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/*
Copyright (C) 2000 Paul Barton-Davis
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., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id$
*/
#ifndef __pbd_lockfree_fifo_h__
#define __pbd_lockfree_fifo_h__
#include <sys/types.h>
#include <cstdlib>
template<class T>
class LockFreeFIFO
{
public:
LockFreeFIFO (int sz) {
size = sz;
push_ptr = 0;
pop_ptr = 0;
buf = new T[size];
};
virtual ~LockFreeFIFO() {
delete [] buf;
}
int pop (T& r) {
if (pop_ptr == push_ptr) {
return -1;
} else {
r = buf[pop_ptr];
pop_ptr++;
if (pop_ptr >= size) {
pop_ptr = 0;
}
return 0;
}
}
int top (T& r) {
if (pop_ptr == push_ptr) {
return -1;
} else {
r = buf[pop_ptr];
return 0;
}
}
int push (T& t) {
if ((size_t) abs (static_cast<int>(push_ptr - pop_ptr)) < size) {
buf[push_ptr] = t;
push_ptr++;
if (push_ptr >= size) {
push_ptr = 0;
}
return 0;
} else {
return -1;
}
}
protected:
T *buf;
volatile size_t push_ptr;
volatile size_t pop_ptr;
size_t size;
};
#endif /* __pbd_lockfree_fifo_h__ */
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