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/*

 *  fat_file.h

 *

 *  Constants/data structures/prototypes for operations on "fat-file"

 *

 *  Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia

 *  Author: Eugeny S. Mints <Eugeny.Mints@oktet.ru>

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  @(#) fat_file.h,v 1.2 2002/03/28 13:52:49 joel Exp

 */

#ifndef __DOSFS_FAT_FILE_H__

#define __DOSFS_FAT_FILE_H__

#ifdef __cplusplus

extern "C" {

#endif

#include <rtems.h>

#include <rtems/libio_.h>

#include <time.h>

/* "fat-file" representation

 *

 * the idea is: fat-file is nothing but a cluster chain, any open fat-file is

 * represented in system by fat-file descriptor and has well-known

 * file interface:

 *

 * fat_file_open()

 * fat_file_close()

 * fat_file_read()

 * fat_file_write()

 *

 * Such interface hides the architecture of fat-file and represents it like

 * linear file

 */

typedef rtems_filesystem_node_types_t fat_file_type_t;

#define FAT_DIRECTORY     RTEMS_FILESYSTEM_DIRECTORY

#define FAT_FILE          RTEMS_FILESYSTEM_MEMORY_FILE

typedef struct fat_file_map_s

{

    unsigned32 file_cln;

    unsigned32 disk_cln;

    unsigned32 last_cln;

} fat_file_map_t;

/*

 * descriptor of a fat-file

 *

 * To each particular clusters chain

 */

typedef struct fat_file_fd_s

{

    Chain_Node      link;          /*

                                    * fat-file descriptors organized into hash;

                                    * collision lists are handled via link

                                    * field

                                    */

    unsigned32      links_num;     /*

                                    * the number of fat_file_open call on

                                    * this fat-file

                                    */

    unsigned32      ino;           /* inode, file serial number :)))) */

    fat_file_type_t fat_file_type;

    unsigned32      size_limit;

    unsigned32      fat_file_size; /* length  */

    unsigned32      info_cln;

    unsigned32      cln;

    unsigned16      info_ofs;

    unsigned char   first_char;

    unsigned8       flags;

    fat_file_map_t  map;

    time_t          mtime;

} fat_file_fd_t;

#define FAT_FILE_REMOVED  0x01

#define FAT_FILE_IS_REMOVED(p)\

    (((p)->flags & FAT_FILE_REMOVED) ? 1 : 0)

/* ioctl macros */

#define F_CLU_NUM  0x01

/*

 * Each file and directory on a MSDOS volume is unique identified by it

 * location, i.e. location of it 32 Bytes Directory Entry Structure. We can

 * distinguish them by cluster number it locates on and offset inside this

 * cluster. But root directory on any volumes (FAT12/16/32) has no 32 Bytes

 * Directory Entry Structure corresponded to it. So we assume 32 Bytes

 * Directory Entry Structure of root directory locates at cluster 1 (invalid

 * cluaster number) and offset 0

 */

#define FAT_ROOTDIR_CLUSTER_NUM 0x01 

#define FAT_FD_OF_ROOT_DIR(fat_fd)  \

  ((fat_fd->info_cln == FAT_ROOTDIR_CLUSTER_NUM ) && \

  (fat_fd->info_ofs == 0))

#define FAT_EOF           0x00

/* fat_construct_key --

 *     Construct key for hash access: convert (cluster num, offset) to

 *     (sector512 num, new offset) and than construct key as

 *     key = (sector512 num) << 4 | (new offset)

 *

 * PARAMETERS:

 *     cl       - cluster number

 *     ofs      - offset inside cluster 'cl'

 *     mt_entry - mount table entry

 *

 * RETURNS:

 *     constructed key

 */

static inline unsigned32

fat_construct_key(

    rtems_filesystem_mount_table_entry_t *mt_entry,

    unsigned32                            cl,

    unsigned32                            ofs)

{

    return ( ((fat_cluster_num_to_sector512_num(mt_entry, cl) +

              (ofs >> FAT_SECTOR512_BITS)) << 4)              +

              ((ofs >> 5) & (FAT_DIRENTRIES_PER_SEC512 - 1)) );

}

/* Prototypes for "fat-file" operations */

int

fat_file_open(rtems_filesystem_mount_table_entry_t  *mt_entry,

              unsigned32                             cln,

              unsigned32                             ofs,

              fat_file_fd_t                        **fat_fd);

int

fat_file_reopen(fat_file_fd_t *fat_fd);

int

fat_file_close(rtems_filesystem_mount_table_entry_t *mt_entry,

               fat_file_fd_t                        *fat_fd);

ssize_t

fat_file_read(rtems_filesystem_mount_table_entry_t *mt_entry,

              fat_file_fd_t                        *fat_fd,

              unsigned32                            start,

              unsigned32                            count,

              char                                 *buf);

ssize_t

fat_file_write(rtems_filesystem_mount_table_entry_t *mt_entry,

               fat_file_fd_t                        *fat_fd,

               unsigned32                            start,

               unsigned32                            count,

               const char                            *buf);

int

fat_file_extend(rtems_filesystem_mount_table_entry_t *mt_entry,

                fat_file_fd_t                        *fat_fd,

                unsigned32                            new_length,

                unsigned32                           *a_length);

int

fat_file_truncate(rtems_filesystem_mount_table_entry_t *mt_entry,

                  fat_file_fd_t                        *fat_fd,

                  unsigned32                            new_length);

int

fat_file_datasync(rtems_filesystem_mount_table_entry_t *mt_entry,

                  fat_file_fd_t                        *fat_fd);

int

fat_file_ioctl(rtems_filesystem_mount_table_entry_t *mt_entry,

               fat_file_fd_t                        *fat_fd,

               int                                   cmd,

               ...);

int

fat_file_size(rtems_filesystem_mount_table_entry_t *mt_entry,

              fat_file_fd_t                        *fat_fd);

void

fat_file_mark_removed(rtems_filesystem_mount_table_entry_t *mt_entry,

                      fat_file_fd_t                        *fat_fd);

#ifdef __cplusplus

}

#endif

#endif /* __DOSFS_FAT_FILE_H__ */