1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
/*
Copyright (C) 2007, 2008, 2009, 2010, 2011 Her Majesty the Queen in
Right of Canada (Communications Research Center Canada)
Copyright (C) 2013, 2014
Matthias P. Braendli, matthias.braendli@mpb.li
An implementation for a threadsafe queue using boost thread library
When creating a ThreadsafeQueue, one can specify the minimal number
of elements it must contain before it is possible to take one
element out.
*/
/*
This file is part of ODR-DabMux.
ODR-DabMux 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 3 of the
License, or (at your option) any later version.
ODR-DabMux 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 ODR-DabMux. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef THREADSAFE_QUEUE_H
#define THREADSAFE_QUEUE_H
#include <boost/thread.hpp>
#include <queue>
/* This queue is meant to be used by two threads. One producer
* that pushes elements into the queue, and one consumer that
* retrieves the elements.
*
* The queue can make the consumer block until an element
* is available.
*/
template<typename T>
class ThreadsafeQueue
{
public:
/* Push one element into the queue, and notify another thread that
* might be waiting.
*
* returns the new queue size.
*/
size_t push(T const& val)
{
boost::mutex::scoped_lock lock(the_mutex);
the_queue.push(val);
size_t queue_size = the_queue.size();
lock.unlock();
the_rx_notification.notify_one();
return queue_size;
}
/* Push one element into the queue, but wait until the
* queue size goes below the threshold.
*
* Notify waiting thread.
*
* returns the new queue size.
*/
size_t push_wait_if_full(T const& val, size_t threshold)
{
boost::mutex::scoped_lock lock(the_mutex);
while (the_queue.size() >= threshold) {
the_tx_notification.wait(lock);
}
the_queue.push(val);
size_t queue_size = the_queue.size();
lock.unlock();
the_rx_notification.notify_one();
return queue_size;
}
/* Send a notification for the receiver thread */
void notify(void)
{
the_rx_notification.notify_one();
}
bool empty() const
{
boost::mutex::scoped_lock lock(the_mutex);
return the_queue.empty();
}
size_t size() const
{
boost::mutex::scoped_lock lock(the_mutex);
return the_queue.size();
}
bool try_pop(T& popped_value)
{
boost::mutex::scoped_lock lock(the_mutex);
if (the_queue.empty()) {
return false;
}
popped_value = the_queue.front();
the_queue.pop();
lock.unlock();
the_tx_notification.notify_one();
return true;
}
void wait_and_pop(T& popped_value, size_t prebuffering = 1)
{
boost::mutex::scoped_lock lock(the_mutex);
while (the_queue.size() < prebuffering) {
the_rx_notification.wait(lock);
}
popped_value = the_queue.front();
the_queue.pop();
lock.unlock();
the_tx_notification.notify_one();
}
private:
std::queue<T> the_queue;
mutable boost::mutex the_mutex;
boost::condition_variable the_rx_notification;
boost::condition_variable the_tx_notification;
};
#endif
|
