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- <?php
-
- class QRrsItem {
-
- public $mm;
- public $nn;
- public $alpha_to = array();
- public $index_of = array();
- public $genpoly = array();
- public $nroots;
- public $fcr;
- public $prim;
- public $iprim;
- public $pad;
- public $gfpoly;
-
-
- public function modnn($x)
- {
- while ($x >= $this->nn) {
- $x -= $this->nn;
- $x = ($x >> $this->mm) + ($x & $this->nn);
- }
-
- return $x;
- }
-
-
- public static function init_rs_char($symsize, $gfpoly, $fcr, $prim, $nroots, $pad)
- {
-
-
-
- $rs = null;
-
-
- if($symsize < 0 || $symsize > 8) return $rs;
- if($fcr < 0 || $fcr >= (1<<$symsize)) return $rs;
- if($prim <= 0 || $prim >= (1<<$symsize)) return $rs;
- if($nroots < 0 || $nroots >= (1<<$symsize)) return $rs;
- if($pad < 0 || $pad >= ((1<<$symsize) -1 - $nroots)) return $rs;
- $rs = new QRrsItem();
- $rs->mm = $symsize;
- $rs->nn = (1<<$symsize)-1;
- $rs->pad = $pad;
- $rs->alpha_to = array_fill(0, $rs->nn+1, 0);
- $rs->index_of = array_fill(0, $rs->nn+1, 0);
-
-
- $NN =& $rs->nn;
- $A0 =& $NN;
-
-
- $rs->index_of[0] = $A0;
- $rs->alpha_to[$A0] = 0;
- $sr = 1;
-
- for($i=0; $i<$rs->nn; $i++) {
- $rs->index_of[$sr] = $i;
- $rs->alpha_to[$i] = $sr;
- $sr <<= 1;
- if($sr & (1<<$symsize)) {
- $sr ^= $gfpoly;
- }
- $sr &= $rs->nn;
- }
-
- if($sr != 1){
-
- $rs = NULL;
- return $rs;
- }
-
- $rs->genpoly = array_fill(0, $nroots+1, 0);
-
- $rs->fcr = $fcr;
- $rs->prim = $prim;
- $rs->nroots = $nroots;
- $rs->gfpoly = $gfpoly;
-
- for($iprim=1;($iprim % $prim) != 0;$iprim += $rs->nn)
- ;
-
- $rs->iprim = (int)($iprim / $prim);
- $rs->genpoly[0] = 1;
-
- for ($i = 0,$root=$fcr*$prim; $i < $nroots; $i++, $root += $prim) {
- $rs->genpoly[$i+1] = 1;
-
- for ($j = $i; $j > 0; $j--) {
- if ($rs->genpoly[$j] != 0) {
- $rs->genpoly[$j] = $rs->genpoly[$j-1] ^ $rs->alpha_to[$rs->modnn($rs->index_of[$rs->genpoly[$j]] + $root)];
- } else {
- $rs->genpoly[$j] = $rs->genpoly[$j-1];
- }
- }
-
- $rs->genpoly[0] = $rs->alpha_to[$rs->modnn($rs->index_of[$rs->genpoly[0]] + $root)];
- }
-
-
- for ($i = 0; $i <= $nroots; $i++)
- $rs->genpoly[$i] = $rs->index_of[$rs->genpoly[$i]];
- return $rs;
- }
-
-
- public function encode_rs_char($data, &$parity)
- {
- $MM =& $this->mm;
- $NN =& $this->nn;
- $ALPHA_TO =& $this->alpha_to;
- $INDEX_OF =& $this->index_of;
- $GENPOLY =& $this->genpoly;
- $NROOTS =& $this->nroots;
- $FCR =& $this->fcr;
- $PRIM =& $this->prim;
- $IPRIM =& $this->iprim;
- $PAD =& $this->pad;
- $A0 =& $NN;
- $parity = array_fill(0, $NROOTS, 0);
- for($i=0; $i< ($NN-$NROOTS-$PAD); $i++) {
-
- $feedback = $INDEX_OF[$data[$i] ^ $parity[0]];
- if($feedback != $A0) {
-
-
-
-
- $feedback = $this->modnn($NN - $GENPOLY[$NROOTS] + $feedback);
-
- for($j=1;$j<$NROOTS;$j++) {
- $parity[$j] ^= $ALPHA_TO[$this->modnn($feedback + $GENPOLY[$NROOTS-$j])];
- }
- }
-
-
- array_shift($parity);
- if($feedback != $A0) {
- array_push($parity, $ALPHA_TO[$this->modnn($feedback + $GENPOLY[0])]);
- } else {
- array_push($parity, 0);
- }
- }
- }
- }
-
-
-
- class QRrs {
-
- public static $items = array();
-
-
- public static function init_rs($symsize, $gfpoly, $fcr, $prim, $nroots, $pad)
- {
- foreach(self::$items as $rs) {
- if($rs->pad != $pad) continue;
- if($rs->nroots != $nroots) continue;
- if($rs->mm != $symsize) continue;
- if($rs->gfpoly != $gfpoly) continue;
- if($rs->fcr != $fcr) continue;
- if($rs->prim != $prim) continue;
- return $rs;
- }
- $rs = QRrsItem::init_rs_char($symsize, $gfpoly, $fcr, $prim, $nroots, $pad);
- array_unshift(self::$items, $rs);
- return $rs;
- }
- }
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