aj
/
chamilo-lms2


			
				
					
						
						
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986
							<?php
/* For licensing terms, see /license.txt */

/**
 * This is the text library for Chamilo.
 * It is loaded during the global initialization,
 * so the functions below are available everywhere.
 *
 * @package chamilo.library
 */
define('EXERCISE_NUMBER_OF_DECIMALS', 2);

/* XML processing functions */

// A regular expression for accessing declared encoding within xml-formatted text.
// Published by Steve Minutillo,
// http://minutillo.com/steve/weblog/2004/6/17/php-xml-and-character-encodings-a-tale-of-sadness-rage-and-data-loss/
define('_PCRE_XML_ENCODING', '/<\?xml.*encoding=[\'"](.*?)[\'"].*\?>/m');

/**
 * This function strips all html-tags found in the input string and outputs a pure text.
 * Mostly, the function is to be used before language or encoding detection of the input string.
 *
 * @param string $string the input string with html-tags to be converted to plain text
 *
 * @return string the returned plain text as a result
 */
function api_html_to_text($string)
{
    // These purifications have been found experimentally, for nice looking output.
    $string = preg_replace('/<br[^>]*>/i', "\n", $string);
    $string = preg_replace('/<\/?(div|p|h[1-6]|table|ol|ul|blockquote)[^>]*>/i', "\n", $string);
    $string = preg_replace('/<\/(tr|li)[^>]*>/i', "\n", $string);
    $string = preg_replace('/<\/(td|th)[^>]*>/i', "\t", $string);

    $string = strip_tags($string);

    // Line endings unification and cleaning.
    $string = str_replace(["\r\n", "\n\r", "\r"], "\n", $string);
    $string = preg_replace('/\s*\n/', "\n", $string);
    $string = preg_replace('/\n+/', "\n", $string);

    return trim($string);
}

/**
 * Detects encoding of html-formatted text.
 *
 * @param string $string the input html-formatted text
 *
 * @return string returns the detected encoding
 */
function api_detect_encoding_html($string)
{
    if (@preg_match('/<head.*(<meta[^>]*content=[^>]*>).*<\/head>/si', $string, $matches)) {
        if (@preg_match('/<meta[^>]*charset=(.*)["\';][^>]*>/si', $matches[1], $matches)) {
            return api_refine_encoding_id(trim($matches[1]));
        }
    }

    return api_detect_encoding(api_html_to_text($string));
}

/**
 * Converts the text of a html-document to a given encoding, the meta-tag is changed accordingly.
 *
 * @param string $string the input full-html document
 * @param string                        the new encoding value to be set
 */
function api_set_encoding_html(&$string, $encoding)
{
    $old_encoding = api_detect_encoding_html($string);
    if (@preg_match('/(.*<head.*)(<meta[^>]*content=[^>]*>)(.*<\/head>.*)/si', $string, $matches)) {
        $meta = $matches[2];
        if (@preg_match("/(<meta[^>]*charset=)(.*)([\"';][^>]*>)/si", $meta, $matches1)) {
            $meta = $matches1[1].$encoding.$matches1[3];
            $string = $matches[1].$meta.$matches[3];
        } else {
            $string = $matches[1].'<meta http-equiv="Content-Type" content="text/html; charset='.$encoding.'"/>'.$matches[3];
        }
    } else {
        $count = 1;
        if (strpos('</head>', strtolower($string)) !== false) {
            $string = str_ireplace(
                '</head>',
                '<meta http-equiv="Content-Type" content="text/html; charset='.$encoding.'"/></head>',
                $string,
                $count
            );
        } else {
            $string = str_ireplace(
                '<body>',
                '<head><meta http-equiv="Content-Type" content="text/html; charset='.$encoding.'"/></head><body>',
                $string,
                $count
            );
        }
    }
    $string = api_convert_encoding($string, $encoding, $old_encoding);
}

/**
 * Returns the title of a html document.
 *
 * @param string $string          the contents of the input document
 * @param string $output_encoding The encoding of the retrieved title.
 *                                If the value is not set, the system encoding is assumed.
 * @param string $input_encoding  The encoding of the input document. If the value is not set, it is detected.
 *
 * @return string the retrieved title, html-entities and extra-whitespace between the words are cleaned
 */
function api_get_title_html(&$string, $output_encoding = null, $input_encoding = null)
{
    if (@preg_match('/<head.+<title[^>]*>(.*)<\/title>/msi', $string, $matches)) {
        if (empty($output_encoding)) {
            $output_encoding = api_get_system_encoding();
        }
        if (empty($input_encoding)) {
            $input_encoding = api_detect_encoding_html($string);
        }

        return trim(
            @preg_replace(
                '/\s+/',
                ' ',
                api_html_entity_decode(
                    api_convert_encoding($matches[1], $output_encoding, $input_encoding),
                    ENT_QUOTES,
                    $output_encoding
                )
            )
        );
    }

    return '';
}

/**
 * Detects encoding of xml-formatted text.
 *
 * @param string $string           the input xml-formatted text
 * @param string $default_encoding This is the default encoding to be returned
 *                                 if there is no way the xml-text's encoding to be detected.
 *                                 If it not spesified, the system encoding is assumed then.
 *
 * @return string returns the detected encoding
 *
 * @todo The second parameter is to be eliminated. See api_detect_encoding_html().
 */
function api_detect_encoding_xml($string, $default_encoding = null)
{
    if (preg_match(_PCRE_XML_ENCODING, $string, $matches)) {
        return api_refine_encoding_id($matches[1]);
    }
    if (api_is_valid_utf8($string)) {
        return 'UTF-8';
    }
    if (empty($default_encoding)) {
        $default_encoding = _api_mb_internal_encoding();
    }

    return api_refine_encoding_id($default_encoding);
}

/**
 * Converts character encoding of a xml-formatted text.
 * If inside the text the encoding is declared, it is modified accordingly.
 *
 * @param string $string        the text being converted
 * @param string $to_encoding   the encoding that text is being converted to
 * @param string $from_encoding (optional)  The encoding that text is being converted from.
 *                              If it is omited, it is tried to be detected then.
 *
 * @return string returns the converted xml-text
 */
function api_convert_encoding_xml($string, $to_encoding, $from_encoding = null)
{
    return _api_convert_encoding_xml($string, $to_encoding, $from_encoding);
}

/**
 * Converts character encoding of a xml-formatted text into UTF-8.
 * If inside the text the encoding is declared, it is set to UTF-8.
 *
 * @param string $string        the text being converted
 * @param string $from_encoding (optional)  The encoding that text is being converted from.
 *                              If it is omited, it is tried to be detected then.
 *
 * @return string returns the converted xml-text
 */
function api_utf8_encode_xml($string, $from_encoding = null)
{
    return _api_convert_encoding_xml($string, 'UTF-8', $from_encoding);
}

/**
 * Converts character encoding of a xml-formatted text from UTF-8 into a specified encoding.
 * If inside the text the encoding is declared, it is modified accordingly.
 *
 * @param string $string      the text being converted
 * @param string $to_encoding (optional)    The encoding that text is being converted to.
 *                            If it is omitted, the platform character set is assumed.
 *
 * @return string returns the converted xml-text
 */
function api_utf8_decode_xml($string, $to_encoding = 'UTF-8')
{
    return _api_convert_encoding_xml($string, $to_encoding, 'UTF-8');
}

/**
 * Converts character encoding of a xml-formatted text.
 * If inside the text the encoding is declared, it is modified accordingly.
 *
 * @param string $string        the text being converted
 * @param string $to_encoding   the encoding that text is being converted to
 * @param string $from_encoding (optional)  The encoding that text is being converted from.
 *                              If the value is empty, it is tried to be detected then.
 *
 * @return string returns the converted xml-text
 */
function _api_convert_encoding_xml(&$string, $to_encoding, $from_encoding)
{
    if (empty($from_encoding)) {
        $from_encoding = api_detect_encoding_xml($string);
    }
    $to_encoding = api_refine_encoding_id($to_encoding);
    if (!preg_match('/<\?xml.*\?>/m', $string, $matches)) {
        return api_convert_encoding(
            '<?xml version="1.0" encoding="'.$to_encoding.'"?>'."\n".$string,
            $to_encoding,
            $from_encoding
        );
    }
    if (!preg_match(_PCRE_XML_ENCODING, $string)) {
        if (strpos($matches[0], 'standalone') !== false) {
            // The encoding option should precede the standalone option,
            // othewise DOMDocument fails to load the document.
            $replace = str_replace('standalone', ' encoding="'.$to_encoding.'" standalone', $matches[0]);
        } else {
            $replace = str_replace('?>', ' encoding="'.$to_encoding.'"?>', $matches[0]);
        }

        return api_convert_encoding(str_replace($matches[0], $replace, $string), $to_encoding, $from_encoding);
    }
    global $_api_encoding;
    $_api_encoding = api_refine_encoding_id($to_encoding);

    return api_convert_encoding(
        preg_replace_callback(
            _PCRE_XML_ENCODING,
            '_api_convert_encoding_xml_callback',
            $string
        ),
        $to_encoding,
        $from_encoding
    );
}

/**
 * A callback for serving the function _api_convert_encoding_xml().
 *
 * @param array $matches input array of matches corresponding to the xml-declaration
 *
 * @return string returns the xml-declaration with modified encoding
 */
function _api_convert_encoding_xml_callback($matches)
{
    global $_api_encoding;

    return str_replace($matches[1], $_api_encoding, $matches[0]);
}

/* Functions for supporting ASCIIMathML mathematical formulas and ASCIIsvg maathematical graphics */

/**
 * Dectects ASCIIMathML formula presence within a given html text.
 *
 * @param string $html the input html text
 *
 * @return bool returns TRUE when there is a formula found or FALSE otherwise
 */
function api_contains_asciimathml($html)
{
    if (!preg_match_all('/<span[^>]*class\s*=\s*[\'"](.*?)[\'"][^>]*>/mi', $html, $matches)) {
        return false;
    }
    foreach ($matches[1] as $string) {
        $string = ' '.str_replace(',', ' ', $string).' ';
        if (preg_match('/\sAM\s/m', $string)) {
            return true;
        }
    }

    return false;
}

/**
 * Dectects ASCIIsvg graphics presence within a given html text.
 *
 * @param string $html the input html text
 *
 * @return bool returns TRUE when there is a graph found or FALSE otherwise
 */
function api_contains_asciisvg($html)
{
    if (!preg_match_all('/<embed([^>]*?)>/mi', $html, $matches)) {
        return false;
    }
    foreach ($matches[1] as $string) {
        $string = ' '.str_replace(',', ' ', $string).' ';
        if (preg_match('/sscr\s*=\s*[\'"](.*?)[\'"]/m', $string)) {
            return true;
        }
    }

    return false;
}

/**
 * Convers a string from camel case into underscore.
 * Works correctly with ASCII strings only, implementation for human-language strings is not necessary.
 *
 * @param string $string The input string (ASCII)
 *
 * @return string The converted result string
 */
function api_camel_case_to_underscore($string)
{
    return strtolower(preg_replace('/([a-z])([A-Z])/', "$1_$2", $string));
}

/**
 * Converts a string with underscores into camel case.
 * Works correctly with ASCII strings only, implementation for human-language strings is not necessary.
 *
 * @param string $string                The input string (ASCII)
 * @param bool   $capitalise_first_char (optional)
 *                                      If true (default), the function capitalises the first char in the result string
 *
 * @return string The converted result string
 */
function api_underscore_to_camel_case($string, $capitalise_first_char = true)
{
    if ($capitalise_first_char) {
        $string = ucfirst($string);
    }

    return preg_replace_callback('/_([a-z])/', '_api_camelize', $string);
}

// A function for internal use, only for this library.
function _api_camelize($match)
{
    return strtoupper($match[1]);
}

/**
 * Truncates a string.
 *
 * @author Brouckaert Olivier
 *
 * @param string $text     the text to truncate
 * @param int    $length   The approximate desired length. The length of the suffix below is to be added to
 *                         have the total length of the result string.
 * @param string $suffix   a suffix to be added as a replacement
 * @param string $encoding (optional)   The encoding to be used. If it is omitted,
 *                         the platform character set will be used by default.
 * @param bool   $middle   if this parameter is true, truncation is done in the middle of the string
 *
 * @return string truncated string, decorated with the given suffix (replacement)
 */
function api_trunc_str($text, $length = 30, $suffix = '...', $middle = false, $encoding = null)
{
    if (empty($encoding)) {
        $encoding = api_get_system_encoding();
    }
    $text_length = api_strlen($text, $encoding);
    if ($text_length <= $length) {
        return $text;
    }
    if ($middle) {
        return rtrim(
            api_substr(
                $text,
                0,
                round($length / 2),
                $encoding
            )
        ).
        $suffix.
        ltrim(
            api_substr(
                $text,
                -round($length / 2),
                $text_length,
                $encoding
            )
        );
    }

    return rtrim(api_substr($text, 0, $length, $encoding)).$suffix;
}

/**
 * Handling simple and double apostrofe in order that strings be stored properly in database.
 *
 * @author Denes Nagy
 *
 * @param  string variable - the variable to be revised
 *
 * @return string
 */
function domesticate($input)
{
    $input = str_replace(["'", '"'], "''", stripslashes($input));

    return $input;
}

/**
 * function make_clickable($string).
 *
 * @desc   Completes url contained in the text with "<a href ...".
 *         However the function simply returns the submitted text without any
 *         transformation if it already contains some "<a href:" or "<img src=".
 *
 * @param string $text text to be converted
 *
 * @return text after conversion
 *
 * @author Rewritten by Nathan Codding - Feb 6, 2001.
 *         completed by Hugues Peeters - July 22, 2002
 *
 * Actually this function is taken from the PHP BB 1.4 script
 * - Goes through the given string, and replaces xxxx://yyyy with an HTML <a> tag linking
 *     to that URL
 * - Goes through the given string, and replaces www.xxxx.yyyy[zzzz] with an HTML <a> tag linking
 *     to http://www.xxxx.yyyy[/zzzz]
 * - Goes through the given string, and replaces xxxx@yyyy with an HTML mailto: tag linking
 *        to that email address
 * - Only matches these 2 patterns either after a space, or at the beginning of a line
 *
 * Notes: the email one might get annoying - it's easy to make it more restrictive, though.. maybe
 * have it require something like xxxx@yyyy.zzzz or such. We'll see.
 */

/**
 * Callback to convert URI match to HTML A element.
 *
 * This function was backported from 2.5.0 to 2.3.2. Regex callback for {@link * make_clickable()}.
 *
 * @since Wordpress 2.3.2
 *
 * @param array $matches single Regex Match
 *
 * @return string HTML A element with URI address
 */
function _make_url_clickable_cb($matches)
{
    $url = $matches[2];

    if (')' == $matches[3] && strpos($url, '(')) {
        // If the trailing character is a closing parethesis, and the URL has an opening
        // parenthesis in it, add the closing parenthesis to the URL.
        // Then we can let the parenthesis balancer do its thing below.
        $url .= $matches[3];
        $suffix = '';
    } else {
        $suffix = $matches[3];
    }

    // Include parentheses in the URL only if paired
    while (substr_count($url, '(') < substr_count($url, ')')) {
        $suffix = strrchr($url, ')').$suffix;
        $url = substr($url, 0, strrpos($url, ')'));
    }

    $url = esc_url($url);
    if (empty($url)) {
        return $matches[0];
    }

    return $matches[1]."<a href=\"$url\" rel=\"nofollow\">$url</a>".$suffix;
}

/**
 * Checks and cleans a URL.
 *
 * A number of characters are removed from the URL. If the URL is for displaying
 * (the default behaviour) ampersands are also replaced. The 'clean_url' filter
 * is applied to the returned cleaned URL.
 *
 * @since wordpress 2.8.0
 *
 * @uses \wp_kses_bad_protocol() To only permit protocols in the URL set
 *        via $protocols or the common ones set in the function.
 *
 * @param string $url       the URL to be cleaned
 * @param array  $protocols Optional. An array of acceptable protocols.
 *                          Defaults to 'http', 'https', 'ftp', 'ftps', 'mailto', 'news', 'irc', 'gopher',
 *                          'nntp', 'feed', 'telnet', 'mms', 'rtsp', 'svn' if not set.
 * @param string $_context  Private. Use esc_url_raw() for database usage.
 *
 * @return string the cleaned $url after the 'clean_url' filter is applied
 */
function esc_url($url, $protocols = null, $_context = 'display')
{
    //$original_url = $url;
    if ('' == $url) {
        return $url;
    }
    $url = preg_replace('|[^a-z0-9-~+_.?#=!&;,/:%@$\|*\'()\\x80-\\xff]|i', '', $url);
    $strip = ['%0d', '%0a', '%0D', '%0A'];
    $url = _deep_replace($strip, $url);
    $url = str_replace(';//', '://', $url);
    /* If the URL doesn't appear to contain a scheme, we
     * presume it needs http:// appended (unless a relative
     * link starting with /, # or ? or a php file).
     */
    if (strpos($url, ':') === false && !in_array($url[0], ['/', '#', '?']) &&
        !preg_match('/^[a-z0-9-]+?\.php/i', $url)) {
        $url = 'http://'.$url;
    }

    return Security::remove_XSS($url);
}

/**
 * Perform a deep string replace operation to ensure the values in $search are no longer present.
 *
 * Repeats the replacement operation until it no longer replaces anything so as to remove "nested" values
 * e.g. $subject = '%0%0%0DDD', $search ='%0D', $result ='' rather than the '%0%0DD' that
 * str_replace would return
 *
 * @since wordpress  2.8.1
 *
 * @param string|array $search  The value being searched for, otherwise known as the needle.
 *                              An array may be used to designate multiple needles.
 * @param string       $subject the string being searched and replaced on, otherwise known as the haystack
 *
 * @return string the string with the replaced svalues
 */
function _deep_replace($search, $subject)
{
    $subject = (string) $subject;

    $count = 1;
    while ($count) {
        $subject = str_replace($search, '', $subject, $count);
    }

    return $subject;
}

/**
 * Callback to convert URL match to HTML A element.
 *
 * This function was backported from 2.5.0 to 2.3.2. Regex callback for {@link * make_clickable()}.
 *
 * @since wordpress  2.3.2
 *
 * @param array $matches single Regex Match
 *
 * @return string HTML A element with URL address
 */
function _make_web_ftp_clickable_cb($matches)
{
    $ret = '';
    $dest = $matches[2];
    $dest = 'http://'.$dest;
    $dest = esc_url($dest);
    if (empty($dest)) {
        return $matches[0];
    }

    // removed trailing [.,;:)] from URL
    if (in_array(substr($dest, -1), ['.', ',', ';', ':', ')']) === true) {
        $ret = substr($dest, -1);
        $dest = substr($dest, 0, strlen($dest) - 1);
    }

    return $matches[1]."<a href=\"$dest\" rel=\"nofollow\">$dest</a>$ret";
}

/**
 * Callback to convert email address match to HTML A element.
 *
 * This function was backported from 2.5.0 to 2.3.2. Regex callback for {@link * make_clickable()}.
 *
 * @since wordpress  2.3.2
 *
 * @param array $matches single Regex Match
 *
 * @return string HTML A element with email address
 */
function _make_email_clickable_cb($matches)
{
    $email = $matches[2].'@'.$matches[3];

    return $matches[1]."<a href=\"mailto:$email\">$email</a>";
}

/**
 * Convert plaintext URI to HTML links.
 *
 * Converts URI, www and ftp, and email addresses. Finishes by fixing links
 * within links.
 *
 * @since wordpress  0.71
 *
 * @param string $text content to convert URIs
 *
 * @return string content with converted URIs
 */
function make_clickable($text)
{
    $r = '';
    // split out HTML tags
    $textarr = preg_split('/(<[^<>]+>)/', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
    $nested_code_pre = 0; // Keep track of how many levels link is nested inside <pre> or <code>
    foreach ($textarr as $piece) {
        if (preg_match('|^<code[\s>]|i', $piece) || preg_match('|^<pre[\s>]|i', $piece)) {
            $nested_code_pre++;
        } elseif (('</code>' === strtolower($piece) || '</pre>' === strtolower($piece)) && $nested_code_pre) {
            $nested_code_pre--;
        }

        if ($nested_code_pre ||
            empty($piece) ||
            ($piece[0] === '<' && !preg_match('|^<\s*[\w]{1,20}+://|', $piece))
        ) {
            $r .= $piece;
            continue;
        }

        // Long strings might contain expensive edge cases ...
        if (10000 < strlen($piece)) {
            // ... break it up
            foreach (_split_str_by_whitespace($piece, 2100) as $chunk) {
                // 2100: Extra room for scheme and leading and trailing paretheses
                if (2101 < strlen($chunk)) {
                    $r .= $chunk; // Too big, no whitespace: bail.
                } else {
                    $r .= make_clickable($chunk);
                }
            }
        } else {
            $ret = " $piece "; // Pad with whitespace to simplify the regexes

            $url_clickable = '~
				([\\s(<.,;:!?])                                        # 1: Leading whitespace, or punctuation
				(                                                      # 2: URL
					[\\w]{1,20}+://                                # Scheme and hier-part prefix
					(?=\S{1,2000}\s)                               # Limit to URLs less than about 2000 characters long
					[\\w\\x80-\\xff#%\\~/@\\[\\]*(+=&$-]*+         # Non-punctuation URL character
					(?:                                            # Unroll the Loop: Only allow puctuation URL character if followed by a non-punctuation URL character
						[\'.,;:!?)]                            # Punctuation URL character
						[\\w\\x80-\\xff#%\\~/@\\[\\]*(+=&$-]++ # Non-punctuation URL character
					)*
				)
				(\)?)                                                  # 3: Trailing closing parenthesis (for parethesis balancing post processing)
			~xS'; // The regex is a non-anchored pattern and does not have a single fixed starting character.
            // Tell PCRE to spend more time optimizing since, when used on a page load, it will probably be used several times.

            $ret = preg_replace_callback($url_clickable, '_make_url_clickable_cb', $ret);
            $ret = preg_replace_callback(
                '#([\s>])((www|ftp)\.[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]+)#is',
                '_make_web_ftp_clickable_cb',
                $ret
            );
            $ret = preg_replace_callback(
                '#([\s>])([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})#i',
                '_make_email_clickable_cb',
                $ret
            );

            $ret = substr($ret, 1, -1); // Remove our whitespace padding.
            $r .= $ret;
        }
    }

    // Cleanup of accidental links within links
    $r = preg_replace('#(<a([ \r\n\t]+[^>]+?>|>))<a [^>]+?>([^>]+?)</a></a>#i', "$1$3</a>", $r);

    return $r;
}

/**
 * Breaks a string into chunks by splitting at whitespace characters.
 * The length of each returned chunk is as close to the specified length goal as possible,
 * with the caveat that each chunk includes its trailing delimiter.
 * Chunks longer than the goal are guaranteed to not have any inner whitespace.
 *
 * Joining the returned chunks with empty delimiters reconstructs the input string losslessly.
 *
 * Input string must have no null characters (or eventual transformations on output chunks
 * must not care about null characters)
 *
 * <code>
 * _split_str_by_whitespace( "1234 67890 1234 67890a cd 1234   890 123456789 1234567890a    45678   1 3 5 7 90 ", 10 ) ==
 * array (
 *   0 => '1234 67890 ',  // 11 characters: Perfect split
 *   1 => '1234 ',        //  5 characters: '1234 67890a' was too long
 *   2 => '67890a cd ',   // 10 characters: '67890a cd 1234' was too long
 *   3 => '1234   890 ',  // 11 characters: Perfect split
 *   4 => '123456789 ',   // 10 characters: '123456789 1234567890a' was too long
 *   5 => '1234567890a ', // 12 characters: Too long, but no inner whitespace on which to split
 *   6 => '   45678   ',  // 11 characters: Perfect split
 *   7 => '1 3 5 7 9',    //  9 characters: End of $string
 * );
 * </code>
 *
 * @since wordpress  3.4.0
 *
 * @param string $string the string to split
 * @param int    $goal   the desired chunk length
 *
 * @return array numeric array of chunks
 */
function _split_str_by_whitespace($string, $goal)
{
    $chunks = [];
    $string_nullspace = strtr($string, "\r\n\t\v\f ", "\000\000\000\000\000\000");
    while ($goal < strlen($string_nullspace)) {
        $pos = strrpos(substr($string_nullspace, 0, $goal + 1), "\000");

        if (false === $pos) {
            $pos = strpos($string_nullspace, "\000", $goal + 1);
            if (false === $pos) {
                break;
            }
        }

        $chunks[] = substr($string, 0, $pos + 1);
        $string = substr($string, $pos + 1);
        $string_nullspace = substr($string_nullspace, $pos + 1);
    }

    if ($string) {
        $chunks[] = $string;
    }

    return $chunks;
}

/**
 * This functions cuts a paragraph
 * i.e cut('Merry Xmas from Lima',13) = "Merry Xmas fr...".
 *
 * @param string    The text to "cut"
 * @param int       Count of chars
 * @param bool      Whether to embed in a <span title="...">...</span>
 *
 * @return string
 * */
function cut($text, $maxchar, $embed = false)
{
    if (api_strlen($text) > $maxchar) {
        if ($embed) {
            return '<p title="'.$text.'">'.api_substr($text, 0, $maxchar).'...</p>';
        }

        return api_substr($text, 0, $maxchar).' ...';
    }

    return $text;
}

/**
 * Show a number as only integers if no decimals, but will show 2 decimals if exist.
 *
 * @param mixed     Number to convert
 * @param int       Decimal points 0=never, 1=if needed, 2=always
 * @param string $decimalPoint
 * @param string $thousandsSeparator
 *
 * @return mixed An integer or a float depends on the parameter
 */
function float_format($number, $flag = 1, $decimalPoint = '.', $thousandsSeparator = ',')
{
    if (is_numeric($number)) {
        if (!$number) {
            $result = ($flag == 2 ? '0.'.str_repeat('0', EXERCISE_NUMBER_OF_DECIMALS) : '0');
        } else {
            if (floor($number) == $number) {
                $result = number_format(
                    $number,
                    ($flag == 2 ? EXERCISE_NUMBER_OF_DECIMALS : 0),
                    $decimalPoint,
                    $thousandsSeparator
                );
            } else {
                $result = number_format(
                    round($number, 2),
                    ($flag == 0 ? 0 : EXERCISE_NUMBER_OF_DECIMALS),
                    $decimalPoint,
                    $thousandsSeparator
                );
            }
        }

        return $result;
    }
}

// TODO: To be checked for correct timezone management.
/**
 * Function to obtain last week timestamps.
 *
 * @return array Times for every day inside week
 */
function get_last_week()
{
    $week = date('W');
    $year = date('Y');

    $lastweek = $week - 1;
    if ($lastweek == 0) {
        $week = 52;
        $year--;
    }

    $lastweek = sprintf("%02d", $lastweek);
    $arrdays = [];
    for ($i = 1; $i <= 7; $i++) {
        $arrdays[] = strtotime("$year"."W$lastweek"."$i");
    }

    return $arrdays;
}

/**
 * Gets the week from a day.
 *
 * @param   string   Date in UTC (2010-01-01 12:12:12)
 *
 * @return int Returns an integer with the week number of the year
 */
function get_week_from_day($date)
{
    if (!empty($date)) {
        $time = api_strtotime($date, 'UTC');

        return date('W', $time);
    }

    return date('W');
}

/**
 * This function splits the string into words and then joins them back together again one by one.
 * Example: "Test example of a long string"
 * substrwords(5) = Test ... *.
 *
 * @param string
 * @param int the max number of character
 * @param string how the string will be end
 *
 * @return a reduce string
 */
function substrwords($text, $maxchar, $end = '...')
{
    if (strlen($text) > $maxchar) {
        $words = explode(" ", $text);
        $output = '';
        $i = 0;
        while (1) {
            $length = (strlen($output) + strlen($words[$i]));
            if ($length > $maxchar) {
                break;
            } else {
                $output = $output." ".$words[$i];
                $i++;
            }
        }
    } else {
        $output = $text;

        return $output;
    }

    return $output.$end;
}

function implode_with_key($glue, $array)
{
    if (!empty($array)) {
        $string = '';
        foreach ($array as $key => $value) {
            if (empty($value)) {
                $value = 'null';
            }
            $string .= $key." : ".$value." $glue ";
        }

        return $string;
    }

    return '';
}

/**
 * Transform the file size in a human readable format.
 *
 * @param int $file_size Size of the file in bytes
 *
 * @return string A human readable representation of the file size
 */
function format_file_size($file_size)
{
    $file_size = (int) $file_size;
    if ($file_size >= 1073741824) {
        $file_size = (round($file_size / 1073741824 * 100) / 100).'G';
    } elseif ($file_size >= 1048576) {
        $file_size = (round($file_size / 1048576 * 100) / 100).'M';
    } elseif ($file_size >= 1024) {
        $file_size = (round($file_size / 1024 * 100) / 100).'k';
    } else {
        $file_size = $file_size.'B';
    }

    return $file_size;
}

/**
 * Converts an string CLEANYO[admin][amann,acostea]
 * into an array:.
 *
 * array(
 *  CLEANYO
 *  admin
 *  amann,acostea
 * )
 *
 * @param $array
 *
 * @return array
 */
function bracketsToArray($array)
{
    return preg_split('/[\[\]]+/', $array, -1, PREG_SPLIT_NO_EMPTY);
}

/**
 * @param string $string
 * @param bool   $capitalizeFirstCharacter
 *
 * @return mixed
 */
function underScoreToCamelCase($string, $capitalizeFirstCharacter = true)
{
    $str = str_replace(' ', '', ucwords(str_replace('_', ' ', $string)));

    if (!$capitalizeFirstCharacter) {
        $str[0] = strtolower($str[0]);
    }

    return $str;
}

/**
 * @param string $value
 */
function trim_value(&$value)
{
    $value = trim($value);
}

/**
 * Strips only the given tags in the given HTML string.
 *
 * @param string $html
 * @param array  $tags
 *
 * @return string
 */
function strip_tags_blacklist($html, $tags)
{
    foreach ($tags as $tag) {
        $regex = '#<\s*'.$tag.'[^>]*>.*?<\s*/\s*'.$tag.'>#msi';
        $html = preg_replace($regex, '', $html);
    }

    return $html;
}