87 lines
1.8 KiB
C++
87 lines
1.8 KiB
C++
/*
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Copyright (C) 2000 Paul Barton-Davis
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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$Id$
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*/
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#ifndef __pbd_lockfree_fifo_h__
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#define __pbd_lockfree_fifo_h__
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#include <sys/types.h>
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#include <cstdlib>
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template<class T>
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class LockFreeFIFO
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{
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public:
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LockFreeFIFO (int sz) {
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size = sz;
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push_ptr = 0;
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pop_ptr = 0;
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buf = new T[size];
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};
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virtual ~LockFreeFIFO() {
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delete [] buf;
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}
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int pop (T& r) {
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if (pop_ptr == push_ptr) {
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return -1;
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} else {
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r = buf[pop_ptr];
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pop_ptr++;
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if (pop_ptr >= size) {
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pop_ptr = 0;
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}
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return 0;
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}
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}
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int top (T& r) {
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if (pop_ptr == push_ptr) {
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return -1;
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} else {
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r = buf[pop_ptr];
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return 0;
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}
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}
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int push (T& t) {
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if ((size_t) abs (static_cast<int>(push_ptr - pop_ptr)) < size) {
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buf[push_ptr] = t;
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push_ptr++;
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if (push_ptr >= size) {
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push_ptr = 0;
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}
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return 0;
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} else {
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return -1;
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}
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}
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protected:
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T *buf;
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volatile size_t push_ptr;
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volatile size_t pop_ptr;
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size_t size;
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};
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#endif /* __pbd_lockfree_fifo_h__ */
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