// vfat.h
// Author: Josh Holtrop
// Date: 03/11/04
// Modified: 03/22/04

#ifndef __HOS_VFAT__
#define __HOS_VFAT__ __HOS_VFAT__

#include "hos_defines.h"
#include "fs/vfs.h"

#define VFAT_FAT12_EOCL 0x0FF8		// end-of-cluster chain reached if FatValue >= EOCL
#define VFAT_FAT16_EOCL 0xFFF8
#define VFAT_FAT32_EOCL 0x0FFFFFF8

#define VFAT_FAT12_EOC 0x0FFF		// end-of-cluster chain value
#define VFAT_FAT16_EOC 0xFFFF
#define VFAT_FAT32_EOC 0x0FFFFFFF

#define VFAT_FAT12_BAD 0x0FF7		// bad cluster mark
#define VFAT_FAT16_BAD 0xFFF7
#define VFAT_FAT32_BAD 0x0FFFFFF7

#define VFAT_DIRENTRY_FREE 0xE5
#define VFAT_DIRENTRY_FREE_LAST 0x00

typedef struct
{
	byte	jmpBoot[3];		// {0xEB, 0x??, 0x90} or {0xE9, 0x??, 0x??}
	char	OEMName[8];		// any 8-char string (def. "MSWIN4.1")
	word	bytesPerSector;		// 512 (default), 1024, 2048, 4096
	byte	sectorsPerCluster;	// 1 (default), 2, 4, 8, 16, 32, 64, 128
	word	reservedSectors;	// 1 (fat12/16), 32 (fat32)
	byte	numFATs;		// 2
	word	rootEntries;		// number of 32-byte root directory entries (224 for 1440k floppy) - 0 for fat32
	word	totalSectors16;		// total number of sectors in volume (2880 for floppy) - 0 for fat32
	byte	media;			// >= 0xF0 valid, 0xF8 (default non-removable), 0xF0 (default removable), must match lsb of FAT[0]
	word	sectorsPerFAT16;	// number of sectors in FAT (9 for floppy)
	word	sectorsPerTrack;	// (18 for floppy)
	word	numHeads;		// number of heads (2 for floppy)
	dword	hiddenSectors;		// 0
	dword	totalSectors32;		// 0, non-zero for fat32 volumes

	/* FAT32 specific members */
	dword	sectorsPerFAT32;	// number of sectors in a fat for fat32 volumes
	word	extFlags;		// bits 0-3 active fat, bit 7 {0 = mirror all FATs, 1 = only use 1 FAT}
	word	fsVersion;		// fat32 version (0:0)
	dword	rootCluster;		// first cluster of root directory (default 2)
	word	fsInfo;			// sector number of FSINFO block (default 1)
	word	bootCopy;		// sector of backup boot record (default 6)
} __attribute__ ((packed)) vfat_bpb;

typedef struct
{
	dword	leadSignature;		// 0x41615252
	byte	reserved1[480];
	dword	structSignature;	// 0x61417272
	dword	lastFree;		// last known free cluster (0xFFFFFFFF == unknown)
	dword	nextFree;		// start looking for free clusters here (0xFFFFFFFF == unknown)
	byte	reserved2[12];
	dword	trailSignature;		// 0xAA550000
} __attribute__ ((packed)) vfat_fsinfo;

typedef struct
{
	char	fileName[8];		// file name, 8 char. max, pad w/ spaces
	char	fileExt[3];		// file extension, 3 char. max, pad w/ spaces
	byte	attributes;		// file attributes, read-only, etc.
	byte	reserved;		// 0
	byte	timeTenths;		// 0-199
	word	time;			// time of creation
	word	date;			// date of creation
	word	adate;			// last accessed date
	word	clusterHigh;		// 0 for fat12/16
	word	wtime;			// last write time
	word	wdate;			// last write date
	word	clusterLow;		// LSW of first cluster of file data
	dword	fileSize;
} __attribute__ ((packed)) vfat_dirEntry;

typedef struct
{
	byte	order;
	word	name0_4[5];		// filename - first 5 characters (unicode)
	byte	attributes;		// must be VFAT_LONG_NAME
	byte	type;			// 0 = part of long name
	byte	checksum;		// checksum of short entry at end of long entry set
	word	name5_10[6];		// filename - next 6 characters (unicode)
	word	clusterLow;		// 0
	word	name11_12[2];		// filename - next 2 characters
} __attribute__ ((packed)) vfat_lfnEntry;

#define VFAT_READ_ONLY 0x01
#define VFAT_HIDDEN 0x02
#define VFAT_SYSTEM 0x04
#define VFAT_VOLUME 0x08
#define VFAT_DIRECTORY 0x10
#define VFAT_ARCHIVE 0x20

#define VFAT_LONG_NAME 0x0F		// VFAT_READ_ONLY | VFAT_HIDDEN | VFAT_SYSTEM | VFAT_VOLUME
#define VFAT_ATTR_MASK 0x3F		// VFAT_READ_ONLY | VFAT_HIDDEN | VFAT_SYSTEM | VFAT_VOLUME | VFAT_DIRECTORY | VFAT_ARCHIVE

#define VFAT_ORDER_MASK 0x40

/*
 * Illegal file name characters:
 *  Values less than 0x20 except for 0x05. 0x05 signifies that the actual filename character is 0xE5
 *  0x22 ("), 0x2A (*)
 *  0x2E (.), 0x2F (/), 0x3A (:)
 *  0x3C (<), 0x3E (>), 0x3F (?), 0x5C (\), 0x7C (|)
 * The following are illegal in 8.3 but legal in LFN:
 *  0x2B (+), 0x2C (,), 0x3B (;), 0x3D (=), 0x5B ([), 0x5D (])
 */

//From Microsoft's FAT32 File System Specification
typedef struct
{
	dword	diskSize;
	byte	sectorsPerCluster;
} DSKSZTOSECPERCLUS;

// sector[510] == 0x55
// sector[511] == 0xAA

int	vfat_identify(vfat_bpb *bpb);
int	vfat_format(Volume *vol);
FILE	*vfat_open(char *fileName, dword attributes, Volume *vol);
vfat_bpb *vfat_getBootSector(Volume *vol);
int	vfat_close(FILE *fp);
byte	*vfat_loadFAT(Volume *vol, vfat_bpb *bpb)

#endif