useless call
[lhc/web/wiklou.git] / includes / normal / UtfNormal.php
index 8626799..c6183b5 100644 (file)
@@ -29,7 +29,7 @@
  *
  * See description of forms at http://www.unicode.org/reports/tr15/
  *
- * @package MediaWiki
+ * @package UtfNormal
  */
 
 /** */
@@ -126,10 +126,24 @@ class UtfNormal {
         * @return string a clean, shiny, normalized UTF-8 string
         */
        function cleanUp( $string ) {
-               if( UtfNormal::quickIsNFCVerify( $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
+               } else {
                        return UtfNormal::NFC( $string );
+               }
        }
 
        /**
@@ -255,106 +269,214 @@ class UtfNormal {
         * Returns true if the string is _definitely_ in NFC.
         * Returns false if not or uncertain.
         * @param string $string a UTF-8 string, altered on output to be valid UTF-8 safe for XML.
-        * @return bool
         */
        function quickIsNFCVerify( &$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;
                
-               UtfNormal::loadData();
-               global $utfCheckNFC, $utfCombiningClass;
-               $len = strlen( $string );
-               $out = '';
-               $state = UTF8_HEAD;
-               $looksNormal = 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;
+                       }
+               }
                
-               $rep = false;
-               $head = 0;
-               for( $i = 0; $i < $len; $i++ ) {
-                       $c = $string{$i};
-                       $n = ord( $c );
-                       if( $state == UTF8_TAIL ) {
-                               if( $n >= 0x80 && $n < 0xc0 ) {
-                                       $sequence .= $c;
-                                       if( --$remaining == 0 ) {
-                                               if( ($sequence >= UTF8_SURROGATE_FIRST
-                                                               && $sequence <= UTF8_SURROGATE_LAST)
-                                                       || ($head == 0xc0 && $sequence <= UTF8_OVERLONG_A)
-                                                       || ($head == 0xc1 && $sequence <= UTF8_OVERLONG_A)
-                                                       || ($head == 0xe0 && $sequence <= UTF8_OVERLONG_B)
-                                                       || ($head == 0xf0 && $sequence <= UTF8_OVERLONG_C)
-                                                       || ($sequence >= UTF8_FDD0 && $sequence <= UTF8_FDEF)
-                                                       || ($sequence == UTF8_FFFE)
-                                                       || ($sequence == UTF8_FFFF)
-                                                       || ($sequence > UTF8_MAX) ) {
-                                                       $out .= UTF8_REPLACEMENT;
-                                                       $state = UTF8_HEAD;
-                                                       continue;
+               # 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.
+               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;
+                                                       }
                                                }
-                                               if( isset( $utfCheckNFC[$sequence] ) ||
-                                                       isset( $utfCombiningClass[$sequence] ) ) {
-                                                       # If it's NO or MAYBE, we'll have to do the slow check.
-                                                       $looksNormal = false;
+                                       } while( --$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;
+                                                       }
                                                }
-                                               $out .= $sequence;
-                                               $state = UTF8_HEAD;
-                                               $head = 0;
                                        }
-                                       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 = '';
                                }
-                               # Not a valid tail byte! DIscard the char we've been building.
-                               #printf ("Invalid '%x' in tail with %d remaining bytes\n", $n, $remaining );
-                               $state = UTF8_HEAD;
-                               $out .= UTF8_REPLACEMENT;
-                       }
-                       if( $n < 0x09 ) {
-                               $out .= UTF8_REPLACEMENT;
-                       } elseif( $n == 0x0a ) {
-                               $out .= $c;
-                       } elseif( $n < 0x0d ) {
-                               $out .= UTF8_REPLACEMENT;
-                       } elseif( $n == 0x0d ) {
-                               # Strip \r silently
-                       } elseif( $n < 0x20 ) {
-                               $out .= UTF8_REPLACEMENT;
-                       } elseif( $n < 0x80 ) {
-                               $out .= $c;
-                       } elseif( $n < 0xc0 ) {
-                               # illegal tail bytes or head byte of overlong sequence
-                               if( $head == 0 ) $out .= UTF8_REPLACEMENT;
-                       } elseif( $n < 0xe0 ) {
-                               $state = UTF8_TAIL;
-                               $remaining = 1;
-                               $sequence = $c;
-                               $head = $n;
-                       } elseif( $n < 0xf0 ) {
-                               $state = UTF8_TAIL;
-                               $remaining = 2;
-                               $sequence = $c;
-                               $head = $n;
-                       } elseif( $n < 0xf8 ) {
-                               $state = UTF8_TAIL;
-                               $remaining = 3;
-                               $sequence = $c;
-                               $head = $n;
-                       } elseif( $n < 0xfc ) {
-                               $state = UTF8_TAIL;
-                               $remaining = 4;
-                               $sequence = $c;
-                               $head = $n;
-                       } elseif( $n < 0xfe ) {
-                               $state = UTF8_TAIL;
-                               $remaining = 5;
-                               $sequence = $c;
-                               $head = $n;
-                       } else {
-                               $out .= UTF8_REPLACEMENT;
                        }
+                       $base += $chunk;
                }
-               if( $state == UTF8_TAIL ) {
-                       $out .= UTF8_REPLACEMENT;
+               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;
                }
-               $string = $out;
                return $looksNormal;
        }
        
@@ -367,7 +489,7 @@ class UtfNormal {
         * @access private
         */
        function NFC( $string ) {
-               return $out = UtfNormal::fastCompose( UtfNormal::NFD( $string ) );
+               return UtfNormal::fastCompose( UtfNormal::NFD( $string ) );
        }
        
        /**
@@ -411,11 +533,11 @@ class UtfNormal {
         * (depending on which decomposition map is passed to us).
         * Input is assumed to be *valid* UTF-8. Invalid code will break.
         * @access private
-        * @param string &$string Valid UTF-8 string
-        * @param array &$map hash of expanded decomposition map
+        * @param string $string Valid UTF-8 string
+        * @param array $map hash of expanded decomposition map
         * @return string a UTF-8 string decomposed, not yet normalized (needs sorting)
         */
-       function fastDecompose( &$string, &$map ) {
+       function fastDecompose( $string, &$map ) {
                UtfNormal::loadData();
                $len = strlen( $string );
                $out = '';
@@ -439,35 +561,35 @@ class UtfNormal {
                        }
                        if( isset( $map[$c] ) ) {
                                $out .= $map[$c];
+                               continue;
                        } else {
                                if( $c >= UTF8_HANGUL_FIRST && $c <= UTF8_HANGUL_LAST ) {
-                                       $out .= UtfNormal::decomposeHangul( $c );
-                               } else {
-                                       $out .= $c;
+                                       # 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;
        }
 
-       /**
-        * Decompose a Hangul syllable character into its constituent jamo.
-        * @access private
-        * @param int $c Unicode code point of the character
-        * @return string a UTF-8 string containing a sequence of jamo
-        */
-       function decomposeHangul( $c ) {
-               $codepoint = utf8ToCodepoint( $c );
-               $index = $codepoint - UNICODE_HANGUL_FIRST;
-               $l = IntVal( $index / UNICODE_HANGUL_NCOUNT );
-               $v = IntVal( ($index % UNICODE_HANGUL_NCOUNT) / UNICODE_HANGUL_TCOUNT);
-               $t = $index % UNICODE_HANGUL_TCOUNT;
-               $out = codepointToUtf8( $l + UNICODE_HANGUL_LBASE );
-               $out .= codepointToUtf8( $v + UNICODE_HANGUL_VBASE );
-               if( $t ) $out .= codepointToUtf8( $t + UNICODE_HANGUL_TBASE );
-               return $out;
-       }
-       
        /**
         * Sorts combining characters into canonical order. This is the
         * final step in creating decomposed normal forms D and KD.
@@ -478,16 +600,14 @@ class UtfNormal {
        function fastCombiningSort( $string ) {
                UtfNormal::loadData();
                global $utfCombiningClass;
-               $replacedCount = 1;
-               while( $replacedCount > 0 ) {
-                       $replacedCount = 0;
-                       $len = strlen( $string );
-                       $out = '';
-                       $lastClass = -1;
-                       $lastChar = '';
-                       for( $i = 0; $i < $len; $i++ ) {
-                               $c = $string{$i};
-                               $n = ord( $c );
+               $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;
@@ -498,25 +618,25 @@ class UtfNormal {
                                        $c = substr( $string, $i, 2 );
                                        $i++;
                                }
-                               $class = isset( $utfCombiningClass[$c] ) ? $utfCombiningClass[$c] : 0;
-                               if( $lastClass == -1 ) {
-                                       # First one
-                                       $lastChar = $c;
-                                       $lastClass = $class;
-                               } elseif( $lastClass > $class && $class > 0 ) {
-                                       # Swap -- put this one on the stack
-                                       $out .= $c;
-                                       $replacedCount++;
-                               } else {
-                                       $out .= $lastChar;
-                                       $lastChar = $c;
-                                       $lastClass = $class;
+                               if( isset( $utfCombiningClass[$c] ) ) {
+                                       $lastClass = $utfCombiningClass[$c];
+                                       @$combiners[$lastClass] .= $c;
+                                       continue;
                                }
                        }
-                       $out .= $lastChar;
-                       $string = $out;
+                       if( $lastClass ) {
+                               ksort( $combiners );
+                               $out .= implode( '', $combiners );
+                               $combiners = array();
+                       }
+                       $out .= $c;
+                       $lastClass = 0;
+               }
+               if( $lastClass ) {
+                       ksort( $combiners );
+                       $out .= implode( '', $combiners );
                }
-               return $string;
+               return $out;
        }
 
        /**
@@ -532,12 +652,23 @@ class UtfNormal {
                $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 >= 0xf0 ) {
+                       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 ) {
@@ -547,55 +678,100 @@ class UtfNormal {
                                $c = substr( $string, $i, 2 );
                                $i++;
                        }
-                       $class = isset( $utfCombiningClass[$c] ) ? $utfCombiningClass[$c] : 0;
                        $pair = $startChar . $c;
-                       if( empty( $utfCombiningClass[$c] ) ) {
-                               # New start char
-                               if( $lastClass == 0 && isset( $utfCanonicalComp[$pair] ) ) {
-                                       $startChar = $utfCanonicalComp[$pair];
-                               } elseif( $lastClass == 0 &&
-                                         $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;
-                                       $hangulPoint = UNICODE_HANGUL_FIRST +
-                                               UNICODE_HANGUL_TCOUNT *
-                                               (UNICODE_HANGUL_VCOUNT * $lIndex + $vIndex);
-                                       $startChar = codepointToUtf8( $hangulPoint );
-                               } elseif( $lastClass == 0 &&
-                                         $c >= UTF8_HANGUL_TBASE &&
-                                         $c <= UTF8_HANGUL_TEND &&
-                                         $startChar >= UTF8_HANGUL_FIRST &&
-                                         $startChar <= UTF8_HANGUL_LAST ) {
-                                       $tIndex = utf8ToCodepoint( $c ) - UNICODE_HANGUL_TBASE;
-                                       $hangulPoint = utf8ToCodepoint( $startChar ) + $tIndex;
-                                       $startChar = codepointToUtf8( $hangulPoint );
-                               } else {
-                                       $out .= $startChar;
-                                       $out .= $combining;
-                                       $startChar = $c;
-                                       $combining = '';
+                       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;
                                }
-                       } else {
-                               # A combining char; see what we can do with it
-                               if( !empty( $startChar ) &&
-                                       $lastClass < $class &&
-                                       $class > 0 &&
-                                       isset( $utfCanonicalComp[$pair] ) ) {
+                       }
+                       # New start char
+                       if( $lastClass == 0 ) {
+                               if( isset( $utfCanonicalComp[$pair] ) ) {
                                        $startChar = $utfCanonicalComp[$pair];
-                                       $class = 0;
-                               } else {
-                                       $combining .= $c;
+                                       $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;
+                                       }
                                }
                        }
-                       $lastClass = $class;
+                       $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.