/* Copyright (C) 2008  Emmanuel Varoquaux

   This file is part of XOS.

   This program 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.

   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 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/>. */

/* Implementation des macros definis dans le document 'FAT: General Overview of
 * On-Disk Format' (Microsoft Extensible Firmware Initiative - FAT32 File
 * System Specification). *
 * Les conventions de nommage definies dans ce document ont ete conservees. */

#ifndef VFAT_FAT_INFO_H
#define VFAT_FAT_INFO_H

#define FALSE 0
#define TRUE  1

#include "vfat_fat_info_struct.h"

typedef unsigned short WORD;
typedef unsigned long DWORD;

/* types de FAT */
enum {FAT12, FAT16, FAT32};

int init_fat_info(struct vfat_fat_info_struct *fat_info, const void *buf);

static inline unsigned long FirstSectorofCluster(const struct vfat_fat_info_struct *fat_info, unsigned long N)
{
  return ((N - 2) * fat_info->boot_sect.BPB_SecPerClus) + fat_info->FirstDataSector;
}

static inline unsigned long FATOffset(const struct vfat_fat_info_struct *fat_info, unsigned long N)
{
  if (fat_info->FATType == FAT12)
    return N + (N / 2);
  else if (fat_info->FATType == FAT16)
    return N * 2;
  else
    return N * 4;
}

static inline unsigned long ThisFATSecNum(const struct vfat_fat_info_struct *fat_info, unsigned long N)
{
  return fat_info->boot_sect.BPB_ResvdSecCnt + (FATOffset(fat_info, N) / fat_info->boot_sect.BPB_BytsPerSec);
}

static inline unsigned long ThisFATEntOffset(const struct vfat_fat_info_struct *fat_info, unsigned long N)
{
  return FATOffset(fat_info, N) % fat_info->boot_sect.BPB_BytsPerSec;
}

unsigned long get_FATClusEntryVal(const unsigned char SecBuff[], const struct vfat_fat_info_struct *fat_info, unsigned long N);

void set_FATClusEntryVal(unsigned char SecBuff[], const struct vfat_fat_info_struct *fat_info, unsigned long N, unsigned long FATClusEntryVal);

int IsEOF(const struct vfat_fat_info_struct *fat_info, unsigned long FATContent);

#endif