168 lines
3.9 KiB
C++
168 lines
3.9 KiB
C++
/**
|
|
*
|
|
* ***** BEGIN GPL LICENSE BLOCK *****
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version 2
|
|
* of the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software Foundation,
|
|
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*
|
|
* Contributor(s): Peter Schlaile <peter@schlaile.de> 2005
|
|
*
|
|
* ***** END GPL LICENSE BLOCK *****
|
|
*/
|
|
|
|
#ifndef __MEM_cache_limiter_h_included__
|
|
#define __MEM_cache_limiter_h_included__ 1
|
|
|
|
/**
|
|
* @section MEM_CacheLimiter
|
|
* This class defines a generic memory cache management system
|
|
* to limit memory usage to a fixed global maximum.
|
|
*
|
|
* Please use the C-API in MEM_CacheLimiterC-Api.h for code written in C.
|
|
*
|
|
* Usage example:
|
|
*
|
|
* class BigFatImage {
|
|
* public:
|
|
* ~BigFatImage() { tell_everyone_we_are_gone(this); }
|
|
* };
|
|
*
|
|
* void doit() {
|
|
* MEM_Cache<BigFatImage> BigFatImages;
|
|
*
|
|
* MEM_Cache_Handle<BigFatImage>* h = BigFatImages.insert(new BigFatImage);
|
|
*
|
|
* BigFatImages.enforce_limits();
|
|
* h->ref();
|
|
*
|
|
* work with image...
|
|
*
|
|
* h->unref();
|
|
*
|
|
* leave image in cache.
|
|
*/
|
|
|
|
#include <list>
|
|
#include "MEM_Allocator.h"
|
|
|
|
template<class T>
|
|
class MEM_CacheLimiter;
|
|
|
|
#ifndef __MEM_cache_limiter_c_api_h_included__
|
|
extern "C" {
|
|
extern void MEM_CacheLimiter_set_maximum(int m);
|
|
extern int MEM_CacheLimiter_get_maximum();
|
|
// this is rather _ugly_!
|
|
extern int mem_in_use;
|
|
extern int mmap_in_use;
|
|
};
|
|
#endif
|
|
|
|
template<class T>
|
|
class MEM_CacheLimiterHandle {
|
|
public:
|
|
explicit MEM_CacheLimiterHandle(T * data_,
|
|
MEM_CacheLimiter<T> * parent_)
|
|
: data(data_), refcount(0), parent(parent_) { }
|
|
|
|
void ref() {
|
|
refcount++;
|
|
}
|
|
void unref() {
|
|
refcount--;
|
|
}
|
|
T * get() {
|
|
return data;
|
|
}
|
|
const T * get() const {
|
|
return data;
|
|
}
|
|
int get_refcount() const {
|
|
return refcount;
|
|
}
|
|
bool can_destroy() const {
|
|
return !data || !refcount;
|
|
}
|
|
bool destroy_if_possible() {
|
|
if (can_destroy()) {
|
|
delete data;
|
|
data = 0;
|
|
unmanage();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
void unmanage() {
|
|
parent->unmanage(this);
|
|
}
|
|
void touch() {
|
|
parent->touch(this);
|
|
}
|
|
private:
|
|
friend class MEM_CacheLimiter<T>;
|
|
|
|
T * data;
|
|
int refcount;
|
|
typename std::list<MEM_CacheLimiterHandle<T> *,
|
|
MEM_Allocator<MEM_CacheLimiterHandle<T> *> >::iterator me;
|
|
MEM_CacheLimiter<T> * parent;
|
|
};
|
|
|
|
template<class T>
|
|
class MEM_CacheLimiter {
|
|
public:
|
|
typedef typename std::list<MEM_CacheLimiterHandle<T> *,
|
|
MEM_Allocator<MEM_CacheLimiterHandle<T> *> >::iterator iterator;
|
|
~MEM_CacheLimiter() {
|
|
for (iterator it = queue.begin(); it != queue.end(); it++) {
|
|
delete *it;
|
|
}
|
|
}
|
|
MEM_CacheLimiterHandle<T> * insert(T * elem) {
|
|
queue.push_back(new MEM_CacheLimiterHandle<T>(elem, this));
|
|
iterator it = queue.end();
|
|
--it;
|
|
queue.back()->me = it;
|
|
return queue.back();
|
|
}
|
|
void unmanage(MEM_CacheLimiterHandle<T> * handle) {
|
|
queue.erase(handle->me);
|
|
delete handle;
|
|
}
|
|
void enforce_limits() {
|
|
int max = MEM_CacheLimiter_get_maximum();
|
|
if (max == 0) {
|
|
return;
|
|
}
|
|
for (iterator it = queue.begin();
|
|
it != queue.end() && mem_in_use + mmap_in_use > max;) {
|
|
iterator jt = it;
|
|
++it;
|
|
(*jt)->destroy_if_possible();
|
|
}
|
|
}
|
|
void touch(MEM_CacheLimiterHandle<T> * handle) {
|
|
queue.push_back(handle);
|
|
queue.erase(handle->me);
|
|
iterator it = queue.end();
|
|
--it;
|
|
handle->me = it;
|
|
}
|
|
private:
|
|
std::list<MEM_CacheLimiterHandle<T>*,
|
|
MEM_Allocator<MEM_CacheLimiterHandle<T> *> > queue;
|
|
};
|
|
|
|
#endif
|