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TypeIO.h
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1 //# TypeIO.h: Abstract base class for IO of data in a type-dependent format
2 //# Copyright (C) 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_TYPEIO_H
29 #define CASA_TYPEIO_H
30 
31 #include <casacore/casa/aips.h>
34 //# The following should be a forward declaration. But our Complex & DComplex
35 //# classes are a typedef hence this does not work. Replace the following with
36 //# forward declarations when Complex and DComplex are no longer typedefs.
38 
39 namespace casacore { //# NAMESPACE CASACORE - BEGIN
40 
41 class String;
42 
43 // <summary>Abstract base class for IO of data in a type-dependent format</summary>
44 
45 // <use visibility=export>
46 
47 // <reviewed reviewer="Friso Olnon" date="1996/11/06" tests="tTypeIO" demos="">
48 // </reviewed>
49 
50 // <prerequisite>
51 // <li> <linkto class=ByteIO>ByteIO</linkto> class and derived classes
52 // </prerequisite>
53 
54 // <synopsis>
55 // This class is the abstract base class for doing IO in a type-dependent
56 // way. Derived from it are classes like <linkto class=CanonicalIO>
57 // CanonicalIO</linkto> doing the actual formatting of the data.
58 // <p>
59 // The TypeIO classes convert the data to/from the given format
60 // using the static conversion functions in the classes like
61 // <linkto class=CanonicalConversion>CanonicalConversion</linkto>.
62 // The data is written to or read from the <linkto class=ByteIO>ByteIO</linkto>
63 // object given when constructing the TypeIO object.
64 // <p>
65 // TypeIO declares the virtual functions read and write to read/write
66 // one or more values of a given data type. Usually the derived classes
67 // have to implement these functions. An exception are the functions
68 // handling Bool, complex and String values. These functions have a
69 // default implementation in this base class. However, if needed
70 // they can be overwritten in derived classes.
71 // </synopsis>
72 
73 // <motivation>
74 // The base class is needed for polymorphic type-dependent IO.
75 // Furthermore the common functionality can be implemented here.
76 // </motivation>
77 
78 
79 class TypeIO
80 {
81 public:
82  // Constructor.
83  // The read/write functions will use the given ByteIO object
84  // as the data store.
85  explicit TypeIO (ByteIO* byteIO, Bool takeOver=False);
86 
87  virtual ~TypeIO();
88 
89  // Functions to return a reference to the ByteIO class.
90  // <group>
91  const ByteIO& byteIO() const;
92  ByteIO& byteIO();
93  // </group>
94 
95  // Convert the values and write them to the ByteIO object.
96  // By default Bools are stored as bits, Complex as 2 floats,
97  // DComplex as 2 doubles and String as a length (uInt) and chars.
98  // If it does not succeed an exception will be thrown.
99  // <group>
100  virtual size_t write (size_t nvalues, const Bool* value);
101  virtual size_t write (size_t nvalues, const Char* value) = 0;
102  virtual size_t write (size_t nvalues, const uChar* value) = 0;
103  virtual size_t write (size_t nvalues, const Short* value) = 0;
104  virtual size_t write (size_t nvalues, const uShort* value) = 0;
105  virtual size_t write (size_t nvalues, const Int* value) = 0;
106  virtual size_t write (size_t nvalues, const uInt* value) = 0;
107  virtual size_t write (size_t nvalues, const Int64* value) = 0;
108  virtual size_t write (size_t nvalues, const uInt64* value) = 0;
109  virtual size_t write (size_t nvalues, const Float* value) = 0;
110  virtual size_t write (size_t nvalues, const Double* value) = 0;
111  virtual size_t write (size_t nvalues, const Complex* value);
112  virtual size_t write (size_t nvalues, const DComplex* value);
113  virtual size_t write (size_t nvalues, const String* value);
114  // </group>
115 
116  // Read the values from the ByteIO object and convert them.
117  // By default Bools are stored as bits, Complex as 2 floats,
118  // DComplex as 2 doubles and String as a length (uInt) and chars.
119  // If it does not succeed an exception will be thrown.
120  // <group>
121  virtual size_t read (size_t nvalues, Bool* value);
122  virtual size_t read (size_t nvalues, Char* value) = 0;
123  virtual size_t read (size_t nvalues, uChar* value) = 0;
124  virtual size_t read (size_t nvalues, Short* value) = 0;
125  virtual size_t read (size_t nvalues, uShort* value) = 0;
126  virtual size_t read (size_t nvalues, Int* value) = 0;
127  virtual size_t read (size_t nvalues, uInt* value) = 0;
128  virtual size_t read (size_t nvalues, Int64* value) = 0;
129  virtual size_t read (size_t nvalues, uInt64* value) = 0;
130  virtual size_t read (size_t nvalues, Float* value) = 0;
131  virtual size_t read (size_t nvalues, Double* value) = 0;
132  virtual size_t read (size_t nvalues, Complex* value);
133  virtual size_t read (size_t nvalues, DComplex* value);
134  virtual size_t read (size_t nvalues, String* value);
135  // </group>
136 
137  // This function sets the position on the given offset.
138  // The seek option defines from which file position the seek is done.
139  // -1 is returned if not seekable.
140  // <group>
143  // </group>
144 
145  // Is the TypeIO stream readable?
146  Bool isReadable() const;
147 
148  // Is the TypeIO stream writable?
149  Bool isWritable() const;
150 
151  // Is the TypeIO stream seekable?
152  Bool isSeekable() const;
153 
154 protected:
155  // This variable keeps a pointer to a ByteIO.
157 
158  // The copy constructor uses reference semantics.
159  TypeIO (const TypeIO& TypeIO);
160 
161  // The assignment operator uses reference semantics.
162  TypeIO& operator= (const TypeIO& typeIO);
163 };
164 
165 
166 
167 
168 } //# NAMESPACE CASACORE - END
169 
170 #endif
long long Int64
Define the extra non-standard types used by Casacore (like proposed uSize, Size)
Definition: aipsxtype.h:38
int Int
Definition: aipstype.h:50
Bool isReadable() const
Is the TypeIO stream readable?
SeekOption
Define the possible seek options.
Definition: ByteIO.h:82
Int64 seek(Int64 offset, ByteIO::SeekOption=ByteIO::Begin)
This function sets the position on the given offset.
TypeIO(ByteIO *byteIO, Bool takeOver=False)
Constructor.
unsigned long long uInt64
Definition: aipsxtype.h:39
unsigned char uChar
Definition: aipstype.h:47
char Char
Definition: aipstype.h:46
virtual size_t read(size_t nvalues, Bool *value)
Read the values from the ByteIO object and convert them.
short Short
Definition: aipstype.h:48
const ByteIO & byteIO() const
Functions to return a reference to the ByteIO class.
Referenced counted pointer for constant data.
Definition: VisModelData.h:42
double Double
Definition: aipstype.h:55
Abstract base class for IO on a byte stream.
Definition: ByteIO.h:61
Abstract base class for IO of data in a type-dependent format.
Definition: TypeIO.h:79
Bool isWritable() const
Is the TypeIO stream writable?
TypeIO & operator=(const TypeIO &typeIO)
The assignment operator uses reference semantics.
virtual size_t write(size_t nvalues, const Bool *value)
Convert the values and write them to the ByteIO object.
bool Bool
Define the standard types used by Casacore.
Definition: aipstype.h:42
Seek from beginning of file.
Definition: ByteIO.h:84
Bool isSeekable() const
Is the TypeIO stream seekable?
float Float
Definition: aipstype.h:54
const Bool False
Definition: aipstype.h:44
virtual ~TypeIO()
String: the storage and methods of handling collections of characters.
Definition: String.h:223
CountedPtr< ByteIO > itsByteIO
This variable keeps a pointer to a ByteIO.
Definition: TypeIO.h:156
LatticeExprNode value(const LatticeExprNode &expr)
This function returns the value of the expression without a mask.
unsigned int uInt
Definition: aipstype.h:51
unsigned short uShort
Definition: aipstype.h:49
#define casacore
&lt;X11/Intrinsic.h&gt; #defines true, false, casacore::Bool, and String.
Definition: X11Intrinsic.h:42