diff --git a/README.mdown b/README.mdown
index 23d46a5..9b3ce86 100644
--- a/README.mdown
+++ b/README.mdown
@@ -40,7 +40,13 @@ $html = '<div>
         text
     </p> 
 </div>';
+
+// shortcut. retrun minify html
 $minify = HTMLMinify::minify($html);
+
+// detail
+$HTMLMinify = new HTMLMinify($html);
+$minify = $HTMLMinify->process();
 ```
 
 output html
diff --git a/composer.json b/composer.json
index d812387..5bf86cb 100644
--- a/composer.json
+++ b/composer.json
@@ -18,8 +18,7 @@
         }
     ],
     "require": {
-        "php": ">=5.3.0",
-        "composer/installers": "*"
+        "php": ">=5.3.0"
     },
     "require-dev": {
         "satooshi/php-coveralls": "dev-master"
diff --git a/src/zz/Html/HTMLMinify.php b/src/zz/Html/HTMLMinify.php
index 362d196..e9c134e 100644
--- a/src/zz/Html/HTMLMinify.php
+++ b/src/zz/Html/HTMLMinify.php
@@ -8,8 +8,6 @@
 namespace zz\Html;
 
 class HTMLMinify {
-    const ENCODING = 'UTF-8';
-
     const DOCTYPE_HTML4 = 'HTML4.01';
     const DOCTYPE_XHTML1 = 'XHTML1.0';
     const DOCTYPE_HTML5 = 'html5';
@@ -226,7 +224,7 @@ public function __construct($html, $options = array()) {
      *
      * 'excludeComment'
      *     example : <!--nocache-->content</--nocache-->
-     *     array()(default)             => content
+     *     array('/<!--\/?nocache-->/')(default)             => content
      *     array('/<!--\/?nocache-->/') => <!--nocache-->content</--nocache-->
      *
      * 'removeDuplicateAttribute'
@@ -389,60 +387,62 @@ protected function beforeFilter() {
     protected function removeWhitespaceFromComment() {
         $tokens = $this->tokens;
         $regexps = $this->options['excludeComment'];
-
-        for ($i = 0, $len = count($tokens); $i < $len; $i++) {
+        $HTMLTokenStartTag = HTMLToken::StartTag;
+        $HTMLTokenComment = HTMLToken::Comment;
+        $HTMLTokenCharacter = HTMLToken::Character;
+        $HTMLNamesScriptTag = HTMLNames::scriptTag;
+        $HTMLNamesStyleTag = HTMLNames::styleTag;
+        $removes = array();
+        $combineIndex = null;
+
+        $len = count($tokens);
+        for ($i = 0; $i < $len; $i++) {
             $token = $tokens[$i];
             $type = $token->getType();
-            if ($type === HTMLToken::StartTag) {
+            if ($type === $HTMLTokenStartTag) {
+                $combineIndex = null;
                 $tagName = $token->getTagName();
-                if ($tagName === HTMLNames::scriptTag || $tagName === HTMLNames::styleTag) {
+                if ($tagName === $HTMLNamesScriptTag || $tagName === $HTMLNamesStyleTag) {
                     $i++;
-                    continue;
                 }
-            } else if ($this->_isConditionalComment($token)) {
+                continue;
+            } else if ($type === $HTMLTokenCharacter) {
+                if ($combineIndex > 0) {
+                    $tokens[$combineIndex]->setData($tokens[$combineIndex] . $token);
+                    $removes[] = $i;
+                }
+                continue;
+            } else if ($type !== $HTMLTokenComment) {
+                $combineIndex = null;
                 continue;
             }
-            if ($type !== HTMLToken::Comment) {
+
+            $comment = $token->getData();
+            if ($this->_isConditionalComment($comment)) {
+                $combineIndex = null;
                 continue;
             }
             if ($regexps) {
-                $comment = $token->getData();
                 foreach ($regexps as $regexp) {
                     if (preg_match($regexp, $comment)) {
+                        $combineIndex = null;
                         continue 2;
                     }
                 }
             }
-
-            unset($tokens[$i]);
-            $tokens = array_merge($tokens, array());
-            $len = count($tokens);
-            $i--;
+            $combineIndex = $i - 1;
+            $removes[] = $i;
         }
 
-        /**
-         * @var HTMLToken[] $tokens
-         */
-        $tokens = array_merge($tokens, array());
+        foreach ($removes as $remove) {
+            unset($tokens[$remove]);
+        }
 
-        // combine chars
-        for ($i = 1, $len = count($tokens); $i < $len; $i++) {
-            $token = $tokens[$i];
-            if ($token->getType() !== HTMLToken::Character) {
-                continue;
-            }
-            $token_before = $tokens[$i - 1];
-            if ($token_before->getType() !== HTMLToken::Character) {
-                continue;
-            }
-            $tokens[$i]->setData($token_before . $token->getData());
-            unset($tokens[$i - 1]);
-            $len = count($tokens);
-            $tokens = array_merge($tokens, array());
-            $i--;
+        if ($len !== count($tokens)) {
+            $tokens = array_merge($tokens,array());
         }
-        $tokens = array_merge($tokens, array());
         $this->tokens = $tokens;
+        return true;
     }
 
     protected function isInlineTag($tag) {
@@ -470,22 +470,24 @@ protected function removeWhitespaceFromCharacter() {
             $token = $tokens[$i];
             $type = $token->getType();
             if ($type === HTMLToken::StartTag) {
-                $isBeforeInline = $this->isInlineTag($token->getTagName());
-                switch ($token->getTagName()) {
+                $tagName = $token->getName();
+                $isBeforeInline = $this->isInlineTag($tagName);
+                switch ($tagName) {
                     case HTMLNames::scriptTag:
                     case HTMLNames::styleTag:
                     case HTMLNames::textareaTag:
                     case HTMLNames::preTag:
                         $isEditable = false;
-                        $uneditableTag = $token->getTagName();
+                        $uneditableTag = $tagName;
                         continue 2;
                         break;
                     default:
                         break;
                 }
             } else if ($type === HTMLToken::EndTag) {
-                $isBeforeInline = $this->isInlineTag($token->getTagName());
-                if (!$isEditable && $token->getTagName() === $uneditableTag) {
+                $tagName = $token->getName();
+                $isBeforeInline = $this->isInlineTag($tagName);
+                if (!$isEditable && $tagName === $uneditableTag) {
                     $uneditableTag = null;
                     $isEditable = true;
                     continue;
@@ -535,12 +537,12 @@ protected function _removeWhitespaceFromCharacter($characters) {
         $compactCharacters = '';
         $hasWhiteSpace = false;
 
-        for ($i = 0, $len = mb_strlen($characters, static::ENCODING); $i < $len; $i++) {
-            $char = mb_substr($characters, $i, 1, static::ENCODING);
+        for ($i = 0, $len = strlen($characters); $i < $len; $i++) {
+            $char = $characters[$i];
             if ($char === "\x0A") {
                 // remove before whitespace char
                 if ($hasWhiteSpace) {
-                    $compactCharacters = mb_substr($compactCharacters, 0, -1, static::ENCODING);
+                    $compactCharacters = substr($compactCharacters, 0, -1);
                 }
                 $compactCharacters .= $char;
                 $hasWhiteSpace = true;
@@ -567,7 +569,7 @@ protected function optimizeStartTagAttributes() {
             }
 
             $attributes_old = $token->getAttributes();
-            $attributes_new = array();
+            $attributes_new =array();
             $attributes_name = array();
 
             foreach ($attributes_old as $attribute) {
@@ -586,15 +588,10 @@ protected function optimizeStartTagAttributes() {
     /**
      * downlevel-hidden : <!--[if expression]> HTML <![endif]-->
      * downlevel-revealed : <![if expression]> HTML <![endif]>
-     * @param HTMLToken $token
+     * @param string $comment
      * @return bool
      */
-    protected function _isConditionalComment(HTMLToken $token) {
-        if ($token->getType() !== HTMLToken::Comment) {
-            return false;
-        }
-
-        $comment = $this->_buildElement($token);
+    protected function _isConditionalComment($comment) {
         $pattern = '/\A<!(?:--)?\[if [^\]]+\]>/s';
         if (preg_match($pattern, $comment)) {
             return true;
diff --git a/src/zz/Html/HTMLToken.php b/src/zz/Html/HTMLToken.php
index 76ae0e3..67bbbd1 100644
--- a/src/zz/Html/HTMLToken.php
+++ b/src/zz/Html/HTMLToken.php
@@ -235,7 +235,8 @@ public function setState($states) {
     }
 
     public function getTagName() {
-        if ($this->getType() !== static::StartTag && $this->getType() !== static::EndTag) {
+        $type = $this->getType();
+        if ($type !== static::StartTag && $type !== static::EndTag) {
             return false;
         }
         return $this->getName();
diff --git a/src/zz/Html/HTMLTokenizer.php b/src/zz/Html/HTMLTokenizer.php
index e97316a..30a1cdf 100644
--- a/src/zz/Html/HTMLTokenizer.php
+++ b/src/zz/Html/HTMLTokenizer.php
@@ -175,6 +175,7 @@ public function getState() {
     }
 
     /**
+     * @throws \InvalidArgumentException
      * @return HtmlToken[]
      */
     public function tokenizer() {
@@ -195,12 +196,13 @@ public function tokenizer() {
             $startState = $this->_startState;
             // In other than `DataState`, `nextToken` return the type of Character, it contains the type of EndTag.
             // SegmentedString go back to the end of the type of Character position.
-            if ($this->_Token->getType() === HTMLToken::Character && $this->_bufferedEndTagName !== '' && ($startState === static::RAWTEXTState || $startState === static::RCDATAState || $startState === static::ScriptDataState)) {
+            $type = $this->_Token->getType();
+            if ($type === HTMLToken::Character && $this->_bufferedEndTagName !== '' && ($startState === static::RAWTEXTState || $startState === static::RCDATAState || $startState === static::ScriptDataState)) {
                 $length = strlen($this->_Token->getData());
 
                 // HTMLToken::Character
                 $this->_buffer = array_slice($this->_buffer, 0, $length);
-                $this->_compactBuffer($startPos, $startPos + $length);
+                $this->_compactBuffer($startPos, $startPos + $length, $type);
                 $token = $this->_Token;
                 $this->_tokens[] = $token;
 
@@ -208,11 +210,11 @@ public function tokenizer() {
                 $this->_SegmentedString->seek($startPos + $length);
                 $this->_state = $startState;
             } else {
-                $this->_compactBuffer($startPos, $endPos);
+                $this->_compactBuffer($startPos, $endPos, $type);
                 $token = $this->_Token;
                 $this->_tokens[] = $token;
                 // FIXME: The tokenizer should do this work for us.
-                if ($this->_Token->getType() === HTMLToken::StartTag) {
+                if ($type === HTMLToken::StartTag) {
                     $this->_updateStateFor($token->getTagName());
                 } else {
                     $this->_state = static::DataState;
@@ -239,7 +241,7 @@ public function getTokensAsArray() {
         return $result;
     }
 
-    protected function _compactBuffer($startPos, $endPos) {
+    protected function _compactBuffer($startPos, $endPos, $type) {
         $compactBuffer = array();
         $before = static::kEndOfFileMarker;
         $html = $this->_SegmentedString->substr($startPos, $endPos - $startPos);
@@ -248,7 +250,7 @@ protected function _compactBuffer($startPos, $endPos) {
                 $before = $compactBuffer[$i] = $state;
             }
         }
-        switch ($this->_Token->getType()) {
+        switch ($type) {
             case HTMLToken::Uninitialized:
             case HTMLToken::EndOfFile:
             case HTMLToken::Character:
@@ -260,7 +262,7 @@ protected function _compactBuffer($startPos, $endPos) {
         if ($this->_debug) {
             $this->_Token->setHtmlOrigin($html);
             $this->_Token->setState($compactBuffer);
-        } else if ($this->_Token->getType() === HTMLToken::DOCTYPE) {
+        } else if ($type === HTMLToken::DOCTYPE) {
             $this->_Token->setHtmlOrigin($html);
         }
         $this->_Token->clean();
@@ -360,10 +362,10 @@ protected function nextToken(SegmentedString $source) {
                         $this->_HTML_ADVANCE_TO(static::MarkupDeclarationOpenState);
                     } else if ($char === '/') {
                         $this->_HTML_ADVANCE_TO(static::EndTagOpenState);
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_Token->beginStartTag(strtolower($char));
                         $this->_HTML_ADVANCE_TO(static::TagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_Token->beginStartTag(strtolower($char));
                         $this->_HTML_ADVANCE_TO(static::TagNameState);
                     } else if ($char === '?') {
@@ -380,10 +382,10 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::EndTagOpenState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_Token->beginEndTag(strtolower($char));
                         $this->_HTML_ADVANCE_TO(static::TagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_Token->beginEndTag(strtolower($char));
                         $this->_HTML_ADVANCE_TO(static::TagNameState);
                     } else if ($char === '>') {
@@ -407,7 +409,7 @@ protected function nextToken(SegmentedString $source) {
                         $this->_HTML_ADVANCE_TO(static::SelfClosingStartTagState);
                     } else if ($char === '>') {
                         return $this->_emitAndResumeIn();
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_Token->appendToName(strtolower($char));
                         $this->_HTML_ADVANCE_TO(static::TagNameState);
                     } else if ($char === static::kEndOfFileMarker) {
@@ -430,11 +432,11 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::RCDATAEndTagOpenState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::RCDATAEndTagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= $char;
                         $this->_HTML_ADVANCE_TO(static::RCDATAEndTagNameState);
@@ -446,11 +448,11 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::RCDATAEndTagNameState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::RCDATAEndTagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= $char;
                         $this->_HTML_ADVANCE_TO(static::RCDATAEndTagNameState);
@@ -499,11 +501,11 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::RAWTEXTEndTagOpenState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::RAWTEXTEndTagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= $char;
                         $this->_HTML_ADVANCE_TO(static::RAWTEXTEndTagNameState);
@@ -515,11 +517,11 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::RAWTEXTEndTagNameState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::RAWTEXTEndTagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= $char;
                         $this->_HTML_ADVANCE_TO(static::RAWTEXTEndTagNameState);
@@ -572,11 +574,11 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::ScriptDataEndTagOpenState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEndTagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= $char;
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEndTagNameState);
@@ -588,11 +590,11 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::ScriptDataEndTagNameState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEndTagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= $char;
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEndTagNameState);
@@ -700,13 +702,13 @@ protected function nextToken(SegmentedString $source) {
                     if ($char === '/') {
                         $this->_temporaryBuffer = '';
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEscapedEndTagOpenState);
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_bufferCharacter('<');
                         $this->_bufferCharacter($char);
                         $this->_temporaryBuffer = '';
                         $this->_temporaryBuffer = strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::ScriptDataDoubleEscapeStartState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_bufferCharacter('<');
                         $this->_bufferCharacter($char);
                         $this->_temporaryBuffer = '';
@@ -719,11 +721,11 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::ScriptDataEscapedEndTagOpenState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEscapedEndTagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= $char;
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEscapedEndTagNameState);
@@ -735,11 +737,11 @@ protected function nextToken(SegmentedString $source) {
                     break;
 
                 case static::ScriptDataEscapedEndTagNameState:
-                    if ($this->_isASCIIUpper($char)) {
+                    if (ctype_upper($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEscapedEndTagNameState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_temporaryBuffer .= $char;
                         $this->_bufferedEndTagName .= $char;
                         $this->_HTML_ADVANCE_TO(static::ScriptDataEscapedEndTagNameState);
@@ -780,11 +782,11 @@ protected function nextToken(SegmentedString $source) {
                         } else {
                             $this->_HTML_ADVANCE_TO(static::ScriptDataEscapedState);
                         }
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_bufferCharacter($char);
                         $this->_temporaryBuffer .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::ScriptDataDoubleEscapeStartState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_bufferCharacter($char);
                         $this->_temporaryBuffer .= $char;
                         $this->_HTML_ADVANCE_TO(static::ScriptDataDoubleEscapeStartState);
@@ -861,11 +863,11 @@ protected function nextToken(SegmentedString $source) {
                         } else {
                             $this->_HTML_ADVANCE_TO(static::ScriptDataDoubleEscapedState);
                         }
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_bufferCharacter($char);
                         $this->_temporaryBuffer .= strtolower($char);
                         $this->_HTML_ADVANCE_TO(static::ScriptDataDoubleEscapeEndState);
-                    } else if ($this->_isASCIILower($char)) {
+                    } else if (ctype_lower($char)) {
                         $this->_bufferCharacter($char);
                         $this->_temporaryBuffer .= $char;
                         $this->_HTML_ADVANCE_TO(static::ScriptDataDoubleEscapeEndState);
@@ -881,7 +883,7 @@ protected function nextToken(SegmentedString $source) {
                         $this->_HTML_ADVANCE_TO(static::SelfClosingStartTagState);
                     } else if ($char === '>') {
                         return $this->_emitAndResumeIn();
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_Token->addNewAttribute();
                         $this->_Token->beginAttributeName($source->numberOfCharactersConsumed());
                         $this->_Token->appendToAttributeName(strtolower($char));
@@ -913,7 +915,7 @@ protected function nextToken(SegmentedString $source) {
                     } else if ($char === '>') {
                         $this->_Token->endAttributeName($source->numberOfCharactersConsumed());
                         return $this->_emitAndResumeIn();
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_Token->appendToAttributeName(strtolower($char));
                         $this->_HTML_ADVANCE_TO(static::AttributeNameState);
                     } else if ($char === static::kEndOfFileMarker) {
@@ -938,7 +940,7 @@ protected function nextToken(SegmentedString $source) {
                         $this->_HTML_ADVANCE_TO(static::BeforeAttributeValueState);
                     } else if ($char === '>') {
                         return $this->_emitAndResumeIn();
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_Token->addNewAttribute();
                         $this->_Token->beginAttributeName($source->numberOfCharactersConsumed());
                         $this->_Token->appendToAttributeName(strtolower($char));
@@ -1265,7 +1267,7 @@ protected function nextToken(SegmentedString $source) {
                 case static::BeforeDOCTYPENameState:
                     if ($this->_isTokenizerWhitespace($char)) {
                         $this->_HTML_ADVANCE_TO(static::BeforeDOCTYPENameState);
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_Token->beginDOCTYPE(strtolower($char));
                         $this->_HTML_ADVANCE_TO(static::DOCTYPENameState);
                     } else if ($char === '>') {
@@ -1289,7 +1291,7 @@ protected function nextToken(SegmentedString $source) {
                         $this->_HTML_ADVANCE_TO(static::AfterDOCTYPENameState);
                     } else if ($char === '>') {
                         return $this->_emitAndResumeIn();
-                    } else if ($this->_isASCIIUpper($char)) {
+                    } else if (ctype_upper($char)) {
                         $this->_Token->appendToName(strtolower($char));
                         $this->_HTML_ADVANCE_TO(static::DOCTYPENameState);
                     } else if ($char === static::kEndOfFileMarker) {
@@ -1636,14 +1638,6 @@ protected function _notImplemented() {
         // logger
     }
 
-    protected function _isASCIIUpper($char) {
-        return preg_match('/\A[A-Z]\Z/', $char);
-    }
-
-    protected function _isASCIILower($char) {
-        return preg_match('/\A[a-z]\Z/', $char);
-    }
-
     protected function _temporaryBufferIs($expectedString) {
         return $this->_vectorEqualsString($this->_temporaryBuffer, $expectedString);
     }
@@ -1690,15 +1684,15 @@ protected function _emitAndResumeIn() {
         return true;
     }
 
-    protected function _flushEmitAndResumeIn($source, $state) {
+    protected function _flushEmitAndResumeIn(SegmentedString $source, $state) {
         // m_state = state;
         $this->_state = $state;
         $this->_flushBufferedEndTag($source);
         return true;
     }
 
-    protected function _flushBufferedEndTag($source) {
-        $this->_SegmentedString->advance();
+    protected function _flushBufferedEndTag(SegmentedString $source) {
+        $source->advance();
         if ($this->_Token->getType() === HTMLToken::Character) {
             return true;
         }
diff --git a/src/zz/Html/SegmentedString.php b/src/zz/Html/SegmentedString.php
index 2dbc0fa..6989989 100644
--- a/src/zz/Html/SegmentedString.php
+++ b/src/zz/Html/SegmentedString.php
@@ -48,7 +48,11 @@ public function __construct($str) {
      * @return bool|string
      */
     public function  getCurrentChar() {
-        return substr($this->str, $this->i, 1);
+        $i = $this->i;
+        if ($this->len <= $i) {
+            return false;
+        }
+        return $this->str[$i];
     }
 
     public function advance() {
@@ -78,6 +82,8 @@ public function substr($startPos, $length) {
 
     /**
      * @param int $offset
+     * @param int $whence
+     * @throws \InvalidArgumentException
      * @return bool
      */
     public function seek($offset, $whence = self::begin) {