+ char c;
+ Read(&c, sizeof(c));
+ if (m_lasterror == wxSTREAM_NO_ERROR)
+ {
+ Ungetch(c);
+ return c;
+ }
+
+ return 0;
+}
+
+wxInputStream& wxInputStream::Read(wxOutputStream& stream_out)
+{
+ size_t lastcount = 0;
+ char buf[BUF_TEMP_SIZE];
+
+ for ( ;; )
+ {
+ size_t bytes_read = Read(buf, WXSIZEOF(buf)).LastRead();
+ if ( !bytes_read )
+ break;
+
+ if ( stream_out.Write(buf, bytes_read).LastWrite() != bytes_read )
+ break;
+
+ lastcount += bytes_read;
+ }
+
+ m_lastcount = lastcount;
+
+ return *this;
+}
+
+wxFileOffset wxInputStream::SeekI(wxFileOffset pos, wxSeekMode mode)
+{
+ // RR: This code is duplicated in wxBufferedInputStream. This is
+ // not really a good design, but buffered stream are different
+ // from all others in that they handle two stream-related objects:
+ // the stream buffer and parent stream.
+
+ // I don't know whether it should be put as well in wxFileInputStream::OnSysSeek
+ if (m_lasterror==wxSTREAM_EOF)
+ m_lasterror=wxSTREAM_NO_ERROR;
+
+ // avoid unnecessary seek operations (optimization)
+ wxFileOffset currentPos = TellI(), size = GetLength();
+ if ((mode == wxFromStart && currentPos == pos) ||
+ (mode == wxFromCurrent && pos == 0) ||
+ (mode == wxFromEnd && size != wxInvalidOffset && currentPos == size-pos))
+ return currentPos;
+
+ if (!IsSeekable() && mode == wxFromCurrent && pos > 0)
+ {
+ // rather than seeking, we can just read data and discard it;
+ // this allows to forward-seek also non-seekable streams!
+ char buf[BUF_TEMP_SIZE];
+ size_t bytes_read;
+
+ // read chunks of BUF_TEMP_SIZE bytes until we reach the new position
+ for ( ; pos >= BUF_TEMP_SIZE; pos -= bytes_read)
+ {
+ bytes_read = Read(buf, WXSIZEOF(buf)).LastRead();
+ if ( m_lasterror != wxSTREAM_NO_ERROR )
+ return wxInvalidOffset;
+
+ wxASSERT(bytes_read == WXSIZEOF(buf));
+ }
+
+ // read the last 'pos' bytes
+ bytes_read = Read(buf, (size_t)pos).LastRead();
+ if ( m_lasterror != wxSTREAM_NO_ERROR )
+ return wxInvalidOffset;
+
+ wxASSERT(bytes_read == (size_t)pos);
+
+ // we should now have sought to the right position...
+ return TellI();
+ }
+
+ /* RR: A call to SeekI() will automatically invalidate any previous
+ call to Ungetch(), otherwise it would be possible to SeekI() to
+ one position, unread some bytes there, SeekI() to another position
+ and the data would be corrupted.
+
+ GRG: Could add code here to try to navigate within the wback
+ buffer if possible, but is it really needed? It would only work
+ when seeking in wxFromCurrent mode, else it would invalidate
+ anyway... */
+
+ if (m_wback)
+ {
+ wxLogDebug( wxT("Seeking in stream which has data written back to it.") );
+
+ free(m_wback);
+ m_wback = NULL;
+ m_wbacksize = 0;
+ m_wbackcur = 0;
+ }
+
+ return OnSysSeek(pos, mode);
projects / wxWidgets.git / blobdiff