Unicode.php 24.6 KB
Newer Older
1 2 3 4 5 6
<?php

namespace Drupal\Component\Utility;

/**
 * Provides Unicode-related conversions and operations.
7 8
 *
 * @ingroup utility
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
 */
class Unicode {

  /**
   * Matches Unicode characters that are word boundaries.
   *
   * Characters with the following General_category (gc) property values are used
   * as word boundaries. While this does not fully conform to the Word Boundaries
   * algorithm described in http://unicode.org/reports/tr29, as PCRE does not
   * contain the Word_Break property table, this simpler algorithm has to do.
   * - Cc, Cf, Cn, Co, Cs: Other.
   * - Pc, Pd, Pe, Pf, Pi, Po, Ps: Punctuation.
   * - Sc, Sk, Sm, So: Symbols.
   * - Zl, Zp, Zs: Separators.
   *
   * Non-boundary characters include the following General_category (gc) property
   * values:
   * - Ll, Lm, Lo, Lt, Lu: Letters.
   * - Mc, Me, Mn: Combining Marks.
   * - Nd, Nl, No: Numbers.
   *
   * Note that the PCRE property matcher is not used because we wanted to be
   * compatible with Unicode 5.2.0 regardless of the PCRE version used (and any
   * bugs in PCRE property tables).
   *
   * @see http://unicode.org/glossary
   */
36
  const PREG_CLASS_WORD_BOUNDARY = <<<'EOD'
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90
\x{0}-\x{2F}\x{3A}-\x{40}\x{5B}-\x{60}\x{7B}-\x{A9}\x{AB}-\x{B1}\x{B4}
\x{B6}-\x{B8}\x{BB}\x{BF}\x{D7}\x{F7}\x{2C2}-\x{2C5}\x{2D2}-\x{2DF}
\x{2E5}-\x{2EB}\x{2ED}\x{2EF}-\x{2FF}\x{375}\x{37E}-\x{385}\x{387}\x{3F6}
\x{482}\x{55A}-\x{55F}\x{589}-\x{58A}\x{5BE}\x{5C0}\x{5C3}\x{5C6}
\x{5F3}-\x{60F}\x{61B}-\x{61F}\x{66A}-\x{66D}\x{6D4}\x{6DD}\x{6E9}
\x{6FD}-\x{6FE}\x{700}-\x{70F}\x{7F6}-\x{7F9}\x{830}-\x{83E}
\x{964}-\x{965}\x{970}\x{9F2}-\x{9F3}\x{9FA}-\x{9FB}\x{AF1}\x{B70}
\x{BF3}-\x{BFA}\x{C7F}\x{CF1}-\x{CF2}\x{D79}\x{DF4}\x{E3F}\x{E4F}
\x{E5A}-\x{E5B}\x{F01}-\x{F17}\x{F1A}-\x{F1F}\x{F34}\x{F36}\x{F38}
\x{F3A}-\x{F3D}\x{F85}\x{FBE}-\x{FC5}\x{FC7}-\x{FD8}\x{104A}-\x{104F}
\x{109E}-\x{109F}\x{10FB}\x{1360}-\x{1368}\x{1390}-\x{1399}\x{1400}
\x{166D}-\x{166E}\x{1680}\x{169B}-\x{169C}\x{16EB}-\x{16ED}
\x{1735}-\x{1736}\x{17B4}-\x{17B5}\x{17D4}-\x{17D6}\x{17D8}-\x{17DB}
\x{1800}-\x{180A}\x{180E}\x{1940}-\x{1945}\x{19DE}-\x{19FF}
\x{1A1E}-\x{1A1F}\x{1AA0}-\x{1AA6}\x{1AA8}-\x{1AAD}\x{1B5A}-\x{1B6A}
\x{1B74}-\x{1B7C}\x{1C3B}-\x{1C3F}\x{1C7E}-\x{1C7F}\x{1CD3}\x{1FBD}
\x{1FBF}-\x{1FC1}\x{1FCD}-\x{1FCF}\x{1FDD}-\x{1FDF}\x{1FED}-\x{1FEF}
\x{1FFD}-\x{206F}\x{207A}-\x{207E}\x{208A}-\x{208E}\x{20A0}-\x{20B8}
\x{2100}-\x{2101}\x{2103}-\x{2106}\x{2108}-\x{2109}\x{2114}
\x{2116}-\x{2118}\x{211E}-\x{2123}\x{2125}\x{2127}\x{2129}\x{212E}
\x{213A}-\x{213B}\x{2140}-\x{2144}\x{214A}-\x{214D}\x{214F}
\x{2190}-\x{244A}\x{249C}-\x{24E9}\x{2500}-\x{2775}\x{2794}-\x{2B59}
\x{2CE5}-\x{2CEA}\x{2CF9}-\x{2CFC}\x{2CFE}-\x{2CFF}\x{2E00}-\x{2E2E}
\x{2E30}-\x{3004}\x{3008}-\x{3020}\x{3030}\x{3036}-\x{3037}
\x{303D}-\x{303F}\x{309B}-\x{309C}\x{30A0}\x{30FB}\x{3190}-\x{3191}
\x{3196}-\x{319F}\x{31C0}-\x{31E3}\x{3200}-\x{321E}\x{322A}-\x{3250}
\x{3260}-\x{327F}\x{328A}-\x{32B0}\x{32C0}-\x{33FF}\x{4DC0}-\x{4DFF}
\x{A490}-\x{A4C6}\x{A4FE}-\x{A4FF}\x{A60D}-\x{A60F}\x{A673}\x{A67E}
\x{A6F2}-\x{A716}\x{A720}-\x{A721}\x{A789}-\x{A78A}\x{A828}-\x{A82B}
\x{A836}-\x{A839}\x{A874}-\x{A877}\x{A8CE}-\x{A8CF}\x{A8F8}-\x{A8FA}
\x{A92E}-\x{A92F}\x{A95F}\x{A9C1}-\x{A9CD}\x{A9DE}-\x{A9DF}
\x{AA5C}-\x{AA5F}\x{AA77}-\x{AA79}\x{AADE}-\x{AADF}\x{ABEB}
\x{E000}-\x{F8FF}\x{FB29}\x{FD3E}-\x{FD3F}\x{FDFC}-\x{FDFD}
\x{FE10}-\x{FE19}\x{FE30}-\x{FE6B}\x{FEFF}-\x{FF0F}\x{FF1A}-\x{FF20}
\x{FF3B}-\x{FF40}\x{FF5B}-\x{FF65}\x{FFE0}-\x{FFFD}
EOD;

  /**
   * Indicates that standard PHP (emulated) unicode support is being used.
   */
  const STATUS_SINGLEBYTE = 0;

  /**
   * Indicates that full unicode support with the PHP mbstring extension is
   * being used.
   */
  const STATUS_MULTIBYTE = 1;

  /**
   * Indicates an error during check for PHP unicode support.
   */
  const STATUS_ERROR = -1;

  /**
91
   * Holds the multibyte capabilities of the current environment.
92 93 94 95 96 97
   *
   * @var int
   */
  protected static $status = 0;

  /**
98
   * Gets the current status of unicode/multibyte support on this environment.
99 100 101 102 103 104 105 106
   *
   * @return int
   *   The status of multibyte support. It can be one of:
   *   - \Drupal\Component\Utility\Unicode::STATUS_MULTIBYTE
   *     Full unicode support using an extension.
   *   - \Drupal\Component\Utility\Unicode::STATUS_SINGLEBYTE
   *     Standard PHP (emulated) unicode support.
   *   - \Drupal\Component\Utility\Unicode::STATUS_ERROR
107
   *     An error occurred. No unicode support.
108 109 110 111 112 113
   */
  public static function getStatus() {
    return static::$status;
  }

  /**
114
   * Sets the value for multibyte support status for the current environment.
115 116 117 118 119 120 121
   *
   * The following status keys are supported:
   *   - \Drupal\Component\Utility\Unicode::STATUS_MULTIBYTE
   *     Full unicode support using an extension.
   *   - \Drupal\Component\Utility\Unicode::STATUS_SINGLEBYTE
   *     Standard PHP (emulated) unicode support.
   *   - \Drupal\Component\Utility\Unicode::STATUS_ERROR
122
   *     An error occurred. No unicode support.
123 124 125 126 127
   *
   * @param int $status
   *   The new status of multibyte support.
   */
  public static function setStatus($status) {
128
    if (!in_array($status, [static::STATUS_SINGLEBYTE, static::STATUS_MULTIBYTE, static::STATUS_ERROR])) {
129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160
      throw new \InvalidArgumentException('Invalid status value for unicode support.');
    }
    static::$status = $status;
  }

  /**
   * Checks for Unicode support in PHP and sets the proper settings if possible.
   *
   * Because of the need to be able to handle text in various encodings, we do
   * not support mbstring function overloading. HTTP input/output conversion
   * must be disabled for similar reasons.
   *
   * @return string
   *   A string identifier of a failed multibyte extension check, if any.
   *   Otherwise, an empty string.
   */
  public static function check() {
    // Check for mbstring extension.
    if (!function_exists('mb_strlen')) {
      static::$status = static::STATUS_SINGLEBYTE;
      return 'mb_strlen';
    }

    // Check mbstring configuration.
    if (ini_get('mbstring.func_overload') != 0) {
      static::$status = static::STATUS_ERROR;
      return 'mbstring.func_overload';
    }
    if (ini_get('mbstring.encoding_translation') != 0) {
      static::$status = static::STATUS_ERROR;
      return 'mbstring.encoding_translation';
    }
161 162 163 164 165 166 167 168 169 170 171
    // mbstring.http_input and mbstring.http_output are deprecated and empty by
    // default in PHP 5.6.
    if (version_compare(PHP_VERSION, '5.6.0') == -1) {
      if (ini_get('mbstring.http_input') != 'pass') {
        static::$status = static::STATUS_ERROR;
        return 'mbstring.http_input';
      }
      if (ini_get('mbstring.http_output') != 'pass') {
        static::$status = static::STATUS_ERROR;
        return 'mbstring.http_output';
      }
172 173 174 175 176 177 178 179 180
    }

    // Set appropriate configuration.
    mb_internal_encoding('utf-8');
    mb_language('uni');
    static::$status = static::STATUS_MULTIBYTE;
    return '';
  }

181 182 183 184 185 186 187 188 189 190 191
  /**
   * Decodes UTF byte-order mark (BOM) into the encoding's name.
   *
   * @param string $data
   *   The data possibly containing a BOM. This can be the entire contents of
   *   a file, or just a fragment containing at least the first five bytes.
   *
   * @return string|bool
   *   The name of the encoding, or FALSE if no byte order mark was present.
   */
  public static function encodingFromBOM($data) {
192
    static $bomMap = [
193 194 195 196 197 198 199 200 201 202
      "\xEF\xBB\xBF" => 'UTF-8',
      "\xFE\xFF" => 'UTF-16BE',
      "\xFF\xFE" => 'UTF-16LE',
      "\x00\x00\xFE\xFF" => 'UTF-32BE',
      "\xFF\xFE\x00\x00" => 'UTF-32LE',
      "\x2B\x2F\x76\x38" => 'UTF-7',
      "\x2B\x2F\x76\x39" => 'UTF-7',
      "\x2B\x2F\x76\x2B" => 'UTF-7',
      "\x2B\x2F\x76\x2F" => 'UTF-7',
      "\x2B\x2F\x76\x38\x2D" => 'UTF-7',
203
    ];
204 205 206 207 208 209 210 211 212

    foreach ($bomMap as $bom => $encoding) {
      if (strpos($data, $bom) === 0) {
        return $encoding;
      }
    }
    return FALSE;
  }

213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266
  /**
   * Converts data to UTF-8.
   *
   * Requires the iconv, GNU recode or mbstring PHP extension.
   *
   * @param string $data
   *   The data to be converted.
   * @param string $encoding
   *   The encoding that the data is in.
   *
   * @return string|bool
   *   Converted data or FALSE.
   */
  public static function convertToUtf8($data, $encoding) {
    if (function_exists('iconv')) {
      return @iconv($encoding, 'utf-8', $data);
    }
    elseif (function_exists('mb_convert_encoding')) {
      return @mb_convert_encoding($data, 'utf-8', $encoding);
    }
    elseif (function_exists('recode_string')) {
      return @recode_string($encoding . '..utf-8', $data);
    }
    // Cannot convert.
    return FALSE;
  }

  /**
   * Truncates a UTF-8-encoded string safely to a number of bytes.
   *
   * If the end position is in the middle of a UTF-8 sequence, it scans backwards
   * until the beginning of the byte sequence.
   *
   * Use this function whenever you want to chop off a string at an unsure
   * location. On the other hand, if you're sure that you're splitting on a
   * character boundary (e.g. after using strpos() or similar), you can safely
   * use substr() instead.
   *
   * @param string $string
   *   The string to truncate.
   * @param int $len
   *   An upper limit on the returned string length.
   *
   * @return string
   *   The truncated string.
   */
  public static function truncateBytes($string, $len) {
    if (strlen($string) <= $len) {
      return $string;
    }
    if ((ord($string[$len]) < 0x80) || (ord($string[$len]) >= 0xC0)) {
      return substr($string, 0, $len);
    }
    // Scan backwards to beginning of the byte sequence.
267 268 269
    // @todo Make the code more readable in https://www.drupal.org/node/2911497.
    while (--$len >= 0 && ord($string[$len]) >= 0x80 && ord($string[$len]) < 0xC0) {
    }
270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295

    return substr($string, 0, $len);
  }

  /**
   * Counts the number of characters in a UTF-8 string.
   *
   * This is less than or equal to the byte count.
   *
   * @param string $text
   *   The string to run the operation on.
   *
   * @return int
   *   The length of the string.
   */
  public static function strlen($text) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return mb_strlen($text);
    }
    else {
      // Do not count UTF-8 continuation bytes.
      return strlen(preg_replace("/[\x80-\xBF]/", '', $text));
    }
  }

  /**
296
   * Converts a UTF-8 string to uppercase.
297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317
   *
   * @param string $text
   *   The string to run the operation on.
   *
   * @return string
   *   The string in uppercase.
   */
  public static function strtoupper($text) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return mb_strtoupper($text);
    }
    else {
      // Use C-locale for ASCII-only uppercase.
      $text = strtoupper($text);
      // Case flip Latin-1 accented letters.
      $text = preg_replace_callback('/\xC3[\xA0-\xB6\xB8-\xBE]/', '\Drupal\Component\Utility\Unicode::caseFlip', $text);
      return $text;
    }
  }

  /**
318
   * Converts a UTF-8 string to lowercase.
319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339
   *
   * @param string $text
   *   The string to run the operation on.
   *
   * @return string
   *   The string in lowercase.
   */
  public static function strtolower($text) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return mb_strtolower($text);
    }
    else {
      // Use C-locale for ASCII-only lowercase.
      $text = strtolower($text);
      // Case flip Latin-1 accented letters.
      $text = preg_replace_callback('/\xC3[\x80-\x96\x98-\x9E]/', '\Drupal\Component\Utility\Unicode::caseFlip', $text);
      return $text;
    }
  }

  /**
340
   * Capitalizes the first character of a UTF-8 string.
341 342 343 344 345
   *
   * @param string $text
   *   The string to convert.
   *
   * @return string
346
   *   The string with the first character as uppercase.
347 348 349 350 351
   */
  public static function ucfirst($text) {
    return static::strtoupper(static::substr($text, 0, 1)) . static::substr($text, 1);
  }

352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380
  /**
   * Converts the first character of a UTF-8 string to lowercase.
   *
   * @param string $text
   *   The string that will be converted.
   *
   * @return string
   *   The string with the first character as lowercase.
   *
   * @ingroup php_wrappers
   */
  public static function lcfirst($text) {
    // Note: no mbstring equivalent!
    return static::strtolower(static::substr($text, 0, 1)) . static::substr($text, 1);
  }

  /**
   * Capitalizes the first character of each word in a UTF-8 string.
   *
   * @param string $text
   *   The text that will be converted.
   *
   * @return string
   *   The input $text with each word capitalized.
   *
   * @ingroup php_wrappers
   */
  public static function ucwords($text) {
    $regex = '/(^|[' . static::PREG_CLASS_WORD_BOUNDARY . '])([^' . static::PREG_CLASS_WORD_BOUNDARY . '])/u';
381
    return preg_replace_callback($regex, function (array $matches) {
382 383 384 385
      return $matches[1] . Unicode::strtoupper($matches[2]);
    }, $text);
  }

386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411
  /**
   * Cuts off a piece of a string based on character indices and counts.
   *
   * Follows the same behavior as PHP's own substr() function. Note that for
   * cutting off a string at a known character/substring location, the usage of
   * PHP's normal strpos/substr is safe and much faster.
   *
   * @param string $text
   *   The input string.
   * @param int $start
   *   The position at which to start reading.
   * @param int $length
   *   The number of characters to read.
   *
   * @return string
   *   The shortened string.
   */
  public static function substr($text, $start, $length = NULL) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return $length === NULL ? mb_substr($text, $start) : mb_substr($text, $start, $length);
    }
    else {
      $strlen = strlen($text);
      // Find the starting byte offset.
      $bytes = 0;
      if ($start > 0) {
412 413
        // Count all the characters except continuation bytes from the start
        // until we have found $start characters or the end of the string.
414 415 416 417 418 419 420 421 422 423
        $bytes = -1; $chars = -1;
        while ($bytes < $strlen - 1 && $chars < $start) {
          $bytes++;
          $c = ord($text[$bytes]);
          if ($c < 0x80 || $c >= 0xC0) {
            $chars++;
          }
        }
      }
      elseif ($start < 0) {
424 425
        // Count all the characters except continuation bytes from the end
        // until we have found abs($start) characters.
426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442
        $start = abs($start);
        $bytes = $strlen; $chars = 0;
        while ($bytes > 0 && $chars < $start) {
          $bytes--;
          $c = ord($text[$bytes]);
          if ($c < 0x80 || $c >= 0xC0) {
            $chars++;
          }
        }
      }
      $istart = $bytes;

      // Find the ending byte offset.
      if ($length === NULL) {
        $iend = $strlen;
      }
      elseif ($length > 0) {
443 444 445
        // Count all the characters except continuation bytes from the starting
        // index until we have found $length characters or reached the end of
        // the string, then backtrace one byte.
446 447 448 449 450 451 452 453 454 455 456 457
        $iend = $istart - 1;
        $chars = -1;
        $last_real = FALSE;
        while ($iend < $strlen - 1 && $chars < $length) {
          $iend++;
          $c = ord($text[$iend]);
          $last_real = FALSE;
          if ($c < 0x80 || $c >= 0xC0) {
            $chars++;
            $last_real = TRUE;
          }
        }
458 459
        // Backtrace one byte if the last character we found was a real
        // character and we don't need it.
460 461 462 463 464
        if ($last_real && $chars >= $length) {
          $iend--;
        }
      }
      elseif ($length < 0) {
465 466
        // Count all the characters except continuation bytes from the end
        // until we have found abs($start) characters, then backtrace one byte.
467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507
        $length = abs($length);
        $iend = $strlen; $chars = 0;
        while ($iend > 0 && $chars < $length) {
          $iend--;
          $c = ord($text[$iend]);
          if ($c < 0x80 || $c >= 0xC0) {
            $chars++;
          }
        }
        // Backtrace one byte if we are not at the beginning of the string.
        if ($iend > 0) {
          $iend--;
        }
      }
      else {
        // $length == 0, return an empty string.
        return '';
      }

      return substr($text, $istart, max(0, $iend - $istart + 1));
    }
  }

  /**
   * Truncates a UTF-8-encoded string safely to a number of characters.
   *
   * @param string $string
   *   The string to truncate.
   * @param int $max_length
   *   An upper limit on the returned string length, including trailing ellipsis
   *   if $add_ellipsis is TRUE.
   * @param bool $wordsafe
   *   If TRUE, attempt to truncate on a word boundary. Word boundaries are
   *   spaces, punctuation, and Unicode characters used as word boundaries in
   *   non-Latin languages; see Unicode::PREG_CLASS_WORD_BOUNDARY for more
   *   information. If a word boundary cannot be found that would make the length
   *   of the returned string fall within length guidelines (see parameters
   *   $max_length and $min_wordsafe_length), word boundaries are ignored.
   * @param bool $add_ellipsis
   *   If TRUE, add '...' to the end of the truncated string (defaults to
   *   FALSE). The string length will still fall within $max_length.
508
   * @param int $min_wordsafe_length
509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546
   *   If $wordsafe is TRUE, the minimum acceptable length for truncation (before
   *   adding an ellipsis, if $add_ellipsis is TRUE). Has no effect if $wordsafe
   *   is FALSE. This can be used to prevent having a very short resulting string
   *   that will not be understandable. For instance, if you are truncating the
   *   string "See myverylongurlexample.com for more information" to a word-safe
   *   return length of 20, the only available word boundary within 20 characters
   *   is after the word "See", which wouldn't leave a very informative string. If
   *   you had set $min_wordsafe_length to 10, though, the function would realise
   *   that "See" alone is too short, and would then just truncate ignoring word
   *   boundaries, giving you "See myverylongurl..." (assuming you had set
   *   $add_ellipses to TRUE).
   *
   * @return string
   *   The truncated string.
   */
  public static function truncate($string, $max_length, $wordsafe = FALSE, $add_ellipsis = FALSE, $min_wordsafe_length = 1) {
    $ellipsis = '';
    $max_length = max($max_length, 0);
    $min_wordsafe_length = max($min_wordsafe_length, 0);

    if (static::strlen($string) <= $max_length) {
      // No truncation needed, so don't add ellipsis, just return.
      return $string;
    }

    if ($add_ellipsis) {
      // Truncate ellipsis in case $max_length is small.
      $ellipsis = static::substr('…', 0, $max_length);
      $max_length -= static::strlen($ellipsis);
      $max_length = max($max_length, 0);
    }

    if ($max_length <= $min_wordsafe_length) {
      // Do not attempt word-safe if lengths are bad.
      $wordsafe = FALSE;
    }

    if ($wordsafe) {
547
      $matches = [];
548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572
      // Find the last word boundary, if there is one within $min_wordsafe_length
      // to $max_length characters. preg_match() is always greedy, so it will
      // find the longest string possible.
      $found = preg_match('/^(.{' . $min_wordsafe_length . ',' . $max_length . '})[' . Unicode::PREG_CLASS_WORD_BOUNDARY . ']/u', $string, $matches);
      if ($found) {
        $string = $matches[1];
      }
      else {
        $string = static::substr($string, 0, $max_length);
      }
    }
    else {
      $string = static::substr($string, 0, $max_length);
    }

    if ($add_ellipsis) {
      // If we're adding an ellipsis, remove any trailing periods.
      $string = rtrim($string, '.');

      $string .= $ellipsis;
    }

    return $string;
  }

573 574 575 576 577 578 579 580 581 582 583 584
  /**
   * Compares UTF-8-encoded strings in a binary safe case-insensitive manner.
   *
   * @param string $str1
   *   The first string.
   * @param string $str2
   *   The second string.
   *
   * @return int
   *   Returns < 0 if $str1 is less than $str2; > 0 if $str1 is greater than
   *   $str2, and 0 if they are equal.
   */
585
  public static function strcasecmp($str1, $str2) {
586
    return strcmp(static::strtoupper($str1), static::strtoupper($str2));
587 588
  }

589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611
  /**
   * Encodes MIME/HTTP headers that contain incorrectly encoded characters.
   *
   * For example, Unicode::mimeHeaderEncode('tést.txt') returns
   * "=?UTF-8?B?dMOpc3QudHh0?=".
   *
   * See http://www.rfc-editor.org/rfc/rfc2047.txt for more information.
   *
   * Notes:
   * - Only encode strings that contain non-ASCII characters.
   * - We progressively cut-off a chunk with self::truncateBytes(). This ensures
   *   each chunk starts and ends on a character boundary.
   * - Using \n as the chunk separator may cause problems on some systems and
   *   may have to be changed to \r\n or \r.
   *
   * @param string $string
   *   The header to encode.
   *
   * @return string
   *   The mime-encoded header.
   */
  public static function mimeHeaderEncode($string) {
    if (preg_match('/[^\x20-\x7E]/', $string)) {
612 613
      // floor((75 - strlen("=?UTF-8?B??=")) * 0.75);
      $chunk_size = 47;
614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663
      $len = strlen($string);
      $output = '';
      while ($len > 0) {
        $chunk = static::truncateBytes($string, $chunk_size);
        $output .= ' =?UTF-8?B?' . base64_encode($chunk) . "?=\n";
        $c = strlen($chunk);
        $string = substr($string, $c);
        $len -= $c;
      }
      return trim($output);
    }
    return $string;
  }

  /**
   * Decodes MIME/HTTP encoded header values.
   *
   * @param string $header
   *   The header to decode.
   *
   * @return string
   *   The mime-decoded header.
   */
  public static function mimeHeaderDecode($header) {
    $callback = function ($matches) {
      $data = ($matches[2] == 'B') ? base64_decode($matches[3]) : str_replace('_', ' ', quoted_printable_decode($matches[3]));
      if (strtolower($matches[1]) != 'utf-8') {
        $data = static::convertToUtf8($data, $matches[1]);
      }
      return $data;
    };
    // First step: encoded chunks followed by other encoded chunks (need to collapse whitespace)
    $header = preg_replace_callback('/=\?([^?]+)\?(Q|B)\?([^?]+|\?(?!=))\?=\s+(?==\?)/', $callback, $header);
    // Second step: remaining chunks (do not collapse whitespace)
    return preg_replace_callback('/=\?([^?]+)\?(Q|B)\?([^?]+|\?(?!=))\?=/', $callback, $header);
  }

  /**
   * Flip U+C0-U+DE to U+E0-U+FD and back. Can be used as preg_replace callback.
   *
   * @param array $matches
   *   An array of matches by preg_replace_callback().
   *
   * @return string
   *   The flipped text.
   */
  public static function caseFlip($matches) {
    return $matches[0][0] . chr(ord($matches[0][1]) ^ 32);
  }

664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697
  /**
   * Checks whether a string is valid UTF-8.
   *
   * All functions designed to filter input should use drupal_validate_utf8
   * to ensure they operate on valid UTF-8 strings to prevent bypass of the
   * filter.
   *
   * When text containing an invalid UTF-8 lead byte (0xC0 - 0xFF) is presented
   * as UTF-8 to Internet Explorer 6, the program may misinterpret subsequent
   * bytes. When these subsequent bytes are HTML control characters such as
   * quotes or angle brackets, parts of the text that were deemed safe by filters
   * end up in locations that are potentially unsafe; An onerror attribute that
   * is outside of a tag, and thus deemed safe by a filter, can be interpreted
   * by the browser as if it were inside the tag.
   *
   * The function does not return FALSE for strings containing character codes
   * above U+10FFFF, even though these are prohibited by RFC 3629.
   *
   * @param string $text
   *   The text to check.
   *
   * @return bool
   *   TRUE if the text is valid UTF-8, FALSE if not.
   */
  public static function validateUtf8($text) {
    if (strlen($text) == 0) {
      return TRUE;
    }
    // With the PCRE_UTF8 modifier 'u', preg_match() fails silently on strings
    // containing invalid UTF-8 byte sequences. It does not reject character
    // codes above U+10FFFF (represented by 4 or more octets), though.
    return (preg_match('/^./us', $text) == 1);
  }

698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726
  /**
   * Finds the position of the first occurrence of a string in another string.
   *
   * @param string $haystack
   *   The string to search in.
   * @param string $needle
   *   The string to find in $haystack.
   * @param int $offset
   *   If specified, start the search at this number of characters from the
   *   beginning (default 0).
   *
   * @return int|false
   *   The position where $needle occurs in $haystack, always relative to the
   *   beginning (independent of $offset), or FALSE if not found. Note that
   *   a return value of 0 is not the same as FALSE.
   */
  public static function strpos($haystack, $needle, $offset = 0) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return mb_strpos($haystack, $needle, $offset);
    }
    else {
      // Remove Unicode continuation characters, to be compatible with
      // Unicode::strlen() and Unicode::substr().
      $haystack = preg_replace("/[\x80-\xBF]/", '', $haystack);
      $needle = preg_replace("/[\x80-\xBF]/", '', $needle);
      return strpos($haystack, $needle, $offset);
    }
  }

727
}