unit SendMsgSock;

interface

uses Windows, Messages, SysUtils, Mpeg1DataFormat, Classes, MyDef, WinSock;

procedure SendMpegHeadMark(const iMulticastGroup: integer {組播組序號});
procedure SendMsg_Refresh(const iMulticastGroup: integer {組播組序號});
procedure SendMsg_Stop(const iMulticastGroup: integer {組播組序號});
//procedure MySendMsgChar(const MsgChar:Char);

implementation

procedure MySendMsgChar(const MsgChar: Char; const iMulticastGroup: integer {組播組序號});
var
  addr_to: sockaddr_in;
  FSocket: TSocket;
  mreq: ip_mreq;
  VideoParkFrame: array[1..VideoPackSize] of byte;
  PlayBuf, SendPackbuf: PByte;
begin
  FSocket := Socket(AF_INET, SOCK_DGRAM, 0); //初始化socket
  if FSocket = SOCKET_ERROR then MessageBox(0, 'Socket() Failed', MpgServerName, MB_ICONERROR);
  mreq.imr_multiaddr.S_addr := inet_addr(TMulticastIp[iMulticastGroup]); //htonl(INADDR_ALLHOSTS_GROUP);
  mreq.imr_interface.S_addr := htonl(INADDR_ANY);
  if setsockopt(FSocket, IPPROTO_IP, IP_ADD_MEMBERSHIP, pchar(@mreq), sizeof(mreq)) = SOCKET_ERROR then
  begin
    MessageBox(0, '無法進行UDP組播', '', 0);
  end;
     //綁定要發送的Udp包的socketaddr_in結構
  ZeroMemory(@addr_to, sizeof(sockaddr_in));
  addr_to.sin_family := AF_INET;
  addr_to.sin_port := htons(TMulticastPort[iMulticastGroup]);
  addr_to.sin_addr.S_addr := inet_addr(TMulticastIp[iMulticastGroup]); //INADDR_BROADCAST;

  VideoParkFrame[1] := byte('C');
  VideoParkFrame[2] := byte('J');
  VideoParkFrame[3] := byte('T');
  VideoParkFrame[4] := byte(MsgChar);

  PlayBuf := GetMemory(MpegFrameSize); //分配讀文件塊要保存的內存
  ZeroMemory(PlayBuf, MpegFrameSize);
  SendPackbuf := GetMemory(VideoPackSize); //分配向網絡發包的內存
  ZeroMemory(SendPackbuf, VideoPackSize);
//Move(PlayBuf^,VideoParkFrame[5],MpegFrameSize); //效率比CopyMemory高,但是占用Cpu
//Move(VideoParkFrame,SendPackbuf^,VideoPackSize);
  CopyMemory(@VideoParkFrame[5], PlayBuf, MpegFrameSize);
  CopyMemory(SendPackbuf, @VideoParkFrame, VideoPackSize);
  Sendto(FSocket, SendPackbuf^, VideoPackSize, 0, addr_to, sizeof(addr_to));
  Sleep(8);
   //釋放內存
  if PlayBuf <> nil then FreeMemory(PlayBuf);
  if SendPackbuf <> nil then FreeMemory(SendPackbuf);
//關閉Socket句柄
  setsockopt(FSocket, IPPROTO_IP, IP_DROP_MEMBERSHIP, pchar(@mreq), sizeof(mreq)); //離開組播組
  if FSocket <> Invalid_SOCKET then CloseSocket(FSocket);
end;

procedure SendMpegHeadMark(const iMulticastGroup: integer {組播組序號});
begin
  MySendMsgChar('A', iMulticastGroup);
end;

procedure SendMsg_Refresh(const iMulticastGroup: integer {組播組序號});
begin
  MySendMsgChar('R', iMulticastGroup);
end;

procedure SendMsg_Stop(const iMulticastGroup: integer {組播組序號});
begin
  MySendMsgChar('E', iMulticastGroup);
end;
var
  Re: integer;
  Wsa: TWSAData;
initialization
  Re := WSAStartup($101, Wsa); //初始化Wsock32.dll,MakeWord(2,2),
  if Re <> 0 then MessageBox(0, 'WSAStartup Failed', MpgServerName, MB_ICONERROR);
finalization
  WSACleanup; //結束對WSocket32.dll調用
end.