// ****************************************************************************
// ^FILE: options.h - option parsing classes
//
// ^DESCRIPTION:
//    This file defines classes used to parse command-line options.
//    Options may be parsed from an array of strings, or from any structure
//    for which a corresponding option-iterator exists.
//
// ^HISTORY:
//    03/06/92  Brad Appleton   <bradapp@enteract.com>   Created
//
//    03/23/93	Brad Appleton	<bradapp@enteract.com>
//    - Added OptIstreamIter class
//
//    03/08/94	Brad Appleton	<bradapp@enteract.com>
//    - Added Options::reset() member function
//
//    07/31/97	Brad Appleton	<bradapp@enteract.com>
//    - Added PARSE_POS control flag and POSITIONAL return value
//
//	  04/30/06  Chris Reed
//    - Updated to modern C++ and STL
//    - Converted comments to doxygen style
// ^^**************************************************************************

#ifndef _options_h
#define _options_h

#ifdef USE_STDIO
	#include <stdio.h>
#else
	#include <iostream>
#endif


//! Abstract class to iterate through options/arguments
//!
class OptIter {
public:
   OptIter(void) {}
   virtual ~OptIter(void);

      //! curr() returns the current item in the iterator without
      //! advancing on to the next item. If we are at the end of items
      //! then NULL is returned.
   virtual const char *
   curr(void) = 0;

      //! next() advances to the next item.
   virtual void
   next(void) = 0;

      //! operator() returns the current item in the iterator and then
      //! advances on to the next item. If we are at the end of items
      //! then NULL is returned.
   virtual const char *
   operator()(void);
} ;

//! Abstract class for a rewindable OptIter
//!
class OptIterRwd : public OptIter {
public:
   OptIterRwd(void);

   virtual ~OptIterRwd(void);

   virtual const char *
   curr(void) = 0;

   virtual void
   next(void) = 0;

   virtual const char *
   operator()(void) = 0;

      //! rewind() resets the "current-element" to the first one in the "list"
   virtual void
   rewind(void) = 0;
} ;

//! Class to iterate through an array of tokens. The array may be terminated
//! by NULL or a count containing the number of tokens may be given.
//!
class OptArgvIter : public OptIterRwd {
private:
   int            ndx;   // index of current arg
   int            ac;    // arg count
   const char * const * av;  // arg vector

public:
   OptArgvIter(const char * const argv[])
      : ndx(0), ac(-1), av(argv) {}

   OptArgvIter(int argc, const char * const argv[])
      : ndx(0), ac(argc), av(argv) {}

   virtual
   ~OptArgvIter(void);

   virtual const char *
   curr(void);

   virtual void
   next(void);

   virtual const char *
   operator()(void);

   virtual void
   rewind(void);

      //! index returns the current index to use for argv[]
   int index(void)  { return  ndx; }
} ;


//! Class to iterate through a string containing delimiter-separated tokens
//!
class OptStrTokIter : public OptIterRwd {
private:
   unsigned     len;        // length of token-string
   const char * str;        // the token-string
   const char * seps;       // delimiter-set (separator-characters)
   const char * cur;        // current token
   char       * tokstr;     // our copy of the token-string

   static const char * default_delims;  // default delimiters = whitespace

public:
   OptStrTokIter(const char * tokens, const char * delimiters =0);

   virtual
   ~OptStrTokIter(void);

   virtual const char *
   curr(void);

   virtual void
   next(void);

   virtual const char *
   operator()(void);

   virtual void
   rewind(void);

      //! delimiters() with NO arguments returns the current set of delimiters,
      //! If an argument is given then it is used as the new set of delimiters.
   const char *
   delimiters(void)  { return  seps; }

   void
   delimiters(const char * delims) {
      seps = (delims) ? delims : default_delims ;
   }
} ;


//! OptIstreamIter is a class for iterating over arguments that come
//! from an input stream. Each line of the input stream is considered
//! to be a set of white-space separated tokens. If the the first
//! non-white character on a line is '#' ('!' for VMS systems) then
//! the line is considered a comment and is ignored.
//!
//! \note If a line is more than 1022 characters in length then we
//! treat it as if it were several lines of length 1022 or less.
//!
//! \note The string tokens returned by this iterator are pointers
//!         to temporary buffers which may not necessarily stick around
//!         for too long after the call to curr() or operator(), hence
//!         if you need the string value to persist - you will need to
//!         make a copy.
//!
class OptIstreamIter : public OptIter {
private:
   std::istream & is ;
   OptStrTokIter * tok_iter ;

   void
   fill(void);

public:
   static const unsigned  MAX_LINE_LEN ;

   OptIstreamIter(std::istream & input);

   virtual
   ~OptIstreamIter(void);

   virtual const char *
   curr(void);

   virtual void
   next(void);

   virtual const char *
   operator()(void);
} ;


//! \brief parse command-line options
//!
//! \section Synopsis
//! \code
//!   #include <options.h>
//!
//!   Options opts(cmdname, optv);
//!   char cmdname[], *optv[];
//! \endcode
//! \section Description
//! The Options constructor expects a command-name (usually argv[0]) and
//! a pointer to an array of strings.  The last element in this array MUST
//! be NULL. Each non-NULL string in the array must have the following format:
//!
//!   The 1st character must be the option-name ('c' for a -c option).
//!
//!   The 2nd character must be one of '|', '?', ':', '*', or '+'.
//!      '|' -- indicates that the option takes NO argument;
//!      '?' -- indicates that the option takes an OPTIONAL argument;
//!      ':' -- indicates that the option takes a REQUIRED argument;
//!      '*' -- indicates that the option takes 0 or more arguments;
//!      '+' -- indicates that the option takes 1 or more arguments;
//!
//!   The remainder of the string must be the long-option name.
//!
//!   If desired, the long-option name may be followed by one or more
//!   spaces and then by the name of the option value. This name will
//!   be used when printing usage messages. If the option-value-name
//!   is not given then the string "<value>" will be used in usage
//!   messages.
//!
//!   One may use a space to indicate that a particular option does not
//!   have a corresponding long-option.  For example, "c: " (or "c:")
//!   means the -c option takes a value & has NO corresponding long-option.
//!
//!   To specify a long-option that has no corresponding single-character
//!   option is a bit trickier: Options::operator() still needs an "option-
//!   character" to return when that option is matched. One may use a whitespace
//!   character or a non-printable character as the single-character option
//!   in such a case. (hence " |hello" would only match "--hello").
//!
//!   \section Exceptions Exceptions to the above
//!   If the 1st character of the string is '-', then the rest of the
//!   string must correspond to the above format, and the option is
//!   considered to be a hidden-option. This means it will be parsed
//!   when actually matching options from the command-line, but will
//!   NOT show-up if a usage message is printed using the usage() member
//!   function. Such an example might be "-h|hidden". If you want to
//!   use any "dummy" options (options that are not parsed, but that
//!   to show up in the usage message), you can specify them along with
//!   any positional parameters to the usage() member function.
//!
//!   If the 2nd character of the string is '\0' then it is assumed
//!   that there is no corresponding long-option and that the option
//!   takes no argument (hence "f", and "f| " are equivalent).
//!
//!   \code
//!      const char * optv[] = {
//!          "c:count   <number>",
//!          "s?str     <string>",
//!          "x",
//!          " |hello",
//!          "g+groups  <newsgroup>",
//!          NULL
//!      } ;
//!    \endcode
//!      optv[] now corresponds to the following:
//!
//!            usage: cmdname [-c|--count <number>] [-s|--str [<string>]]
//!                           [-x] [--hello] [-g|--groups <newsgroup> ...]
//!
//! Long-option names are matched case-insensitive and only a unique prefix
//! of the name needs to be specified.
//!
//! Option-name characters are case-sensitive!
//!
//! \section Caveat
//! Because of the way in which multi-valued options and options with optional
//! values are handled, it is NOT possible to supply a value to an option in
//! a separate argument (different argv[] element) if the value is OPTIONAL
//! and begins with a '-'. What this means is that if an option "-s" takes an
//! optional value value and you wish to supply a value of "-foo" then you must
//! specify this on the command-line as "-s-foo" instead of "-s -foo" because
//! "-s -foo" will be considered to be two separate sets of options.
//!
//! A multi-valued option is terminated by another option or by the end-of
//! options. The following are all equivalent (if "-l" is a multi-valued
//! option and "-x" is an option that takes no value):
//!
//!    cmdname -x -l item1 item2 item3 -- arg1 arg2 arg3
//!    cmdname -x -litem1 -litem2 -litem3 -- arg1 arg2 arg3
//!    cmdname -l item1 item2 item3 -x arg1 arg2 arg3
//!
//!
//! \code
//!    #include <options.h>
//!
//!    static const char * optv[] = {
//!       "H|help",
//!       "c:count   <number>",
//!       "s?str     <string>",
//!       "x",
//!       " |hello",
//!       "g+groups  <newsgroup>",
//!       NULL
//!    } ;
//!
//!    main(int argc, char * argv[]) {
//!       int  optchar;
//!       const char * optarg;
//!       const char * str = "default_string";
//!       int  count = 0, xflag = 0, hello = 0;
//!       int  errors = 0, ngroups = 0;
//!    
//!       Options  opts(*argv, optv);
//!       OptArgvIter  iter(--argc, ++argv);
//!    
//!       while( optchar = opts(iter, optarg) ) {
//!          switch (optchar) {
//!          case 'H' :
//!             opts.usage(cout, "files ...");
//!             exit(0);
//!             break;
//!          case 'g' :
//!             ++ngroups; break;  //! the groupname is in "optarg"
//!          case 's' :
//!             str = optarg; break;
//!          case 'x' :
//!             ++xflag; break;
//!          case ' ' :
//!             ++hello; break;
//!          case 'c' :
//!             if (optarg == NULL)  ++errors;
//!             else  count = (int) atol(optarg);
//!             break;
//!          default :  ++errors; break;
//!          } //!switch
//!       }
//!    
//!       if (errors || (iter.index() == argc)) {
//!          if (! errors) {
//!             cerr << opts.name() << ": no filenames given." << endl ;
//!          }
//!          opts.usage(cerr, "files ...");
//!          exit(1);
//!       }
//!    
//!       cout << "xflag=" << ((xflag) ? "ON"  : "OFF") << endl
//!            << "hello=" << ((hello) ? "YES" : "NO") << endl
//!            << "count=" << count << endl
//!            << "str=\"" << ((str) ? str : "No value given!") << "\"" << endl
//!            << "ngroups=" << ngroups << endl ;
//!    
//!       if (iter.index() < argc) {
//!          cout << "files=" ;
//!          for (int i = iter.index() ; i < argc ; i++) {
//!             cout << "\"" << argv[i] << "\" " ;
//!          }
//!          cout << endl ;
//!       }
//!    }
//! \endcode
class Options {
private:
   unsigned       explicit_end : 1;  //!< were we terminated because of "--"?
   unsigned       optctrls : 7;  //!< control settings (a set of OptCtrl masks)
   const char  * const * optvec; //!< vector of option-specifications (last=NULL)
   const char   * nextchar;      //!< next option-character to process
   const char   * listopt;       //!< last list-option we matched
   const char   * cmdname;       //!< name of the command

   void
   check_syntax(void) const;

   const char *
   match_opt(char opt, int ignore_case =0) const;

   const char *
   match_longopt(const char * opt, int  len, int & ambiguous) const;

   int
   parse_opt(OptIter & iter, const char * & optarg);

   int
   parse_longopt(OptIter & iter, const char * & optarg);

public:
   enum OptCtrl {
      DEFAULT    = 0x00,  //!< Default setting
      ANYCASE    = 0x01,  //!< Ignore case when matching short-options
      QUIET      = 0x02,  //!< Dont print error messages
      PLUS       = 0x04,  //!< Allow "+" as a long-option prefix
      SHORT_ONLY = 0x08,  //!< Dont accept long-options
      LONG_ONLY  = 0x10,  //!< Dont accept short-options
                            //!< (also allows "-" as a long-option prefix).
      NOGUESSING = 0x20,  //!< Normally, when we see a short (long) option
                            //!< on the command line that doesnt match any
                            //!< known short (long) options, then we try to
                            //!< "guess" by seeing if it will match any known
                            //!< long (short) option. Setting this mask prevents
                            //!< this "guessing" from occurring.
      PARSE_POS = 0x40    //!< By default, Options will not present positional
                            //!< command-line arguments to the user and will
                            //!< instead stop parsing when the first positonal
                            //!< argument has been encountered. If this flag
                            //!< is given, Options will present positional
                            //!< arguments to the user with a return code of
                            //!< POSITIONAL; ENDOPTS will be returned only
                            //!< when the end of the argument list is reached.
   } ;

      //! Error return values for operator()
      //!
   enum OptRC {
      ENDOPTS    =  0,
      BADCHAR    = -1,
      BADKWD     = -2,
      AMBIGUOUS  = -3,
      POSITIONAL = -4
   } ;

   Options(const char * name, const char * const optv[]);

   virtual
   ~Options(void);

      //! name() returns the command name
   const char *
   name(void) const { return  cmdname; }

      //! ctrls() (with no arguments) returns the existing control settings
   unsigned
   ctrls(void) const { return  optctrls; }

      //! ctrls() (with 1 argument) sets new control settings
   void
   ctrls(unsigned newctrls) { optctrls = newctrls; }

      //! reset for another pass to parse for options
   void
   reset(void) { nextchar = listopt = NULL; }
  
      //! usage() prints options usage (followed by any positional arguments
      //! listed in the parameter "positionals") on the given outstream
   void
   usage(std::ostream & os, const char * positionals) const ;

      //! operator() iterates through the arguments as necessary (using the
      //! given iterator) and returns the character value of the option
      //! (or long-option) that it matched. If the option has a value
      //! then the value given may be found in optarg (otherwise optarg
      //! will be NULL).
      //!
      //! 0 is returned upon end-of-options. At this point, "iter" may
      //! be used to process any remaining positional parameters. If the
      //! PARSE_POS control-flag is set then 0 is returned only when all
      //! arguments in "iter" have been exhausted.
      //!
      //! If an invalid option is found then BADCHAR is returned and *optarg
      //! is the unrecognized option character.
      //!
      //! If an invalid long-option is found then BADKWD is returned and optarg
      //! points to the bad long-option.
      //!
      //! If an ambiguous long-option is found then AMBIGUOUS is returned and
      //! optarg points to the ambiguous long-option.
      //!
      //! If the PARSE_POS control-flag is set then POSITIONAL is returned
      //! when a positional argument is encountered and optarg points to
      //! the positonal argument (and "iter" is advanced to the next argument
      //! in the iterator).
      //!
      //! Unless Options::QUIET is used, missing option-arguments and
      //! invalid options (and the like) will automatically cause error
      //! messages to be issued to cerr.
   int
   operator()(OptIter & iter, const char * & optarg) ;

      //! Call this member function after operator() has returned 0
      //! if you want to know whether or not options were explicitly
      //! terminated because "--" appeared on the command-line.
      //!
   int
   explicit_endopts() const { return  explicit_end; }
} ;

#endif /* _options_h */