mirror of https://github.com/Relintai/sfw.git
111 lines
3.0 KiB
C++
111 lines
3.0 KiB
C++
#ifndef PAGED_ALLOCATOR_H
|
|
#define PAGED_ALLOCATOR_H
|
|
|
|
/*************************************************************************/
|
|
/* paged_allocator.h */
|
|
/* From https://github.com/Relintai/pandemonium_engine (MIT) */
|
|
/*************************************************************************/
|
|
|
|
//--STRIP
|
|
#include "core/memory.h"
|
|
#include "spin_lock.h"
|
|
#include "core/typedefs.h"
|
|
//--STRIP
|
|
|
|
template <class T, bool thread_safe = false>
|
|
class PagedAllocator {
|
|
T **page_pool = nullptr;
|
|
T ***available_pool = nullptr;
|
|
uint32_t pages_allocated = 0;
|
|
uint32_t allocs_available = 0;
|
|
|
|
uint32_t page_shift = 0;
|
|
uint32_t page_mask = 0;
|
|
uint32_t page_size = 0;
|
|
SpinLock spin_lock;
|
|
|
|
public:
|
|
T *alloc() {
|
|
if (thread_safe) {
|
|
spin_lock.lock();
|
|
}
|
|
if (unlikely(allocs_available == 0)) {
|
|
uint32_t pages_used = pages_allocated;
|
|
|
|
pages_allocated++;
|
|
page_pool = (T **)memrealloc(page_pool, sizeof(T *) * pages_allocated);
|
|
available_pool = (T ***)memrealloc(available_pool, sizeof(T **) * pages_allocated);
|
|
|
|
page_pool[pages_used] = (T *)memalloc(sizeof(T) * page_size);
|
|
available_pool[pages_used] = (T **)memalloc(sizeof(T *) * page_size);
|
|
|
|
for (uint32_t i = 0; i < page_size; i++) {
|
|
available_pool[0][i] = &page_pool[pages_used][i];
|
|
}
|
|
allocs_available += page_size;
|
|
}
|
|
|
|
allocs_available--;
|
|
T *alloc = available_pool[allocs_available >> page_shift][allocs_available & page_mask];
|
|
if (thread_safe) {
|
|
spin_lock.unlock();
|
|
}
|
|
memnew_placement(alloc, T);
|
|
return alloc;
|
|
}
|
|
|
|
void free(T *p_mem) {
|
|
if (thread_safe) {
|
|
spin_lock.lock();
|
|
}
|
|
p_mem->~T();
|
|
available_pool[allocs_available >> page_shift][allocs_available & page_mask] = p_mem;
|
|
if (thread_safe) {
|
|
spin_lock.unlock();
|
|
}
|
|
allocs_available++;
|
|
}
|
|
|
|
void reset(bool p_allow_unfreed = false) {
|
|
if (!p_allow_unfreed || !HAS_TRIVIAL_DESTRUCTOR(T)) {
|
|
ERR_FAIL_COND(allocs_available < pages_allocated * page_size);
|
|
}
|
|
if (pages_allocated) {
|
|
for (uint32_t i = 0; i < pages_allocated; i++) {
|
|
memfree(page_pool[i]);
|
|
memfree(available_pool[i]);
|
|
}
|
|
memfree(page_pool);
|
|
memfree(available_pool);
|
|
page_pool = nullptr;
|
|
available_pool = nullptr;
|
|
pages_allocated = 0;
|
|
allocs_available = 0;
|
|
}
|
|
}
|
|
bool is_configured() const {
|
|
return page_size > 0;
|
|
}
|
|
|
|
void configure(uint32_t p_page_size) {
|
|
ERR_FAIL_COND(page_pool != nullptr); //sanity check
|
|
ERR_FAIL_COND(p_page_size == 0);
|
|
page_size = nearest_power_of_2_templated(p_page_size);
|
|
page_mask = page_size - 1;
|
|
page_shift = get_shift_from_power_of_2(page_size);
|
|
}
|
|
|
|
// Power of 2 recommended because of alignment with OS page sizes.
|
|
// Even if element is bigger, its still a multiple and get rounded amount of pages
|
|
PagedAllocator(uint32_t p_page_size = 4096) {
|
|
configure(p_page_size);
|
|
}
|
|
|
|
~PagedAllocator() {
|
|
ERR_FAIL_COND_MSG(allocs_available < pages_allocated * page_size, "Pages in use exist at exit in PagedAllocator");
|
|
reset();
|
|
}
|
|
};
|
|
|
|
#endif // PAGED_ALLOCATOR_H
|