来自十六进制字符串的 NSData?
NSData from hex String?
我知道 ObjectiveC
已经问过这个问题,但我的 Swift
还不够强大,无法音译 char *bytes
内容。
如此给出
let string = "600DBEEF"
如何创建代表这 4 个字节的 NSData
:60 0D BE EF
?
在 swift、XCode beta 6
中回答
let string = "600DBEEF"
let length = string.characters.count
let rawData = UnsafeMutablePointer<CUnsignedChar>.alloc(length/2)
var rawIndex = 0
for var index = 0; index < length; index+=2{
let single = NSMutableString()
single.appendString(string.substringWithRange(Range(start:string.startIndex.advancedBy(index), end:string.startIndex.advancedBy(index+2))))
rawData[rawIndex] = UInt8(single as String, radix:16)!
rawIndex++
}
let data:NSData = NSData(bytes: rawData, length: length/2)
rawData.dealloc(length/2)
随着 Swift3 和新的 Foundation Data 类型的到来,我终于回到了这里:
extension UnicodeScalar {
var hexNibble:UInt8 {
let value = self.value
if 48 <= value && value <= 57 {
return UInt8(value - 48)
}
else if 65 <= value && value <= 70 {
return UInt8(value - 55)
}
else if 97 <= value && value <= 102 {
return UInt8(value - 87)
}
fatalError("\(self) not a legal hex nibble")
}
}
extension Data {
init(hex:String) {
let scalars = hex.unicodeScalars
var bytes = Array<UInt8>(repeating: 0, count: (scalars.count + 1) >> 1)
for (index, scalar) in scalars.enumerated() {
var nibble = scalar.hexNibble
if index & 1 == 0 {
nibble <<= 4
}
bytes[index >> 1] |= nibble
}
self = Data(bytes: bytes)
}
}
现在我可以以类似于打印形式的方式构造 Data 对象:
Data(hex: "600dBeef")
我知道 ObjectiveC
已经问过这个问题,但我的 Swift
还不够强大,无法音译 char *bytes
内容。
如此给出
let string = "600DBEEF"
如何创建代表这 4 个字节的 NSData
:60 0D BE EF
?
在 swift、XCode beta 6
中回答 let string = "600DBEEF"
let length = string.characters.count
let rawData = UnsafeMutablePointer<CUnsignedChar>.alloc(length/2)
var rawIndex = 0
for var index = 0; index < length; index+=2{
let single = NSMutableString()
single.appendString(string.substringWithRange(Range(start:string.startIndex.advancedBy(index), end:string.startIndex.advancedBy(index+2))))
rawData[rawIndex] = UInt8(single as String, radix:16)!
rawIndex++
}
let data:NSData = NSData(bytes: rawData, length: length/2)
rawData.dealloc(length/2)
随着 Swift3 和新的 Foundation Data 类型的到来,我终于回到了这里:
extension UnicodeScalar {
var hexNibble:UInt8 {
let value = self.value
if 48 <= value && value <= 57 {
return UInt8(value - 48)
}
else if 65 <= value && value <= 70 {
return UInt8(value - 55)
}
else if 97 <= value && value <= 102 {
return UInt8(value - 87)
}
fatalError("\(self) not a legal hex nibble")
}
}
extension Data {
init(hex:String) {
let scalars = hex.unicodeScalars
var bytes = Array<UInt8>(repeating: 0, count: (scalars.count + 1) >> 1)
for (index, scalar) in scalars.enumerated() {
var nibble = scalar.hexNibble
if index & 1 == 0 {
nibble <<= 4
}
bytes[index >> 1] |= nibble
}
self = Data(bytes: bytes)
}
}
现在我可以以类似于打印形式的方式构造 Data 对象:
Data(hex: "600dBeef")