/******************************************************************************
** Functions by Derrick Sobodash
** http://www.cinnamonpirate.com/
** Submitted to ROM Hacking.net on July 3, 2006
******************************************************************************/

/******************************************************************************
** sfam_read()
*******************************************************************************
** syntax: string sfam_read(string filename)
*******************************************************************************
** Reads a Super Famicom/Nintendo ROM to a string and deinterleaves it if
** not already deinterleaved. The header wil be stripped if it exists.
** Returns the ROM as a string.
******************************************************************************/

function sfam_read($infile)
{

  if(!file_exists($infile))
    die("Error: sfam_read(): Unable to open $infile\r\n\r\n");

  $fddump = file_read($infile);
  $header = "";

  // "SUPERUFO"
  $ufotest = substr($fddump, 0x8, 8);
  // "GAME DOCTOR SF 3"
  $gd3test = substr($fddump, 0, 0x10);

  if(substr($fddump, 0x1e8, 4) == "NSRT")
    $header = substr($fddump, 0, SNES_HEADER);

  if(strlen($fddump) % (32 * KBYTE) != 0)
    $fddump = substr($fddump, SNES_HEADER);

  $test = array();
  $test['inverse']  = punpack(substr($fddump, 0x7fdc, 2));
  $test['checksum'] = punpack(substr($fddump, 0x7fde, 2));
  $test['romstate'] = ord(substr($fddump, 0x7fd5, 1)) % 0x10;

  if($test['inverse'] + $test['checksum'] == 0xffff && $test['romstate'] % 2 == 0)
    return($fddump);

  else if($test['inverse'] + $test['checksum'] == 0xffff && $test['romstate'] % 2 != 0)
  {

    $chart_20mbit = array(
        1,   3,   5,   7,   9,  11,  13,  15,  17,  19,  21,  23,  25,  27,  29,
       31,  33,  35,  37,  39,  41,  43,  45,  47,  49,  51,  53,  55,  57,  59,
       61,  63,  65,  67,  69,  71,  73,  75,  77,  79,  64,  66,  68,  70,  72,
       74,  76,  78,  32,  34,  36,  38,  40,  42,  44,  46,  48,  50,  52,  54,
       56,  58,  60,  62,   0,   2,   4,   6,   8,  10,  12,  14,  16,  18,  20,
       22,  24,  26,  28,  30
    );

    $chart_24mbit = array(
        1,   3,   5,   7,   9,  11,  13,  15,  17,  19,  21,  23,  25,  27,  29,
       31,  33,  35,  37,  39,  41,  43,  45,  47,  49,  51,  53,  55,  57,  59,
       61,  63,  65,  67,  69,  71,  73,  75,  77,  79,  81,  83,  85,  87,  89,
       91,  93,  95,  64,  66,  68,  70,  72,  74,  76,  78,  80,  82,  84,  86,
       88,  90,  92,  94,   0,   2,   4,   6,   8,  10,  12,  14,  16,  18,  20,
       22,  24,  26,  28,  30,  32,  34,  36,  38,  40,  42,  44,  46,  48,  50,
       52,  54,  56,  58,  60,  62
    );

    $chart_48mbit = array(
      129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157,
      159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187,
      189, 191, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 152,
      154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182,
      184, 186, 188, 190,   1,   3,   5,   7,   9,  11,  13,  15,  17,  19,  21,
       23,  25,  27,  29,  31,  33,  35,  37,  39,  41,  43,  45,  47,  49,  51,
       53,  55,  57,  59,  61,  63,  65,  67,  69,  71,  73,  75,  77,  79,  81,
       83,  85,  87,  89,  91,  93,  95,  97,  99, 101, 103, 105, 107, 109, 111,
      113, 115, 117, 119, 121, 123, 125, 127,   0,   2,   4,   6,   8,  10,  12,
       14,  16,  18,  20,  22,  24,  26,  28,  30,  32,  34,  36,  38,  40,  42,
       44,  46,  48,  50,  52,  54,  56,  58,  60,  62,  64,  66,  68,  70,  72,
       74,  76,  78,  80,  82,  84,  86,  88,  90,  92,  94,  96,  98, 100, 102,
      104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126
    );

    if(strlen($fddump) == 512 * KBYTE * 5 && $ufotest != "SUPERUFO")
    {

      $chunks = array();
      
      for($i = 0; $i < 0x50; $i ++)
        $chunks[$i] = substr($fddump, $i * (32 * KBYTE), (32 * KBYTE));

      $deinterleave = "";

      for($i = 0; $i < 0x50; $i ++)
        $deinterleave .= $chunks[array_search($i, $chart_20mbit)];

      return($deinterleave);

    }

    else if(strlen($fddump) == 512 * KBYTE * 6 && $ufotest != "SUPERUFO")
    {

      $chunks = array();

      for($i = 0; $i < 0x60; $i ++)
        $chunks[$i] = substr($fddump, $i * (32 * KBYTE), (32 * KBYTE));

      $deinterleave = "";

      for($i = 0; $i < 0x60; $i ++)
        $deinterleave .= $chunks[array_search($i, $chart_24mbit)];

      return($deinterleave);

    }

    else if(strlen($fddump) == 512 * KBYTE * 12 && $ufotest != "SUPERUFO")
    {

      $chunks = array();

      for($i = 0; $i < 0xc0; $i ++)
        $chunks[$i] = substr($fddump, $i * (32 * KBYTE), (32 * KBYTE));

      $deinterleave = "";

      for($i = 0; $i < 0xc0; $i ++)
        $deinterleave .= $chunks[array_search($i, $chart_48mbit)];

      return($deinterleave);

    }

    else
    {

      $chunks = strlen($fddump) / (32 * KBYTE);
      $deinterleave = "";

      for($i = 0; $i < ($chunks / 2); $i ++)
      {

    $deinterleave .= substr($fddump, ($i + ($chunks / 2)) * (32 * KBYTE), (32 * KBYTE));
        $deinterleave .= substr($fddump, $i * (32 * KBYTE), (32 * KBYTE));

      }

      return($deinterleave);

    }

  }

  $test['inverse']  = punpack(substr($fddump, 0xffdc, 2));
  $test['checksum'] = punpack(substr($fddump, 0xffde, 2));
  $test['romstate'] = ord(substr($fddump, 0xffd5, 1)) % 0x10;

  if($test['inverse'] + $test['checksum'] == 0xffff && $test['romstate'] % 2 != 0)
    return($fddump);

  else if($test['romstate'] % 2 != 0)
    return($fddump);

  else
    die("Error: sfam_read(): Supplied ROM file does not appear to be Super Nintendo ROM\r\n\r\n");

}