cssmin.js
  Author: Stoyan Stefanov - http://phpied.com/
  This is a JavaScript 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 JavaScript version under the same
  conditions as the YUICompressor (original YUICompressor note below).

 YUI Compressor
 http://developer.yahoo.com/yui/compressor/
 Author: Julien Lecomte - http://www.julienlecomte.net/
 Copyright (c) 2011 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.
/

var YAHOO = YAHOO || {}; YAHOO.compressor = YAHOO.compressor || {};

/**

 Utility method to replace all data urls with tokens before we start
 compressing, to avoid performance issues running some of the subsequent
 regexes against large strings chunks.

 @private
 @method _extractDataUrls
 @param {String} css The input css
 @param {Array} The global array of tokens to preserve
 @returns String The processed css
/

YAHOO.compressor._extractDataUrls = function (css, preservedTokens) {

// Leave data urls alone to increase parse performance.
var maxIndex = css.length - 1,
    appendIndex = 0,
    startIndex,
    endIndex,
    terminator,
    foundTerminator,
    sb = [],
    m,
    preserver,
    token,
    pattern = /url\(\s*(["']?)data\:/g;

// 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 ((m = pattern.exec(css)) !== null) {

    startIndex = m.index + 4;  // "url(".length()
    terminator = m[1];         // ', " or empty (not quoted)

    if (terminator.length === 0) {
        terminator = ")";
    }

    foundTerminator = false;

    endIndex = pattern.lastIndex - 1;

    while(foundTerminator === false && endIndex+1 <= maxIndex) {
        endIndex = css.indexOf(terminator, endIndex + 1);

        // endIndex == 0 doesn't really apply here
        if ((endIndex > 0) && (css.charAt(endIndex - 1) !== '\\')) {
            foundTerminator = true;
            if (")" != terminator) {
                endIndex = css.indexOf(")", endIndex); 
            }
        }
    }

    // Enough searching, start moving stuff over to the buffer
    sb.push(css.substring(appendIndex, m.index));

    if (foundTerminator) {
        token = css.substring(startIndex, endIndex);
        token = token.replace(/\s+/g, "");
        preservedTokens.push(token);

        preserver = "url(___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___)";
        sb.push(preserver);

        appendIndex = endIndex + 1;
    } else {
        // No end terminator found, re-add the whole match. Should we throw/warn here?
        sb.push(css.substring(m.index, pattern.lastIndex));
        appendIndex = pattern.lastIndex;
    }
}

sb.push(css.substring(appendIndex));

return sb.join("");

};

/**

 Utility method to compress hex color values of the form #AABBCC to #ABC.

 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

 @private
 @method _compressHexColors
 @param {String} css The input css
 @returns String The processed css
/

YAHOO.compressor._compressHexColors = function(css) {

// Look for hex colors inside { ... } (to avoid IDs) and which don't have a =, or a " in front of them (to avoid filters)
var pattern = /(\=\s*?["']?)?#([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])(\}|[^0-9a-f{][^{]*?\})/gi,
    m,
    index = 0,
    isFilter,
    sb = [];

while ((m = pattern.exec(css)) !== null) {

    sb.push(css.substring(index, m.index));

    isFilter = m[1];

    if (isFilter) {
        // Restore, maintain case, otherwise filter will break
        sb.push(m[1] + "#" + (m[2] + m[3] + m[4] + m[5] + m[6] + m[7]));
    } else {
        if (m[2].toLowerCase() == m[3].toLowerCase() &&
            m[4].toLowerCase() == m[5].toLowerCase() &&
            m[6].toLowerCase() == m[7].toLowerCase()) {

            // Compress.
            sb.push("#" + (m[3] + m[5] + m[7]).toLowerCase());
        } else {
            // Non compressible color, restore but lower case.
            sb.push("#" + (m[2] + m[3] + m[4] + m[5] + m[6] + m[7]).toLowerCase());
        }
    }

    index = pattern.lastIndex = pattern.lastIndex - m[8].length;
}

sb.push(css.substring(index));

return sb.join("");

};

YAHOO.compressor.cssmin = function (css, linebreakpos) {

var startIndex = 0,
    endIndex = 0,
    i = 0, max = 0,
    preservedTokens = [],
    comments = [],
    token = '',
    totallen = css.length,
    placeholder = '';

css = this._extractDataUrls(css, preservedTokens);

// collect all comment blocks...
while ((startIndex = css.indexOf("/*", startIndex)) >= 0) {
    endIndex = css.indexOf("  ", startIndex + 2);
    if (endIndex < 0) {
        endIndex = totallen;
    }
    token = css.slice(startIndex + 2, endIndex);
    comments.push(token);
    css = css.slice(0, startIndex + 2) + "___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + (comments.length - 1) + "___" + css.slice(endIndex);
    startIndex += 2;
}

// preserve strings so their content doesn't get accidentally minified
css = css.replace(/("([^\"]|\.|\)*")|('([^\\']|\.|\)*')/g, function (match) {
    var i, max, quote = match.substring(0, 1);

    match = match.slice(1, -1);

    // maybe the string contains a comment-like substring?
    // one, maybe more? put'em back then
    if (match.indexOf("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_") >= 0) {
        for (i = 0, max = comments.length; i < max; i = i + 1) {
            match = match.replace("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___", comments[i]);
        }
    }

    // minify alpha opacity in filter strings
    match = match.replace(/progid:DXImageTransform\.Microsoft\.Alpha\(Opacity=/gi, "alpha(opacity=");

    preservedTokens.push(match);
    return quote + "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___" + quote;
});

// strings are safe, now wrestle the comments
for (i = 0, max = comments.length; i < max; i = i + 1) {

    token = comments[i];
    placeholder = "___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___";

    // ! in the first position of the comment means preserve
    // so push to the preserved tokens keeping the !
    if (token.charAt(0) === "!") {
        preservedTokens.push(token);
        css = css.replace(placeholder,  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___");
        continue;
    }

    // \ in the last position looks like hack for Mac/IE5
    // shorten that to /*\*/ and the next one to /**/
    if (token.charAt(token.length - 1) === "\") {
        preservedTokens.push("\");
        css = css.replace(placeholder,  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___");
        i = i + 1; // attn: advancing the loop
        preservedTokens.push("");
        css = css.replace("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___",  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___");
        continue;
    }

    // keep empty comments after child selectors (IE7 hack)
    // e.g. html >/**/ body
    if (token.length === 0) {
        startIndex = css.indexOf(placeholder);
        if (startIndex > 2) {
            if (css.charAt(startIndex - 3) === '>') {
                preservedTokens.push("");
                css = css.replace(placeholder,  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___");
            }
        }
    }

    // in all other cases kill the comment
    css = css.replace("/*" + placeholder + "*/", "");
}

// Normalize all whitespace strings to single spaces. Easier to work with that way.
css = css.replace(/\s+/g, " ");

// 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 = css.replace(/(^|\})(([^\{:])+:)+([^\{]*\{)/g, function (m) {
    return m.replace(":", "___YUICSSMIN_PSEUDOCLASSCOLON___");
});
css = css.replace(/\s+([!{};:>+\(\)\],])/g, '$1');
css = css.replace(/___YUICSSMIN_PSEUDOCLASSCOLON___/g, ":");

// retain space for special IE6 cases
css = css.replace(/:first-(line|letter)(\{|,)/g, ":first-$1 $2");

// no space after the end of a preserved comment
css = css.replace(/\*\/ /g, '*/');

// If there is a @charset, then only allow one, and push to the top of the file.
css = css.replace(/^(.*)(@charset "[^"]*";)/gi, '$2$1');
css = css.replace(/^(\s*@charset [^;]+;\s*)+/gi, '$1');

// Put the space back in some cases, to support stuff like
// @media screen and (-webkit-min-device-pixel-ratio:0){
css = css.replace(/\band\(/gi, "and (");

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

// remove unnecessary semicolons
css = css.replace(/;+\}/g, "}");

// Replace 0(px,em,%Q( with 0.
css = css.replace(/([\s:])(0)(px|em|%|in|cm|mm|pc|pt|ex)/gi, "$1$2");

// Replace 0 0 0 0; with 0.
css = css.replace(/:0 0 0 0(;|\})/g, ":0$1");
css = css.replace(/:0 0 0(;|\})/g, ":0$1");
css = css.replace(/:0 0(;|\})/g, ":0$1");

// Replace background-position:0; with background-position:0 0;
// same for transform-origin
css = css.replace(/(background-position|transform-origin|webkit-transform-origin|moz-transform-origin|o-transform-origin|ms-transform-origin):0(;|\})/gi, function(all, prop, tail) {
    return prop.toLowerCase() + ":0 0" + tail;
});

// Replace 0.6 to .6, but only when preceded by : or a white-space
css = css.replace(/(:|\s)0+\.(\d+)/g, "$1.$2");

// Shorten colors from rgb(51,102,153) to #336699
// This makes it more likely that it'll get further compressed in the next step.
css = css.replace(/rgb\s*\(\s*([0-9,\s]+)\s*\)/gi, function () {
    var i, rgbcolors = arguments[1].split(',');
    for (i = 0; i < rgbcolors.length; i = i + 1) {
        rgbcolors[i] = parseInt(rgbcolors[i], 10).toString(16);
        if (rgbcolors[i].length === 1) {
            rgbcolors[i] = '0' + rgbcolors[i];
        }
    }
    return '#' + rgbcolors.join('');
});

// Shorten colors from #AABBCC to #ABC.
css = this._compressHexColors(css);

// border: none -> border:0
css = css.replace(/(border|border-top|border-right|border-bottom|border-right|outline|background):none(;|\})/gi, function(all, prop, tail) {
    return prop.toLowerCase() + ":0" + tail;
});

// shorter opacity IE filter
css = css.replace(/progid:DXImageTransform\.Microsoft\.Alpha\(Opacity=/gi, "alpha(opacity=");

// Remove empty rules.
css = css.replace(/[^\};\{\/]+\{\}/g, "");

if (linebreakpos >= 0) {
    // 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.
    startIndex = 0;
    i = 0;
    while (i < css.length) {
        i = i + 1;
        if (css[i - 1] === '}' && i - startIndex > linebreakpos) {
            css = css.slice(0, i) + '\n' + css.slice(i);
            startIndex = i;
        }
    }
}

// Replace multiple semi-colons in a row by a single one
// See SF bug #1980989
css = css.replace(/;;+/g, ";");

// restore preserved comments and strings
for (i = 0, max = preservedTokens.length; i < max; i = i + 1) {
    css = css.replace("___YUICSSMIN_PRESERVED_TOKEN_" + i + "___", preservedTokens[i]);
}

// Trim the final string (for any leading or trailing white spaces)
css = css.replace(/^\s+|\s+$/g, "");

return css;

};

exports.compressor = YAHOO.compressor;