sfw/sfwl/core/pool_allocator.h

132 lines
3.3 KiB
C++

//--STRIP
#ifndef POOL_ALLOCATOR_H
#define POOL_ALLOCATOR_H
//--STRIP
/*************************************************************************/
/* pool_allocator.h */
/* From https://github.com/Relintai/pandemonium_engine (MIT) */
/*************************************************************************/
//--STRIP
#include "core/typedefs.h"
//--STRIP
/**
@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 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;
unsigned int len;
unsigned int lock;
unsigned int check;
inline void clear() {
pos = 0;
len = 0;
lock = 0;
check = 0;
}
Entry() { clear(); }
};
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();
};
//--STRIP
#endif
//--STRIP