1 files changed, 39 insertions, 0 deletions
diff --git a/include/cru/common/StringUtil.hpp b/include/cru/common/StringUtil.hpp
new file mode 100644
index 00000000..a44ae6b4
--- /dev/null
+++ b/include/cru/common/StringUtil.hpp
@@ -0,0 +1,39 @@
+#pragma once
+#include "Base.hpp"
+
+namespace cru {
+using CodePoint = std::int32_t;
+constexpr CodePoint k_code_point_end = -1;
+
+class TextEncodeException : public std::runtime_error {
+ public:
+  using runtime_error::runtime_error;
+};
+
+class Utf8Iterator : public Object {
+ public:
+  explicit Utf8Iterator(const std::string_view& string) : string_(string) {}
+  Utf8Iterator(const std::string_view& string, Index position)
+      : string_(string), position_(position) {}
+
+  CRU_DEFAULT_COPY(Utf8Iterator)
+  CRU_DEFAULT_MOVE(Utf8Iterator)
+
+  ~Utf8Iterator() = default;
+
+ public:
+  void SetToHead() { position_ = 0; }
+  void SetPosition(Index position) { position_ = position; }
+
+  // Advance current position and get next code point. Return k_code_point_end
+  // if there is no next code unit(point). Throw TextEncodeException if decoding
+  // fails.
+  CodePoint Next();
+
+  Index CurrentPosition() const { return this->position_; }
+
+ private:
+  std::string_view string_;
+  Index position_ = 0;
+};
+}  // namespace cru