/common/libraries/plugin/wiki/mediawiki/normal/UtfNormal.php

<?php

# Copyright (C) 2004 Brion Vibber <brion@pobox.com>
# http://www.mediawiki.org/
#
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
# http://www.gnu.org/copyleft/gpl.html




/**
 * @defgroup UtfNormal UtfNormal
 */



/** */

require_once dirname(__FILE__) . '/UtfNormalUtil.php';



global $utfCombiningClass, $utfCanonicalComp, $utfCanonicalDecomp;

$utfCombiningClass = NULL;

$utfCanonicalComp = NULL;

$utfCanonicalDecomp = NULL;



# Load compatibility decompositions on demand if they are needed.
global $utfCompatibilityDecomp;

$utfCompatibilityDecomp = NULL;



/**
 * For using the ICU wrapper
 */

define('UNORM_NONE', 1);

define('UNORM_NFD', 2);

define('UNORM_NFKD', 3);

define('UNORM_NFC', 4);

define('UNORM_DEFAULT', UNORM_NFC);

define('UNORM_NFKC', 5);

define('UNORM_FCD', 6);



define('NORMALIZE_ICU', function_exists('utf8_normalize'));



/**
 * Unicode normalization routines for working with UTF-8 strings.
 * Currently assumes that input strings are valid UTF-8!
 *
 * Not as fast as I'd like, but should be usable for most purposes.
 * UtfNormal::toNFC() will bail early if given ASCII text or text
 * it can quickly deterimine is already normalized.
 *
 * All functions can be called static.
 *
 * See description of forms at http://www.unicode.org/reports/tr15/
 *
 * @ingroup UtfNormal
 */

class UtfNormal

{



    /**
     * The ultimate convenience function! Clean up invalid UTF-8 sequences,
     * and convert to normal form C, canonical composition.
     *
     * Fast return for pure ASCII strings; some lesser optimizations for
     * strings containing only known-good characters. Not as fast as toNFC().
     *
     * @param $string String: a UTF-8 string
     * @return string a clean, shiny, normalized UTF-8 string
     */

    static function cleanUp($string)

    {

        if (NORMALIZE_ICU)

        {

            # We exclude a few chars that ICU would not.
            $string = preg_replace('/[\x00-\x08\x0b\x0c\x0e-\x1f]/', UTF8_REPLACEMENT, $string);

            $string = str_replace(UTF8_FFFE, UTF8_REPLACEMENT, $string);

            $string = str_replace(UTF8_FFFF, UTF8_REPLACEMENT, $string);

            

            # UnicodeString constructor fails if the string ends with a
            # head byte. Add a junk char at the end, we'll strip it off.
            return rtrim(utf8_normalize($string . "\x01", UNORM_NFC), "\x01");

        }

        elseif (UtfNormal :: quickIsNFCVerify($string))

        {

            # Side effect -- $string has had UTF-8 errors cleaned up.
            return $string;

        }

        else

        {

            return UtfNormal :: NFC($string);

        }

    }



    /**
     * Convert a UTF-8 string to normal form C, canonical composition.
     * Fast return for pure ASCII strings; some lesser optimizations for
     * strings containing only known-good characters.
     *
     * @param $string String: a valid UTF-8 string. Input is not validated.
     * @return string a UTF-8 string in normal form C
     */

    static function toNFC($string)

    {

        if (NORMALIZE_ICU)

            return utf8_normalize($string, UNORM_NFC);

        elseif (UtfNormal :: quickIsNFC($string))

            return $string;

        else

            return UtfNormal :: NFC($string);

    }



    /**
     * Convert a UTF-8 string to normal form D, canonical decomposition.
     * Fast return for pure ASCII strings.
     *
     * @param $string String: a valid UTF-8 string. Input is not validated.
     * @return string a UTF-8 string in normal form D
     */

    static function toNFD($string)

    {

        if (NORMALIZE_ICU)

            return utf8_normalize($string, UNORM_NFD);

        elseif (preg_match('/[\x80-\xff]/', $string))

            return UtfNormal :: NFD($string);

        else

            return $string;

    }



    /**
     * Convert a UTF-8 string to normal form KC, compatibility composition.
     * This may cause irreversible information loss, use judiciously.
     * Fast return for pure ASCII strings.
     *
     * @param $string String: a valid UTF-8 string. Input is not validated.
     * @return string a UTF-8 string in normal form KC
     */

    static function toNFKC($string)

    {

        if (NORMALIZE_ICU)

            return utf8_normalize($string, UNORM_NFKC);

        elseif (preg_match('/[\x80-\xff]/', $string))

            return UtfNormal :: NFKC($string);

        else

            return $string;

    }



    /**
     * Convert a UTF-8 string to normal form KD, compatibility decomposition.
     * This may cause irreversible information loss, use judiciously.
     * Fast return for pure ASCII strings.
     *
     * @param $string String: a valid UTF-8 string. Input is not validated.
     * @return string a UTF-8 string in normal form KD
     */

    static function toNFKD($string)

    {

        if (NORMALIZE_ICU)

            return utf8_normalize($string, UNORM_NFKD);

        elseif (preg_match('/[\x80-\xff]/', $string))

            return UtfNormal :: NFKD($string);

        else

            return $string;

    }



    /**
     * Load the basic composition data if necessary
     * @private
     */

    static function loadData()

    {

        global $utfCombiningClass;

        if (! isset($utfCombiningClass))

        {

            require_once (dirname(__FILE__) . '/UtfNormalData.inc');

        }

    }



    /**
     * Returns true if the string is _definitely_ in NFC.
     * Returns false if not or uncertain.
     * @param $string String: a valid UTF-8 string. Input is not validated.
     * @return bool
     */

    static function quickIsNFC($string)

    {

        # ASCII is always valid NFC!
        # If it's pure ASCII, let it through.
        if (! preg_match('/[\x80-\xff]/', $string))

            return true;

        

        UtfNormal :: loadData();

        global $utfCheckNFC, $utfCombiningClass;

        $len = strlen($string);

        for($i = 0; $i < $len; $i ++)

        {

            $c = $string{$i};

            $n = ord($c);

            if ($n < 0x80)

            {

                continue;

            }

            elseif ($n >= 0xf0)

            {

                $c = substr($string, $i, 4);

                $i += 3;

            }

            elseif ($n >= 0xe0)

            {

                $c = substr($string, $i, 3);

                $i += 2;

            }

            elseif ($n >= 0xc0)

            {

                $c = substr($string, $i, 2);

                $i ++;

            }

            if (isset($utfCheckNFC[$c]))

            {

                # If it's NO or MAYBE, bail and do the slow check.
                return false;

            }

            if (isset($utfCombiningClass[$c]))

            {

                # Combining character? We might have to do sorting, at least.
                return false;

            }

        }

        return true;

    }



    /**
     * Returns true if the string is _definitely_ in NFC.
     * Returns false if not or uncertain.
     * @param $string String: a UTF-8 string, altered on output to be valid UTF-8 safe for XML.
     */

    static function quickIsNFCVerify(&$string)

    {

        # Screen out some characters that eg won't be allowed in XML
        $string = preg_replace('/[\x00-\x08\x0b\x0c\x0e-\x1f]/', UTF8_REPLACEMENT, $string);

        

        # ASCII is always valid NFC!
        # If we're only ever given plain ASCII, we can avoid the overhead
        # of initializing the decomposition tables by skipping out early.
        if (! preg_match('/[\x80-\xff]/', $string))

            return true;

        

        static $checkit = null, $tailBytes = null, $utfCheckOrCombining = null;

        if (! isset($checkit))

        {

            # Load/build some scary lookup tables...
            UtfNormal :: loadData();

            global $utfCheckNFC, $utfCombiningClass;

            

            $utfCheckOrCombining = array_merge($utfCheckNFC, $utfCombiningClass);

            

            # Head bytes for sequences which we should do further validity checks
            $checkit = array_flip(array_map('chr', array(0xc0, 0xc1, 0xe0, 0xed, 0xef, 0xf0, 0xf1, 0xf2, 

                    0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff)));

            

            # Each UTF-8 head byte is followed by a certain
            # number of tail bytes.
            $tailBytes = array();

            for($n = 0; $n < 256; $n ++)

            {

                if ($n < 0xc0)

                {

                    $remaining = 0;

                }

                elseif ($n < 0xe0)

                {

                    $remaining = 1;

                }

                elseif ($n < 0xf0)

                {

                    $remaining = 2;

                }

                elseif ($n < 0xf8)

                {

                    $remaining = 3;

                }

                elseif ($n < 0xfc)

                {

                    $remaining = 4;

                }

                elseif ($n < 0xfe)

                {

                    $remaining = 5;

                }

                else

                {

                    $remaining = 0;

                }

                $tailBytes[chr($n)] = $remaining;

            }

        }

        

        # Chop the text into pure-ASCII and non-ASCII areas;
        # large ASCII parts can be handled much more quickly.
        # Don't chop up Unicode areas for punctuation, though,
        # that wastes energy.
        $matches = array();

        preg_match_all('/([\x00-\x7f]+|[\x80-\xff][\x00-\x40\x5b-\x5f\x7b-\xff]*)/', $string, $matches);

        

        $looksNormal = true;

        $base = 0;

        $replace = array();

        foreach ($matches[1] as $str)

        {

            $chunk = strlen($str);

            

            if ($str{0} < "\x80")

            {

                # ASCII chunk: guaranteed to be valid UTF-8
                # and in normal form C, so skip over it.
                $base += $chunk;

                continue;

            }

            

            # We'll have to examine the chunk byte by byte to ensure
            # that it consists of valid UTF-8 sequences, and to see
            # if any of them might not be normalized.
            #
            # Since PHP is not the fastest language on earth, some of
            # this code is a little ugly with inner loop optimizations.
            



            $head = '';

            $len = $chunk + 1; # Counting down is faster. I'm *so* sorry.
            



            for($i = - 1; -- $len;)

            {

                if ($remaining = $tailBytes[$c = $str{++ $i}])

                {

                    # UTF-8 head byte!
                    $sequence = $head = $c;

                    do

                    {

                        # Look for the defined number of tail bytes...
                        if (-- $len && ($c = $str{++ $i}) >= "\x80" && $c < "\xc0")

                        {

                            # Legal tail bytes are nice.
                            $sequence .= $c;

                        }

                        else

                        {

                            if (0 == $len)

                            {

                                # Premature end of string!
                                # Drop a replacement character into output to
                                # represent the invalid UTF-8 sequence.
                                $replace[] = array(

                                        UTF8_REPLACEMENT, $base + $i + 1 - strlen($sequence), strlen($sequence));

                                break 2;

                            }

                            else

                            {

                                # Illegal tail byte; abandon the sequence.
                                $replace[] = array(UTF8_REPLACEMENT, 

                                        $base + $i - strlen($sequence), strlen($sequence));

                                # Back up and reprocess this byte; it may itself
                                # be a legal ASCII or UTF-8 sequence head.
                                -- $i;

                                ++ $len;

                                continue 2;

                            }

                        }

                    }

                    while (-- $remaining);

                    

                    if (isset($checkit[$head]))

                    {

                        # Do some more detailed validity checks, for
                        # invalid characters and illegal sequences.
                        if ($head == "\xed")

                        {

                            # 0xed is relatively frequent in Korean, which
                            # abuts the surrogate area, so we're doing
                            # this check separately to speed things up.
                            



                            if ($sequence >= UTF8_SURROGATE_FIRST)

                            {

                                # Surrogates are legal only in UTF-16 code.
                                # They are totally forbidden here in UTF-8
                                # utopia.
                                $replace[] = array(

                                        UTF8_REPLACEMENT, $base + $i + 1 - strlen($sequence), strlen($sequence));

                                $head = '';

                                continue;

                            }

                        }

                        else

                        {

                            # Slower, but rarer checks...
                            $n = ord($head);

                            if (# "Overlong sequences" are those that are syntactically
# correct but use more UTF-8 bytes than are necessary to
                            # encode a character. NaĂŻve string comparisons can be
                            # tricked into failing to see a match for an ASCII
                            # character, for instance, which can be a security hole
                            # if blacklist checks are being used.
                            ($n < 0xc2 && $sequence <= UTF8_OVERLONG_A) || ($n == 0xe0 && $sequence <= UTF8_OVERLONG_B) || ($n == 0xf0 && $sequence <= UTF8_OVERLONG_C) || 



                            # U+FFFE and U+FFFF are explicitly forbidden in Unicode.
                            ($n == 0xef && ($sequence == UTF8_FFFE) || ($sequence == UTF8_FFFF)) || 



                            # Unicode has been limited to 21 bits; longer
                            # sequences are not allowed.
                            ($n >= 0xf0 && $sequence > UTF8_MAX))

                            {

                                

                                $replace[] = array(UTF8_REPLACEMENT, $base + $i + 1 - strlen($sequence), 

                                        strlen($sequence));

                                $head = '';

                                continue;

                            }

                        }

                    }

                    

                    if (isset($utfCheckOrCombining[$sequence]))

                    {

                        # If it's NO or MAYBE, we'll have to rip
                        # the string apart and put it back together.
                        # That's going to be mighty slow.
                        $looksNormal = false;

                    }

                    

                    # The sequence is legal!
                    $head = '';

                }

                elseif ($c < "\x80")

                {

                    # ASCII byte.
                    $head = '';

                }

                elseif ($c < "\xc0")

                {

                    # Illegal tail bytes
                    if ($head == '')

                    {

                        # Out of the blue!
                        $replace[] = array(UTF8_REPLACEMENT, $base + $i, 1);

                    }

                    else

                    {

                        # Don't add if we're continuing a broken sequence;
                        # we already put a replacement character when we looked
                        # at the broken sequence.
                        $replace[] = array('', 

                                $base + $i, 1);

                    }

                }

                else

                {

                    # Miscellaneous freaks.
                    $replace[] = array(UTF8_REPLACEMENT, $base + $i, 1);

                    $head = '';

                }

            }

            $base += $chunk;

        }

        if (count($replace))

        {

            # There were illegal UTF-8 sequences we need to fix up.
            $out = '';

            $last = 0;

            foreach ($replace as $rep)

            {

                list($replacement, $start, $length) = $rep;

                if ($last < $start)

                {

                    $out .= substr($string, $last, $start - $last);

                }

                $out .= $replacement;

                $last = $start + $length;

            }

            if ($last < strlen($string))

            {

                $out .= substr($string, $last);

            }

            $string = $out;

        }

        return $looksNormal;

    }



    # These take a string and run the normalization on them, without
    # checking for validity or any optimization etc. Input must be
    # VALID UTF-8!
    /**
     * @param $string string
     * @return string
     * @private
     */

    static function NFC($string)

    {

        return UtfNormal :: fastCompose(UtfNormal :: NFD($string));

    }



    /**
     * @param $string string
     * @return string
     * @private
     */

    static function NFD($string)

    {

        UtfNormal :: loadData();

        global $utfCanonicalDecomp;

        return UtfNormal :: fastCombiningSort(UtfNormal :: fastDecompose($string, $utfCanonicalDecomp));

    }



    /**
     * @param $string string
     * @return string
     * @private
     */

    static function NFKC($string)

    {

        return UtfNormal :: fastCompose(UtfNormal :: NFKD($string));

    }



    /**
     * @param $string string
     * @return string
     * @private
     */

    static function NFKD($string)

    {

        global $utfCompatibilityDecomp;

        if (! isset($utfCompatibilityDecomp))

        {

            require_once ('UtfNormalDataK.inc');

        }

        return UtfNormal :: fastCombiningSort(UtfNormal :: fastDecompose($string, $utfCompatibilityDecomp));

    }



    /**
     * Perform decomposition of a UTF-8 string into either D or KD form
     * (depending on which decomposition map is passed to us).
     * Input is assumed to be *valid* UTF-8. Invalid code will break.
     * @private
     * @param $string String: valid UTF-8 string
     * @param $map Array: hash of expanded decomposition map
     * @return string a UTF-8 string decomposed, not yet normalized (needs sorting)
     */

    static function fastDecompose($string, $map)

    {

        UtfNormal :: loadData();

        $len = strlen($string);

        $out = '';

        for($i = 0; $i < $len; $i ++)

        {

            $c = $string{$i};

            $n = ord($c);

            if ($n < 0x80)

            {

                # ASCII chars never decompose
                # THEY ARE IMMORTAL
                $out .= $c;

                continue;

            }

            elseif ($n >= 0xf0)

            {

                $c = substr($string, $i, 4);

                $i += 3;

            }

            elseif ($n >= 0xe0)

            {

                $c = substr($string, $i, 3);

                $i += 2;

            }

            elseif ($n >= 0xc0)

            {

                $c = substr($string, $i, 2);

                $i ++;

            }

            if (isset($map[$c]))

            {

                $out .= $map[$c];

                continue;

            }

            else

            {

                if ($c >= UTF8_HANGUL_FIRST && $c <= UTF8_HANGUL_LAST)

                {

                    # Decompose a hangul syllable into jamo;
                    # hardcoded for three-byte UTF-8 sequence.
                    # A lookup table would be slightly faster,
                    # but adds a lot of memory & disk needs.
                    #
                    $index = ((ord($c{0}) & 0x0f) << 12 | (ord($c{1}) & 0x3f) << 6 | (ord($c{2}) & 0x3f)) - UNICODE_HANGUL_FIRST;

                    $l = intval($index / UNICODE_HANGUL_NCOUNT);

                    $v = intval(($index % UNICODE_HANGUL_NCOUNT) / UNICODE_HANGUL_TCOUNT);

                    $t = $index % UNICODE_HANGUL_TCOUNT;

                    $out .= "\xe1\x84" . chr(0x80 + $l) . "\xe1\x85" . chr(0xa1 + $v);

                    if ($t >= 25)

                    {

                        $out .= "\xe1\x87" . chr(0x80 + $t - 25);

                    }

                    elseif ($t)

                    {

                        $out .= "\xe1\x86" . chr(0xa7 + $t);

                    }

                    continue;

                }

            }

            $out .= $c;

        }

        return $out;

    }



    /**
     * Sorts combining characters into canonical order. This is the
     * final step in creating decomposed normal forms D and KD.
     * @private
     * @param $string String: a valid, decomposed UTF-8 string. Input is not validated.
     * @return string a UTF-8 string with combining characters sorted in canonical order
     */

    static function fastCombiningSort($string)

    {

        UtfNormal :: loadData();

        global $utfCombiningClass;

        $len = strlen($string);

        $out = '';

        $combiners = array();

        $lastClass = - 1;

        for($i = 0; $i < $len; $i ++)

        {

            $c = $string{$i};

            $n = ord($c);

            if ($n >= 0x80)

            {

                if ($n >= 0xf0)

                {

                    $c = substr($string, $i, 4);

                    $i += 3;

                }

                elseif ($n >= 0xe0)

                {

                    $c = substr($string, $i, 3);

                    $i += 2;

                }

                elseif ($n >= 0xc0)

                {

                    $c = substr($string, $i, 2);

                    $i ++;

                }

                if (isset($utfCombiningClass[$c]))

                {

                    $lastClass = $utfCombiningClass[$c];

                    if (isset($combiners[$lastClass]))

                    {

                        $combiners[$lastClass] .= $c;

                    }

                    else

                    {

                        $combiners[$lastClass] = $c;

                    }

                    continue;

                }

            }

            if ($lastClass)

            {

                ksort($combiners);

                $out .= implode('', $combiners);

                $combiners = array();

            }

            $out .= $c;

            $lastClass = 0;

        }

        if ($lastClass)

        {

            ksort($combiners);

            $out .= implode('', $combiners);

        }

        return $out;

    }



    /**
     * Produces canonically composed sequences, i.e. normal form C or KC.
     *
     * @private
     * @param $string String: a valid UTF-8 string in sorted normal form D or KD. Input is not validated.
     * @return string a UTF-8 string with canonical precomposed characters used where possible
     */

    static function fastCompose($string)

    {

        UtfNormal :: loadData();

        global $utfCanonicalComp, $utfCombiningClass;

        $len = strlen($string);

        $out = '';

        $lastClass = - 1;

        $lastHangul = 0;

        $startChar = '';

        $combining = '';

        $x1 = ord(substr(UTF8_HANGUL_VBASE, 0, 1));

        $x2 = ord(substr(UTF8_HANGUL_TEND, 0, 1));

        for($i = 0; $i < $len; $i ++)

        {

            $c = $string{$i};

            $n = ord($c);

            if ($n < 0x80)

            {

                # No combining characters here...
                $out .= $startChar;

                $out .= $combining;

                $startChar = $c;

                $combining = '';

                $lastClass = 0;

                continue;

            }

            elseif ($n >= 0xf0)

            {

                $c = substr($string, $i, 4);

                $i += 3;

            }

            elseif ($n >= 0xe0)

            {

                $c = substr($string, $i, 3);

                $i += 2;

            }

            elseif ($n >= 0xc0)

            {

                $c = substr($string, $i, 2);

                $i ++;

            }

            $pair = $startChar . $c;

            if ($n > 0x80)

            {

                if (isset($utfCombiningClass[$c]))

                {

                    # A combining char; see what we can do with it
                    $class = $utfCombiningClass[$c];

                    if (! empty($startChar) && $lastClass < $class && $class > 0 && isset($utfCanonicalComp[$pair]))

                    {

                        $startChar = $utfCanonicalComp[$pair];

                        $class = 0;

                    }

                    else

                    {

                        $combining .= $c;

                    }

                    $lastClass = $class;

                    $lastHangul = 0;

                    continue;

                }

            }

            # New start char
            if ($lastClass == 0)

            {

                if (isset($utfCanonicalComp[$pair]))

                {

                    $startChar = $utfCanonicalComp[$pair];

                    $lastHangul = 0;

                    continue;

                }

                if ($n >= $x1 && $n <= $x2)

                {

                    # WARNING: Hangul code is painfully slow.
                    # I apologize for this ugly, ugly code; however
                    # performance is even more teh suck if we call
                    # out to nice clean functions. Lookup tables are
                    # marginally faster, but require a lot of space.
                    #
                    if ($c >= UTF8_HANGUL_VBASE && $c <= UTF8_HANGUL_VEND && $startChar >= UTF8_HANGUL_LBASE && $startChar <= UTF8_HANGUL_LEND)

                    {

                        #
                        #$lIndex = utf8ToCodepoint( $startChar ) - UNICODE_HANGUL_LBASE;
                        #$vIndex = utf8ToCodepoint( $c ) - UNICODE_HANGUL_VBASE;
                        $lIndex = ord($startChar{2}) - 0x80;

                        $vIndex = ord($c{2}) - 0xa1;

                        

                        $hangulPoint = UNICODE_HANGUL_FIRST + UNICODE_HANGUL_TCOUNT * (UNICODE_HANGUL_VCOUNT * $lIndex + $vIndex);

                        

                        # Hardcode the limited-range UTF-8 conversion:
                        $startChar = chr($hangulPoint >> 12 & 0x0f | 0xe0) . chr($hangulPoint >> 6 & 0x3f | 0x80) . chr($hangulPoint & 0x3f | 0x80);

                        $lastHangul = 0;

                        continue;

                    }

                    elseif ($c >= UTF8_HANGUL_TBASE && $c <= UTF8_HANGUL_TEND && $startChar >= UTF8_HANGUL_FIRST && $startChar <= UTF8_HANGUL_LAST && ! $lastHangul)

                    {

                        # $tIndex = utf8ToCodepoint( $c ) - UNICODE_HANGUL_TBASE;
                        $tIndex = ord($c{2}) - 0xa7;

                        if ($tIndex < 0)

                            $tIndex = ord($c{2}) - 0x80 + (0x11c0 - 0x11a7);

                        

     # Increment the code point by $tIndex, without
                        # the function overhead of decoding and recoding UTF-8
                        #
                        $tail = ord($startChar{2}) + $tIndex;

                        if ($tail > 0xbf)

                        {

                            $tail -= 0x40;

                            $mid = ord($startChar{1}) + 1;

                            if ($mid > 0xbf)

                            {

                                $startChar{0} = chr(ord($startChar{0}) + 1);

                                $mid -= 0x40;

                            }

                            $startChar{1} = chr($mid);

                        }

                        $startChar{2} = chr($tail);

                        

                        # If there's another jamo char after this, *don't* try to merge it.
                        $lastHangul = 1;

                        continue;

                    }

                }

            }

            $out .= $startChar;

            $out .= $combining;

            $startChar = $c;

            $combining = '';

            $lastClass = 0;

            $lastHangul = 0;

        }

        $out .= $startChar . $combining;

        return $out;

    }



    /**
     * This is just used for the benchmark, comparing how long it takes to
     * interate through a string without really doing anything of substance.
     * @param $string string
     * @return string
     */

    static function placebo($string)

    {

        $len = strlen($string);

        $out = '';

        for($i = 0; $i < $len; $i ++)

        {

            $out .= $string{$i};

        }

        return $out;

    }

}