Trim.inc

<?php


/**
 * CSS Compressor [VERSION]
 * [DATE]
 * Corey Hart @ http://www.codenothing.com
 */
class CSSCompression_Trim {
    
    /**
     * Trim Patterns
     *
     * @class Control: Compression Controller
     * @param (array) options: Reference to options
     * @param (regex) rcmark: Marking point when traversing through sheet for comments
     * @param (regex) rendcomment: Finds the ending comment point
     * @param (regex) rendquote: Finds the ending quote point
     * @param (regex) rendsinglequote: Finds the ending single quote point
     * @param (array) rescape: Array of patterns of groupings that should be escaped
     * @param (array) trimmings: Stylesheet trimming patterns/replacements
     * @param (array) escaped: Array of characters that need to be escaped
     */
    private $Control;
    private $options = array();
    private $rcmark = "/((?<!\\\\)\\/\\*|(?<!\\\\)\"|(?<!\\\\)')/";
    private $rendcomment = "/\\*\\//";
    private $rendquote = "/(?<!\\\\)\"/";
    private $rendsinglequote = "/(?<!\\\\)'/";
    private $rescape = array(
        "/(url\\()([^'\"].*?)(\\))/is",
        "/((?<!\\\\)\")(.*?)((?<!\\\\)\")/s",
        "/((?<!\\\\)')(.*?)((?<!\\\\)')/s",
    );
    private $trimmings = array(
        'patterns' => array(
            "/(?<!\\\\)(\\s+)?(?<!\\\\)([!,{};>\\~\\+\\/])(?<!\\\\)(\\s+)?/s",
            // Remove un-needed spaces around special characters
"/url\\((?<!\\\\)\"(.*?)(?<!\\\\)\"\\)/is",
            // Remove quotes from urls
"/url\\((?<!\\\\)'(.*?)(?<!\\\\)'\\)/is",
            // Remove single quotes from urls
"/url\\((.*?)\\)/is",
            // Lowercase url wrapper
"/(?<!\\\\);{2,}/",
            // Remove unecessary semi-colons
"/(?<!\\\\)\\s+/s",
        ),
        'replacements' => array(
            '$2',
            'url($1)',
            'url($1)',
            'url($1)',
            ';',
            ' ',
        ),
    );
    private $escaped = array(
        'search' => array(
            ":",
            ";",
            "}",
            "{",
            "@",
            "!",
            ",",
            ">",
            "+",
            "~",
            "/",
            "*",
            ".",
            "=",
            "#",
            "\r",
            "\n",
            "\t",
            " ",
        ),
        'replace' => array(
            "\\:",
            "\\;",
            "\\}",
            "\\{",
            "\\@",
            "\\!",
            "\\,",
            "\\>",
            "\\+",
            "\\~",
            "\\/",
            "\\*",
            "\\.",
            "\\=",
            "\\#",
            "\\r",
            "\\n",
            "\\t",
            "\\ ",
        ),
    );
    
    /**
     * Stash a reference to the controller on each instantiation
     *
     * @param (class) control: CSSCompression Controller
     */
    public function __construct(CSSCompression_Control $control) {
        $this->Control = $control;
        $this->options =& $control->Option->options;
    }
    
    /**
     * Central trim handler
     *
     * @param (string) css: Stylesheet to trim
     */
    public function trim($css) {
        $css = $this->comments($css);
        $css = $this->escape($css);
        $css = $this->strip($css);
        return $css;
    }
    
    /**
     * Does a quick run through the script to remove all comments from the sheet,
     *
     * @param (string) css: Stylesheet to trim
     */
    private function comments($css) {
        $pos = 0;
        while (preg_match($this->rcmark, $css, $match, PREG_OFFSET_CAPTURE, $pos)) {
            switch ($match[1][0]) {
                // Start of comment block
                case "/*":
                    if (preg_match($this->rendcomment, $css, $m, PREG_OFFSET_CAPTURE, $match[1][1] + 1)) {
                        $end = $m[0][1] - $match[1][1] + strlen($m[0][0]);
                        $css = substr_replace($css, '', $match[1][1], $end);
                        $pos = $match[0][1];
                    }
                    else {
                        $css = substr($css, 0, $match[1][1]);
                        break 2;
                    }
                    break;
                // Start of string
                case "\"":
                    if (preg_match($this->rendquote, $css, $m, PREG_OFFSET_CAPTURE, $match[1][1] + 1)) {
                        $pos = $m[0][1] + strlen($m[0][0]);
                    }
                    else {
                        break 2;
                    }
                    break;
                // Start of string
                case "'":
                    if (preg_match($this->rendsinglequote, $css, $m, PREG_OFFSET_CAPTURE, $match[1][1] + 1)) {
                        $pos = $m[0][1] + strlen($m[0][0]);
                    }
                    else {
                        break 2;
                    }
                    break;
                // Should have never gotten here
                default:
                    break 2;
            }
        }
        return $css;
    }
    
    /**
     * Escape out possible splitter characters within urls
     *
     * @param (string) css: Full stylesheet
     */
    private function escape($css) {
        foreach ($this->rescape as $regex) {
            $start = 0;
            while (preg_match($regex, $css, $match, PREG_OFFSET_CAPTURE, $start)) {
                $value = $match[1][0] . str_replace($this->escaped['search'], $this->escaped['replace'], $match[2][0]) . $match[3][0];
                $css = substr_replace($css, $value, $match[0][1], strlen($match[0][0]));
                $start = $match[0][1] + strlen($value) + 1;
            }
        }
        return $css;
    }
    
    /**
     * Runs initial formatting to setup for compression
     *
     * @param (string) css: CSS Contents
     */
    private function strip($css) {
        // Run replacements
        return trim(preg_replace($this->trimmings['patterns'], $this->trimmings['replacements'], $css));
    }
    
    /**
     * Access to private methods for testing
     *
     * @param (string) method: Method to be called
     * @param (array) args: Array of paramters to be passed in
     */
    public function access($method, $args) {
        if (method_exists($this, $method)) {
            return call_user_func_array(array(
                $this,
                $method,
            ), $args);
        }
        else {
            throw new CSSCompression_Exception("Unknown method in Trim Class - " . $method);
        }
    }

}