1 /*************************************************************************/ 2 /* pool_allocator.h */ 3 /*************************************************************************/ 4 /* This file is part of: */ 5 /* GODOT ENGINE */ 6 /* https://godotengine.org */ 7 /*************************************************************************/ 8 /* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */ 9 /* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */ 10 /* */ 11 /* Permission is hereby granted, free of charge, to any person obtaining */ 12 /* a copy of this software and associated documentation files (the */ 13 /* "Software"), to deal in the Software without restriction, including */ 14 /* without limitation the rights to use, copy, modify, merge, publish, */ 15 /* distribute, sublicense, and/or sell copies of the Software, and to */ 16 /* permit persons to whom the Software is furnished to do so, subject to */ 17 /* the following conditions: */ 18 /* */ 19 /* The above copyright notice and this permission notice shall be */ 20 /* included in all copies or substantial portions of the Software. */ 21 /* */ 22 /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ 23 /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ 24 /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/ 25 /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ 26 /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ 27 /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ 28 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ 29 /*************************************************************************/ 30 #ifndef POOL_ALLOCATOR_H 31 #define POOL_ALLOCATOR_H 32 33 #include "typedefs.h" 34 35 /** 36 @author Juan Linietsky <reduzio@gmail.com> 37 * Generic Pool Allocator. 38 * This is a generic memory pool allocator, with locking, compacting and alignment. (@TODO alignment) 39 * It used as a standard way to manage alloction in a specific region of memory, such as texture memory, 40 * audio sample memory, or just any kind of memory overall. 41 * (@TODO) abstraction should be greater, because in many platforms, you need to manage a nonreachable memory. 42 */ 43 44 enum { 45 46 POOL_ALLOCATOR_INVALID_ID = -1 ///< default invalid value. use INVALID_ID( id ) to test 47 }; 48 49 class PoolAllocator { 50 public: 51 typedef int ID; 52 53 private: 54 enum { 55 CHECK_BITS = 8, 56 CHECK_LEN = (1 << CHECK_BITS), 57 CHECK_MASK = CHECK_LEN - 1 58 59 }; 60 61 struct Entry { 62 63 unsigned int pos; 64 unsigned int len; 65 unsigned int lock; 66 unsigned int check; 67 clearEntry68 inline void clear() { 69 pos = 0; 70 len = 0; 71 lock = 0; 72 check = 0; 73 } EntryEntry74 Entry() { clear(); } 75 }; 76 77 typedef int EntryArrayPos; 78 typedef int EntryIndicesPos; 79 80 Entry *entry_array; 81 int *entry_indices; 82 int entry_max; 83 int entry_count; 84 85 uint8_t *pool; 86 void *mem_ptr; 87 int pool_size; 88 89 int free_mem; 90 int free_mem_peak; 91 92 unsigned int check_count; 93 int align; 94 95 bool needs_locking; 96 entry_end(const Entry & p_entry)97 inline int entry_end(const Entry &p_entry) const { 98 return p_entry.pos + aligned(p_entry.len); 99 } aligned(int p_size)100 inline int aligned(int p_size) const { 101 102 int rem = p_size % align; 103 if (rem) 104 p_size += align - rem; 105 106 return p_size; 107 } 108 109 void compact(int p_up_to = -1); 110 void compact_up(int p_from = 0); 111 bool get_free_entry(EntryArrayPos *p_pos); 112 bool find_hole(EntryArrayPos *p_pos, int p_for_size); 113 bool find_entry_index(EntryIndicesPos *p_map_pos, Entry *p_entry); 114 Entry *get_entry(ID p_mem); 115 const Entry *get_entry(ID p_mem) const; 116 117 void create_pool(void *p_mem, int p_size, int p_max_entries); 118 119 protected: 120 virtual void mt_lock() const; ///< Reimplement for custom mt locking 121 virtual void mt_unlock() const; ///< Reimplement for custom mt locking 122 123 public: 124 enum { 125 DEFAULT_MAX_ALLOCS = 4096, 126 }; 127 128 ID alloc(int p_size); ///< Alloc memory, get an ID on success, POOL_ALOCATOR_INVALID_ID on failure 129 void free(ID p_mem); ///< Free allocated memory 130 Error resize(ID p_mem, int p_new_size); ///< resize a memory chunk 131 int get_size(ID p_mem) const; 132 133 int get_free_mem(); ///< get free memory 134 int get_used_mem() const; 135 int get_free_peak(); ///< get free memory 136 137 Error lock(ID p_mem); //@todo move this out 138 void *get(ID p_mem); 139 const void *get(ID p_mem) const; 140 void unlock(ID p_mem); 141 bool is_locked(ID p_mem) const; 142 143 PoolAllocator(int p_size, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS); 144 PoolAllocator(void *p_mem, int p_size, int p_align = 1, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS); 145 PoolAllocator(int p_align, int p_size, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS); 146 147 virtual ~PoolAllocator(); 148 }; 149 150 #endif 151