<?php
/**
* StegoSystem Base LSB UnitTest
*
* @link https://github.com/picamator/SteganographyKit
* @license http://opensource.org/licenses/BSD-3-Clause New BSD License
*/
use Picamator\SteganographyKit\SecretText\PlainText;
use Picamator\SteganographyKit\Image\Image;
use Picamator\SteganographyKit\StegoSystem\StegoSystemInterface;
abstract class BaseLsbTest extends BaseTest
{
/**
* SecretText file
*
* @var string
*/
protected $secretFile = 'secret_text.txt';
/**
* CoverText options
*
* @var array
*/
static protected $optionsCoverText = array(
'path' => 'original_200_200.png',
'savePath' => 'original_%s.png'
);
/**
* Remove files in stegoPath after runs each test
*/
public function tearDown()
{
$this->clearStegoPath();
}
/**
* Base Encode Decode
*
* @param array $optionsCoverText
* @param array $optionsSecretText
* @param array $channels
* @param StegoSystemInterface $stegoSystem
*/
protected function encodeDecode(array $optionsCoverText,
array $optionsSecretText, array $channels, StegoSystemInterface $stegoSystem
) {
// encode
$optionsCoverText['path'] = $this->getDataPath($optionsCoverText['path']);
$optionsCoverText['savePath'] = dirname($optionsCoverText['path']) . '/'
. $optionsCoverText['savePath'];
$coverText = new Image($optionsCoverText);
$secretText = new PlainText($optionsSecretText);
$encode = $stegoSystem->setChannels($channels)->encode($secretText, $coverText);
$this->assertTrue($encode);
// decode
$stegoText = new Image(array('path' => $optionsCoverText['savePath']));
$decodeText = $stegoSystem->decode($stegoText, $secretText);
$this->assertEquals($optionsSecretText['text'], $decodeText);
}
/**
* Generate data provider
* It's use secret_text.txt as a secret text and
* original_200_200.png as a cover tet
*
* @param integer $resultCount - number of providers data
* @param integer $textLength - text length, if not set random data is used
* @param integer $channel - channel, if not set random data is used
*/
protected function generateProvider($resultCount,
$textLength = null, array $channel = []
) {
$supportedChannel = array('red', 'green', 'blue');
$supportedChannelSize = count($supportedChannel);
// 200*200*3/8 = 15000 characters max to cover
// 19433 secret text length
$secretText = $this->getSecretFileData();
$secretTextLength = strlen($secretText);
// validate parameters
self::validatePrameters($textLength, $secretTextLength, $channel, $supportedChannelSize);
// generate provider data set
$providerData = [];
for($i = 0; $i < $resultCount; $i++) {
// generate secretText item
$secretTextItem = (is_null($textLength))?
self::getRandomText($secretText, $secretTextLength):
substr($secretText, 0, $textLength);
// generate use channel
$useChannel = (empty($channel))?
self::getRandomChannel($supportedChannel, $supportedChannelSize):
$channel;
// set coverText options
$providerData[$i][] = self::getProviderDataItem($useChannel, $secretTextItem);
// set secretText option
$providerData[$i][] = array('text' => $secretTextItem);
// set use channel
$providerData[$i][] = $useChannel;
}
return $providerData;
}
/**
* Gets secret data from file
*
* @return string|false
* @throws \PHPUnit_Framework_Exception
*/
protected function getSecretFileData()
{
$result = file_get_contents($this->getDataPath($this->secretFile));
if ($result === false) {
throw new \PHPUnit_Framework_Exception('Can not read secretFile: ' . $this->secretFile);
}
return $result;
}
/**
* Validate provider paramters
*
* @param integer $textLength
* @param integer $secretTextLength
* @param array $channel
* @param integer $supportedChannelSize
* @throws \PHPUnit_Framework_Exception
*/
static protected function validatePrameters($textLength,
$secretTextLength, array $channel, $supportedChannelSize
) {
if ((!is_null($textLength) && $textLength > $secretTextLength)
|| (!empty($channel) && count($channel) > $supportedChannelSize)) {
throw new \PHPUnit_Framework_Exception('Used parameters are out of data source length: text ['
. $secretTextLength . '], channels [' . $supportedChannelSize . ']');
}
}
/**
* Gets provider's data item
*
* @param array $useChannel
* @param string $secretTextItem
* @return array - array('path' => ..., 'savePath' => ...);
*/
static protected function getProviderDataItem(array $useChannel, $secretTextItem)
{
$args = microtime(true) . '_secret_length_' . strlen($secretTextItem)
. '_' . implode('_', $useChannel);
$result = array(
'path' => self::$optionsCoverText['path'],
'savePath' => self::$stegoPath . '/' . sprintf(self::$optionsCoverText['savePath'], $args)
);
return $result;
}
/**
* Gets random channel
*
* @return array
*/
static protected function getRandomChannel(array $channel, $channelSize = null)
{
$channelSize = $channelSize ? : count($channel);
$useChannelSize = mt_rand(1, $channelSize);
$useChannelKey = (array)array_rand($channel, $useChannelSize);
$result = [];
foreach($useChannelKey as $value) {
$result[] = $channel[$value];
}
return $result;
}
static protected function getRandomText($text, $textLength = null)
{
$textLength = $textLength ? : strlen($text);
$itemStart = mt_rand(0, $textLength - 1);
$itemLength = mt_rand(1, $textLength);
$result = substr($text, $itemStart, $itemLength);
return str_shuffle($result);
}
}
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