#include <string.h>

#include "minix.h"

#define TEST_BUFFER_BLOCKS 16
#define MAX_GOOD_BLOCKS 512

#define UPPER(size,n) ((size+((n)-1))/(n))
#define INODE_SIZE (sizeof(struct minix_inode))
#define INODE_BLOCKS UPPER(INODES,MINIX_INODES_PER_BLOCK)
#define INODE_BUFFER_SIZE (INODE_BLOCKS * BLOCK_SIZE)

#define BITS_PER_BLOCK (BLOCK_SIZE<<3)

static char * program_name = "mkfs";
static char * device_name = NULL;
static int DEV = -1;
static long BLOCKS = 0;
static int badblocks = 0;
static int namelen = 14;	/* default */
static int dirsize = 16;
static int magic = MINIX_SUPER_MAGIC;

static char root_block[BLOCK_SIZE] = "\0";

static char * inode_buffer = NULL;
#define Inode (((struct minix_inode *) inode_buffer)-1)
static char super_block_buffer[BLOCK_SIZE];
#define Super (*(struct minix_super_block *)super_block_buffer)
#define INODES ((unsigned long)Super.s_ninodes)
#define ZONES ((unsigned long)Super.s_nzones)
#define IMAPS ((unsigned long)Super.s_imap_blocks)
#define ZMAPS ((unsigned long)Super.s_zmap_blocks)
#define FIRSTZONE ((unsigned long)Super.s_firstdatazone)
#define ZONESIZE ((unsigned long)Super.s_log_zone_size)
#define MAXSIZE ((unsigned long)Super.s_max_size)
#define MAGIC (Super.s_magic)
#define NORM_FIRSTZONE (2+IMAPS+ZMAPS+INODE_BLOCKS)

static char inode_map[BLOCK_SIZE * MINIX_I_MAP_SLOTS];
static char zone_map[BLOCK_SIZE * MINIX_Z_MAP_SLOTS];

static unsigned short good_blocks_table[MAX_GOOD_BLOCKS];
static int used_good_blocks = 0;

static inline int bit(char *addr, unsigned int nr)
{
   return test_bit(nr,addr);
}
static inline int setbit(char *addr, unsigned int nr)
{
   return set_bit(nr, addr);
}
static inline int clrbit(char *addr, unsigned int nr)
{
   return clear_bit(nr, addr);
}

#define inode_in_use(x) (bit(inode_map,(x)))
#define zone_in_use(x) (bit(zone_map,(x)-FIRSTZONE+1))

#define mark_inode(x) (setbit(inode_map,(x)))
#define unmark_inode(x) (clrbit(inode_map,(x)))

#define mark_zone(x) (setbit(zone_map,(x)-FIRSTZONE+1))
#define unmark_zone(x) (clrbit(zone_map,(x)-FIRSTZONE+1))

static BOOL MinixFormat(UBYTE *VolumeName, ULONG DosType)
{
	struct minix_dir_entry *tmp;

	tmp = BufferBlock;
	tmp.inode = 1;
	strcpy(tmp.name, ".");
	tmp++;
	tmp.inode = 1;
	strcpy(tmp.name, "..");

	setup_tables();
	make_root_inode();
	mark_good_blocks();
	write_tables();
}

void setup_tables(void)
{
	int i;

	memset(inode_map,0xff,sizeof(inode_map));
	memset(zone_map,0xff,sizeof(zone_map));
	memset(super_block_buffer,0,BLOCK_SIZE);
	MAGIC = magic;
	ZONESIZE = 0;
	MAXSIZE = (7+512+512*512)*1024;
	ZONES = BLOCKS;
/* some magic nrs: 1 inode / 3 blocks */
	INODES = BLOCKS/3;
/* I don't want some off-by-one errors, so this hack... */
	if ((INODES & 8191) > 8188)
		INODES -= 5;
	if ((INODES & 8191) < 10)
		INODES -= 20;
	IMAPS = UPPER(INODES,BITS_PER_BLOCK);
	ZMAPS = 0;
	while (ZMAPS != UPPER(BLOCKS - NORM_FIRSTZONE,BITS_PER_BLOCK))
		ZMAPS = UPPER(BLOCKS - NORM_FIRSTZONE,BITS_PER_BLOCK);
	FIRSTZONE = NORM_FIRSTZONE;
	for (i = FIRSTZONE ; i<ZONES ; i++)
		unmark_zone(i);
	for (i = MINIX_ROOT_INO ; i<INODES ; i++)
		unmark_inode(i);
	inode_buffer = malloc(INODE_BUFFER_SIZE);
	if (!inode_buffer)
		die("Unable to allocate buffer for inodes");
	memset(inode_buffer,0,INODE_BUFFER_SIZE);
}

void write_tables(void)
{
	if (BLOCK_SIZE != lseek(DEV, BLOCK_SIZE, SEEK_SET))
		die("seek failed in write_tables");
	if (BLOCK_SIZE != write(DEV, super_block_buffer, BLOCK_SIZE))
		die("unable to write super-block");
	if (IMAPS*BLOCK_SIZE != write(DEV,inode_map,IMAPS*BLOCK_SIZE))
		die("Unable to write inode map");
	if (ZMAPS*BLOCK_SIZE != write(DEV,zone_map,ZMAPS*BLOCK_SIZE))
		die("Unable to write zone map");
	if (INODE_BUFFER_SIZE != write(DEV,inode_buffer,INODE_BUFFER_SIZE))
		die("Unable to write inodes");
}

void make_root_inode(void)
{
	struct minix_inode * inode = &Inode[MINIX_ROOT_INO];

	mark_inode(MINIX_ROOT_INO);
	inode->i_zone[0] = get_free_block();
	inode->i_nlinks = 2;
	inode->i_time = time(NULL);
	root_block[2*dirsize] = '\0';
	root_block[2*dirsize+1] = '\0';
	inode->i_size = 2*dirsize;

	inode->i_mode = S_IFDIR + 0755;
	write_block(inode->i_zone[0],root_block);
}

void write_block(int blk, char * buffer)
{
	if (blk*BLOCK_SIZE != lseek(DEV, blk*BLOCK_SIZE, SEEK_SET))
		die("seek failed in write_block");
	if (BLOCK_SIZE != write(DEV, buffer, BLOCK_SIZE))
		die("write failed in write_block");
}

int get_free_block(void)
{
	int blk;

	if (used_good_blocks+1 >= MAX_GOOD_BLOCKS)
		die("too many bad blocks");
	if (used_good_blocks)
		blk = good_blocks_table[used_good_blocks-1]+1;
	else
		blk = FIRSTZONE;
	while (blk < ZONES && zone_in_use(blk))
		blk++;
	if (blk >= ZONES)
		die("not enough good blocks");
	good_blocks_table[used_good_blocks] = blk;
	used_good_blocks++;
	return blk;
}

void mark_good_blocks(void)
{
	int blk;

	for (blk=0 ; blk < used_good_blocks ; blk++)
		mark_zone(good_blocks_table[blk]);
}