text: <?php
  /**
   * PHPCompatibility, an external standard for PHP_CodeSniffer.
   *
   * @package   PHPCompatibility
   * @copyright 2012-2020 PHPCompatibility Contributors
   * @license   https://opensource.org/licenses/LGPL-3.0 LGPL3
   * @link      https://github.com/PHPCompatibility/PHPCompatibility
   */
  
  namespace PHPCompatibility\Sniffs\ParameterValues;
  
  use PHPCompatibility\AbstractFunctionCallParameterSniff;
  use PHP_CodeSniffer\Files\File;
  
  /**
   * Detect negative string offsets as parameters passed to functions where this
   * was not allowed prior to PHP 7.1.
   *
   * PHP version 7.1
   *
   * @link https://wiki.php.net/rfc/negative-string-offsets
   *
   * @since 9.0.0
   */
  class NewNegativeStringOffsetSniff extends AbstractFunctionCallParameterSniff
  {
  
      /**
       * Functions to check for.
       *
       * @since 9.0.0
       *
       * @var array Function name => 1-based parameter offset of the affected parameters => parameter name.
       */
      protected $targetFunctions = [
          'file_get_contents'     => [
              4 => 'offset',
          ],
          'grapheme_extract'      => [
              4 => 'start',
          ],
          'grapheme_stripos'      => [
              3 => 'offset',
          ],
          'grapheme_strpos'       => [
              3 => 'offset',
          ],
          'iconv_strpos'          => [
              3 => 'offset',
          ],
          'mb_ereg_search_setpos' => [
              1 => 'position',
          ],
          'mb_strimwidth'         => [
              2 => 'start',
              3 => 'width',
          ],
          'mb_stripos'            => [
              3 => 'offset',
          ],
          'mb_strpos'             => [
              3 => 'offset',
          ],
          'stripos'               => [
              3 => 'offset',
          ],
          'strpos'                => [
              3 => 'offset',
          ],
          'substr_count'          => [
              3 => 'offset',
              4 => 'length',
          ],
      ];
  
  
      /**
       * Do a version check to determine if this sniff needs to run at all.
       *
       * @since 9.0.0
       *
       * @return bool
       */
      protected function bowOutEarly()
      {
          return ($this->supportsBelow('7.0') === false);
      }
  
      /**
       * Process the parameters of a matched function.
       *
       * @since 9.0.0
       *
       * @param \PHP_CodeSniffer\Files\File $phpcsFile    The file being scanned.
       * @param int                         $stackPtr     The position of the current token in the stack.
       * @param string                      $functionName The token content (function name) which was matched.
       * @param array                       $parameters   Array with information about the parameters.
       *
       * @return int|void Integer stack pointer to skip forward or void to continue
       *                  normal file processing.
       */
      public function processParameters(File $phpcsFile, $stackPtr, $functionName, $parameters)
      {
          $functionLC = \strtolower($functionName);
          foreach ($this->targetFunctions[$functionLC] as $pos => $name) {
              if (isset($parameters[$pos]) === false) {
                  continue;
              }
  
              $targetParam = $parameters[$pos];
  
              if ($this->isNegativeNumber($phpcsFile, $targetParam['start'], $targetParam['end']) === false) {
                  continue;
              }
  
              $phpcsFile->addError(
                  'Negative string offsets were not supported for the $%s parameter in %s() in PHP 7.0 or lower. Found: %s',
                  $targetParam['start'],
                  'Found',
                  [
                      $name,
                      $functionName,
                      $targetParam['clean'],
                  ]
              );
          }
      }
  }
  