<?php
//built with help from the amazing people on stackoverflow
//http://stackoverflow.com/questions/17928427/regular-expression-to-not-match-something-in-quotes/17928889

/////////////////////////////////////////////////////////////////////
$contents = 'img[style*="float: left"]
img: [style*="float: left"]
img( [style*="float: left"]';
echo drupal_load_stylesheet_content($contents, TRUE);
////////////////////////////////////////////////////////////////////


function drupal_load_stylesheet_content($contents, $optimize = FALSE) {
  // Remove multiple charset declarations for standards compliance (and fixing Safari problems).
  $contents = preg_replace('/^@charset\s+[\'"](\S*)\b[\'"];/i', '', $contents);

  if ($optimize) {
    // Perform some safe CSS optimizations.
    // Regexp to match comment blocks.
    $comment     = '/\*[^*]*\*+(?:[^/*][^*]*\*+)*/';
    // Regexp to match double quoted strings.
    $double_quot = '"[^"\\\\]*(?:\\\\.[^"\\\\]*)*"';
    // Regexp to match single quoted strings.
    $single_quot = "'[^'\\\\]*(?:\\\\.[^'\\\\]*)*'";
    // Strip all comment blocks, but keep double/single quoted strings.
    $contents = preg_replace(
      "<($double_quot|$single_quot)|$comment>Ss",
      "$1",
      $contents
    );
    // Remove certain whitespace.
    // There are different conditions for removing leading and trailing
    // whitespace.
    // @see http://p...content-available-to-author-only...p.net/manual/en/regexp.reference.subpatterns.php
    $contents = preg_replace('<
      # Strip leading and trailing whitespace.
        \s*([@{};,])\s*
      # Strip only leading whitespace from:
      # - Closing parenthesis: Retain "@media (bar) and foo".
      | \s+([\)])
      # Strip only trailing whitespace from:
      # - Opening parenthesis: Retain "@media (bar) and foo".
      | ([\(])\s+
    >xS',
      // Only one of the three capturing groups will match, so its reference
      // will contain the wanted value and the references for the
      // two non-matching groups will be replaced with empty strings.
      '$1$2$3',
      $contents
    );

    //Strip only trailing whitespace from colons unless that colon appears within double quotes
    $contents = preg_replace_callback('/"[^"]*"|([:])\s+/ims',
        function ($matches) {
            if (array_key_exists (1, $matches)) {
                return $matches[1] ;
            }
            return $matches[0];
        },
        $contents
    );

    // End the file with a new line.
    $contents = trim($contents);
    $contents .= "\n";
  }

  // Replaces @import commands with the actual stylesheet content.
  // This happens recursively but omits external files.
  $contents = preg_replace_callback('/@import\s*(?:url\(\s*)?[\'"]?(?![a-z]+:)([^\'"\()]+)[\'"]?\s*\)?\s*;/', '_drupal_load_stylesheet', $contents);
  return $contents;
}


?>