function CSSmin::processDataUrls

Searches & replaces all data urls with tokens before we start compressing, to avoid performance issues running some of the subsequent regexes against large string chunks.

Parameters

string $css:

Return value

string

1 call to CSSmin::processDataUrls()

CSSmin::run in advagg_css_compress/yui/CSSMin.inc

Minifies a string of CSS

File

advagg_css_compress/yui/CSSMin.inc, line 574

Class

CSSmin

Code

private function processDataUrls($css) {
    // Leave data urls alone to increase parse performance.
    $maxIndex = strlen($css) - 1;
    $appenIndex = $index = $lastIndex = $offset = 0;
    $sb = array();
    $pattern = '/url\\(\\s*(["\']?)data:/i';
    // Since we need to account for non-base64 data urls, we need to handle
    // ' and ) being part of the data string. Hence switching to indexOf,
    // to determine whether or not we have matching string terminators and
    // handling sb appends directly, instead of using matcher.append* methods.
    while (preg_match($pattern, $css, $m, 0, $offset)) {
        $index = $this->indexOf($css, $m[0], $offset);
        $lastIndex = $index + strlen($m[0]);
        $startIndex = $index + 4;
        // "url(".length()
        $endIndex = $lastIndex - 1;
        $terminator = $m[1];
        // ', " or empty (not quoted)
        $terminatorFound = false;
        if (strlen($terminator) === 0) {
            $terminator = ')';
        }
        while ($terminatorFound === false && $endIndex + 1 <= $maxIndex) {
            $endIndex = $this->indexOf($css, $terminator, $endIndex + 1);
            // endIndex == 0 doesn't really apply here
            if ($endIndex > 0 && substr($css, $endIndex - 1, 1) !== '\\') {
                $terminatorFound = true;
                if (')' !== $terminator) {
                    $endIndex = $this->indexOf($css, ')', $endIndex);
                }
            }
        }
        // Enough searching, start moving stuff over to the buffer
        $sb[] = $this->strSlice($css, $appenIndex, $index);
        if ($terminatorFound) {
            $token = $this->strSlice($css, $startIndex, $endIndex);
            // Remove all spaces only for base64 encoded URLs.
            $token = preg_replace_callback('/.+base64,.+/s', array(
                $this,
                'removeSpacesFromDataUrls',
            ), trim($token));
            $preservedTokenPlaceholder = $this->registerPreservedToken($token);
            $sb[] = 'url(' . $preservedTokenPlaceholder . ')';
            $appenIndex = $endIndex + 1;
        }
        else {
            // No end terminator found, re-add the whole match. Should we throw/warn here?
            $sb[] = $this->strSlice($css, $index, $lastIndex);
            $appenIndex = $lastIndex;
        }
        $offset = $lastIndex;
    }
    $sb[] = $this->strSlice($css, $appenIndex);
    return implode('', $sb);
}