ttfile.c

神龙卡开发原代码

    }

    CUR_Frame.cursor = CUR_Frame.address;
    return error;
  }


/*******************************************************************
 *
 *  Function    :  TT_Forget_Frame
 *
 *  Description :  Releases a cached frame after reading.
 *
 *  Input  :  None
 *
 *  Output :  SUCCESS on success. FAILURE on error.
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Forget_Frame( FRAME_ARG )
  {
    if ( CUR_Frame.address == NULL )
      return TT_Err_Nested_Frame_Access;

    if ( CUR_Frame.size > FRAME_CACHE_SIZE )
      FREE( CUR_Frame.address );

    ZERO_Frame( CUR_Frame );

    return TT_Err_Ok;
  }


#else /* TT_CONFIG_OPTION_THREAD_SAFE */

  /*******************************************************************/
  /*******************************************************************/
  /*******************************************************************/
  /********                                                   ********/
  /********  R E E N T R A N T   I M P L E M E N T A T I O N  ********/
  /********                                                   ********/
  /*******************************************************************/
  /*******************************************************************/
  /*******************************************************************/

/* a simple macro to access the file component's data */
#define files  ( *((TFile_Component*)engine.file_component) )

#define CUR_Stream   STREAM2REC( stream )    /* re-entrant macros */
#define CUR_Frame    (*frame)

#define STREAM_VARS  stream,
#define STREAM_VAR   stream


/*******************************************************************
 *
 *  Function    :  TTFile_Init
 *
 *  Description :  Initializes the File component.
 *
 ******************************************************************/

  LOCAL_FUNC
  TT_Error  TTFile_Init( PEngine_Instance  engine )
  {
    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  TTFile_Done
 *
 *  Description :  Finalizes the File component.
 *
 ******************************************************************/

  LOCAL_FUNC
  TT_Error  TTFile_Done( PEngine_Instance  engine )
  {
    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  TT_Use_Stream
 *
 *  Description :  Duplicates a stream for a new usage.
 *
 *  Input  :  input_stream   source stream to duplicate
 *            copy           address of target duplicate stream
 *
 *  Output :  error code.
 *            The target stream is set to NULL in case of failure.
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Use_Stream( TT_Stream   input_stream,
                           TT_Stream*  copy )
  {
    PStream_Rec  rec = STREAM2REC( input_stream );

    return TT_Open_Stream( rec->name, copy );
  }


/*******************************************************************
 *
 *  Function    : TT_Done_Stream
 *
 *  Description : Releases a given stream.
 *
 *  Input  :  stream  target stream
 *
 *  Output :
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Done_Stream( TT_Stream*  stream )
  {
    return TT_Close_Stream( stream );
  }


/*******************************************************************
 *
 *  Function    :  TT_Access_Frame
 *
 *  Description :  Notifies the component that we're going to read
 *                 'size' bytes from the current file position.
 *                 This function should load/cache/map these bytes
 *                 so that they will be addressed by the GET_xxx
 *                 functions easily.
 *
 *  Input  :  size   number of bytes to access.
 *
 *  Output :  SUCCESS on success. FAILURE on error.
 *
 *  Notes:    The function fails if the byte range is not within the
 *            the file, or if there is not enough memory to cache
 *            the bytes properly (which usually means that `size' is
 *            too big in both cases).
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Access_Frame( STREAM_ARGS FRAME_ARGS Long  size )
  {
    TT_Error  error;


    if ( CUR_Frame.address != NULL )
      return TT_Err_Nested_Frame_Access;

    if ( ALLOC( CUR_Frame.address, size ) )
      return error;
    CUR_Frame.size    = size;

    error = TT_Read_File( STREAM_VARS (void*)CUR_Frame.address, size );
    if ( error )
    {
      FREE( CUR_Frame.address );
      CUR_Frame.size    = 0;
    }

    CUR_Frame.cursor = CUR_Frame.address;
    return error;
  }


/*******************************************************************
 *
 *  Function    :  TT_Check_And_Access_Frame
 *
 *  Description :  Notifies the component that we're going to read
 *                 `size' bytes from the current file position.
 *                 This function should load/cache/map these bytes
 *                 so that they will be addressed by the GET_xxx
 *                 functions easily.
 *
 *  Input  :  size   number of bytes to access.
 *
 *  Output :  SUCCESS on success. FAILURE on error.
 *
 *  Notes:    The function truncates `size' if the byte range is not
 *            within the file.
 *
 *            It will fail if there is not enough memory to cache
 *            the bytes properly (which usually means that `size' is
 *            too big).
 *
 *            It will fail if you make two consecutive calls
 *            to TT_Access_Frame(), without a TT_Forget_Frame() between
 *            them.
 *
 *            The only difference with TT_Access_Frame() is that we
 *            check that the frame is within the current file.  We
 *            otherwise truncate it.
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Check_And_Access_Frame( STREAM_ARGS FRAME_ARGS Long  size )
  {
    TT_Error  error;
    Long      readBytes;


    if ( CUR_Frame.address != NULL )
      return TT_Err_Nested_Frame_Access;

    if ( ALLOC( CUR_Frame.address, size ) )
      return error;
    CUR_Frame.size    = size;

    readBytes = CUR_Stream->size - TT_File_Pos( STREAM_VAR );
    if ( size > readBytes )
      size = readBytes;

    error = TT_Read_File( STREAM_VARS (void*)CUR_Frame.address, size );
    if ( error )
    {
      FREE( CUR_Frame.address );
      CUR_Frame.size    = 0;
    }

    CUR_Frame.cursor = CUR_Frame.address;
    return error;
  }


/*******************************************************************
 *
 *  Function    :  TT_Forget_Frame
 *
 *  Description :  Releases a cached frame after reading.
 *
 *  Input  :  None
 *
 *  Output :  SUCCESS on success.  FAILURE on error.
 *
 ******************************************************************/

  EXPORT_FUNC
  TT_Error  TT_Forget_Frame( FRAME_ARG )
  {
    if ( CUR_Frame.address == NULL )
      return TT_Err_Nested_Frame_Access;

    FREE( CUR_Frame.address );
    ZERO_Frame( CUR_Frame );

    return TT_Err_Ok;
  }

#endif /* TT_CONFIG_OPTION_THREAD_SAFE */


  /*******************************************************************/
  /*******************************************************************/
  /*******************************************************************/
  /***********                                             ***********/
  /***********  C O M M O N   I M P L E M E N T A T I O N  ***********/
  /***********                                             ***********/
  /*******************************************************************/
  /*******************************************************************/
  /*******************************************************************/

/*******************************************************************
 *
 *  Function    :  Stream_Activate
 *
 *  Description :  activates a stream, this will either:
 *                   - open a new file handle if the stream is closed
 *                   - move the stream to the head of the linked list
 *
 *  Input  :  stream   the stream to activate
 *
 *  Output :  error condition.
 *
 *  Note   :  This function is also called with fresh new streams
 *            created by TT_Open_Stream().  They have their 'size'
 *            field set to -1.
 *
 ******************************************************************/

  static  TT_Error  Stream_Activate( PStream_Rec  stream )
  {
    if ( !stream->opened )
    {
      if ( (stream->file = fopen( (TT_Text*)stream->name, "rb" )) == 0 )
        return TT_Err_Could_Not_ReOpen_File;

      stream->opened = TRUE;

      /* A newly created stream has a size field of -1 */
      if ( stream->size < 0 )
      {
        fseek( stream->file, 0, SEEK_END );
        stream->size = ftell( stream->file );
        fseek( stream->file, 0, SEEK_SET );
      }

      /* Reset cursor in file */
      if ( stream->position )
      {
        if ( fseek( stream->file, stream->position, SEEK_SET ) != 0 )
        {
          /* error during seek */
          fclose( stream->file );
          stream->opened = FALSE;
          return TT_Err_Could_Not_ReSeek_File;
        }
      }
    }
    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  Stream_DeActivate
 *
 *  Description :  deactivates a stream, this will :
 *                   - close its file handle if it was opened
 *                   - remove it from the opened list if necessary
 *
 *  Input  :  stream   the stream to deactivate
 *
 *  Output :  Error condition
 *
 *  Note   :  the function is called whenever a stream is deleted
 *            (_not_ when a stream handle's is closed due to an
 *             activation). However, the stream record isn't
 *            destroyed by it..
 *
 ******************************************************************/

  static  TT_Error  Stream_Deactivate( PStream_Rec  stream )
  {
    if ( stream->opened )
    {
      /* Save its current position within the file */
      stream->position = ftell( stream->file );
      fclose( stream->file );
      stream->file   = 0;
      stream->opened = FALSE;
    }

    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  TT_Stream_Size
 *
 *  Description :  Returns the length of a given stream, even if it
 *                 is flushed.
 *
 *  Input  :  stream     the stream
 *
 *  Output :  Length of stream in bytes.
 *
 ******************************************************************/

  EXPORT_FUNC
  Long  TT_Stream_Size( TT_Stream  stream )
  {
    PStream_Rec  rec = STREAM2REC( stream );


    if ( rec )
      return rec->size;
    else
      return 0;  /* invalid stream - return 0 */
  }


/*******************************************************************
 *
 *  Function    :  TT_Open_Stream
 *
 *  Description :  Opens the font file and saves the total file size.
 *
 *  Input  :  error          address of stream's error variable
 *                           (re-entrant build only)