1 files changed, 43 insertions, 0 deletions
diff --git a/klm/util/string_piece_hash.hh b/klm/util/string_piece_hash.hh
new file mode 100644
index 00000000..f206b1d8
--- /dev/null
+++ b/klm/util/string_piece_hash.hh
@@ -0,0 +1,43 @@
+#ifndef UTIL_STRING_PIECE_HASH__
+#define UTIL_STRING_PIECE_HASH__
+
+#include "util/string_piece.hh"
+
+#include <boost/functional/hash.hpp>
+#include <boost/version.hpp>
+
+inline size_t hash_value(const StringPiece &str) {
+  return boost::hash_range(str.data(), str.data() + str.length());
+}
+
+/* Support for lookup of StringPiece in boost::unordered_map<std::string> */
+struct StringPieceCompatibleHash : public std::unary_function<const StringPiece &, size_t> {
+  size_t operator()(const StringPiece &str) const {
+    return hash_value(str);
+  }
+};
+
+struct StringPieceCompatibleEquals : public std::binary_function<const StringPiece &, const std::string &, bool> {
+  bool operator()(const StringPiece &first, const StringPiece &second) const {
+    return first == second;
+  }
+};
+template <class T> typename T::const_iterator FindStringPiece(const T &t, const StringPiece &key) {
+#if BOOST_VERSION < 104200
+  std::string temp(key.data(), key.size());
+  return t.find(temp);
+#else
+  return t.find(key, StringPieceCompatibleHash(), StringPieceCompatibleEquals());
+#endif
+}
+
+template <class T> typename T::iterator FindStringPiece(T &t, const StringPiece &key) {
+#if BOOST_VERSION < 104200
+  std::string temp(key.data(), key.size());
+  return t.find(temp);
+#else
+  return t.find(key, StringPieceCompatibleHash(), StringPieceCompatibleEquals());
+#endif
+}
+
+#endif // UTIL_STRING_PIECE_HASH__