/*****************************************************************************
 * Author:   Valient Gough <vgough@pobox.com>
 *
 *****************************************************************************
 * Copyright (c) 2004, Valient Gough
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _NameIO_incl_
#define _NameIO_incl_

#include <string>
#include <list>

#include <inttypes.h>

#include "base/Interface.h"
#include "base/shared_ptr.h"

namespace encfs {

class CipherV1;

class NameIO {
 public:
  typedef shared_ptr<NameIO>(*Constructor)(const Interface &iface,
                                           const shared_ptr<CipherV1> &cipher);

  struct Algorithm {
    std::string name;
    std::string description;
    Interface iface;
    bool needsStreamMode;
  };

  typedef std::list<Algorithm> AlgorithmList;
  static AlgorithmList GetAlgorithmList(bool includeHidden = false);

  static shared_ptr<NameIO> New(const Interface &iface,
                                const shared_ptr<CipherV1> &cipher);
  static shared_ptr<NameIO> New(const std::string &name,
                                const shared_ptr<CipherV1> &cipher);

  static bool Register(const char *name, const char *description,
                       const Interface &iface, Constructor constructor,
                       bool needsStreamMode, bool hidden = false);

  NameIO();
  virtual ~NameIO();

  virtual Interface interface() const = 0;

  void setChainedNameIV(bool enable);
  bool getChainedNameIV() const;
  void setReverseEncryption(bool enable);
  bool getReverseEncryption() const;

  std::string encodePath(const char *plaintextPath) const;
  std::string decodePath(const char *encodedPath) const;

  std::string encodePath(const char *plaintextPath, uint64_t *iv) const;
  std::string decodePath(const char *encodedPath, uint64_t *iv) const;

  virtual int maxEncodedNameLen(int plaintextNameLen) const = 0;
  virtual int maxDecodedNameLen(int encodedNameLen) const = 0;

  std::string encodeName(const char *plaintextName, int length) const;
  std::string decodeName(const char *encodedName, int length) const;

 protected:
  virtual int encodeName(const char *plaintextName, int length,
                         char *encodedName) const;
  virtual int decodeName(const char *encodedName, int length,
                         char *plaintextName) const;

  virtual int encodeName(const char *plaintextName, int length, uint64_t *iv,
                         char *encodedName) const = 0;
  virtual int decodeName(const char *encodedName, int length, uint64_t *iv,
                         char *plaintextName) const = 0;

 private:
  std::string recodePath(const char *path, int (NameIO::*codingLen)(int) const,
                         int (NameIO::*codingFunc)(const char *, int,
                                                   uint64_t *, char *) const,
                         uint64_t *iv) const;

  std::string _encodePath(const char *plaintextPath, uint64_t *iv) const;
  std::string _decodePath(const char *encodedPath, uint64_t *iv) const;
  std::string _encodeName(const char *plaintextName, int length) const;
  std::string _decodeName(const char *encodedName, int length) const;

  bool chainedNameIV;
  bool reverseEncryption;
};

/*
   Helper macros for creating temporary buffers with an optimization that
   below a given size (OptimizedSize) is allocated on the stack, and when a
   larger size is requested it is allocated on the heap.

   BUFFER_RESET should be called for the same name as BUFFER_INIT
 */
#define BUFFER_INIT(Name, OptimizedSize, Size) \
  char Name##_Raw[OptimizedSize];              \
  char *Name = Name##_Raw;                     \
  if (sizeof(Name##_Raw) < Size) {             \
    Name = new char[Size];                     \
  }                                            \
  memset(Name, 0, Size)

#define BUFFER_RESET(Name)    \
  do {                        \
    if (Name != Name##_Raw) { \
      delete[] Name;          \
      Name = Name##_Raw;      \
    }                         \
  } while (0)

}  // namespace encfs

#endif