partition.h

/**
 * Ext2read
 * File: partition.h
 **/
/**
 * Copyright (C) 2005 by Manish Regmi   (regmi dot manish at gmail.com)
 *
 * 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 2 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, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 **/
/*
 * This file is partially derived from file fdisk.h of util linux program.
 *
 * Copyright (C) 1992  A. V. Le Blanc (LeBlanc@mcc.ac.uk)
 *
 * For detailed old history, see older versions.
 * Contributions before 2001 by faith@cs.unc.edu, Michael Bischoff,
 * LeBlanc@mcc.ac.uk, martin@cs.unc.edu, leisner@sdsp.mc.xerox.com,
 * esr@snark.thyrsus.com, aeb@cwi.nl, quinlan@yggdrasil.com,
 * fasten@cs.bonn.edu, orschaer@cip.informatik.uni-erlangen.de,
 * jj@sunsite.mff.cuni.cz, fasten@shw.com, ANeuper@GUUG.de,
 * kgw@suse.de, kalium@gmx.de, dhuggins@linuxcare.com,
 * michal@ellpspace.math.ualberta.ca and probably others.
 */

#ifndef __PARTITION_H
#define __PARTITION_H

#include "platform.h"
#include "ext2read.h"

struct MBRpartition {
	unsigned char boot_ind;         /* 0x80 - active */
	unsigned char head;             /* starting head */
	unsigned char sector;           /* starting sector */
	unsigned char cyl;              /* starting cylinder */
	unsigned char sys_ind;          /* What partition type */
	unsigned char end_head;         /* end head */
	unsigned char end_sector;       /* end sector */
	unsigned char end_cyl;          /* end cylinder */
	unsigned char start4[4];        /* starting sector counting from 0 */
	unsigned char size4[4];         /* nr of sectors in partition */
};

#define SECTOR_SIZE	512

#define pt_offset(b, n)	((struct MBRpartition *)((b) + 0x1be + (n) * sizeof(struct MBRpartition)))

/* A valid partition table sector ends in 0x55 0xaa */
static INLINE unsigned int 
part_table_flag(unsigned char *b) 
{
	return ((uint) b[510]) + (((uint) b[511]) << 8);
}

static INLINE int 
valid_part_table_flag(unsigned char *b) 
{
	return (b[510] == 0x55 && b[511] == 0xaa);
}

/* start_sect and nr_sects are stored little endian on all machines */
/* moreover, they are not aligned correctly */
static INLINE void 
store4_little_endian(unsigned char *cp, unsigned int val) 
{
	cp[0] = (val & 0xff);
	cp[1] = ((val >> 8) & 0xff);
	cp[2] = ((val >> 16) & 0xff);
	cp[3] = ((val >> 24) & 0xff);
}

static INLINE unsigned int 
read4_little_endian(unsigned char *cp) 
{
	return (uint)(cp[0]) + ((uint)(cp[1]) << 8) \
		+ ((uint)(cp[2]) << 16) + ((uint)(cp[3]) << 24);
}

static INLINE void 
set_start_sect(struct MBRpartition *p, unsigned int start_sect) 
{
	store4_little_endian(p->start4, start_sect);
}

static INLINE unsigned int 
get_start_sect(struct MBRpartition *p) 
{
	return read4_little_endian(p->start4);
}

static INLINE void 
set_nr_sects(struct MBRpartition *p, unsigned int nr_sects) 
{
	store4_little_endian(p->size4, nr_sects);
}

static INLINE unsigned int 
get_nr_sects(struct MBRpartition *p) 
{
	return read4_little_endian(p->size4);
}

#endif //__PARTITION_H