gif_lzw.c

ucOS 模拟环境

   else
	{
		ucGifParameter->uReInfor->ucVersion = VERSION89;
	}

  /* Read and decipher Logical Screen Descriptor */
 
	if( !readFromBuffer(7 , hdrbuf))
	{
      #ifdef PCVER
		   WriteToErrorFile("input_init",ERROR_LOGICAL_SCREEN_DESCRIPTOR,FileError);
      #endif
		InsertError(ERROR_LOGICAL_SCREEN_DESCRIPTOR);
		return FALSE;
	}
	
	*log_width = LM_to_uint(hdrbuf[0],hdrbuf[1]);
	*log_height = LM_to_uint(hdrbuf[2],hdrbuf[3]);
	ucGifParameter->uReInfor->usSorImageHigh = *log_height;
	ucGifParameter->uReInfor->usSorImageWidth = *log_width;
    colorResolution = hdrbuf[4] & 0x07;
	colormaplen = 2 << (colorResolution);
   if( (colorResolution + 1) > ucGifParameter->ucOutColorResolution )
   {
      cinfo->quantize_colors = TRUE;
   }
   else
   {
	   if(ucGifParameter->ucDitherMethod != GIF_NONE_DITHER)
			cinfo->quantize_colors = TRUE;
   }


	 /* Read global colormap if header indicates it is present */
	 /* we ignore the color resolution, sort flag, and background color index */
	aspectRatio = hdrbuf[6] & 0xFF;
	if (aspectRatio != 0 && aspectRatio != 49)
	{
      #ifdef PCVER
	      WriteToErrorFile("input_init",ERROR_NONSQUARE_PIXELS,FileError);
      #endif
	  InsertError(ERROR_NONSQUARE_PIXELS);
	}
	
	if (BitSet(hdrbuf[4], COLORMAPFLAG))
   {
		if(!ReadColorMap(cinfo, colormaplen, colormap))
      {
			InsertError(ERROR_READ_BYTE_ERROR);
			return FALSE;
      }
   }
   c = ReadByte();
   if((c != ';') && (c != '!') && (c != ','))
   {
      return FALSE;
   }
   SetBufferCur( GetDataBufferCur() - 1);
	if(ucGifParameter->ucGetFileHeader == TRUE)
	{
		//start calculate the count of picture 
		PictureCount = 0;
		for(;;)
		{
			
			c = ReadByte();
			if( (c !=';')&& (c!= '!') && (c != ','))
			{
				InsertError(ERROR_FILE_DATA_ERROR);
				return FALSE;
			}
			 if(c == EOF)
			{
				 return FALSE;
			}
			if (c == ';')
			{
				break;
			}
			if (c == '!') 
			{		/* Extension */
				c = ReadByte();
				if(c == COMMENT_EXTENSION)
				{
					if(ucGifParameter->ucCommentFlag != GIF_NO_COMMENT)
					{
						if(CommentCount == ucGifParameter->ucCommentFlag)
						{
							c = ReadByte();
							if(c == 0)
								continue;
							if (c > ucGifParameter->ulCommentBufLen  )
							{
								readFromBuffer(ucGifParameter->ulCommentBufLen ,ucGifParameter->uReInfor->ucCommentBuf);
								SetBufferCur(GetDataBufferCur() + c - ucGifParameter->ulCommentBufLen);
								ucGifParameter->uReInfor->ulCommentBufLen = ucGifParameter->ulCommentBufLen;
								SkipDataBlocks ();
							}
							else
							{
								ucGifParameter->uReInfor->ulCommentBufLen = c;
								readFromBuffer(c,ucGifParameter->uReInfor->ucCommentBuf);
								SkipDataBlocks ();
							//we only get the frist block of comment 
							}
						}
						else
						{
							CommentCount++;
							SkipDataBlocks ();
						}

					}else
					{
						SkipDataBlocks ();
					}
				}
				else
				{
					if(c == EOF)
					{
						return FALSE;
					}
					SkipDataBlocks();
				}
				continue;
			}
			if (c == ',') 
			{
				PictureCount++;
				if(! skipFrame())
				{
					return FALSE;
				}
			}

	    }
		ucGifParameter->uReInfor->ucImageSum = (uchar)PictureCount;
		return TRUE;
	}

	//start decide whether zoom 

	/* Scan until we reach start of desired image.
	* We don't currently support skipping images, but could add it easily.
	*/
	//image index in gif buffer
	
	playback = 	ucGifParameter->ucPlayback;
	if( playback < 0)
	{
      #ifdef PCVER
		   WriteToErrorFile("input_init",ERROR_IMAGE_NUMBER_ERROR,FileError);
      #endif
		InsertError(ERROR_IMAGE_NUMBER_ERROR);
		return FALSE;
	}
	PictureCount = 0;
	for (;;)
   {
      c = ReadByte();

	  if( (c !=';')&& (c!= '!') && (c != ','))
				return FALSE;
	   if(c == EOF)
		{
		   return FALSE;
		 }
	   if (c == ';')		/* GIF terminator?? */
	   {
         #ifdef PCVER
		      WriteToErrorFile("input_init",ERROR_IMAGE_NUMBER_FEW,FileError);
         #endif
		   InsertError(ERROR_IMAGE_NUMBER_FEW);
		   return FALSE;
	   }
      if (c == '!')
      {		/* Extension */
         if(!DoExtension(ucGifParameter))
         {
			 InsertError(ERROR_READ_BYTE_ERROR);
		      return FALSE;
         }
         continue;
      }
   	if (c != ',')
      {		/* Not an image separator? */
       continue;
      }
      else
	   {
		   if( PictureCount != playback )
		   {
			   //readFromBuffer( 9,hdrbuf );
			   if(!skipFrame())
            {
				  InsertError(ERROR_READ_BYTE_ERROR);
				   return FALSE;
            }
			   PictureCount ++;
			   continue;	
		   }
		   //else start decode the image//
	   }
	   /* Read and decipher Local Image Descriptor */
      if (! readFromBuffer( 9,hdrbuf ))
	   {
		   InsertError(ERROR_LOCAL_IMAGE_DESCRIPTOR);
         #ifdef PCVER
		      WriteToErrorFile("input_init",ERROR_LOCAL_IMAGE_DESCRIPTOR,FileError);
         #endif
     	   return FALSE;
	   }
      /* we ignore top/left position info, also sort flag */
      *width = LM_to_uint(hdrbuf[4],hdrbuf[5]);
	  *height = LM_to_uint(hdrbuf[6],hdrbuf[7]);
	  if((*width > MAXWIDTH)||(*height > MAXHEIGHT))
	  {
		   InsertError(ERROR_SIZE_OVERTOP);
         #ifdef PCVER
		      WriteToErrorFile("input_init",ERROR_SIZE_OVERTOP,FileError);
         #endif
     	   return FALSE;

	  }
	   ucGifParameter->uReInfor->usXPOS = LM_to_uint( hdrbuf[0], hdrbuf[1] );
	   ucGifParameter->uReInfor->usYPOS = LM_to_uint( hdrbuf[2], hdrbuf[3] );
	   ZoomSize = ucGifParameter->ucScale & 0xffff;
	   if( *g_ZoomType == IMAGE_GEOMETRY_NO_INTERPOLATE )
	   {
		   if((ZoomSize & 0xff )!= ((ZoomSize & 0xff00)>> 8))
		   {
			   *zoomflag  = TRUE;
			   memset(width_record, 0, 4096);
			   memset(height_record,0 , 4096);
           
			switch(((ZoomSize & 0xff00)>> 8))
			{
			case 1:
				scale_width = *width;
				scale_height = *height;
				break;
			case 2:
				scale_width =(*width)/2;
				scale_height = (*height)/2 ;
				ucGifParameter->uReInfor->usXPOS = (ucGifParameter->uReInfor->usXPOS)/2;
				ucGifParameter->uReInfor->usYPOS = (ucGifParameter->uReInfor->usYPOS)/2;
				break;
			case 4:
				scale_width =(*width)/4;
				scale_height = (*height)/4 ;
				ucGifParameter->uReInfor->usXPOS = ucGifParameter->uReInfor->usXPOS/4;
				ucGifParameter->uReInfor->usYPOS = ucGifParameter->uReInfor->usYPOS/4;
				break;
			case 8:
				scale_width =(*width)/8;
				scale_height = (*height)/8 ;
				ucGifParameter->uReInfor->usXPOS = ucGifParameter->uReInfor->usXPOS/8;
				ucGifParameter->uReInfor->usYPOS = ucGifParameter->uReInfor->usYPOS/8;
				break;

			case 16:
				scale_width =(*width)/16;
				scale_height = (*height)/16 ;
				ucGifParameter->uReInfor->usXPOS = ucGifParameter->uReInfor->usXPOS/16;
				ucGifParameter->uReInfor->usYPOS = ucGifParameter->uReInfor->usYPOS/16;
				break;
			case 32:
				scale_width =(*width)/32;
				scale_height = (*height)/32 ;
				ucGifParameter->uReInfor->usXPOS = ucGifParameter->uReInfor->usXPOS/32;
				ucGifParameter->uReInfor->usYPOS = ucGifParameter->uReInfor->usYPOS/32;
				break;
			default:
				scale_width = *width;
				scale_height = *height;
				break;
			}
			StrechPixels((*width), scale_width , width_record);
			StrechPixels((*height), scale_height , height_record);
			cinfo->image_height =	scale_height;
			cinfo->image_width =	scale_width;
			cinfo->output_height =	scale_height;
			cinfo->output_width =	scale_width;

		
		}
		else
		{
			cinfo->image_height = *height;
			cinfo->image_width = *width;
			cinfo->output_height = *height;
			cinfo->output_width = *width;
		}
	}else
	{
		cinfo->image_height = *height;
		cinfo->image_width = *width;
		cinfo->output_height = *height;
		cinfo->output_width = *width;
	}
	if( (cinfo->image_height == 0 ) ||( cinfo->image_width == 0))
	{
		 InsertError( ERROR_ZOOM_OVERTOP );

         #ifdef PCVER
		      WriteToErrorFile("input_init",ERROR_ZOOM_OVERTOP, FileError);
         #endif

		return FALSE;
	}
	
   *is_interlaced = BitSet(hdrbuf[8], INTERLACE);
	/* Read local colormap if header indicates it is present */
    /* Note: if we wanted to support skipping images, */
    /* we'd need to skip rather than read colormap for ignored images */
   if (BitSet(hdrbuf[8], COLORMAPFLAG))
	{
      colormaplen = 2 << (hdrbuf[8] & 0x07);
      if(!ReadColorMap(cinfo, colormaplen, colormap))
      {
		  InsertError(ERROR_READ_BYTE_ERROR);
		  return FALSE;
      }
   }
	*input_code_size = ReadByte(); /* get minimum-code-size byte */
   if (*input_code_size < 2 || *input_code_size >= MAX_LZW_BITS)
	{
		InsertError( ERROR_BOGUS_CODE_SIZE );
      #ifdef PCVER
		   WriteToErrorFile("input_init",ERROR_BOGUS_CODE_SIZE,FileError);
      #endif
		return FALSE;
	}
	/* Reached desired image, so break out of loop */
    /* If we wanted to skip this image, */
    /* we'd call SkipDataBlocks and then continue the loop */
    break;
	}
	ucGifParameter->uReInfor->ucSorColorResolution = TWENTY_FOUR_BIT_COLOR;
	ucGifParameter->uReInfor->ulDataOutBufLen = NUMCOLORS * cinfo->image_height * cinfo->image_width;
	InitLZWCode();
 	return TRUE;
}
//only for test//
#ifdef PCVER
   void  openErrorFile()
	{
		FileError = fopen("c:\\error.bin","wb");
	}
	void  WriteToErrorFile(const char* ErrorFunc,ulong ErrorCode,  FILE* f)
	{
		fwrite((uchar*)(&ErrorCode),1, 4,f);
	}
	void  closeFile()
	{
		fclose(FileError);
	}

#endif
//
#endif /* GIF_SUPPORTED */