发现以下工作：
class RawData {
var data: NSData!
init(rawData: NSData) {
data = rawData
}
func read<T>(byteLocation: Int) -> T {
let bytes = data.subdataWithRange(NSMakeRange(byteLocation, sizeof(T))).bytes
return UnsafePointer<T>(bytes).memory
}
func example_ReadAnIntAtByteLocation5() -> Int {
return read(5) as Int
}
}在SWIFT有更好的方法吗？
@implementation RawDataOffsetPointer
inline void* offsetPointer(void* ptr, int bytes){
return (char*)ptr + bytes;
}
@end可以更改read方法
func read<T>(byteLocation: Int) -> T {
let ptr = offsetPointer(data.bytes, CInt(byteLocation))
return UnsafePointer<T>(ptr).memory
}
回答 2
类似这样：
func generateRandomData(count:Int) -> NSData
{
var array = Array<UInt8>(count: count, repeatedValue: 0)
arc4random_buf(&array, UInt(count))
return NSData(bytes: array, length: count)
}
let randomData = generateRandomData(256 * 1024)
let stream = NSInputStream(data: randomData)
stream.open() // IMPORTANT
var readBuffer = Array<UInt8>(count: 16 * 1024, repeatedValue: 0)
var totalBytesRead = 0
while (totalBytesRead < randomData.length)
{
let numberOfBytesRead = stream.read(&readBuffer, maxLength: readBuffer.count)
// Do something with the data
totalBytesRead += numberOfBytesRead
}可以创建一个extension，如下所示：
extension NSInputStream
{
func readInt32() -> Int
{
var readBuffer = Array<UInt8>(count:sizeof(Int32), repeatedValue: 0)
var numberOfBytesRead = self.read(&readBuffer, maxLength: readBuffer.count)
return Int(readBuffer[0]) << 24 |
Int(readBuffer[1]) << 16 |
Int(readBuffer[2]) << 8 |
Int(readBuffer[3])
}
}UnsafePointer<T>可以操纵：
let oldPointer = UnsafePointer<()>
let newPointer = oldPointer + 10还可以像这样转换一个指针
let castPointer = UnsafePointer<MyStruct>(oldPointer)和开发者交流更多问题细节吧，去 写回答
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