Fix handling of paths with dots in dir names, fix #299, #301

idStr::StripFileExtension() (and SetFileExtension() which uses it) and
others didn't work correctly if there was a dot in a directory name,
because they just searched from last to first char for '.', so if the
current filename didn't have an extension to cut off, they'd just cut off
at any other '.' they found.
So D:\dev\doom3.data\base\maps\bla could turn into D:\dev\doom3
(or, for SetFileExtension(), D:\dev\doom3.map)

While at it, I made most of the idStr code that explicitly checked for '\\'
and '/' (and maybe ':' for AROS) use a little "bool isDirSeparator(int c)"
function so we don't have the #ifdefs for different platforms all over
the place.

neo/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 ( isDirSeparator( ( *this )[ 0 ] ) ) {
-	if ( ( ( *this )[ 0 ] == '/' ) || ( ( *this )[ 0 ] == '\\' ) || ( ( *this )[ 0 ] == ':' ) ) {
-#else
-	if ( ( ( *this )[ 0 ] == '/' ) || ( ( *this )[ 0 ] == '\\' ) ) {
-#endif
 		// 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 ( !isDirSeparator( data[ pos-1 ] ) ) {
-			if (( data[ pos-1 ] != '/' ) || ( data[ pos-1 ] != ':' )) {
-#else
-			if ( data[ pos-1 ] != '/' ) {
-#endif
 				data[ pos++ ] = '/';
 			}
 		}
-#if defined(__AROS__)
+
-		if (( text[i] == '/' ) || ( text[i] == ':' )) {
+		if ( isDirSeparator( text[ i ] ) ) {
-#else
-		if ( text[i] == '/' ) {
-#endif
 			i++;
 		}
 
@@ -881,11 +900,7 @@ idStr &idStr::StripFilename( void ) {
 	int pos;
 
 	pos = Length() - 1;
-#if defined(__AROS__)
+	while( ( pos > 0 ) && !isDirSeparator( ( *this )[ pos ] ) ) {
-	while( ( pos > 0 ) && ( ( *this )[ pos ] != '/' ) && ( ( *this )[ pos ] != '\\' ) && ( ( *this )[ pos ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos ] != '/' ) && ( ( *this )[ pos ] != '\\' ) ) {
-#endif
 		pos--;
 	}
 
@@ -906,11 +921,7 @@ idStr &idStr::StripPath( void ) {
 	int pos;
 
 	pos = Length();
-#if defined(__AROS__)
+	while( ( pos > 0 ) && !isDirSeparator( ( *this )[ pos - 1 ] ) ) {
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' )  && ( ( *this )[ pos - 1 ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) ) {
-#endif
 		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 ) &&  !isDirSeparator( ( *this )[ pos - 1 ] ) ) {
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) && ( ( *this )[ pos - 1 ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) ) {
-#endif
 		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 ) && !isDirSeparator( ( *this )[ pos - 1 ] ) ) {
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) && ( ( *this )[ pos - 1 ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) ) {
-#endif
 		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 ) && !isDirSeparator( ( *this )[ pos - 1 ] ) ) {
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) && ( ( *this )[ pos - 1 ] != ':' ) ) {
-#else
-	while( ( pos > 0 ) && ( ( *this )[ pos - 1 ] != '/' ) && ( ( *this )[ pos - 1 ] != '\\' ) ) {
-#endif
 		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 ) {