LSSTApplications  1.1.2+25,10.0+13,10.0+132,10.0+133,10.0+224,10.0+41,10.0+8,10.0-1-g0f53050+14,10.0-1-g4b7b172+19,10.0-1-g61a5bae+98,10.0-1-g7408a83+3,10.0-1-gc1e0f5a+19,10.0-1-gdb4482e+14,10.0-11-g3947115+2,10.0-12-g8719d8b+2,10.0-15-ga3f480f+1,10.0-2-g4f67435,10.0-2-gcb4bc6c+26,10.0-28-gf7f57a9+1,10.0-3-g1bbe32c+14,10.0-3-g5b46d21,10.0-4-g027f45f+5,10.0-4-g86f66b5+2,10.0-4-gc4fccf3+24,10.0-40-g4349866+2,10.0-5-g766159b,10.0-5-gca2295e+25,10.0-6-g462a451+1
LSSTDataManagementBasePackage
Fifo.h
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1 // -*- lsst-c++ -*-
2 
3 /*
4  * LSST Data Management System
5  * Copyright 2008, 2009, 2010 LSST Corporation.
6  *
7  * This product includes software developed by the
8  * LSST Project (http://www.lsst.org/).
9  *
10  * This program is free software: you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation, either version 3 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the LSST License Statement and
21  * the GNU General Public License along with this program. If not,
22  * see <http://www.lsstcorp.org/LegalNotices/>.
23  */
24 
25 
33 #ifndef LSST_AP_FIFO_H
34 #define LSST_AP_FIFO_H
35 
36 #include "boost/noncopyable.hpp"
37 #include "boost/static_assert.hpp"
38 
39 #include "lsst/pex/exceptions.h"
40 
41 #include "Common.h"
42 
43 
44 namespace lsst { namespace ap {
45 
47 template <int NumEntries>
48 class Fifo : private boost::noncopyable {
49 
50  // NumEntries must be a positive power of 2
51  BOOST_STATIC_ASSERT(NumEntries > 0 && (NumEntries & (NumEntries - 1)) == 0);
52 
53 public :
54 
56  Fifo() { clear(); }
57 
59  void clear() {
60  _size = 0;
61  _back = 0;
62  _front = 0;
63  }
64 
66  bool empty() const {
67  return _size == 0;
68  }
69 
71  bool full() const {
72  return _size == NumEntries;
73  }
74 
80  void enqueue(boost::int64_t const elt) {
81  int sz = _size;
82  if (sz == NumEntries) {
83  throw LSST_EXCEPT(lsst::pex::exceptions::LengthError,
84  "unable to insert element into full FIFO");
85  }
86  int i = _back;
87  _buffer[i] = elt;
88  _back = (i + 1) & (NumEntries - 1);
89  _size = sz + 1;
90  }
91 
97  boost::int64_t dequeue() {
98  int sz = _size;
99  if (sz == 0) {
100  throw LSST_EXCEPT(lsst::pex::exceptions::LengthError,
101  "unable to remove element from empty FIFO");
102  }
103  int i = _front;
104  boost::int64_t elt = _buffer[i];
105  _front = (i + 1) & (NumEntries - 1);
106  _size = sz - 1;
107  return elt;
108  }
109 
110 private :
111 
112  boost::int64_t _buffer[NumEntries];
113  int _size;
114  int _back;
115  int _front;
116 };
117 
118 
119 }} // end of namespace lsst::ap
120 
121 #endif // LSST_AP_FIFO_H
lsst::ap::Fifo::dequeue
boost::int64_t dequeue()
Definition: Fifo.h:97
lsst::ap::Fifo::enqueue
void enqueue(boost::int64_t const elt)
Definition: Fifo.h:80
lsst::ap::Fifo::clear
void clear()
Empties the Fifo.
Definition: Fifo.h:59
lsst::ap::Fifo::BOOST_STATIC_ASSERT
BOOST_STATIC_ASSERT(NumEntries > 0 &&(NumEntries &(NumEntries-1))==0)
lsst::ap::Fifo::_size
int _size
Definition: Fifo.h:113
lsst::ap::Fifo::full
bool full() const
Returns true if the Fifo is full.
Definition: Fifo.h:71
lsst::ap::Fifo::_front
int _front
Definition: Fifo.h:115
lsst::ap::Fifo
A First In, First Out (FIFO) queue of fixed capacity.
Definition: Fifo.h:48
lsst::ap::Fifo::_buffer
boost::int64_t _buffer[NumEntries]
Definition: Fifo.h:112
Common.h
Master header file for the association pipeline.
lsst::ap::Fifo::empty
bool empty() const
Returns true if the Fifo is empty.
Definition: Fifo.h:66
LSST_EXCEPT
#define LSST_EXCEPT(type,...)
Definition: Exception.h:46
lsst::ap::Fifo::Fifo
Fifo()
Creates an empty Fifo.
Definition: Fifo.h:56
lsst::ap::Fifo::_back
int _back
Definition: Fifo.h:114
exceptions.h
Include files required for standard LSST Exception handling.
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