Compressing CSS in PHP (no comments or whitespace)

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I was searching for methods to remove comments and whitespace from CSS files in PHP and I found this article (3 ways to compress CSS files using PHP).

The article suggests this code by Reinhold Weber, which I thought was a pretty good place to start:

<?php
  header('Content-type: text/css');
  ob_start("compress");
  function compress($buffer) {
    /* remove comments */
    $buffer = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!', '', $buffer);
    /* remove tabs, spaces, newlines, etc. */
    $buffer = str_replace(array("\r\n", "\r", "\n", "\t", '  ', '    ', '    '), '', $buffer);
    return $buffer;
  }

  /* your css files */
  include('master.css');
  include('typography.css');
  include('grid.css');
  include('print.css');
  include('handheld.css');

  ob_end_flush();
?>

Later I found css_strip_whitespace by nyctimus in the documentation for the PHP method strip_whitespace. It looks like this:

function css_strip_whitespace($css)
{
  $replace = array(
    "#/\*.*?\*/#s" => "",  // Strip C style comments.
    "#\s\s+#"      => " ", // Strip excess whitespace.
  );
  $search = array_keys($replace);
  $css = preg_replace($search, $replace, $css);

  $replace = array(
    ": "  => ":",
    "; "  => ";",
    " {"  => "{",
    " }"  => "}",
    ", "  => ",",
    "{ "  => "{",
    ";}"  => "}", // Strip optional semicolons.
    ",\n" => ",", // Don't wrap multiple selectors.
    "\n}" => "}", // Don't wrap closing braces.
    "} "  => "}\n", // Put each rule on it's own line.
  );
  $search = array_keys($replace);
  $css = str_replace($search, $replace, $css);

  return trim($css);
}

The latter function is the one that I used, and I’m quite happy with it. I’ve been working on HTML and JavaScript compressors too, and those are much more difficult file formats to deal with than CSS.

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