document that CanRead() and GetImageCount() functions of wxImageHandlers do NOT modify the current stream position and that they require seekable streams; rename current GetImageCount() functions to DoGetImageCount() and put save-and-restore stream position logic in GetImageCount(); add comments in the various DoCanRead() and in DoGetImageCount() where the stream position is modified; remove unneeded SeekI(0) calls from DoCanRead() and DoGetImageCount() functions: they didn't allow to load images from non-seekable streams; implement forward-seeking in wxInputStream::SeekI() also for non-seekable streams

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@60852 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/xpmdecod.h

@@ -30,15 +30,20 @@ public:
 
 #if wxUSE_STREAMS
     // Is the stream XPM file?
+    // NOTE: this function modifies the current stream position
     bool CanRead(wxInputStream& stream);
+    
     // Read XPM file from the stream, parse it and create image from it
     wxImage ReadFile(wxInputStream& stream);
 #endif
+
     // Read directly from XPM data (as passed to wxBitmap ctor):
     wxImage ReadData(const char* const* xpm_data);
+    
 #ifdef __BORLANDC__
     // needed for Borland 5.5
-    wxImage ReadData(char** xpm_data) { return ReadData(const_cast<const char* const*>(xpm_data)); }
+    wxImage ReadData(char** xpm_data) 
+        { return ReadData(const_cast<const char* const*>(xpm_data)); }
 #endif
 };