/*
* (C) 2015 Jack Lloyd
* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_STREAM_MODE_H_
#define BOTAN_STREAM_MODE_H_

#include <botan/cipher_mode.h>
#include <botan/stream_cipher.h>

namespace Botan {

class BOTAN_PUBLIC_API(2,0) Stream_Cipher_Mode final : public Cipher_Mode
   {
   public:
      /**
      * @param cipher underyling stream cipher
      */
      explicit Stream_Cipher_Mode(StreamCipher* cipher) : m_cipher(cipher) {}

      size_t process(uint8_t buf[], size_t sz) override
         {
         m_cipher->cipher1(buf, sz);
         return sz;
         }

      void finish(secure_vector<uint8_t>& buf, size_t offset) override
         { return update(buf, offset); }

      size_t output_length(size_t input_length) const override { return input_length; }

      size_t update_granularity() const override { return 1; }

      size_t minimum_final_size() const override { return 0; }

      size_t default_nonce_length() const override { return 0; }

      bool valid_nonce_length(size_t nonce_len) const override
         { return m_cipher->valid_iv_length(nonce_len); }

      Key_Length_Specification key_spec() const override { return m_cipher->key_spec(); }

      std::string name() const override { return m_cipher->name(); }

      void clear() override
         {
         m_cipher->clear();
         reset();
         }

      void reset() override { /* no msg state */ }

   private:
      void start_msg(const uint8_t nonce[], size_t nonce_len) override
         {
         if(nonce_len > 0)
            {
            m_cipher->set_iv(nonce, nonce_len);
            }
         }

      void key_schedule(const uint8_t key[], size_t length) override
         {
         m_cipher->set_key(key, length);
         }

      std::unique_ptr<StreamCipher> m_cipher;
   };

}

#endif