program_options_lite.h

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/* The copyright in this software is being made available under the BSD
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 * and contributor rights, including patent rights, and no such rights are
 * granted under this license.
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 * Copyright (c) 2010-2017, ITU/ISO/IEC
 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
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 *    this list of conditions and the following disclaimer.
 *  * 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.
 *  * Neither the name of the ITU/ISO/IEC nor the names of its contributors may
 *    be used to endorse or promote products derived from this software without
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 */
#include <iostream>
#include <sstream>
#include <string>
#include <list>
#include <map>

#ifndef __PROGRAM_OPTIONS_LITE__
#define __PROGRAM_OPTIONS_LITE__



namespace df
{
  namespace program_options_lite
  {
    struct Options;

    struct ParseFailure : public std::exception
    {
      ParseFailure(std::string arg0, std::string val0) throw()
      : arg(arg0), val(val0)
      {}

      ~ParseFailure() throw() {};

      std::string arg;
      std::string val;

      const char* what() const throw() { return "Option Parse Failure"; }
    };

    struct ErrorReporter
    {
      ErrorReporter() : is_errored(0) {}
      virtual ~ErrorReporter() {}
      virtual std::ostream& error(const std::string& where);
      virtual std::ostream& warn(const std::string& where);
      bool is_errored;
    };

    extern ErrorReporter default_error_reporter;

    void doHelp(std::ostream& out, Options& opts, unsigned columns = 80);
    std::list<const char*> scanArgv(Options& opts, unsigned argc, const char* argv[], ErrorReporter& error_reporter = default_error_reporter);
    void setDefaults(Options& opts);
    void parseConfigFile(Options& opts, const std::string& filename, ErrorReporter& error_reporter = default_error_reporter);

    struct OptionBase
    {
      OptionBase(const std::string& name, const std::string& desc)
      : opt_string(name), opt_desc(desc)
      {};

      virtual ~OptionBase() {}

      /* parse argument arg, to obtain a value for the option */
      virtual void parse(const std::string& arg, ErrorReporter&) = 0;
      /* set the argument to the default value */
      virtual void setDefault() = 0;

      std::string opt_string;
      std::string opt_desc;
    };

    template<typename T>
    struct Option : public OptionBase
    {
      Option(const std::string& name, T& storage, T default_val, const std::string& desc)
      : OptionBase(name, desc), opt_storage(storage), opt_default_val(default_val)
      {}

      void parse(const std::string& arg, ErrorReporter&);

      void setDefault()
      {
        opt_storage = opt_default_val;
      }

      T& opt_storage;
      T opt_default_val;
    };

    /* Generic parsing */
    template<typename T>
    inline void
    Option<T>::parse(const std::string& arg, ErrorReporter&)
    {
      std::istringstream arg_ss (arg,std::istringstream::in);
      arg_ss.exceptions(std::ios::failbit);
      try
      {
        arg_ss >> opt_storage;
      }
      catch (...)
      {
        throw ParseFailure(opt_string, arg);
      }
    }

    /* string parsing is specialized -- copy the whole string, not just the
     * first word */
    template<>
    inline void
    Option<std::string>::parse(const std::string& arg, ErrorReporter&)
    {
      opt_storage = arg;
    }

    struct OptionFunc : public OptionBase
    {
      typedef void (Func)(Options&, const std::string&, ErrorReporter&);

      OptionFunc(const std::string& name, Options& parent_, Func *func_, const std::string& desc)
      : OptionBase(name, desc), parent(parent_), func(func_)
      {}

      void parse(const std::string& arg, ErrorReporter& error_reporter)
      {
        func(parent, arg, error_reporter);
      }

      void setDefault()
      {
        return;
      }

    private:
      Options& parent;
      Func* func;
    };

    class OptionSpecific;
    struct Options
    {
      ~Options();

      OptionSpecific addOptions();

      struct Names
      {
        Names() : opt(0) {};
        ~Names()
        {
          if (opt)
          {
            delete opt;
          }
        }
        std::list<std::string> opt_long;
        std::list<std::string> opt_short;
        OptionBase* opt;
      };

      void addOption(OptionBase *opt);

      typedef std::list<Names*> NamesPtrList;
      NamesPtrList opt_list;

      typedef std::map<std::string, NamesPtrList> NamesMap;
      NamesMap opt_long_map;
      NamesMap opt_short_map;
    };

    /* Class with templated overloaded operator(), for use by Options::addOptions() */
    class OptionSpecific
    {
    public:
      OptionSpecific(Options& parent_) : parent(parent_) {}

      template<typename T>
      OptionSpecific&
      operator()(const std::string& name, T& storage, T default_val, const std::string& desc = "")
      {
        parent.addOption(new Option<T>(name, storage, default_val, desc));
        return *this;
      }

      OptionSpecific&
      operator()(const std::string& name, OptionFunc::Func *func, const std::string& desc = "")
      {
        parent.addOption(new OptionFunc(name, parent, func, desc));
        return *this;
      }
    private:
      Options& parent;
    };

  } /* namespace: program_options_lite */
} /* namespace: df */


#endif