ios - Cannot Initialise Variable for type Unsafepointer Swift 3.0 conversion -

hi converting existing swift 2.0 code swift 3.0 came across error while conversion:

cannot invoke initializer type 'unsafepointer' argument list of type '(unsaferawpointer)'

here code:

extension data {    var hexstring : string {     let buf = unsafepointer<uint8>(bytes) // here error     let chara = uint8(unicodescalar("a").value)     let char0 = uint8(unicodescalar("0").value)      func itoh(_ i: uint8) -> uint8 {         return (i > 9) ? (chara + - 10) : (char0 + i)     }      let p = unsafemutablepointer<uint8>.allocate(capacity: count * 2)      in 0..<count {         p[i*2] = itoh((buf[i] >> 4) & 0xf)         p[i*2+1] = itoh(buf[i] & 0xf)     }      return nsstring(bytesnocopy: p, length: count*2, encoding: string.encoding.utf8.rawvalue, freewhendone: true)! string  } } 

in swift 3 have use withunsafebytes() access raw bytes of data value. in case:

withunsafebytes { (buf: unsafepointer<uint8>) in     in 0..<count {         p[i*2] = itoh((buf[i] >> 4) & 0xf)         p[i*2+1] = itoh(buf[i] & 0xf)     } } 

alternatively, use fact data collection of bytes:

for (i, byte) in self.enumerated() {     p[i*2] = itoh((byte >> 4) & 0xf)     p[i*2+1] = itoh(byte & 0xf) } 

note there problem in code:

nsstring(..., freewhendone: true) 

uses free() release memory, means must allocated malloc().

other (shorter, potentially less efficient) methods create hex representation of data value can found @ how convert data hex string in swift.