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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.rtems.com/license/LICENSE.
*
* @(#) $Id$
*/
#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
{
uint32_t file_cln;
uint32_t disk_cln;
uint32_t 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
*/
uint32_t links_num; /*
* the number of fat_file_open call on
* this fat-file
*/
uint32_t ino; /* inode, file serial number :)))) */
fat_file_type_t fat_file_type;
uint32_t size_limit;
uint32_t fat_file_size; /* length */
uint32_t info_cln;
uint32_t cln;
uint16_t info_ofs;
unsigned char first_char;
uint8_t 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 uint32_t
fat_construct_key(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t cl,
uint32_t 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,
uint32_t cln,
uint32_t 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,
uint32_t start,
uint32_t count,
char *buf);
ssize_t
fat_file_write(rtems_filesystem_mount_table_entry_t *mt_entry,
fat_file_fd_t *fat_fd,
uint32_t start,
uint32_t count,
const char *buf);
int
fat_file_extend(rtems_filesystem_mount_table_entry_t *mt_entry,
fat_file_fd_t *fat_fd,
uint32_t new_length,
uint32_t *a_length);
int
fat_file_truncate(rtems_filesystem_mount_table_entry_t *mt_entry,
fat_file_fd_t *fat_fd,
uint32_t 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__ */
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