-\section{Streams in wxWindows overview}\label{wxstreamoverview}
+\section{wxStreams overview}\label{wxstreamoverview}
Classes: \helpref{wxStreamBase}{wxstreambase},
\helpref{wxStreamBuffer}{wxstreambuffer}, \helpref{wxInputStream}{wxinputstream},
\wxheading{Purpose of wxStream}
-We went into troubles with c++ std streams on some platform:
-they react quite well in most cases, but in multi-threaded case, for example,
-they have a LOT of problems.
+We had troubles with standard C++ streams on several platforms:
+they react quite well in most cases, but in the multi-threaded case, for example,
+they have many problems. Some Borland Compilers refuse to work at all
+with them and using iostreams on Linux makes writing programs, that are
+binary compatible across different Linux distributions, impossible.
-Then, wxStreams have been built in wxWindows because an application should compile
-and run on all supported platforms and we don't want users depend on release
+Therefore, wxStreams have been added to wxWidgets because an application should
+compile and run on all supported platforms and we don't want users to depend on release
X.XX of libg++ or some other compiler to run the program.
wxStreams is divided in two main parts:
+
\begin{enumerate}\itemsep=0pt
\item the core: wxStreamBase, wxStreamBuffer, wxInputStream, wxOutputStream,
wxFilterIn/OutputStream
\end{enumerate}
wxStreamBase is the base definition of a stream. It defines, for example,
-the API of OnSysRead, OnSysWrite, OnSysSeek and OnSysTell. These functions are
+the API of OnSysRead, OnSysWrite, OnSysSeek and OnSysTell. These functions
are really implemented by the "IO" classes.
wxInputStream and wxOutputStream inherit from it.
SeekI (I for Input), and all read or IO generic related functions.
wxOutputStream does the same thing but it is for write-only streams.
-wxFilterIn/OutputStream is base class definition for stream filtering.
-I mean by stream filtering, a stream which does no syscall but filter datas
+wxFilterIn/OutputStream is the base class definition for stream filtering.
+Stream filtering means a stream which does no syscall but filters data
which are passed to it and then pass them to another stream.
For example, wxZLibInputStream is an inline stream decompressor.
\wxheading{Generic usage: an example}
-About its usage, it's simple. We can take the example of wxFileInputStream and here is a sample
+Usage is simple. We can take the example of wxFileInputStream and here is some sample
code:
\begin{verbatim}
...
// The constructor initializes the stream buffer and open the file descriptor
// associated to the name of the file.
- wxFileInputStream in\_stream("the\_file\_to\_be\_read");
+ wxFileInputStream in_stream("the_file_to_be_read");
- // Ok, read some bytes ... nb\_datas is expressed in bytes.
- in\_stream.Read(data, nb\_datas);
- if (in\_stream.LastError() != wxStream\_NOERROR) {
+ // Ok, read some bytes ... nb_datas is expressed in bytes.
+ in_stream.Read(data, nb_datas);
+ if (in_stream.LastError() != wxSTREAM_NOERROR) {
// Oh oh, something bad happens.
// For a complete list, look into the documentation at wxStreamBase.
}
// You can also inline all like this.
- if (in\_stream.Read(data, nb\_datas).LastError() != wxStream\_NOERROR) {
+ if (in_stream.Read(data, nb_datas).LastError() != wxSTREAM_NOERROR) {
// Do something.
}
// You can also get the last number of bytes REALLY put into the buffer.
- size\_t really\_read = in\_stream.LastRead();
+ size_t really_read = in_stream.LastRead();
// Ok, moves to the beginning of the stream. SeekI returns the last position
// in the stream counted from the beginning.
- off\_t old_position = in\_stream.SeekI(0, wxFromBeginning);
+ off_t old_position = in_stream.SeekI(0, wxFromBeginning);
// What is my current position ?
- off\_t position = in\_stream.TellI();
+ off_t position = in_stream.TellI();
// wxFileInputStream will close the file descriptor on the destruction.
\end{verbatim}
-\wxheading{Compatibility with c++ stream}
+\wxheading{Compatibility with C++ streams}
As I said previously, we could add a filter stream so it takes an istream
argument and builds a wxInputStream from it: I don't think it should
-be difficult to implement it and it may be available in the fix of wxWindows 2.0.
+be difficult to implement it and it may be available in the fix of wxWidgets 2.0.