/* -*- C++ -*- */
// $Id$

// ============================================================================
//
// = LIBRARY
//    ace
// 
// = FILENAME
//    Get_Opt.h
//
// = AUTHOR
//    Doug Schmidt 
// 
// ============================================================================

#if !defined (ACE_GET_OPT_H)
#define ACE_GET_OPT_H

#include "ace/ACE.h"

class ACE_Export ACE_Get_Opt
  // = TITLE
  //   Iterator for parsing command-line arguments.
  //
  // = DESCRIPTION
  //    This is a C++ wrapper for getopt(3c).
{
public:
  ACE_Get_Opt (int argc, 
	       char **argv, 
	       char *optstring, 
	       int skip_argv0 = 1, 
	       int report_errors = 0);
  // Initialize the internal data when the first call is made.  Start
  // processing options with <argv>-element 0 + <skip_argv0>; the
  // sequence of previously skipped non-option <argv>-elements is
  // empty.
  // 
  // <optstring> is a string containing the legitimate option
  // characters.  A colon in <optstring> means that the previous
  // character is an option that wants an argument.  The argument is
  // taken from the rest of the current <argv>-element, or from the
  // following <argv>-element, and returned in <optarg>.
  // 
  // If an option character is seen that is not listed in <optstring>,
  // return '?' after printing an error message.  If you set <opterr>
  // to zero, the error message is suppressed but we still return '?'.
  // 
  // If a char in <optstring> is followed by a colon, that means it
  // wants an arg, so the following text in the same <argv>-element,
  // or the text of the following <argv>-element, is returned in
  // <optarg>.

  int operator () (void);
  // Scan elements of <argv> (whose length is <argc>) for option
  // characters given in <optstring>.
  //
  // If an element of <argv> starts with '-', and is not exactly "-"
  // or "--", then it is an option element.  The characters of this
  // element (aside from the initial '-') are option characters.  If
  // <operator()> is called repeatedly, it returns successively each
  // of the option characters from each of the option elements.
  // 
  // If <operator()> finds another option character, it returns that
  // character, updating <optind> and <nextchar> so that the next call
  // to <operator()> can resume the scan with the following option
  // character or <argv>-element.
  // 
  // If there are no more option characters, <operator()> returns
  // <EOF>.  Then <optind> is the index in <argv> of the first
  // <argv>-element that is not an option.  (The <argv>-elements have
  // been permuted so that those that are not options now come last.)

  // = Public data members (should be hidden...).

  char *optarg;
  // For communication from <operator()> to the caller.  When
  // <operator()> finds an option that takes an argument, the argument
  // value is returned here.
  
  int optind;
  // Index in <argv> of the next element to be scanned.  This is used
  // for communication to and from the caller and for communication
  // between successive calls to <operator()>.  On entry to
  // <operator()>, zero means this is the first call; initialize.
  //      
  // When <get_opt> returns <EOF>, this is the index of the first of
  // the non-option elements that the caller should itself scan.
  //          
  // Otherwise, <optind> communicates from one call to the next how
  // much of <argv> has been scanned so far.

  int opterr;
  // Callers store zero here to inhibit the error message for
  // unrecognized options.
  
  int argc_;
  // Holds the <argc> count.

  char **argv_;
  // Holds the <argv> pointer.  

  void dump (void) const;
  // Dump the state of an object.

  ACE_ALLOC_HOOK_DECLARE;
  // Declare the dynamic allocation hooks.

private:
  
  char *nextchar_;
  // The next char to be scanned in the option-element in which the
  // last option character we returned was found.  This allows us to
  // pick up the scan where we left off.
  //    
  // If this is zero, or a null string, it means resume the scan
  // by advancing to the next <argv>-element.

  char *optstring_;
  // Holds the option string.
};

#if defined (__ACE_INLINE__)
#include "ace/Get_Opt.i"
#endif /* __ACE_INLINE__ */

#endif /* ACE_GET_OPT_H */