Exemple #1
0
  static FT_ULong
  ft_lzw_file_io( FT_LZWFile  zip,
                  FT_ULong    pos,
                  FT_Byte*    buffer,
                  FT_ULong    count )
  {
    FT_ULong  result = 0;
    FT_Error  error;


    /* Teset inflate stream if we're seeking backwards.        */
    /* Yes, that is not too efficient, but it saves memory :-) */
    if ( pos < zip->pos )
    {
      error = ft_lzw_file_reset( zip );
      if ( error )
        goto Exit;
    }

    /* skip unwanted bytes */
    if ( pos > zip->pos )
    {
      error = ft_lzw_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) );
      if ( error )
        goto Exit;
    }

    if ( count == 0 )
      goto Exit;

    /* now read the data */
    for (;;)
    {
      FT_ULong  delta;


      delta = (FT_ULong)( zip->limit - zip->cursor );
      if ( delta >= count )
        delta = count;

      FT_MEM_COPY( buffer, zip->cursor, delta );
      buffer      += delta;
      result      += delta;
      zip->cursor += delta;
      zip->pos    += delta;

      count -= delta;
      if ( count == 0 )
        break;

      error = ft_lzw_file_fill_output( zip );
      if ( error )
        break;
    }

  Exit:
    return result;
  }
Exemple #2
0
  static FT_ULong
  ft_lzw_file_io( FT_LZWFile  zip,
                  FT_ULong    pos,
                  FT_Byte*    buffer,
                  FT_ULong    count )
  {
    FT_ULong  result = 0;
    FT_Error  error;


    /* seeking backwards. */
    if ( pos < zip->pos )
    {
      /* If the new position is within the output buffer, simply       */
      /* decrement pointers, otherwise we reset the stream completely! */
      if ( ( zip->pos - pos ) <= (FT_ULong)( zip->cursor - zip->buffer ) )
      {
        zip->cursor -= zip->pos - pos;
        zip->pos     = pos;
      }
      else
      {
        error = ft_lzw_file_reset( zip );
        if ( error )
          goto Exit;
      }
    }

    /* skip unwanted bytes */
    if ( pos > zip->pos )
    {
      error = ft_lzw_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) );
      if ( error )
        goto Exit;
    }

    if ( count == 0 )
      goto Exit;

    /* now read the data */
    for (;;)
    {
      FT_ULong  delta;


      delta = (FT_ULong)( zip->limit - zip->cursor );
      if ( delta >= count )
        delta = count;

      FT_MEM_COPY( buffer + result, zip->cursor, delta );
      result      += delta;
      zip->cursor += delta;
      zip->pos    += delta;

      count -= delta;
      if ( count == 0 )
        break;

      error = ft_lzw_file_fill_output( zip );
      if ( error )
        break;
    }

  Exit:
    return result;
  }