1 /*
2 +----------------------------------------------------------------------+
3 | Zend Engine |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 1998-2018 Zend Technologies Ltd. (http://www.zend.com) |
6 +----------------------------------------------------------------------+
7 | This source file is subject to version 2.00 of the Zend license, |
8 | that is bundled with this package in the file LICENSE, and is |
9 | available through the world-wide-web at the following url: |
10 | http://www.zend.com/license/2_00.txt. |
11 | If you did not receive a copy of the Zend license and are unable to |
12 | obtain it through the world-wide-web, please send a note to |
13 | license@zend.com so we can mail you a copy immediately. |
14 +----------------------------------------------------------------------+
15 | Authors: Dmitry Stogov <dmitry@php.net> |
16 +----------------------------------------------------------------------+
17 */
18
19 #ifndef _ZEND_ARENA_H_
20 #define _ZEND_ARENA_H_
21
22 #include "zend.h"
23
24 typedef struct _zend_arena zend_arena;
25
26 struct _zend_arena {
27 char *ptr;
28 char *end;
29 zend_arena *prev;
30 };
31
zend_arena_create(size_t size)32 static zend_always_inline zend_arena* zend_arena_create(size_t size)
33 {
34 zend_arena *arena = (zend_arena*)emalloc(size);
35
36 arena->ptr = (char*) arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena));
37 arena->end = (char*) arena + size;
38 arena->prev = NULL;
39 return arena;
40 }
41
zend_arena_destroy(zend_arena * arena)42 static zend_always_inline void zend_arena_destroy(zend_arena *arena)
43 {
44 do {
45 zend_arena *prev = arena->prev;
46 efree(arena);
47 arena = prev;
48 } while (arena);
49 }
50
51 #define ZEND_ARENA_ALIGNMENT 8U
52
zend_arena_alloc(zend_arena ** arena_ptr,size_t size)53 static zend_always_inline void* zend_arena_alloc(zend_arena **arena_ptr, size_t size)
54 {
55 zend_arena *arena = *arena_ptr;
56 char *ptr = arena->ptr;
57
58 size = ZEND_MM_ALIGNED_SIZE(size);
59
60 if (EXPECTED(size <= (size_t)(arena->end - ptr))) {
61 arena->ptr = ptr + size;
62 } else {
63 size_t arena_size =
64 UNEXPECTED((size + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena))) > (size_t)(arena->end - (char*) arena)) ?
65 (size + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena))) :
66 (size_t)(arena->end - (char*) arena);
67 zend_arena *new_arena = (zend_arena*)emalloc(arena_size);
68
69 ptr = (char*) new_arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena));
70 new_arena->ptr = (char*) new_arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena)) + size;
71 new_arena->end = (char*) new_arena + arena_size;
72 new_arena->prev = arena;
73 *arena_ptr = new_arena;
74 }
75
76 return (void*) ptr;
77 }
78
zend_arena_calloc(zend_arena ** arena_ptr,size_t count,size_t unit_size)79 static zend_always_inline void* zend_arena_calloc(zend_arena **arena_ptr, size_t count, size_t unit_size)
80 {
81 int overflow;
82 size_t size;
83 void *ret;
84
85 size = zend_safe_address(unit_size, count, 0, &overflow);
86 if (UNEXPECTED(overflow)) {
87 zend_error(E_ERROR, "Possible integer overflow in zend_arena_calloc() (%zu * %zu)", unit_size, count);
88 }
89 ret = zend_arena_alloc(arena_ptr, size);
90 memset(ret, 0, size);
91 return ret;
92 }
93
zend_arena_checkpoint(zend_arena * arena)94 static zend_always_inline void* zend_arena_checkpoint(zend_arena *arena)
95 {
96 return arena->ptr;
97 }
98
zend_arena_release(zend_arena ** arena_ptr,void * checkpoint)99 static zend_always_inline void zend_arena_release(zend_arena **arena_ptr, void *checkpoint)
100 {
101 zend_arena *arena = *arena_ptr;
102
103 while (UNEXPECTED((char*)checkpoint > arena->end) ||
104 UNEXPECTED((char*)checkpoint <= (char*)arena)) {
105 zend_arena *prev = arena->prev;
106 efree(arena);
107 *arena_ptr = arena = prev;
108 }
109 ZEND_ASSERT((char*)checkpoint > (char*)arena && (char*)checkpoint <= arena->end);
110 arena->ptr = (char*)checkpoint;
111 }
112
zend_arena_contains(zend_arena * arena,void * ptr)113 static zend_always_inline zend_bool zend_arena_contains(zend_arena *arena, void *ptr)
114 {
115 while (arena) {
116 if ((char*)ptr > (char*)arena && (char*)ptr <= arena->ptr) {
117 return 1;
118 }
119 arena = arena->prev;
120 }
121 return 0;
122 }
123
124 #endif /* _ZEND_ARENA_H_ */
125
126 /*
127 * Local variables:
128 * tab-width: 4
129 * c-basic-offset: 4
130 * indent-tabs-mode: t
131 * End:
132 * vim600: sw=4 ts=4 fdm=marker
133 * vim<600: sw=4 ts=4
134 */
135
