godot/core/allocators.h
Rémi Verschelde f8db8a3faa Bring that Whole New World to the Old Continent too
Applies the clang-format style to the 2.1 branch as done for master in
5dbf1809c6.
2017-03-19 00:36:26 +01:00

193 lines
4.7 KiB
C++

/*************************************************************************/
/* allocators.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* http://www.godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2017 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 ALLOCATORS_H
#define ALLOCATORS_H
#include "os/memory.h"
template <int PREALLOC_COUNT = 64, int MAX_HANDS = 8>
class BalloonAllocator {
enum {
USED_FLAG = (1 << 30),
USED_MASK = USED_FLAG - 1
};
struct Balloon {
Balloon *next;
Balloon *prev;
uint32_t hand;
};
struct Hand {
int used;
int allocated;
Balloon *first;
Balloon *last;
};
Hand hands[MAX_HANDS];
public:
void *alloc(size_t p_size) {
size_t max = (1 << MAX_HANDS);
ERR_FAIL_COND_V(p_size > max, NULL);
unsigned int hand = 0;
while (p_size > (size_t)(1 << hand))
++hand;
Hand &h = hands[hand];
if (h.used == h.allocated) {
for (int i = 0; i < PREALLOC_COUNT; i++) {
Balloon *b = (Balloon *)memalloc(sizeof(Balloon) + (1 << hand));
b->hand = hand;
if (h.last) {
b->prev = h.last;
h.last->next = b;
h.last = b;
} else {
b->prev = NULL;
h.last = b;
h.first = b;
}
}
h.last->next = NULL;
h.allocated += PREALLOC_COUNT;
}
Balloon *pick = h.last;
ERR_FAIL_COND_V((pick->hand & USED_FLAG), NULL);
// remove last
h.last = h.last->prev;
h.last->next = NULL;
pick->next = h.first;
h.first->prev = pick;
pick->prev = NULL;
h.first = pick;
h.used++;
pick->hand |= USED_FLAG;
return (void *)(pick + 1);
}
void free(void *p_ptr) {
Balloon *b = (Balloon *)p_ptr;
b -= 1;
ERR_FAIL_COND(!(b->hand & USED_FLAG));
b->hand = b->hand & USED_MASK; // not used
int hand = b->hand;
Hand &h = hands[hand];
if (b == h.first)
h.first = b->next;
if (b->prev)
b->prev->next = b->next;
if (b->next)
b->next->prev = b->prev;
if (h.last != b) {
h.last->next = b;
b->prev = h.last;
b->next = NULL;
h.last = b;
}
h.used--;
if (h.used <= (h.allocated - (PREALLOC_COUNT * 2))) { // this is done to ensure no alloc/free is done constantly
for (int i = 0; i < PREALLOC_COUNT; i++) {
ERR_CONTINUE(h.last->hand & USED_FLAG);
Balloon *new_last = h.last->prev;
if (new_last)
new_last->next = NULL;
memfree(h.last);
h.last = new_last;
}
h.allocated -= PREALLOC_COUNT;
}
}
BalloonAllocator() {
for (int i = 0; i < MAX_HANDS; i++) {
hands[i].allocated = 0;
hands[i].used = 0;
hands[i].first = NULL;
hands[i].last = NULL;
}
}
void clear() {
for (int i = 0; i < MAX_HANDS; i++) {
while (hands[i].first) {
Balloon *b = hands[i].first;
hands[i].first = b->next;
memfree(b);
}
hands[i].allocated = 0;
hands[i].used = 0;
hands[i].first = NULL;
hands[i].last = NULL;
}
}
~BalloonAllocator() {
clear();
}
};
#endif // ALLOCATORS_H