function generateRegExp()

in benchmark/old.js [417:463]
37 lines of code
9 McCabe index (conditional complexity)

    function generateRegExp(reg) {
        var match, result, flags, i, iz, ch, characterInBrack, previousIsBackslash;

        result = reg.toString();

        if (reg.source) {
            // extract flag from toString result
            match = result.match(/\/([^/]*)$/);
            if (!match) {
                return result;
            }

            flags = match[1];
            result = '';

            characterInBrack = false;
            previousIsBackslash = false;
            for (i = 0, iz = reg.source.length; i < iz; ++i) {
                ch = reg.source.charCodeAt(i);

                if (!previousIsBackslash) {
                    if (characterInBrack) {
                        if (ch === 93) {  // ]
                            characterInBrack = false;
                        }
                    } else {
                        if (ch === 47) {  // /
                            result += '\\';
                        } else if (ch === 91) {  // [
                            characterInBrack = true;
                        }
                    }
                    result += escapeRegExpCharacter(ch, previousIsBackslash);
                    previousIsBackslash = ch === 92;  // \
                } else {
                    // if new RegExp("\\\n') is provided, create /\n/
                    result += escapeRegExpCharacter(ch, previousIsBackslash);
                    // prevent like /\\[/]/
                    previousIsBackslash = false;
                }
            }

            return '/' + result + '/' + flags;
        }

        return result;
    }