DiskRam.cpp

/* ES40 emulator.
 * Copyright (C) 2007-2008 by the ES40 Emulator Project
 *
 * WWW    : http://sourceforge.net/projects/es40
 * E-mail : camiel@camicom.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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 * 
 * Although this is not required, the author would appreciate being notified of, 
 * and receiving any modifications you may make to the source code that might serve
 * the general public.
 */

/**
 * \file
 * Contains code to use a RAM disk.
 *
 * $Id: DiskRam.cpp,v 1.15 2008/03/02 09:42:52 iamcamiel Exp $
 *
 * X-1.15       Camiel Vanderhoeven                             02-MAR-2008
 *      Natural way to specify large numeric values ("10M") in the config file.
 *
 * X-1.14       Camiel Vanderhoeven                             13-JAN-2008
 *      Use determine_layout in stead of calc_cylinders.
 *
 * X-1.12       Camiel Vanderhoeven                             09-JAN-2008
 *      Save disk state to state file.
 *
 * X-1.11       Camiel Vanderhoeven                             06-JAN-2008
 *      Set default blocksize to 2048 for cd-rom devices.
 *
 * X-1.10       Camiel Vanderhoeven                             06-JAN-2008
 *      Support changing the block size (required for SCSI, ATAPI).
 *
 * X-1.9        Camiel Vanderhoeven                             04-JAN-2008
 *      64-bit file I/O.
 *
 * X-1.8        Camiel Vanderhoeven                             02-JAN-2008
 *      Cleanup.
 *
 * X-1.7        Camiel Vanderhoeven                             28-DEC-2007
 *      Throw exceptions rather than just exiting when errors occur.
 *
 * X-1.6        Camiel Vanderhoeven                             28-DEC-2007
 *      Keep the compiler happy.
 *
 * X-1.5        Camiel Vanderhoeven                             18-DEC-2007
 *      Byte-sized transfers for SCSI controller.
 *
 * X-1.4        Brian wheeler                                   17-DEC-2007
 *      Changed last cylinder number.
 *
 * X-1.3        Brian Wheeler                                   16-DEC-2007
 *      Fixed case of StdAfx.h.
 *
 * X-1.2        Camiel Vanderhoeven                             14-DEC-2007
 *      Free memory malloc'ed at destruction.
 *
 * X-1.1        Camiel Vanderhoeven                             12-DEC-2007
 *      Initial version in CVS.
 **/

#include "StdAfx.h" 
#include "DiskRam.h"

CDiskRam::CDiskRam(CConfigurator * cfg, CSystem * sys, CDiskController * c, int idebus, int idedev) : CDisk(cfg,sys,c,idebus,idedev)
{
  byte_size = myCfg->get_num_value("size",512*1024*1024);

  CHECK_ALLOCATION(ramdisk = malloc((size_t)byte_size));

  state.byte_pos = 0;

  sectors = 32;
  heads = 8;

  //calc_cylinders();
  determine_layout();

  model_number=myCfg->get_text_value("model_number","ES40RAMDISK");

  printf("%s: Mounted RAMDISK, %" LL "d %d-byte blocks, %" LL "d/%d/%d.\n",devid_string,byte_size/state.block_size,state.block_size,cylinders,heads,sectors);
}

CDiskRam::~CDiskRam(void)
{
  if (ramdisk)
  {
    printf("%s: RAMDISK freed.\n",devid_string);
    free(ramdisk);
    ramdisk = 0;
  }
}

bool CDiskRam::seek_byte(off_t_large byte)
{
  if (byte >=byte_size)
  {
    printf("%s: Seek beyond end of file!\n",devid_string);
    throw((int)1);
  }

  state.byte_pos = byte;
  return true;
}

size_t CDiskRam::read_bytes(void *dest, size_t bytes)
{
  if (state.byte_pos >=byte_size)
    return 0;

  while (state.byte_pos + bytes >= byte_size)
    bytes--;

  memcpy(dest,&(((char*)ramdisk)[state.byte_pos]),bytes);
  state.byte_pos += (unsigned long)bytes;
  return bytes;
}

size_t CDiskRam::write_bytes(void *src, size_t bytes)
{
  if (state.byte_pos >=byte_size)
    return 0;

  while (state.byte_pos + bytes >= byte_size)
    bytes--;

  memcpy(&(((char*)ramdisk)[state.byte_pos]),src,bytes);
  state.byte_pos += (unsigned long)bytes;
  return bytes;
}