-\section{\class{wxStreamBuffer}}\label{wxstreambuf}
+\section{\class{wxStreamBuffer}}\label{wxstreambuffer}
+
+\wxheading{Derived from}
+
+None
+
+\wxheading{Include files}
+
+<wx/stream.h>
\wxheading{See also}
+
\helpref{wxStreamBase}{wxstreambase}
% ---------------------------------------------------------------------------
% Members
% ---------------------------------------------------------------------------
-
\latexignore{\rtfignore{\wxheading{Members}}}
% -----------
% ctor & dtor
% -----------
+\membersection{wxStreamBuffer::wxStreamBuffer}\label{wxstreambufconst}
-\membersection{wxStreamBuffer::wxStreamBuffer}
-\func{}{wxStreamBuffer}{\param{wxStreamBase&}{ stream}, \param{BufMode}{ mode}}
+\func{}{wxStreamBuffer}{\param{wxStreamBase\&}{ stream}, \param{BufMode}{ mode}}
Constructor, creates a new stream buffer using \it{stream} as a parent stream
and \it{mode} as the IO mode. \it{mode} can be: wxStreamBuffer::read,
-wxStreamBuffer::write, wxStreamBuffer::read_write.
+wxStreamBuffer::write, wxStreamBuffer::read\_write.
+One stream can have many stream buffers but only one is used internally to
+pass IO call (e.g. wxInputStream::Read() -> wxStreamBuffer::Read()). But you
+can call directly wxStreamBuffer::Read without any problems.
+
+\wxheading{Warning}
+
+All errors and messages linked to the stream are stored in the stream object.
+\begin{verbatim}
+ streambuffer.Read(...);
+ streambuffer2.Read(...); /* This one erases previous error messages set by
+ ``streambuffer'' */
+\end{verbatim}
-\membersection{wxStreamBuffer::wxStreamBuffer}
\func{}{wxStreamBuffer}{\param{BufMode}{ mode}}
-Constructor, creates a new empty stream buffer which won't flush any datas
-to a stream. \it{mode} specifies the type of the buffer (read,write,read_write).
+Constructor, creates a new empty stream buffer which won't flush any data
+to a stream. \it{mode} specifies the type of the buffer (read, write, read\_write). This stream buffer has the advantage to be stream independent and to
+work only on memory buffers but it is still compatible with the rest of the
+wxStream classes. You can write, read to this special stream and it will
+grow (if it is allowed by the user) its internal buffer. Briefly, it has all
+functionality of a ``normal'' stream.
+
+\wxheading{Warning}
+
+The "read\_write" mode may not work: it isn't completely finished.
+You can create "memory" streams by this way:
+
+\begin{verbatim}
+ wxStreamBuffer *sb = new wxStreamBuffer(wxStreamBuffer::read)
+ wxInputStream *input = new wxInputStream(sb);
-\membersection{wxStreamBuffer::wxStreamBuffer}
-\func{}{wxStreamBuffer}{\param{const wxStreamBase&}{ buffer}}
+ sb->Fixed(FALSE); // It can change the size of the buffer.
-Constructor, creates a new stream buffer from the specified stream \it{buffer}.
+ // input is now a read-only memory stream.
+\end{verbatim}
-\membersection{wxStreamBuffer::~wxStreamBuffer}
-\func{}{\destruct{wxStreamBuffer}}
+But you should take care when destroying the stream buffer yourself.
-Destructor, destroys the stream buffer.
+\func{}{wxStreamBuffer}{\param{const wxStreamBuffer\&}{buffer}}
+
+Constructor. It initializes the stream buffer with the data of the specified
+stream buffer. The new stream buffer is nearly exactly the same as the
+original: it has the same attributes, the same size, the same position, shares
+the same internal buffer. The interresting point is that they can differ
+in the future but the root is the same.
+
+\wxheading{Warning}
+
+The fact that the two stream buffers shared the same buffer could generate
+segmentation violation if the parent is destroyed and the children continues
+operating. It is advised to use this feature only in very local area of the
+program.
+
+\wxheading{See also}
+
+\helpref{wxStreamBuffer:SetBufferIO}{wxstreambuffersetbufferio}
+
+\membersection{wxStreamBuffer::\destruct{wxStreamBuffer}}
+
+\func{}{wxStreamBuffer}{\destruct{wxStreamBuffer}}
+
+Destructor. It finalizes all IO calls and frees all internal buffers if
+necessary. In the case of a children stream buffer, the internal buffer isn't
+freed, this is the job of the parent.
+The "Write-Back" buffer is freed.
% -----------
% Filtered IO
% -----------
+\membersection{wxStreamBuffer::Read}\label{wxstreambufferread}
-\membersection{wxStreamBuffer::Read}\label{wxstreambufread}
-\func{size_t}{Read}{\param{void *}{buffer}, \param{size_t }{size}}
+\func{size\_t}{Read}{\param{void *}{buffer}, \param{size\_t }{size}}
Reads a block of the specified \it{size} and stores datas in \it{buffer}.
+This function uses also the "Write-Back" buffer: in the case there are datas
+waiting in this buffer, they are used before anything else. After that, if there
+are still datas to be read, the stream is read and the stream buffer position
+is incremented.
\wxheading{Return value}
-It returns the real read size. If returned size is different of the specified
-\it{size}, an error occured and should be tested using
-\helpref{GetError}{wxstreambasegeterror}.
+It returns the real read size. If returned size is different of the specified
+\it{size}, an error occured and should be tested using
+\helpref{LastError}{wxstreambaselasterror}.
+
+\wxheading{See also}
+
+\helpref{wxStreamBuffer::WriteBack}{wxstreambufferwriteback}
-\membersection{wxStreamBuffer::Read}\label{wxstreambufreadbuf}
-\func{size_t}{Read}{\param{wxStreamBuffer *}{buffer}}
+\func{size\_t}{Read}{\param{wxStreamBuffer *}{buffer}}
Reads a \it{buffer}. The function returns when \it{buffer} is full or
when there aren't datas anymore in the current buffer.
-\membersection{wxStreamBuffer::Write}
-\func{size_t}{Write}{\param{const void *}{buffer}, \param{size_t }{size}}
+\membersection{wxStreamBuffer::Write}\label{wxstreambufferwrite}
+
+\func{size\_t}{Write}{\param{const void *}{buffer}, \param{size\_t }{size}}
-Writes a block of the specified \it{size} using datas of \it{buffer}.
+Writes a block of the specified \it{size} using datas of \it{buffer}. The datas
+are cached in a buffer before being sent in one block to the stream.
-\membersection{wxStreamBuffer::Write}
-\func{size_t}{Write}{\param{wxStreamBuffer *}{buffer}}
+\func{size\_t}{Write}{\param{wxStreamBuffer *}{buffer}}
-See \helpref{Read}{wxstreambufreadbuf}
+See \helpref{Read}{wxstreambufferread}.
-\membersection{wxStreamBuffer::WriteBack}
-\func{size_t}{WriteBack}{\param{const char *}{buffer}, \param{size_t}{ size}}
+\membersection{wxStreamBuffer::WriteBack}\label{wxstreambufferwriteback}
-This function is only useful in ``read'' mode. It puts the specified \it{buffer}
-in the input queue of the stream buf. By this way, the next
-\helpref{Read}{wxstreambufread} call will first use these datas.
+\func{size\_t}{WriteBack}{\param{const char*}{ buffer}, \param{size\_t}{ size}}
+
+This function is only useful in \it{read} mode. It is the manager of the "Write-Back"
+buffer. This buffer acts like a temporary buffer where datas which has to be
+read during the next read IO call are put. This is useful when you get a big
+block of data which you didn't want to read: you can replace them at the top
+of the input queue by this way.
+
+\wxheading{Return value}
-\membersection{wxStreamBuffer::WriteBack}
-\func{size_t}{WriteBack}{\param{char }{c}}
+Returns the amount of bytes saved in the Write-Back buffer.
-As for the previous function, it puts the specified byte in the input queue of the
-stream buffer.
+\func{size\_t}{WriteBack}{\param{char }{c}}
+
+This function acts like the previous one except that it takes only one
+character: it is sometimes shorter to use than the generic function.
\membersection{wxStreamBuffer::GetChar}
+
\func{char}{GetChar}{\void}
-Gets a single char from the stream buffer.
+Gets a single char from the stream buffer. It acts like the Read call.
+
+\wxheading{Problem}
+
+You aren't directly notified if an error occured during the IO call.
+
+\wxheading{See also}
+
+\helpref{wxStreamBuffer::Read}{wxstreambufferread}
\membersection{wxStreamBuffer::PutChar}
+
\func{void}{PutChar}{\param{char }{c}}
Puts a single char to the stream buffer.
+\wxheading{Problem}
+
+You aren't directly notified if an error occured during the IO call.
+
+\wxheading{See also}
+
+\helpref{wxStreamBuffer::Read}{wxstreambufferwrite}
+
\membersection{wxStreamBuffer::Tell}
-\constfunc{off_t}{Tell}{\void}
-Gets the current position in the \it{stream}.
+\constfunc{off\_t}{Tell}{\void}
-\membersection{wxStreamBuffer::Seek}
-\func{off_t}{Seek}{\param{off_t }{pos}, \param{wxSeekMode }{mode}}
+Gets the current position in the stream. This position is calculated from
+the \it{real} position in the stream and from the internal buffer position: so
+it gives you the position in the \it{real} stream counted from the start of
+the stream.
+
+\wxheading{Return value}
-Changes the current position. (TODO)
+Returns the current position in the stream if possible, wxInvalidOffset in the
+other case.
+
+\membersection{wxStreamBuffer::Seek}\label{wxstreambufferseek}
+
+\func{off\_t}{Seek}{\param{off\_t }{pos}, \param{wxSeekMode }{mode}}
+
+Changes the current position.
+
+\it{mode} may be one of the following:
+
+\twocolwidtha{5cm}
+\begin{twocollist}\itemsep=0pt
+\twocolitem{{\bf wxFromStart}}{The position is counted from the start of the stream.}
+\twocolitem{{\bf wxFromCurrent}}{The position is counted from the current position of the stream.}
+\twocolitem{{\bf wxFromEnd}}{The position is counted from the end of the stream.}
+\end{twocollist}
+
+\wxheading{Return value}
+
+Upon successful completion, it returns the new offset as measured in bytes from
+the beginning of the stream. Otherwise, it returns wxInvalidOffset.
% --------------
% Buffer control
% --------------
-
\membersection{wxStreamBuffer::ResetBuffer}
+
\func{void}{ResetBuffer}{\void}
-Frees all internal buffers and resets to initial state all variables.
+Resets to the initial state variables concerning the buffer.
-\membersection{wxStreamBuffer::SetBufferIO}
- \func{void}{SetBufferIO}{\param{char *}{ buffer_start}, \param{char *}{ buffer_end}}
+\membersection{wxStreamBuffer::SetBufferIO}\label{wxstreambuffersetbufferio}
+
+\func{void}{SetBufferIO}{\param{char*}{ buffer\_start}, \param{char*}{ buffer\_end}}
Specifies which pointers to use for stream buffering. You need to pass a pointer on the
-start of the buffer end and another on the end.
+start of the buffer end and another on the end. The object will use this buffer
+to cache stream data. It may be used also as a source/destination buffer when
+you create an empty stream buffer (See \helpref{wxStreamBuffer::wxStreamBuffer}{wxstreambufconst}).
+
+\wxheading{Remarks}
-\membersection{wxStreamBuffer::SetBufferIO}
-\func{void}{SetBufferIO}{\param{size_t}{ bufsize}}
+When you use this function, you'll have to destroy the IO buffers yourself
+after the stream buffer is destroyed or don't use it anymore.
+In the case you use it with an empty buffer, the stream buffer will not grow
+it when it is full.
-Changes the size of the current IO buffer.
+\wxheading{See also}
+
+\helpref{wxStreamBuffer constructor}{wxstreambufconst}\\
+\helpref{wxStreamBuffer::Fixed}{wxstreambufferfixed}\\
+\helpref{wxStreamBuffer::Flushable}{wxstreambufferflushable}
+
+\func{void}{SetBufferIO}{\param{size\_t}{ bufsize}}
+
+Destroys or invalidates the previous IO buffer and allocates a new one of the
+specified size.
+
+\wxheading{Warning}
+
+All previous pointers aren't valid anymore.
+
+\wxheading{Remark}
+
+The created IO buffer is growable by the object.
+
+\wxheading{See also}
+
+\helpref{wxStreamBuffer::Fixed}{wxstreambufferfixed}\\
+\helpref{wxStreamBuffer::Flushable}{wxstreambufferflushable}
\membersection{wxStreamBuffer::GetBufferStart}
+
\constfunc{char *}{GetBufferStart}{\void}
Returns a pointer on the start of the stream buffer.
\membersection{wxStreamBuffer::GetBufferEnd}
+
\constfunc{char *}{GetBufferEnd}{\void}
Returns a pointer on the end of the stream buffer.
\membersection{wxStreamBuffer::GetBufferPos}
+
\constfunc{char *}{GetBufferPos}{\void}
Returns a pointer on the current position of the stream buffer.
\membersection{wxStreamBuffer::GetIntPosition}
-\constfunc{off_t}{GetIntPosition}{\void}
-Returns the current position in the stream buffer.
+\constfunc{off\_t}{GetIntPosition}{\void}
+
+Returns the current position (counted in bytes) in the stream buffer.
\membersection{wxStreamBuffer::SetIntPosition}
+
\func{void}{SetIntPosition}{\void}
-Sets the current position in the stream buffer.
+Sets the current position (in bytes) in the stream buffer.
+
+\wxheading{Warning}
+
+Since it is a very low-level function, there is no check on the position:
+specify an invalid position can induce unexpected results.
\membersection{wxStreamBuffer::GetLastAccess}
-\constfunc{size_t}{GetLastAccess}{\void}
+
+\constfunc{size\_t}{GetLastAccess}{\void}
Returns the amount of bytes read during the last IO call to the parent stream.
-\membersection{wxStreamBuffer::Fixed}
+\membersection{wxStreamBuffer::Fixed}\label{wxstreambufferfixed}
+
\func{void}{Fixed}{\param{bool}{ fixed}}
-Toggles the fixed flag. Usually this flag is toggled at the same time that
-\it{flushable}. This flag allows (when it is false) or not (when it is true)
-the stream buffer to resize dynamically the IO buffer.
+Toggles the fixed flag. Usually this flag is toggled at the same time as
+\it{flushable}. This flag allows (when it has the FALSE value) or forbids
+(when it has the TRUE value) the stream buffer to resize dynamically the IO buffer.
+
+\wxheading{See also}
+
+\helpref{wxStreamBuffer::SetBufferIO}{wxstreambuffersetbufferio}
+
+\membersection{wxStreamBuffer::Flushable}\label{wxstreambufferflushable}
-\membersection{wxStreamBuffer::Flushable}
\func{void}{Flushable}{\param{bool}{ flushable}}
Toggles the flushable flag. If \it{flushable} is disabled, no datas are sent
to the parent stream.
\membersection{wxStreamBuffer::FlushBuffer}
+
\func{bool}{FlushBuffer}{\void}
Flushes the IO buffer.
\membersection{wxStreamBuffer::FillBuffer}
+
\func{bool}{FillBuffer}{\void}
Fill the IO buffer.
\membersection{wxStreamBuffer::GetDataLeft}
-\func{size_t}{GetDataLeft}{\void}
+
+\func{size\_t}{GetDataLeft}{\void}
Returns the amount of available datas in the buffer.
% --------------
% Administration
% --------------
-
\membersection{wxStreamBuffer::Stream}
-\func{wxStreamBase *}{Stream}{\void}
-Returns the stream parent of the stream buffer.
+\func{wxStreamBase*}{Stream}{\void}
+
+Returns the parent stream of the stream buffer.
+
projects / wxWidgets.git / blobdiff