(EFI_STRING Request)Construct using routing information GUID/NAME/PATH.

/*The source code is from EFI Dev Kit(EDk).*/
/*It will make a string. and its layout as below:*/

Word(2bytes)	Length	Description
0	5 Words(10 Bytes)	“GUID=”
5	16 Words(32 Bytes)	EFI_GUID
21	6 Words(12 Bytes)	“&NAME=”
27	00 + “??”=2Words x L1(L1 x 4 = 4L1 Bytes)	00??, 00??, 00??.....
27 + 2L1	6 Words(12 Bytes)	“&PATH=”
33 + 2L1	Word(2 bytes) x L2 = 2L2bytes	Device Path Size
(33 + 2L1 + L2)Last Word	1 Words(2 Bytes)	00

CHAR16 *
ConstructConfigHdr (
  IN EFI_GUID                *Guid,
  IN CHAR16                  *Name,
  IN EFI_HANDLE              DriverHandle
  )
/*++

Routine Description:
  Construct using routing information GUID/NAME/PATH.

Arguments:
  Guid          - Routing information: GUID.
  Name          - Routing information: NAME.
  DriverHandle  - Driver handle which contains the routing information: PATH.

Returns:
  NULL  - Fails.
  Other - Pointer to configHdr string.

--*/
{
  EFI_STATUS                 Status;
  CHAR16                     *ConfigHdr;
  EFI_DEVICE_PATH_PROTOCOL   *DevicePath;
  CHAR16                     *String;
  CHAR16                     *UpperString;
  UINTN                      Index;
  UINT8                      *Buffer;
  UINTN                      DevicePathLength;
  UINTN                      NameLength;

  //
  // Get the device path from handle installed EFI HII Config Access protocol
  //
  Status = BS->HandleProtocol (
                 DriverHandle,
                 &gEfiDevicePathProtocolGuid,
                 (VOID **) &DevicePath
                 );
  if (EFI_ERROR (Status)) {
    return NULL;
  }

  DevicePathLength = DevicePathSize (DevicePath);
  NameLength = StrLen (Name);
  ConfigHdr = AllocateZeroPool ((5 + sizeof (EFI_GUID) * 2 + 6 + NameLength * 4 + 6 + DevicePathLength * 2 + 1) * sizeof (CHAR16));
  if (ConfigHdr == NULL) {
    return NULL;
  } 

  String = ConfigHdr;
  StrCpy (String, L"GUID=");
  String += StrLen (L"GUID=");

  //
  // Append Guid converted to 32
  //
  UpperString = String;
  for (Index = 0, Buffer = (UINT8 *)Guid; Index < sizeof (EFI_GUID); Index++) {
    String += SPrint (String, 0, L"%02x", *Buffer++);
  }
  *String = 0;
  StrLwr (UpperString);

  //
  // Append L"&NAME="
  //
  StrCpy (String, L"&NAME=");
  String += StrLen (L"&NAME=");
  UpperString = String;
  for (Index = 0; Index < NameLength ; Index++) {
    String += SPrint (String, 0, L"00%x", Name[Index]);
  }
  *String = 0;
  StrLwr (UpperString);
  
  //
  // Append L"&PATH="
  //
  StrCpy (String, L"&PATH=");
  String += StrLen (L"&PATH=");
  UpperString = String;
  for (Index = 0, Buffer = (UINT8 *) DevicePath; Index < DevicePathLength; Index++) {
    String += SPrint (String, 0, L"%02x", *Buffer++);
  }
  *String = 0;
  StrLwr (UpperString);

  return ConfigHdr;
}