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<?php
declare(strict_types = 1);
namespace BaconQrCode\Encoder;
use BaconQrCode\Common\BitArray;
use BaconQrCode\Common\CharacterSetEci;
use BaconQrCode\Common\ErrorCorrectionLevel;
use BaconQrCode\Common\Mode;
use BaconQrCode\Common\ReedSolomonCodec;
use BaconQrCode\Common\Version;
use BaconQrCode\Exception\WriterException;
use SplFixedArray;
/**
* Encoder.
*/
final class Encoder
{
/**
* Default byte encoding.
*/
public const DEFAULT_BYTE_MODE_ECODING = 'ISO-8859-1';
/**
* The original table is defined in the table 5 of JISX0510:2004 (p.19).
*/
private const ALPHANUMERIC_TABLE = [
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0x00-0x0f
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, // 0x10-0x1f
36, -1, -1, -1, 37, 38, -1, -1, -1, -1, 39, 40, -1, 41, 42, 43, // 0x20-0x2f
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 44, -1, -1, -1, -1, -1, // 0x30-0x3f
-1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 0x40-0x4f
25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, -1, // 0x50-0x5f
];
/**
* Codec cache.
*
* @var array
*/
private static $codecs = [];
/**
* Encodes "content" with the error correction level "ecLevel".
*/
public static function encode(
string $content,
ErrorCorrectionLevel $ecLevel,
string $encoding = self::DEFAULT_BYTE_MODE_ECODING,
?Version $forcedVersion = null
) : QrCode {
// Pick an encoding mode appropriate for the content. Note that this
// will not attempt to use multiple modes / segments even if that were
// more efficient. Would be nice.
$mode = self::chooseMode($content, $encoding);
// This will store the header information, like mode and length, as well
// as "header" segments like an ECI segment.
$headerBits = new BitArray();
// Append ECI segment if applicable
if (Mode::BYTE() === $mode && self::DEFAULT_BYTE_MODE_ECODING !== $encoding) {
$eci = CharacterSetEci::getCharacterSetEciByName($encoding);
if (null !== $eci) {
self::appendEci($eci, $headerBits);
}
}
// (With ECI in place,) Write the mode marker
self::appendModeInfo($mode, $headerBits);
// Collect data within the main segment, separately, to count its size
// if needed. Don't add it to main payload yet.
$dataBits = new BitArray();
self::appendBytes($content, $mode, $dataBits, $encoding);
// Hard part: need to know version to know how many bits length takes.
// But need to know how many bits it takes to know version. First we
// take a guess at version by assuming version will be the minimum, 1:
$provisionalBitsNeeded = $headerBits->getSize()
+ $mode->getCharacterCountBits(Version::getVersionForNumber(1))
+ $dataBits->getSize();
$provisionalVersion = self::chooseVersion($provisionalBitsNeeded, $ecLevel);
// Use that guess to calculate the right version. I am still not sure
// this works in 100% of cases.
$bitsNeeded = $headerBits->getSize()
+ $mode->getCharacterCountBits($provisionalVersion)
+ $dataBits->getSize();
$version = self::chooseVersion($bitsNeeded, $ecLevel);
if (null !== $forcedVersion) {
// Forced version check
if ($version->getVersionNumber() <= $forcedVersion->getVersionNumber()) {
// Calculated minimum version is same or equal as forced version
$version = $forcedVersion;
} else {
throw new WriterException(
'Invalid version! Calculated version: '
. $version->getVersionNumber()
. ', requested version: '
. $forcedVersion->getVersionNumber()
);
}
}
$headerAndDataBits = new BitArray();
$headerAndDataBits->appendBitArray($headerBits);
// Find "length" of main segment and write it.
$numLetters = (Mode::BYTE() === $mode ? $dataBits->getSizeInBytes() : strlen($content));
self::appendLengthInfo($numLetters, $version, $mode, $headerAndDataBits);
// Put data together into the overall payload.
$headerAndDataBits->appendBitArray($dataBits);
$ecBlocks = $version->getEcBlocksForLevel($ecLevel);
$numDataBytes = $version->getTotalCodewords() - $ecBlocks->getTotalEcCodewords();
// Terminate the bits properly.
self::terminateBits($numDataBytes, $headerAndDataBits);
// Interleave data bits with error correction code.
$finalBits = self::interleaveWithEcBytes(
$headerAndDataBits,
$version->getTotalCodewords(),
$numDataBytes,
$ecBlocks->getNumBlocks()
);
// Choose the mask pattern.
$dimension = $version->getDimensionForVersion();
$matrix = new ByteMatrix($dimension, $dimension);
$maskPattern = self::chooseMaskPattern($finalBits, $ecLevel, $version, $matrix);
// Build the matrix.
MatrixUtil::buildMatrix($finalBits, $ecLevel, $version, $maskPattern, $matrix);
return new QrCode($mode, $ecLevel, $version, $maskPattern, $matrix);
}
/**
* Gets the alphanumeric code for a byte.
*/
private static function getAlphanumericCode(int $code) : int
{
if (isset(self::ALPHANUMERIC_TABLE[$code])) {
return self::ALPHANUMERIC_TABLE[$code];
}
return -1;
}
/**
* Chooses the best mode for a given content.
*/
private static function chooseMode(string $content, string $encoding = null) : Mode
{
if (null !== $encoding && 0 === strcasecmp($encoding, 'SHIFT-JIS')) {
return self::isOnlyDoubleByteKanji($content) ? Mode::KANJI() : Mode::BYTE();
}
$hasNumeric = false;
$hasAlphanumeric = false;
$contentLength = strlen($content);
for ($i = 0; $i < $contentLength; ++$i) {
$char = $content[$i];
if (ctype_digit($char)) {
$hasNumeric = true;
} elseif (-1 !== self::getAlphanumericCode(ord($char))) {
$hasAlphanumeric = true;
} else {
return Mode::BYTE();
}
}
if ($hasAlphanumeric) {
return Mode::ALPHANUMERIC();
} elseif ($hasNumeric) {
return Mode::NUMERIC();
}
return Mode::BYTE();
}
/**
* Calculates the mask penalty for a matrix.
*/
private static function calculateMaskPenalty(ByteMatrix $matrix) : int
{
return (
MaskUtil::applyMaskPenaltyRule1($matrix)
+ MaskUtil::applyMaskPenaltyRule2($matrix)
+ MaskUtil::applyMaskPenaltyRule3($matrix)
+ MaskUtil::applyMaskPenaltyRule4($matrix)
);
}
/**
* Checks if content only consists of double-byte kanji characters.
*/
private static function isOnlyDoubleByteKanji(string $content) : bool
{
$bytes = @iconv('utf-8', 'SHIFT-JIS', $content);
if (false === $bytes) {
return false;
}
$length = strlen($bytes);
if (0 !== $length % 2) {
return false;
}
for ($i = 0; $i < $length; $i += 2) {
$byte = $bytes[$i] & 0xff;
if (($byte < 0x81 || $byte > 0x9f) && $byte < 0xe0 || $byte > 0xeb) {
return false;
}
}
return true;
}
/**
* Chooses the best mask pattern for a matrix.
*/
private static function chooseMaskPattern(
BitArray $bits,
ErrorCorrectionLevel $ecLevel,
Version $version,
ByteMatrix $matrix
) : int {
$minPenalty = PHP_INT_MAX;
$bestMaskPattern = -1;
for ($maskPattern = 0; $maskPattern < QrCode::NUM_MASK_PATTERNS; ++$maskPattern) {
MatrixUtil::buildMatrix($bits, $ecLevel, $version, $maskPattern, $matrix);
$penalty = self::calculateMaskPenalty($matrix);
if ($penalty < $minPenalty) {
$minPenalty = $penalty;
$bestMaskPattern = $maskPattern;
}
}
return $bestMaskPattern;
}
/**
* Chooses the best version for the input.
*
* @throws WriterException if data is too big
*/
private static function chooseVersion(int $numInputBits, ErrorCorrectionLevel $ecLevel) : Version
{
for ($versionNum = 1; $versionNum <= 40; ++$versionNum) {
$version = Version::getVersionForNumber($versionNum);
$numBytes = $version->getTotalCodewords();
$ecBlocks = $version->getEcBlocksForLevel($ecLevel);
$numEcBytes = $ecBlocks->getTotalEcCodewords();
$numDataBytes = $numBytes - $numEcBytes;
$totalInputBytes = intdiv($numInputBits + 8, 8);
if ($numDataBytes >= $totalInputBytes) {
return $version;
}
}
throw new WriterException('Data too big');
}
/**
* Terminates the bits in a bit array.
*
* @throws WriterException if data bits cannot fit in the QR code
* @throws WriterException if bits size does not equal the capacity
*/
private static function terminateBits(int $numDataBytes, BitArray $bits) : void
{
$capacity = $numDataBytes << 3;
if ($bits->getSize() > $capacity) {
throw new WriterException('Data bits cannot fit in the QR code');
}
for ($i = 0; $i < 4 && $bits->getSize() < $capacity; ++$i) {
$bits->appendBit(false);
}
$numBitsInLastByte = $bits->getSize() & 0x7;
if ($numBitsInLastByte > 0) {
for ($i = $numBitsInLastByte; $i < 8; ++$i) {
$bits->appendBit(false);
}
}
$numPaddingBytes = $numDataBytes - $bits->getSizeInBytes();
for ($i = 0; $i < $numPaddingBytes; ++$i) {
$bits->appendBits(0 === ($i & 0x1) ? 0xec : 0x11, 8);
}
if ($bits->getSize() !== $capacity) {
throw new WriterException('Bits size does not equal capacity');
}
}
/**
* Gets number of data- and EC bytes for a block ID.
*
* @return int[]
* @throws WriterException if block ID is too large
* @throws WriterException if EC bytes mismatch
* @throws WriterException if RS blocks mismatch
* @throws WriterException if total bytes mismatch
*/
private static function getNumDataBytesAndNumEcBytesForBlockId(
int $numTotalBytes,
int $numDataBytes,
int $numRsBlocks,
int $blockId
) : array {
if ($blockId >= $numRsBlocks) {
throw new WriterException('Block ID too large');
}
$numRsBlocksInGroup2 = $numTotalBytes % $numRsBlocks;
$numRsBlocksInGroup1 = $numRsBlocks - $numRsBlocksInGroup2;
$numTotalBytesInGroup1 = intdiv($numTotalBytes, $numRsBlocks);
$numTotalBytesInGroup2 = $numTotalBytesInGroup1 + 1;
$numDataBytesInGroup1 = intdiv($numDataBytes, $numRsBlocks);
$numDataBytesInGroup2 = $numDataBytesInGroup1 + 1;
$numEcBytesInGroup1 = $numTotalBytesInGroup1 - $numDataBytesInGroup1;
$numEcBytesInGroup2 = $numTotalBytesInGroup2 - $numDataBytesInGroup2;
if ($numEcBytesInGroup1 !== $numEcBytesInGroup2) {
throw new WriterException('EC bytes mismatch');
}
if ($numRsBlocks !== $numRsBlocksInGroup1 + $numRsBlocksInGroup2) {
throw new WriterException('RS blocks mismatch');
}
if ($numTotalBytes !==
(($numDataBytesInGroup1 + $numEcBytesInGroup1) * $numRsBlocksInGroup1)
+ (($numDataBytesInGroup2 + $numEcBytesInGroup2) * $numRsBlocksInGroup2)
) {
throw new WriterException('Total bytes mismatch');
}
if ($blockId < $numRsBlocksInGroup1) {
return [$numDataBytesInGroup1, $numEcBytesInGroup1];
} else {
return [$numDataBytesInGroup2, $numEcBytesInGroup2];
}
}
/**
* Interleaves data with EC bytes.
*
* @throws WriterException if number of bits and data bytes does not match
* @throws WriterException if data bytes does not match offset
* @throws WriterException if an interleaving error occurs
*/
private static function interleaveWithEcBytes(
BitArray $bits,
int $numTotalBytes,
int $numDataBytes,
int $numRsBlocks
) : BitArray {
if ($bits->getSizeInBytes() !== $numDataBytes) {
throw new WriterException('Number of bits and data bytes does not match');
}
$dataBytesOffset = 0;
$maxNumDataBytes = 0;
$maxNumEcBytes = 0;
$blocks = new SplFixedArray($numRsBlocks);
for ($i = 0; $i < $numRsBlocks; ++$i) {
list($numDataBytesInBlock, $numEcBytesInBlock) = self::getNumDataBytesAndNumEcBytesForBlockId(
$numTotalBytes,
$numDataBytes,
$numRsBlocks,
$i
);
$size = $numDataBytesInBlock;
$dataBytes = $bits->toBytes(8 * $dataBytesOffset, $size);
$ecBytes = self::generateEcBytes($dataBytes, $numEcBytesInBlock);
$blocks[$i] = new BlockPair($dataBytes, $ecBytes);
$maxNumDataBytes = max($maxNumDataBytes, $size);
$maxNumEcBytes = max($maxNumEcBytes, count($ecBytes));
$dataBytesOffset += $numDataBytesInBlock;
}
if ($numDataBytes !== $dataBytesOffset) {
throw new WriterException('Data bytes does not match offset');
}
$result = new BitArray();
for ($i = 0; $i < $maxNumDataBytes; ++$i) {
foreach ($blocks as $block) {
$dataBytes = $block->getDataBytes();
if ($i < count($dataBytes)) {
$result->appendBits($dataBytes[$i], 8);
}
}
}
for ($i = 0; $i < $maxNumEcBytes; ++$i) {
foreach ($blocks as $block) {
$ecBytes = $block->getErrorCorrectionBytes();
if ($i < count($ecBytes)) {
$result->appendBits($ecBytes[$i], 8);
}
}
}
if ($numTotalBytes !== $result->getSizeInBytes()) {
throw new WriterException(
'Interleaving error: ' . $numTotalBytes . ' and ' . $result->getSizeInBytes() . ' differ'
);
}
return $result;
}
/**
* Generates EC bytes for given data.
*
* @param SplFixedArray<int> $dataBytes
* @return SplFixedArray<int>
*/
private static function generateEcBytes(SplFixedArray $dataBytes, int $numEcBytesInBlock) : SplFixedArray
{
$numDataBytes = count($dataBytes);
$toEncode = new SplFixedArray($numDataBytes + $numEcBytesInBlock);
for ($i = 0; $i < $numDataBytes; $i++) {
$toEncode[$i] = $dataBytes[$i] & 0xff;
}
$ecBytes = new SplFixedArray($numEcBytesInBlock);
$codec = self::getCodec($numDataBytes, $numEcBytesInBlock);
$codec->encode($toEncode, $ecBytes);
return $ecBytes;
}
/**
* Gets an RS codec and caches it.
*/
private static function getCodec(int $numDataBytes, int $numEcBytesInBlock) : ReedSolomonCodec
{
$cacheId = $numDataBytes . '-' . $numEcBytesInBlock;
if (isset(self::$codecs[$cacheId])) {
return self::$codecs[$cacheId];
}
return self::$codecs[$cacheId] = new ReedSolomonCodec(
8,
0x11d,
0,
1,
$numEcBytesInBlock,
255 - $numDataBytes - $numEcBytesInBlock
);
}
/**
* Appends mode information to a bit array.
*/
private static function appendModeInfo(Mode $mode, BitArray $bits) : void
{
$bits->appendBits($mode->getBits(), 4);
}
/**
* Appends length information to a bit array.
*
* @throws WriterException if num letters is bigger than expected
*/
private static function appendLengthInfo(int $numLetters, Version $version, Mode $mode, BitArray $bits) : void
{
$numBits = $mode->getCharacterCountBits($version);
if ($numLetters >= (1 << $numBits)) {
throw new WriterException($numLetters . ' is bigger than ' . ((1 << $numBits) - 1));
}
$bits->appendBits($numLetters, $numBits);
}
/**
* Appends bytes to a bit array in a specific mode.
*
* @throws WriterException if an invalid mode was supplied
*/
private static function appendBytes(string $content, Mode $mode, BitArray $bits, string $encoding) : void
{
switch ($mode) {
case Mode::NUMERIC():
self::appendNumericBytes($content, $bits);
break;
case Mode::ALPHANUMERIC():
self::appendAlphanumericBytes($content, $bits);
break;
case Mode::BYTE():
self::append8BitBytes($content, $bits, $encoding);
break;
case Mode::KANJI():
self::appendKanjiBytes($content, $bits);
break;
default:
throw new WriterException('Invalid mode: ' . $mode);
}
}
/**
* Appends numeric bytes to a bit array.
*/
private static function appendNumericBytes(string $content, BitArray $bits) : void
{
$length = strlen($content);
$i = 0;
while ($i < $length) {
$num1 = (int) $content[$i];
if ($i + 2 < $length) {
// Encode three numeric letters in ten bits.
$num2 = (int) $content[$i + 1];
$num3 = (int) $content[$i + 2];
$bits->appendBits($num1 * 100 + $num2 * 10 + $num3, 10);
$i += 3;
} elseif ($i + 1 < $length) {
// Encode two numeric letters in seven bits.
$num2 = (int) $content[$i + 1];
$bits->appendBits($num1 * 10 + $num2, 7);
$i += 2;
} else {
// Encode one numeric letter in four bits.
$bits->appendBits($num1, 4);
++$i;
}
}
}
/**
* Appends alpha-numeric bytes to a bit array.
*
* @throws WriterException if an invalid alphanumeric code was found
*/
private static function appendAlphanumericBytes(string $content, BitArray $bits) : void
{
$length = strlen($content);
$i = 0;
while ($i < $length) {
$code1 = self::getAlphanumericCode(ord($content[$i]));
if (-1 === $code1) {
throw new WriterException('Invalid alphanumeric code');
}
if ($i + 1 < $length) {
$code2 = self::getAlphanumericCode(ord($content[$i + 1]));
if (-1 === $code2) {
throw new WriterException('Invalid alphanumeric code');
}
// Encode two alphanumeric letters in 11 bits.
$bits->appendBits($code1 * 45 + $code2, 11);
$i += 2;
} else {
// Encode one alphanumeric letter in six bits.
$bits->appendBits($code1, 6);
++$i;
}
}
}
/**
* Appends regular 8-bit bytes to a bit array.
*
* @throws WriterException if content cannot be encoded to target encoding
*/
private static function append8BitBytes(string $content, BitArray $bits, string $encoding) : void
{
$bytes = @iconv('utf-8', $encoding, $content);
if (false === $bytes) {
throw new WriterException('Could not encode content to ' . $encoding);
}
$length = strlen($bytes);
for ($i = 0; $i < $length; $i++) {
$bits->appendBits(ord($bytes[$i]), 8);
}
}
/**
* Appends KANJI bytes to a bit array.
*
* @throws WriterException if content does not seem to be encoded in SHIFT-JIS
* @throws WriterException if an invalid byte sequence occurs
*/
private static function appendKanjiBytes(string $content, BitArray $bits) : void
{
if (strlen($content) % 2 > 0) {
// We just do a simple length check here. The for loop will check
// individual characters.
throw new WriterException('Content does not seem to be encoded in SHIFT-JIS');
}
$length = strlen($content);
for ($i = 0; $i < $length; $i += 2) {
$byte1 = ord($content[$i]) & 0xff;
$byte2 = ord($content[$i + 1]) & 0xff;
$code = ($byte1 << 8) | $byte2;
if ($code >= 0x8140 && $code <= 0x9ffc) {
$subtracted = $code - 0x8140;
} elseif ($code >= 0xe040 && $code <= 0xebbf) {
$subtracted = $code - 0xc140;
} else {
throw new WriterException('Invalid byte sequence');
}
$encoded = (($subtracted >> 8) * 0xc0) + ($subtracted & 0xff);
$bits->appendBits($encoded, 13);
}
}
/**
* Appends ECI information to a bit array.
*/
private static function appendEci(CharacterSetEci $eci, BitArray $bits) : void
{
$mode = Mode::ECI();
$bits->appendBits($mode->getBits(), 4);
$bits->appendBits($eci->getValue(), 8);
}
}
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