+/** Create a digest for a file
+ * @param filename File name
+ * @param progress Optional progress reporting function. The function will be called
+ * with a progress value between 0 and 1
+ * @return Digest
+ */
+extern std::string make_digest (boost::filesystem::path filename, boost::function<void (float)>);
+
+extern std::string make_digest (ArrayData data);
+
+/** @param s A string
+ * @return true if the string contains only space, newline or tab characters, or is empty
+ */
+extern bool empty_or_white_space (std::string s);
+
+extern bool ids_equal (std::string a, std::string b);
+extern std::string remove_urn_uuid (std::string raw);
+
+/** Set up various bits that the library needs. Should be called once
+ * by client applications.
+ *
+ * @param tags_directory Path to a copy of the tags directory from the source code;
+ * if none is specified libdcp will look for a tags directory in the environment
+ * variable LIBDCP_RESOURCES or based on where the current executable is.
+ */
+extern void init (boost::optional<boost::filesystem::path> tags_directory = boost::optional<boost::filesystem::path>());
+
+/** Decode a base64 string. The base64 decode routine in KM_util.cpp
+ * gives different values to both this and the command-line base64
+ * for some inputs. Not sure why.
+ *
+ * @param in base64-encoded string
+ * @param out Output buffer
+ * @param out_length Length of output buffer
+ * @return Number of characters written to the output buffer
+ */
+extern int base64_decode (std::string const & in, unsigned char* out, int out_length);
+
+extern boost::optional<boost::filesystem::path> relative_to_root (boost::filesystem::path root, boost::filesystem::path file);
+
+/** @param p Path to open
+ * @param t mode flags, as for fopen(3)
+ * @return FILE pointer or 0 on error
+ *
+ * Apparently there is no way to create an ofstream using a UTF-8
+ * filename under Windows. We are hence reduced to using fopen
+ * with this wrapper.