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   1  <?php
   2  
   3  /**
   4  * @package   s9e\TextFormatter
   5  * @copyright Copyright (c) 2010-2022 The s9e authors
   6  * @license   http://www.opensource.org/licenses/mit-license.php The MIT License
   7  */
   8  namespace s9e\TextFormatter\Configurator\RendererGenerators\PHP;
   9  
  10  abstract class AbstractOptimizer
  11  {
  12      /**
  13      * @var integer Number of tokens
  14      */
  15      protected $cnt;
  16  
  17      /**
  18      * @var integer Current token index
  19      */
  20      protected $i;
  21  
  22      /**
  23      * @var boolean Whether the tokens have been changed
  24      */
  25      protected $changed;
  26  
  27      /**
  28      * @var array Tokens from current source
  29      */
  30      protected $tokens;
  31  
  32      /**
  33      * Optimize the control structures of a script
  34      *
  35      * Removes brackets in control structures wherever possible. Prevents the generation of EXT_STMT
  36      * opcodes where they're not strictly required.
  37      *
  38      * @param  string $php Original code
  39      * @return string      Optimized code
  40      */
  41  	public function optimize($php)
  42      {
  43          $this->reset($php);
  44          $this->optimizeTokens();
  45  
  46          // Rebuild the source if it has changed
  47          if ($this->changed)
  48          {
  49              $php = $this->serialize();
  50          }
  51  
  52          // Free the memory taken up by the tokens
  53          unset($this->tokens);
  54  
  55          return $php;
  56      }
  57  
  58      /**
  59      * Optimize the stored tokens
  60      *
  61      * @return void
  62      */
  63      abstract protected function optimizeTokens();
  64  
  65      /**
  66      * Reset the internal state of this optimizer
  67      *
  68      * @param  string $php PHP source
  69      * @return void
  70      */
  71  	protected function reset($php)
  72      {
  73          $this->tokens  = token_get_all('<?php ' . $php);
  74          $this->i       = 0;
  75          $this->cnt     = count($this->tokens);
  76          $this->changed = false;
  77      }
  78  
  79      /**
  80      * Serialize the tokens back to source
  81      *
  82      * @return string
  83      */
  84  	protected function serialize()
  85      {
  86          // Remove the first token, which should be T_OPEN_TAG, aka "<?php"
  87          unset($this->tokens[0]);
  88  
  89          $php = '';
  90          foreach ($this->tokens as $token)
  91          {
  92              $php .= (is_string($token)) ? $token : $token[1];
  93          }
  94  
  95          return $php;
  96      }
  97  
  98      /**
  99      * Move the internal cursor until it reaches given string
 100      *
 101      * @param  string $str String to reach
 102      * @return void
 103      */
 104  	protected function skipToString($str)
 105      {
 106          while (++$this->i < $this->cnt && $this->tokens[$this->i] !== $str);
 107      }
 108  
 109      /**
 110      * Skip all whitespace
 111      *
 112      * @return void
 113      */
 114  	protected function skipWhitespace()
 115      {
 116          while (++$this->i < $this->cnt && $this->tokens[$this->i][0] === T_WHITESPACE);
 117      }
 118  
 119      /**
 120      * Remove one tab of indentation off a range of PHP tokens
 121      *
 122      * @param  integer $start  Index of the first token to unindent
 123      * @param  integer $end    Index of the last token to unindent
 124      * @return void
 125      */
 126  	protected function unindentBlock($start, $end)
 127      {
 128          $this->i = $start;
 129          do
 130          {
 131              if ($this->tokens[$this->i][0] === T_WHITESPACE || $this->tokens[$this->i][0] === T_DOC_COMMENT)
 132              {
 133                  $this->tokens[$this->i][1] = preg_replace("/^\t/m", '', $this->tokens[$this->i][1]);
 134              }
 135          }
 136          while (++$this->i <= $end);
 137      }
 138  }