scan_name.h

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/*
* SCAN Name Abstraction
* (C) 2008,2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
 
#ifndef BOTAN_SCAN_NAME_H_
#define BOTAN_SCAN_NAME_H_
 
#include <botan/types.h>
#include <string>
#include <vector>
 
namespace Botan {
 
/**
A class encapsulating a SCAN name (similar to JCE conventions)
http://www.users.zetnet.co.uk/hopwood/crypto/scan/
*/
class SCAN_Name final
   {
   public:
      /**
      * Create a SCAN_Name
      * @param algo_spec A SCAN-format name
      */
      explicit SCAN_Name(const char* algo_spec);
 
      /**
      * Create a SCAN_Name
      * @param algo_spec A SCAN-format name
      */
      explicit SCAN_Name(const std::string& algo_spec);
 
      /**
      * @return original input string
      */
      const std::string& to_string() const { return m_orig_algo_spec; }
 
      /**
      * @return algorithm name
      */
      const std::string& algo_name() const { return m_alg_name; }
 
      /**
      * @return number of arguments
      */
      size_t arg_count() const { return m_args.size(); }
 
      /**
      * @param lower is the lower bound
      * @param upper is the upper bound
      * @return if the number of arguments is between lower and upper
      */
      bool arg_count_between(size_t lower, size_t upper) const
         { return ((arg_count() >= lower) && (arg_count() <= upper)); }
 
      /**
      * @param i which argument
      * @return ith argument
      */
      std::string arg(size_t i) const;
 
      /**
      * @param i which argument
      * @param def_value the default value
      * @return ith argument or the default value
      */
      std::string arg(size_t i, const std::string& def_value) const;
 
      /**
      * @param i which argument
      * @param def_value the default value
      * @return ith argument as an integer, or the default value
      */
      size_t arg_as_integer(size_t i, size_t def_value) const;
 
      /**
      * @param i which argument
      * @return ith argument as an integer
      */
      size_t arg_as_integer(size_t i) const;
 
      /**
      * @return cipher mode (if any)
      */
      std::string cipher_mode() const
         { return (m_mode_info.size() >= 1) ? m_mode_info[0] : ""; }
 
      /**
      * @return cipher mode padding (if any)
      */
      std::string cipher_mode_pad() const
         { return (m_mode_info.size() >= 2) ? m_mode_info[1] : ""; }
 
   private:
      std::string m_orig_algo_spec;
      std::string m_alg_name;
      std::vector<std::string> m_args;
      std::vector<std::string> m_mode_info;
   };
 
// This is unrelated but it is convenient to stash it here
template<typename T>
std::vector<std::string> probe_providers_of(const std::string& algo_spec,
                                            const std::vector<std::string>& possible = { "base" })
   {
   std::vector<std::string> providers;
   for(auto&& prov : possible)
      {
      std::unique_ptr<T> o(T::create(algo_spec, prov));
      if(o)
         {
         providers.push_back(prov); // available
         }
      }
   return providers;
   }
 
}
 
#endif