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<?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.
*
* A big part of this class acts as a wrapper over the Typo3 charset library,
* really a cool group of utilities to handle texts and encoding conversion.
*
* Take a look to its own copyright and license details.
*
* IMPORTANT Note: Typo3 libraries always expect lowercase charsets to use 100%
* its capabilities so, don't forget to make the conversion
* from every wrapper function!
*
* @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[] Array of strings representing Unicode non-characters
*/
protected static $noncharacters;
/**
* Return t3lib helper class, which is used for conversion between charsets
*
* @param bool $reset
* @return t3lib_cs
*/
protected static function typo3($reset = false) {
static $typo3cs = null;
if ($reset) {
$typo3cs = null;
return null;
}
if (isset($typo3cs)) {
return $typo3cs;
}
global $CFG;
// Required files
require_once($CFG->libdir.'/typo3/class.t3lib_cs.php');
require_once($CFG->libdir.'/typo3/class.t3lib_div.php');
require_once($CFG->libdir.'/typo3/interface.t3lib_singleton.php');
require_once($CFG->libdir.'/typo3/class.t3lib_l10n_locales.php');
// do not use mbstring or recode because it may return invalid results in some corner cases
$GLOBALS['TYPO3_CONF_VARS']['SYS']['t3lib_cs_convMethod'] = 'iconv';
$GLOBALS['TYPO3_CONF_VARS']['SYS']['t3lib_cs_utils'] = 'iconv';
// Tell Typo3 we are curl enabled always (mandatory since 2.0)
$GLOBALS['TYPO3_CONF_VARS']['SYS']['curlUse'] = '1';
// And this directory must exist to allow Typo to cache conversion
// tables when using internal functions
make_temp_directory('typo3temp/cs');
// Make sure typo is using our dir permissions
$GLOBALS['TYPO3_CONF_VARS']['BE']['folderCreateMask'] = decoct($CFG->directorypermissions);
// Default mask for Typo
$GLOBALS['TYPO3_CONF_VARS']['BE']['fileCreateMask'] = decoct($CFG->filepermissions);
// This full path constants must be defined too, transforming backslashes
// to forward slashed because Typo3 requires it.
if (!defined('PATH_t3lib')) {
define('PATH_t3lib', str_replace('\\','/',$CFG->libdir.'/typo3/'));
define('PATH_typo3', str_replace('\\','/',$CFG->libdir.'/typo3/'));
define('PATH_site', str_replace('\\','/',$CFG->tempdir.'/'));
define('TYPO3_OS', stristr(PHP_OS,'win')&&!stristr(PHP_OS,'darwin')?'WIN':'');
}
$typo3cs = new t3lib_cs();
return $typo3cs;
}
/**
* Reset internal textlib caches.
* @static
*/
public static function reset_caches() {
self::typo3(true);
}
/**
* 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);
// shortcuts so that we do not have to load typo3 on every page
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 ($charset === 'gb18030') {
return 'gb18030';
}
// fallback to typo3
return self::typo3()->parse_charset($charset);
}
/**
* Converts the text between different encodings. It uses iconv extension with //TRANSLIT parameter,
* falls back to typo3. 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 from Typo3 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);
$result = self::typo3()->conv((string)$text, $fromCS, $toCS);
error_reporting($oldlevel);
}
return $result;
}
/**
* Multibyte safe substr() function, uses mbstring or iconv for UTF-8, falls back to typo3.
*
* @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);
if ($charset === 'utf-8') {
if (function_exists('mb_substr')) {
// this is much faster than iconv - see MDL-31142
if ($len === null) {
$oldcharset = mb_internal_encoding();
mb_internal_encoding('UTF-8');
$result = mb_substr($text, $start);
mb_internal_encoding($oldcharset);
return $result;
} else {
return mb_substr($text, $start, $len, 'UTF-8');
}
} else {
if ($len === null) {
$len = iconv_strlen($text, 'UTF-8');
}
return iconv_substr($text, $start, $len, 'UTF-8');
}
}
$oldlevel = error_reporting(E_PARSE);
if ($len === null) {
$result = self::typo3()->substr($charset, (string)$text, $start);
} else {
$result = self::typo3()->substr($charset, (string)$text, $start, $len);
}
error_reporting($oldlevel);
return $result;
}
/**
* Truncates a string to no more than a certain number of bytes in a multi-byte safe manner.
* UTF-8 only!
*
* Many of the other charsets we test for (like ISO-2022-JP and EUC-JP) are not supported
* by typo3, and will give invalid results, so we are supporting 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, $bytes) {
if (function_exists('mb_strcut')) {
return mb_strcut($string, 0, $bytes, 'UTF-8');
}
$oldlevel = error_reporting(E_PARSE);
$result = self::typo3()->strtrunc('utf-8', $string, $bytes);
error_reporting($oldlevel);
return $result;
}
/**
* 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, $part = false) {
if (function_exists('mb_strrchr')) {
return mb_strrchr($haystack, $needle, $part, 'UTF-8');
}
$pos = self::strrpos($haystack, $needle);
if ($pos === false) {
return false;
}
$length = null;
if ($part) {
$length = $pos;
$pos = 0;
}
return self::substr($haystack, $pos, $length, 'utf-8');
}
/**
* Multibyte safe strlen() function, uses mbstring or iconv for UTF-8, falls back to typo3.
*
* @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 ($charset === 'utf-8') {
if (function_exists('mb_strlen')) {
return mb_strlen($text, 'UTF-8');
} else {
return iconv_strlen($text, 'UTF-8');
}
}
$oldlevel = error_reporting(E_PARSE);
$result = self::typo3()->strlen($charset, (string)$text);
error_reporting($oldlevel);
return $result;
}
/**
* Multibyte safe strtolower() function, uses mbstring, falls back to typo3.
*
* @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);
if ($charset === 'utf-8' and function_exists('mb_strtolower')) {
return mb_strtolower($text, 'UTF-8');
}
$oldlevel = error_reporting(E_PARSE);
$result = self::typo3()->conv_case($charset, (string)$text, 'toLower');
error_reporting($oldlevel);
return $result;
}
/**
* Multibyte safe strtoupper() function, uses mbstring, falls back to typo3.
*
* @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);
if ($charset === 'utf-8' and function_exists('mb_strtoupper')) {
return mb_strtoupper($text, 'UTF-8');
}
$oldlevel = error_reporting(E_PARSE);
$result = self::typo3()->conv_case($charset, (string)$text, 'toUpper');
error_reporting($oldlevel);
return $result;
}
/**
* Find the position of the first occurrence of a substring in a string.
* UTF-8 ONLY safe strpos(), uses mbstring, falls back to iconv.
*
* @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, $offset=0) {
if (function_exists('mb_strpos')) {
return mb_strpos($haystack, $needle, $offset, 'UTF-8');
} else {
return iconv_strpos($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, falls back to iconv.
*
* @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, $needle) {
if (function_exists('mb_strrpos')) {
return mb_strrpos($haystack, $needle, null, 'UTF-8');
} else {
return iconv_strrpos($haystack, $needle, '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.
*
* @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);
$result = self::typo3()->specCharsToASCII($charset, (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);
}
// Avoid some notices from Typo3 code
$oldlevel = error_reporting(E_PARSE);
$result = self::typo3()->utf8_to_entities((string)$str);
error_reporting($oldlevel);
if ($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) {
$bom = "\xef\xbb\xbf";
if (strpos($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;
foreach (self::typo3()->synonyms 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 $text;
}
if (function_exists('mb_convert_case')) {
return mb_convert_case($text, MB_CASE_TITLE, 'UTF-8');
}
$text = self::strtolower($text);
$words = explode(' ', $text);
foreach ($words as $i=>$word) {
$length = self::strlen($word);
if (!$length) {
continue;
} else if ($length == 1) {
$words[$i] = self::strtoupper($word);
} else {
$letter = self::substr($word, 0, 1);
$letter = self::strtoupper($letter);
$rest = self::substr($word, 1);
$words[$i] = $letter.$rest;
}
}
return implode(' ', $words);
}
}