:octocat: extract MaskPattern

src/Common/MaskPattern.php

@@ -0,0 +1,84 @@
+<?php
+/**
+ * Class MaskPattern
+ *
+ * @filesource   MaskPattern.php
+ * @created      19.01.2021
+ * @package      chillerlan\QRCode\Common
+ * @author       smiley <smiley@chillerlan.net>
+ * @copyright    2021 smiley
+ * @license      MIT
+ */
+
+namespace chillerlan\QRCode\Common;
+
+use chillerlan\QRCode\QRCodeException;
+use Closure;
+
+/**
+ *
+ */
+class MaskPattern{
+
+	public const PATTERN_000 = 0b000;
+	public const PATTERN_001 = 0b001;
+	public const PATTERN_010 = 0b010;
+	public const PATTERN_011 = 0b011;
+	public const PATTERN_100 = 0b100;
+	public const PATTERN_101 = 0b101;
+	public const PATTERN_110 = 0b110;
+	public const PATTERN_111 = 0b111;
+
+	public const PATTERNS = [
+		self::PATTERN_000,
+		self::PATTERN_001,
+		self::PATTERN_010,
+		self::PATTERN_011,
+		self::PATTERN_100,
+		self::PATTERN_101,
+		self::PATTERN_110,
+		self::PATTERN_111,
+	];
+
+	private int $maskPattern;
+
+	/**
+	 * MaskPattern constructor.
+	 *
+	 * ISO/IEC 18004:2000 Section 8.8.1
+	 *
+	 * @throws \chillerlan\QRCode\QRCodeException
+	 */
+	public function __construct(int $maskPattern){
+
+		if((0b111 & $maskPattern) !== $maskPattern){
+			throw new QRCodeException('invalid mask pattern'); // @codeCoverageIgnore
+		}
+
+		$this->maskPattern = $maskPattern;
+	}
+
+	public function getPattern():int{
+		return $this->maskPattern;
+	}
+
+	/**
+	 * ISO/IEC 18004:2000 Section 8.8.1
+	 *
+	 * Note that some versions of the QR code standard have had errors in the section about mask patterns.
+	 * The information below has been corrected. (https://www.thonky.com/qr-code-tutorial/mask-patterns)
+	 */
+	public function getMask():Closure{
+		return [
+			self::PATTERN_000 => fn($x, $y):int => ($x + $y) % 2,
+			self::PATTERN_001 => fn($x, $y):int => $y % 2,
+			self::PATTERN_010 => fn($x, $y):int => $x % 3,
+			self::PATTERN_011 => fn($x, $y):int => ($x + $y) % 3,
+			self::PATTERN_100 => fn($x, $y):int => ((int)($y / 2) + (int)($x / 3)) % 2,
+			self::PATTERN_101 => fn($x, $y):int => (($x * $y) % 2) + (($x * $y) % 3),
+			self::PATTERN_110 => fn($x, $y):int => ((($x * $y) % 2) + (($x * $y) % 3)) % 2,
+			self::PATTERN_111 => fn($x, $y):int => ((($x * $y) % 3) + (($x + $y) % 2)) % 2,
+		][$this->maskPattern];
+	}
+
+}