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/*************************************************************************/
/* pool_allocator.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#ifndef POOL_ALLOCATOR_H
#define POOL_ALLOCATOR_H
#include "core/typedefs.h"
/**
@author Juan Linietsky <reduzio@gmail.com>
* Generic Pool Allocator.
* This is a generic memory pool allocator, with locking, compacting and alignment. (@TODO alignment)
* It used as a standard way to manage alloction in a specific region of memory, such as texture memory,
* audio sample memory, or just any kind of memory overall.
* (@TODO) abstraction should be greater, because in many platforms, you need to manage a nonreachable memory.
*/
enum {
POOL_ALLOCATOR_INVALID_ID = -1 ///< default invalid value. use INVALID_ID( id ) to test
};
class PoolAllocator {
public:
typedef int ID;
private:
enum {
CHECK_BITS = 8,
CHECK_LEN = (1 << CHECK_BITS),
CHECK_MASK = CHECK_LEN - 1
};
struct Entry {
unsigned int pos = 0;
unsigned int len = 0;
unsigned int lock = 0;
unsigned int check = 0;
inline void clear() {
pos = 0;
len = 0;
lock = 0;
check = 0;
}
Entry() {}
};
typedef int EntryArrayPos;
typedef int EntryIndicesPos;
Entry *entry_array;
int *entry_indices;
int entry_max;
int entry_count;
uint8_t *pool;
void *mem_ptr;
int pool_size;
int free_mem;
int free_mem_peak;
unsigned int check_count;
int align;
bool needs_locking;
inline int entry_end(const Entry &p_entry) const {
return p_entry.pos + aligned(p_entry.len);
}
inline int aligned(int p_size) const {
int rem = p_size % align;
if (rem) {
p_size += align - rem;
}
return p_size;
}
void compact(int p_up_to = -1);
void compact_up(int p_from = 0);
bool get_free_entry(EntryArrayPos *p_pos);
bool find_hole(EntryArrayPos *p_pos, int p_for_size);
bool find_entry_index(EntryIndicesPos *p_map_pos, Entry *p_entry);
Entry *get_entry(ID p_mem);
const Entry *get_entry(ID p_mem) const;
void create_pool(void *p_mem, int p_size, int p_max_entries);
protected:
virtual void mt_lock() const; ///< Reimplement for custom mt locking
virtual void mt_unlock() const; ///< Reimplement for custom mt locking
public:
enum {
DEFAULT_MAX_ALLOCS = 4096,
};
ID alloc(int p_size); ///< Alloc memory, get an ID on success, POOL_ALOCATOR_INVALID_ID on failure
void free(ID p_mem); ///< Free allocated memory
Error resize(ID p_mem, int p_new_size); ///< resize a memory chunk
int get_size(ID p_mem) const;
int get_free_mem(); ///< get free memory
int get_used_mem() const;
int get_free_peak(); ///< get free memory
Error lock(ID p_mem); //@todo move this out
void *get(ID p_mem);
const void *get(ID p_mem) const;
void unlock(ID p_mem);
bool is_locked(ID p_mem) const;
PoolAllocator(int p_size, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS);
PoolAllocator(void *p_mem, int p_size, int p_align = 1, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS);
PoolAllocator(int p_align, int p_size, bool p_needs_locking = false, int p_max_entries = DEFAULT_MAX_ALLOCS);
virtual ~PoolAllocator();
};
#endif // POOL_ALLOCATOR_H
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