| decode_entities | Decodes all HTML entities (including numerical ones) to regular UTF-8 bytes. |
| drupal_convert_to_utf8 | Converts data to UTF-8. |
| drupal_strlen | Counts the number of characters in a UTF-8 string. |
| drupal_strtolower | Lowercase a UTF-8 string. |
| drupal_strtoupper | Uppercase a UTF-8 string. |
| drupal_substr | Cuts off a piece of a string based on character indices and counts. |
| drupal_truncate_bytes | Truncates a UTF-8-encoded string safely to a number of bytes. |
| drupal_ucfirst | Capitalizes the first letter of a UTF-8 string. |
| drupal_xml_parser_create | Prepares a new XML parser. |
| mime_header_decode | Decodes MIME/HTTP encoded header values. |
| mime_header_encode | Encodes MIME/HTTP header values that contain incorrectly encoded characters. |
| truncate_utf8 | Truncates a UTF-8-encoded string safely to a number of characters. |
| unicode_check | Wrapper around _unicode_check(). |
| unicode_requirements | Returns Unicode library status and errors. |
| _mime_header_decode | Decodes encoded header data passed from mime_header_decode(). |
| _unicode_caseflip | Flips U+C0-U+DE to U+E0-U+FD and back. |
| _unicode_check | Perform checks about Unicode support in PHP, and set the right settings if needed. |