#ifndef __MSDIR__
#define __MSDIR__
/*
 *  MSDIR.H        Definitions for MS-DOS directory info
 *
 *  Copyright (c) 1991 Shal Farley
 *  		       Cheshire Engineering Corporation
 *  		       650 Sierra Madre Villa Avenue, Suite 201
 *  		       Pasadena, California 91107
 *  		       (818) 351-5493
 *                     (818) 351-8645 FAX
 *                     shal@alumni.caltech.edu
 *
 *  This software may be used and distributed for any purpose without license or
 *  royalty payments so long as the above copyright notice is preserved. If you
 *  have any comments, bug fixes, improvements, or new programs based upon this
 *  software I'd like to hear from you.
 */

#define SECTOR      512        /* "Always" 512 Bytes per sector (block) */

/*
 *  Seek offsets in the first sector (the boot sector)
 */
#define MSVH_BS     0x0000L        /* Boot Sector */
#define MSVH_SYSID  0x01FEL        /* Boot signature = 0xAA55 */


/*
 *  A structure holding information about the MS-DOS device
 */
typedef struct {
        long    nsTotal;        /*  2400 for 1.2 MB diskettes */
        FILE   *pFILE;          /*  Pointer to the file containing our info */
        UCHAR  *pDir;           /*  Pointer to Root Directory */
        UCHAR  *pFAT;           /*  Pointer to File Allocation Table */
        int     fDir;           /*  Directory needs to be written */
        int     fFAT;           /*  FAT needs to be written */
        int     fValid;         /*  Device has valid boot signature */
        int     fMaybe;         /*  Device has valid BIOS parameters */
        int     fRT11;          /*  Device has RT-11 signature */
        int     nsBoot;         /*  Sectors per Boot block, always 1 */
        int     nFATs;          /*  Always 2 */
        int     nsFAT;          /*  Sectors per FAT */
        int     nDirEntries;    /*  Entries in Root Directory (32 bytes ea) */
        int     nsCluster;      /*  Sectors per cluster, always a power of 2 */
        char    sName[MSDEVNAME_MAX]; /* RT-11 "DEV:FILNAM.TYP" of device */
} MSDEV;

/*
 *  MS-DOS Disk Structure:
 *      Boot block(s)           "Always" just one sector
 *      FAT(s)                  "Always" two copies, variable sized
 *      Root Directory          Variable sized
 *
 *  After reset the BIOS roms of a PC system will read in the bootstrap sector
 *  (sector 0) and jump to it. The first three bytes contain a jump to some code
 *  later in the sector. For "data" disks this code usually prints an error
 *  message and hangs. For "system" disks this code reads in the operating
 *  system.
 *
 *  The boot block also contains parameters, including the "BIOS Parameter
 *  Block", which tell the BIOS about the format of the media. The MSBS
 *  structure definition below describes the parameters.
 *
 *  Note that the parameters in the BS are declared as byte arrays, this is to
 *  ensure size conformance regardless of the host's data sizes. Copy any
 *  useful information to host format in the MSDEV structure. The same is true
 *  of the directory entries, copy any useful info to host format in MSFILE.
 */

/*
 *  The boot sector starts at byte 0 of block 0 of the disk.
 *
 *  See p34 of Microsoft MS-DOS Programmer's Reference: Version 5
 */
typedef struct {
    UCHAR   Jump[3];            /*  0  Jump to start of boot code */
    char    OemName[8];         /*  3  Name & Version of DOS */
    UCHAR   BytesPerSec[2];     /*  B  Always 512 */
    UCHAR   SecPerClust;        /*  D  1 or 2 for diskettes */
    UCHAR   ResSectors[2];      /*  E  Reserved for Bootstrap, typically 1 */
    UCHAR   FATs;               /* 10  Typically 2 or larger */
    UCHAR   RootDirEnts[2];     /* 11   224 for 1.2 MB diskettes */
    UCHAR   Sectors[2];         /* 13  2400 for 1.2 MB diskettes */
    UCHAR   Media;              /* 15  0xF9 for 1.2 MB diskettes */
    UCHAR   FATsecs[2];         /* 16     7 for 1.2 MB diskettes */
    UCHAR   SecPerTrack[2];     /* 18    15 for 1.2 MB diskettes */
    UCHAR   Heads[2];           /* 1A     2 for 1.2 MB diskettes */
    /*
     * Note: the fields below are new in MS-DOS 5.0 (some were present but
     * undocumented in prior versions). Test .BootSignature to see if the
     * extended fields are valid.
     */
    UCHAR   HiddenSecs[4];      /* 1C  Size of partition table */
    UCHAR   HugeSectors[4];     /* 20  if (disk > 32 MB) .Sectors = 0 */
    UCHAR   DriveNumber;        /* 24  (1st hard drive)? 0x80 : 0x00 */
    UCHAR   Reserved1;          /* 25  do not use */
    UCHAR   BootSignature;      /* 26  extended boot signature == 0x29 */
    UCHAR   VolumeID[4];        /* 27  Volume serial number */
    char    VolumeLabel[11];    /* 2B  Volume label */
    char    FileSysType[8];     /* 36  "FAT12   " or "FAT16   " */
} MSBS;


#define MSFN_DMAX   1           /* Maximum device field width */
#define MSFN_FMAX   8           /* Maximum name field width */
#define MSFN_TMAX   3           /* Maximum type field width */

/*
 *  Directory Entry structure
 *
 *  See p38 of Microsoft MS-DOS Programmer's Reference: Version 5
 */
typedef struct {
    char    Name[MSFN_FMAX];        /* File Name, in a subset of ASCII */
    char    Extension[MSFN_TMAX];   /* File Extension, " */
    UCHAR   Attributes;         /* Entry Status byte */
#define MSS_RONLY   (0x01)      /*  " Read-Only file */
#define MSS_HIDDEN  (0x02)      /*  " Hidden file */
#define MSS_SYSTEM  (0x04)      /*  " System file */
#define MSS_ROOT    (0x08)      /*  " Root directory entry w/ volume label */
#define MSS_DIR     (0x10)      /*  " Entry containing a subdirectory */
#define MSS_DIRTY   (0x20)      /*  " Dirty (aka "archive") */
    UCHAR   Reserved[10];       /* Reserved */
    UCHAR   Time[2];            /* File update time (little endian short) */
    UCHAR   Date[2];            /* File update date ( " ) */
    UCHAR   StartCluster[2];    /* Starting cluster number ( " ) */
    UCHAR   FileSize[4];        /* File size (little endian long) */
} MSDE;


/*
 *  12-bit FAT Entry structure
 */
typedef struct {
    UCHAR  b0;               /* bits 0-7 of first entry */
    UCHAR  b1;               /* bits 8-11 of first, 0-3 of second */
    UCHAR  b2;               /* bits 4-11 of second entry */
} MSFE;


/*
 *  Prototypes for our non-ANSI functions
 */

extern MSDEV *msdopen(/* devname */);
/*                              Set up the MS-DOS device info
 *    char   *devname;              "DEV:xxxxx" or "DEV:FILNAM.TYP:xxxxx"
 *                              Returns pointer to malloc'd MSDEV
 */

extern int msdclose(/* pD */);
/*                              Close the MS-DOS device
 *    MSDEV  *pD;
 *                              Returns 0 on success, EOF on error
 */


#endif /*__MSDIR__*/