/*

    File: file_tib.c

    Copyright (C) 2007-2010 Christophe GRENIER <grenier@cgsecurity.org>
  
    This software 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 the Free Software Foundation, Inc., 51
    Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "types.h"
#include "filegen.h"
#include "common.h"

#if defined(HAVE_FSEEKO) && !defined(__MINGW32__)
#define my_fseek fseeko
#else
#define my_fseek fseek
#endif

static void register_header_check_tib(file_stat_t *file_stat);
static int header_check_tib(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new);

const file_hint_t file_hint_tib= {
  .extension="tib",
  .description="Acronis True Image",
  .min_header_distance=0,
  .max_filesize=PHOTOREC_MAX_FILE_SIZE,
  .recover=1,
  .enable_by_default=1,
  .register_header_check=&register_header_check_tib
};

static const unsigned char tib2_footer[7]= {0x00, 0x00, 0x20, 0xa2, 0xb9, 0x24, 0xce};

static data_check_t data_check_tib2(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
{
  while(file_recovery->calculated_file_size + buffer_size/2  >= file_recovery->file_size &&
      file_recovery->calculated_file_size + 512 <= file_recovery->file_size + buffer_size/2)
  {
    const unsigned int i=file_recovery->calculated_file_size - file_recovery->file_size + buffer_size/2;
    file_recovery->calculated_file_size+=512;
    if(memcmp(&buffer[i + 512 - sizeof(tib2_footer)], tib2_footer, sizeof(tib2_footer))==0)
      return DC_STOP;
  }
  return DC_CONTINUE;
}

static void file_check_tib2(file_recovery_t *file_recovery)
{
  unsigned char*buffer=(unsigned char*)MALLOC(512);
  int64_t file_size=file_recovery->calculated_file_size-512;
  file_recovery->file_size = file_recovery->calculated_file_size;
  if(my_fseek(file_recovery->handle, file_size, SEEK_SET) < 0 ||
      fread(buffer, 1, 512, file_recovery->handle) != 512)
  {
    free(buffer);
    file_recovery->file_size=0;
    return;
  }
  if(memcmp(&buffer[512 - sizeof(tib2_footer)], tib2_footer, sizeof(tib2_footer))==0)
  {
    free(buffer);
    return;
  }

  for(; file_size>0; file_size-=512)
  {
    unsigned int i;
    if(my_fseek(file_recovery->handle, file_size, SEEK_SET) < 0 ||
	fread(buffer, 1, 512, file_recovery->handle) != 512)
    {
      free(buffer);
      file_recovery->file_size=0;
      return;
    }
    for(i=0; i<512 && buffer[i]==0; i++);
    if(i!=512)
    {
      file_recovery->file_size=file_size + 512;
      free(buffer);
      return ;
    }
  }
  free(buffer);
}

static int header_check_tib(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
{
  reset_file_recovery(file_recovery_new);
  file_recovery_new->extension=file_hint_tib.extension;
  return 1;
}

static int header_check_tib2(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
{
  reset_file_recovery(file_recovery_new);
  file_recovery_new->extension=file_hint_tib.extension;
  if(file_recovery_new->blocksize < 512)
    return 1;
  file_recovery_new->file_check=&file_check_tib2;
  file_recovery_new->data_check=&data_check_tib2;
  return 1;
}

static void register_header_check_tib(file_stat_t *file_stat)
{
  static const unsigned char tib_header[4]= { 0xb4, 0x6e, 0x68, 0x44};
  static const unsigned char tib2_header[7]= { 0xce, 0x24, 0xb9, 0xa2, 0x20, 0x00, 0x00};
  register_header_check(0, tib_header,sizeof(tib_header), &header_check_tib, file_stat);
  register_header_check(0, tib2_header,sizeof(tib2_header), &header_check_tib2, file_stat);
}
