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// ------------------------------------------------------------------------
// object_queue.cpp: Thread-safe way to transmit generic objects (FIFO).
// Copyright (C) 1999-2000 Kai Vehmanen
//
// 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
// ------------------------------------------------------------------------
#ifndef INCLUDED_OBJECT_QUEUE_H
#define INCLUDED_OBJECT_QUEUE_H
#include <pthread.h>
#include <deque>
/**
* Thread-safe way to transmit generic objects (FIFO-queue).
*/
template<class T>
class OBJECT_QUEUE {
private:
deque<T> cmds_rep;
mutable pthread_mutex_t lock_rep;
public:
/**
* Inserts 'obj' into the queue. If some other process is
* accessing the queue, this call will block.
*/
void push_back(const T& obj) {
pthread_mutex_lock(&lock_rep);
cmds_rep.push_back(obj);
pthread_mutex_unlock(&lock_rep);
}
/**
* Pops the first item. If some other process is
* accessing the queue, this call will block.
*/
void pop_front(void) {
pthread_mutex_lock(&lock_rep);
cmds_rep.pop_front();
pthread_mutex_unlock(&lock_rep);
}
/**
* Returns the first item. If some other process is
* accessing the queue, this call will block.
*/
T front(void) const {
T temporary;
pthread_mutex_lock(&lock_rep);
if (cmds_rep.size() > 0) {
temporary = cmds_rep.front();
}
pthread_mutex_unlock(&lock_rep);
return(temporary);
}
/**
* Returns true if the queue is empty. Unlike other calls,
* this call will not block if some other process is
* accessing the queue. In this case, the returned result
* will be 'true' even if the queue wasn't empty.
*/
bool is_empty(void) const {
if (pthread_mutex_trylock(&lock_rep) != 0)
return(true);
bool temp = true;
if (cmds_rep.size() > 0) temp = false;
pthread_mutex_unlock(&lock_rep);
return(temp);
}
/**
* Clears the queue. If some other process is
* accessing the queue, this call will block.
*/
void clear(void) {
pthread_mutex_lock(&lock_rep);
while (cmds_repsize() > 0) cmds_rep.pop_front();
pthread_mutex_unlock(&lock_rep);
}
OBJECT_QUEUE(void) {
pthread_mutex_init(&lock_rep, NULL);
}
~OBJECT_QUEUE(void) {
pthread_mutex_destroy(&lock_rep);
}
};
#endif
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