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fat.cpp
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C/C++ Source or Header
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1993-11-17
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111 lines
/*
FIPS - the First nondestructive Interactive Partition Splitting program
Module fat.cpp
RCS - Header:
$Header: c:/daten/c/fips/source/cpp/RCS/fat.cpp 0.9.1.1 1993/11/17 17:51:05 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:
schaefer@rbg.informatik.th-darmstadt.de
*/
#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)
{
if (!global.quiet_mode) 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]);
}
}
if (!global.quiet_mode) printx ("OK\n\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;
if (!global.quiet_mode)
{
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)
error ("New Partition not empty: cluster %lu (FAT entry: %lu)",i,fat_entry);
}
if (!global.quiet_mode) printx ("OK\n");
}