#include "pq_defs.h"
#include "pcp_vars.h"

/* read defining relations and store each relation as a word */

void read_relations (pcp)
struct pcp_vars *pcp;
{
#include "define_y.h"

   register int relp = pcp->relp;
   register int ndrel = pcp->ndrel;

   register int k, l;
   register int type;
   register int length;
   register int disp = 0;

   /* read and store side l of defining relation k;
      each side of a defining relation is stored with its length 
      followed by its exponent followed by the base relator */

   for (k = 1; k <= ndrel; ++k) {
      for (l = 1; l <= 2; ++l) {
         type = l;
                
         ++relp;
#ifdef Magma
         pq_cay_word_to_pq(k, disp, type, pcp);
#else
         read_word (stdin, disp, type, pcp);
#endif

         /* note length of relation */
         length = abs (y[pcp->lused + disp + 1]);

         /* a zero exponent signifies triviality */
         if (y[pcp->lused + disp + 2] == 0) {
            y[relp] = 0;
            continue;
         }

         y[relp] = pcp->lused + 1;
         pcp->lused += length + 1;
      }
   }

   pcp->gspace = pcp->lused + 1;
}