🛀 cleanup

src/Decoder/Binarizer.php

@@ -36,8 +36,8 @@ final class Binarizer{
 	// This class uses 5x5 blocks to compute local luminance, where each block is 8x8 pixels.
 	// So this is the smallest dimension in each axis we can accept.
 	private const BLOCK_SIZE_POWER  = 3;
-	private const BLOCK_SIZE        = 8; // ...0100...00
-	private const BLOCK_SIZE_MASK   = 7;   // ...0011...11
+	private const BLOCK_SIZE        = 8;  // ...0100...00
+	private const BLOCK_SIZE_MASK   = 7;  // ...0011...11
 	private const MINIMUM_DIMENSION = 40;
 	private const MIN_DYNAMIC_RANGE = 24;
 

src/Decoder/BitMatrix.php

@@ -13,7 +13,6 @@ namespace chillerlan\QRCode\Decoder;
 
 use chillerlan\QRCode\Common\{MaskPattern, Version};
 use InvalidArgumentException;
-use function chillerlan\QRCode\Common\uRShift;
 use function array_fill, count;
 
 final class BitMatrix{
@@ -110,7 +109,7 @@ final class BitMatrix{
 
 		$this->bits[$offset] ??= 0;
 
-		return (uRShift($this->bits[$offset], ($x & 0x1f)) & 1) !== 0;
+		return (BitMatrixParser::uRShift($this->bits[$offset], ($x & 0x1f)) & 1) !== 0;
 	}
 
 	/**

src/Decoder/BitMatrixParser.php

@@ -13,8 +13,7 @@ namespace chillerlan\QRCode\Decoder;
 
 use RuntimeException;
 use chillerlan\QRCode\Common\{Version, FormatInformation};
-use function chillerlan\QRCode\Common\numBitsDiffering;
-use const PHP_INT_MAX;
+use const PHP_INT_MAX, PHP_INT_SIZE;
 
 /**
  * @author Sean Owen
@@ -219,7 +218,7 @@ final class BitMatrixParser{
 				return new FormatInformation($maskedBits);
 			}
 
-			$bitsDifference = numBitsDiffering($maskedFormatInfo1, $dataBits);
+			$bitsDifference = self::numBitsDiffering($maskedFormatInfo1, $dataBits);
 
 			if($bitsDifference < $bestDifference){
 				$bestFormatInfo = $maskedBits;
@@ -228,7 +227,7 @@ final class BitMatrixParser{
 
 			if($maskedFormatInfo1 !== $maskedFormatInfo2){
 				// also try the other option
-				$bitsDifference = numBitsDiffering($maskedFormatInfo2, $dataBits);
+				$bitsDifference = self::numBitsDiffering($maskedFormatInfo2, $dataBits);
 
 				if($bitsDifference < $bestDifference){
 					$bestFormatInfo = $maskedBits;
@@ -319,7 +318,7 @@ final class BitMatrixParser{
 			// Otherwise see if this is the closest to a real version info bit string
 			// we have seen so far
 			/** @phan-suppress-next-line PhanTypeMismatchArgumentNullable ($targetVersionPattern is never null here) */
-			$bitsDifference = numBitsDiffering($versionBits, $targetVersionPattern);
+			$bitsDifference = self::numBitsDiffering($versionBits, $targetVersionPattern);
 
 			if($bitsDifference < $bestDifference){
 				$bestVersion    = $i;
@@ -336,4 +335,28 @@ final class BitMatrixParser{
 		return null;
 	}
 
+	public static function uRShift(int $a, int $b):int{
+
+		if($b === 0){
+			return $a;
+		}
+
+		return ($a >> $b) & ~((1 << (8 * PHP_INT_SIZE - 1)) >> ($b - 1));
+	}
+
+	private static function numBitsDiffering(int $a, int $b):int{
+		// a now has a 1 bit exactly where its bit differs with b's
+		$a ^= $b;
+		// Offset i holds the number of 1 bits in the binary representation of i
+		$BITS_SET_IN_HALF_BYTE = [0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4];
+		// Count bits set quickly with a series of lookups:
+		$count = 0;
+
+		for($i = 0; $i < 32; $i += 4){
+			$count += $BITS_SET_IN_HALF_BYTE[self::uRShift($a, $i) & 0x0F];
+		}
+
+		return $count;
+	}
+
 }

src/Decoder/LuminanceSource.php

@@ -12,7 +12,7 @@
 namespace chillerlan\QRCode\Decoder;
 
 use InvalidArgumentException;
-use function chillerlan\QRCode\Common\arraycopy;
+use function array_slice, array_splice;
 
 /**
  * The purpose of this class hierarchy is to abstract different bitmap implementations across
@@ -82,7 +82,11 @@ abstract class LuminanceSource{
 			throw new InvalidArgumentException('Requested row is outside the image: '.$y);
 		}
 
-		return arraycopy($this->luminances, $y * $this->width, [], 0, $this->width);
+		$arr = [];
+
+		array_splice($arr, 0, $this->width, array_slice($this->luminances, $y * $this->width, $this->width));
+
+		return $arr;
 	}
 
 	/**