zend_arena.h 3.9 KB

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  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. #ifndef _ZEND_ARENA_H_
  19. #define _ZEND_ARENA_H_
  20. #include "zend.h"
  21. typedef struct _zend_arena zend_arena;
  22. struct _zend_arena {
  23. char *ptr;
  24. char *end;
  25. zend_arena *prev;
  26. };
  27. static zend_always_inline zend_arena* zend_arena_create(size_t size)
  28. {
  29. zend_arena *arena = (zend_arena*)emalloc(size);
  30. arena->ptr = (char*) arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena));
  31. arena->end = (char*) arena + size;
  32. arena->prev = NULL;
  33. return arena;
  34. }
  35. static zend_always_inline void zend_arena_destroy(zend_arena *arena)
  36. {
  37. do {
  38. zend_arena *prev = arena->prev;
  39. efree(arena);
  40. arena = prev;
  41. } while (arena);
  42. }
  43. #define ZEND_ARENA_ALIGNMENT 8U
  44. static zend_always_inline void* zend_arena_alloc(zend_arena **arena_ptr, size_t size)
  45. {
  46. zend_arena *arena = *arena_ptr;
  47. char *ptr = arena->ptr;
  48. size = ZEND_MM_ALIGNED_SIZE(size);
  49. if (EXPECTED(size <= (size_t)(arena->end - ptr))) {
  50. arena->ptr = ptr + size;
  51. } else {
  52. size_t arena_size =
  53. UNEXPECTED((size + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena))) > (size_t)(arena->end - (char*) arena)) ?
  54. (size + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena))) :
  55. (size_t)(arena->end - (char*) arena);
  56. zend_arena *new_arena = (zend_arena*)emalloc(arena_size);
  57. ptr = (char*) new_arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena));
  58. new_arena->ptr = (char*) new_arena + ZEND_MM_ALIGNED_SIZE(sizeof(zend_arena)) + size;
  59. new_arena->end = (char*) new_arena + arena_size;
  60. new_arena->prev = arena;
  61. *arena_ptr = new_arena;
  62. }
  63. return (void*) ptr;
  64. }
  65. static zend_always_inline void* zend_arena_calloc(zend_arena **arena_ptr, size_t count, size_t unit_size)
  66. {
  67. int overflow;
  68. size_t size;
  69. void *ret;
  70. size = zend_safe_address(unit_size, count, 0, &overflow);
  71. if (UNEXPECTED(overflow)) {
  72. zend_error(E_ERROR, "Possible integer overflow in zend_arena_calloc() (%zu * %zu)", unit_size, count);
  73. }
  74. ret = zend_arena_alloc(arena_ptr, size);
  75. memset(ret, 0, size);
  76. return ret;
  77. }
  78. static zend_always_inline void* zend_arena_checkpoint(zend_arena *arena)
  79. {
  80. return arena->ptr;
  81. }
  82. static zend_always_inline void zend_arena_release(zend_arena **arena_ptr, void *checkpoint)
  83. {
  84. zend_arena *arena = *arena_ptr;
  85. while (UNEXPECTED((char*)checkpoint > arena->end) ||
  86. UNEXPECTED((char*)checkpoint <= (char*)arena)) {
  87. zend_arena *prev = arena->prev;
  88. efree(arena);
  89. *arena_ptr = arena = prev;
  90. }
  91. ZEND_ASSERT((char*)checkpoint > (char*)arena && (char*)checkpoint <= arena->end);
  92. arena->ptr = (char*)checkpoint;
  93. }
  94. static zend_always_inline zend_bool zend_arena_contains(zend_arena *arena, void *ptr)
  95. {
  96. while (arena) {
  97. if ((char*)ptr > (char*)arena && (char*)ptr <= arena->ptr) {
  98. return 1;
  99. }
  100. arena = arena->prev;
  101. }
  102. return 0;
  103. }
  104. #endif /* _ZEND_ARENA_H_ */
  105. /*
  106. * Local variables:
  107. * tab-width: 4
  108. * c-basic-offset: 4
  109. * indent-tabs-mode: t
  110. * End:
  111. * vim600: sw=4 ts=4 fdm=marker
  112. * vim<600: sw=4 ts=4
  113. */