Swift3 Swift 3.1中数据字节到sockaddr的转换

我正在将

数据字节

转换为

sockaddr

以获取

sa_family\t

在

ObjC

中，如下所示：

NSData *     hostAddress;
- (sa_family_t)hostAddressFamily {
    sa_family_t     result;

    result = AF_UNSPEC;
    if ( (self.hostAddress != nil) && (self.hostAddress.length >= sizeof(struct sockaddr)) ) {
        result = ((const struct sockaddr *) self.hostAddress.bytes)->sa_family;
    }
    return result;
}

var hostAddress:Data?

 private func hostAddressFamily() -> sa_family_t{

        var result: sa_family_t = sa_family_t(AF_UNSPEC)
        if (hostAddress != nil) && ((hostAddress?.count ?? 0) >= MemoryLayout<sockaddr>.size) {

            // Generic parameter 'ContentType' could not be inferred
            self.hostAddress!.withUnsafeBytes({ bytes in
                bytes.withMemoryRebound(to: sockaddr.self, capacity: 1, {sockBytes in
                    result = sockBytes.pointee.sa_family
                })
            })
        }

        return result
    }

在swift中，我尝试将其转换为以下内容：

NSData *     hostAddress;
- (sa_family_t)hostAddressFamily {
    sa_family_t     result;

    result = AF_UNSPEC;
    if ( (self.hostAddress != nil) && (self.hostAddress.length >= sizeof(struct sockaddr)) ) {
        result = ((const struct sockaddr *) self.hostAddress.bytes)->sa_family;
    }
    return result;
}

var hostAddress:Data?

 private func hostAddressFamily() -> sa_family_t{

        var result: sa_family_t = sa_family_t(AF_UNSPEC)
        if (hostAddress != nil) && ((hostAddress?.count ?? 0) >= MemoryLayout<sockaddr>.size) {

            // Generic parameter 'ContentType' could not be inferred
            self.hostAddress!.withUnsafeBytes({ bytes in
                bytes.withMemoryRebound(to: sockaddr.self, capacity: 1, {sockBytes in
                    result = sockBytes.pointee.sa_family
                })
            })
        }

        return result
    }

var主机地址：数据？
private func hostAddressFamily（）->sau family\t{
var结果：sa_family_t=sa_family_t（AF_Unsec）
如果（主机地址！=nil）&（（主机地址？.count±0）>=MemoryLayout.size）{
//无法推断泛型参数“ContentType”
self.hostAddress！.withUnsafeBytes（{bytes in.）
withMemoryRebound（to:sockaddr.self，容量：1，{sockBytes in
结果=sockBytes.pointee.sa_族
})
})
}
返回结果
}

---

获取错误：无法推断泛型参数“ContentType”

查看

数据的签名。WithUnsafebyTestType

：

func withUnsafeBytes<ResultType, ContentType>(_ body: (Swift.UnsafePointer<ContentType>) throws -> ResultType) rethrows -> ResultType

此外，您不太可能需要绑定内存两次，因为

NSData

是非类型化的，并且您已经指定了要绑定到的类型

---

总而言之：

func hostAddressFamily() -> sa_family_t {

  var result = sa_family_t(AF_UNSPEC)

  guard
    let hostAddress = hostAddress,
    hostAddress.count >= MemoryLayout<sockaddr>.size
  else {
    return result
  }

  hostAddress.withUnsafeBytes { (_ bytes: UnsafePointer<sockaddr>) in
    result = bytes.pointee.sa_family
  }

  return result
}

func hostAddressFamily（）->sa_family\t{
var结果=sa_系列（AF_UNSPEC）
警卫
让hostAddress=hostAddress，
hostAddress.count>=MemoryLayout.size
否则{
返回结果
}
hostAddress.withUnsafeBytes{（bytes:UnsafePointer）位于
结果=bytes.pointee.sa_族
}
返回结果
}