// FAT disk structure definitions
//
// Author: J. van Wijk
//
// JvW  04-12-97   Initial version, derived from DFSHPFS
//
#ifndef    DFSFAT_H
   #define DFSFAT_H

#define FAT_MAXCLUST   ((ULONG) 0x0ffffff5)     // found max for FAT32
#define FAT_MINEOFCL   ((ULONG) 0x0ffffff8)


#define SG_FAT12       2
#define SV_FAT12       (char)0xff,(char)0xff
typedef struct s_fat12                         // FAT disk structure 12-bit
{
   BYTE                 MediaType;
   char                 Signature[SG_FAT12];
   BYTE                 Reserved[509];
} S_FAT12;                                      // end of struct "s_fat12"

#define SG_FAT16       3
#define SV_FAT16       (char)0xff,(char)0xff,(char)0xff
typedef struct s_fat16                         // FAT disk structure 16-bit
{
   BYTE                 MediaType;
   char                 Signature[SG_FAT16];
   BYTE                 Reserved[508];
} S_FAT16;                                      // end of struct "s_fat16"


#define SG_FAT32       7
#define SV_FAT32       (char)0xff,(char)0xff,(char)0xff, \
                       (char)0xff,(char)0xff,(char)0xff,(char)0xff
typedef struct s_fat32                         // FAT disk structure 32-bit
{
   BYTE                 MediaType;
   char                 Signature[SG_FAT32];
   BYTE                 Reserved[504];
} S_FAT32;                                      // end of struct "s_fat32"

#if defined (WIN32)                             // force 16-bit on MSC++
   #define DFS_BITFIELD  unsigned short
#else
   #define DFS_BITFIELD  unsigned
#endif

typedef struct s_time
{
   DFS_BITFIELD       twosecs : 5;
   DFS_BITFIELD       minutes : 6;
   DFS_BITFIELD       hours   : 5;
} S_TIME;


typedef struct s_date
{
   DFS_BITFIELD       day     : 5;
   DFS_BITFIELD       month   : 4;
   DFS_BITFIELD       year    : 7;
} S_DATE;


typedef union s_datim                           // combined date/time int
{
   S_TIME              t;
   S_DATE              d;
   USHORT              u;
} S_DATIM;                                      // end of union "s_datim"


#define FAT_DIRFREE    0x00                     // Fat dir free entrie
#define FAT_DIRDEL     0xe5                     // Fat dir deleted entry
#define FAT_DIRDOT     0x2e                     // Fat dir . or .. entry
#define FAT_DIRENT     16                       // Fat dir entries per sector
#define FAT_NSIZE      8
#define FAT_ESIZE      3
typedef struct s_fatdir
{
   char                Name[ FAT_NSIZE];        // Name part 8.3
   char                Ext[ FAT_ESIZE];         // Ext. part 8.3
   BYTE                FatAttrib;               // FAT attribute bits
   BYTE                Vlcase;                  // VFAT lowercase flag
   BYTE                Vctime_ms;               // VFAT creation time millisec
   S_DATIM             Vctime;                  // VFAT creation time
   S_DATIM             Vcdate;                  // VFAT creation date
   S_DATIM             Vadate;                  // VFAT last-access time
   union
   {
      USHORT           OS2EA;                   // OS/2 EA index in EA DATA
      USHORT           clustHi;                 // High word of 32-bit cluster
   };                                           // end of union
   S_DATIM             time;                    // Last modification time
   S_DATIM             date;                    // Last modification date
   USHORT              clust;                   // First cluster number
   ULONG               fsize;                   // File size
} S_FATDIR;                                     // end of struct "s_fatdir"

#define VFAT_ATTRIB    0x0f                     // fixed attrib  value lfn's
#define VFAT_CLUSTR    0x00                     // fixed cluster value lfn's
#define VFAT_SLOT_1    0x40                     // bit-mask for 1st lfn slot
typedef struct s_vfslot
{
   BYTE                SlotId;                  //
   USHORT              lfn5[5];                 // 1st group unicode chars lfn
   BYTE                FatAttrib;               // FAT attribute bits
   BYTE                Vzero;                   // reserved, must be zero
   BYTE                Vcheck;                  // VFAT 8.3 alias checksum
   USHORT              lfn6[6];                 // 2nd group unicode chars lfn
   USHORT              clust;                   // First cluster number (zero!)
   USHORT              lfn2[2];                 // 3rd group unicode chars lfn
} S_VFSLOT;                                     // end of struct "s_vfslot"


typedef union s_vfat
{
   S_FATDIR            d;                       // FAT directory entry
   S_VFSLOT            v;                       // VFAT lsn entry
} S_VFAT;                                       // end of union "s_vfat"

/*
                <preceeding files...>
                <slot #3, id = 0x43, characters = "h is long">
                <slot #2, id = 0x02, characters = "xtension whic">
                <slot #1, id = 0x01, characters = "My Big File.E">
                <directory entry, name = "MYBIGFIL.EXT">
*/

#define SV_EACLUST   ((USHORT) 0x4145)
#define FAT_EAOFFS   ((USHORT) 30)              // offset to 1st eadata
typedef struct s_eaclust
{
   USHORT              signature;               // signature 'EA' = 0x4145
   USHORT              index;                   // EA-index, matching OS2EA
   ULONG               reserv1;                 // unknown, assume 0 for now
   char                fname[12];               // null-terminated filename
   BYTE                reserv2[6];              // unknown
   USHORT              ealength;                // total length of EA data
   BYTE                reserv3[2];              // unknown
   S_EABLK             eadata[1];               // first of EA-data sequence
} S_EACLUST;                                    // end of struct "s_eaclust"

/*
   Note: The eadata[1] field actualy is a repeating, variable length
         structure for each EA belonging to the file.
*/

#define SV_EAINDEX   ((USHORT) 0x4445)
#define EAI_SIZE       240
typedef struct s_eaindex
{
   USHORT              signature;               // signature 'EA' = 0x4145
   BYTE                reserv1[30];             // unknown, seems to be 0
   USHORT              base[EAI_SIZE];          // Base values for Map
   USHORT              mapsector[1];            // First of Map sectors
} S_EAINDEX;                                    // end of struct "s_eaclust"

/*
   Note: above EAINDEX structure is defined here at it's minimum size being
         two sectors like seen on 1 sector/cluster volumes (diskettes)
         On a harddisk it is usualy 1 cluster, depending on the number of
         EA's actualy present.
*/

#endif