/*----------------------------------------------------------------------------*\
 * Sample C program to read a SpinDoctor plot file.
\*----------------------------------------------------------------------------*/
#include <stdlib.h>
#include <stdio.h>

   typedef enum
   {
      EndPlot =  0,   /* End plot; ignore (x,y)      */
      Unused  =  1,   /* Unused; ignore              */
      PenDown =  2,   /* Pen down (draw) to (x,y)    */
      PenUp   =  3,   /* Pen up   (move) to (x,y)    */
      Pen1    =  4,   /* Select pen #1; ignore (x,y) */
      Pen2    =  5,   /* Select pen #2; ignore (x,y) */
      Pen3    =  6,   /* Select pen #3; ignore (x,y) */
      Pen4    =  7,   /* Select pen #4; ignore (x,y) */
      Pen5    =  8,   /* Select pen #5; ignore (x,y) */
      Pen6    =  9,   /* Select pen #6; ignore (x,y) */
      Pen7    = 10,   /* Select pen #7; ignore (x,y) */
      Pen8    = 11    /* Select pen #8; ignore (x,y) */
   } Pcode ;
               
   void plot_point (
      float   x,
      float   y,
      Pcode   i) ;

/*----------------------------------------------------------------------------*\
 * FUNCTION:  main
 * PURPOSE:   To open the plot file, process the data, and close the file.
 *
 * REMARKS:   If argc > 1, then the program reads plot data from the file
 *            named by argv[1].  Else, it reads from stdin.
 *
 * DATE:      2000/09/06  T.W.H.
\*----------------------------------------------------------------------------*/
   int main (
      int    argc,
      char   *argv[])
   {
      FILE    *plot ;
      float   x, y ;
      Pcode   i ;
      int     n, rcode ;
      char    xstr[9], ystr[8], istr[2] ;
   /*
    * Open the input file.
    */
      if (argc > 1)
      {
         if (! (plot = fopen (argv[1], "r")))
         {
            fprintf (stderr, "%s: failed to open input %s\n",
               argv[0], argv[1]) ;
            exit (EXIT_FAILURE) ;
         }
      }
      else
         plot = stdin ;
   /*
    * To parse fields strictly by column alignment without relying on
    * whitespace (which may or may not occur within or between fields), read
    * literal characters into separate strings with %c, then convert those
    * strings.  Note that %f and %s would attempt to parse the plot file on
    * whitespace, which we don't want.
    */
      xstr[8] = ystr[7] = istr[1] = '\0' ;
      rcode   = 0 ;
      do
      {
      /*
       * Parse 5 (x,y,i) triples per input line.
       */
         for (n = 0 ; n < 5 ; n++)
         {
            if ((rcode = fscanf (plot, "%8c%7c%1c", xstr, ystr, istr)) != 3)
               break ;
            sscanf (xstr, "%f", &x) ;
            sscanf (ystr, "%f", &y) ;
            sscanf (istr, "%x", &i) ;
            plot_point (x, y, i) ;
            if (i == EndPlot)
               break ;
         }
      /*
       * End of input line.  Skip over trailing '\r' and '\n' characters.
       */
         fscanf (plot, "%*[\r\n]") ;
      } while ((rcode == 3) && (i != EndPlot)) ;
   /*
    * Close the input file.
    */
      if (plot != stdin)
         fclose (plot) ;
      exit (EXIT_SUCCESS) ;
   }

/*----------------------------------------------------------------------------*\
 * FUNCTION:  plot_point
 * PURPOSE:   To process an (x,y,i) triple from the plot file.
 *
 * ARGS:      x,y   (float) x and y plot coordinates, in inches.
 *            i     (Pcode) command code.
 *
 * REMARKS:   Replace this function with something useful.
 *
 * DATE:      2000/09/06  T.W.H.
\*----------------------------------------------------------------------------*/
   void plot_point (
      float   x,
      float   y,
      Pcode   i)
   {
      static int   n = 0 ;
   /*
    * This simply echos the input to the output in the same plot file format.
    * The second fprintf() inserts '\n' after each set of 5 triples.
    */
      fprintf (stdout, "%8.3f%7.3f%1x", x, y, i) ;
      n = (n + 1) % 5 ;
      if ((n == 0) || (i == EndPlot))
         fprintf (stdout, "\n") ;
   }