Swift中GBK编码转换

import Foundation

extension String {
    init?(gbkData: Data) {
        //获取GBK编码, 使用GB18030是因为它向下兼容GBK
        let cfEncoding = CFStringEncodings.GB_18030_2000
        let encoding = CFStringConvertEncodingToNSStringEncoding(CFStringEncoding(cfEncoding.rawValue))
        //从GBK编码的Data里初始化NSString, 返回的NSString是UTF-16编码
        if let str = NSString(data: gbkData, encoding: encoding) {
            self = str as String
        } else {
            return nil
        }
    }
    
    var gbkData: Data {
        let cfEncoding = CFStringEncodings.GB_18030_2000
        let encoding = CFStringConvertEncodingToNSStringEncoding(CFStringEncoding(cfEncoding.rawValue))
        let gbkData = (self as NSString).data(using: encoding)!
        return gbkData
    }
    
}


var str = "你好123"
print(str.gbkData.count)