Ensure that names of saved XPMs are valid C identifiers.

The name of the XPM should be based on the file name but can't always be
exactly equal to it as it's possible (and relatively common, e.g.
"foo-24.xpm") to have characters forbidden in identifiers to appear in the
file names. Ensure that we use a valid C identifier here.

Closes #13905.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72029 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/imagxpm.cpp

@@ -103,6 +103,45 @@ bool wxXPMHandler::LoadFile(wxImage *image,
     return true;
 }
 
+namespace
+{
+
+// Make the given string a valid C identifier.
+//
+// All invalid characters are simply replaced by underscores and underscore is
+// also prepended in the beginning if the initial character is not alphabetic.
+void
+MakeValidCIdent(wxString* str)
+{
+    const wxChar chUnderscore = wxT('_');
+
+    for ( wxString::iterator it = str->begin(); it != str->end(); ++it )
+    {
+        const wxChar ch = *it;
+        if ( wxIsdigit(ch) )
+        {
+            if ( it == str->begin() )
+            {
+                // Identifiers can't start with a digit.
+                str->insert(0, chUnderscore); // prepend underscore
+                it = str->begin(); // restart as string changed
+                continue;
+            }
+        }
+        else if ( !wxIsalpha(ch) && ch != chUnderscore )
+        {
+            // Not a valid character in C identifiers.
+            *it = chUnderscore;
+        }
+    }
+
+    // Double underscores are not allowed in normal C identifiers and are
+    // useless anyhow.
+    str->Replace(wxT("__"), wxT("_"));
+}
+
+} // anonymous namespace
+
 bool wxXPMHandler::SaveFile(wxImage * image,
                             wxOutputStream& stream, bool WXUNUSED(verbose))
 {
@@ -124,8 +163,8 @@ bool wxXPMHandler::SaveFile(wxImage * image,
     wxString sName;
     if ( image->HasOption(wxIMAGE_OPTION_FILENAME) )
     {
-        wxFileName::SplitPath(image->GetOption(wxIMAGE_OPTION_FILENAME),
-                              NULL, &sName, NULL);
+        sName = wxFileName(image->GetOption(wxIMAGE_OPTION_FILENAME)).GetName();
+        MakeValidCIdent(&sName);
         sName << wxT("_xpm");
     }