NSString, NSData, Byte 间不得不说的故事

最近比较懒啥都不说了直接上代码

OC

NSString *str;
NSData *data;
Byte byte[n];
    
// 1. NSString -> NSData
      data = [str dataUsingEncoding:NSUTF8StringEncoding];
    
// 2. NSData -> NSString
      str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    
// 3. NSString -> Byte
      [str getBytes:byte maxLength:str.length usedLength:nil encoding:NSUTF8StringEncoding options:NSStringEncodingConversionExternalRepresentation range:NSMakeRange(0, str.length) remainingRange:nil];
    
// 4. Byte -> NSString
      str = [[NSString alloc] initWithBytes:byte length:sizeof(byte) encoding:NSUTF8StringEncoding];
    
// 5. NSData -> Byte
      (1) const Byte *byteP = data.bytes;
      (2) [data getBytes:byte length:sizeof(byte)];
      
// 6. Byte -> NSData
      data = [NSData dataWithBytes:byte length:sizeof(byte)];

Swift

var str: String!
var data: Data!
var uInt8: [UInt8]!

// 1. String -> Data
   data = str.data(using: .utf8)
   
// 2. Data -> String
   str = String(data: data, encoding: .utf8)

// 3. String -> [UInt8]
   uInt8 = [UInt8](str.utf8)

// 4. [UInt8] -> String
   str = String(bytes: uInt8, encoding: .utf8)

// 5. Data -> [UInt8]
   uInt8 = [UInt8](data)
   
   (1): Data -> UnsafePointer<UInt8> 
        _ = data.withUnsafeBytes { (uInt8: UnsafePointer<UInt8>) -> ResultType in
           ...
        }
   (2): Data -> UnsafeMutablePointer<UInt8>
        data.copyBytes(to: &uInt8, count: uInt8.count)
   (3): UnsafeRawPointer -> UnsafePointer<UInt8>
        let nsData: NSData = ...
        let uInt8P = nsData.bytes.assumingMemoryBound(to: UInt8)
   
// 6. [UInt8] -> Data
   data = Data(bytes: uInt8)