options.h

// $Id$
#if !defined(OPTIONS_H)
#define OPTIONS_H

#include <stdexcept>
#include <string>
#include <vector>

#define POSIX_SOURCE 1

namespace Utilities {

  bool string_to_T(bool &b, const string& s); 
  bool string_to_T(string& d, const string& s); 
  bool string_to_T(int& i, const string& s); 
  bool string_to_T(float& v, const string& s); 
  bool string_to_T(vector<int>& vi, const string& s);
  bool string_to_T(vector<float>& vi, const string& s);
 
  typedef enum argflag { 
    no_argument = 0, requires_argument, optional_argument 
  } ArgFlag;

}

namespace Utilities {

  /**
     Provides behaviour common to all option types. Actual options are
     declared using the templated Option class. The 
     OptionParser class can be used to parse command lines.
     @see Option
     @see OptionParser
     @author Dave Flitney
     @version 1.0b, Nov., 2000.
  */
  class BaseOption {
  public:
    /**
       @param k comma seperated list of key aliases
       @param ht the help text to be printed for this option
       @param c if true then this option is compulsory
       @param f one of no_argument, requires_argument, optional_argument
       to indicate what arguments should be supplied
    */
    BaseOption(const string& k, const string& ht, bool c, ArgFlag f): 
      key_(k), help_text_(ht), arg_flag_(f), 
      unset_(true), compulsory_(c), visible_(true) {}
    /**
       @param k comma seperated list of key aliases
       @param ht the help text to be printed for this option
       @param c if true then this option is compulsory
       @param f one of no_argument, requires_argument, optional_argument
       @param v true or false -- display the option in usage
       to indicate what arguments should be supplied
    */
    BaseOption(const string& k, const string& ht, bool c, ArgFlag f, bool v): 
      key_(k), help_text_(ht), arg_flag_(f), 
      unset_(true), compulsory_(c), visible_(v) {}

    /**
       @return true if the option is compulsory
    */
    bool compulsory() { return compulsory_; }
    /**
       @return true if the option should be visible
    */
    bool visible() { return visible_; }
    /**
       @return true if the option requires an argument
    */
    bool required() { return arg_flag_ == requires_argument; }
    /**
       @return true if the option has an optional argument
    */
    bool optional() { return arg_flag_ == optional_argument; }
    /**
       @return true if the option has an argument at all
    */
    bool has_arg() { return arg_flag_ != no_argument; }
    /**
       @return true if the option has been set
    */
    bool set() { return !unset_; }
    /**
       @return true if the option remains unset
    */
    bool unset() { return unset_; }
    /*
      @param arg A command line argument to be compared against
      the list of possible keys for this option.
      @return True if a match is found.
    */
    bool matches(const string& arg);
    /*
      @return This options key string.
    */
    const string& key() const { return key_; }
    /*
      @return This options help text.
    */
    const string& help_text() const { return help_text_; }

    /*
      @param Sets the value for this option. Is overridden in the type
      specific template class Option.
    */
    virtual bool set_value(const string& vs) = 0;

    virtual ~BaseOption() {}

  private:
    string key_, help_text_;
    ArgFlag arg_flag_;

  protected:
    bool unset_, compulsory_, visible_;
  };

  ostream& operator<<(ostream &os, const BaseOption& o);


  /**
     Template class adding type specific behaviour to BaseOption. Define
     one of these per program supported option.
     @author Dave Flitney
     @version 1.0b, Nov., 2000.
     @see BaseOption
  */
  template<class T> class Option: public BaseOption {
  public:
    /** 
	@param k Comma seperated list of key aliases
	@param v Default value for this option
	@param ht Help text to be printed when outputting usage
	@param c If true then this option is compulsory
	@param f This options argument requirements
    */
    Option(const string& k, const T& v, const string& ht,
	   bool c, ArgFlag f = no_argument): 
      BaseOption(k, ht, c, f), default_(v), value_(v) {}
  /** 
	@param k Comma seperated list of key aliases
	@param v Default value for this option
	@param ht Help text to be printed when outputting usage
	@param c If true then this option is compulsory
	@param f This options argument requirements
    */
    Option(const string& k, const T& v, const string& ht,
	   bool c, ArgFlag f, bool vis): 
      BaseOption(k, ht, c, f, vis), default_(v), value_(v) {}


    /** 
	@param vs The value string which needs to be parsed to set
	this options value. The overloaded function string_to_T must be defined
	for type T.
    */
    bool set_value(const string& vs) { 
      if(string_to_T(value_, vs))
	unset_ = false;
      return !unset_;
    }

    /** 
	@param v The new value.
	Set the options type specific value. You should rarely need this
	method. Use of it means you either haven't planned your options well
	or you have some very complex option rules. You should probably issue
	a warning in your user interface if you call this as you're possibly
	overriding his/her prefered value.
    */
    bool set_T(const T& v) { 
      value_ = v;
      unset_ = false;
      return !unset_;
    }

    /**
       @return The options value.
    */
    const T& value() { return value_; }
    /** 
	@return The options default value.
    */
    const T& default_value() { return default_; }

    virtual ~Option() {}

  private:
    Option() {}
  
    T default_, value_;
  };

  /**
     Throw this exception if an error occured inside the Options package.
   */
  class X_OptionError: public std::exception {
  public:
    X_OptionError() throw() {};
    virtual const char * what() const throw() {
      return "There were errors parsing the command line!";   
    }
  };

  /**
     Throw this exception if no matching option was found during parsing.
   */
  class X_UnknownOption: public X_OptionError {
  public:
    X_UnknownOption(const string& s) throw(): 
      str_(s+":unknown option!") {};
    virtual const char * what() const throw() {
      return str_.c_str();
    }

  private:
    string str_;
  };

  /**
   */
  class X_AlreadySet: public X_OptionError {
  public:
    X_AlreadySet(const string& s) throw(): 
      str_(s+":already set!") {};
    virtual const char * what() const throw() {
      return str_.c_str();
    }

  private:
    string str_;
  };

  /**
     If an option should have had an argument but didn't then throw this
     exception.
   */
  class X_MissingArgument: public X_OptionError {
  public:
    X_MissingArgument(const string& s) throw(): 
      str_(s+":missing argument!") {};
    virtual const char * what() const throw() {
      return str_.c_str();
    }

  private:
    string str_;
  };

  /**
   */
  class X_InvalidArgument: public X_OptionError {
  public:
    X_InvalidArgument(const string& o, const string& v) throw(): 
      str_(o+":invalid argument "+v+"!") {};
    virtual const char * what() const throw() {
      return str_.c_str();
    }

  private:
    string str_;
  };

  /**
     A class for parsing command line arguments into Option objects. The 
     following example demonstrates the principle:
     @author Dave Flitney
     @version 1.0b, Nov., 2000.
     @see BaseOption
     @see Option
     <pre>
#include "options.h"

// $Id$ 

using namespace Utilities;

Option<bool> verbose(string("-V,--verbose"), false, 
		     string("switch on diagnostic messages"), 
		     false, BaseOption::no_argument);
Option<bool> help(string("-h,--help"), false,
		  string("display this message"),
		  false, BaseOption::no_argument);
Option<float> dof(string("-d,--dof"), 100.0,
		  string("number of degrees of freedom"),
		  true, BaseOption::requires_argument);
Option<string> mask(string("-m,--mask"), string("mask"),
		    string("brain mask volume"),
		    true, BaseOption::requires_argument);
Option<string> resid(string("-r,--res"), string("res4d"),
		     string("4d `residual-of-fit' image"),
		     true, BaseOption::requires_argument);
Option<int> segid(string("-s,--shared-seg-id"), -1,
		  "shared memory segment ID",
		  false, BaseOption::requires_argument);

string title = 
"opttst (Version 1.0)\n\n\
Copyright(c) 2000, University of Oxford\n\
Dave Flitney";

string examples =
"opttst --dof=<number> --mask=<filename> --res=<filename>\n\
opttst -d <number> -m <filename> -r <filename>\n\
opttst --verbose\n";

int main(unsigned int argc, char **argv) {

  OptionParser options(title, examples);

  try {

    options.add(verbose);
    options.add(help);
    options.add(segid);
    options.add(dof);
    options.add(mask);
    options.add(resid);

    for(unsigned int a = options.parse_command_line(argc, argv); 
	a < argc; a++)
      cout << argv[a] << endl;
  
    if(help.value() || 
       !options.check_compulsory_arguments())
      options.usage();

    if(verbose.value()) {
      cout << "verbose = " << verbose.value() << endl;
      cout << "help = " << help.value() << endl;
      cout << "segid = " << segid.value() << endl;
      cout << "dof = " << dof.value() << endl;
      cout << "mask = " << mask.value() << endl;
      cout << "resid = " << resid.value() << endl;
    }

  } catch(X_OptionError& e) {
    options.usage();
    cerr << endl << e.what() << endl;
  } catch(std::exception &e) {
    cerr << e.what() << endl;
  }    
}
     </pre>
  */
  class OptionParser {
  public:

    OptionParser(const string& p, const string& e): progname_(p), example_(e) {}

    /**
       @param o An option to be added to the parser
    */
    void add(BaseOption& o) { options_.push_back(&o); }

    void usage();
    /**
       @param verbose If set then this method will carp about any option which
       is marked as compulsory but hasn't been set
       @return true if all compulsory arguments have been set and false otherwise
    */
    bool check_compulsory_arguments(bool verbose=false);
    /**
       The parameters, argc and argv, should normally be those passed to
       main via the command line shell.
       @param argc The argument count.
       @param argv The vector of argument strings.
    */
    unsigned int parse_command_line(unsigned int argc, char **argv);

    virtual ~OptionParser() {}

  protected:
    /**
    */
    OptionParser() {}

  private:
    /**
       @param optstr A string which should match one of the option strings
       registered with the add method.
       @return Pointer to the matching option or NULL if a match wasn't found.
    */
    BaseOption* find_matching_option(const string& optstr);
    /**
       @param optstr A string which should match one of the option strings
       registered with the add method.
       @param valstr A string which can be used to set the options value
       if applicable.
       @return true on success.
    */
    unsigned int parse_option(const string& optstr, const string& valstr)
      throw(X_AlreadySet, X_UnknownOption, 
	    X_MissingArgument, X_InvalidArgument);
    /**
       @param str A string of the form --option[=value].
       @return true on success.
    */
    unsigned int parse_long_option(const string& str);

    string progname_, example_;

    typedef vector<BaseOption *> Options;
    Options options_;
  };

}
#endif