diff options
Diffstat (limited to 'libs/phpqrcode/lib/PHPQRCode/QRrsItem.php')
| -rw-r--r-- | libs/phpqrcode/lib/PHPQRCode/QRrsItem.php | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/libs/phpqrcode/lib/PHPQRCode/QRrsItem.php b/libs/phpqrcode/lib/PHPQRCode/QRrsItem.php new file mode 100644 index 00000000..ce63a8c3 --- /dev/null +++ b/libs/phpqrcode/lib/PHPQRCode/QRrsItem.php @@ -0,0 +1,162 @@ +<?php +/** + * QRrsItem.php + * + * Created by arielferrandini + */ + +namespace PHPQRCode; + +class QRrsItem { + + public $mm; // Bits per symbol + public $nn; // Symbols per block (= (1<<mm)-1) + public $alpha_to = array(); // log lookup table + public $index_of = array(); // Antilog lookup table + public $genpoly = array(); // Generator polynomial + public $nroots; // Number of generator roots = number of parity symbols + public $fcr; // First consecutive root, index form + public $prim; // Primitive element, index form + public $iprim; // prim-th root of 1, index form + public $pad; // Padding bytes in shortened block + 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) + { + // Common code for intializing a Reed-Solomon control block (char or int symbols) + // Copyright 2004 Phil Karn, KA9Q + // May be used under the terms of the GNU Lesser General Public License (LGPL) + + $rs = null; + + // Check parameter ranges + if($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 $rs; // Can't have more roots than symbol values! + if($pad < 0 || $pad >= ((1<<$symsize) -1 - $nroots)) return $rs; // Too much padding + + $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); + + // PHP style macro replacement ;) + $NN =& $rs->nn; + $A0 =& $NN; + + // Generate Galois field lookup tables + $rs->index_of[0] = $A0; // log(zero) = -inf + $rs->alpha_to[$A0] = 0; // alpha**-inf = 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){ + // field generator polynomial is not primitive! + $rs = NULL; + return $rs; + } + + /* Form RS code generator polynomial from its roots */ + $rs->genpoly = array_fill(0, $nroots+1, 0); + + $rs->fcr = $fcr; + $rs->prim = $prim; + $rs->nroots = $nroots; + $rs->gfpoly = $gfpoly; + + /* Find prim-th root of 1, used in decoding */ + for($iprim=1;($iprim % $prim) != 0;$iprim += $rs->nn) + ; // intentional empty-body loop! + + $rs->iprim = (int)($iprim / $prim); + $rs->genpoly[0] = 1; + + for ($i = 0,$root=$fcr*$prim; $i < $nroots; $i++, $root += $prim) { + $rs->genpoly[$i+1] = 1; + + // Multiply rs->genpoly[] by @**(root + x) + 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] can never be zero + $rs->genpoly[0] = $rs->alpha_to[$rs->modnn($rs->index_of[$rs->genpoly[0]] + $root)]; + } + + // convert rs->genpoly[] to index form for quicker encoding + for ($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 term is non-zero + + // This line is unnecessary when GENPOLY[NROOTS] is unity, as it must + // always be for the polynomials constructed by init_rs() + $feedback = $this->modnn($NN - $GENPOLY[$NROOTS] + $feedback); + + for($j=1;$j<$NROOTS;$j++) { + $parity[$j] ^= $ALPHA_TO[$this->modnn($feedback + $GENPOLY[$NROOTS-$j])]; + } + } + + // Shift + array_shift($parity); + if($feedback != $A0) { + array_push($parity, $ALPHA_TO[$this->modnn($feedback + $GENPOLY[0])]); + } else { + array_push($parity, 0); + } + } + } +}
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