/**
* Minify a CSS string
*
* @param string $css
*
* @param array $options To enable URL rewriting, set the value
* for key 'prependRelativePath'.
*
* @return string
*/
protected static function _minify($css, $options)
{
$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*/', $css);
// apply callback to all valid comments (and strip out surrounding ws
self::$_inHack = false;
$css = preg_replace_callback('@\\s*/\\*([\\s\\S]*?)\\*/\\s*@', array(self::$className, '_commentCB'), $css);
// 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);
// remove ws in selectors
$css = preg_replace_callback('/
(?: # non-capture
\\s*
[^~>+,\\s]+ # selector part
\\s*
[,>+~] # combinators
)+
\\s*
[^~>+,\\s]+ # selector part
{ # open declaration block
/x', array(self::$className, '_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
$css = preg_replace_callback('/font-family:([^;}]+)([;}])/', array(self::$className, '_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);
$rewrite = false;
if (isset($options['prependRelativePath'])) {
self::$_tempPrepend = $options['prependRelativePath'];
$rewrite = true;
} elseif (isset($options['currentDir'])) {
self::$_tempCurrentDir = $options['currentDir'];
$rewrite = true;
}
if ($rewrite) {
$css = preg_replace_callback('/@import\\s+([\'"])(.*?)[\'"]/', array(self::$className, '_urlCB'), $css);
$css = preg_replace_callback('/url\\(\\s*([^\\)\\s]+)\\s*\\)/', array(self::$className, '_urlCB'), $css);
}
self::$_tempPrepend = self::$_tempCurrentDir = '';
return trim($css);
}
