Minify_CSS_Compressor.php

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<?php
class Minify_CSS_Compressor {

    public static function process($css, $options = array())
    {
        $obj = new Minify_CSS_Compressor($options);
        return $obj->_process($css);
    }
    
    protected $_options = null;
    
    protected $_inHack = false;
    
    
    private function __construct($options) {
        $this->_options = $options;
    }
    
    protected function _process($css)
    {
          if ($this->_options['do_compress']) {
             $css = str_replace("\r\n", "\n", $css);

               // preserve empty comment after '>'
               // http://www.webdevout.net/css-hacks#in_css-selectors
               $css = preg_replace('@>/\\*\\s*\\*/@', '>/*keep*/', $css);

               // preserve empty comment between property and value
               // http://css-discuss.incutio.com/?page=BoxModelHack
               $css = preg_replace('@/\\*\\s*\\*/\\s*:@', '/*keep*/:', $css);
               $css = preg_replace('@:\\s*/\\*\\s*\\*/@', ':/*keep*/', $css);
          }
        // apply callback to all valid comments (and strip out surrounding ws
        $css = preg_replace_callback('@\\s*/\\*([\\s\\S]*?)\\*/\\s*@'
            ,array($this, '_commentCB'), $css);

          if ($this->_options['do_compress']) {
               // remove ws around { } and last semicolon in declaration block
               $css = preg_replace('/\\s*{\\s*/', '{', $css);
               $css = preg_replace('/;?\\s*}\\s*/', '}', $css);

               // remove ws surrounding semicolons
               $css = preg_replace('/\\s*;\\s*/', ';', $css);

               // remove ws around urls
               $css = preg_replace('/
                         url\\(      # url(
                         \\s*
                         ([^\\)]+?)  # 1 = the URL (really just a bunch of non right parenthesis)
                         \\s*
                         \\)         # )
                    /x', 'url($1)', $css);

               // remove ws between rules and colons
               $css = preg_replace('/
                         \\s*
                         ([{;])              # 1 = beginning of block or rule separator 
                         \\s*
                         ([\\*_]?[\\w\\-]+)  # 2 = property (and maybe IE filter)
                         \\s*
                         :
                         \\s*
                         (\\b|[#\'"-])        # 3 = first character of a value
                    /x', '$1$2:$3', $css);
               /*
               // SUPPRIME CAR PLANTE PHP SUR WINDOWS !
               // remove ws in selectors
               $css = preg_replace_callback('/
                         (?:              # non-capture
                              \\s*
                              [^~>+,\\s]+  # selector part
                              \\s*
                              [,>+~]       # combinators
                         )+
                         \\s*
                         [^~>+,\\s]+      # selector part
                         {                # open declaration block
                    /x'
                    ,array($this, '_selectorsCB'), $css);
               */
               // minimize hex colors
               $css = preg_replace('/([^=])#([a-f\\d])\\2([a-f\\d])\\3([a-f\\d])\\4([\\s;\\}])/i'
                    , '$1#$2$3$4$5', $css);

               // remove spaces between font families
               $css = preg_replace_callback('/font-family:([^;}]+)([;}])/'
                    ,array($this, '_fontFamilyCB'), $css);

               $css = preg_replace('/@import\\s+url/', '@import url', $css);

               // replace any ws involving newlines with a single newline
               $css = preg_replace('/[ \\t]*\\n+\\s*/', "\n", $css);

               // separate common descendent selectors w/ newlines (to limit line lengths)
               $css = preg_replace('/([\\w#\\.\\*]+)\\s+([\\w#\\.\\*]+){/', "$1\n$2{", $css);

               // Use newline after 1st numeric value (to limit line lengths).
               $css = preg_replace('/
                    ((?:padding|margin|border|outline):\\d+(?:px|em)?) # 1 = prop : 1st numeric value
                    \\s+
                    /x'
                    ,"$1\n", $css);

               // prevent triggering IE6 bug: http://www.crankygeek.com/ie6pebug/
               $css = preg_replace('/:first-l(etter|ine)\\{/', ':first-l$1 {', $css);
          }
        return trim($css);
    }
    
    protected function _selectorsCB($m)
    {
        // remove ws around the combinators
        return preg_replace('/\\s*([,>+~])\\s*/', '$1', $m[0]);
    }
    
    protected function _commentCB($m)
    {
        $hasSurroundingWs = (trim($m[0]) !== $m[1]);
        $m = $m[1]; 
        // $m is the comment content w/o the surrounding tokens, 
        // but the return value will replace the entire comment.
        if ($m === 'keep') {
            return '/**/';
        }
        if ($m === '" "') {
            // component of http://tantek.com/CSS/Examples/midpass.html
            return '/*" "*/';
        }
        if (preg_match('@";\\}\\s*\\}/\\*\\s+@', $m)) {
            // component of http://tantek.com/CSS/Examples/midpass.html
            return '/*";}}/* */';
        }
        if ($this->_inHack) {
            // inversion: feeding only to one browser
            if (preg_match('@
                    ^/               # comment started like /*/
                    \\s*
                    (\\S[\\s\\S]+?)  # has at least some non-ws content
                    \\s*
                    /\\*             # ends like /*/ or /**/
                @x', $m, $n)) {
                // end hack mode after this comment, but preserve the hack and comment content
                $this->_inHack = false;
                return "/*/{$n[1]}/**/";
            }
        }
        if (substr($m, -1) === '\\') { // comment ends like \*/
            // begin hack mode and preserve hack
            $this->_inHack = true;
            return '/*\\*/';
        }
        if ($m !== '' && $m[0] === '/') { // comment looks like /*/ foo */
            // begin hack mode and preserve hack
            $this->_inHack = true;
            return '/*/*/';
        }
        if ($this->_inHack) {
            // a regular comment ends hack mode but should be preserved
            $this->_inHack = false;
            return '/**/';
        }
        // Issue 107: if there's any surrounding whitespace, it may be important, so 
        // replace the comment with a single space
        return $hasSurroundingWs // remove all other comments
            ? ' '
            : '';
    }
    
    protected function _fontFamilyCB($m)
    {
        // Issue 210: must not eliminate WS between words in unquoted families
        $pieces = preg_split('/(\'[^\']+\'|"[^"]+")/', $m[1], null, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
        $out = 'font-family:';
        while (null !== ($piece = array_shift($pieces))) {
            if ($piece[0] !== '"' && $piece[0] !== "'") {
                $piece = preg_replace('/\\s+/', ' ', $piece);
                $piece = preg_replace('/\\s?,\\s?/', ',', $piece);
            }
            $out .= $piece;
        }
        return $out . $m[2];
    }
}