GopherProxy

/*
FIPS - the First nondestructive Interactive Partition Splitting program

Module fat.cpp

RCS - Header:
$Header: c:/daten/fips/source/main/RCS/fat.cpp 1.1 1994/05/25 22:19:46 schaefer Exp schaefer $

Copyright (C) 1993 Arno Schaefer

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., 675 Mass Ave, Cambridge, MA 02139, USA.

Report problems and direct all questions to:

[email protected]
*/

#include "logdr_st.h"
#include "global.h"
#include "fat.h"

fat::fat (class logical_drive *logical_drive,int number)
{
fat::logical_drive = logical_drive;
fat::number = number;
buffer = new sector;
start_sector = (number == 1) ? logical_drive->info().start_fat1 : logical_drive->info().start_fat2;
sector_in_buffer = -1;
}

dword fat16::next_cluster (dword cluster_number)
{
dword sector = cluster_number / 256;
int offset = (cluster_number % 256) * 2;

if (sector != sector_in_buffer) read_sector (sector);

return ((dword) buffer->data[offset] | ((dword) buffer->data[offset + 1] << 8));
}

void fat::read_sector (dword sector)
{
if (logical_drive->read_sector (sector + start_sector,buffer))
if (number == 1)
error ("Error reading FAT 1");
else
error ("Error reading FAT 2");
sector_in_buffer = sector;
}

void fat16::check_against (class fat16 *fat2)
{
printx ("Checking FAT ... ");

for (int i=0;i<logical_drive->bpb().sectors_per_fat;i++)
{
read_sector (i);
fat2->read_sector (i);

for (int j=0;j<512;j++) if (buffer->data[j] != fat2->buffer->data[j])
error ("FAT copies differ: FAT 1 -> %02Xh, FAT 2 -> %02Xh in sector %u, byte %u",buffer->data[j],fat2->buffer->data[j],i,j);

if (i == 0)
{
if (buffer->data[0] != 0xf8)
if (!global.override_media_descriptor)
error ("Wrong Media Descriptor Byte in FAT: %02Xh",buffer->data[0]);
if ((buffer->data[1] != 0xff) || (buffer->data[2] != 0xff) || (buffer->data[3] != 0xff))
warning ("Wrong FAT entries 1 & 2: %02X %02X %02X %02X",buffer->data[0],buffer->data[1],buffer->data[2],buffer->data[3]);
}
}
printx ("OK\n");
}

void fat16::check_empty (dword new_start_sector)
{
dword first_cluster = (new_start_sector - logical_drive->info().start_data) / logical_drive->bpb().sectors_per_cluster + 2;

dword last_cluster = logical_drive->info().no_of_clusters + 1;

if (last_cluster > ((dword) 256 * logical_drive->bpb().sectors_per_fat - 1)) last_cluster = (dword) 256 * logical_drive->bpb().sectors_per_fat - 1;

printx ("First Cluster: %lu\nLast Cluster: %lu\n\n",first_cluster,last_cluster);
printx ("Testing if empty ... ");

for (dword i=first_cluster;i <= last_cluster;i++)
{
dword fat_entry = next_cluster (i);

if (fat_entry != 0) if (fat_entry != 0xfff7)
{
if (fat_entry == 0xffff)
{
error ("New Partition not empty: cluster %lu ( FAT entry: <EOF> )",i);
}
else
{
error ("New Partition not empty: cluster %lu ( FAT entry: %lu )",i,fat_entry);
}
}
}
printx ("OK\n");
}

dword fat16::min_cluster (void)
{
dword first_cluster = 2;

dword last_cluster = logical_drive->info().no_of_clusters + 1;

if (last_cluster > ((dword) 256 * logical_drive->bpb().sectors_per_fat - 1)) last_cluster = (dword) 256 * logical_drive->bpb().sectors_per_fat - 1;

printx ("Searching for free space ... ");

dword i;

for (i=last_cluster;i >= first_cluster;i--)
{
dword fat_entry = next_cluster (i);

if (fat_entry != 0) if (fat_entry != 0xfff7)
{
i++;
break;
}
}
printx ("OK\n\n");
return (i);
}