diff --git a/idlib/Str.cpp b/idlib/Str.cpp
index b37e1a9..4ccfb96 100644
--- a/idlib/Str.cpp
+++ b/idlib/Str.cpp
@@ -753,6 +753,26 @@ idStr &idStr::SetFileExtension( const char *extension ) {
 	return *this;
 }
 
+// DG: helper-function that returns true if the character c is a directory separator
+//     on the current platform
+static ID_INLINE bool isDirSeparator( int c )
+{
+	if ( c == '/' ) {
+		return true;
+	}
+#ifdef _WIN32
+	if ( c == '\\' ) {
+		return true;
+	}
+#elif defined(__AROS__)
+	if ( c == ':' ) {
+		return true;
+	}
+#endif
+	return false;
+}
+// DG end
+
 /*
 ============
 idStr::StripFileExtension
@@ -762,6 +782,10 @@ idStr &idStr::StripFileExtension( void ) {
 	int i;
 
 	for ( i = len-1; i >= 0; i-- ) {
+		// DG: we're at a directory separator, nothing to strip at filename
+		if ( isDirSeparator( data[i] ) ) {
+			break;
+		} // DG end
 		if ( data[i] == '.' ) {
 			data[i] = '\0';
 			len = i;
@@ -778,7 +802,9 @@ idStr::StripAbsoluteFileExtension
 */
 idStr &idStr::StripAbsoluteFileExtension( void ) {
 	int i;
-
+	// FIXME DG: seems like this is unused, but it probably doesn't do what's expected
+	//           (if you wanna strip .tar.gz this will fail with dots in path,
+	//            if you indeed wanna strip the first dot in *path* (even in some directory) this is right)
 	for ( i = 0; i < len; i++ ) {
 		if ( data[i] == '.' ) {
 			data[i] = '\0';
@@ -800,6 +826,10 @@ idStr &idStr::DefaultFileExtension( const char *extension ) {
 
 	// do nothing if the string already has an extension
 	for ( i = len-1; i >= 0; i-- ) {
+		// DG: we're at a directory separator, there was no file extension
+		if ( isDirSeparator( data[i] ) ) {
+			break;
+		} // DG end
 		if ( data[i] == '.' ) {
 			return *this;
 		}
@@ -817,11 +847,7 @@ idStr::DefaultPath
 ==================
 */
 idStr &idStr::DefaultPath( const char *basepath ) {
-#if defined(__AROS__)
-	if ( ( ( *this )[ 0 ] == '/' ) || ( ( *this )[ 0 ] == '\\' ) || ( ( *this )[ 0 ] == ':' ) ) {
-#else
-	if ( ( ( *this )[ 0 ] == '/' ) || ( ( *this )[ 0 ] == '\\' ) ) {
-#endif
+	if ( isDirSeparator( ( *this )[ 0 ] ) ) {
 		// absolute path location
 		return *this;
 	}
@@ -844,19 +870,12 @@ void idStr::AppendPath( const char *text ) {
 		EnsureAlloced( len + strlen( text ) + 2 );
 
 		if ( pos ) {
-#if defined(__AROS__)
-			if (( data[ pos-1 ] != '/' ) || ( data[ pos-1 ] != ':' )) {
-#else
-			if ( data[ pos-1 ] != '/' ) {
-#endif
+			if ( !isDirSeparator( data[ pos-1 ] ) ) {
 				data[ pos++ ] = '/';
 			}
 		}
-#if defined(__AROS__)
-		if (( text[i] == '/' ) || ( text[i] == ':' )) {
-#else
-		if ( text[i] == '/' ) {
-#endif
+
+		if ( isDirSeparator( text[ i ] ) ) {
 			i++;
 		}
 
@@ -881,11 +900,7 @@ idStr &idStr::StripFilename( void ) {
 	int pos;
 
 	pos = Length() - 1;
-#if defined(__AROS__)
-	while( ( pos > 0 ) && ( ( *this )[ pos ] != '/' ) && ( ( *this )[ pos ] != '\\' ) && ( ( *this )[ pos ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos ] != '/' ) && ( ( *this )[ pos ] != '\\' ) ) {
-#endif
+	while( ( pos > 0 ) && !isDirSeparator( ( *this )[ pos ] ) ) {
 		pos--;
 	}
 
@@ -906,11 +921,7 @@ idStr &idStr::StripPath( void ) {
 	int pos;
 
 	pos = Length();
-#if defined(__AROS__)
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' )  && ( ( *this )[ pos - 1 ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) ) {
-#endif
+	while( ( pos > 0 ) && !isDirSeparator( ( *this )[ pos - 1 ] ) ) {
 		pos--;
 	}
 
@@ -930,11 +941,7 @@ void idStr::ExtractFilePath( idStr &dest ) const {
 	// back up until a \ or the start
 	//
 	pos = Length();
-#if defined(__AROS__)
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) && ( ( *this )[ pos - 1 ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) ) {
-#endif
+	while( ( pos > 0 ) &&  !isDirSeparator( ( *this )[ pos - 1 ] ) ) {
 		pos--;
 	}
 
@@ -953,11 +960,7 @@ void idStr::ExtractFileName( idStr &dest ) const {
 	// back up until a \ or the start
 	//
 	pos = Length() - 1;
-#if defined(__AROS__)
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) && ( ( *this )[ pos - 1 ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) ) {
-#endif
+	while( ( pos > 0 ) && !isDirSeparator( ( *this )[ pos - 1 ] ) ) {
 		pos--;
 	}
 
@@ -977,11 +980,7 @@ void idStr::ExtractFileBase( idStr &dest ) const {
 	// back up until a \ or the start
 	//
 	pos = Length() - 1;
-#if defined(__AROS__)
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) && ( ( *this )[ pos - 1 ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) ) {
-#endif
+	while( ( pos > 0 ) && !isDirSeparator( ( *this )[ pos - 1 ] ) ) {
 		pos--;
 	}
 
@@ -1007,6 +1006,10 @@ void idStr::ExtractFileExtension( idStr &dest ) const {
 	pos = Length() - 1;
 	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '.' ) ) {
 		pos--;
+		if( isDirSeparator( ( *this )[ pos ] ) ) { // DG: check for directory separator
+			// no extension in the whole filename
+			dest.Empty();
+		} // DG end
 	}
 
 	if ( !pos ) {