/*  Arg_parser - POSIX/GNU command line argument parser. (C++ version)
    Copyright (C) 2006-2018 Antonio Diaz Diaz.

    This library is free software. Redistribution and use in source and
    binary forms, with or without modification, are permitted provided
    that the following conditions are met:

    1. Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/

/*  Arg_parser reads the arguments in 'argv' and creates a number of
    option codes, option arguments and non-option arguments.

    In case of error, 'error' returns a non-empty error message.

    'options' is an array of 'struct Option' terminated by an element
    containing a code which is zero. A null name means a short-only
    option. A code value outside the unsigned char range means a
    long-only option.

    Arg_parser normally makes it appear as if all the option arguments
    were specified before all the non-option arguments for the purposes
    of parsing, even if the user of your program intermixed option and
    non-option arguments. If you want the arguments in the exact order
    the user typed them, call 'Arg_parser' with 'in_order' = true.

    The argument '--' terminates all options; any following arguments are
    treated as non-option arguments, even if they begin with a hyphen.

    The syntax for optional option arguments is '-<short_option><argument>'
    (without whitespace), or '--<long_option>=<argument>'.
*/

class Arg_parser
  {
public:
  enum Has_arg { no, yes, maybe };

  struct Option
    {
    int code;			// Short option letter or code ( code != 0 )
    const char * name;		// Long option name (maybe null)
    Has_arg has_arg;
    };

private:
  struct Record
    {
    int code;
    std::string argument;
    explicit Record( const int c ) : code( c ) {}
    explicit Record( const char * const arg ) : code( 0 ), argument( arg ) {}
    };

  std::string error_;
  std::vector< Record > data;

  bool parse_long_option( const char * const opt, const char * const arg,
                          const Option options[], int & argind );
  bool parse_short_option( const char * const opt, const char * const arg,
                           const Option options[], int & argind );

public:
  Arg_parser( const int argc, const char * const argv[],
              const Option options[], const bool in_order = false );

      // Restricted constructor. Parses a single token and argument (if any)
  Arg_parser( const char * const opt, const char * const arg,
              const Option options[] );

  const std::string & error() const { return error_; }

      // The number of arguments parsed (may be different from argc)
  int arguments() const { return data.size(); }

      // If code( i ) is 0, argument( i ) is a non-option.
      // Else argument( i ) is the option's argument (or empty).
  int code( const int i ) const
    {
    if( i >= 0 && i < arguments() ) return data[i].code;
    else return 0;
    }

  const std::string & argument( const int i ) const
    {
    if( i >= 0 && i < arguments() ) return data[i].argument;
    else return error_;
    }
  };
