iOS Base64编解码

<pre name="code" class="html">NSData *plainData = [plainString dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64String = [plainData base64EncodedStringWithOptions:0];
NSLog(@"%@", base64String);// Zm9v

NSData *decodedData = [[NSData alloc] initWithBase64EncodedString:base64String options:0];
NSString *decodedString = [[NSString alloc] initWithData:decodedData encoding:NSUTF8StringEncoding];
NSLog(@"%@", decodedString); // foo

let plainData = plainString.dataUsingEncoding(NSUTF8StringEncoding)
let base64String = plainData?.base64EncodedStringWithOptions(.allZeros)
println(base64String!) // Zm9v

let decodedData = NSData(base64EncodedString: base64String!, options: .allZeros)
let decodedString = NSString(data: decodedData, encoding: NSUTF8StringEncoding)
println(decodedString) // foo