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<?php
/**
* fast-image-size image type webp
*
* @package fast-image-size
* @copyright (c) Marc Alexander <admin@m-a-styles.de>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Nextend\Framework\FastImageSize\Type;
use Nextend\Framework\FastImageSize\FastImageSize;
class TypeWebp extends TypeBase {
/** @var string RIFF header */
const WEBP_RIFF_HEADER = "RIFF";
/** @var string Webp header */
const WEBP_HEADER = "WEBP";
/** @var string VP8 chunk header */
const VP8_HEADER = "VP8";
/** @var string Simple(lossy) webp format */
const WEBP_FORMAT_SIMPLE = ' ';
/** @var string Lossless webp format */
const WEBP_FORMAT_LOSSLESS = 'L';
/** @var string Extended webp format */
const WEBP_FORMAT_EXTENDED = 'X';
/** @var int WEBP header size needed for retrieving image size */
const WEBP_HEADER_SIZE = 30;
/** @var array Size info array */
protected $size;
/**
* Constructor for webp image type. Adds missing constant if necessary.
*
* @param FastImageSize $fastImageSize
*/
public function __construct(FastImageSize $fastImageSize) {
parent::__construct($fastImageSize);
if (!defined('IMAGETYPE_WEBP')) {
define('IMAGETYPE_WEBP', 18);
}
}
/**
* {@inheritdoc}
*/
public function getSize($filename) {
// Do not force length of header
$data = $this->fastImageSize->getImage($filename, 0, self::WEBP_HEADER_SIZE);
$this->size = array();
$webpFormat = substr($data, 15, 1);
if (!$this->hasWebpHeader($data) || !$this->isValidFormat($webpFormat)) {
return;
}
$data = substr($data, 16, 14);
$this->getWebpSize($data, $webpFormat);
$this->fastImageSize->setSize($this->size);
$this->fastImageSize->setImageType(IMAGETYPE_WEBP);
}
/**
* Check if $data has valid WebP header
*
* @param string $data Image data
*
* @return bool True if $data has valid WebP header, false if not
*/
protected function hasWebpHeader($data) {
$riffSignature = substr($data, 0, self::LONG_SIZE);
$webpSignature = substr($data, 8, self::LONG_SIZE);
$vp8Signature = substr($data, 12, self::SHORT_SIZE + 1);
return !empty($data) && $riffSignature === self::WEBP_RIFF_HEADER && $webpSignature === self::WEBP_HEADER && $vp8Signature === self::VP8_HEADER;
}
/**
* Check if $format is a valid WebP format
*
* @param string $format Format string
*
* @return bool True if format is valid WebP format, false if not
*/
protected function isValidFormat($format) {
return in_array($format, array(
self::WEBP_FORMAT_SIMPLE,
self::WEBP_FORMAT_LOSSLESS,
self::WEBP_FORMAT_EXTENDED
));
}
/**
* Get webp size info depending on format type and set size array values
*
* @param string $data Data string
* @param string $format Format string
*/
protected function getWebpSize($data, $format) {
switch ($format) {
case self::WEBP_FORMAT_SIMPLE:
$this->size = unpack('vwidth/vheight', substr($data, 10, 4));
break;
case self::WEBP_FORMAT_LOSSLESS:
// Lossless uses 14-bit values so we'll have to use bitwise shifting
$this->size = array(
'width' => ord($data[5]) + ((ord($data[6]) & 0x3F) << 8) + 1,
'height' => (ord($data[6]) >> 6) + (ord($data[7]) << 2) + ((ord($data[8]) & 0xF) << 10) + 1,
);
break;
case self::WEBP_FORMAT_EXTENDED:
// Extended uses 24-bit values cause 14-bit for lossless wasn't weird enough
$this->size = array(
'width' => ord($data[8]) + (ord($data[9]) << 8) + (ord($data[10]) << 16) + 1,
'height' => ord($data[11]) + (ord($data[12]) << 8) + (ord($data[13]) << 16) + 1,
);
break;
}
}
}