wxStreamBase Class Reference

#include <wx/stream.h>

Inheritance diagram for wxStreamBase:

Detailed Description

This class is the base class of most stream related classes in wxWidgets.

It must not be used directly.

Library:  wxBase

Category:  Streams

See Also

wxStreamBuffer

Public Member Functions
	wxStreamBase ()
	Creates a dummy stream object.
virtual	~wxStreamBase ()
	Destructor.
wxStreamError	GetLastError () const
	This function returns the last error.
virtual wxFileOffset	GetLength () const
	Returns the length of the stream in bytes.
virtual size_t	GetSize () const
	This function returns the size of the stream.
virtual bool	IsOk () const
	Returns true if no error occurred on the stream.
virtual bool	IsSeekable () const
	Returns true if the stream supports seeking to arbitrary offsets.
void	Reset (wxStreamError error=wxSTREAM_NO_ERROR)
	Resets the stream state.
bool	operator! () const
	Returns the opposite of IsOk().

Protected Member Functions
virtual wxFileOffset	OnSysSeek (wxFileOffset pos, wxSeekMode mode)
	Internal function.
virtual wxFileOffset	OnSysTell () const
	Internal function.

Constructor & Destructor Documentation

wxStreamBase::wxStreamBase

(

)

Creates a dummy stream object.

It doesn't do anything.

virtual wxStreamBase::~wxStreamBase ( )

virtual

Destructor.

Member Function Documentation

wxStreamError wxStreamBase::GetLastError

(

)

const

This function returns the last error.

virtual wxFileOffset wxStreamBase::GetLength ( ) const

virtual

Returns the length of the stream in bytes.

If the length cannot be determined (this is always the case for socket streams for example), returns wxInvalidOffset.

Since

2.5.4

Reimplemented in wxCountingOutputStream.

virtual size_t wxStreamBase::GetSize ( ) const

virtual

This function returns the size of the stream.

For example, for a file it is the size of the file.

Warning

There are streams which do not have size by definition, such as socket streams. In that cases, GetSize() returns 0 so you should always test its return value.

virtual bool wxStreamBase::IsOk ( ) const

virtual

Returns true if no error occurred on the stream.

See Also

GetLastError()

Reimplemented in wxFSInputStream, wxFileStream, wxFFileStream, wxFFileInputStream, wxFileInputStream, wxFileOutputStream, and wxFFileOutputStream.

virtual bool wxStreamBase::IsSeekable ( ) const

virtual

Returns true if the stream supports seeking to arbitrary offsets.

virtual wxFileOffset wxStreamBase::OnSysSeek ( wxFileOffset  pos, wxSeekMode  mode  )

protectedvirtual

Internal function.

It is called when the stream needs to change the current position.

Parameters

pos	Offset to seek to.
mode	One of the wxSeekMode enumeration values.

Returns

The new stream position or wxInvalidOffset on error.

virtual wxFileOffset wxStreamBase::OnSysTell ( ) const

protectedvirtual

Internal function.

It is called when the stream needs to know the real position.

Returns

The current stream position.

bool wxStreamBase::operator!

(

)

const

Returns the opposite of IsOk().

You can use this function to test the validity of the stream as if it was a pointer:

bool DoSomething(wxInputStream& stream)
{
    wxInt32 data;
    if (!stream.Read(&data, 4))
        return false;
    ...
}

void wxStreamBase::Reset

(

wxStreamError

error = wxSTREAM_NO_ERROR

)

Resets the stream state.

By default, resets the stream to good state, i.e. clears any errors. Since wxWidgets 2.9.3 can be also used to explicitly set the state to the specified error (the error argument didn't exist in the previous versions).

See Also

GetLastError()