rowreader.h
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1 /*
2  * Copyright (C) 2011 Tommi Maekitalo
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * As a special exception, you may use this file as part of a free
10  * software library without restriction. Specifically, if other files
11  * instantiate templates or use macros or inline functions from this
12  * file, or you compile this file and link it with other files to
13  * produce an executable, this file does not by itself cause the
14  * resulting executable to be covered by the GNU General Public
15  * License. This exception does not however invalidate any other
16  * reasons why the executable file might be covered by the GNU Library
17  * General Public License.
18  *
19  * This library is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22  * Lesser General Public License for more details.
23  *
24  * You should have received a copy of the GNU Lesser General Public
25  * License along with this library; if not, write to the Free Software
26  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27  */
28 
29 #ifndef TNTDB_ROWREADER_H
30 #define TNTDB_ROWREADER_H
31 
32 #include <tntdb/bits/row.h>
33 
34 namespace tntdb
35 {
68  class RowReader
69  {
70  const Row& row;
71  Row::size_type field_num;
72 
73  public:
75  explicit RowReader(const Row& row_, Row::size_type field_num_ = 0)
76  : row(row_),
77  field_num(field_num_)
78  { }
79 
85  template <typename T>
86  RowReader& get(T& ret)
87  { row[field_num++].get(ret); return *this; }
88 
92  template <typename T>
93  RowReader& get(T& ret, bool& nullInd)
94  { nullInd = row[field_num++].get(ret); return *this; }
95 
99  { v = row[field_num++]; return *this; }
100 
102  bool isNull() const
103  { return row[field_num].isNull(); }
104 
106  void rewind(Row::size_type n_ = 0)
107  { field_num = n_; }
108 
110  const Row& currentRow() const
111  { return row; }
112 
115  { return field_num; }
116 
119  { return ++field_num; }
120 
123  { return field_num++; }
124 
127  { return --field_num; }
128 
131  { return field_num--; }
132 
133  };
134 
136  { return RowReader(*this, n); }
137 
138  template <typename T>
139  RowReader Row::get(T& ret) const
140  { return RowReader(*this).get(ret); }
141 
142  template <typename T>
143  RowReader Row::get(T& ret, bool& nullInd) const
144  { return RowReader(*this).get(ret, nullInd); }
145 
146 }
147 
148 #endif // TNTDB_ROWREADER_H