/lib/classes/text.php
PHP | 672 lines | 348 code | 62 blank | 262 comment | 62 complexity | 837c772089ebdef82f56572305b04954 MD5 | raw file
Possible License(s): BSD-3-Clause, MIT, GPL-3.0, Apache-2.0, LGPL-2.1
- <?php
- // This file is part of Moodle - http://moodle.org/
- //
- // Moodle is free software: you can redistribute it and/or modify
- // it under the terms of the GNU General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // Moodle is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU General Public License for more details.
- //
- // You should have received a copy of the GNU General Public License
- // along with Moodle. If not, see <http://www.gnu.org/licenses/>.
- /**
- * Defines string apis
- *
- * @package core
- * @copyright (C) 2001-3001 Eloy Lafuente (stronk7) {@link http://contiento.com}
- * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
- defined('MOODLE_INTERNAL') || die();
- /**
- * defines string api's for manipulating strings
- *
- * This class is used to manipulate strings under Moodle 1.6 an later. As
- * utf-8 text become mandatory a pool of safe functions under this encoding
- * become necessary. The name of the methods is exactly the
- * same than their PHP originals.
- *
- * This class was previously based on Typo3 which has now been removed and uses
- * native functions now.
- *
- * @package core
- * @category string
- * @copyright 1999 onwards Martin Dougiamas {@link http://moodle.com}
- * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
- class core_text {
- /** @var string Byte order mark for UTF-8 */
- const UTF8_BOM = "\xef\xbb\xbf";
- /**
- * @var string[] Array of strings representing Unicode non-characters
- */
- protected static $noncharacters;
- /**
- * Check whether the charset is supported by mbstring.
- * @param string $charset Normalised charset
- * @return bool
- */
- public static function is_charset_supported(string $charset): bool {
- static $cache = null;
- if (!$cache) {
- $cache = array_flip(array_map('strtolower', mb_list_encodings()));
- }
- if (isset($cache[strtolower($charset)])) {
- return true;
- }
- // We haven't found the charset, check if mb has aliases for the charset.
- try {
- return mb_encoding_aliases($charset) !== false;
- } catch (Throwable $e) {
- // A ValueError will be thrown if unsupported.
- }
- return false;
- }
- /**
- * Reset internal textlib caches.
- * @static
- * @deprecated since Moodle 4.0. See MDL-53544.
- * @todo To be removed in Moodle 4.4 - MDL-71748
- */
- public static function reset_caches() {
- debugging("reset_caches() is deprecated. Typo3 has been removed and caches aren't used anymore.", DEBUG_DEVELOPER);
- }
- /**
- * Standardise charset name
- *
- * Please note it does not mean the returned charset is actually supported.
- *
- * @static
- * @param string $charset raw charset name
- * @return string normalised lowercase charset name
- */
- public static function parse_charset($charset) {
- $charset = strtolower($charset);
- if ($charset === 'utf8' or $charset === 'utf-8') {
- return 'utf-8';
- }
- if (preg_match('/^(cp|win|windows)-?(12[0-9]{2})$/', $charset, $matches)) {
- return 'windows-'.$matches[2];
- }
- if (preg_match('/^iso-8859-[0-9]+$/', $charset, $matches)) {
- return $charset;
- }
- if ($charset === 'euc-jp') {
- return 'euc-jp';
- }
- if ($charset === 'iso-2022-jp') {
- return 'iso-2022-jp';
- }
- if ($charset === 'shift-jis' or $charset === 'shift_jis') {
- return 'shift_jis';
- }
- if ($charset === 'gb2312') {
- return 'gb2312';
- }
- if ($charset === 'gb18030') {
- return 'gb18030';
- }
- if ($charset === 'ms-ansi') {
- return 'windows-1252';
- }
- // We have reached this stage and haven't matched with anything. Return the original.
- return $charset;
- }
- /**
- * Converts the text between different encodings. It uses iconv extension with //TRANSLIT parameter.
- * If both source and target are utf-8 it tries to fix invalid characters only.
- *
- * @param string $text
- * @param string $fromCS source encoding
- * @param string $toCS result encoding
- * @return string|bool converted string or false on error
- */
- public static function convert($text, $fromCS, $toCS='utf-8') {
- $fromCS = self::parse_charset($fromCS);
- $toCS = self::parse_charset($toCS);
- $text = (string)$text; // we can work only with strings
- if ($text === '') {
- return '';
- }
- if ($fromCS === 'utf-8') {
- $text = fix_utf8($text);
- if ($toCS === 'utf-8') {
- return $text;
- }
- }
- if ($toCS === 'ascii') {
- // Try to normalize the conversion a bit.
- $text = self::specialtoascii($text, $fromCS);
- }
- // Prevent any error notices, do not use //IGNORE so that we get
- // consistent result if iconv fails.
- $result = @iconv($fromCS, $toCS.'//TRANSLIT', $text);
- if ($result === false or $result === '') {
- // Note: iconv is prone to return empty string when invalid char encountered, or false if encoding unsupported.
- $oldlevel = error_reporting(E_PARSE);
- error_reporting($oldlevel);
- }
- return $result;
- }
- /**
- * Multibyte safe substr() function, uses mbstring or iconv
- *
- * @param string $text string to truncate
- * @param int $start negative value means from end
- * @param int $len maximum length of characters beginning from start
- * @param string $charset encoding of the text
- * @return string portion of string specified by the $start and $len
- */
- public static function substr($text, $start, $len=null, $charset='utf-8') {
- $charset = self::parse_charset($charset);
- // Check whether the charset is supported by mbstring. CP1250 is not supported. Fall back to iconv.
- if (self::is_charset_supported($charset)) {
- $result = mb_substr($text, $start, $len, $charset);
- } else {
- $result = iconv_substr($text, $start, $len, $charset);
- }
- return $result;
- }
- /**
- * Truncates a string to no more than a certain number of bytes in a multi-byte safe manner.
- * UTF-8 only!
- *
- * @param string $string String to truncate
- * @param int $bytes Maximum length of bytes in the result
- * @return string Portion of string specified by $bytes
- * @since Moodle 3.1
- */
- public static function str_max_bytes($string, $bytes) {
- return mb_strcut($string, 0, $bytes, 'UTF-8');
- }
- /**
- * Finds the last occurrence of a character in a string within another.
- * UTF-8 ONLY safe mb_strrchr().
- *
- * @param string $haystack The string from which to get the last occurrence of needle.
- * @param string $needle The string to find in haystack.
- * @param boolean $part If true, returns the portion before needle, else return the portion after (including needle).
- * @return string|false False when not found.
- * @since Moodle 2.4.6, 2.5.2, 2.6
- */
- public static function strrchr($haystack, $needle, $part = false) {
- return mb_strrchr($haystack, $needle, $part, 'UTF-8');
- }
- /**
- * Multibyte safe strlen() function, uses mbstring or iconv
- *
- * @param string $text input string
- * @param string $charset encoding of the text
- * @return int number of characters
- */
- public static function strlen($text, $charset='utf-8') {
- $charset = self::parse_charset($charset);
- if (self::is_charset_supported($charset)) {
- return mb_strlen($text, $charset);
- }
- return iconv_strlen($text, $charset);
- }
- /**
- * Multibyte safe strtolower() function, uses mbstring.
- *
- * @param string $text input string
- * @param string $charset encoding of the text (may not work for all encodings)
- * @return string lower case text
- */
- public static function strtolower($text, $charset='utf-8') {
- $charset = self::parse_charset($charset);
- // Confirm mbstring can handle the charset.
- if (self::is_charset_supported($charset)) {
- return mb_strtolower($text, $charset);
- }
- // The mbstring extension cannot handle the charset. Convert to UTF-8.
- $convertedtext = self::convert($text, $charset, 'utf-8');
- $result = mb_strtolower($convertedtext);
- $result = self::convert($result, 'utf-8', $charset);
- return $result;
- }
- /**
- * Multibyte safe strtoupper() function, uses mbstring.
- *
- * @param string $text input string
- * @param string $charset encoding of the text (may not work for all encodings)
- * @return string upper case text
- */
- public static function strtoupper($text, $charset='utf-8') {
- $charset = self::parse_charset($charset);
- // Confirm mbstring can handle the charset.
- if (self::is_charset_supported($charset)) {
- return mb_strtoupper($text, $charset);
- }
- // The mbstring extension cannot handle the charset. Convert to UTF-8.
- $convertedtext = self::convert($text, $charset, 'utf-8');
- $result = mb_strtoupper($convertedtext);
- $result = self::convert($result, 'utf-8', $charset);
- return $result;
- }
- /**
- * Find the position of the first occurrence of a substring in a string.
- * UTF-8 ONLY safe strpos(), uses mbstring
- *
- * @param string $haystack the string to search in
- * @param string $needle one or more charachters to search for
- * @param int $offset offset from begining of string
- * @return int the numeric position of the first occurrence of needle in haystack.
- */
- public static function strpos($haystack, $needle, $offset=0) {
- return mb_strpos($haystack, $needle, $offset, 'UTF-8');
- }
- /**
- * Find the position of the last occurrence of a substring in a string
- * UTF-8 ONLY safe strrpos(), uses mbstring
- *
- * @param string $haystack the string to search in
- * @param string $needle one or more charachters to search for
- * @return int the numeric position of the last occurrence of needle in haystack
- */
- public static function strrpos($haystack, $needle) {
- return mb_strrpos($haystack, $needle, null, 'UTF-8');
- }
- /**
- * Reverse UTF-8 multibytes character sets (used for RTL languages)
- * (We only do this because there is no mb_strrev or iconv_strrev)
- *
- * @param string $str the multibyte string to reverse
- * @return string the reversed multi byte string
- */
- public static function strrev($str) {
- preg_match_all('/./us', $str, $ar);
- return join('', array_reverse($ar[0]));
- }
- /**
- * Try to convert upper unicode characters to plain ascii,
- * the returned string may contain unconverted unicode characters.
- *
- * With the removal of typo3, iconv conversions was found to be the best alternative to Typo3's function.
- * However using the standard iconv call
- * iconv($charset, 'ASCII//TRANSLIT//IGNORE', (string) $text);
- * resulted in invalid strings with special character from Russian/Japanese. To solve this, the transliterator was
- * used but this resulted in empty strings for certain strings in our test. It was decided to use a combo of the 2
- * to cover all our bases. Refer MDL-53544 for further information.
- *
- * @param string $text input string
- * @param string $charset encoding of the text
- * @return string converted ascii string
- */
- public static function specialtoascii($text, $charset='utf-8') {
- $charset = self::parse_charset($charset);
- $oldlevel = error_reporting(E_PARSE);
- if ($charset == 'utf-8') {
- $text = transliterator_transliterate('Any-Latin; Latin-ASCII', (string) $text);
- }
- $result = iconv($charset, 'ASCII//TRANSLIT//IGNORE', (string) $text);
- error_reporting($oldlevel);
- return $result;
- }
- /**
- * Generate a correct base64 encoded header to be used in MIME mail messages.
- * This function seems to be 100% compliant with RFC1342. Credits go to:
- * paravoid (http://www.php.net/manual/en/function.mb-encode-mimeheader.php#60283).
- *
- * @param string $text input string
- * @param string $charset encoding of the text
- * @return string base64 encoded header
- */
- public static function encode_mimeheader($text, $charset='utf-8') {
- if (empty($text)) {
- return (string)$text;
- }
- // Normalize charset
- $charset = self::parse_charset($charset);
- // If the text is pure ASCII, we don't need to encode it
- if (self::convert($text, $charset, 'ascii') == $text) {
- return $text;
- }
- // Although RFC says that line feed should be \r\n, it seems that
- // some mailers double convert \r, so we are going to use \n alone
- $linefeed="\n";
- // Define start and end of every chunk
- $start = "=?$charset?B?";
- $end = "?=";
- // Accumulate results
- $encoded = '';
- // Max line length is 75 (including start and end)
- $length = 75 - strlen($start) - strlen($end);
- // Multi-byte ratio
- $multilength = self::strlen($text, $charset);
- // Detect if strlen and friends supported
- if ($multilength === false) {
- if ($charset == 'GB18030' or $charset == 'gb18030') {
- while (strlen($text)) {
- // try to encode first 22 chars - we expect most chars are two bytes long
- if (preg_match('/^(([\x00-\x7f])|([\x81-\xfe][\x40-\x7e])|([\x81-\xfe][\x80-\xfe])|([\x81-\xfe][\x30-\x39]..)){1,22}/m', $text, $matches)) {
- $chunk = $matches[0];
- $encchunk = base64_encode($chunk);
- if (strlen($encchunk) > $length) {
- // find first 11 chars - each char in 4 bytes - worst case scenario
- preg_match('/^(([\x00-\x7f])|([\x81-\xfe][\x40-\x7e])|([\x81-\xfe][\x80-\xfe])|([\x81-\xfe][\x30-\x39]..)){1,11}/m', $text, $matches);
- $chunk = $matches[0];
- $encchunk = base64_encode($chunk);
- }
- $text = substr($text, strlen($chunk));
- $encoded .= ' '.$start.$encchunk.$end.$linefeed;
- } else {
- break;
- }
- }
- $encoded = trim($encoded);
- return $encoded;
- } else {
- return false;
- }
- }
- $ratio = $multilength / strlen($text);
- // Base64 ratio
- $magic = $avglength = floor(3 * $length * $ratio / 4);
- // basic infinite loop protection
- $maxiterations = strlen($text)*2;
- $iteration = 0;
- // Iterate over the string in magic chunks
- for ($i=0; $i <= $multilength; $i+=$magic) {
- if ($iteration++ > $maxiterations) {
- return false; // probably infinite loop
- }
- $magic = $avglength;
- $offset = 0;
- // Ensure the chunk fits in length, reducing magic if necessary
- do {
- $magic -= $offset;
- $chunk = self::substr($text, $i, $magic, $charset);
- $chunk = base64_encode($chunk);
- $offset++;
- } while (strlen($chunk) > $length);
- // This chunk doesn't break any multi-byte char. Use it.
- if ($chunk)
- $encoded .= ' '.$start.$chunk.$end.$linefeed;
- }
- // Strip the first space and the last linefeed
- $encoded = substr($encoded, 1, -strlen($linefeed));
- return $encoded;
- }
- /**
- * Returns HTML entity transliteration table.
- * @return array with (html entity => utf-8) elements
- */
- protected static function get_entities_table() {
- static $trans_tbl = null;
- // Generate/create $trans_tbl
- if (!isset($trans_tbl)) {
- if (version_compare(phpversion(), '5.3.4') < 0) {
- $trans_tbl = array();
- foreach (get_html_translation_table(HTML_ENTITIES) as $val=>$key) {
- $trans_tbl[$key] = self::convert($val, 'ISO-8859-1', 'utf-8');
- }
- } else if (version_compare(phpversion(), '5.4.0') < 0) {
- $trans_tbl = get_html_translation_table(HTML_ENTITIES, ENT_COMPAT, 'UTF-8');
- $trans_tbl = array_flip($trans_tbl);
- } else {
- $trans_tbl = get_html_translation_table(HTML_ENTITIES, ENT_COMPAT | ENT_HTML401, 'UTF-8');
- $trans_tbl = array_flip($trans_tbl);
- }
- }
- return $trans_tbl;
- }
- /**
- * Converts all the numeric entities &#nnnn; or &#xnnn; to UTF-8
- * Original from laurynas dot butkus at gmail at:
- * http://php.net/manual/en/function.html-entity-decode.php#75153
- * with some custom mods to provide more functionality
- *
- * @param string $str input string
- * @param boolean $htmlent convert also html entities (defaults to true)
- * @return string encoded UTF-8 string
- */
- public static function entities_to_utf8($str, $htmlent=true) {
- static $callback1 = null ;
- static $callback2 = null ;
- if (!$callback1 or !$callback2) {
- $callback1 = function($matches) {
- return core_text::code2utf8(hexdec($matches[1]));
- };
- $callback2 = function($matches) {
- return core_text::code2utf8($matches[1]);
- };
- }
- $result = (string)$str;
- $result = preg_replace_callback('/&#x([0-9a-f]+);/i', $callback1, $result);
- $result = preg_replace_callback('/&#([0-9]+);/', $callback2, $result);
- // Replace literal entities (if desired)
- if ($htmlent) {
- $trans_tbl = self::get_entities_table();
- // It should be safe to search for ascii strings and replace them with utf-8 here.
- $result = strtr($result, $trans_tbl);
- }
- // Return utf8-ised string
- return $result;
- }
- /**
- * Converts all Unicode chars > 127 to numeric entities &#nnnn; or &#xnnn;.
- *
- * @param string $str input string
- * @param boolean $dec output decadic only number entities
- * @param boolean $nonnum remove all non-numeric entities
- * @return string converted string
- */
- public static function utf8_to_entities($str, $dec=false, $nonnum=false) {
- static $callback = null ;
- if ($nonnum) {
- $str = self::entities_to_utf8($str, true);
- }
- $result = mb_strtolower(mb_encode_numericentity($str, [0xa0, 0xffff, 0, 0xffff], 'UTF-8', true));
- // We cannot use the decimal equivalent of the above call due to the unit test and our allowance for
- // entities to be entered within the provided $str. Refer to the correspond unit test for examples.
- if ($dec) {
- if (!$callback) {
- $callback = function($matches) {
- return '&#' . hexdec($matches[1]) . ';';
- };
- }
- $result = preg_replace_callback('/&#x([0-9a-f]+);/i', $callback, $result);
- }
- return $result;
- }
- /**
- * Removes the BOM from unicode string {@link http://unicode.org/faq/utf_bom.html}
- *
- * @param string $str input string
- * @return string
- */
- public static function trim_utf8_bom($str) {
- $bom = self::UTF8_BOM;
- if (strpos($str, $bom) === 0) {
- return substr($str, strlen($bom));
- }
- return $str;
- }
- /**
- * There are a number of Unicode non-characters including the byte-order mark (which may appear
- * multiple times in a string) and also other ranges. These can cause problems for some
- * processing.
- *
- * This function removes the characters using string replace, so that the rest of the string
- * remains unchanged.
- *
- * @param string $value Input string
- * @return string Cleaned string value
- * @since Moodle 3.5
- */
- public static function remove_unicode_non_characters($value) {
- // Set up list of all Unicode non-characters for fast replacing.
- if (!self::$noncharacters) {
- self::$noncharacters = [];
- // This list of characters is based on the Unicode standard. It includes the last two
- // characters of each code planes 0-16 inclusive...
- for ($plane = 0; $plane <= 16; $plane++) {
- $base = ($plane === 0 ? '' : dechex($plane));
- self::$noncharacters[] = html_entity_decode('&#x' . $base . 'fffe;');
- self::$noncharacters[] = html_entity_decode('&#x' . $base . 'ffff;');
- }
- // ...And the character range U+FDD0 to U+FDEF.
- for ($char = 0xfdd0; $char <= 0xfdef; $char++) {
- self::$noncharacters[] = html_entity_decode('&#x' . dechex($char) . ';');
- }
- }
- // Do character replacement.
- return str_replace(self::$noncharacters, '', $value);
- }
- /**
- * Returns encoding options for select boxes, utf-8 and platform encoding first
- *
- * @return array encodings
- */
- public static function get_encodings() {
- $encodings = array();
- $encodings['UTF-8'] = 'UTF-8';
- $winenc = strtoupper(get_string('localewincharset', 'langconfig'));
- if ($winenc != '') {
- $encodings[$winenc] = $winenc;
- }
- $nixenc = strtoupper(get_string('oldcharset', 'langconfig'));
- $encodings[$nixenc] = $nixenc;
- $listedencodings = mb_list_encodings();
- foreach ($listedencodings as $enc) {
- $enc = strtoupper($enc);
- $encodings[$enc] = $enc;
- }
- return $encodings;
- }
- /**
- * Returns the utf8 string corresponding to the unicode value
- * (from php.net, courtesy - romans@void.lv)
- *
- * @param int $num one unicode value
- * @return string the UTF-8 char corresponding to the unicode value
- */
- public static function code2utf8($num) {
- if ($num < 128) {
- return chr($num);
- }
- if ($num < 2048) {
- return chr(($num >> 6) + 192) . chr(($num & 63) + 128);
- }
- if ($num < 65536) {
- return chr(($num >> 12) + 224) . chr((($num >> 6) & 63) + 128) . chr(($num & 63) + 128);
- }
- if ($num < 2097152) {
- return chr(($num >> 18) + 240) . chr((($num >> 12) & 63) + 128) . chr((($num >> 6) & 63) + 128) . chr(($num & 63) + 128);
- }
- return '';
- }
- /**
- * Returns the code of the given UTF-8 character
- *
- * @param string $utf8char one UTF-8 character
- * @return int the code of the given character
- */
- public static function utf8ord($utf8char) {
- if ($utf8char == '') {
- return 0;
- }
- $ord0 = ord($utf8char[0]);
- if ($ord0 >= 0 && $ord0 <= 127) {
- return $ord0;
- }
- $ord1 = ord($utf8char[1]);
- if ($ord0 >= 192 && $ord0 <= 223) {
- return ($ord0 - 192) * 64 + ($ord1 - 128);
- }
- $ord2 = ord($utf8char[2]);
- if ($ord0 >= 224 && $ord0 <= 239) {
- return ($ord0 - 224) * 4096 + ($ord1 - 128) * 64 + ($ord2 - 128);
- }
- $ord3 = ord($utf8char[3]);
- if ($ord0 >= 240 && $ord0 <= 247) {
- return ($ord0 - 240) * 262144 + ($ord1 - 128 )* 4096 + ($ord2 - 128) * 64 + ($ord3 - 128);
- }
- return false;
- }
- /**
- * Makes first letter of each word capital - words must be separated by spaces.
- * Use with care, this function does not work properly in many locales!!!
- *
- * @param string $text input string
- * @return string
- */
- public static function strtotitle($text) {
- if (empty($text)) {
- return $text;
- }
- return mb_convert_case($text, MB_CASE_TITLE, 'UTF-8');
- }
- }