210 lines
8.1 KiB
PHP
210 lines
8.1 KiB
PHP
<?php
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/*
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* PHP QR Code encoder
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*
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* Reed-Solomon error correction support
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*
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* Copyright (C) 2002, 2003, 2004, 2006 Phil Karn, KA9Q
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* (libfec is released under the GNU Lesser General Public License.)
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*
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* Based on libqrencode C library distributed under LGPL 2.1
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* Copyright (C) 2006, 2007, 2008, 2009 Kentaro Fukuchi <fukuchi@megaui.net>
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*
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* PHP QR Code is distributed under LGPL 3
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* Copyright (C) 2010 Dominik Dzienia <deltalab at poczta dot fm>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 3 of the License, or any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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class QRrsItem {
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public $mm; // Bits per symbol
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public $nn; // Symbols per block (= (1<<mm)-1)
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public $alpha_to = array(); // log lookup table
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public $index_of = array(); // Antilog lookup table
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public $genpoly = array(); // Generator polynomial
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public $nroots; // Number of generator roots = number of parity symbols
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public $fcr; // First consecutive root, index form
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public $prim; // Primitive element, index form
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public $iprim; // prim-th root of 1, index form
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public $pad; // Padding bytes in shortened block
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public $gfpoly;
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//----------------------------------------------------------------------
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public function modnn($x)
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{
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while ($x >= $this->nn) {
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$x -= $this->nn;
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$x = ($x >> $this->mm) + ($x & $this->nn);
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}
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return $x;
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}
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//----------------------------------------------------------------------
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public static function init_rs_char($symsize, $gfpoly, $fcr, $prim, $nroots, $pad)
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{
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// Common code for intializing a Reed-Solomon control block (char or int symbols)
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// Copyright 2004 Phil Karn, KA9Q
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// May be used under the terms of the GNU Lesser General Public License (LGPL)
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$rs = null;
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// Check parameter ranges
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if($symsize < 0 || $symsize > 8) return $rs;
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if($fcr < 0 || $fcr >= (1<<$symsize)) return $rs;
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if($prim <= 0 || $prim >= (1<<$symsize)) return $rs;
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if($nroots < 0 || $nroots >= (1<<$symsize)) return $rs; // Can't have more roots than symbol values!
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if($pad < 0 || $pad >= ((1<<$symsize) -1 - $nroots)) return $rs; // Too much padding
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$rs = new QRrsItem();
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$rs->mm = $symsize;
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$rs->nn = (1<<$symsize)-1;
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$rs->pad = $pad;
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$rs->alpha_to = array_fill(0, $rs->nn+1, 0);
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$rs->index_of = array_fill(0, $rs->nn+1, 0);
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// PHP style macro replacement ;)
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$NN =& $rs->nn;
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$A0 =& $NN;
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// Generate Galois field lookup tables
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$rs->index_of[0] = $A0; // log(zero) = -inf
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$rs->alpha_to[$A0] = 0; // alpha**-inf = 0
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$sr = 1;
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for($i=0; $i<$rs->nn; $i++) {
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$rs->index_of[$sr] = $i;
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$rs->alpha_to[$i] = $sr;
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$sr <<= 1;
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if($sr & (1<<$symsize)) {
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$sr ^= $gfpoly;
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}
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$sr &= $rs->nn;
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}
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if($sr != 1){
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// field generator polynomial is not primitive!
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$rs = NULL;
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return $rs;
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}
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/* Form RS code generator polynomial from its roots */
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$rs->genpoly = array_fill(0, $nroots+1, 0);
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$rs->fcr = $fcr;
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$rs->prim = $prim;
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$rs->nroots = $nroots;
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$rs->gfpoly = $gfpoly;
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/* Find prim-th root of 1, used in decoding */
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for($iprim=1;($iprim % $prim) != 0;$iprim += $rs->nn)
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; // intentional empty-body loop!
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$rs->iprim = (int)($iprim / $prim);
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$rs->genpoly[0] = 1;
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for ($i = 0,$root=$fcr*$prim; $i < $nroots; $i++, $root += $prim) {
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$rs->genpoly[$i+1] = 1;
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// Multiply rs->genpoly[] by @**(root + x)
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for ($j = $i; $j > 0; $j--) {
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if ($rs->genpoly[$j] != 0) {
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$rs->genpoly[$j] = $rs->genpoly[$j-1] ^ $rs->alpha_to[$rs->modnn($rs->index_of[$rs->genpoly[$j]] + $root)];
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} else {
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$rs->genpoly[$j] = $rs->genpoly[$j-1];
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}
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}
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// rs->genpoly[0] can never be zero
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$rs->genpoly[0] = $rs->alpha_to[$rs->modnn($rs->index_of[$rs->genpoly[0]] + $root)];
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}
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// convert rs->genpoly[] to index form for quicker encoding
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for ($i = 0; $i <= $nroots; $i++)
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$rs->genpoly[$i] = $rs->index_of[$rs->genpoly[$i]];
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return $rs;
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}
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//----------------------------------------------------------------------
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public function encode_rs_char($data, &$parity)
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{
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$MM =& $this->mm;
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$NN =& $this->nn;
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$ALPHA_TO =& $this->alpha_to;
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$INDEX_OF =& $this->index_of;
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$GENPOLY =& $this->genpoly;
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$NROOTS =& $this->nroots;
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$FCR =& $this->fcr;
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$PRIM =& $this->prim;
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$IPRIM =& $this->iprim;
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$PAD =& $this->pad;
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$A0 =& $NN;
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$parity = array_fill(0, $NROOTS, 0);
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for($i=0; $i< ($NN-$NROOTS-$PAD); $i++) {
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$feedback = $INDEX_OF[$data[$i] ^ $parity[0]];
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if($feedback != $A0) {
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// feedback term is non-zero
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// This line is unnecessary when GENPOLY[NROOTS] is unity, as it must
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// always be for the polynomials constructed by init_rs()
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$feedback = $this->modnn($NN - $GENPOLY[$NROOTS] + $feedback);
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for($j=1;$j<$NROOTS;$j++) {
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$parity[$j] ^= $ALPHA_TO[$this->modnn($feedback + $GENPOLY[$NROOTS-$j])];
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}
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}
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// Shift
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array_shift($parity);
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if($feedback != $A0) {
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array_push($parity, $ALPHA_TO[$this->modnn($feedback + $GENPOLY[0])]);
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} else {
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array_push($parity, 0);
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}
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}
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}
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}
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//##########################################################################
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class QRrs {
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public static $items = array();
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//----------------------------------------------------------------------
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public static function init_rs($symsize, $gfpoly, $fcr, $prim, $nroots, $pad)
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{
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foreach(self::$items as $rs) {
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if($rs->pad != $pad) continue;
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if($rs->nroots != $nroots) continue;
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if($rs->mm != $symsize) continue;
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if($rs->gfpoly != $gfpoly) continue;
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if($rs->fcr != $fcr) continue;
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if($rs->prim != $prim) continue;
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return $rs;
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}
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$rs = QRrsItem::init_rs_char($symsize, $gfpoly, $fcr, $prim, $nroots, $pad);
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array_unshift(self::$items, $rs);
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return $rs;
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}
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} |