type
far_jmp = packed record
  PuhsOp: byte;
  PushArg: pointer;
  RetOp: byte;
 end;

 OldCode = packed record
  One: dword;
  two: word;
 end;

var

 JmpZwq9: far_jmp;
 OldZwq9: OldCode;
 PtrZwq9: pointer;


function TrueInternetReadFileEx(hFile: HINTERNET;  lpBuffersOut: Pointer;
  dwFlags: DWORD; dwContext: DWORD): BOOL; stdcall;
var
 Written:Dword;
begin
WriteProcessMemory(INVALID_HANDLE_VALUE, PtrZwq9,@OldZwq9, SizeOf(OldCode), Written);
Result:= InternetReadFileEx(hFile,lpBuffersOut,dwFlags,dwContext);
WriteProcessMemory(INVALID_HANDLE_VALUE, PtrZwq9,@JmpZwq9, SizeOf(far_jmp), Written);
end;



function NewInternetReadFileEx(hFile: HINTERNET;  lpBuffersOut: Pointer;
  dwFlags: DWORD; dwContext: DWORD): BOOL; stdcall;
var
 Rec:PInternetBuffers;
 F:File of Byte;
begin;
Result:=TrueInternetReadFileEx(hFile,lpBuffersOut,dwFlags,dwContext);
Rec:=lpBuffersOut;


AssignFile(F,'c:\1.data');
Rewrite(F);
BlockWrite(F,Rec^.lpvBuffer,Rec^.dwBufferLength);
CLoseFile(F); 
end;


Procedure HookInternetReadFileEx;
var
 Written:DWord;
 Lib:Cardinal;
begin
Lib:=GetModuleHandle('wininet.dll');
if Lib=0 then
   Lib:=LoadLibrary('wininet.dll');

PtrZwq9  := GetProcAddress(Lib,'InternetReadFileExA');
ReadProcessMemory(INVALID_HANDLE_VALUE, PtrZwq9, @OldZwq9, SizeOf(OldCode), Written);
JmpZwq9.PuhsOp  := $68;
JmpZwq9.PushArg := @NewInternetReadFileEx;
JmpZwq9.RetOp   := $C3;
WriteProcessMemory(INVALID_HANDLE_VALUE, PtrZwq9, @JmpZwq9, SizeOf(far_jmp), Written);
end;