wp/wp-includes/Text/Diff/Engine/string.php
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     1 <?php
       
     2 /**
       
     3  * Parses unified or context diffs output from eg. the diff utility.
       
     4  *
       
     5  * Example:
       
     6  * <code>
       
     7  * $patch = file_get_contents('example.patch');
       
     8  * $diff = new Text_Diff('string', array($patch));
       
     9  * $renderer = new Text_Diff_Renderer_inline();
       
    10  * echo $renderer->render($diff);
       
    11  * </code>
       
    12  *
       
    13  * Copyright 2005 Örjan Persson <o@42mm.org>
       
    14  * Copyright 2005-2010 The Horde Project (http://www.horde.org/)
       
    15  *
       
    16  * See the enclosed file COPYING for license information (LGPL). If you did
       
    17  * not receive this file, see http://opensource.org/licenses/lgpl-license.php.
       
    18  *
       
    19  * @author  Örjan Persson <o@42mm.org>
       
    20  * @package Text_Diff
       
    21  * @since   0.2.0
       
    22  */
       
    23 class Text_Diff_Engine_string {
       
    24 
       
    25     /**
       
    26      * Parses a unified or context diff.
       
    27      *
       
    28      * First param contains the whole diff and the second can be used to force
       
    29      * a specific diff type. If the second parameter is 'autodetect', the
       
    30      * diff will be examined to find out which type of diff this is.
       
    31      *
       
    32      * @param string $diff  The diff content.
       
    33      * @param string $mode  The diff mode of the content in $diff. One of
       
    34      *                      'context', 'unified', or 'autodetect'.
       
    35      *
       
    36      * @return array  List of all diff operations.
       
    37      */
       
    38     function diff($diff, $mode = 'autodetect')
       
    39     {
       
    40         // Detect line breaks.
       
    41         $lnbr = "\n";
       
    42         if (strpos($diff, "\r\n") !== false) {
       
    43             $lnbr = "\r\n";
       
    44         } elseif (strpos($diff, "\r") !== false) {
       
    45             $lnbr = "\r";
       
    46         }
       
    47 
       
    48         // Make sure we have a line break at the EOF.
       
    49         if (substr($diff, -strlen($lnbr)) != $lnbr) {
       
    50             $diff .= $lnbr;
       
    51         }
       
    52 
       
    53         if ($mode != 'autodetect' && $mode != 'context' && $mode != 'unified') {
       
    54             return PEAR::raiseError('Type of diff is unsupported');
       
    55         }
       
    56 
       
    57         if ($mode == 'autodetect') {
       
    58             $context = strpos($diff, '***');
       
    59             $unified = strpos($diff, '---');
       
    60             if ($context === $unified) {
       
    61                 return PEAR::raiseError('Type of diff could not be detected');
       
    62             } elseif ($context === false || $unified === false) {
       
    63                 $mode = $context !== false ? 'context' : 'unified';
       
    64             } else {
       
    65                 $mode = $context < $unified ? 'context' : 'unified';
       
    66             }
       
    67         }
       
    68 
       
    69         // Split by new line and remove the diff header, if there is one.
       
    70         $diff = explode($lnbr, $diff);
       
    71         if (($mode == 'context' && strpos($diff[0], '***') === 0) ||
       
    72             ($mode == 'unified' && strpos($diff[0], '---') === 0)) {
       
    73             array_shift($diff);
       
    74             array_shift($diff);
       
    75         }
       
    76 
       
    77         if ($mode == 'context') {
       
    78             return $this->parseContextDiff($diff);
       
    79         } else {
       
    80             return $this->parseUnifiedDiff($diff);
       
    81         }
       
    82     }
       
    83 
       
    84     /**
       
    85      * Parses an array containing the unified diff.
       
    86      *
       
    87      * @param array $diff  Array of lines.
       
    88      *
       
    89      * @return array  List of all diff operations.
       
    90      */
       
    91     function parseUnifiedDiff($diff)
       
    92     {
       
    93         $edits = array();
       
    94         $end = count($diff) - 1;
       
    95         for ($i = 0; $i < $end;) {
       
    96             $diff1 = array();
       
    97             switch (substr($diff[$i], 0, 1)) {
       
    98             case ' ':
       
    99                 do {
       
   100                     $diff1[] = substr($diff[$i], 1);
       
   101                 } while (++$i < $end && substr($diff[$i], 0, 1) == ' ');
       
   102                 $edits[] = new Text_Diff_Op_copy($diff1);
       
   103                 break;
       
   104 
       
   105             case '+':
       
   106                 // get all new lines
       
   107                 do {
       
   108                     $diff1[] = substr($diff[$i], 1);
       
   109                 } while (++$i < $end && substr($diff[$i], 0, 1) == '+');
       
   110                 $edits[] = new Text_Diff_Op_add($diff1);
       
   111                 break;
       
   112 
       
   113             case '-':
       
   114                 // get changed or removed lines
       
   115                 $diff2 = array();
       
   116                 do {
       
   117                     $diff1[] = substr($diff[$i], 1);
       
   118                 } while (++$i < $end && substr($diff[$i], 0, 1) == '-');
       
   119 
       
   120                 while ($i < $end && substr($diff[$i], 0, 1) == '+') {
       
   121                     $diff2[] = substr($diff[$i++], 1);
       
   122                 }
       
   123                 if (count($diff2) == 0) {
       
   124                     $edits[] = new Text_Diff_Op_delete($diff1);
       
   125                 } else {
       
   126                     $edits[] = new Text_Diff_Op_change($diff1, $diff2);
       
   127                 }
       
   128                 break;
       
   129 
       
   130             default:
       
   131                 $i++;
       
   132                 break;
       
   133             }
       
   134         }
       
   135 
       
   136         return $edits;
       
   137     }
       
   138 
       
   139     /**
       
   140      * Parses an array containing the context diff.
       
   141      *
       
   142      * @param array $diff  Array of lines.
       
   143      *
       
   144      * @return array  List of all diff operations.
       
   145      */
       
   146     function parseContextDiff(&$diff)
       
   147     {
       
   148         $edits = array();
       
   149         $i = $max_i = $j = $max_j = 0;
       
   150         $end = count($diff) - 1;
       
   151         while ($i < $end && $j < $end) {
       
   152             while ($i >= $max_i && $j >= $max_j) {
       
   153                 // Find the boundaries of the diff output of the two files
       
   154                 for ($i = $j;
       
   155                      $i < $end && substr($diff[$i], 0, 3) == '***';
       
   156                      $i++);
       
   157                 for ($max_i = $i;
       
   158                      $max_i < $end && substr($diff[$max_i], 0, 3) != '---';
       
   159                      $max_i++);
       
   160                 for ($j = $max_i;
       
   161                      $j < $end && substr($diff[$j], 0, 3) == '---';
       
   162                      $j++);
       
   163                 for ($max_j = $j;
       
   164                      $max_j < $end && substr($diff[$max_j], 0, 3) != '***';
       
   165                      $max_j++);
       
   166             }
       
   167 
       
   168             // find what hasn't been changed
       
   169             $array = array();
       
   170             while ($i < $max_i &&
       
   171                    $j < $max_j &&
       
   172                    strcmp($diff[$i], $diff[$j]) == 0) {
       
   173                 $array[] = substr($diff[$i], 2);
       
   174                 $i++;
       
   175                 $j++;
       
   176             }
       
   177 
       
   178             while ($i < $max_i && ($max_j-$j) <= 1) {
       
   179                 if ($diff[$i] != '' && substr($diff[$i], 0, 1) != ' ') {
       
   180                     break;
       
   181                 }
       
   182                 $array[] = substr($diff[$i++], 2);
       
   183             }
       
   184 
       
   185             while ($j < $max_j && ($max_i-$i) <= 1) {
       
   186                 if ($diff[$j] != '' && substr($diff[$j], 0, 1) != ' ') {
       
   187                     break;
       
   188                 }
       
   189                 $array[] = substr($diff[$j++], 2);
       
   190             }
       
   191             if (count($array) > 0) {
       
   192                 $edits[] = new Text_Diff_Op_copy($array);
       
   193             }
       
   194 
       
   195             if ($i < $max_i) {
       
   196                 $diff1 = array();
       
   197                 switch (substr($diff[$i], 0, 1)) {
       
   198                 case '!':
       
   199                     $diff2 = array();
       
   200                     do {
       
   201                         $diff1[] = substr($diff[$i], 2);
       
   202                         if ($j < $max_j && substr($diff[$j], 0, 1) == '!') {
       
   203                             $diff2[] = substr($diff[$j++], 2);
       
   204                         }
       
   205                     } while (++$i < $max_i && substr($diff[$i], 0, 1) == '!');
       
   206                     $edits[] = new Text_Diff_Op_change($diff1, $diff2);
       
   207                     break;
       
   208 
       
   209                 case '+':
       
   210                     do {
       
   211                         $diff1[] = substr($diff[$i], 2);
       
   212                     } while (++$i < $max_i && substr($diff[$i], 0, 1) == '+');
       
   213                     $edits[] = new Text_Diff_Op_add($diff1);
       
   214                     break;
       
   215 
       
   216                 case '-':
       
   217                     do {
       
   218                         $diff1[] = substr($diff[$i], 2);
       
   219                     } while (++$i < $max_i && substr($diff[$i], 0, 1) == '-');
       
   220                     $edits[] = new Text_Diff_Op_delete($diff1);
       
   221                     break;
       
   222                 }
       
   223             }
       
   224 
       
   225             if ($j < $max_j) {
       
   226                 $diff2 = array();
       
   227                 switch (substr($diff[$j], 0, 1)) {
       
   228                 case '+':
       
   229                     do {
       
   230                         $diff2[] = substr($diff[$j++], 2);
       
   231                     } while ($j < $max_j && substr($diff[$j], 0, 1) == '+');
       
   232                     $edits[] = new Text_Diff_Op_add($diff2);
       
   233                     break;
       
   234 
       
   235                 case '-':
       
   236                     do {
       
   237                         $diff2[] = substr($diff[$j++], 2);
       
   238                     } while ($j < $max_j && substr($diff[$j], 0, 1) == '-');
       
   239                     $edits[] = new Text_Diff_Op_delete($diff2);
       
   240                     break;
       
   241                 }
       
   242             }
       
   243         }
       
   244 
       
   245         return $edits;
       
   246     }
       
   247 
       
   248 }