public static function Unicode::truncateBytes in Drupal 8

Same name and namespace in other branches

1. 9 core/lib/Drupal/Component/Utility/Unicode.php \Drupal\Component\Utility\Unicode::truncateBytes()

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.

Parameters

string $string: The string to truncate.

int $len: An upper limit on the returned string length.

Return value

string The truncated string.

3 calls to Unicode::truncateBytes()

Connection::query in core/lib/Drupal/Core/Database/Driver/mysql/Connection.php

Executes a query string against the database.

Unicode::mimeHeaderEncode in core/lib/Drupal/Component/Utility/Unicode.php

Encodes MIME/HTTP headers that contain incorrectly encoded characters.

UnicodeTest::testTruncateBytes in core/tests/Drupal/Tests/Component/Utility/UnicodeTest.php

Tests multibyte truncate bytes.

File

core/lib/Drupal/Component/Utility/Unicode.php, line 238

Class

Unicode

Provides Unicode-related conversions and operations.

Namespace

Drupal\Component\Utility

Code

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.
  // @todo Make the code more readable in https://www.drupal.org/node/2911497.
  while (--$len >= 0 && ord($string[$len]) >= 0x80 && ord($string[$len]) < 0xc0) {
  }
  return substr($string, 0, $len);
}