-- General Utility Package

    PACKAGE utils IS

--    Package Functions :

--    ch_is_upper => Is character an upper case letter ?
       FUNCTION ch_is_upper ( c : CHARACTER ) RETURN BOOLEAN ;

--    ch_is_lower => Is character a lower case letter ?
       FUNCTION ch_is_lower ( c : CHARACTER ) RETURN BOOLEAN ;

--    upper_case => Return upper case equivalent of a character.
       FUNCTION upper_case ( c : CHARACTER ) RETURN CHARACTER ;

--    lower_case => Return lower case equivalent of a character.
       FUNCTION lower_case ( c : CHARACTER ) RETURN CHARACTER ;

--    upper_case => Return upper case equivalent of a string.
       FUNCTION upper_case ( s : STRING ) RETURN STRING ;

--    lower_case => Return lower case equivalent of a string.
       FUNCTION lower_case ( s : STRING ) RETURN STRING ;

    END utils ; --------------------------------------------------------

    PACKAGE BODY utils IS

--    ch_is_upper => Is given character an upper case letter ?
       FUNCTION ch_is_upper ( c : CHARACTER ) RETURN BOOLEAN IS

       BEGIN -- ch_is_upper

--    simply check character lies between 'A' and 'Z'
       RETURN ( ( c >= 'A' ) AND ( c <= 'Z' ) ) ;

       END ch_is_upper ; -----------------------------------------------

--    ch_is_lower => Is given character a lower case letter ?
       FUNCTION ch_is_lower ( c : CHARACTER ) RETURN BOOLEAN IS

       BEGIN -- ch_is_lower

--    simply check character lies between 'a' and 'z'
       RETURN ( ( c >= 'a' ) AND ( c <= 'z' ) ) ;

       END ch_is_lower ; -----------------------------------------------

--    upper_case => Convert character from lower to upper case.
       FUNCTION upper_case ( c : CHARACTER ) RETURN CHARACTER IS

--    Local Constants :

--    offset between lower and upper case character sets
       offset : CONSTANT INTEGER := -32 ;

       BEGIN -- upper_case

--    check character is lower case letter & convert it if it is
       IF ch_is_lower ( c ) THEN
          RETURN CHARACTER'VAL ( CHARACTER'POS ( c ) + offset ) ;
       ELSE
          RETURN c ;
       END IF ;

       END upper_case ; ------------------------------------------------

--    lower_case => Convert character from upper to lower case.
       FUNCTION lower_case ( c : CHARACTER ) RETURN CHARACTER IS

--    Local Constants :

--    offset between upper and lower case characters
       offset : CONSTANT INTEGER := 32 ;

       BEGIN -- lower_case

--    check character is upper case letter & convert it if it is
       IF ch_is_upper ( c ) THEN
          RETURN CHARACTER'VAL ( CHARACTER'POS ( c ) + offset ) ;
       ELSE
          RETURN c ;
       END IF ;

       END lower_case ; ------------------------------------------------

--    upper_case => Convert string from lower to upper case.
       FUNCTION upper_case ( s : STRING ) RETURN STRING IS

--    Local Variables :

       u : STRING ( 1..s'LENGTH ) ; -- local storage for result

       BEGIN -- upper_case

--    loop through input string converting characters
       FOR ch IN 1..s'LENGTH LOOP
          u ( ch ) := upper_case ( s ( ch ) ) ;
       END LOOP ;

--    return result
       RETURN u ;

       END upper_case ; ------------------------------------------------

--    lower_case => Convert string from upper to lower case.
       FUNCTION lower_case ( s : STRING ) RETURN STRING IS

--    Local Variables :

       l : STRING ( 1..s'LENGTH ) ;

       BEGIN -- lower_case

--    loop through given string converting characters
       FOR ch IN 1..s'LENGTH LOOP
          l ( ch ) := lower_case ( s ( ch ) ) ;
       END LOOP ;

--    return result
       RETURN l ;

       END lower_case ; ------------------------------------------------

    END utils ; --------------------------------------------------------