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IO.h
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1//# IO.h: Basic classes and global functions for IO and object persistency
2//# Copyright (C) 1995,1996,1999,2001
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 received 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//# $Id$
27
28#ifndef CASA_IO_H
29#define CASA_IO_H
30
31#include <casacore/casa/aips.h>
32
33//# Includes for object persistency.
34#include <casacore/casa/IO/AipsIO.h>
35#include <casacore/casa/IO/AipsIOCarray.h>
36
37//# Includes for general IO.
38#include <casacore/casa/IO/ByteSinkSource.h>
39
40//# Includes for underlying IO classes.
41#include <casacore/casa/IO/CanonicalIO.h>
42#include <casacore/casa/IO/RawIO.h>
43#include <casacore/casa/IO/RegularFileIO.h>
44#include <casacore/casa/IO/FilebufIO.h>
45#include <casacore/casa/IO/FiledesIO.h>
46#include <casacore/casa/IO/MemoryIO.h>
47#include <casacore/casa/IO/MFFileIO.h>
48
49
50namespace casacore { //# NAMESPACE CASACORE - BEGIN
51
52// <module>
53
54// <summary>
55// Basic classes and global functions for IO and object persistency
56// </summary>
57
58// <reviewed reviewer="UNKNOWN" date="before2004/08/25" demos="">
59// </reviewed>
60
61// <synopsis>
62// This module provides the basic IO functionality for the Casacore classes.
63// There are two IO mechanisms:
64// <ol>
65// <li> Class <linkto class=AipsIO:description>AipsIO</linkto>
66// provides the object persistency mechanism.
67// The templated global functions in
68// <linkto file="AipsIOCarray.h#AipsIOCarray">AipsIOCarray.h</linkto>
69// form a little layer upon AipsIO. They provide the means to put or
70// get a C-style array of any type.
71// <li> Class <linkto class=ByteSinkSource:description>ByteSinkSource</linkto>
72// and its ancestors provide a general IO mechanism.
73// </ol>
74//
75// Both use the underlying IO framework which define where and how
76// the data are written. The how-part is defined by classes derived from
77// <linkto class=TypeIO:description>TypeIO</linkto> as shown
78// in the <a href=IO-framework.drawio.svg.html>UML diagram</a>.
79// There are three such classes:
80// <ol>
81// <li> <linkto class=CanonicalIO:description>CanonicalIO</linkto> reads/writes
82// data in canonical (machine-independent) format. This should be
83// used when data are meant to be exportable.
84// It uses the conversion functions in class
85// <linkto class=CanonicalConversion:description>CanonicalConversion
86// </linkto>.
87// <li> <linkto class=RawIO:description>RawIO</linkto> reads/writes
88// data in native (machine-dependent) format. This can be used when
89// data are not exported.
90// <li> <linkto class=ConversionIO:description>ConversionIO</linkto>
91// reads/writes in an external format as defined at construction time.
92// This can be used when the external format can be one of several
93// (e.g. VAX or IBM for a WSRT archive tape). In this way the
94// format has to be defined only once and thereafter is it handled
95// correctly by the polymorphism mechanism.
96// </ol>
97// The where-part is defined by classes derived from
98// <linkto class=ByteIO:description>ByteIO</linkto> as shown
99// in the <a href=IO-framework.drawio.svg.html>UML diagram</a>.
100// There are a few such classes:
101// <ol>
102// <li> <linkto class=RegularFileIO:description>RegularFileIO</linkto> uses a
103// regular file to hold the data. Internally it uses FilebufIO (see below).
104// It can handle files > 2 GB.
105// <li> <linkto class=FilebufIO:description>FilebufIO</linkto> does the IO
106// in a buffered way similar to the <src>stdio</src> system. However, it
107// does not use stdio because that gave problems when doing concurrent
108// access from multiple processes.
109// It can handle files > 2 GB.
110// <li> <linkto class=FiledesIO:description>FiledesIO</linkto> uses the
111// UNIX IO-functions like <src>open, read</src> to do IO directly.
112// It does not use an internal buffer. Instead it always does
113// physical IO. It is meant for IO operations where large chunks of
114// a file are accessed and for IO on sockets, pipes, etc..
115// It can handle files > 2 GB.
116// <li> <linkto class=StreamIO:description>StreamIO</linkto> for IO
117// on a socket.
118// <li> <linkto class=TapeIO:description>TapeIO</linkto> for IO on a tape
119// device.
120// <li> <linkto class=MemoryIO:description>MemoryIO</linkto> uses a
121// (possibly expandable) buffer in memory to hold the data.
122// <li> <linkto class=MMapIO:description>MMapIO</linkto> uses memory-mapped IO.
123// Be careful to use this on 32-bit machines, because its address space is
124// too small to handle a file of a few GBytes.
125// <li> <linkto class=MFFileIO:description>MFFileIO</linkto> uses a virtual
126// file in a <linkto class=MultiFile:description>MultiFile</linkto>
127// container file. MultiFile is meant to combine multiple files in
128// a single physical file to reduce the number of files used by
129// the Casacore table system.
130// </ol>
131//
132// The IO framework is easily expandable. One can for instance think of a
133// class <src>AsciiIO</src> derived from <src>TypeIO</src>
134// to hold data in ASCII format.
135// A class <src>RemoteTapeIO</src> could be developed for IO on a tape
136// device on another node.
137// </synopsis>
138
139// </module>
140
141
142
143} //# NAMESPACE CASACORE - END
144
145#endif
146
this file contains all the compiler specific defines
Definition mainpage.dox:28