1<?php
2
3/*!
4 * cssmin.php v2.4.8-4
5 * Author: Tubal Martin - http://tubalmartin.me/
6 * Repo: https://github.com/tubalmartin/YUI-CSS-compressor-PHP-port
7 *
8 * This is a PHP port of the CSS minification tool distributed with YUICompressor,
9 * itself a port of the cssmin utility by Isaac Schlueter - http://foohack.com/
10 * Permission is hereby granted to use the PHP version under the same
11 * conditions as the YUICompressor.
12 */
13
14/*!
15 * YUI Compressor
16 * http://developer.yahoo.com/yui/compressor/
17 * Author: Julien Lecomte - http://www.julienlecomte.net/
18 * Copyright (c) 2013 Yahoo! Inc. All rights reserved.
19 * The copyrights embodied in the content of this file are licensed
20 * by Yahoo! Inc. under the BSD (revised) open source license.
21 */
22
23class CSSmin
24{
25    const NL = '___YUICSSMIN_PRESERVED_NL___';
26    const TOKEN = '___YUICSSMIN_PRESERVED_TOKEN_';
27    const COMMENT = '___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_';
28    const CLASSCOLON = '___YUICSSMIN_PSEUDOCLASSCOLON___';
29    const QUERY_FRACTION = '___YUICSSMIN_QUERY_FRACTION___';
30
31    private $comments;
32    private $preserved_tokens;
33    private $memory_limit;
34    private $max_execution_time;
35    private $pcre_backtrack_limit;
36    private $pcre_recursion_limit;
37    private $raise_php_limits;
38
39    /**
40     * @param bool|int $raise_php_limits
41     * If true, PHP settings will be raised if needed
42     */
43    public function __construct($raise_php_limits = TRUE)
44    {
45        // Set suggested PHP limits
46        $this->memory_limit = 128 * 1048576; // 128MB in bytes
47        $this->max_execution_time = 60; // 1 min
48        $this->pcre_backtrack_limit = 1000 * 1000;
49        $this->pcre_recursion_limit =  500 * 1000;
50
51        $this->raise_php_limits = (bool) $raise_php_limits;
52    }
53
54    /**
55     * Minify a string of CSS
56     * @param string $css
57     * @param int|bool $linebreak_pos
58     * @return string
59     */
60    public function run($css = '', $linebreak_pos = FALSE)
61    {
62        if (empty($css)) {
63            return '';
64        }
65
66        if ($this->raise_php_limits) {
67            $this->do_raise_php_limits();
68        }
69
70        $this->comments = array();
71        $this->preserved_tokens = array();
72
73        $start_index = 0;
74        $length = strlen($css);
75
76        $css = $this->extract_data_urls($css);
77
78        // collect all comment blocks...
79        while (($start_index = $this->index_of($css, '/*', $start_index)) >= 0) {
80            $end_index = $this->index_of($css, '*/', $start_index + 2);
81            if ($end_index < 0) {
82                $end_index = $length;
83            }
84            $comment_found = $this->str_slice($css, $start_index + 2, $end_index);
85            $this->comments[] = $comment_found;
86            $comment_preserve_string = self::COMMENT . (count($this->comments) - 1) . '___';
87            $css = $this->str_slice($css, 0, $start_index + 2) . $comment_preserve_string . $this->str_slice($css, $end_index);
88            // Set correct start_index: Fixes issue #2528130
89            $start_index = $end_index + 2 + strlen($comment_preserve_string) - strlen($comment_found);
90        }
91
92        // preserve strings so their content doesn't get accidentally minified
93        $css = preg_replace_callback('/(?:"(?:[^\\\\"]|\\\\.|\\\\)*")|'."(?:'(?:[^\\\\']|\\\\.|\\\\)*')/S", array($this, 'replace_string'), $css);
94
95        // Let's divide css code in chunks of 5.000 chars aprox.
96        // Reason: PHP's PCRE functions like preg_replace have a "backtrack limit"
97        // of 100.000 chars by default (php < 5.3.7) so if we're dealing with really
98        // long strings and a (sub)pattern matches a number of chars greater than
99        // the backtrack limit number (i.e. /(.*)/s) PCRE functions may fail silently
100        // returning NULL and $css would be empty.
101        $charset = '';
102        $charset_regexp = '/(@charset)( [^;]+;)/i';
103        $css_chunks = array();
104        $css_chunk_length = 5000; // aprox size, not exact
105        $start_index = 0;
106        $i = $css_chunk_length; // save initial iterations
107        $l = strlen($css);
108
109
110        // if the number of characters is 5000 or less, do not chunk
111        if ($l <= $css_chunk_length) {
112            $css_chunks[] = $css;
113        } else {
114            // chunk css code securely
115            while ($i < $l) {
116                $i += 50; // save iterations
117                if ($l - $start_index <= $css_chunk_length || $i >= $l) {
118                    $css_chunks[] = $this->str_slice($css, $start_index);
119                    break;
120                }
121                if ($css[$i - 1] === '}' && $i - $start_index > $css_chunk_length) {
122                    // If there are two ending curly braces }} separated or not by spaces,
123                    // join them in the same chunk (i.e. @media blocks)
124                    $next_chunk = substr($css, $i);
125                    if (preg_match('/^\s*\}/', $next_chunk)) {
126                        $i = $i + $this->index_of($next_chunk, '}') + 1;
127                    }
128
129                    $css_chunks[] = $this->str_slice($css, $start_index, $i);
130                    $start_index = $i;
131                }
132            }
133        }
134
135        // Minify each chunk
136        for ($i = 0, $n = count($css_chunks); $i < $n; $i++) {
137            $css_chunks[$i] = $this->minify($css_chunks[$i], $linebreak_pos);
138            // Keep the first @charset at-rule found
139            if (empty($charset) && preg_match($charset_regexp, $css_chunks[$i], $matches)) {
140                $charset = strtolower($matches[1]) . $matches[2];
141            }
142            // Delete all @charset at-rules
143            $css_chunks[$i] = preg_replace($charset_regexp, '', $css_chunks[$i]);
144        }
145
146        // Update the first chunk and push the charset to the top of the file.
147        $css_chunks[0] = $charset . $css_chunks[0];
148
149        return implode('', $css_chunks);
150    }
151
152    /**
153     * Sets the memory limit for this script
154     * @param int|string $limit
155     */
156    public function set_memory_limit($limit)
157    {
158        $this->memory_limit = $this->normalize_int($limit);
159    }
160
161    /**
162     * Sets the maximum execution time for this script
163     * @param int|string $seconds
164     */
165    public function set_max_execution_time($seconds)
166    {
167        $this->max_execution_time = (int) $seconds;
168    }
169
170    /**
171     * Sets the PCRE backtrack limit for this script
172     * @param int $limit
173     */
174    public function set_pcre_backtrack_limit($limit)
175    {
176        $this->pcre_backtrack_limit = (int) $limit;
177    }
178
179    /**
180     * Sets the PCRE recursion limit for this script
181     * @param int $limit
182     */
183    public function set_pcre_recursion_limit($limit)
184    {
185        $this->pcre_recursion_limit = (int) $limit;
186    }
187
188    /**
189     * Try to configure PHP to use at least the suggested minimum settings
190     */
191    private function do_raise_php_limits()
192    {
193        $php_limits = array(
194            'memory_limit' => $this->memory_limit,
195            'max_execution_time' => $this->max_execution_time,
196            'pcre.backtrack_limit' => $this->pcre_backtrack_limit,
197            'pcre.recursion_limit' =>  $this->pcre_recursion_limit
198        );
199
200        // If current settings are higher respect them.
201        foreach ($php_limits as $name => $suggested) {
202            $current = $this->normalize_int(ini_get($name));
203            // memory_limit exception: allow -1 for "no memory limit".
204            if ($current > -1 && ($suggested == -1 || $current < $suggested)) {
205                ini_set($name, $suggested);
206            }
207        }
208    }
209
210    /**
211     * Does bulk of the minification
212     * @param string $css
213     * @param int|bool $linebreak_pos
214     * @return string
215     */
216    private function minify($css, $linebreak_pos)
217    {
218        // strings are safe, now wrestle the comments
219        for ($i = 0, $max = count($this->comments); $i < $max; $i++) {
220
221            $token = $this->comments[$i];
222            $placeholder = '/' . self::COMMENT . $i . '___/';
223
224            // ! in the first position of the comment means preserve
225            // so push to the preserved tokens keeping the !
226            if (substr($token, 0, 1) === '!') {
227                $this->preserved_tokens[] = $token;
228                $token_tring = self::TOKEN . (count($this->preserved_tokens) - 1) . '___';
229                $css = preg_replace($placeholder, $token_tring, $css, 1);
230                // Preserve new lines for /*! important comments
231                $css = preg_replace('/\s*[\n\r\f]+\s*(\/\*'. $token_tring .')/S', self::NL.'$1', $css);
232                $css = preg_replace('/('. $token_tring .'\*\/)\s*[\n\r\f]+\s*/', '$1'.self::NL, $css);
233                continue;
234            }
235
236            // \ in the last position looks like hack for Mac/IE5
237            // shorten that to /*\*/ and the next one to /**/
238            if (substr($token, (strlen($token) - 1), 1) === '\\') {
239                $this->preserved_tokens[] = '\\';
240                $css = preg_replace($placeholder,  self::TOKEN . (count($this->preserved_tokens) - 1) . '___', $css, 1);
241                $i = $i + 1; // attn: advancing the loop
242                $this->preserved_tokens[] = '';
243                $css = preg_replace('/' . self::COMMENT . $i . '___/',  self::TOKEN . (count($this->preserved_tokens) - 1) . '___', $css, 1);
244                continue;
245            }
246
247            // keep empty comments after child selectors (IE7 hack)
248            // e.g. html >/**/ body
249            if (strlen($token) === 0) {
250                $start_index = $this->index_of($css, $this->str_slice($placeholder, 1, -1));
251                if ($start_index > 2) {
252                    if (substr($css, $start_index - 3, 1) === '>') {
253                        $this->preserved_tokens[] = '';
254                        $css = preg_replace($placeholder,  self::TOKEN . (count($this->preserved_tokens) - 1) . '___', $css, 1);
255                    }
256                }
257            }
258
259            // in all other cases kill the comment
260            $css = preg_replace('/\/\*' . $this->str_slice($placeholder, 1, -1) . '\*\//', '', $css, 1);
261        }
262
263
264        // Normalize all whitespace strings to single spaces. Easier to work with that way.
265        $css = preg_replace('/\s+/', ' ', $css);
266
267		// Fix IE7 issue on matrix filters which browser accept whitespaces between Matrix parameters
268		$css = preg_replace_callback('/\s*filter\:\s*progid:DXImageTransform\.Microsoft\.Matrix\(([^\)]+)\)/', array($this, 'preserve_old_IE_specific_matrix_definition'), $css);
269
270        // Shorten & preserve calculations calc(...) since spaces are important
271        $css = preg_replace_callback('/calc(\(((?:[^\(\)]+|(?1))*)\))/i', array($this, 'replace_calc'), $css);
272
273        // Replace positive sign from numbers preceded by : or a white-space before the leading space is removed
274        // +1.2em to 1.2em, +.8px to .8px, +2% to 2%
275        $css = preg_replace('/((?<!\\\\)\:|\s)\+(\.?\d+)/S', '$1$2', $css);
276
277        // Remove leading zeros from integer and float numbers preceded by : or a white-space
278        // 000.6 to .6, -0.8 to -.8, 0050 to 50, -01.05 to -1.05
279        $css = preg_replace('/((?<!\\\\)\:|\s)(\-?)0+(\.?\d+)/S', '$1$2$3', $css);
280
281        // Remove trailing zeros from float numbers preceded by : or a white-space
282        // -6.0100em to -6.01em, .0100 to .01, 1.200px to 1.2px
283        $css = preg_replace('/((?<!\\\\)\:|\s)(\-?)(\d?\.\d+?)0+([^\d])/S', '$1$2$3$4', $css);
284
285        // Remove trailing .0 -> -9.0 to -9
286        $css = preg_replace('/((?<!\\\\)\:|\s)(\-?\d+)\.0([^\d])/S', '$1$2$3', $css);
287
288        // Replace 0 length numbers with 0
289        $css = preg_replace('/((?<!\\\\)\:|\s)\-?\.?0+([^\d])/S', '${1}0$2', $css);
290
291        // Remove the spaces before the things that should not have spaces before them.
292        // But, be careful not to turn "p :link {...}" into "p:link{...}"
293        // Swap out any pseudo-class colons with the token, and then swap back.
294        $css = preg_replace_callback('/(?:^|\})[^\{]*\s+\:/', array($this, 'replace_colon'), $css);
295
296        // Remove spaces before the things that should not have spaces before them.
297        $css = preg_replace('/\s+([\!\{\}\;\:\>\+\(\)\]\~\=,])/', '$1', $css);
298
299        // Restore spaces for !important
300        $css = preg_replace('/\!important/i', ' !important', $css);
301
302        // bring back the colon
303        $css = preg_replace('/' . self::CLASSCOLON . '/', ':', $css);
304
305        // retain space for special IE6 cases
306        $css = preg_replace_callback('/\:first\-(line|letter)(\{|,)/i', array($this, 'lowercase_pseudo_first'), $css);
307
308        // no space after the end of a preserved comment
309        $css = preg_replace('/\*\/ /', '*/', $css);
310
311        // lowercase some popular @directives
312        $css = preg_replace_callback('/@(font-face|import|(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?keyframe|media|page|namespace)/i', array($this, 'lowercase_directives'), $css);
313
314        // lowercase some more common pseudo-elements
315        $css = preg_replace_callback('/:(active|after|before|checked|disabled|empty|enabled|first-(?:child|of-type)|focus|hover|last-(?:child|of-type)|link|only-(?:child|of-type)|root|:selection|target|visited)/i', array($this, 'lowercase_pseudo_elements'), $css);
316
317        // lowercase some more common functions
318        $css = preg_replace_callback('/:(lang|not|nth-child|nth-last-child|nth-last-of-type|nth-of-type|(?:-(?:moz|webkit)-)?any)\(/i', array($this, 'lowercase_common_functions'), $css);
319
320        // lower case some common function that can be values
321        // NOTE: rgb() isn't useful as we replace with #hex later, as well as and() is already done for us
322        $css = preg_replace_callback('/([:,\( ]\s*)(attr|color-stop|from|rgba|to|url|(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?(?:calc|max|min|(?:repeating-)?(?:linear|radial)-gradient)|-webkit-gradient)/iS', array($this, 'lowercase_common_functions_values'), $css);
323
324        // Put the space back in some cases, to support stuff like
325        // @media screen and (-webkit-min-device-pixel-ratio:0){
326        $css = preg_replace('/\band\(/i', 'and (', $css);
327
328        // Remove the spaces after the things that should not have spaces after them.
329        $css = preg_replace('/([\!\{\}\:;\>\+\(\[\~\=,])\s+/S', '$1', $css);
330
331        // remove unnecessary semicolons
332        $css = preg_replace('/;+\}/', '}', $css);
333
334        // Fix for issue: #2528146
335        // Restore semicolon if the last property is prefixed with a `*` (lte IE7 hack)
336        // to avoid issues on Symbian S60 3.x browsers.
337        $css = preg_replace('/(\*[a-z0-9\-]+\s*\:[^;\}]+)(\})/', '$1;$2', $css);
338
339        // Replace 0 <length> and 0 <percentage> values with 0.
340        // <length> data type: https://developer.mozilla.org/en-US/docs/Web/CSS/length
341        // <percentage> data type: https://developer.mozilla.org/en-US/docs/Web/CSS/percentage
342        $css = preg_replace('/([^\\\\]\:|\s)0(?:em|ex|ch|rem|vw|vh|vm|vmin|cm|mm|in|px|pt|pc|%)/iS', '${1}0', $css);
343
344		// 0% step in a keyframe? restore the % unit
345		$css = preg_replace_callback('/(@[a-z\-]*?keyframes[^\{]+\{)(.*?)(\}\})/iS', array($this, 'replace_keyframe_zero'), $css);
346
347        // Replace 0 0; or 0 0 0; or 0 0 0 0; with 0.
348        $css = preg_replace('/\:0(?: 0){1,3}(;|\}| \!)/', ':0$1', $css);
349
350        // Fix for issue: #2528142
351        // Replace text-shadow:0; with text-shadow:0 0 0;
352        $css = preg_replace('/(text-shadow\:0)(;|\}| \!)/i', '$1 0 0$2', $css);
353
354        // Replace background-position:0; with background-position:0 0;
355        // same for transform-origin
356        // Changing -webkit-mask-position: 0 0 to just a single 0 will result in the second parameter defaulting to 50% (center)
357        $css = preg_replace('/(background\-position|webkit-mask-position|(?:webkit|moz|o|ms|)\-?transform\-origin)\:0(;|\}| \!)/iS', '$1:0 0$2', $css);
358
359        // Shorten colors from rgb(51,102,153) to #336699, rgb(100%,0%,0%) to #ff0000 (sRGB color space)
360        // Shorten colors from hsl(0, 100%, 50%) to #ff0000 (sRGB color space)
361        // This makes it more likely that it'll get further compressed in the next step.
362        $css = preg_replace_callback('/rgb\s*\(\s*([0-9,\s\-\.\%]+)\s*\)(.{1})/i', array($this, 'rgb_to_hex'), $css);
363        $css = preg_replace_callback('/hsl\s*\(\s*([0-9,\s\-\.\%]+)\s*\)(.{1})/i', array($this, 'hsl_to_hex'), $css);
364
365        // Shorten colors from #AABBCC to #ABC or short color name.
366        $css = $this->compress_hex_colors($css);
367
368        // border: none to border:0, outline: none to outline:0
369        $css = preg_replace('/(border\-?(?:top|right|bottom|left|)|outline)\:none(;|\}| \!)/iS', '$1:0$2', $css);
370
371        // shorter opacity IE filter
372        $css = preg_replace('/progid\:DXImageTransform\.Microsoft\.Alpha\(Opacity\=/i', 'alpha(opacity=', $css);
373
374        // Find a fraction that is used for Opera's -o-device-pixel-ratio query
375        // Add token to add the "\" back in later
376        $css = preg_replace('/\(([a-z\-]+):([0-9]+)\/([0-9]+)\)/i', '($1:$2'. self::QUERY_FRACTION .'$3)', $css);
377
378        // Remove empty rules.
379        $css = preg_replace('/[^\};\{\/]+\{\}/S', '', $css);
380
381        // Add "/" back to fix Opera -o-device-pixel-ratio query
382        $css = preg_replace('/'. self::QUERY_FRACTION .'/', '/', $css);
383
384		// Replace multiple semi-colons in a row by a single one
385        // See SF bug #1980989
386        $css = preg_replace('/;;+/', ';', $css);
387
388        // Restore new lines for /*! important comments
389        $css = preg_replace('/'. self::NL .'/', "\n", $css);
390
391        // Lowercase all uppercase properties
392        $css = preg_replace_callback('/(\{|\;)([A-Z\-]+)(\:)/', array($this, 'lowercase_properties'), $css);
393
394        // Some source control tools don't like it when files containing lines longer
395        // than, say 8000 characters, are checked in. The linebreak option is used in
396        // that case to split long lines after a specific column.
397        if ($linebreak_pos !== FALSE && (int) $linebreak_pos >= 0) {
398            $linebreak_pos = (int) $linebreak_pos;
399            $start_index = $i = 0;
400            while ($i < strlen($css)) {
401                $i++;
402                if ($css[$i - 1] === '}' && $i - $start_index > $linebreak_pos) {
403                    $css = $this->str_slice($css, 0, $i) . "\n" . $this->str_slice($css, $i);
404                    $start_index = $i;
405                }
406            }
407        }
408
409        // restore preserved comments and strings in reverse order
410        for ($i = count($this->preserved_tokens) - 1; $i >= 0; $i--) {
411            $css = preg_replace('/' . self::TOKEN . $i . '___/', $this->preserved_tokens[$i], $css, 1);
412        }
413
414        // Trim the final string (for any leading or trailing white spaces)
415        return trim($css);
416    }
417
418    /**
419     * Utility method to replace all data urls with tokens before we start
420     * compressing, to avoid performance issues running some of the subsequent
421     * regexes against large strings chunks.
422     *
423     * @param string $css
424     * @return string
425     */
426    private function extract_data_urls($css)
427    {
428        // Leave data urls alone to increase parse performance.
429        $max_index = strlen($css) - 1;
430        $append_index = $index = $last_index = $offset = 0;
431        $sb = array();
432        $pattern = '/url\(\s*(["\']?)data\:/i';
433
434        // Since we need to account for non-base64 data urls, we need to handle
435        // ' and ) being part of the data string. Hence switching to indexOf,
436        // to determine whether or not we have matching string terminators and
437        // handling sb appends directly, instead of using matcher.append* methods.
438
439        while (preg_match($pattern, $css, $m, 0, $offset)) {
440            $index = $this->index_of($css, $m[0], $offset);
441            $last_index = $index + strlen($m[0]);
442            $start_index = $index + 4; // "url(".length()
443            $end_index = $last_index - 1;
444            $terminator = $m[1]; // ', " or empty (not quoted)
445            $found_terminator = FALSE;
446
447            if (strlen($terminator) === 0) {
448                $terminator = ')';
449            }
450
451            while ($found_terminator === FALSE && $end_index+1 <= $max_index) {
452                $end_index = $this->index_of($css, $terminator, $end_index + 1);
453
454                // endIndex == 0 doesn't really apply here
455                if ($end_index > 0 && substr($css, $end_index - 1, 1) !== '\\') {
456                    $found_terminator = TRUE;
457                    if (')' != $terminator) {
458                        $end_index = $this->index_of($css, ')', $end_index);
459                    }
460                }
461            }
462
463            // Enough searching, start moving stuff over to the buffer
464            $sb[] = $this->str_slice($css, $append_index, $index);
465
466            if ($found_terminator) {
467                $token = $this->str_slice($css, $start_index, $end_index);
468                $token = preg_replace('/\s+/', '', $token);
469                $this->preserved_tokens[] = $token;
470
471                $preserver = 'url(' . self::TOKEN . (count($this->preserved_tokens) - 1) . '___)';
472                $sb[] = $preserver;
473
474                $append_index = $end_index + 1;
475            } else {
476                // No end terminator found, re-add the whole match. Should we throw/warn here?
477                $sb[] = $this->str_slice($css, $index, $last_index);
478                $append_index = $last_index;
479            }
480
481            $offset = $last_index;
482        }
483
484        $sb[] = $this->str_slice($css, $append_index);
485
486        return implode('', $sb);
487    }
488
489    /**
490     * Utility method to compress hex color values of the form #AABBCC to #ABC or short color name.
491     *
492     * DOES NOT compress CSS ID selectors which match the above pattern (which would break things).
493     * e.g. #AddressForm { ... }
494     *
495     * DOES NOT compress IE filters, which have hex color values (which would break things).
496     * e.g. filter: chroma(color="#FFFFFF");
497     *
498     * DOES NOT compress invalid hex values.
499     * e.g. background-color: #aabbccdd
500     *
501     * @param string $css
502     * @return string
503     */
504    private function compress_hex_colors($css)
505    {
506        // Look for hex colors inside { ... } (to avoid IDs) and which don't have a =, or a " in front of them (to avoid filters)
507        $pattern = '/(\=\s*?["\']?)?#([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])(\}|[^0-9a-f{][^{]*?\})/iS';
508        $_index = $index = $last_index = $offset = 0;
509        $sb = array();
510        // See: http://ajaxmin.codeplex.com/wikipage?title=CSS%20Colors
511        $short_safe = array(
512            '#808080' => 'gray',
513            '#008000' => 'green',
514            '#800000' => 'maroon',
515            '#000080' => 'navy',
516            '#808000' => 'olive',
517            '#ffa500' => 'orange',
518            '#800080' => 'purple',
519            '#c0c0c0' => 'silver',
520            '#008080' => 'teal',
521            '#f00' => 'red'
522        );
523
524        while (preg_match($pattern, $css, $m, 0, $offset)) {
525            $index = $this->index_of($css, $m[0], $offset);
526            $last_index = $index + strlen($m[0]);
527            $is_filter = $m[1] !== null && $m[1] !== '';
528
529            $sb[] = $this->str_slice($css, $_index, $index);
530
531            if ($is_filter) {
532                // Restore, maintain case, otherwise filter will break
533                $sb[] = $m[1] . '#' . $m[2] . $m[3] . $m[4] . $m[5] . $m[6] . $m[7];
534            } else {
535                if (strtolower($m[2]) == strtolower($m[3]) &&
536                    strtolower($m[4]) == strtolower($m[5]) &&
537                    strtolower($m[6]) == strtolower($m[7])) {
538                    // Compress.
539                    $hex = '#' . strtolower($m[3] . $m[5] . $m[7]);
540                } else {
541                    // Non compressible color, restore but lower case.
542                    $hex = '#' . strtolower($m[2] . $m[3] . $m[4] . $m[5] . $m[6] . $m[7]);
543                }
544                // replace Hex colors to short safe color names
545                $sb[] = array_key_exists($hex, $short_safe) ? $short_safe[$hex] : $hex;
546            }
547
548            $_index = $offset = $last_index - strlen($m[8]);
549        }
550
551        $sb[] = $this->str_slice($css, $_index);
552
553        return implode('', $sb);
554    }
555
556    /* CALLBACKS
557     * ---------------------------------------------------------------------------------------------
558     */
559
560    private function replace_string($matches)
561    {
562        $match = $matches[0];
563        $quote = substr($match, 0, 1);
564        // Must use addcslashes in PHP to avoid parsing of backslashes
565        $match = addcslashes($this->str_slice($match, 1, -1), '\\');
566
567        // maybe the string contains a comment-like substring?
568        // one, maybe more? put'em back then
569        if (($pos = $this->index_of($match, self::COMMENT)) >= 0) {
570            for ($i = 0, $max = count($this->comments); $i < $max; $i++) {
571                $match = preg_replace('/' . self::COMMENT . $i . '___/', $this->comments[$i], $match, 1);
572            }
573        }
574
575        // minify alpha opacity in filter strings
576        $match = preg_replace('/progid\:DXImageTransform\.Microsoft\.Alpha\(Opacity\=/i', 'alpha(opacity=', $match);
577
578        $this->preserved_tokens[] = $match;
579        return $quote . self::TOKEN . (count($this->preserved_tokens) - 1) . '___' . $quote;
580    }
581
582    private function replace_colon($matches)
583    {
584        return preg_replace('/\:/', self::CLASSCOLON, $matches[0]);
585    }
586
587    private function replace_calc($matches)
588    {
589        $this->preserved_tokens[] = trim(preg_replace('/\s*([\*\/\(\),])\s*/', '$1', $matches[2]));
590        return 'calc('. self::TOKEN . (count($this->preserved_tokens) - 1) . '___' . ')';
591    }
592
593	private function preserve_old_IE_specific_matrix_definition($matches)
594	{
595		$this->preserved_tokens[] = $matches[1];
596		return 'filter:progid:DXImageTransform.Microsoft.Matrix(' . self::TOKEN . (count($this->preserved_tokens) - 1) . '___' . ')';
597    }
598
599	private function replace_keyframe_zero($matches)
600    {
601        return $matches[1] . preg_replace('/0(\{|,[^\)\{]+\{)/', '0%$1', $matches[2]) . $matches[3];
602    }
603
604    private function rgb_to_hex($matches)
605    {
606        // Support for percentage values rgb(100%, 0%, 45%);
607        if ($this->index_of($matches[1], '%') >= 0){
608            $rgbcolors = explode(',', str_replace('%', '', $matches[1]));
609            for ($i = 0; $i < count($rgbcolors); $i++) {
610                $rgbcolors[$i] = $this->round_number(floatval($rgbcolors[$i]) * 2.55);
611            }
612        } else {
613            $rgbcolors = explode(',', $matches[1]);
614        }
615
616        // Values outside the sRGB color space should be clipped (0-255)
617        for ($i = 0; $i < count($rgbcolors); $i++) {
618            $rgbcolors[$i] = $this->clamp_number(intval($rgbcolors[$i], 10), 0, 255);
619            $rgbcolors[$i] = sprintf("%02x", $rgbcolors[$i]);
620        }
621
622        // Fix for issue #2528093
623        if (!preg_match('/[\s\,\);\}]/', $matches[2])){
624            $matches[2] = ' ' . $matches[2];
625        }
626
627        return '#' . implode('', $rgbcolors) . $matches[2];
628    }
629
630    private function hsl_to_hex($matches)
631    {
632        $values = explode(',', str_replace('%', '', $matches[1]));
633        $h = floatval($values[0]);
634        $s = floatval($values[1]);
635        $l = floatval($values[2]);
636
637        // Wrap and clamp, then fraction!
638        $h = ((($h % 360) + 360) % 360) / 360;
639        $s = $this->clamp_number($s, 0, 100) / 100;
640        $l = $this->clamp_number($l, 0, 100) / 100;
641
642        if ($s == 0) {
643            $r = $g = $b = $this->round_number(255 * $l);
644        } else {
645            $v2 = $l < 0.5 ? $l * (1 + $s) : ($l + $s) - ($s * $l);
646            $v1 = (2 * $l) - $v2;
647            $r = $this->round_number(255 * $this->hue_to_rgb($v1, $v2, $h + (1/3)));
648            $g = $this->round_number(255 * $this->hue_to_rgb($v1, $v2, $h));
649            $b = $this->round_number(255 * $this->hue_to_rgb($v1, $v2, $h - (1/3)));
650        }
651
652        return $this->rgb_to_hex(array('', $r.','.$g.','.$b, $matches[2]));
653    }
654
655    private function lowercase_pseudo_first($matches)
656    {
657        return ':first-'. strtolower($matches[1]) .' '. $matches[2];
658    }
659
660    private function lowercase_directives($matches)
661    {
662        return '@'. strtolower($matches[1]);
663    }
664
665    private function lowercase_pseudo_elements($matches)
666    {
667        return ':'. strtolower($matches[1]);
668    }
669
670    private function lowercase_common_functions($matches)
671    {
672        return ':'. strtolower($matches[1]) .'(';
673    }
674
675    private function lowercase_common_functions_values($matches)
676    {
677        return $matches[1] . strtolower($matches[2]);
678    }
679
680    private function lowercase_properties($matches)
681    {
682        return $matches[1].strtolower($matches[2]).$matches[3];
683    }
684
685    /* HELPERS
686     * ---------------------------------------------------------------------------------------------
687     */
688
689    private function hue_to_rgb($v1, $v2, $vh)
690    {
691        $vh = $vh < 0 ? $vh + 1 : ($vh > 1 ? $vh - 1 : $vh);
692        if ($vh * 6 < 1) return $v1 + ($v2 - $v1) * 6 * $vh;
693        if ($vh * 2 < 1) return $v2;
694        if ($vh * 3 < 2) return $v1 + ($v2 - $v1) * ((2/3) - $vh) * 6;
695        return $v1;
696    }
697
698    private function round_number($n)
699    {
700        return intval(floor(floatval($n) + 0.5), 10);
701    }
702
703    private function clamp_number($n, $min, $max)
704    {
705        return min(max($n, $min), $max);
706    }
707
708    /**
709     * PHP port of Javascript's "indexOf" function for strings only
710     * Author: Tubal Martin http://blog.margenn.com
711     *
712     * @param string $haystack
713     * @param string $needle
714     * @param int    $offset index (optional)
715     * @return int
716     */
717    private function index_of($haystack, $needle, $offset = 0)
718    {
719        $index = strpos($haystack, $needle, $offset);
720
721        return ($index !== FALSE) ? $index : -1;
722    }
723
724    /**
725     * PHP port of Javascript's "slice" function for strings only
726     * Author: Tubal Martin http://blog.margenn.com
727     * Tests: http://margenn.com/tubal/str_slice/
728     *
729     * @param string   $str
730     * @param int      $start index
731     * @param int|bool $end index (optional)
732     * @return string
733     */
734    private function str_slice($str, $start = 0, $end = FALSE)
735    {
736        if ($end !== FALSE && ($start < 0 || $end <= 0)) {
737            $max = strlen($str);
738
739            if ($start < 0) {
740                if (($start = $max + $start) < 0) {
741                    return '';
742                }
743            }
744
745            if ($end < 0) {
746                if (($end = $max + $end) < 0) {
747                    return '';
748                }
749            }
750
751            if ($end <= $start) {
752                return '';
753            }
754        }
755
756        $slice = ($end === FALSE) ? substr($str, $start) : substr($str, $start, $end - $start);
757        return ($slice === FALSE) ? '' : $slice;
758    }
759
760    /**
761     * Convert strings like "64M" or "30" to int values
762     * @param mixed $size
763     * @return int
764     */
765    private function normalize_int($size)
766    {
767        if (is_string($size)) {
768            switch (substr($size, -1)) {
769                case 'M': case 'm': return (int) $size * 1048576;
770                case 'K': case 'k': return (int) $size * 1024;
771                case 'G': case 'g': return (int) $size * 1073741824;
772            }
773        }
774
775        return (int) $size;
776    }
777}
778