mirror of
https://github.com/chillerlan/php-qrcode.git
synced 2026-08-24 14:57:53 +00:00
🚿 include BitMatrixParser in BitMatrix, cleanup
This commit is contained in:
codemasher
+363
-19
@@ -11,18 +11,22 @@
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namespace chillerlan\QRCode\Decoder;
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use chillerlan\QRCode\Common\{MaskPattern, Version};
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use InvalidArgumentException;
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use chillerlan\QRCode\Common\{FormatInformation, Version};
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use InvalidArgumentException, RuntimeException;
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use function array_fill, count;
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use const PHP_INT_MAX, PHP_INT_SIZE;
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/**
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*
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*/
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final class BitMatrix{
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private int $dimension;
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private int $rowSize;
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private array $bits;
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private int $dimension;
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private int $rowSize;
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private array $bits;
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private ?Version $version = null;
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private ?FormatInformation $formatInfo = null;
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private bool $mirror = false;
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/**
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*
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@@ -39,11 +43,13 @@ final class BitMatrix{
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* @param int $x ; The horizontal component (i.e. which column)
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* @param int $y ; The vertical component (i.e. which row)
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*/
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public function set(int $x, int $y):void{
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public function set(int $x, int $y):self{
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$offset = (int)($y * $this->rowSize + ($x / 0x20));
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$this->bits[$offset] ??= 0;
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$this->bits[$offset] |= ($this->bits[$offset] |= 1 << ($x & 0x1f));
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return $this;
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}
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/**
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@@ -52,10 +58,12 @@ final class BitMatrix{
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* @param int $x ; The horizontal component (i.e. which column)
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* @param int $y ; The vertical component (i.e. which row)
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*/
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public function flip(int $x, int $y):void{
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public function flip(int $x, int $y):self{
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$offset = $y * $this->rowSize + (int)($x / 0x20);
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$this->bits[$offset] = ($this->bits[$offset] ^ (1 << ($x & 0x1f)));
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return $this;
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}
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/**
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@@ -68,7 +76,7 @@ final class BitMatrix{
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*
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* @throws \InvalidArgumentException
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*/
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public function setRegion(int $left, int $top, int $width, int $height):void{
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public function setRegion(int $left, int $top, int $width, int $height):self{
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if($top < 0 || $left < 0){
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throw new InvalidArgumentException('Left and top must be nonnegative');
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@@ -93,6 +101,8 @@ final class BitMatrix{
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$this->bits[$xOffset] = ($this->bits[$xOffset] |= 1 << ($x & 0x1f));
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}
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}
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return $this;
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}
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/**
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@@ -102,6 +112,20 @@ final class BitMatrix{
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return $this->dimension;
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}
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/**
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*
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*/
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public function getFormatInfo():?FormatInformation{
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return $this->formatInfo;
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}
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/**
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*
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*/
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public function getVersion():?Version{
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return $this->version;
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}
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/**
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* <p>Gets the requested bit, where true means black.</p>
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*
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@@ -115,15 +139,14 @@ final class BitMatrix{
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$this->bits[$offset] ??= 0;
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return (BitMatrixParser::uRShift($this->bits[$offset], ($x & 0x1f)) & 1) !== 0;
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return ($this->uRShift($this->bits[$offset], ($x & 0x1f)) & 1) !== 0;
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}
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/**
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* See ISO 18004:2006 Annex E
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*/
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public function buildFunctionPattern(Version $version):BitMatrix{
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$dimension = $version->getDimension();
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// @todo
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private function buildFunctionPattern():self{
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$dimension = $this->version->getDimension();
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$bitMatrix = new self($dimension);
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// Top left finder pattern + separator + format
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@@ -134,7 +157,7 @@ final class BitMatrix{
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$bitMatrix->setRegion(0, $dimension - 8, 9, 8);
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// Alignment patterns
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$apc = $version->getAlignmentPattern();
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$apc = $this->version->getAlignmentPattern();
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$max = count($apc);
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for($x = 0; $x < $max; $x++){
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@@ -155,7 +178,7 @@ final class BitMatrix{
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// Horizontal timing pattern
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$bitMatrix->setRegion(9, 6, $dimension - 17, 1);
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if($version->getVersionNumber() > 6){
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if($this->version->getVersionNumber() > 6){
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// Version info, top right
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$bitMatrix->setRegion($dimension - 11, 0, 3, 6);
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// Version info, bottom left
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@@ -168,7 +191,7 @@ final class BitMatrix{
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/**
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* Mirror the bit matrix in order to attempt a second reading.
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*/
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public function mirror():void{
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public function mirror():self{
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for($x = 0; $x < $this->dimension; $x++){
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for($y = $x + 1; $y < $this->dimension; $y++){
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@@ -179,17 +202,18 @@ final class BitMatrix{
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}
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}
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return $this;
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}
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/**
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* Implementations of this method reverse the data masking process applied to a QR Code and
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* make its bits ready to read.
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*/
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public function unmask(int $dimension, MaskPattern $maskPattern):void{
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$mask = $maskPattern->getMask();
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private function unmask():void{
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$mask = $this->formatInfo->getMaskPattern()->getMask();
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for($y = 0; $y < $dimension; $y++){
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for($x = 0; $x < $dimension; $x++){
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for($y = 0; $y < $this->dimension; $y++){
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for($x = 0; $x < $this->dimension; $x++){
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if($mask($x, $y)){
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$this->flip($x, $y);
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}
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@@ -198,4 +222,324 @@ final class BitMatrix{
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}
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/**
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* Prepare the parser for a mirrored operation.
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* This flag has effect only on the {@link #readFormatInformation()} and the
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* {@link #readVersion()}. Before proceeding with {@link #readCodewords()} the
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* {@link #mirror()} method should be called.
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*
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* @param bool $mirror Whether to read version and format information mirrored.
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*/
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public function setMirror(bool $mirror):self{
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$this->version = null;
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$this->formatInfo = null;
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$this->mirror = $mirror;
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return $this;
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}
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/**
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*
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*/
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private function copyBit(int $i, int $j, int $versionBits):int{
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$bit = $this->mirror
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? $this->get($j, $i)
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: $this->get($i, $j);
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return $bit ? ($versionBits << 1) | 0x1 : $versionBits << 1;
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}
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/**
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* <p>Reads the bits in the {@link BitMatrix} representing the finder pattern in the
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* correct order in order to reconstruct the codewords bytes contained within the
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* QR Code.</p>
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*
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* @return array bytes encoded within the QR Code
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* @throws \RuntimeException if the exact number of bytes expected is not read
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*/
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public function readCodewords():array{
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$this->formatInfo = $this->readFormatInformation();
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$this->version = $this->readVersion();
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// Get the data mask for the format used in this QR Code. This will exclude
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// some bits from reading as we wind through the bit matrix.
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$this->unmask();
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$functionPattern = $this->buildFunctionPattern();
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$readingUp = true;
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$result = [];
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$resultOffset = 0;
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$currentByte = 0;
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$bitsRead = 0;
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// Read columns in pairs, from right to left
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for($j = $this->dimension - 1; $j > 0; $j -= 2){
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if($j === 6){
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// Skip whole column with vertical alignment pattern;
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// saves time and makes the other code proceed more cleanly
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$j--;
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}
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// Read alternatingly from bottom to top then top to bottom
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for($count = 0; $count < $this->dimension; $count++){
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$i = $readingUp ? $this->dimension - 1 - $count : $count;
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for($col = 0; $col < 2; $col++){
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// Ignore bits covered by the function pattern
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if(!$functionPattern->get($j - $col, $i)){
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// Read a bit
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$bitsRead++;
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$currentByte <<= 1;
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if($this->get($j - $col, $i)){
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$currentByte |= 1;
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}
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// If we've made a whole byte, save it off
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if($bitsRead === 8){
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$result[$resultOffset++] = $currentByte; //(byte)
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$bitsRead = 0;
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$currentByte = 0;
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}
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}
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}
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}
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$readingUp = !$readingUp; // switch directions
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}
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if($resultOffset !== $this->version->getTotalCodewords()){
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throw new RuntimeException('offset differs from total codewords for version');
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}
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return $result;
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}
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/**
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* <p>Reads format information from one of its two locations within the QR Code.</p>
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*
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* @return \chillerlan\QRCode\Common\FormatInformation encapsulating the QR Code's format info
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* @throws \RuntimeException if both format information locations cannot be parsed as
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* the valid encoding of format information
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*/
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private function readFormatInformation():FormatInformation{
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if($this->formatInfo !== null){
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return $this->formatInfo;
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}
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// Read top-left format info bits
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$formatInfoBits1 = 0;
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for($i = 0; $i < 6; $i++){
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$formatInfoBits1 = $this->copyBit($i, 8, $formatInfoBits1);
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}
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// .. and skip a bit in the timing pattern ...
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$formatInfoBits1 = $this->copyBit(7, 8, $formatInfoBits1);
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$formatInfoBits1 = $this->copyBit(8, 8, $formatInfoBits1);
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$formatInfoBits1 = $this->copyBit(8, 7, $formatInfoBits1);
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// .. and skip a bit in the timing pattern ...
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for($j = 5; $j >= 0; $j--){
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$formatInfoBits1 = $this->copyBit(8, $j, $formatInfoBits1);
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}
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// Read the top-right/bottom-left pattern too
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$formatInfoBits2 = 0;
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$jMin = $this->dimension - 7;
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for($j = $this->dimension - 1; $j >= $jMin; $j--){
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$formatInfoBits2 = $this->copyBit(8, $j, $formatInfoBits2);
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}
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for($i = $this->dimension - 8; $i < $this->dimension; $i++){
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$formatInfoBits2 = $this->copyBit($i, 8, $formatInfoBits2);
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}
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$this->formatInfo = $this->doDecodeFormatInformation($formatInfoBits1, $formatInfoBits2);
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if($this->formatInfo !== null){
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return $this->formatInfo;
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}
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// Should return null, but, some QR codes apparently do not mask this info.
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// Try again by actually masking the pattern first.
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$this->formatInfo = $this->doDecodeFormatInformation(
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$formatInfoBits1 ^ FormatInformation::FORMAT_INFO_MASK_QR,
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$formatInfoBits2 ^ FormatInformation::FORMAT_INFO_MASK_QR
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);
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if($this->formatInfo !== null){
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return $this->formatInfo;
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}
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throw new RuntimeException('failed to read format info');
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}
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/**
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* @param int $maskedFormatInfo1 format info indicator, with mask still applied
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* @param int $maskedFormatInfo2 second copy of same info; both are checked at the same time
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* to establish best match
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*
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* @return \chillerlan\QRCode\Common\FormatInformation|null information about the format it specifies, or null
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* if doesn't seem to match any known pattern
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*/
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private function doDecodeFormatInformation(int $maskedFormatInfo1, int $maskedFormatInfo2):?FormatInformation{
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// Find the int in FORMAT_INFO_DECODE_LOOKUP with fewest bits differing
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$bestDifference = PHP_INT_MAX;
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$bestFormatInfo = 0;
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foreach(FormatInformation::DECODE_LOOKUP as $decodeInfo){
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[$maskedBits, $dataBits] = $decodeInfo;
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if($maskedFormatInfo1 === $dataBits || $maskedFormatInfo2 === $dataBits){
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// Found an exact match
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return new FormatInformation($maskedBits);
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}
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$bitsDifference = $this->numBitsDiffering($maskedFormatInfo1, $dataBits);
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if($bitsDifference < $bestDifference){
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$bestFormatInfo = $maskedBits;
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$bestDifference = $bitsDifference;
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}
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if($maskedFormatInfo1 !== $maskedFormatInfo2){
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// also try the other option
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$bitsDifference = $this->numBitsDiffering($maskedFormatInfo2, $dataBits);
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if($bitsDifference < $bestDifference){
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$bestFormatInfo = $maskedBits;
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$bestDifference = $bitsDifference;
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}
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}
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}
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// Hamming distance of the 32 masked codes is 7, by construction, so <= 3 bits differing means we found a match
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if($bestDifference <= 3){
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return new FormatInformation($bestFormatInfo);
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}
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return null;
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}
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/**
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* <p>Reads version information from one of its two locations within the QR Code.</p>
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*
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* @return \chillerlan\QRCode\Common\Version encapsulating the QR Code's version
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* @throws \RuntimeException if both version information locations cannot be parsed as
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* the valid encoding of version information
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*/
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private function readVersion():Version{
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if($this->version !== null){
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return $this->version;
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}
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$provisionalVersion = ($this->dimension - 17) / 4;
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if($provisionalVersion <= 6){
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return new Version($provisionalVersion);
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}
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// Read top-right version info: 3 wide by 6 tall
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$versionBits = 0;
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$ijMin = $this->dimension - 11;
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for($j = 5; $j >= 0; $j--){
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for($i = $this->dimension - 9; $i >= $ijMin; $i--){
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$versionBits = $this->copyBit($i, $j, $versionBits);
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}
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}
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$this->version = $this->decodeVersionInformation($versionBits);
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if($this->version !== null && $this->version->getDimension() === $this->dimension){
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return $this->version;
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}
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// Hmm, failed. Try bottom left: 6 wide by 3 tall
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$versionBits = 0;
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for($i = 5; $i >= 0; $i--){
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for($j = $this->dimension - 9; $j >= $ijMin; $j--){
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$versionBits = $this->copyBit($i, $j, $versionBits);
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}
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}
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$this->version = $this->decodeVersionInformation($versionBits);
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if($this->version !== null && $this->version->getDimension() === $this->dimension){
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return $this->version;
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}
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throw new RuntimeException('failed to read version');
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}
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/**
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* @param int $versionBits
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*
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* @return \chillerlan\QRCode\Common\Version|null
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*/
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private function decodeVersionInformation(int $versionBits):?Version{
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$bestDifference = PHP_INT_MAX;
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$bestVersion = 0;
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for($i = 7; $i <= 40; $i++){
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$targetVersion = new Version($i);
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$targetVersionPattern = $targetVersion->getVersionPattern();
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// Do the version info bits match exactly? done.
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if($targetVersionPattern === $versionBits){
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return $targetVersion;
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}
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// Otherwise see if this is the closest to a real version info bit string
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// we have seen so far
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/** @phan-suppress-next-line PhanTypeMismatchArgumentNullable ($targetVersionPattern is never null here) */
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$bitsDifference = $this->numBitsDiffering($versionBits, $targetVersionPattern);
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if($bitsDifference < $bestDifference){
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$bestVersion = $i;
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$bestDifference = $bitsDifference;
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}
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}
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// We can tolerate up to 3 bits of error since no two version info codewords will
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// differ in less than 8 bits.
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if($bestDifference <= 3){
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return new Version($bestVersion);
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}
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// If we didn't find a close enough match, fail
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return null;
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}
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/**
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*
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*/
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private function uRShift(int $a, int $b):int{
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if($b === 0){
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return $a;
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}
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return ($a >> $b) & ~((1 << (8 * PHP_INT_SIZE - 1)) >> ($b - 1));
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}
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/**
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*
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*/
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private function numBitsDiffering(int $a, int $b):int{
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// a now has a 1 bit exactly where its bit differs with b's
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$a ^= $b;
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// Offset i holds the number of 1 bits in the binary representation of i
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$BITS_SET_IN_HALF_BYTE = [0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4];
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// Count bits set quickly with a series of lookups:
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$count = 0;
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for($i = 0; $i < 32; $i += 4){
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$count += $BITS_SET_IN_HALF_BYTE[$this->uRShift($a, $i) & 0x0F];
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}
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return $count;
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}
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}
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