/*
       FIPS - the First nondestructive Interactive Partition Splitting program

       Module logdr_st.cpp

       RCS - Header:
       $Header: c:/daten/fips/source/main/RCS/logdr_str.cpp 1.4 1995/01/19 00:00:54 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 <string.h>
#include "types.h"
#include "logdr_st.h"

/* ----------------------------------------------------------------------- */
/* Extract Bios Parameter Block from boot sector                           */
/* ----------------------------------------------------------------------- */

void bios_parameter_block::get (boot_sector *boot_sector)
{
       byte *bp = boot_sector->data;

       memcpy (jump_instruction,bp,3);
       memcpy (oem_name,bp+3,8);
       oem_name[8]=0;
       bytes_per_sector = *(bp+0xb) | (*(bp+0xc) << 8);
       sectors_per_cluster = *(bp+0xd);
       reserved_sectors = *(bp+0xe) | (*(bp+0xf) << 8);
       no_of_fats = *(bp+0x10);
       no_of_rootdir_entries = *(bp+0x11) | (*(bp+0x12) << 8);
       no_of_sectors = *(bp+0x13) | (*(bp+0x14) << 8);
       media_descriptor = *(bp+0x15);
       sectors_per_fat16 = *(bp+0x16) | (*(bp+0x17) << 8);
       sectors_per_track = *(bp+0x18) | (*(bp+0x19) << 8);
       drive_heads = *(bp+0x1a) | (*(bp+0x1b) << 8);
       hidden_sectors = (dword) *(bp+0x1c) | ((dword) *(bp+0x1d) << 8) | ((dword) *(bp+0x1e) << 16) | ((dword) *(bp+0x1f) << 24);
       no_of_sectors_long = (dword) *(bp+0x20) | ((dword) *(bp+0x21) << 8) | ((dword) *(bp+0x22) << 16) | ((dword) *(bp+0x23) << 24);
       bp += 0x24;
       if (sectors_per_fat16 == 0) {
               /* Might be a FAT32 partition */
               sectors_per_fat = (dword)
                       (((dword) bp[3] << 24) | ((dword) bp[2] << 16) | (bp[1] << 8) | bp[0]);
               bp += 4;
               flags = (bp[1] << 8) | bp[0]; bp += 2;
               version[0] = *bp++;
               version[1] = *bp++;
               root_cluster = (dword)
                       (((dword) bp[3] << 24) | ((dword) bp[2] << 16) | (bp[1] << 8) | bp[0]);
               bp += 4;
               info_sector = ((bp[1] << 8) | bp[0]); bp += 2;
               backup_boot = ((bp[1] << 8) | bp[0]); bp += 2;
               bp += 12; /* Skip over reserved bytes */
       } else {
               sectors_per_fat = sectors_per_fat16;
               root_cluster = 0;
       }
       phys_drive_no = *bp; bp += 2;
       signature = *bp++;
       serial_number = (dword)
               (bp[0] | (bp[1] << 16) | ((dword) bp[2] << 16) | ((dword) bp[3] << 24));
               bp += 4;
       memcpy (volume_label,bp,11); bp += 11;
       volume_label[11] = 0;
       memcpy (file_system_id,bp,8); bp += 8;
       file_system_id[8] = 0;

}

/* ----------------------------------------------------------------------- */
/* Write Bios Parameter Block back into boot sector                        */
/* ----------------------------------------------------------------------- */

void bios_parameter_block::put (boot_sector *boot_sector)
{
       byte *bp = boot_sector->data;

       memcpy (bp,jump_instruction,3);
       memcpy (bp+3,oem_name,8);
       *(bp+0xb) = bytes_per_sector & 0xff;
       *(bp+0xc) = (bytes_per_sector >> 8) & 0xff;
       *(bp+0xd) = sectors_per_cluster;
       *(bp+0xe) = reserved_sectors & 0xff;
       *(bp+0xf) = (reserved_sectors >> 8) & 0xff;
       *(bp+0x10) = no_of_fats;
       *(bp+0x11) = no_of_rootdir_entries & 0xff;
       *(bp+0x12) = (no_of_rootdir_entries >> 8) & 0xff;
       *(bp+0x13) = no_of_sectors & 0xff;
       *(bp+0x14) = (no_of_sectors >> 8) & 0xff;
       *(bp+0x15) = media_descriptor;
       if (sectors_per_fat16 == 0) {
               *(bp+0x16) = 0;
               *(bp+0x17) = 0;
       } else {
               *(bp+0x16) = sectors_per_fat & 0xff;
               *(bp+0x17) = (sectors_per_fat >> 8) & 0xff;
       }
       *(bp+0x18) = sectors_per_track & 0xff;
       *(bp+0x19) = (sectors_per_track >> 8) & 0xff;
       *(bp+0x1a) = drive_heads & 0xff;
       *(bp+0x1b) = (drive_heads >> 8) & 0xff;
       *(bp+0x1c) = hidden_sectors & 0xff;
       *(bp+0x1d) = (hidden_sectors >> 8) & 0xff;
       *(bp+0x1e) = (hidden_sectors >> 16) & 0xff;
       *(bp+0x1f) = (hidden_sectors >> 24) & 0xff;
       *(bp+0x20) = no_of_sectors_long & 0xff;
       *(bp+0x21) = (no_of_sectors_long >> 8) & 0xff;
       *(bp+0x22) = (no_of_sectors_long >> 16) & 0xff;
       *(bp+0x23) = (no_of_sectors_long >> 24) & 0xff;
       bp += 0x24;
       if (sectors_per_fat16 == 0) {
               *bp++ = sectors_per_fat & 0xff;
               *bp++ = (sectors_per_fat >> 8) & 0xff;
               *bp++ = (sectors_per_fat >> 16) & 0xff;
               *bp++ = (sectors_per_fat >> 24) & 0xff;

               *bp++ = flags & 0xff;
               *bp++ = (flags >> 8) & 0xff;

               *bp++ = version[0];
               *bp++ = version[1];

               *bp++ = root_cluster & 0xff;
               *bp++ = (root_cluster >> 8) & 0xff;
               *bp++ = (root_cluster >> 16) & 0xff;
               *bp++ = (root_cluster >> 24) & 0xff;

               *bp++ = info_sector & 0xff;
               *bp++ = (info_sector >> 8) & 0xff;

               *bp++ = backup_boot & 0xff;
               *bp++ = (backup_boot >> 8) & 0xff;

               bp += 12; /* Skip over reserved bytes */
       }
       *bp   = phys_drive_no; bp += 2;
       *bp++ = signature;
       *bp++ = serial_number & 0xff;
       *bp++ = (serial_number >> 8) & 0xff;
       *bp++ = (serial_number >> 16) & 0xff;
       *bp++ = (serial_number >> 24) & 0xff;
       memcpy (bp,volume_label,11); bp += 11;
       memcpy (bp,file_system_id,8); bp += 8;
}

/* ----------------------------------------------------------------------- */
/* Extract some misc. drive parameters from BPB                            */
/* ----------------------------------------------------------------------- */

void logical_drive_info::get (const bios_parameter_block &bpb)
{
       start_fat1 = bpb.reserved_sectors;
       start_fat2 = start_fat1 + bpb.sectors_per_fat;
       start_rootdir = start_fat2 + bpb.sectors_per_fat;
       if (bpb.no_of_rootdir_entries == 0) start_data = start_rootdir;
       else start_data = start_rootdir + (bpb.no_of_rootdir_entries - 1) / 16 + 1;
       if (bpb.sectors_per_cluster == 0) no_of_clusters = 0;
       else {
               no_of_clusters = ((bpb.no_of_sectors ? bpb.no_of_sectors : bpb.no_of_sectors_long) - start_data) / bpb.sectors_per_cluster;
               if (bpb.sectors_per_fat16 == 0) no_of_clusters -= 2;
       }
};

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