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da0e9ce3 | 1 | /******************************************************************************* |
2 | * Project: BaBar detector at the SLAC PEP-II B-factory | |
3 | * Package: EvtGenBase | |
4 | * File: $Id: EvtStreamInputIterator.hh,v 1.1 2003/03/03 05:38:22 dvoretsk Exp $ | |
5 | * Author: Alexei Dvoretskii, dvoretsk@slac.stanford.edu, 2001-2002 | |
6 | * | |
7 | * Copyright (C) 2002 Caltech | |
8 | *******************************************************************************/ | |
9 | ||
10 | // Adapters are used to convert various types of input streams | |
11 | // into an iteratable interface. | |
12 | ||
13 | #ifndef EVT_STREAM_INPUT_ITERATOR_HH | |
14 | #define EVT_STREAM_INPUT_ITERATOR_HH | |
15 | ||
16 | #include "EvtGenBase/EvtStreamAdapter.hh" | |
17 | #include <iterator> | |
18 | using std::input_iterator_tag; | |
19 | ||
20 | template <class Point> | |
21 | class EvtStreamInputIterator { | |
22 | public: | |
23 | ||
24 | typedef input_iterator_tag iterator_category; | |
25 | typedef Point value_type; | |
26 | typedef ptrdiff_t difference_type; | |
27 | typedef const Point* pointer; | |
28 | typedef const Point& reference; | |
29 | ||
30 | EvtStreamInputIterator() | |
31 | : _counter(0) | |
32 | {} | |
33 | ||
34 | EvtStreamInputIterator(const EvtStreamInputIterator& other) | |
35 | : _counter(other._counter ? other._counter->clone() : 0), | |
36 | _currentValue(other._currentValue) | |
37 | {} | |
38 | ||
39 | EvtStreamInputIterator(EvtStreamAdapter<Point>& counter) | |
40 | : _counter(counter.clone()) | |
41 | { | |
42 | _currentValue = _counter->currentValue(); | |
43 | } | |
44 | ||
45 | ~EvtStreamInputIterator() | |
46 | { | |
47 | if(_counter) delete _counter; | |
48 | } | |
49 | ||
50 | reference operator*() const | |
51 | { | |
52 | return _currentValue; | |
53 | } | |
54 | ||
55 | EvtStreamInputIterator& operator++() | |
56 | { | |
57 | _read(); | |
58 | return *this; | |
59 | } | |
60 | ||
61 | EvtStreamInputIterator operator++(int) | |
62 | { | |
63 | EvtStreamInputIterator tmp = *this; | |
64 | _read(); | |
65 | return tmp; | |
66 | } | |
67 | ||
68 | bool operator==(const EvtStreamInputIterator& other) const | |
69 | { | |
70 | // Equality is only defined for two past the end iterators | |
71 | return (pastEnd() && other.pastEnd()); | |
72 | } | |
73 | ||
74 | protected: | |
75 | ||
76 | EvtStreamAdapter<Point>* _counter; | |
77 | value_type _currentValue; | |
78 | ||
79 | bool pastEnd() const | |
80 | { | |
81 | bool ret = true; | |
82 | if(_counter) ret = _counter->pastEnd(); | |
83 | return ret; | |
84 | } | |
85 | ||
86 | // Advances the iterator | |
87 | ||
88 | void _read() { | |
89 | ||
90 | _counter->advance(); | |
91 | _currentValue = _counter->currentValue(); | |
92 | } | |
93 | }; | |
94 | ||
95 | ||
96 | // For adaptable generators these shorthand functions can be used | |
97 | // to construct iterators. | |
98 | ||
99 | template <class Generator> | |
100 | EvtStreamInputIterator<typename Generator::result_type> iter(Generator gen, int N = 0) | |
101 | { | |
102 | typedef typename Generator::result_type Point; | |
103 | EvtGenStreamAdapter<Point,Generator> counter(gen,N); | |
104 | return EvtStreamInputIterator<Point>(counter); | |
105 | } | |
106 | ||
107 | ||
108 | #endif | |
109 | ||
110 | ||
111 |