1 files changed, 69 insertions, 0 deletions
diff --git a/klm/util/tokenize_piece.hh b/klm/util/tokenize_piece.hh
new file mode 100644
index 00000000..ee1c7ab2
--- /dev/null
+++ b/klm/util/tokenize_piece.hh
@@ -0,0 +1,69 @@
+#ifndef UTIL_TOKENIZE_PIECE__
+#define UTIL_TOKENIZE_PIECE__
+
+#include "util/string_piece.hh"
+
+#include <boost/iterator/iterator_facade.hpp>
+
+/* Usage:
+ *
+ * for (PieceIterator<' '> i(" foo \r\n bar "); i; ++i) {
+ *   std::cout << *i << "\n";
+ * }
+ *
+ */
+
+namespace util {
+
+// Tokenize a StringPiece using an iterator interface.  boost::tokenizer doesn't work with StringPiece.
+template <char d> class PieceIterator : public boost::iterator_facade<PieceIterator<d>, const StringPiece, boost::forward_traversal_tag> {
+  public:
+    // Default construct is end, which is also accessed by kEndPieceIterator;
+    PieceIterator() {}
+
+    explicit PieceIterator(const StringPiece &str)
+      : after_(str) {
+        increment();
+      }
+
+    bool operator!() const {
+      return after_.data() == 0;
+    }
+    operator bool() const {
+      return after_.data() != 0;
+    }
+
+    static PieceIterator<d> end() {
+      return PieceIterator<d>();
+    }
+
+  private:
+    friend class boost::iterator_core_access;
+
+    void increment() {
+      const char *start = after_.data();
+      for (; (start != after_.data() + after_.size()) && (d == *start); ++start) {}
+      if (start == after_.data() + after_.size()) {
+        // End condition.
+        after_.clear();
+        return;
+      }
+      const char *finish = start;
+      for (; (finish != after_.data() + after_.size()) && (d != *finish); ++finish) {}
+      current_ = StringPiece(start, finish - start);
+      after_ = StringPiece(finish, after_.data() + after_.size() - finish);
+    }
+
+    bool equal(const PieceIterator &other) const {
+      return after_.data() == other.after_.data();
+    }
+
+    const StringPiece &dereference() const { return current_; }
+
+    StringPiece current_;
+    StringPiece after_;
+};
+
+} // namespace util
+
+#endif // UTIL_TOKENIZE_PIECE__