Method DirectRead

Libraries/unrar/file.cpp:409–472

Returns -1 in case of error.

// Returns -1 in case of error.
int File::DirectRead(void *Data,size_t Size)
{
#ifdef _WIN_ALL
  const size_t MaxDeviceRead=20000;
  const size_t MaxLockedRead=32768;
#endif
  if (HandleType==FILE_HANDLESTD)
  {
#ifdef _WIN_ALL
//    if (Size>MaxDeviceRead)
//      Size=MaxDeviceRead;
    hFile=GetStdHandle(STD_INPUT_HANDLE);
#else
#ifdef FILE_USE_OPEN
    hFile=STDIN_FILENO;
#else
    hFile=stdin;
#endif
#endif
  }
#ifdef _WIN_ALL
  // For pipes like 'type file.txt | rar -si arcname' ReadFile may return
  // data in small ~4KB blocks. It may slightly reduce the compression ratio.
  DWORD Read;
  if (!ReadFile(hFile,Data,(DWORD)Size,&Read,NULL))
  {
    if (IsDevice() && Size>MaxDeviceRead)
      return DirectRead(Data,MaxDeviceRead);
    if (HandleType==FILE_HANDLESTD && GetLastError()==ERROR_BROKEN_PIPE)
      return 0;

    // We had a bug report about failure to archive 1C database lock file
    // 1Cv8tmp.1CL, which is a zero length file with a region above 200 KB
    // permanently locked. If our first read request uses too large buffer
    // and if we are in -dh mode, so we were able to open the file,
    // we'll fail with "Read error". So now we use try a smaller buffer size
    // in case of lock error.
    if (HandleType==FILE_HANDLENORMAL && Size>MaxLockedRead &&
        GetLastError()==ERROR_LOCK_VIOLATION)
      return DirectRead(Data,MaxLockedRead);

    return -1;
  }
  return Read;
#else
#ifdef FILE_USE_OPEN
  ssize_t ReadSize=read(hFile,Data,Size);
  if (ReadSize==-1)
    return -1;
  return (int)ReadSize;
#else
  if (LastWrite)
  {
    fflush(hFile);
    LastWrite=false;
  }
  clearerr(hFile);
  size_t ReadSize=fread(Data,1,Size,hFile);