CSSMin.inc in Advanced CSS/JS Aggregation 7.2

File

advagg_css_compress/yui/CSSMin.inc

<?php

// @codingStandardsIgnoreFile
// @ignore comment_docblock_file:file
// @ignore style_curly_braces:file
// @ignore style_string_spacing:file
// @ignore style_else_spacing:file
// @ignore comment_comment_docblock_missing:file
// @ignore comment_comment_eg:file
// @ignore production_code:file
// @ignore druplart_unary:file
// @ignore style_uppercase_constants:file
// @ignore comment_comment_space:file
// @ignore druplart_conditional_assignment:file
// @ignore style_paren_spacing:file
// @ignore :file

/*!
 * cssmin.php
 * Author: Tubal Martin - http://tubalmartin.me/
 * Repo: https://github.com/tubalmartin/YUI-CSS-compressor-PHP-port
 *
 * This is a PHP port of the CSS minification tool distributed with YUICompressor,
 * itself a port of the cssmin utility by Isaac Schlueter - http://foohack.com/
 * Permission is hereby granted to use the PHP version under the same
 * conditions as the YUICompressor.
 */

/*!
 * YUI Compressor
 * http://developer.yahoo.com/yui/compressor/
 * Author: Julien Lecomte - http://www.julienlecomte.net/
 * Copyright (c) 2013 Yahoo! Inc. All rights reserved.
 * The copyrights embodied in the content of this file are licensed
 * by Yahoo! Inc. under the BSD (revised) open source license.
 */
class CSSmin {
  const NL = '___YUICSSMIN_PRESERVED_NL___';
  const CLASSCOLON = '___YUICSSMIN_PSEUDOCLASSCOLON___';
  const QUERY_FRACTION = '___YUICSSMIN_QUERY_FRACTION___';
  const TOKEN = '___YUICSSMIN_PRESERVED_TOKEN_';
  const COMMENT = '___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_';
  const AT_RULE_BLOCK = '___YUICSSMIN_PRESERVE_AT_RULE_BLOCK_';
  private $comments;
  private $atRuleBlocks;
  private $preservedTokens;
  private $chunkLength = 5000;
  private $minChunkLength = 100;
  private $memoryLimit;
  private $maxExecutionTime = 60;

  // 1 min
  private $pcreBacktrackLimit;
  private $pcreRecursionLimit;
  private $raisePhpLimits;
  private $unitsGroupRegex = '(?:ch|cm|em|ex|gd|in|mm|px|pt|pc|q|rem|vh|vmax|vmin|vw|%)';
  private $numRegex;

  /**
   * @param bool|int $raisePhpLimits If true, PHP settings will be raised if needed
   */
  public function __construct($raisePhpLimits = true) {
    $this->memoryLimit = 128 * 1048576;

    // 128MB in bytes
    $this->pcreBacktrackLimit = 1000 * 1000;
    $this->pcreRecursionLimit = 500 * 1000;
    $this->raisePhpLimits = (bool) $raisePhpLimits;
    $this->numRegex = '(?:\\+|-)?\\d*\\.?\\d+' . $this->unitsGroupRegex . '?';
  }

  /**
   * Minifies a string of CSS
   * @param string $css
   * @param int|bool $linebreakPos
   * @return string
   */
  public function run($css = '', $linebreakPos = false) {
    if (empty($css)) {
      return '';
    }
    if ($this->raisePhpLimits) {
      $this
        ->doRaisePhpLimits();
    }
    $this->comments = array();
    $this->atRuleBlocks = array();
    $this->preservedTokens = array();

    // process data urls
    $css = $this
      ->processDataUrls($css);

    // process comments
    $css = preg_replace_callback('/(?<!\\\\)\\/\\*(.*?)\\*(?<!\\\\)\\//Ss', array(
      $this,
      'processComments',
    ), $css);

    // process strings so their content doesn't get accidentally minified
    $css = preg_replace_callback('/(?:"(?:[^\\\\"]|\\\\.|\\\\)*")|' . "(?:'(?:[^\\\\']|\\\\.|\\\\)*')/S", array(
      $this,
      'processStrings',
    ), $css);

    // Safe chunking: process at rule blocks so after chunking nothing gets stripped out
    $css = preg_replace_callback('/@(?:document|(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?keyframes|media|supports).+?\\}\\s*\\}/si', array(
      $this,
      'processAtRuleBlocks',
    ), $css);

    // Let's divide css code in chunks of {$this->chunkLength} chars aprox.
    // Reason: PHP's PCRE functions like preg_replace have a "backtrack limit"
    // of 100.000 chars by default (php < 5.3.7) so if we're dealing with really
    // long strings and a (sub)pattern matches a number of chars greater than
    // the backtrack limit number (i.e. /(.*)/s) PCRE functions may fail silently
    // returning NULL and $css would be empty.
    $charset = '';
    $charsetRegexp = '/(@charset)( [^;]+;)/i';
    $cssChunks = array();
    $l = strlen($css);

    // if the number of characters is <= {$this->chunkLength}, do not chunk
    if ($l <= $this->chunkLength) {
      $cssChunks[] = $css;
    }
    else {

      // chunk css code securely
      for ($startIndex = 0, $i = $this->chunkLength; $i < $l; $i++) {
        if ($css[$i - 1] === '}' && $i - $startIndex >= $this->chunkLength) {
          $cssChunks[] = $this
            ->strSlice($css, $startIndex, $i);
          $startIndex = $i;

          // Move forward saving iterations when possible!
          if ($startIndex + $this->chunkLength < $l) {
            $i += $this->chunkLength;
          }
        }
      }

      // Final chunk
      $cssChunks[] = $this
        ->strSlice($css, $startIndex);
    }

    // Minify each chunk
    for ($i = 0, $n = count($cssChunks); $i < $n; $i++) {
      $cssChunks[$i] = $this
        ->minify($cssChunks[$i], $linebreakPos);

      // Keep the first @charset at-rule found
      if (empty($charset) && preg_match($charsetRegexp, $cssChunks[$i], $matches)) {
        $charset = strtolower($matches[1]) . $matches[2];
      }

      // Delete all @charset at-rules
      $cssChunks[$i] = preg_replace($charsetRegexp, '', $cssChunks[$i]);
    }

    // Update the first chunk and push the charset to the top of the file.
    $cssChunks[0] = $charset . $cssChunks[0];
    return trim(implode('', $cssChunks));
  }

  /**
   * Sets the approximate number of characters to use when splitting a string in chunks.
   * @param int $length
   */
  public function set_chunk_length($length) {
    $length = (int) $length;
    $this->chunkLength = $length < $this->minChunkLength ? $this->minChunkLength : $length;
  }

  /**
   * Sets the memory limit for this script
   * @param int|string $limit
   */
  public function set_memory_limit($limit) {
    $this->memoryLimit = $this
      ->normalizeInt($limit);
  }

  /**
   * Sets the maximum execution time for this script
   * @param int|string $seconds
   */
  public function set_max_execution_time($seconds) {
    $this->maxExecutionTime = (int) $seconds;
  }

  /**
   * Sets the PCRE backtrack limit for this script
   * @param int $limit
   */
  public function set_pcre_backtrack_limit($limit) {
    $this->pcreBacktrackLimit = (int) $limit;
  }

  /**
   * Sets the PCRE recursion limit for this script
   * @param int $limit
   */
  public function set_pcre_recursion_limit($limit) {
    $this->pcreRecursionLimit = (int) $limit;
  }

  /**
   * Tries to configure PHP to use at least the suggested minimum settings
   * @return void
   */
  private function doRaisePhpLimits() {
    $phpLimits = array(
      'memory_limit' => $this->memoryLimit,
      'max_execution_time' => $this->maxExecutionTime,
      'pcre.backtrack_limit' => $this->pcreBacktrackLimit,
      'pcre.recursion_limit' => $this->pcreRecursionLimit,
    );

    // If current settings are higher respect them.
    foreach ($phpLimits as $name => $suggested) {
      $current = $this
        ->normalizeInt(ini_get($name));
      if ($current > $suggested) {
        continue;
      }

      // memoryLimit exception: allow -1 for "no memory limit".
      if ($name === 'memory_limit' && $current === -1) {
        continue;
      }

      // maxExecutionTime exception: allow 0 for "no memory limit".
      if ($name === 'max_execution_time' && $current === 0) {
        continue;
      }
      ini_set($name, $suggested);
    }
  }

  /**
   * Registers a preserved token
   * @param $token
   * @return string The token ID string
   */
  private function registerPreservedToken($token) {
    $this->preservedTokens[] = $token;
    return self::TOKEN . (count($this->preservedTokens) - 1) . '___';
  }

  /**
   * Gets the regular expression to match the specified token ID string
   * @param $id
   * @return string
   */
  private function getPreservedTokenPlaceholderRegexById($id) {
    return '/' . self::TOKEN . $id . '___/';
  }

  /**
   * Registers a candidate comment token
   * @param $comment
   * @return string The comment token ID string
   */
  private function registerComment($comment) {
    $this->comments[] = $comment;
    return '/*' . self::COMMENT . (count($this->comments) - 1) . '___*/';
  }

  /**
   * Gets the candidate comment token ID string for the specified comment token ID
   * @param $id
   * @return string
   */
  private function getCommentPlaceholderById($id) {
    return self::COMMENT . $id . '___';
  }

  /**
   * Gets the regular expression to match the specified comment token ID string
   * @param $id
   * @return string
   */
  private function getCommentPlaceholderRegexById($id) {
    return '/' . $this
      ->getCommentPlaceholderById($id) . '/';
  }

  /**
   * Registers an at rule block token
   * @param $block
   * @return string The comment token ID string
   */
  private function registerAtRuleBlock($block) {
    $this->atRuleBlocks[] = $block;
    return self::AT_RULE_BLOCK . (count($this->atRuleBlocks) - 1) . '___';
  }

  /**
   * Gets the regular expression to match the specified at rule block token ID string
   * @param $id
   * @return string
   */
  private function getAtRuleBlockPlaceholderRegexById($id) {
    return '/' . self::AT_RULE_BLOCK . $id . '___/';
  }

  /**
   * Minifies the given input CSS string
   * @param string $css
   * @param int|bool $linebreakPos
   * @return string
   */
  private function minify($css, $linebreakPos) {

    // Restore preserved at rule blocks
    for ($i = 0, $max = count($this->atRuleBlocks); $i < $max; $i++) {
      $css = preg_replace($this
        ->getAtRuleBlockPlaceholderRegexById($i), $this
        ->escapeReplacementString($this->atRuleBlocks[$i]), $css, 1);
    }

    // strings are safe, now wrestle the comments
    for ($i = 0, $max = count($this->comments); $i < $max; $i++) {
      $comment = $this->comments[$i];
      $commentPlaceholder = $this
        ->getCommentPlaceholderById($i);
      $commentPlaceholderRegex = $this
        ->getCommentPlaceholderRegexById($i);

      // ! in the first position of the comment means preserve
      // so push to the preserved tokens keeping the !
      if (preg_match('/^!/', $comment)) {
        $preservedTokenPlaceholder = $this
          ->registerPreservedToken($comment);
        $css = preg_replace($commentPlaceholderRegex, $preservedTokenPlaceholder, $css, 1);

        // Preserve new lines for /*! important comments
        $css = preg_replace('/\\R+\\s*(\\/\\*' . $preservedTokenPlaceholder . ')/', self::NL . '$1', $css);
        $css = preg_replace('/(' . $preservedTokenPlaceholder . '\\*\\/)\\s*\\R+/', '$1' . self::NL, $css);
        continue;
      }

      // \ in the last position looks like hack for Mac/IE5
      // shorten that to /*\*/ and the next one to /**/
      if (preg_match('/\\\\$/', $comment)) {
        $preservedTokenPlaceholder = $this
          ->registerPreservedToken('\\');
        $css = preg_replace($commentPlaceholderRegex, $preservedTokenPlaceholder, $css, 1);
        $i = $i + 1;

        // attn: advancing the loop
        $preservedTokenPlaceholder = $this
          ->registerPreservedToken('');
        $css = preg_replace($this
          ->getCommentPlaceholderRegexById($i), $preservedTokenPlaceholder, $css, 1);
        continue;
      }

      // keep empty comments after child selectors (IE7 hack)
      // e.g. html >/**/ body
      if (strlen($comment) === 0) {
        $startIndex = $this
          ->indexOf($css, $commentPlaceholder);
        if ($startIndex > 2) {
          if (substr($css, $startIndex - 3, 1) === '>') {
            $preservedTokenPlaceholder = $this
              ->registerPreservedToken('');
            $css = preg_replace($commentPlaceholderRegex, $preservedTokenPlaceholder, $css, 1);
            continue;
          }
        }
      }

      // in all other cases kill the comment
      $css = preg_replace('/\\/\\*' . $commentPlaceholder . '\\*\\//', '', $css, 1);
    }

    // Normalize all whitespace strings to single spaces. Easier to work with that way.
    $css = preg_replace('/\\s+/', ' ', $css);

    // Remove spaces before & after newlines
    $css = preg_replace('/\\s*' . self::NL . '\\s*/', self::NL, $css);

    // Fix IE7 issue on matrix filters which browser accept whitespaces between Matrix parameters
    $css = preg_replace_callback('/\\s*filter:\\s*progid:DXImageTransform\\.Microsoft\\.Matrix\\(([^)]+)\\)/', array(
      $this,
      'processOldIeSpecificMatrixDefinition',
    ), $css);

    // Shorten & preserve calculations calc(...) since spaces are important
    $css = preg_replace_callback('/calc(\\(((?:[^()]+|(?1))*)\\))/i', array(
      $this,
      'processCalc',
    ), $css);

    // Replace positive sign from numbers preceded by : or a white-space before the leading space is removed
    // +1.2em to 1.2em, +.8px to .8px, +2% to 2%
    $css = preg_replace('/((?<!\\\\):|\\s)\\+(\\.?\\d+)/S', '$1$2', $css);

    // Remove leading zeros from integer and float numbers preceded by : or a white-space
    // 000.6 to .6, -0.8 to -.8, 0050 to 50, -01.05 to -1.05
    $css = preg_replace('/((?<!\\\\):|\\s)(-?)0+(\\.?\\d+)/S', '$1$2$3', $css);

    // Remove trailing zeros from float numbers preceded by : or a white-space
    // -6.0100em to -6.01em, .0100 to .01, 1.200px to 1.2px
    $css = preg_replace('/((?<!\\\\):|\\s)(-?)(\\d?\\.\\d+?)0+([^\\d])/S', '$1$2$3$4', $css);

    // Remove trailing .0 -> -9.0 to -9
    $css = preg_replace('/((?<!\\\\):|\\s)(-?\\d+)\\.0([^\\d])/S', '$1$2$3', $css);

    // Replace 0 length numbers with 0
    $css = preg_replace('/((?<!\\\\):|\\s)-?\\.?0+([^\\d])/S', '${1}0$2', $css);

    // Remove the spaces before the things that should not have spaces before them.
    // But, be careful not to turn "p :link {...}" into "p:link{...}"
    // Swap out any pseudo-class colons with the token, and then swap back.
    $css = preg_replace_callback('/(?:^|\\})[^{]*\\s+:/', array(
      $this,
      'processColon',
    ), $css);

    // Remove spaces before the things that should not have spaces before them.
    $css = preg_replace('/\\s+([!{};:>+()\\]~=,])/', '$1', $css);

    // Restore spaces for !important
    $css = preg_replace('/!important/i', ' !important', $css);

    // bring back the colon
    $css = preg_replace('/' . self::CLASSCOLON . '/', ':', $css);

    // retain space for special IE6 cases
    $css = preg_replace_callback('/:first-(line|letter)(\\{|,)/i', array(
      $this,
      'lowercasePseudoFirst',
    ), $css);

    // no space after the end of a preserved comment
    $css = preg_replace('/\\*\\/ /', '*/', $css);

    // lowercase some popular @directives
    $css = preg_replace_callback('/@(document|font-face|import|(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?keyframes|media|namespace|page|' . 'supports|viewport)/i', array(
      $this,
      'lowercaseDirectives',
    ), $css);

    // lowercase some more common pseudo-elements
    $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,
      'lowercasePseudoElements',
    ), $css);

    // lowercase some more common functions
    $css = preg_replace_callback('/:(lang|not|nth-child|nth-last-child|nth-last-of-type|nth-of-type|(?:-(?:moz|webkit)-)?any)\\(/i', array(
      $this,
      'lowercaseCommonFunctions',
    ), $css);

    // lower case some common function that can be values
    // NOTE: rgb() isn't useful as we replace with #hex later, as well as and() is already done for us
    $css = preg_replace_callback('/([:,( ]\\s*)(attr|color-stop|from|rgba|to|url|-webkit-gradient|' . '(?:-(?:atsc|khtml|moz|ms|o|wap|webkit)-)?(?:calc|max|min|(?:repeating-)?(?:linear|radial)-gradient))/iS', array(
      $this,
      'lowercaseCommonFunctionsValues',
    ), $css);

    // Put the space back in some cases, to support stuff like
    // @media screen and (-webkit-min-device-pixel-ratio:0){
    $css = preg_replace_callback('/(\\s|\\)\\s)(and|not|or)\\(/i', array(
      $this,
      'processAtRulesOperators',
    ), $css);

    // Remove the spaces after the things that should not have spaces after them.
    $css = preg_replace('/([!{}:;>+(\\[~=,])\\s+/S', '$1', $css);

    // remove unnecessary semicolons
    $css = preg_replace('/;+\\}/', '}', $css);

    // Fix for issue: #2528146
    // Restore semicolon if the last property is prefixed with a `*` (lte IE7 hack)
    // to avoid issues on Symbian S60 3.x browsers.
    $css = preg_replace('/(\\*[a-z0-9\\-]+\\s*:[^;}]+)(\\})/', '$1;$2', $css);

    // Shorten zero values for safe properties only
    $css = $this
      ->shortenZeroValues($css);

    // Shorten font-weight values
    $css = preg_replace('/(font-weight:)bold\\b/i', '${1}700', $css);
    $css = preg_replace('/(font-weight:)normal\\b/i', '${1}400', $css);

    // Shorten suitable shorthand properties with repeated non-zero values
    $css = preg_replace('/(margin|padding):(' . $this->numRegex . ') (' . $this->numRegex . ') (?:\\2) (?:\\3)(;|\\}| !)/i', '$1:$2 $3$4', $css);
    $css = preg_replace('/(margin|padding):(' . $this->numRegex . ') (' . $this->numRegex . ') (' . $this->numRegex . ') (?:\\3)(;|\\}| !)/i', '$1:$2 $3 $4$5', $css);

    // Shorten colors from rgb(51,102,153) to #336699, rgb(100%,0%,0%) to #ff0000 (sRGB color space)
    // Shorten colors from hsl(0, 100%, 50%) to #ff0000 (sRGB color space)
    // This makes it more likely that it'll get further compressed in the next step.
    $css = preg_replace_callback('/rgb\\s*\\(\\s*([0-9,\\s\\-.%]+)\\s*\\)(.{1})/i', array(
      $this,
      'rgbToHex',
    ), $css);
    $css = preg_replace_callback('/hsl\\s*\\(\\s*([0-9,\\s\\-.%]+)\\s*\\)(.{1})/i', array(
      $this,
      'hslToHex',
    ), $css);

    // Shorten colors from #AABBCC to #ABC or shorter color name.
    $css = $this
      ->shortenHexColors($css);

    // Shorten long named colors: white -> #fff.
    $css = $this
      ->shortenNamedColors($css);

    // shorter opacity IE filter
    $css = preg_replace('/progid:DXImageTransform\\.Microsoft\\.Alpha\\(Opacity=/i', 'alpha(opacity=', $css);

    // Find a fraction that is used for Opera's -o-device-pixel-ratio query
    // Add token to add the "\" back in later
    $css = preg_replace('/\\(([a-z\\-]+):([0-9]+)\\/([0-9]+)\\)/i', '($1:$2' . self::QUERY_FRACTION . '$3)', $css);

    // Patch new lines to avoid being removed when followed by empty rules cases
    $css = preg_replace('/' . self::NL . '/', self::NL . '}', $css);

    // Remove empty rules.
    $css = preg_replace('/[^{};\\/]+\\{\\}/S', '', $css);

    // Restore new lines for /*! important comments
    $css = preg_replace('/' . self::NL . '}/', "\n", $css);

    // Add "/" back to fix Opera -o-device-pixel-ratio query
    $css = preg_replace('/' . self::QUERY_FRACTION . '/', '/', $css);

    // Replace multiple semi-colons in a row by a single one
    // See SF bug #1980989
    $css = preg_replace('/;;+/', ';', $css);

    // Lowercase all uppercase properties
    $css = preg_replace_callback('/(\\{|;)([A-Z\\-]+)(:)/', array(
      $this,
      'lowercaseProperties',
    ), $css);

    // Some source control tools don't like it when files containing lines longer
    // than, say 8000 characters, are checked in. The linebreak option is used in
    // that case to split long lines after a specific column.
    if ($linebreakPos !== false && (int) $linebreakPos >= 0) {
      $linebreakPos = (int) $linebreakPos;
      for ($startIndex = $i = 1, $l = strlen($css); $i < $l; $i++) {
        if ($css[$i - 1] === '}' && $i - $startIndex > $linebreakPos) {
          $css = $this
            ->strSlice($css, 0, $i) . "\n" . $this
            ->strSlice($css, $i);
          $l = strlen($css);
          $startIndex = $i;
        }
      }
    }

    // restore preserved comments and strings in reverse order
    for ($i = count($this->preservedTokens) - 1; $i >= 0; $i--) {
      $css = preg_replace($this
        ->getPreservedTokenPlaceholderRegexById($i), $this
        ->escapeReplacementString($this->preservedTokens[$i]), $css, 1);
    }

    // Trim the final string for any leading or trailing white space but respect newlines!
    $css = preg_replace('/(^ | $)/', '', $css);
    return $css;
  }

  /**
   * 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.
   * @param string $css
   * @return string
   */
  private function processDataUrls($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);
  }

  /**
   * Shortens all zero values for a set of safe properties
   * e.g. padding: 0px 1px; -> padding:0 1px
   * e.g. padding: 0px 0rem 0em 0.0pc; -> padding:0
   * @param string $css
   * @return string
   */
  private function shortenZeroValues($css) {
    $unitsGroupReg = $this->unitsGroupRegex;
    $numOrPosReg = '(' . $this->numRegex . '|top|left|bottom|right|center)';
    $oneZeroSafeProperties = array(
      '(?:line-)?height',
      '(?:(?:min|max)-)?width',
      'top',
      'left',
      'background-position',
      'bottom',
      'right',
      'border(?:-(?:top|left|bottom|right))?(?:-width)?',
      'border-(?:(?:top|bottom)-(?:left|right)-)?radius',
      'column-(?:gap|width)',
      'margin(?:-(?:top|left|bottom|right))?',
      'outline-width',
      'padding(?:-(?:top|left|bottom|right))?',
    );
    $nZeroSafeProperties = array(
      'margin',
      'padding',
      'background-position',
    );
    $regStart = '/(;|\\{)';
    $regEnd = '/i';

    // First zero regex start
    $oneZeroRegStart = $regStart . '(' . implode('|', $oneZeroSafeProperties) . '):';

    // Multiple zeros regex start
    $nZerosRegStart = $regStart . '(' . implode('|', $nZeroSafeProperties) . '):';
    $css = preg_replace(array(
      $oneZeroRegStart . '0' . $unitsGroupReg . $regEnd,
      $nZerosRegStart . $numOrPosReg . ' 0' . $unitsGroupReg . $regEnd,
      $nZerosRegStart . $numOrPosReg . ' ' . $numOrPosReg . ' 0' . $unitsGroupReg . $regEnd,
      $nZerosRegStart . $numOrPosReg . ' ' . $numOrPosReg . ' ' . $numOrPosReg . ' 0' . $unitsGroupReg . $regEnd,
    ), array(
      '$1$2:0',
      '$1$2:$3 0',
      '$1$2:$3 $4 0',
      '$1$2:$3 $4 $5 0',
    ), $css);

    // Remove background-position
    array_pop($nZeroSafeProperties);

    // Replace 0 0; or 0 0 0; or 0 0 0 0; with 0 for safe properties only.
    $css = preg_replace('/(' . implode('|', $nZeroSafeProperties) . '):0(?: 0){1,3}(;|\\}| !)' . $regEnd, '$1:0$2', $css);

    // Replace 0 0 0; or 0 0 0 0; with 0 0 for background-position property.
    $css = preg_replace('/(background-position):0(?: 0){2,3}(;|\\}| !)' . $regEnd, '$1:0 0$2', $css);
    return $css;
  }

  /**
   * Shortens all named colors with a shorter HEX counterpart for a set of safe properties
   * e.g. white -> #fff
   * @param string $css
   * @return string
   */
  private function shortenNamedColors($css) {
    $patterns = array();
    $replacements = array();
    $longNamedColors = array(
      'aliceblue' => '#f0f8ff',
      'antiquewhite' => '#faebd7',
      'aquamarine' => '#7fffd4',
      'black' => '#000',
      'blanchedalmond' => '#ffebcd',
      'blueviolet' => '#8a2be2',
      'burlywood' => '#deb887',
      'cadetblue' => '#5f9ea0',
      'chartreuse' => '#7fff00',
      'chocolate' => '#d2691e',
      'cornflowerblue' => '#6495ed',
      'cornsilk' => '#fff8dc',
      'darkblue' => '#00008b',
      'darkcyan' => '#008b8b',
      'darkgoldenrod' => '#b8860b',
      'darkgray' => '#a9a9a9',
      'darkgreen' => '#006400',
      'darkgrey' => '#a9a9a9',
      'darkkhaki' => '#bdb76b',
      'darkmagenta' => '#8b008b',
      'darkolivegreen' => '#556b2f',
      'darkorange' => '#ff8c00',
      'darkorchid' => '#9932cc',
      'darksalmon' => '#e9967a',
      'darkseagreen' => '#8fbc8f',
      'darkslateblue' => '#483d8b',
      'darkslategray' => '#2f4f4f',
      'darkslategrey' => '#2f4f4f',
      'darkturquoise' => '#00ced1',
      'darkviolet' => '#9400d3',
      'deeppink' => '#ff1493',
      'deepskyblue' => '#00bfff',
      'dodgerblue' => '#1e90ff',
      'firebrick' => '#b22222',
      'floralwhite' => '#fffaf0',
      'forestgreen' => '#228b22',
      'fuchsia' => '#f0f',
      'gainsboro' => '#dcdcdc',
      'ghostwhite' => '#f8f8ff',
      'goldenrod' => '#daa520',
      'greenyellow' => '#adff2f',
      'honeydew' => '#f0fff0',
      'indianred' => '#cd5c5c',
      'lavender' => '#e6e6fa',
      'lavenderblush' => '#fff0f5',
      'lawngreen' => '#7cfc00',
      'lemonchiffon' => '#fffacd',
      'lightblue' => '#add8e6',
      'lightcoral' => '#f08080',
      'lightcyan' => '#e0ffff',
      'lightgoldenrodyellow' => '#fafad2',
      'lightgray' => '#d3d3d3',
      'lightgreen' => '#90ee90',
      'lightgrey' => '#d3d3d3',
      'lightpink' => '#ffb6c1',
      'lightsalmon' => '#ffa07a',
      'lightseagreen' => '#20b2aa',
      'lightskyblue' => '#87cefa',
      'lightslategray' => '#778899',
      'lightslategrey' => '#778899',
      'lightsteelblue' => '#b0c4de',
      'lightyellow' => '#ffffe0',
      'limegreen' => '#32cd32',
      'mediumaquamarine' => '#66cdaa',
      'mediumblue' => '#0000cd',
      'mediumorchid' => '#ba55d3',
      'mediumpurple' => '#9370db',
      'mediumseagreen' => '#3cb371',
      'mediumslateblue' => '#7b68ee',
      'mediumspringgreen' => '#00fa9a',
      'mediumturquoise' => '#48d1cc',
      'mediumvioletred' => '#c71585',
      'midnightblue' => '#191970',
      'mintcream' => '#f5fffa',
      'mistyrose' => '#ffe4e1',
      'moccasin' => '#ffe4b5',
      'navajowhite' => '#ffdead',
      'olivedrab' => '#6b8e23',
      'orangered' => '#ff4500',
      'palegoldenrod' => '#eee8aa',
      'palegreen' => '#98fb98',
      'paleturquoise' => '#afeeee',
      'palevioletred' => '#db7093',
      'papayawhip' => '#ffefd5',
      'peachpuff' => '#ffdab9',
      'powderblue' => '#b0e0e6',
      'rebeccapurple' => '#663399',
      'rosybrown' => '#bc8f8f',
      'royalblue' => '#4169e1',
      'saddlebrown' => '#8b4513',
      'sandybrown' => '#f4a460',
      'seagreen' => '#2e8b57',
      'seashell' => '#fff5ee',
      'slateblue' => '#6a5acd',
      'slategray' => '#708090',
      'slategrey' => '#708090',
      'springgreen' => '#00ff7f',
      'steelblue' => '#4682b4',
      'turquoise' => '#40e0d0',
      'white' => '#fff',
      'whitesmoke' => '#f5f5f5',
      'yellow' => '#ff0',
      'yellowgreen' => '#9acd32',
    );
    $propertiesWithColors = array(
      'color',
      'background(?:-color)?',
      'border(?:-(?:top|right|bottom|left|color)(?:-color)?)?',
      'outline(?:-color)?',
      '(?:text|box)-shadow',
    );
    $regStart = '/(;|\\{)(' . implode('|', $propertiesWithColors) . '):([^;}]*)\\b';
    $regEnd = '\\b/iS';
    foreach ($longNamedColors as $colorName => $colorCode) {
      $patterns[] = $regStart . $colorName . $regEnd;
      $replacements[] = '$1$2:$3' . $colorCode;
    }

    // Run at least 4 times to cover most cases (same color used several times for the same property)
    for ($i = 0; $i < 4; $i++) {
      $css = preg_replace($patterns, $replacements, $css);
    }
    return $css;
  }

  /**
   * Compresses HEX color values of the form #AABBCC to #ABC or short color name.
   *
   * DOES NOT compress CSS ID selectors which match the above pattern (which would break things).
   * e.g. #AddressForm { ... }
   *
   * DOES NOT compress IE filters, which have hex color values (which would break things).
   * e.g. filter: chroma(color="#FFFFFF");
   *
   * DOES NOT compress invalid hex values.
   * e.g. background-color: #aabbccdd
   *
   * @param string $css
   * @return string
   */
  private function shortenHexColors($css) {

    // Look for hex colors inside { ... } (to avoid IDs) and
    // which don't have a =, or a " in front of them (to avoid filters)
    $pattern = '/(=\\s*?["\']?)?#([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])(\\}|[^0-9a-f{][^{]*?\\})/iS';
    $_index = $index = $lastIndex = $offset = 0;
    $longHexColors = array(
      '#f0ffff' => 'azure',
      '#f5f5dc' => 'beige',
      '#ffe4c4' => 'bisque',
      '#a52a2a' => 'brown',
      '#ff7f50' => 'coral',
      '#ffd700' => 'gold',
      '#808080' => 'gray',
      '#008000' => 'green',
      '#4b0082' => 'indigo',
      '#fffff0' => 'ivory',
      '#f0e68c' => 'khaki',
      '#faf0e6' => 'linen',
      '#800000' => 'maroon',
      '#000080' => 'navy',
      '#fdf5e6' => 'oldlace',
      '#808000' => 'olive',
      '#ffa500' => 'orange',
      '#da70d6' => 'orchid',
      '#cd853f' => 'peru',
      '#ffc0cb' => 'pink',
      '#dda0dd' => 'plum',
      '#800080' => 'purple',
      '#f00' => 'red',
      '#fa8072' => 'salmon',
      '#a0522d' => 'sienna',
      '#c0c0c0' => 'silver',
      '#fffafa' => 'snow',
      '#d2b48c' => 'tan',
      '#008080' => 'teal',
      '#ff6347' => 'tomato',
      '#ee82ee' => 'violet',
      '#f5deb3' => 'wheat',
    );
    $sb = array();
    while (preg_match($pattern, $css, $m, 0, $offset)) {
      $index = $this
        ->indexOf($css, $m[0], $offset);
      $lastIndex = $index + strlen($m[0]);
      $isFilter = $m[1] !== null && $m[1] !== '';
      $sb[] = $this
        ->strSlice($css, $_index, $index);
      if ($isFilter) {

        // Restore, maintain case, otherwise filter will break
        $sb[] = $m[1] . '#' . $m[2] . $m[3] . $m[4] . $m[5] . $m[6] . $m[7];
      }
      else {
        if (strtolower($m[2]) == strtolower($m[3]) && strtolower($m[4]) == strtolower($m[5]) && strtolower($m[6]) == strtolower($m[7])) {

          // Compress.
          $hex = '#' . strtolower($m[3] . $m[5] . $m[7]);
        }
        else {

          // Non compressible color, restore but lower case.
          $hex = '#' . strtolower($m[2] . $m[3] . $m[4] . $m[5] . $m[6] . $m[7]);
        }

        // replace Hex colors with shorter color names
        $sb[] = array_key_exists($hex, $longHexColors) ? $longHexColors[$hex] : $hex;
      }
      $_index = $offset = $lastIndex - strlen($m[8]);
    }
    $sb[] = $this
      ->strSlice($css, $_index);
    return implode('', $sb);
  }

  // ---------------------------------------------------------------------------------------------
  // CALLBACKS
  // ---------------------------------------------------------------------------------------------
  private function processComments($matches) {
    $match = !empty($matches[1]) ? $matches[1] : '';
    return $this
      ->registerComment($match);
  }
  private function processStrings($matches) {
    $match = $matches[0];
    $quote = substr($match, 0, 1);
    $match = $this
      ->strSlice($match, 1, -1);

    // maybe the string contains a comment-like substring?
    // one, maybe more? put'em back then
    if (($pos = strpos($match, self::COMMENT)) !== false) {
      for ($i = 0, $max = count($this->comments); $i < $max; $i++) {
        $match = preg_replace($this
          ->getCommentPlaceholderRegexById($i), $this
          ->escapeReplacementString($this->comments[$i]), $match, 1);
      }
    }

    // minify alpha opacity in filter strings
    $match = preg_replace('/progid:DXImageTransform\\.Microsoft\\.Alpha\\(Opacity=/i', 'alpha(opacity=', $match);
    $preservedTokenPlaceholder = $this
      ->registerPreservedToken($match);
    return $quote . $preservedTokenPlaceholder . $quote;
  }
  private function processAtRuleBlocks($matches) {
    return $this
      ->registerAtRuleBlock($matches[0]);
  }
  private function processCalc($matches) {
    $token = preg_replace('/\\)([+\\-]{1})/', ') $1', preg_replace('/([+\\-]{1})\\(/', '$1 (', trim(preg_replace('/\\s*([*\\/(),])\\s*/', '$1', $matches[2]))));
    $preservedTokenPlaceholder = $this
      ->registerPreservedToken($token);
    return 'calc(' . $preservedTokenPlaceholder . ')';
  }
  private function processOldIeSpecificMatrixDefinition($matches) {
    $preservedTokenPlaceholder = $this
      ->registerPreservedToken($matches[1]);
    return 'filter:progid:DXImageTransform.Microsoft.Matrix(' . $preservedTokenPlaceholder . ')';
  }
  private function processColon($matches) {
    return preg_replace('/\\:/', self::CLASSCOLON, $matches[0]);
  }
  private function removeSpacesFromDataUrls($matches) {
    return preg_replace('/\\s+/', '', $matches[0]);
  }
  private function rgbToHex($matches) {
    $hexColors = array();
    $rgbColors = explode(',', $matches[1]);

    // Values outside the sRGB color space should be clipped (0-255)
    for ($i = 0, $l = count($rgbColors); $i < $l; $i++) {
      $hexColors[$i] = sprintf("%02x", $this
        ->clampNumberSrgb($this
        ->rgbPercentageToRgbInteger($rgbColors[$i])));
    }

    // Fix for issue #2528093
    if (!preg_match('/[\\s,);}]/', $matches[2])) {
      $matches[2] = ' ' . $matches[2];
    }
    return '#' . implode('', $hexColors) . $matches[2];
  }
  private function hslToHex($matches) {
    $hslValues = explode(',', $matches[1]);
    $rgbColors = $this
      ->hslToRgb($hslValues);
    return $this
      ->rgbToHex(array(
      '',
      implode(',', $rgbColors),
      $matches[2],
    ));
  }
  private function processAtRulesOperators($matches) {
    return $matches[1] . strtolower($matches[2]) . ' (';
  }
  private function lowercasePseudoFirst($matches) {
    return ':first-' . strtolower($matches[1]) . ' ' . $matches[2];
  }
  private function lowercaseDirectives($matches) {
    return '@' . strtolower($matches[1]);
  }
  private function lowercasePseudoElements($matches) {
    return ':' . strtolower($matches[1]);
  }
  private function lowercaseCommonFunctions($matches) {
    return ':' . strtolower($matches[1]) . '(';
  }
  private function lowercaseCommonFunctionsValues($matches) {
    return $matches[1] . strtolower($matches[2]);
  }
  private function lowercaseProperties($matches) {
    return $matches[1] . strtolower($matches[2]) . $matches[3];
  }

  // ---------------------------------------------------------------------------------------------
  // HELPERS
  // ---------------------------------------------------------------------------------------------

  /**
   * Clamps a number between a minimum and a maximum value.
   * @param int|float $n the number to clamp
   * @param int|float $min the lower end number allowed
   * @param int|float $max the higher end number allowed
   * @return int|float
   */
  private function clampNumber($n, $min, $max) {
    return min(max($n, $min), $max);
  }

  /**
   * Clamps a RGB color number outside the sRGB color space
   * @param int|float $n the number to clamp
   * @return int|float
   */
  private function clampNumberSrgb($n) {
    return $this
      ->clampNumber($n, 0, 255);
  }

  /**
   * Escapes backreferences such as \1 and $1 in a regular expression replacement string
   * @param $string
   * @return string
   */
  private function escapeReplacementString($string) {
    return addcslashes($string, '\\$');
  }

  /**
   * Converts a HSL color into a RGB color
   * @param array $hslValues
   * @return array
   */
  private function hslToRgb($hslValues) {
    $h = floatval($hslValues[0]);
    $s = floatval(str_replace('%', '', $hslValues[1]));
    $l = floatval(str_replace('%', '', $hslValues[2]));

    // Wrap and clamp, then fraction!
    $h = ($h % 360 + 360) % 360 / 360;
    $s = $this
      ->clampNumber($s, 0, 100) / 100;
    $l = $this
      ->clampNumber($l, 0, 100) / 100;
    if ($s == 0) {
      $r = $g = $b = $this
        ->roundNumber(255 * $l);
    }
    else {
      $v2 = $l < 0.5 ? $l * (1 + $s) : $l + $s - $s * $l;
      $v1 = 2 * $l - $v2;
      $r = $this
        ->roundNumber(255 * $this
        ->hueToRgb($v1, $v2, $h + 1 / 3));
      $g = $this
        ->roundNumber(255 * $this
        ->hueToRgb($v1, $v2, $h));
      $b = $this
        ->roundNumber(255 * $this
        ->hueToRgb($v1, $v2, $h - 1 / 3));
    }
    return array(
      $r,
      $g,
      $b,
    );
  }

  /**
   * Tests and selects the correct formula for each RGB color channel
   * @param $v1
   * @param $v2
   * @param $vh
   * @return mixed
   */
  private function hueToRgb($v1, $v2, $vh) {
    $vh = $vh < 0 ? $vh + 1 : ($vh > 1 ? $vh - 1 : $vh);
    if ($vh * 6 < 1) {
      return $v1 + ($v2 - $v1) * 6 * $vh;
    }
    if ($vh * 2 < 1) {
      return $v2;
    }
    if ($vh * 3 < 2) {
      return $v1 + ($v2 - $v1) * (2 / 3 - $vh) * 6;
    }
    return $v1;
  }

  /**
   * PHP port of Javascript's "indexOf" function for strings only
   * Author: Tubal Martin
   *
   * @param string $haystack
   * @param string $needle
   * @param int    $offset index (optional)
   * @return int
   */
  private function indexOf($haystack, $needle, $offset = 0) {
    $index = strpos($haystack, $needle, $offset);
    return $index !== false ? $index : -1;
  }

  /**
   * Convert strings like "64M" or "30" to int values
   * @param mixed $size
   * @return int
   */
  private function normalizeInt($size) {
    if (is_string($size)) {
      $letter = substr($size, -1);
      $size = intval($size);
      switch ($letter) {
        case 'M':
        case 'm':
          return (int) $size * 1048576;
        case 'K':
        case 'k':
          return (int) $size * 1024;
        case 'G':
        case 'g':
          return (int) $size * 1073741824;
      }
    }
    return (int) $size;
  }

  /**
   * Converts a string containing and RGB percentage value into a RGB integer value i.e. '90%' -> 229.5
   * @param $rgbPercentage
   * @return int
   */
  private function rgbPercentageToRgbInteger($rgbPercentage) {
    if (strpos($rgbPercentage, '%') !== false) {
      $rgbPercentage = $this
        ->roundNumber(floatval(str_replace('%', '', $rgbPercentage)) * 2.55);
    }
    return intval($rgbPercentage, 10);
  }

  /**
   * Rounds a number to its closest integer
   * @param $n
   * @return int
   */
  private function roundNumber($n) {
    return intval(round(floatval($n)), 10);
  }

  /**
   * PHP port of Javascript's "slice" function for strings only
   * Author: Tubal Martin
   *
   * @param string   $str
   * @param int      $start index
   * @param int|bool $end index (optional)
   * @return string
   */
  private function strSlice($str, $start = 0, $end = false) {
    if ($end !== false && ($start < 0 || $end <= 0)) {
      $max = strlen($str);
      if ($start < 0) {
        if (($start = $max + $start) < 0) {
          return '';
        }
      }
      if ($end < 0) {
        if (($end = $max + $end) < 0) {
          return '';
        }
      }
      if ($end <= $start) {
        return '';
      }
    }
    $slice = $end === false ? substr($str, $start) : substr($str, $start, $end - $start);
    return $slice === false ? '' : $slice;
  }

}

Classes

Name	Description
CSSmin