FormatInformation.php — WP 2FA – Two-factor authentication for WordPress 4.0.0

wp-2fa / includes / classes / bacon / bacon-qr-code / src / Common / FormatInformation.php

wp-2fa / includes / classes / bacon / bacon-qr-code / src / Common Last commit date

BitArray.php 1 week ago BitMatrix.php 1 week ago BitUtils.php 1 week ago CharacterSetEci.php 1 week ago EcBlock.php 1 week ago EcBlocks.php 1 week ago ErrorCorrectionLevel.php 1 week ago FormatInformation.php 1 week ago Mode.php 1 week ago ReedSolomonCodec.php 1 week ago Version.php 1 week ago index.php 1 week ago

FormatInformation.php

133 lines

1	<?php
2
3	/**
4	* BaconQrCode
5	*
6	* @link http://github.com/Bacon/BaconQrCode For the canonical source repository
7	* @copyright 2013 Ben 'DASPRiD' Scholzen
8	* @license http://opensource.org/licenses/BSD-2-Clause Simplified BSD License
9	*/
10	namespace WP2FA_Vendor\BaconQrCode\Common;
11
12	/**
13	* Encapsulates a QR Code's format information, including the data mask used and error correction level.
14	*/
15	class FormatInformation
16	{
17	/**
18	* Mask for format information.
19	*/
20	private const FORMAT_INFO_MASK_QR = 0x5412;
21	/**
22	* Lookup table for decoding format information.
23	*
24	* See ISO 18004:2006, Annex C, Table C.1
25	*/
26	private const FORMAT_INFO_DECODE_LOOKUP = [[0x5412, 0x0], [0x5125, 0x1], [0x5e7c, 0x2], [0x5b4b, 0x3], [0x45f9, 0x4], [0x40ce, 0x5], [0x4f97, 0x6], [0x4aa0, 0x7], [0x77c4, 0x8], [0x72f3, 0x9], [0x7daa, 0xa], [0x789d, 0xb], [0x662f, 0xc], [0x6318, 0xd], [0x6c41, 0xe], [0x6976, 0xf], [0x1689, 0x10], [0x13be, 0x11], [0x1ce7, 0x12], [0x19d0, 0x13], [0x762, 0x14], [0x255, 0x15], [0xd0c, 0x16], [0x83b, 0x17], [0x355f, 0x18], [0x3068, 0x19], [0x3f31, 0x1a], [0x3a06, 0x1b], [0x24b4, 0x1c], [0x2183, 0x1d], [0x2eda, 0x1e], [0x2bed, 0x1f]];
27	/**
28	* Offset i holds the number of 1 bits in the binary representation of i.
29	*
30	* @var int[]
31	*/
32	private const BITS_SET_IN_HALF_BYTE = [0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4];
33	/**
34	* Error correction level.
35	*
36	* @var ErrorCorrectionLevel
37	*/
38	private $ecLevel;
39	/**
40	* Data mask.
41	*
42	* @var int
43	*/
44	private $dataMask;
45	protected function __construct(int $formatInfo)
46	{
47	$this->ecLevel = ErrorCorrectionLevel::forBits($formatInfo >> 3 & 0x3);
48	$this->dataMask = $formatInfo & 0x7;
49	}
50	/**
51	* Checks how many bits are different between two integers.
52	*/
53	public static function numBitsDiffering(int $a, int $b) : int
54	{
55	$a ^= $b;
56	return self::BITS_SET_IN_HALF_BYTE[$a & 0xf] + self::BITS_SET_IN_HALF_BYTE[BitUtils::unsignedRightShift($a, 4) & 0xf] + self::BITS_SET_IN_HALF_BYTE[BitUtils::unsignedRightShift($a, 8) & 0xf] + self::BITS_SET_IN_HALF_BYTE[BitUtils::unsignedRightShift($a, 12) & 0xf] + self::BITS_SET_IN_HALF_BYTE[BitUtils::unsignedRightShift($a, 16) & 0xf] + self::BITS_SET_IN_HALF_BYTE[BitUtils::unsignedRightShift($a, 20) & 0xf] + self::BITS_SET_IN_HALF_BYTE[BitUtils::unsignedRightShift($a, 24) & 0xf] + self::BITS_SET_IN_HALF_BYTE[BitUtils::unsignedRightShift($a, 28) & 0xf];
57	}
58	/**
59	* Decodes format information.
60	*/
61	public static function decodeFormatInformation(int $maskedFormatInfo1, int $maskedFormatInfo2) : ?self
62	{
63	$formatInfo = self::doDecodeFormatInformation($maskedFormatInfo1, $maskedFormatInfo2);
64	if (null !== $formatInfo) {
65	return $formatInfo;
66	}
67	// Should return null, but, some QR codes apparently do not mask this info. Try again by actually masking the
68	// pattern first.
69	return self::doDecodeFormatInformation($maskedFormatInfo1 ^ self::FORMAT_INFO_MASK_QR, $maskedFormatInfo2 ^ self::FORMAT_INFO_MASK_QR);
70	}
71	/**
72	* Internal method for decoding format information.
73	*/
74	private static function doDecodeFormatInformation(int $maskedFormatInfo1, int $maskedFormatInfo2) : ?self
75	{
76	$bestDifference = \PHP_INT_MAX;
77	$bestFormatInfo = 0;
78	foreach (self::FORMAT_INFO_DECODE_LOOKUP as $decodeInfo) {
79	$targetInfo = $decodeInfo[0];
80	if ($targetInfo === $maskedFormatInfo1 \|\| $targetInfo === $maskedFormatInfo2) {
81	// Found an exact match
82	return new self($decodeInfo[1]);
83	}
84	$bitsDifference = self::numBitsDiffering($maskedFormatInfo1, $targetInfo);
85	if ($bitsDifference < $bestDifference) {
86	$bestFormatInfo = $decodeInfo[1];
87	$bestDifference = $bitsDifference;
88	}
89	if ($maskedFormatInfo1 !== $maskedFormatInfo2) {
90	// Also try the other option
91	$bitsDifference = self::numBitsDiffering($maskedFormatInfo2, $targetInfo);
92	if ($bitsDifference < $bestDifference) {
93	$bestFormatInfo = $decodeInfo[1];
94	$bestDifference = $bitsDifference;
95	}
96	}
97	}
98	// Hamming distance of the 32 masked codes is 7, by construction, so <= 3 bits differing means we found a match.
99	if ($bestDifference <= 3) {
100	return new self($bestFormatInfo);
101	}
102	return null;
103	}
104	/**
105	* Returns the error correction level.
106	*/
107	public function getErrorCorrectionLevel() : ErrorCorrectionLevel
108	{
109	return $this->ecLevel;
110	}
111	/**
112	* Returns the data mask.
113	*/
114	public function getDataMask() : int
115	{
116	return $this->dataMask;
117	}
118	/**
119	* Hashes the code of the EC level.
120	*/
121	public function hashCode() : int
122	{
123	return $this->ecLevel->getBits() << 3 \| $this->dataMask;
124	}
125	/**
126	* Verifies if this instance equals another one.
127	*/
128	public function equals(self $other) : bool
129	{
130	return $this->ecLevel === $other->ecLevel && $this->dataMask === $other->dataMask;
131	}
132	}
133