minifyCSS.js

// Copyright (c) 2010, edvakf
// algorithm from http://www.ko-sw.com/Blog/post/An-Ultra-Fast-CSS-Minify-Algorithm.aspx
/*
* Copyright (c) 2010, KO Software (official@koapproach.com)
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
*     * All original and modified versions of this source code must include the
*       above copyright notice, this list of conditions and the following
*       disclaimer.
*
*     * This code may not be used with or within any modules or code that is 
*       licensed in any way that that compels or requires users or modifiers
*       to release their source code or changes as a requirement for
*       the use, modification or distribution of binary, object or source code
*       based on the licensed source code. (ex: Cannot be used with GPL code.)
*
*     * The name of KO Software may be used to endorse or promote products
*       derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY KO SOFTWARE ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT WILL KO SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

function minifyCSS(css) {
  var 
  output = '',
  len = css.length,
  Punctuation = 1, Token = 2, StringD = 3, StringS = 4,
  state = Punctuation,
  oldpos = 0, pos = 0;

  while (oldpos < len) {
    var newstate = getState();
    if (pos > oldpos + 1) {
      // if whitespace is found between two tokens, keep it compact
      if (state === Token && newstate === Token) output += ' ';
    }
    if (pos === len) break;
    oldpos = pos;
    state = newstate;
    // remove ";" as of "foo:bar;}"
    if (state === Punctuation && css[pos] === '}' && output[output.length - 1] === ';') output = output.slice(0, -1);
    output += css[pos++];
  }
  return output;

  // getState changes the value of pos and returns a state
  function getState() {
    var i = pos;
    if (state === StringD) {
      return (css[i] === '"' && !(pos > 0 && css[i-1] === '\\')) ? Token : StringD;
    } else if (state === StringS) {
      return (css[i] === "'" && !(pos > 0 && css[i-1] === '\\')) ? Token : StringS;
    }

    skip = true;
    while (skip) {
      // skip whitespaces
      while (skip = (i < len && /[ \t\r\n]/.test(css[i]))) i++;
      // skip comments
      if (i < len - 1 && css[i] === '/' && css[i+1] === '*') {
        skip = true;
        while (i < len) {
          i++;
          if (css[i-1] === '*' && css[i] === '/') {
            i++;
            break;
          }
        }
      }
    }

    pos = i;
    if (/[a-zA-Z0-9#_@*.-]/.test(css[i])) {
      return (state === StringD) ? StringD : Token;
    } else if (css[i] === '"') {
      return StringD;
    } else if (css[i] === "'") {
      return StringS;
    } else {
      return Punctuation;
    }
  }
}