data.h
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1 /*
2  * Copyright (C) 2003 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 
30 #ifndef TNT_DATA_H
31 #define TNT_DATA_H
32 
33 #include <iostream>
34 
36 namespace tnt
37 {
38  class DataChunk
39  {
40  const char* _data;
41  unsigned _len;
42 
43  public:
44  DataChunk(const char* data, const char* end)
45  : _data(data),
46  _len(static_cast<unsigned>(end - data))
47  { }
48  DataChunk(const char* data, unsigned len)
49  : _data(data),
50  _len(len)
51  { }
52 
53  const char* getData() const { return _data; }
54  unsigned getLength() const { return _len; }
55  };
56 
58  // interpretes raw data as a data-structure with chunks
59  // unsigned: number of chunks
60  // count X unsigned: offsets
61  // data
62  //
63  class DataChunks
64  {
65  const char* _dataObject;
66 
67  const unsigned* udata() const
68  {
69  const char* d = _dataObject;
70  return reinterpret_cast<const unsigned*>(d);
71  }
72 
73  public:
74  DataChunks(const char* d = 0)
75  : _dataObject(d)
76  { }
77 
78  const char* data() const
79  { return _dataObject; }
80 
81  void setData(const char* d)
82  { _dataObject = d; }
83 
84  // number of chunks
85  unsigned size() const
86  { return (udata()[0] / sizeof(unsigned)) - 1; }
87 
88  // offset of n-th chunk from start
89  unsigned offset(unsigned n) const
90  { return udata()[n] - udata()[0]; }
91 
92  // size of nth chunk in bytes
93  unsigned size(unsigned n) const
94  { return udata()[n + 1] - udata()[n]; }
95 
96  // pointer to n-th chunk
97  const char* ptr(unsigned n) const
98  {
99  const char* d = _dataObject;
100  return d + udata()[n];
101  }
102 
103  DataChunk operator[] (unsigned n) const
104  { return DataChunk(ptr(n), size(n)); }
105  };
106 
107  inline std::ostream& operator << (std::ostream& out, const DataChunk& c)
108  {
109  out.write(c.getData(), c.getLength());
110  return out;
111  }
112 }
114 
115 #endif // TNT_DATA_H
116