您好我是swift的新手,想将一个字节数组转换为几个整数。我用Java编写了工作代码,但我不太确定如何将其用于快速
byte[] codeData = Base64.decode(codeDataBase64, 0);
ByteArrayInputStream bais = new ByteArrayInputStream(codeData);
DataInputStream dis = new DataInputStream(bais);
byte version = dis.readByte();
if (version == 1) {
int anID = dis.readInt();
int anotherID = dis.readInt();
byte[] TK = new byte[512];
int readTK = dis.read(TK);
if (readTK == TK.length) {
Log.e("photoConnect success", "anID=" + anID + ", anotherID=" + anotherID + ", TK.length=" + TK.length);
这是我到目前为止在Swift中所拥有的:
func base64ToByteArray(base64String: String) -> [UInt8]? {
if let nsdata = NSData(base64Encoded: base64String) {
var bytes = [UInt8](repeating: 0, count: nsdata.length)
nsdata.getBytes(&bytes, length: nsdata.length)
return bytes
}
return nil // Invalid input
}
这个函数将它带到一个字节数组但我不确定用什么Swift类来模仿Java中DataInputStream的行为。
答案 0 :(得分:0)
好的,我有一个有效的解决方案。非常感谢Martin R向我展示他上面链接的帖子(Idiomatic method of parsing swift(3) data streams)
我基本上从Martin R链接的类中取出并修改它以使用NSData对象而不是Data对象: class DataStream { 让数据:NSData var index = 0 var atEnd:Bool { return index> = self.data.length }
init(data:NSData) {
self.data = data
}
func next() -> UInt8? {
guard !self.atEnd else { return nil }
let byte = self.data.subdata(with: NSRange(location: self.index, length: 1))[0]
self.index += 1
return byte
}
func next(_ count:Int) -> NSData? {
guard self.index + count <= self.data.length else { return nil }
let subdata = self.data.subdata(with: NSRange(location: self.index, length: count))
self.index += count
return subdata as NSData?
}
func upTo(_ marker:UInt8) -> NSData? {
if let end = (self.index..<self.data.length).index( where: { self.data.base64EncodedData()[$0] == marker } ) {
let upTo = self.next(end - self.index)
self.skip() // consume the marker
return upTo
}
else {
return nil
}
}
func skip(_ count:Int = 1) {
self.index += count
}
func skipThrough(_ marker:UInt8) {
if let end = (self.index..<self.data.length).index( where: { self.data.base64EncodedData()[$0] == marker } ) {
self.index = end + 1
}
else {
self.index = self.data.length
}
}
}
使用这个DataStream类和几个NSData方法,我能够模仿java方法DataInputStream.ReadInt()的行为:
var someID : Int = 0
//get the part of the data that represents someID
guard let someIDData = dataStream.next(4 /*size of someID in the data*/) else { fatalError("Error getting someID bytes")}
//convert the data bytes to an Int
someIDData.getBytes(&someID, length: someIDData.length)
如果有人有更好的方法来实现这一点,我很乐意听到!我是Swift的新手,所以这可能不是最好的方式。这适用于Swift 3.1。