, sizeof(*objstack));
54 if (!objstack)
55 return NULL;
56 node = calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN,
57 sizeof(char));
58 if (!node) {
59 free(objstack);
60 return NULL;
61 }
62 BT_INIT_LIST_HEAD(&objstack->head);
63 bt_list_add_tail(&node->node, &objstack->head);
64 node->len = OBJSTACK_INIT_LEN;
65 return objstack;
66 }
67
68 static
69 void objstack_node_free(struct objstack_node *node)
70 {
71 size_t offset, len;
72 char *p;
73
74 if (!node)
75 return;
76 p = (char *) node;
77 len = sizeof(*node) + node->len;
78 for (offset = 0; offset < len; offset++)
79 p[offset] = OBJSTACK_POISON;
80 free(node);
81 }
82
83 BT_HIDDEN
84 void objstack_destroy(struct objstack *objstack)
85 {
86 struct objstack_node *node, *p;
87
88 if (!objstack)
89 return;
90 bt_list_for_each_entry_safe(node, p, &objstack->head, node) {
91 bt_list_del(&node->node);
92 objstack_node_free(node);
93 }
94 free(objstack);
95 }
96
97 static
98 struct objstack_node *objstack_append_node(struct objstack *objstack)
99 {
100 struct objstack_node *last_node, *new_node;
101
102 /* Get last node */
103 last_node = bt_list_entry(objstack->head.prev,
104 struct objstack_node, node);
105
106 /* Allocate new node with double of size of last node */
107 new_node = calloc(sizeof(struct objstack_node) + (last_node->len << 1),
108 sizeof(char));
109 if (!new_node) {
110 return NULL;
111 }
112 bt_list_add_tail(&new_node->node, &objstack->head);
113 new_node->len = last_node->len << 1;
114 return new_node;
115 }
116
117 BT_HIDDEN
118 void *objstack_alloc(struct objstack *objstack, size_t len)
119 {
120 struct objstack_node *last_node;
121 void *p;
122
123 len = ALIGN(len, OBJSTACK_ALIGN);
124
125 /* Get last node */
126 last_node = bt_list_entry(objstack->head.prev,
127 struct objstack_node, node);
128 while (last_node->len - last_node->used_len < len) {
129 last_node = objstack_append_node(objstack);
130 if (!last_node) {
131 return NULL;
132 }
133 }
134 p = &last_node->data[last_node->used_len];
135 last_node->used_len += len;
136 return p;
137 }
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