1/**************************************************************************/
2/* pool_allocator.h */
3/**************************************************************************/
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5/* GODOT ENGINE */
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9/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
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29/**************************************************************************/
30
31#ifndef POOL_ALLOCATOR_H
32#define POOL_ALLOCATOR_H
33
34#include "core/typedefs.h"
35
36/**
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 allocation 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
44enum {
45 POOL_ALLOCATOR_INVALID_ID = -1 ///< default invalid value. use INVALID_ID( id ) to test
46};
47
48class PoolAllocator {
49public:
50 typedef int ID;
51
52private:
53 enum {
54 CHECK_BITS = 8,
55 CHECK_LEN = (1 << CHECK_BITS),
56 CHECK_MASK = CHECK_LEN - 1
57
58 };
59
60 struct Entry {
61 unsigned int pos = 0;
62 unsigned int len = 0;
63 unsigned int lock = 0;
64 unsigned int check = 0;
65
66 inline void clear() {
67 pos = 0;
68 len = 0;
69 lock = 0;
70 check = 0;
71 }
72 Entry() {}
73 };
74
75 typedef int EntryArrayPos;
76 typedef int EntryIndicesPos;
77
78 Entry *entry_array = nullptr;
79 int *entry_indices = nullptr;
80 int entry_max = 0;
81 int entry_count = 0;
82
83 uint8_t *pool = nullptr;
84 void *mem_ptr = nullptr;
85 int pool_size = 0;
86
87 int free_mem = 0;
88 int free_mem_peak = 0;
89
90 unsigned int check_count = 0;
91 int align = 1;
92
93 bool needs_locking = false;
94
95 inline int entry_end(const Entry &p_entry) const {
96 return p_entry.pos + aligned(p_entry.len);
97 }
98 inline int aligned(int p_size) const {
99 int rem = p_size % align;
100 if (rem) {
101 p_size += align - rem;
102 }
103
104 return p_size;
105 }
106
107 void compact(int p_up_to = -1);
108 void compact_up(int p_from = 0);
109 bool get_free_entry(EntryArrayPos *p_pos);
110 bool find_hole(EntryArrayPos *p_pos, int p_for_size);
111 bool find_entry_index(EntryIndicesPos *p_map_pos, const Entry *p_entry);
112 Entry *get_entry(ID p_mem);
113 const Entry *get_entry(ID p_mem) const;
114
115 void create_pool(void *p_mem, int p_size, int p_max_entries);
116
117protected:
118 virtual void mt_lock() const; ///< Reimplement for custom mt locking
119 virtual void mt_unlock() const; ///< Reimplement for custom mt locking
120
121public:
122 enum {
123 DEFAULT_MAX_ALLOCS = 4096,
124 };
125
126 ID alloc(int p_size); ///< Alloc memory, get an ID on success, POOL_ALOCATOR_INVALID_ID on failure
127 void free(ID p_mem); ///< Free allocated memory
128 Error resize(ID p_mem, int p_new_size); ///< resize a memory chunk
129 int get_size(ID p_mem) const;
130
131 int get_free_mem(); ///< get free memory
132 int get_used_mem() const;
133 int get_free_peak(); ///< get free memory
134
135 Error lock(ID p_mem); //@todo move this out
136 void *get(ID p_mem);
137 const void *get(ID p_mem) const;
138 void unlock(ID p_mem);
139 bool is_locked(ID p_mem) const;
140
141 PoolAllocator(int p_size, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS);
142 PoolAllocator(void *p_mem, int p_size, int p_align = 1, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS);
143 PoolAllocator(int p_align, int p_size, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS);
144
145 virtual ~PoolAllocator();
146};
147
148#endif // POOL_ALLOCATOR_H
149