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StorageOption.h
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1 //# StorageOption.h: Options defining how table files are organized
2 //# Copyright (C) 2014
3 //# Associated Universities, Inc. Washington DC, USA.
4 //#
5 //# This library is free software; you can redistribute it and/or modify it
6 //# under the terms of the GNU Library General Public License as published by
7 //# the Free Software Foundation; either version 2 of the License, or (at your
8 //# option) any later version.
9 //#
10 //# This library is distributed in the hope that it will be useful, but WITHOUT
11 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 //# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13 //# License for more details.
14 //#
15 //# You should have receied a copy of the GNU Library General Public License
16 //# along with this library; if not, write to the Free Software Foundation,
17 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18 //#
19 //# Correspondence concerning AIPS++ should be addressed as follows:
20 //# Internet email: aips2-request@nrao.edu.
21 //# Postal address: AIPS++ Project Office
22 //# National Radio Astronomy Observatory
23 //# 520 Edgemont Road
24 //# Charlottesville, VA 22903-2475 USA
25 //#
26 //# $Id: StorageOption.h 20859 2010-02-03 13:14:15Z gervandiepen $
27 
28 #ifndef TABLES_STORAGEOPTION_H
29 #define TABLES_STORAGEOPTION_H
30 
31 
32 //# Includes
33 #include <casacore/casa/aips.h>
34 
35 namespace casacore { //# NAMESPACE CASACORE - BEGIN
36 
37 // <summary>
38 // Options defining how table files are organized
39 // </summary>
40 
41 // <use visibility=export>
42 
43 // <reviewed reviewer="TPPR" date="08.11.94" tests="tTable.cc">
44 // </reviewed>
45 
46 // <synopsis>
47 // This class can be used to define how the files of a table are organized.
48 // There are two ways:
49 // <ol>
50 // <li> The old way where each storage manager has its own file(s).
51 // <li> Using MultiFile that storage managers can use to combine about all
52 // table files in a single file. This mode is particularly useful
53 // for new file systems (like Lustre) requiring large block sizes.
54 // <br>The block size to be used in a MultiFile can be defined in
55 // this class. Default is 4 MByte.
56 // <li> Using MultiHDF5 which behaves similar to MultiFile but uses an
57 // HDF5 file instead of a regular file. Note that it requires that
58 // support for HDF5 has been used in the build system.
59 // </ol>
60 // It is possible to specify the storage type and block size using aipsrc.
61 // The aipsrc variables are:
62 // <ul>
63 // <li> <src>table.storage.option</src>. The (case-insensitive) value can be
64 // 'multifile' or 'multihdf5'.
65 // Another value means the old way (separate files).
66 // <li> <src>table.storage.blocksize</src> gives the default blocksize to be
67 // used for the multifile and multihdf5 option.
68 // <li> <src>table.storage.odirect</src> can be true or false. It tells if the
69 // O_DIRECT option has to be used to let the kernel bypass its filecache
70 // for more predictable I/O behaviour. It's only used for MultiFile and
71 // only if the OS supports O_DIRECT.
72 // </ul>
73 // </synopsis>
74 
75 
77  {
78  public:
79  // Define the possible options how table files are organized.
80  enum Option {
81  // Let storage managers use a combined MultiFile.
83  // Let storage managers use a combined MultiHDF5.
85  // Let storage managers use separate files.
87  // Use default (currently SepFile).
89  // Use as defined in the aipsrc file.
91  };
92 
93  // Create an option object.
94  // The parameter values are described in the synopsis.
95  // The blocksize has to be given in bytes.
96  // A size value -2 means reading that size from the aipsrc file.
97  // A size value -1 means use the default of 4*1024*1024.
98  // <br>useODirect<0 means reading the option from the aipsrc file.
99  // It is only set if the OS supports O_DIRECT.
101 
102  // Fill the option in case Aipsrc or Default was given.
103  // It is done as explained in the synopsis.
104  void fillOption();
105 
106  // Get the option.
107  Option option() const
108  { return itsOption; }
109 
110  // Set the option.
112  { itsOption = option; }
113 
114  // Get the block size (in bytes).
115  uInt blockSize() const
116  { return itsBlockSize; }
117 
118  // Set the block size (in bytes).
120  { itsBlockSize = blockSize; }
121 
122  // Get the O_DIRECT option.
123  Bool useODirect() const
124  { return itsUseODirect; }
125 
126  // Set the O_DIRECT option.
127  // It is only set if the OS supports O_DIRECT.
129 
130  private:
135  };
136 
137 } //# NAMESPACE CASACORE - END
138 
139 #endif
int Int
Definition: aipstype.h:50
void setUseODirect(Bool useODirect)
Set the O_DIRECT option.
Use default (currently SepFile).
Definition: StorageOption.h:88
Let storage managers use separate files.
Definition: StorageOption.h:86
Let storage managers use a combined MultiHDF5.
Definition: StorageOption.h:84
Options defining how table files are organized.
Definition: StorageOption.h:76
Bool useODirect() const
Get the O_DIRECT option.
void setBlockSize(Int blockSize)
Set the block size (in bytes).
Option option() const
Get the option.
uInt blockSize() const
Get the block size (in bytes).
void setOption(Option option)
Set the option.
bool Bool
Define the standard types used by Casacore.
Definition: aipstype.h:42
Option
Define the possible options how table files are organized.
Definition: StorageOption.h:80
StorageOption(Option option=Aipsrc, Int blockSize=-2, Int useODirect=-3)
Create an option object.
Let storage managers use a combined MultiFile.
Definition: StorageOption.h:82
Class to read the casa general resource files.
Definition: Aipsrc.h:218
void fillOption()
Fill the option in case Aipsrc or Default was given.
unsigned int uInt
Definition: aipstype.h:51
#define casacore
&lt;X11/Intrinsic.h&gt; #defines true, false, casacore::Bool, and String.
Definition: X11Intrinsic.h:42