libbase/arg_parser.h

   1 //  Arg_parser - A POSIX/GNU command line argument parser.
   2 //    Copyright (C) 2006, 2007, 2008, 2009, 2010 Antonio Diaz Diaz.
   3 //    Copyright (C) 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   4 //
   5 //    This program is free software: you can redistribute it and/or modify
   6 //    it under the terms of the GNU General Public License as published by
   7 //    the Free Software Foundation, either version 3 of the License, or
   8 //    (at your option) any later version.
   9 //
  10 //    This program is distributed in the hope that it will be useful,
  11 //    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 //    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 //    GNU General Public License for more details.
  14 //
  15 //    You should have received a copy of the GNU General Public License
  16 //    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 //
  18 //
  19 //  Arg_parser reads the arguments in `argv' and creates a number of
  20 //    option codes, option arguments and non-option arguments.
  21 //
  22 //    In case of error, `error' returns a non-empty error message.
  23 //
  24 //    `options' is an array of `struct Option' terminated by an element
  25 //    containing a code which is zero. A null name means a short-only
  26 //    option. A code value outside the unsigned char range means a
  27 //    long-only option.
  28 //
  29 //    Arg_parser normally makes it appear as if all the option arguments
  30 //    were specified before all the non-option arguments for the purposes
  31 //    of parsing, even if the user of your program intermixed option and
  32 //    non-option arguments. If you want the arguments in the exact order
  33 //    the user typed them, call `Arg_parser' with `in_order' = true.
  34 //
  35 //    The argument `--' terminates all options; any following arguments are
  36 //    treated as non-option arguments, even if they begin with a hyphen.
  37 //
  38 //    The syntax for optional option arguments is `-<short_option><argument>'
  39 //    (without whitespace), or `--<long_option>=<argument>'.
  40
  41 // This class has been modified with a templated parser.argument<>
  42 // method, allowing typesafe handling of different return types, and
  43 // saving using strto* on the user side. I've added an exception class
  44 // because I'd like to know if we call an argument outside the range
  45 // of argument - there's no reasonable situation in which that would
  46 // happen. <bwy>
  47
  48 #include "dsodefs.h"
  49 #include <vector>
  50 #include <sstream>
  51
  52 class Arg_parser
  53 {
  54 public:
  55     enum Has_arg { no, yes, maybe };
  56
  57     struct Option
  58     {
  59         int code;                       // Short option letter or code ( code != 0 )
  60         const char * name;              // Long option name (maybe null)
  61         Has_arg has_arg;
  62     };
  63
  64     class ArgParserException : public std::exception
  65     {
  66     public:
  67         ArgParserException(const std::string& s)
  68             :
  69             _msg(s)
  70         {}
  71
  72         virtual ~ArgParserException() throw() {}
  73
  74         const char* what() const throw() { return _msg.c_str(); }
  75
  76     private:
  77
  78         std::string _msg;
  79     };
  80
  81 private:
  82     struct Record
  83     {
  84         int code;
  85         std::string argument;
  86         Record( const int c = 0 ) : code( c ) {}
  87     };
  88
  89     std::string _error;
  90     std::vector< Record > data;
  91
  92     bool parse_long_option( const char * const opt, const char * const arg,
  93                             const Option options[], int & argind ) throw();
  94     bool parse_short_option( const char * const opt, const char * const arg,
  95                              const Option options[], int & argind ) throw();
  96
  97 public:
  98     DSOEXPORT Arg_parser( const int argc, const char * const argv[],
  99                           const Option options[], const bool in_order = false ) throw();
 100
 101     // Restricted constructor. Parses a single token and argument (if any)
 102     DSOEXPORT Arg_parser( const char * const opt, const char * const arg,
 103                           const Option options[] ) throw();
 104
 105     const std::string & error() const throw() { return _error; }
 106
 107     // The number of arguments parsed (may be different from argc)
 108     int arguments() const throw() { return data.size(); }
 109
 110     // If code( i ) is 0, argument( i ) is a non-option.
 111     // Else argument( i ) is the option's argument (or empty).
 112     int code( const int i ) const throw()
 113     {
 114         if( i >= 0 && i < arguments() ) return data[i].code;
 115         else return 0;
 116     }
 117
 118     std::string argument(const int i) const throw(ArgParserException)
 119     {
 120         if( i >= 0 && i < arguments() ) return data[i].argument;
 121         else return _error;
 122     }
 123
 124     template<typename T>
 125     T argument(const int i) const throw (ArgParserException)
 126     {
 127         T t = 0;
 128         if( i >= 0 && i < arguments() )
 129             {
 130                 std::istringstream in(data[i].argument);
 131                 in >> t;
 132                 return t;
 133             }
 134         else throw ArgParserException("Code out of range");
 135     }
 136 };
 137
 138
 139 // local Variables:
 140 // mode: C++
 141 // indent-tabs-mode: t
 142 // End: