postcss/lib/tokenize.js

var singleQuote = "'".charCodeAt(0),
    doubleQuote = '"'.charCodeAt(0),
    backslash   = '\\'.charCodeAt(0),
    slash       = '/'.charCodeAt(0),
    newline     = '\n'.charCodeAt(0),
    space       = ' '.charCodeAt(0),
    feed        = '\f'.charCodeAt(0),
    tab         = '\t'.charCodeAt(0),
    cr          = '\r'.charCodeAt(0),
    bracket     = '('.charCodeAt(0),
    openCurly   = '{'.charCodeAt(0),
    closeCurly  = '}'.charCodeAt(0),
    semicolon   = ';'.charCodeAt(0),
    asterisk    = '*'.charCodeAt(0),
    colon       = ':'.charCodeAt(0),
    at          = '@'.charCodeAt(0),
    atEnd       = /[ \n\t\r\{'"/]/g,
    wordEnd     = /[ \n\t\r\(\{\}:;@!'"]|\/(?=\*)/g;

module.exports = function (input) {
    var tokens = [];
    var css    = input.css.valueOf();

    var code, next, quote, lines, last, content,
        nextLine, nextOffset, escaped, escapePos;

    var offset  = -1;
    var line    =  1;
    var pos     =  0;

    var unclosed = function (what, end) {
        if ( input.safe ) {
            css += end;
            next = css.length - 1;
        } else {
            input.error('Unclosed ' + what, line, pos  - offset);
        }
    };

    while ( !Number.isNaN(code = css.charCodeAt(pos)) ) {

        if ( code == newline ) {
            offset = pos;
            line  += 1;
        }

        switch ( code ) {
            case newline:
            case space:
            case feed:
            case tab:
            case cr:
                next = pos;
                do {
                    next += 1;
                    code = css.charCodeAt(next);
                    if ( code == newline ) {
                        offset = next;
                        line  += 1;
                    }
                } while ( code == space   ||
                          code == newline ||
                          code == tab     ||
                          code == cr      ||
                          code == feed );

                tokens.push(['space', css.slice(pos, next)]);
                pos = next - 1;
                break;

            case openCurly:
                tokens.push(['{', '{', line, pos - offset]);
                break;

            case closeCurly:
                tokens.push(['}', '}', line, pos - offset]);
                break;

            case colon:
                tokens.push([':', ':', line, pos - offset]);
                break;

            case semicolon:
                tokens.push([';', ';', line, pos - offset]);
                break;

            case singleQuote:
            case doubleQuote:
                if ( code == singleQuote ) {
                    quote = "'";
                } else {
                    quote = '"';
                }

                next = pos;
                do {
                    escaped = false;
                    next    = css.indexOf(quote, next + 1);
                    if ( next == -1 ) unclosed('quote', quote);
                    escapePos = next;
                    while ( css.charCodeAt(escapePos - 1) == backslash ) {
                        escapePos -= 1;
                        escaped = !escaped;
                    }
                } while ( escaped );

                tokens.push([
                    'string',
                    css.slice(pos, next + 1),
                    line, pos  - offset,
                    line, next - offset
                ]);
                pos = next;
                break;

            case bracket:
                next = pos;

                do {
                    escaped = false;
                    next = css.indexOf(')', next + 1);
                    if ( next == -1 ) unclosed('bracket', ')');
                    escapePos = next;
                    while ( css.charCodeAt(escapePos - 1) == backslash ) {
                        escapePos -= 1;
                        escaped = !escaped;
                    }
                } while (escaped);

                content = css.slice(pos, next + 1);
                lines   = content.split('\n');
                last    = lines.length - 1;

                if ( last > 0 ) {
                    nextLine   = line + last;
                    nextOffset = next - lines[last].length;
                } else {
                    nextLine   = line;
                    nextOffset = offset;
                }

                tokens.push([
                    'brackets',
                    content,
                    line,     pos  - offset,
                    nextLine, next - nextOffset
                ]);

                offset = nextOffset;
                line   = nextLine;
                pos    = next;
                break;

            case at:
                atEnd.lastIndex = pos + 1;
                atEnd.test(css);
                if ( atEnd.lastIndex === 0 ) {
                    next = css.length - 1;
                } else {
                    next = atEnd.lastIndex - 2;
                }
                tokens.push([
                    'at-word',
                    css.slice(pos, next + 1),
                    line, pos  - offset,
                    line, next - offset
                ]);
                pos = next;
                break;

            default:
                if ( code == slash && css.charCodeAt(pos + 1) == asterisk ) {
                    next = css.indexOf('*/', pos + 2) + 1;
                    if ( next === 0 ) unclosed('comment', '*/');

                    content = css.slice(pos, next + 1);
                    lines   = content.split('\n');
                    last    = lines.length - 1;

                    if ( last > 0 ) {
                        nextLine   = line + last;
                        nextOffset = next - lines[last].length;
                    } else {
                        nextLine   = line;
                        nextOffset = offset;
                    }

                    tokens.push([
                        'comment',
                        content,
                        line,     pos  - offset,
                        nextLine, next - nextOffset
                    ]);

                    offset = nextOffset;
                    line   = nextLine;
                    pos    = next;

                } else {
                    wordEnd.lastIndex = pos + 1;
                    wordEnd.test(css);
                    if ( wordEnd.lastIndex === 0 ) {
                        next = css.length - 1;
                    } else {
                        next = wordEnd.lastIndex - 2;
                    }

                    tokens.push([
                        'word',
                        css.slice(pos, next + 1),
                        line, pos  - offset,
                        line, next - offset
                    ]);
                    pos = next;
                }

                break;
        }

        pos++;
    }

    return tokens;
};