AipsIO.h
Classes
- AipsIO -- AipsIO is the object persistency mechanism of AIPS++. (full description)
Interface
- Public Members
- AipsIO()
- explicit AipsIO (const String& fileName, String::OpenOption = String::Old, uInt filebufSize=65536)
- explicit AipsIO (ByteIO*)
- explicit AipsIO (TypeIO*)
- ~AipsIO()
- void open (const String& fileName, ByteIO::OpenOption = ByteIO::Old, uInt filebufSize=65536)
- void open (ByteIO*)
- void open (TypeIO*)
- void close()
- ByteIO::OpenOption fileOption() const
- uInt putstart (const String& objectType, uInt objectVersion)
- uInt putstart (const Char* objectType, uInt objectVersion)
- AipsIO& operator<< (const Bool& value)
- AipsIO& operator<< (const Char& value)
- AipsIO& operator<< (const uChar& value)
- AipsIO& operator<< (const short& value)
- AipsIO& operator<< (const unsigned short& value)
- AipsIO& operator<< (const int& value)
- AipsIO& operator<< (const unsigned int& value)
- AipsIO& operator<< (const Int64& value)
- AipsIO& operator<< (const uInt64& value)
- AipsIO& operator<< (const float& value)
- AipsIO& operator<< (const double& value)
- AipsIO& operator<< (const Complex& value)
- AipsIO& operator<< (const DComplex& value)
- AipsIO& operator<< (const String& value)
- AipsIO& operator<< (const Char* value)
- AipsIO& put (uInt nrval, const Bool* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const Char* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const uChar* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const short* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const unsigned short* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const int* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const unsigned int* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const Int64* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const uInt64* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const float* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const double* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const Complex* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const DComplex* values, Bool putNR = True)
- AipsIO& put (uInt nrval, const String* values, Bool putNR = True)
- uInt putend()
- Int64 getpos ()
- Int64 setpos (Int64 offset)
- const String& getNextType()
- uInt getstart (const String& objectType)
- uInt getstart (const Char* objectType)
- AipsIO& operator>> (Bool& value)
- AipsIO& operator>> (Char& value)
- AipsIO& operator>> (uChar& value)
- AipsIO& operator>> (short& value)
- AipsIO& operator>> (unsigned short& value)
- AipsIO& operator>> (int& value)
- AipsIO& operator>> (unsigned int& value)
- AipsIO& operator>> (Int64& value)
- AipsIO& operator>> (uInt64& value)
- AipsIO& operator>> (float& value)
- AipsIO& operator>> (double& value)
- AipsIO& operator>> (Complex& value)
- AipsIO& operator>> (DComplex& value)
- AipsIO& operator>> (String& value)
- AipsIO& get (uInt nrval, Bool* values)
- AipsIO& get (uInt nrval, Char* values)
- AipsIO& get (uInt nrval, uChar* values)
- AipsIO& get (uInt nrval, short* values)
- AipsIO& get (uInt nrval, unsigned short* values)
- AipsIO& get (uInt nrval, int* values)
- AipsIO& get (uInt nrval, unsigned int* values)
- AipsIO& get (uInt nrval, Int64* values)
- AipsIO& get (uInt nrval, uInt64* values)
- AipsIO& get (uInt nrval, float* values)
- AipsIO& get (uInt nrval, double* values)
- AipsIO& get (uInt nrval, Complex* values)
- AipsIO& get (uInt nrval, DComplex* values)
- AipsIO& get (uInt nrval, String* values)
- AipsIO& getnew (uInt& nrval, Bool*& values)
- AipsIO& getnew (uInt& nrval, Char*& values)
- AipsIO& getnew (uInt& nrval, uChar*& values)
- AipsIO& getnew (uInt& nrval, short*& values)
- AipsIO& getnew (uInt& nrval, unsigned short*& values)
- AipsIO& getnew (uInt& nrval, int*& values)
- AipsIO& getnew (uInt& nrval, unsigned int*& values)
- AipsIO& getnew (uInt& nrval, Int64*& values)
- AipsIO& getnew (uInt& nrval, uInt64*& values)
- AipsIO& getnew (uInt& nrval, float*& values)
- AipsIO& getnew (uInt& nrval, double*& values)
- AipsIO& getnew (uInt& nrval, Complex*& values)
- AipsIO& getnew (uInt& nrval, DComplex*& values)
- AipsIO& getnew (uInt& nrval, String*& values)
- uInt getend()
- Private Members
- void openInit (ByteIO::OpenOption)
- void testput()
- void testget()
- void testgetLength()
- void testputerr()
- void testgeterr()
- void testgeterrLength()
Review Status
- Reviewed By:
- ghunt
- Date Reviewed:
- 95Feb21
Etymology
AipsIO is simply the conventional shorthand for "aips++ input/output".
Synopsis
AipsIO is a class designed to do I/O for objects.
It reads/writes the data using a class derived from
TypeIO. For instance, class
CanonicalIO can be used
to read/write the data in canonical format.
The TypeIO class in its turn uses a class derived from
ByteIO to determine where the data
has to be written.
An object is written by writing all its data members. It will be
preceeded by a header containing type and version.
The I/O can be done via de overloaded << and >> operators to write or
read a single item (e.g., an int or an object). These operators are
already defined for all built-in data types and for Complex, DComplex,
String, and Bool.
Since each enumeration is a specific type, it is hard to handle them.
Casting to Bool (which is also an enumerated type) is a possibility,
but that assumes that each enumerated type has the same size (which
is probably true for all compilers).
Another possibility is to store it in an int when writing. Reading
can be done the opposite way, although the ARM says that an int
cannot be assigned to an enumerated type.
There are also functions put, get and getnew to write or read an
array of values. These functions are defined for the same data types
as << and >> (so one can write, for example, an array of Strings).
AipsIO.put (nr, arr) writes nr values from the given array.
AipsIO.get (nr, arr) reads nr values into the given user-supplied array.
AipsIO.getnew (&nr, &arr) reads the number of values written into
a new array allocated on the heap. It returns the nr of values read
and a pointer to the array.
The data must be read back in the same order as it was written.
The functions putstart(type,version)
and putend() must be called
before resp. after writing all values of the object.
It stores the given type and version of the object.
Similarly getstart(type) and getend() must be called.
getstart checks the type and returns the version. By using the version
the read function of the object can convert older versions of the
object (which may still reside on disk) to the latest version.
The function getNextType is available to get the type of the next
object stored. This can be used to check the type or to open (i.e.
issue a getstart) in the correct way.
When implementing a class, one should also define the operators << and >>
for the class to allow users to write or read an object in this
simple way (e.g., as io >> obj; to read an object).
One has to define the friend functions:
friend AipsIO& operator<< (AipsIO&, const YourClass&);
friend AipsIO& operator>> (AipsIO&, YourClass&);
since they cannot be stored in the class itself.
The type of an object is usually passed as the class name.
AipsIO& operator<< (AipsIO& ios, const YourClass& object) {
ios.putstart ("YourClass", version);
ios << ....;
ios.putend ();
}
The functions getpos() and setpos(offset) can be used to get and set
the offset in the file to a given point. They can be used to point
to a position in the file where an object must be written or read.
Obviously these functions are to be used by a storage manager and
are not for public use. Someday they should be made private with
a friend defined.
Example
MyClass myObject(...); // some object
AipsIO ios("file.name", ByteIO::New); // create new file
ios << myObject; // write object
MyClass myObject2;
ios >> myObject2; // read it back
This example creates an object, writes it to AipsIO and reads it
back into another object.
The shift functions for MyClass could be defined as follows:
AipsIO& operator<< (AipsIO& ios, const MyClass& myObject)
{
ios.putstart ("MyClass", 1); // MyClass version 1
ios << ...; // write all data members
ios.putend();
}
AipsIO& operator>> (AipsIO& ios, const MyClass& myObject)
{
// If needed, delete current data members first.
// Now read in the object.
uInt version = ios.getstart ("MyClass");
ios >> ...; // read all data members
ios.getend();
}
In this example the version is not used. In more complex objects
it will probably be used when data members get added or changed
in future versions of a software system.
Member Description
No file attached yet
explicit AipsIO (const String& fileName, String::OpenOption = String::Old, uInt filebufSize=65536)
Construct and open/create a file with the given name.
The actual IO is done via a TypeIO object using a filebuf
with a buffer of the given size.
explicit AipsIO (ByteIO*)
// uInt filebufSize=1048576);
Construct and open/create a file with the given name.
This can for instance by used to use AipsIO on a file descriptor
for which a FilebufIO
object has been created.
The actual IO is done via a CanonicalIO object on top of it.
explicit AipsIO (TypeIO*)
Construct and open by connecting to the given file descriptor.
The actual IO is done via a filebuf object with a buffer
of the given size.
Close if not done yet
void open (const String& fileName, ByteIO::OpenOption = ByteIO::Old, uInt filebufSize=65536)
Open/create file.
An exception is thrown if the object contains an already open file.
Open by connecting to the given byte stream.
This can for instance by used to use AipsIO on a file descriptor
for which a FilebufIO
object has been created.
The actual IO is done via a CanonicalIO object on top of it.
An exception is thrown if the object contains an already open file.
Open by connecting to the given file descriptor.
An exception is thrown if the object contains an already open file.
Close file opened
Return the file option.
uInt putstart (const String& objectType, uInt objectVersion)
uInt putstart (const Char* objectType, uInt objectVersion)
Start putting an object.
This writes the object type and version. When reading back getstart
calls have to be done in the same way. Getstart
checks the type and returns the version. The user can use that to
correctly read back objects with different versions.
Data in the outermost object cannot be put before a putstart is done.
Data in nested objects can be put without an intermediate putstart.
However, for complex objects it is recommended to do a putstart
to have a better checking.
After all values (inclusing nested objects) of the object have
been put, a call to putend has to be done.
AipsIO& operator<< (const Bool& value)
AipsIO& operator<< (const Char& value)
AipsIO& operator<< (const uChar& value)
AipsIO& operator<< (const short& value)
AipsIO& operator<< (const unsigned short& value)
AipsIO& operator<< (const int& value)
AipsIO& operator<< (const unsigned int& value)
AipsIO& operator<< (const Int64& value)
AipsIO& operator<< (const uInt64& value)
AipsIO& operator<< (const float& value)
AipsIO& operator<< (const double& value)
AipsIO& operator<< (const Complex& value)
AipsIO& operator<< (const DComplex& value)
AipsIO& operator<< (const String& value)
AipsIO& operator<< (const Char* value)
Put a single value.
AipsIO& put (uInt nrval, const Bool* values, Bool putNR = True)
AipsIO& put (uInt nrval, const Char* values, Bool putNR = True)
AipsIO& put (uInt nrval, const uChar* values, Bool putNR = True)
AipsIO& put (uInt nrval, const short* values, Bool putNR = True)
AipsIO& put (uInt nrval, const unsigned short* values, Bool putNR = True)
AipsIO& put (uInt nrval, const int* values, Bool putNR = True)
AipsIO& put (uInt nrval, const unsigned int* values, Bool putNR = True)
AipsIO& put (uInt nrval, const Int64* values, Bool putNR = True)
AipsIO& put (uInt nrval, const uInt64* values, Bool putNR = True)
AipsIO& put (uInt nrval, const float* values, Bool putNR = True)
AipsIO& put (uInt nrval, const double* values, Bool putNR = True)
AipsIO& put (uInt nrval, const Complex* values, Bool putNR = True)
AipsIO& put (uInt nrval, const DComplex* values, Bool putNR = True)
AipsIO& put (uInt nrval, const String* values, Bool putNR = True)
Put an array of values with the given number of values.
If the flag putNr is set, the number of values is put first.
End putting an object. It returns the object length (including
possible nested objects).
Int64 getpos ()
Int64 setpos (Int64 offset)
Get and set file-offset.
Get the type of the next object stored.
This is not possible if a put is in progress.
uInt getstart (const String& objectType)
uInt getstart (const Char* objectType)
Start reading an object. It will check if the given type matches
the one stored by putstart. It returns the object version which
can be used to read in older version of the object correctly.
After all values (inclusing nested objects) of the object have
been read, a call to getend has to be done.
AipsIO& operator>> (Bool& value)
AipsIO& operator>> (Char& value)
AipsIO& operator>> (uChar& value)
AipsIO& operator>> (short& value)
AipsIO& operator>> (unsigned short& value)
AipsIO& operator>> (int& value)
AipsIO& operator>> (unsigned int& value)
AipsIO& operator>> (Int64& value)
AipsIO& operator>> (uInt64& value)
AipsIO& operator>> (float& value)
AipsIO& operator>> (double& value)
AipsIO& operator>> (Complex& value)
AipsIO& operator>> (DComplex& value)
AipsIO& operator>> (String& value)
Get a single value.
AipsIO& get (uInt nrval, Bool* values)
AipsIO& get (uInt nrval, Char* values)
AipsIO& get (uInt nrval, uChar* values)
AipsIO& get (uInt nrval, short* values)
AipsIO& get (uInt nrval, unsigned short* values)
AipsIO& get (uInt nrval, int* values)
AipsIO& get (uInt nrval, unsigned int* values)
AipsIO& get (uInt nrval, Int64* values)
AipsIO& get (uInt nrval, uInt64* values)
AipsIO& get (uInt nrval, float* values)
AipsIO& get (uInt nrval, double* values)
AipsIO& get (uInt nrval, Complex* values)
AipsIO& get (uInt nrval, DComplex* values)
AipsIO& get (uInt nrval, String* values)
Read in nrval values into the user-supplied values buffer.
The buffer must be long enough.
AipsIO& getnew (uInt& nrval, Bool*& values)
AipsIO& getnew (uInt& nrval, Char*& values)
AipsIO& getnew (uInt& nrval, uChar*& values)
AipsIO& getnew (uInt& nrval, short*& values)
AipsIO& getnew (uInt& nrval, unsigned short*& values)
AipsIO& getnew (uInt& nrval, int*& values)
AipsIO& getnew (uInt& nrval, unsigned int*& values)
AipsIO& getnew (uInt& nrval, Int64*& values)
AipsIO& getnew (uInt& nrval, uInt64*& values)
AipsIO& getnew (uInt& nrval, float*& values)
AipsIO& getnew (uInt& nrval, double*& values)
AipsIO& getnew (uInt& nrval, Complex*& values)
AipsIO& getnew (uInt& nrval, DComplex*& values)
AipsIO& getnew (uInt& nrval, String*& values)
Read in values as written by the function put.
It will read the number of values (into nrval), allocate a
values buffer of that length and read the values into that buffer.
A pointer to the buffer is returned into values.
Although the buffer is allocated by this function,
the user has to delete it (using delete [] values;).
End reading an object. It returns the object length (including
possible nested objects).
It checks if the entire object has been read (to keep the data
stream in sync). If not, an exception is thrown.
Initialize everything for the open.
It checks if there is no outstanding open file.
Test if put is possible (throw exception if not).
Test if get is possible (throw exception if not).
Test if get did not exceed object.
Throw exception for testput
Throw exception for testget
Throw exception for testgetLength