uefilib.c

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  the released state, and restores the system’s task priority level to its 
  previous level.

  @param  Lock  A pointer to the lock to release.

**/
VOID
EFIAPI
GlueEfiReleaseLock (
  IN EFI_LOCK  *Lock
  )
{
  EFI_TPL Tpl;

  ASSERT (Lock != NULL);
  ASSERT (Lock->Lock == EfiLockAcquired);

  Tpl = Lock->OwnerTpl;
  
  Lock->Lock = EfiLockReleased;

  gBS->RestoreTPL (Tpl);
}

/**
  This function looks up a Unicode string in UnicodeStringTable.  If Language is 
  a member of SupportedLanguages and a Unicode string is found in UnicodeStringTable
  that matches the language code specified by Language, then it is returned in 
  UnicodeString.

  @param  Language                A pointer to the ISO 639-2 language code for the 
                                  Unicode string to look up and return.
  @param  SupportedLanguages      A pointer to the set of ISO 639-2 language codes 
                                  that the Unicode string table supports.  Language 
                                  must be a member of this set.
  @param  UnicodeStringTable      A pointer to the table of Unicode strings.
  @param  UnicodeString           A pointer to the Unicode string from UnicodeStringTable
                                  that matches the language specified by Language.

  @retval  EFI_SUCCESS            The Unicode string that matches the language 
                                  specified by Language was found
                                  in the table of Unicoide strings UnicodeStringTable, 
                                  and it was returned in UnicodeString.
  @retval  EFI_INVALID_PARAMETER  Language is NULL.
  @retval  EFI_INVALID_PARAMETER  UnicodeString is NULL.
  @retval  EFI_UNSUPPORTED        SupportedLanguages is NULL.
  @retval  EFI_UNSUPPORTED        UnicodeStringTable is NULL.
  @retval  EFI_UNSUPPORTED        The language specified by Language is not a 
                                  member of SupportedLanguages.
  @retval  EFI_UNSUPPORTED        The language specified by Language is not 
                                  supported by UnicodeStringTable.

**/
EFI_STATUS
EFIAPI
LookupUnicodeString (
  IN CONST CHAR8                     *Language,
  IN CONST CHAR8                     *SupportedLanguages,
  IN CONST EFI_UNICODE_STRING_TABLE  *UnicodeStringTable,
  OUT CHAR16                         **UnicodeString
  )
{
  //
  // Make sure the parameters are valid
  //
  if (Language == NULL || UnicodeString == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // If there are no supported languages, or the Unicode String Table is empty, then the
  // Unicode String specified by Language is not supported by this Unicode String Table
  //
  if (SupportedLanguages == NULL || UnicodeStringTable == NULL) {
    return EFI_UNSUPPORTED;
  }

  //
  // Make sure Language is in the set of Supported Languages
  //
  while (*SupportedLanguages != 0) {
    if (CompareIso639LanguageCode (Language, SupportedLanguages)) {

      //
      // Search the Unicode String Table for the matching Language specifier
      //
      while (UnicodeStringTable->Language != NULL) {
        if (CompareIso639LanguageCode (Language, UnicodeStringTable->Language)) {

          //
          // A matching string was found, so return it
          //
          *UnicodeString = UnicodeStringTable->UnicodeString;
          return EFI_SUCCESS;
        }

        UnicodeStringTable++;
      }

      return EFI_UNSUPPORTED;
    }

    SupportedLanguages += 3;
  }

  return EFI_UNSUPPORTED;
}

/**
  This function adds a Unicode string to UnicodeStringTable.
  If Language is a member of SupportedLanguages then UnicodeString is added to 
  UnicodeStringTable.  New buffers are allocated for both Language and 
  UnicodeString.  The contents of Language and UnicodeString are copied into 
  these new buffers.  These buffers are automatically freed when 
  FreeUnicodeStringTable() is called.

  @param  Language                A pointer to the ISO 639-2 language code for the Unicode 
                                  string to add.
  @param  SupportedLanguages      A pointer to the set of ISO 639-2 language codes
                                  that the Unicode string table supports.
                                  Language must be a member of this set.
  @param  UnicodeStringTable      A pointer to the table of Unicode strings.
  @param  UnicodeString           A pointer to the Unicode string to add.

  @retval EFI_SUCCESS             The Unicode string that matches the language 
                                  specified by Language was found in the table of 
                                  Unicode strings UnicodeStringTable, and it was 
                                  returned in UnicodeString.
  @retval EFI_INVALID_PARAMETER   Language is NULL.
  @retval EFI_INVALID_PARAMETER   UnicodeString is NULL.
  @retval EFI_INVALID_PARAMETER   UnicodeString is an empty string.
  @retval EFI_UNSUPPORTED         SupportedLanguages is NULL.
  @retval EFI_ALREADY_STARTED     A Unicode string with language Language is 
                                  already present in UnicodeStringTable.
  @retval EFI_OUT_OF_RESOURCES    There is not enough memory to add another 
                                  Unicode string to UnicodeStringTable.
  @retval EFI_UNSUPPORTED         The language specified by Language is not a 
                                  member of SupportedLanguages.

**/
EFI_STATUS
EFIAPI
AddUnicodeString (
  IN CONST CHAR8               *Language,
  IN CONST CHAR8               *SupportedLanguages,
  IN EFI_UNICODE_STRING_TABLE  **UnicodeStringTable,
  IN CONST CHAR16              *UnicodeString
  )
{
  UINTN                     NumberOfEntries;
  EFI_UNICODE_STRING_TABLE  *OldUnicodeStringTable;
  EFI_UNICODE_STRING_TABLE  *NewUnicodeStringTable;
  UINTN                     UnicodeStringLength;

  //
  // Make sure the parameter are valid
  //
  if (Language == NULL || UnicodeString == NULL || UnicodeStringTable == NULL) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // If there are no supported languages, then a Unicode String can not be added
  //
  if (SupportedLanguages == NULL) {
    return EFI_UNSUPPORTED;
  }

  //
  // If the Unicode String is empty, then a Unicode String can not be added
  //
  if (UnicodeString[0] == 0) {
    return EFI_INVALID_PARAMETER;
  }

  //
  // Make sure Language is a member of SupportedLanguages
  //
  while (*SupportedLanguages != 0) {
    if (CompareIso639LanguageCode (Language, SupportedLanguages)) {

      //
      // Determine the size of the Unicode String Table by looking for a NULL Language entry
      //
      NumberOfEntries = 0;
      if (*UnicodeStringTable != NULL) {
        OldUnicodeStringTable = *UnicodeStringTable;
        while (OldUnicodeStringTable->Language != NULL) {
          if (CompareIso639LanguageCode (Language, OldUnicodeStringTable->Language)) {
            return EFI_ALREADY_STARTED;
          }

          OldUnicodeStringTable++;
          NumberOfEntries++;
        }
      }

      //
      // Allocate space for a new Unicode String Table.  It must hold the current number of
      // entries, plus 1 entry for the new Unicode String, plus 1 entry for the end of table
      // marker
      //
      NewUnicodeStringTable = AllocatePool ((NumberOfEntries + 2) * sizeof (EFI_UNICODE_STRING_TABLE));
      if (NewUnicodeStringTable == NULL) {
        return EFI_OUT_OF_RESOURCES;
      }

      //
      // If the current Unicode String Table contains any entries, then copy them to the
      // newly allocated Unicode String Table.
      //
      if (*UnicodeStringTable != NULL) {
        CopyMem (
           NewUnicodeStringTable,
           *UnicodeStringTable,
           NumberOfEntries * sizeof (EFI_UNICODE_STRING_TABLE)
           );
      }

      //
      // Allocate space for a copy of the Language specifier
      //
      NewUnicodeStringTable[NumberOfEntries].Language = AllocateCopyPool (3, Language);
      if (NewUnicodeStringTable[NumberOfEntries].Language == NULL) {
        (gBS->FreePool) (NewUnicodeStringTable);
        return EFI_OUT_OF_RESOURCES;
      }

      //
      // Compute the length of the Unicode String
      //
      for (UnicodeStringLength = 0; UnicodeString[UnicodeStringLength] != 0; UnicodeStringLength++)
        ;

      //
      // Allocate space for a copy of the Unicode String
      //
      NewUnicodeStringTable[NumberOfEntries].UnicodeString = AllocateCopyPool (
                                                              (UnicodeStringLength + 1) * sizeof (CHAR16),
                                                              UnicodeString
                                                              );
      if (NewUnicodeStringTable[NumberOfEntries].UnicodeString == NULL) {
        (gBS->FreePool) (NewUnicodeStringTable[NumberOfEntries].Language);
        (gBS->FreePool) (NewUnicodeStringTable);
        return EFI_OUT_OF_RESOURCES;
      }

      //
      // Mark the end of the Unicode String Table
      //
      NewUnicodeStringTable[NumberOfEntries + 1].Language       = NULL;
      NewUnicodeStringTable[NumberOfEntries + 1].UnicodeString  = NULL;

      //
      // Free the old Unicode String Table
      //
      if (*UnicodeStringTable != NULL) {
        (gBS->FreePool) (*UnicodeStringTable);
      }

      //
      // Point UnicodeStringTable at the newly allocated Unicode String Table
      //
      *UnicodeStringTable = NewUnicodeStringTable;

      return EFI_SUCCESS;
    }

    SupportedLanguages += 3;
  }

  return EFI_UNSUPPORTED;
}

/**
  This function frees the table of Unicode strings in UnicodeStringTable.
  If UnicodeStringTable is NULL, then EFI_SUCCESS is returned.
  Otherwise, each language code, and each Unicode string in the Unicode string 
  table are freed, and EFI_SUCCESS is returned.

  @param  UnicodeStringTable  A pointer to the table of Unicode strings.

  @retval EFI_SUCCESS         The Unicode string table was freed.

**/
EFI_STATUS
EFIAPI
FreeUnicodeStringTable (
  IN EFI_UNICODE_STRING_TABLE  *UnicodeStringTable
  )
{
  UINTN Index;

  //
  // If the Unicode String Table is NULL, then it is already freed
  //
  if (UnicodeStringTable == NULL) {
    return EFI_SUCCESS;
  }

  //
  // Loop through the Unicode String Table until we reach the end of table marker
  //
  for (Index = 0; UnicodeStringTable[Index].Language != NULL; Index++) {

    //
    // Free the Language string from the Unicode String Table
    //
    (gBS->FreePool) (UnicodeStringTable[Index].Language);

    //
    // Free the Unicode String from the Unicode String Table
    //
    if (UnicodeStringTable[Index].UnicodeString != NULL) {
      (gBS->FreePool) (UnicodeStringTable[Index].UnicodeString);
    }
  }

  //
  // Free the Unicode String Table itself
  //
  (gBS->FreePool) (UnicodeStringTable);

  return EFI_SUCCESS;
}