Rainbow.swift

struct ConsoleModesExtractor: ModesExtractor {
    typealias ResultType = UInt8
    func extractModeCodes(string: String) -> (codes: [UInt8], text: String) {
        let token = ControlCode.CSI
        var index = string.startIndex.advancedBy(token.characters.count)
        var codesString = ""
        while string.characters[index] != "m" {
            codesString.append(string.characters[index])
            index = index.successor()
        }
        
        let codes = codesString.characters.split(separator: ";", maxSplits: Int.max, omittingEmptySubsequences: false)
        
        let startIndex = index.successor()
        string.endIndex
        let endIndex = string.endIndex.advancedBy(-"\(token)0m".characters.count)
        let text = String(string.characters[startIndex ..< endIndex])
        
        return (codes, text)
    }
}