    // Copyright (C) 2004  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #undef DLIB_MISC_API_KERNEl_ABSTRACT_
    #ifdef DLIB_MISC_API_KERNEl_ABSTRACT_

    #include <string>
    #include "../uintn.h"
    #include "../algs.h"

    namespace dlib
    {

    // ----------------------------------------------------------------------------------------

        /*!
            GENERAL COMMENTS
                This file just contains miscellaneous api functions
        !*/

    // ----------------------------------------------------------------------------------------

        void sleep (
            unsigned long milliseconds
        );
        /*!
            ensures
                - causes the calling thread to sleep for the given number of
                  milliseconds.
        !*/

    // ----------------------------------------------------------------------------------------

        std::string get_current_dir (
        );
        /*!
            ensures
                - if (no errors occur) then
                    - returns the path to the current working directory
                - else
                    - returns ""
            throws
                - std::bad_alloc
        !*/

    // ----------------------------------------------------------------------------------------

        class set_current_dir_error : public error;

        void set_current_dir (
            const std::string& new_dir
        );
        /*!
            ensures
                - sets the current working directory to new_dir
            throws
                - std::bad_alloc
                - set_current_dir_error
                  This exception is thrown if there is an error when attempting
                  to change the current working directory.
        !*/

    // ----------------------------------------------------------------------------------------

        class locally_change_current_dir : noncopyable
        {
            /*!
                WHAT THIS OBJECT REPRESENTS
                    This object is a RAII tool for safely switching the current directory
                    to a new directory and then automatically switching back to the original
                    directory upon this object's destruction.
            !*/
        public:
            explicit locally_change_current_dir (
                const std::string& new_dir
            );
            /*!
                ensures
                    - calls set_current_dir(new_dir)
                    - #old_dir() == The value of get_current_dir() prior to switching to new_dir.
            !*/

            const std::string& old_dir (
            ) const;
            /*!
                ensures
                    - returns the directory we switch back to once this object is destructed.
            !*/

            ~locally_change_current_dir(
            );
            /*!
                ensures
                    - if (revert() hasn't already been called) then
                        - calls set_current_dir(old_dir())
            !*/

            void revert (
            );
            /*!
                ensures
                    - if (revert() hasn't already been called) then
                        - calls set_current_dir(old_dir())
            !*/
        };

    // ----------------------------------------------------------------------------------------

        class dir_create_error : public error {
        public:
            const std::string name
        };

        void create_directory (
            const std::string& dir
        );
        /*!
            ensures
                - if (dir does not already exist) then
                    - creates the given directory.
                - else
                    - the call to create_directory() has no effect.
            throws
                - dir_create_error
                    This exception is thrown if we were unable to create the requested
                    directory and it didn't already exist.  The type member of the exception
                    will bet set to EDIR_CREATE and the name member will be set to dir.
        !*/

    // ----------------------------------------------------------------------------------------

        class timestamper
        {
            /*!
                WHAT THIS OBJECT REPRESENTS
                    This object represents a timer that is capable of returning
                    timestamps.

                    Note that the time is measured in microseconds but you are not
                    guaranteed to have that level of resolution.  The actual resolution
                    is implementation dependent.
            !*/

        public:
            uint64 get_timestamp (
            ) const;
            /*!
                ensures
                    - returns a timestamp that measures the time in microseconds since an
                      arbitrary point in the past.  Note that this arbitrary point remains
                      the same between all calls to get_timestamp().
            !*/
        };

    // ----------------------------------------------------------------------------------------

    }

    #endif // DLIB_MISC_API_KERNEl_ABSTRACT_