godot/core/os/pool_allocator.h
Rémi Verschelde d95794ec8a
One Copyright Update to rule them all
As many open source projects have started doing it, we're removing the
current year from the copyright notice, so that we don't need to bump
it every year.

It seems like only the first year of publication is technically
relevant for copyright notices, and even that seems to be something
that many companies stopped listing altogether (in a version controlled
codebase, the commits are a much better source of date of publication
than a hardcoded copyright statement).

We also now list Godot Engine contributors first as we're collectively
the current maintainers of the project, and we clarify that the
"exclusive" copyright of the co-founders covers the timespan before
opensourcing (their further contributions are included as part of Godot
Engine contributors).

Also fixed "cf." Frenchism - it's meant as "refer to / see".
2023-01-05 13:25:55 +01:00

149 lines
5.2 KiB
C++

/**************************************************************************/
/* pool_allocator.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* 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"
/**
* 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 allocation 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 = nullptr;
int *entry_indices = nullptr;
int entry_max = 0;
int entry_count = 0;
uint8_t *pool = nullptr;
void *mem_ptr = nullptr;
int pool_size = 0;
int free_mem = 0;
int free_mem_peak = 0;
unsigned int check_count = 0;
int align = 1;
bool needs_locking = false;
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, const 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