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[autoinstallsdev/mediawiki.git] / includes / normal / UtfNormal.php
diff --git a/includes/normal/UtfNormal.php b/includes/normal/UtfNormal.php
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-<?php
-/**
- * Unicode normalization routines
- *
- * Copyright © 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
- *
- * @file
- * @ingroup UtfNormal
- */
-
-/**
- * @defgroup UtfNormal UtfNormal
- */
-
-require_once dirname(__FILE__).'/UtfNormalUtil.php';
-
-/**
- * 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' ) );
-define( 'NORMALIZE_INTL', function_exists( 'normalizer_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 {
-       static $utfCombiningClass = null;
-       static $utfCanonicalComp = null;
-       static $utfCanonicalDecomp = null;
-
-       # Load compatibility decompositions on demand if they are needed.
-       static $utfCompatibilityDecomp = null;
-
-       static $utfCheckNFC;
-
-       /**
-        * 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 ) {
-                       $string = self::replaceForNativeNormalize( $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( NORMALIZE_INTL ) {
-                       $string = self::replaceForNativeNormalize( $string );
-                       $norm = normalizer_normalize( $string, Normalizer::FORM_C );
-                       if( $norm === null || $norm === false ) {
-                               # normalizer_normalize will either return false or null
-                               # (depending on which doc you read) if invalid utf8 string.
-                               # quickIsNFCVerify cleans up invalid sequences.
-
-                               if( UtfNormal::quickIsNFCVerify( $string ) ) {
-                                       # if that's true, the string is actually already normal.
-                                       return $string;
-                               } else {
-                                       # Now we are valid but non-normal
-                                       return normalizer_normalize( $string, Normalizer::FORM_C );
-                               }
-                       } else {
-                               return $norm;
-                       }
-               } 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_INTL )
-                       return normalizer_normalize( $string, Normalizer::FORM_C );
-               elseif( 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_INTL )
-                       return normalizer_normalize( $string, Normalizer::FORM_D );
-               elseif( 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_INTL )
-                       return normalizer_normalize( $string, Normalizer::FORM_KC );
-               elseif( 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_INTL )
-                       return normalizer_normalize( $string, Normalizer::FORM_KD );
-               elseif( NORMALIZE_ICU )
-                       return utf8_normalize( $string, UNORM_NFKD );
-               elseif( preg_match( '/[\x80-\xff]/', $string ) )
-                       return UtfNormal::NFKD( $string );
-               else
-                       return $string;
-       }
-
-       /**
-        * Load the basic composition data if necessary
-        * @private
-        */
-       static function loadData() {
-               if( !isset( self::$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();
-               $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 );
-                               $i++;
-                       }
-                       if( isset( self::$utfCheckNFC[$c] ) ) {
-                               # If it's NO or MAYBE, bail and do the slow check.
-                               return false;
-                       }
-                       if( isset( self::$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();
-
-                       $utfCheckOrCombining = array_merge( self::$utfCheckNFC, self::$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; ) {
-                               $remaining = $tailBytes[$c = $str{++$i}];
-                               if( $remaining ) {
-                                       # 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( $head );
-                                                       if(
-                                                               # "Overlong sequences" are those that are syntactically
-                                                               # correct but use more UTF-8 bytes than are necessary to
-                                                               # encode a character. Naïve string comparisons can be
-                                                               # tricked into failing to see a match for an ASCII
-                                                               # character, for instance, which can be a security hole
-                                                               # if blacklist checks are being used.
-                                                              ($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();
-
-               return UtfNormal::fastCombiningSort(
-                       UtfNormal::fastDecompose( $string, self::$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( $string ) {
-               if( !isset( self::$utfCompatibilityDecomp ) ) {
-                       require_once( 'UtfNormalDataK.inc' );
-               }
-               return self::fastCombiningSort(
-                       self::fastDecompose( $string, self::$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();
-               $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 );
-                                       $i++;
-                               }
-                               if( isset( self::$utfCombiningClass[$c] ) ) {
-                                       $lastClass = self::$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();
-               $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( $n > 0x80 ) {
-                               if( isset( self::$utfCombiningClass[$c] ) ) {
-                                       # A combining char; see what we can do with it
-                                       $class = self::$utfCombiningClass[$c];
-                                       if( !empty( $startChar ) &&
-                                               $lastClass < $class &&
-                                               $class > 0 &&
-                                               isset( self::$utfCanonicalComp[$pair] ) ) {
-                                               $startChar = self::$utfCanonicalComp[$pair];
-                                               $class = 0;
-                                       } else {
-                                               $combining .= $c;
-                                       }
-                                       $lastClass = $class;
-                                       $lastHangul = 0;
-                                       continue;
-                               }
-                       }
-                       # New start char
-                       if( $lastClass == 0 ) {
-                               if( isset( self::$utfCanonicalComp[$pair] ) ) {
-                                       $startChar = self::$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;
-       }
-       /**
-        * Function to replace some characters that we don't want
-        * but most of the native normalize functions keep.
-        *
-        * @param $string String The string
-        * @return String String with the character codes replaced.
-        */
-       private static function replaceForNativeNormalize( $string ) { 
-               $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 );
-               return $string;
-       }
-}