(svn r25652) -Fix: Improve text caret movement for complex scripts.

1 files changed, 60 insertions, 0 deletions

diff --git a/src/string_base.h b/src/string_base.h
new file mode 100644
index 000000000..73439f639
--- /dev/null
+++ b/src/string_base.h
@@ -0,0 +1,60 @@
+/* $Id$ */
+
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef STRING_BASE_H
+#define STRING_BASE_H
+
+#include "string_type.h"
+
+/** Class for iterating over different kind of parts of a string. */
+class StringIterator {
+public:
+	/** Sentinel to indicate end-of-iteration. */
+	static const size_t END = SIZE_MAX;
+
+	/**
+	 * Create a new iterator instance.
+	 * @return New iterator instance.
+	 */
+	static StringIterator *Create();
+
+	virtual ~StringIterator() {}
+
+	/**
+	 * Set a new iteration string. Must also be called if the string contents
+	 * changed. The cursor is reset to the start of the string.
+	 * @param s New string.
+	 */
+	virtual void SetString(const char *s) = 0;
+
+	/**
+	 * Change the current string cursor.
+	 * @param p New cursor position.
+	 * @return Actual new cursor position at the next valid character boundary.
+	 * @pre p has to be inside the current string.
+	 */
+	virtual size_t SetCurPosition(size_t pos) = 0;
+
+	/**
+	 * Advance the cursor by one iteration unit.
+	 * @return New cursor position (in bytes) or #END if the cursor is already at the end of the string.
+	 */
+	virtual size_t Next() = 0;
+
+	/**
+	 * Move the cursor back by one iteration unit.
+	 * @return New cursor position (in bytes) or #END if the cursor is already at the start of the string.
+	 */
+	virtual size_t Prev() = 0;
+
+protected:
+	StringIterator() {}
+};
+
+#endif /* STRING_BASE_H */