如何将记录从主机转换成网络字节顺序（大端）？ [英] How to convert a record from host to network byte order (big endian)?

问题描述

我有一个记录：

  Tconnecting = record 
 var 
 a：int64; 
 b：整数; 
 c：整数; 
结束
  

我需要使用UDP协议发送到服务器

我填写

  packet.a：= StrToInt64（'0x1234567890'）; 
 packet.b：= 0; 
 packet.c：= RandomRange（1，9999999）; 
  

并发送

  SetLength（send_data，sizeof（packet））; 
 send_data：= RawToBytes（packet，SizeOf（packet））; 
 udp.SendBuffer（make_it_big_endian（send_data））; <  - 问题...网络字节顺序
  

或者我正在做某事错误？我需要发送bign endian数据包

  pack（N *，int64，int，int）; （这是PHP）
  

谢谢。

包的各个字节反转，例如，在您的使用条款中包含FMX.Types单元：

 键入
 Tconnecting = record 
a ：int64; 
 b：整数; 
 c：整数; 
结束
 
 procedure TForm1.Button1Click（Sender：TObject）; 
 var 
数据包，BEPacket：Tconnecting; 
 begin 
 packet.a：= $ 0102030405060708; 
 packet.b：= $ 01020304; 
 packet.c：= $ 05060708; 
 // big endian packet 
 BEPacket：= Packet; 
 
 ReverseBytes（@ BEPacket.a，SizeOf（BePacket.a））; 
 ReverseBytes（@ BEPacket.b，SizeOf（BePacket.b））; 
 ReverseBytes（@ BEPacket.c，SizeOf（BePacket.c））; 
 
 Memo1.Lines.Add（Format（'a：％16.16x =>％16.16x'，[Packet.a，BEPacket.a]））; 
 Memo1.Lines.Add（格式（'b：％8.8x =>％8.8x'，[Packet.b，BEPacket.b]））; 
 Memo1.Lines.Add（Format（'c：％8.8x =>％8.8x'，[Packet.c，BEPacket.c]））; 
结束
  

I have a record:

  Tconnecting = record
  var
    a: int64;
    b: integer;
    c: integer;
  end;

which I need send to server using UDP protocol

I fill it

  packet.a := StrToInt64('0x1234567890');
  packet.b := 0;
  packet.c := RandomRange(1, 9999999);

and sending it

  SetLength(send_data, sizeof(packet));
  send_data := RawToBytes(packet, SizeOf(packet));
  udp.SendBuffer(make_it_big_endian(send_data)); <-- the question... "network byte order"

or maybe I'm doing something wrong? I need to send "bign endian" packet

pack("N*", int64, int, int); (this is in PHP)

Thanks.

解决方案

Assuming your code is running in a little-endian OS/Machine (like Windows/Intel), you can just reverse the individual bytes of your packet, for example, include the FMX.Types unit in your uses clause:

type
  Tconnecting = record
    a: int64;
    b: integer;
    c: integer;
  end;

procedure TForm1.Button1Click(Sender: TObject);
var
  Packet, BEPacket: Tconnecting;
begin
  packet.a := $0102030405060708;
  packet.b := $01020304;
  packet.c := $05060708;
  //big endian packet  
  BEPacket := Packet;

  ReverseBytes(@BEPacket.a, SizeOf(BePacket.a));
  ReverseBytes(@BEPacket.b, SizeOf(BePacket.b));
  ReverseBytes(@BEPacket.c, SizeOf(BePacket.c));

  Memo1.Lines.Add(Format('a: %16.16x => %16.16x', [Packet.a, BEPacket.a]));
  Memo1.Lines.Add(Format('b: %8.8x => %8.8x', [Packet.b, BEPacket.b]));
  Memo1.Lines.Add(Format('c: %8.8x => %8.8x', [Packet.c, BEPacket.c]));
end;

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