text: /*
      ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                   2011,2012,2013 Giovanni Di Sirio.
  
      This file is part of ChibiOS/RT.
  
      ChibiOS/RT is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published by
      the Free Software Foundation; either version 3 of the License, or
      (at your option) any later version.
  
      ChibiOS/RT 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 General Public License for more details.
  
      You should have received a copy of the GNU General Public License
      along with this program.  If not, see <http://www.gnu.org/licenses/>.
  
                                        ---
  
      A special exception to the GPL can be applied should you wish to distribute
      a combined work that includes ChibiOS/RT, without being obliged to provide
      the source code for any proprietary components. See the file exception.txt
      for full details of how and when the exception can be applied.
  */
  
  /**
   * @file    chfiles.h
   * @brief   Data files.
   * @details This header defines abstract interfaces useful to access generic
   *          data files in a standardized way.
   *
   * @addtogroup data_files
   * @details This module define an abstract interface for generic data files by
   *          extending the @p BaseSequentialStream interface. Note that no code
   *          is present, data files are just abstract interface-like structures,
   *          you should look at the systems as to a set of abstract C++ classes
   *          (even if written in C). This system has the advantage to make the
   *          access to streams independent from the implementation logic.<br>
   *          The data files interface can be used as base class for high level
   *          object types such as an API for a File System implementation.
   * @{
   */
  
  #ifndef _CHFILES_H_
  #define _CHFILES_H_
  
  /**
   * @brief   No error return code.
   */
  #define FILE_OK         0
  
  /**
   * @brief   Error code from the file stream methods.
   */
  #define FILE_ERROR      0xFFFFFFFFUL
  
  /**
   * @brief   File offset type.
   */
  typedef uint32_t fileoffset_t;
  
  /**
   * @brief   BaseFileStream specific methods.
   */
  #define _base_file_stream_methods                                           \
    _base_sequential_stream_methods                                           \
    /* File close method.*/                                                   \
    uint32_t (*close)(void *instance);                                        \
    /* Get last error code method.*/                                          \
    int (*geterror)(void *instance);                                          \
    /* File get size method.*/                                                \
    fileoffset_t (*getsize)(void *instance);                                  \
    /* File get current position method.*/                                    \
    fileoffset_t (*getposition)(void *instance);                              \
    /* File seek method.*/                                                    \
    uint32_t (*lseek)(void *instance, fileoffset_t offset);
  
  /**
   * @brief   @p BaseFileStream specific data.
   * @note    It is empty because @p BaseFileStream is only an interface
   *          without implementation.
   */
  #define _base_file_stream_data                                              \
    _base_sequential_stream_data
  
  /**
   * @extends BaseSequentialStreamVMT
   *
   * @brief   @p BaseFileStream virtual methods table.
   */
  struct BaseFileStreamVMT {
    _base_file_stream_methods
  };
  
  /**
   * @extends BaseSequentialStream
   *
   * @brief   Base file stream class.
   * @details This class represents a generic file data stream.
   */
  typedef struct {
    /** @brief Virtual Methods Table.*/
    const struct BaseFileStreamVMT *vmt;
    _base_file_stream_data
  } BaseFileStream;
  
  /**
   * @name    Macro Functions (BaseFileStream)
   * @{
   */
  /**
   * @brief   Base file Stream close.
   * @details The function closes a file stream.
   *
   * @param[in] ip        pointer to a @p BaseFileStream or derived class
   * @return              The operation status.
   * @retval FILE_OK      no error.
   * @retval FILE_ERROR   operation failed.
   *
   * @api
   */
  #define chFileStreamClose(ip) ((ip)->vmt->close(ip))
  
  /**
   * @brief   Returns an implementation dependent error code.
   *
   * @param[in] ip        pointer to a @p BaseFileStream or derived class
   * @return              Implementation dependent error code.
   *
   * @api
   */
  #define chFileStreamGetError(ip) ((ip)->vmt->geterror(ip))
  
  /**
   * @brief   Returns the current file size.
   *
   * @param[in] ip        pointer to a @p BaseFileStream or derived class
   * @return              The file size.
   *
   * @api
   */
  #define chFileStreamGetSize(ip) ((ip)->vmt->getsize(ip))
  
  /**
   * @brief   Returns the current file pointer position.
   *
   * @param[in] ip        pointer to a @p BaseFileStream or derived class
   * @return              The current position inside the file.
   *
   * @api
   */
  #define chFileStreamGetPosition(ip) ((ip)->vmt->getposition(ip))
  
  /**
   * @brief   Moves the file current pointer to an absolute position.
   *
   * @param[in] ip        pointer to a @p BaseFileStream or derived class
   * @param[in] offset    new absolute position
   * @return              The operation status.
   * @retval FILE_OK      no error.
   * @retval FILE_ERROR   operation failed.
   *
   * @api
   */
  #define chFileStreamSeek(ip, offset) ((ip)->vmt->lseek(ip, offset))
  /** @} */
  
  #endif /* _CHFILES_H_ */
  
  /** @} */
  