loadfile.c

frasr200的win 版本源码(18.21),使用make文件,使用的vc版本较低,在我的环境下编译有问题! 很不错的分形程序代码!

   EXIT_OVLY;
   return(0);
}


static int find_fractal_info(gif_file,info)
char *gif_file;
struct fractal_info *info;
{
   BYTE gifstart[18];
   char temp1[81];
   int scan_extend, block_type, block_len, data_len;
   int fractinf_len;
   int hdr_offset;

   if((fp = fopen(gif_file,"rb"))==NULL)
      return(-1);

   fread(gifstart,18,1,fp);
#ifndef XFRACT
   if (strncmp(gifstart,"GIF",3)!=0) { /* not GIF, maybe old .tga? */
#else
   if (strncmp((char *)gifstart,"GIF",3)!=0) { /* not GIF, maybe old .tga? */
#endif
      if(fread(info,FRACTAL_INFO_SIZE,1,fp)==1 &&
		 strncmp(info->info_id,"Fractal",8)==0) {
	 filetype = 1; /* Targa 16 */
	 GET16(gifstart[O_VSIZE],fileydots);
	 GET16(gifstart[O_HSIZE],filexdots);
	 filecolors = info->colors;
	 fileaspectratio = screenaspect;
	 if(fileydots == info->ydots && filexdots == info->xdots) {
	    fclose(fp);
	    return(0);
	    }
	 }
      fclose(fp);
      return(-1);
      }

   filetype = 0; /* GIF */
   GET16(gifstart[6],filexdots);
   GET16(gifstart[8],fileydots);
   filecolors = 2 << (gifstart[10] & 7);
   fileaspectratio = 0; /* unknown */
   if (gifstart[12]) { /* calc reasonably close value from gif header */
      fileaspectratio = (64.0 / ((double)(gifstart[12]) + 15.0))
		      * (double)fileydots / (double)filexdots;
      if ( fileaspectratio > screenaspect-0.03
	&& fileaspectratio < screenaspect+0.03)
	 fileaspectratio = screenaspect;
      }
   else
      if (fileydots * 4 == filexdots * 3) /* assume the common square pixels */
	 fileaspectratio = screenaspect;

   if (resume_info != NULL) { /* free the prior area if there is one */
      farmemfree(resume_info);
      resume_info = NULL;
      }
   if (rangeslen) { /* free prior ranges */
      farmemfree((char far *)ranges);
      rangeslen = 0;
      }

   /* Format of .gif extension blocks is:
	  1 byte    '!', extension block identifier
	  1 byte    extension block number, 255
	  1 byte    length of id, 11
	 11 bytes   alpha id, "fractintnnn" with fractint, nnn is secondary id
       n * {
	  1 byte    length of block info in bytes
	  x bytes   block info
	   }
	  1 byte    0, extension terminator
      To scan extension blocks, we first look in file at length of fractal_info
      (the main extension block) from end of file, looking for a literal known
      to be at start of our block info.  Then we scan forward a bit, in case
      the file is from an earlier fractint vsn with shorter fractal_info.
      If fractal_info is found and is from vsn>=14, it includes the total length
      of all extension blocks; we then scan them all first to last to load
      any optional ones which are present.
      Defined extension blocks:
	fractint001	header, always present
	fractint002	resume info for interrupted resumable image
	fractint003	additional formula type info
	fractint004	ranges info
   */

   memset(info,0,FRACTAL_INFO_SIZE);
   fractinf_len = FRACTAL_INFO_SIZE + (FRACTAL_INFO_SIZE+254)/255;
   fseek(fp,(long)(-1-fractinf_len),SEEK_END);
   fread(info,1,FRACTAL_INFO_SIZE,fp);
   if (strcmp(INFO_ID,info->info_id) == 0) {
#ifdef XFRACT
       decode_fractal_info(info,1);
#endif
      hdr_offset = -1-fractinf_len;
   } else {
      /* didn't work 1st try, maybe an older vsn, maybe junk at eof, scan: */
      int offset,i;
      char tmpbuf[110];
      hdr_offset = 0;
      offset = 80; /* don't even check last 80 bytes of file for id */
      while (offset < fractinf_len+513) { /* allow 512 garbage at eof */
	 offset += 100; /* go back 100 bytes at a time */
	 fseek(fp,(long)(0-offset),SEEK_END);
	 fread(tmpbuf,1,110,fp); /* read 10 extra for string compare */
	 for (i = 0; i < 100; ++i)
	    if (!strcmp(INFO_ID,&tmpbuf[i])) { /* found header? */
	       strcpy(info->info_id,INFO_ID);
	       fseek(fp,(long)(hdr_offset=i-offset),SEEK_END);
	       fread(info,1,FRACTAL_INFO_SIZE,fp);
#ifdef XFRACT
	       decode_fractal_info(info,1);
#endif
	       offset = 10000; /* force exit from outer loop */
	       break;
	       }
	 }
      }

   if (hdr_offset) { /* we found INFO_ID */

      if (info->version >= 4) {
	 /* first reload main extension block, reasons:
	      might be over 255 chars, and thus earlier load might be bad
	      find exact endpoint, so scan back to start of ext blks works
	    */
	 fseek(fp,(long)(hdr_offset-15),SEEK_END);
	 scan_extend = 1;
	 while (scan_extend) {
	    if (fgetc(fp) != '!' /* if not what we expect just give up */
	      || fread(temp1,1,13,fp) != 13
	      || strncmp(&temp1[2],"fractint",8))
	       break;
	    temp1[13] = 0;
	    block_type = atoi(&temp1[10]); /* e.g. "fractint002" */
	    switch (block_type) {
	       case 1: /* "fractint001", the main extension block */
		  if (scan_extend == 2) { /* we've been here before, done now */
		     scan_extend = 0;
		     break;
		     }
		  load_ext_blk((char far *)info,FRACTAL_INFO_SIZE);
#ifdef XFRACT
		  decode_fractal_info(info,1);
#endif
		  scan_extend = 2;
		  /* now we know total extension len, back up to first block */
		  fseek(fp,0L-info->tot_extend_len,SEEK_CUR);
		  break;
	       case 2: /* resume info */
		  skip_ext_blk(&block_len,&data_len); /* once to get lengths */
		  if ((resume_info = farmemalloc((long)data_len)) == NULL)
		     info->calc_status = 3; /* not resumable after all */
		  else {
		     fseek(fp,(long)(0-block_len),SEEK_CUR);
		     load_ext_blk(resume_info,data_len);
		     resume_len = data_len;
		     }
		  break;
	       case 3: /* formula info */
		  {
		  char *nameptr;
		  char tmpname[40];
		  load_ext_blk(tmpname,40);
		  switch (info->fractal_type) {
		     case LSYSTEM:
			nameptr = LName;
			break;
		     case IFS:
		     case IFS3D:
			nameptr = IFSName;
			break;
		     default:
			nameptr = FormName;
			break;
		     }
		  tmpname[ITEMNAMELEN] = 0;
		  strcpy(nameptr,tmpname);
		  /* perhaps in future add more here, check block_len for
		     backward compatibility */
		  }
		  break;
	       case 4: /* ranges info */
		  skip_ext_blk(&block_len,&data_len); /* once to get lengths */
		  if ((ranges = (int far *)farmemalloc((long)data_len))) {
		     fseek(fp,(long)(0-block_len),SEEK_CUR);
		     load_ext_blk((char far *)ranges,data_len);
		     rangeslen = data_len/2;
#ifdef XFRACTINT
		     fix_ranges(ranges,rangeslen,1);
#endif
		     }
		  break;
	       default:
		  skip_ext_blk(&block_len,&data_len);
	       }
	    }
	 }

      fclose(fp);
      fileaspectratio = screenaspect; /* if not >= v15, this is correct */
      return(0);
      }

   strcpy(info->info_id, "GIFFILE");
   info->iterations = 150;
   info->fractal_type = PLASMA;
   info->xmin = -1;
   info->xmax = 1;
   info->ymin = -1;
   info->ymax = 1;
   info->x3rd = -1;
   info->y3rd = -1;
   info->creal = 0;
   info->cimag = 0;
   info->videomodeax=255;
   info->videomodebx=255;
   info->videomodecx=255;
   info->videomodedx=255;
   info->dotmode = 0;
   info->xdots = filexdots;
   info->ydots = fileydots;
   info->colors = filecolors;
   info->version = 0; /* this forces lots more init at calling end too */

   /* zero means we won */
   fclose(fp);
   return(0);
}

static void load_ext_blk(char far *loadptr,int loadlen)
{
   int len;
   while ((len = fgetc(fp)) > 0) {
      while (--len >= 0) {
	 if (--loadlen >= 0)
	    *(loadptr++) = fgetc(fp);
	 else
	    fgetc(fp); /* discard excess characters */
	 }
      }
}

static void skip_ext_blk(int *block_len, int *data_len)
{
   int len;
   *data_len = 0;
   *block_len = 1;
   while ((len = fgetc(fp)) > 0) {
      fseek(fp,(long)len,SEEK_CUR);
      *data_len += len;
      *block_len += len + 1;
      }
}


/* switch obsolete fractal types to new generalizations */
static void backwardscompat(struct fractal_info *info)
{
   switch(fractype) {
      case LAMBDASINE:
	 fractype = LAMBDATRIGFP;
	 trigndx[0] = SIN;
	 break;
      case LAMBDACOS	:
	 fractype = LAMBDATRIGFP;
	 trigndx[0] = COS;
	 break;
      case LAMBDAEXP	:
	 fractype = LAMBDATRIGFP;
	 trigndx[0] = EXP;
	 break;
      case MANDELSINE	:
	 fractype = MANDELTRIGFP;
	 trigndx[0] = SIN;
	 break;
      case MANDELCOS	:
	 fractype = MANDELTRIGFP;
	 trigndx[0] = COS;
	 break;
      case MANDELEXP	:
	 fractype = MANDELTRIGFP;
	 trigndx[0] = EXP;
	 break;
      case MANDELSINH	:
	 fractype = MANDELTRIGFP;
	 trigndx[0] = SINH;
	 break;
      case LAMBDASINH	:
	 fractype = LAMBDATRIGFP;
	 trigndx[0] = SINH;
	 break;
      case MANDELCOSH	:
	 fractype = MANDELTRIGFP;
	 trigndx[0] = COSH;
	 break;
      case LAMBDACOSH	:
	 fractype = LAMBDATRIGFP;
	 trigndx[0] = COSH;
	 break;
      case LMANDELSINE	:
	 fractype = MANDELTRIG;
	 trigndx[0] = SIN;
	 break;
      case LLAMBDASINE	:
	 fractype = LAMBDATRIG;
	 trigndx[0] = SIN;
	 break;
      case LMANDELCOS	:
	 fractype = MANDELTRIG;
	 trigndx[0] = COS;
	 break;
      case LLAMBDACOS	:
	 fractype = LAMBDATRIG;
	 trigndx[0] = COS;
	 break;
      case LMANDELSINH	:
	 fractype = MANDELTRIG;
	 trigndx[0] = SINH;
	 break;
      case LLAMBDASINH	:
	 fractype = LAMBDATRIG;
	 trigndx[0] = SINH;
	 break;
      case LMANDELCOSH	:
	 fractype = MANDELTRIG;
	 trigndx[0] = COSH;
	 break;
      case LLAMBDACOSH	:
	 fractype = LAMBDATRIG;
	 trigndx[0] = COSH;
	 break;
      case LMANDELEXP	:
	 fractype = MANDELTRIG;
	 trigndx[0] = EXP;
	 break;
      case LLAMBDAEXP	:
	 fractype = LAMBDATRIG;
	 trigndx[0] = EXP;
	 break;
      case DEMM 	:
	 fractype = MANDELFP;
	 usr_distest = (info->ydots - 1) * 2;
	 break;
      case DEMJ 	:
	 fractype = JULIAFP;
	 usr_distest = (info->ydots - 1) * 2;
	 break;
      case MANDELLAMBDA :
	 useinitorbit = 2;
	 break;
      }
   curfractalspecific = &fractalspecific[fractype];
}

/* switch old bifurcation fractal types to new generalizations */
void set_if_old_bif(void)
{
/* set functions if not set already, may need to check 'functionpreloaded'
   before calling this routine.  JCO 7/5/92 */

   ENTER_OVLY(OVLY_LOADFILE);
   switch(fractype) {
      case BIFURCATION:
      case LBIFURCATION:
      case BIFSTEWART:
      case LBIFSTEWART:
      case BIFLAMBDA:
      case LBIFLAMBDA:
        set_trig_array(0,"ident");
        break;

      case BIFEQSINPI:
      case LBIFEQSINPI:
      case BIFADSINPI:
      case LBIFADSINPI:
        set_trig_array(0,"sin");
        break;
   }
   EXIT_OVLY;
}