# 2.11BSD#431 - /usr/src/ucb/pascal/eyacc/ey3.c

##### Functions

    cempty            X
    closure           X
    cpfir             X
    cpres             X
    flset             X
    putitem           X
    stagen            X
    state             X

##### Variables

    cldebug           X
    gsdebug           X
    indebug           X
    pidebug           X

       1: /* (c) 1979 Regents of the University of California */
       2: # include "ey.h"
       3:
       4: cpres(){ /* conpute an array with the beginnings of  productions yielding given nonterminals
       5: 	The array pres points to these lists */
       6:     int i,j,c;
       7:     pres = yalloc(nnonter+1);
       8:     for(i=0;i<=nnonter;i++){
       9:         c = i+NTBASE;
      10:         pres[i] = mem;
      11:         fatfl = 0;  /* make undefined  symbols  nonfatal */
      12:         for(j=0;j<nprod;j++)
      13:         if (*prdptr[j] == c) *mem++ =  prdptr[j]+1;
      14:         if(pres[i] == mem){
      15:             error("nonterminal %s not defined!", nontrst[i].name);
      16:             }
      17:         }
      18:     pres[i] = mem;
      19:     fatfl = 1;
      20:     if( nerrors ){
      21:         summary();
      22:         cexit(1);
      23:         }
      24:     }
      25:
      26: int indebug = 0;
      27: cpfir() {
      28:   /* compute an array with the first of nonterminals */
      29:   int i, ch, **s, **t, changes, *p;
      30:
      31:   pfirst = yalloc(nnonter+1);
      32:   for (i=0;i<=nnonter;i++) {
      33:     aryfil( wsets[i].ws, tbitset, 0 );
      34:     t = pres[i+1];
      35:     for( s=pres[i]; s<t; ++s ){ /* initially fill the sets */
      36:       for( p = *s; (ch = *p) > 0 ; ++p ) {
      37:         if( ch < NTBASE ) {
      38:           wsets[i].ws[ch>>4] |= (1 << (ch&017) );
      39:           break;
      40:           }
      41:         else if( !pempty[ch-NTBASE] ) break;
      42:         }
      43:       }
      44:     }
      45:
      46:   /* now, reflect transitivity */
      47:
      48:   changes = 1;
      49:   while( changes ){
      50:     changes = 0;
      51:     for( i=0; i<=nnonter; ++i ){
      52:       t = pres[i+1];
      53:       for( s=pres[i]; s<t; ++s ){
      54:         for( p = *s; ( ch = (*p-NTBASE) ) >= 0; ++p ) {
      55:           changes |= UNION( wsets[i].ws, wsets[i].ws, wsets[ch].ws );
      56:           if( !pempty[ch] ) break;
      57:           }
      58:         }
      59:       }
      60:     }
      61:
      62:   for( i=0; i<=nnonter; i++ ) pfirst[i] = flset( wsets[i].ws );
      63:   if( !indebug ) return;
      64:   settty();
      65:   for( i=0; i<=nnonter; i++ ){
      66:     fprintf( cout ,  "\n%s: ", nontrst[i].name );
      67:     prlook( pfirst[i] );
      68:     fprintf( cout ,  " %d\n", pempty[i] );
      69:     }
      70:   }
      71:
      72: state(c){ /* sorts last state,and sees if it equals earlier ones. returns state number */
      73:     int s,size1,size2;
      74:     _REGISTER i;
      75:     struct item *p1, *p2, *k, *l, *q1, *q2;
      76:     p1 = pstate[nstate];
      77:     p2 = pstate[nstate+1];
      78:     if(p1==p2) return(0); /* null state */
      79:     /* sort the items */
      80:     for(k=p2-1;k>p1;k--) {  /* make k the biggest */
      81:         for(l=k-1;l>=p1;--l)if( l->pitem > k->pitem ){
      82:             s = k->pitem;
      83:             k->pitem = l->pitem;
      84:             l->pitem = s;
      85:             s = k->look;
      86:             k->look = l->look;
      87:             l->look = s;
      88:             }
      89:         }
      90:     size1 = p2 - p1; /* size of state */
      91:
      92:     for( i= (c>=NTBASE)?ntstates[c-NTBASE]:tstates[c]; i != 0; i = mstates[i] ) {
      93:         /* get ith state */
      94:         q1 = pstate[i];
      95:         q2 = pstate[i+1];
      96:         size2 = q2 - q1;
      97:         if (size1 != size2) continue;
      98:         k=p1;
      99:         for(l=q1;l<q2;l++) {
     100:             if( l->pitem != k->pitem ) break;
     101:             ++k;
     102:             }
     103:         if (l != q2) continue;
     104:         /* found it */
     105:         pstate[nstate+1] = pstate[nstate]; /* delete last state */
     106:         /* fix up lookaheads */
     107:         k=p1;
     108:         for( l=q1; l<q2; ++l ){
     109:             if( UNION( clset.lset, l->look->lset, k->look->lset ) ) {
     110:                 tystate[i] = 1;
     111:                 /* register the new set */
     112:                 l->look = flset( &clset );
     113:                 }
     114:             ++k;
     115:             }
     116:         return (i);
     117:         }
     118: /* state is new */
     119:     pstate[nstate+2] = p2;
     120:     if(nstate+1 >= stsize) error("too many states");
     121:     if( c >= NTBASE ){
     122:         mstates[ nstate ] = ntstates[ c-NTBASE ];
     123:         ntstates[ c-NTBASE ] = nstate;
     124:         }
     125:     else {
     126:         mstates[ nstate ] = tstates[ c ];
     127:         tstates[ c ] = nstate;
     128:         }
     129:     tystate[nstate]=1;
     130:     return(nstate++);
     131:     }
     132:
     133: int pidebug = 0; /* debugging flag for putitem */
     134: putitem ( ptr, lptr )       int *ptr; struct looksets *lptr;{
     135:     int *jip, k;
     136:     struct item *i, *j;
     137:
     138:         if( pidebug ) {
     139:           settty();
     140:       fprintf( cout , "putitem(%s), state %d\n", writem(&ptr), nstate );
     141:           }
     142:     /* see if it's there */
     143:     j = pstate[nstate+1];
     144:         for( i=pstate[nstate]; i<j; ++i )
     145:         if(i->pitem == ptr) {
     146:             error("yacc error--duplicate item");
     147:             }
     148:     /* not there */
     149:     j->pitem = ptr;
     150:     j->look = flset( lptr );
     151:     pstate[nstate+1] = ++j;
     152:     jip = j;
     153:     if(jip-mem0 >= memsiz) error("out of state space");
     154:     }
     155:
     156: cempty(){ /* mark nonterminals which derive the empty string */
     157:
     158:   int i, *p;
     159:
     160:   /* set pempty to 0 */
     161:   pempty = yalloc( nnonter );
     162:   aryfil( pempty, nnonter+1, 0 );
     163:   for( i=1; i<nprod; ++i ) /* loop over productions */
     164:     if( prdptr[i][1] <= 0 ) /* i is empty production */
     165:       pempty[ *prdptr[i]-NTBASE ] = 1;
     166:
     167:   /* now, all explicitly empty nonterminals marked with pempty = 1 */
     168:
     169:   /* loop as long as we keep finding nontrivial empty nonterminals */
     170:
     171: again:
     172:   for( i=1; i<nprod; ++i ){
     173:     if( pempty[ *prdptr[i]-NTBASE ]==0 ){ /* not known to be empty */
     174:       for( p=prdptr[i]+1; *p>=NTBASE && pempty[*p-NTBASE]!=0 ; ++p ) ;
     175:       if( *p < 0 ){ /* we have a nontrivially empty nonterminal */
     176:         pempty[*prdptr[i]-NTBASE] = 1;
     177:         goto again; /* got one ... try for another */
     178:         }
     179:       }
     180:     }
     181:   }
     182:
     183: int gsdebug = 0;
     184: stagen(){ /* generate the states */
     185:
     186:   int i, j, k, c;
     187:
     188:   /* initialize */
     189:
     190:   nstate = 0;
     191:   pstate[0] = pstate[1] = mem;
     192:   aryfil( clset.lset, tbitset, 0 );
     193:   putitem( prdptr[0]+1, &clset );
     194:   tystate[0] = 1;
     195:   nstate = 1;
     196:   pstate[2] = pstate[1];
     197:
     198:   memact = 0;
     199:   aryfil( amem, actsiz, 0 );
     200:
     201:   /* now, the main state generation loop */
     202:
     203:   more:
     204:   for( i=0; i<nstate; ++i ){
     205:     if( tystate[i] != 1 ) continue;
     206:     tystate[i] = 0;
     207:     aryfil( temp1, nterms+nnonter+1, 0 );
     208:     /* take state i, close it, and do gotos */
     209:     closure(i);
     210:     for( j=0; j<cwset; ++j ){ /* generate gotos */
     211:       if( wsets[j].flag ) continue;
     212:       wsets[j].flag = 1;
     213:       c = *(wsets[j].pitem);
     214:       if( c <= 1 ) {
     215:         if( pstate[i+1]-pstate[i] <= j ) tystate[i] = (tystate[i]==1)?1:2;
     216:         continue;
     217:         }
     218:       /* do a goto on c */
     219:       for( k=j; k<cwset; ++k ){
     220:         if( c == *(wsets[k].pitem) ){ /* this item contributes to the goto */
     221:           putitem( wsets[k].pitem + 1, wsets[k].ws );
     222:           wsets[k].flag = 1;
     223:           }
     224:         }
     225:       if( c < NTBASE ) temp1[c] = state(c);
     226:       else temp1[c-NTBASE+nterms] = state(c);
     227:       }
     228:     if( gsdebug ){
     229:       settty();
     230:       fprintf( cout ,  "%d: ", i );
     231:       for( j=1; j<=nterms; ++j ){
     232:         if( temp1[j] != 0 ) fprintf( cout ,  "%s %d, ", symnam(j), temp1[j]);
     233:         }
     234:       for( j=1; j<=nnonter; ++j ){
     235:         if( temp1[j+nterms] ) fprintf( cout ,  "%s %d, ", nontrst[j].name, temp1[j+nterms] );
     236:         }
     237:       fprintf( cout , "\n");
     238:       }
     239:     apstate[i] = apack( &temp1[0], nterms );
     240:     indgo[i] = apack( &temp1[nterms+1], nnonter-1 ) - 1;
     241:     goto more; /* we have done one goto; do some more */
     242:     }
     243:   /* no more to do... stop */
     244:   }
     245:
     246: int cldebug = 0; /* debugging flag for closure */
     247: closure(i){ /* generate the closure of state i */
     248:
     249:   int c, ch, work;
     250:   _REGISTER j, k;
     251:   int *pi;
     252:   int **s, **t;
     253:   struct item *q;
     254:   _REGISTER struct item *p;
     255:
     256:   ++zzclose;
     257:
     258:   /* first, copy kernel of state i to wsets */
     259:
     260:   cwset = 0;
     261:   q = pstate[i+1];
     262:   for( p=pstate[i]; p<q; ++p ){
     263:     wsets[cwset].pitem = p->pitem;
     264:     wsets[cwset].flag = 1;    /* this item must get closed */
     265:     for( k=0; k<tbitset; ++k ) wsets[cwset].ws[k] = p->look->lset[k];
     266:     ++cwset;
     267:     }
     268:
     269:   /* now, go through the loop, closing each item */
     270:
     271:   work = 1;
     272:   while( work ){
     273:     work = 0;
     274:     for( j=0; j<cwset; ++j ){
     275:
     276:       if( wsets[j].flag == 0 ) continue;
     277:       c = *(wsets[j].pitem);  /* dot is before c */
     278:
     279:       if( c < NTBASE ){
     280:         wsets[j].flag = 0;
     281:         continue;  /* only interesting case is where . is before nonterminal */
     282:         }
     283:
     284:       /* compute the lookahead */
     285:       aryfil( clset.lset, tbitset, 0 );
     286:
     287:       /* find items involving c */
     288:
     289:       for( k=j; k<cwset; ++k ){
     290:         if( wsets[k].flag == 1 && *(pi=wsets[k].pitem) == c ){
     291:           wsets[k].flag = 0;
     292:           if( nolook ) continue;
     293:           while( (ch= *++pi)>0 ){
     294:             if( ch < NTBASE ){ /* terminal symbol */
     295:               clset.lset[ch>>4] |= (1<<(ch&017));
     296:               break;
     297:               }
     298:             /* nonterminal symbol */
     299:             UNION( clset.lset, clset.lset, pfirst[ch-NTBASE] );
     300:             if( !pempty[ch-NTBASE] ) break;
     301:             }
     302:           if( ch<=0 ) UNION( clset.lset, clset.lset, wsets[k].ws );
     303:           }
     304:         }
     305:
     306:       /*  now loop over productions derived from c */
     307:
     308:       c -= NTBASE; /* c is now nonterminal number */
     309:
     310:       t = pres[c+1];
     311:       for( s=pres[c]; s<t; ++s ){
     312:         /* put these items into the closure */
     313:         for( k=0; k<cwset; ++k ){ /* is the item there */
     314:           if( wsets[k].pitem == *s ){ /* yes, it is there */
     315:             if( nolook ) goto nexts;
     316:             if( UNION( wsets[k].ws, wsets[k].ws, clset.lset ) ) wsets[k].flag = work = 1;
     317:             goto nexts;
     318:             }
     319:           }
     320:
     321:         /*  not there; make a new entry */
     322:         if( cwset+1 >= wssize ) error( "working set overflow" );
     323:         wsets[cwset].pitem = *s;
     324:         wsets[cwset].flag = 1;
     325:         if( nolook ){
     326:           cwset++;
     327:           goto nexts;
     328:           }
     329:         work = 1;
     330:         for( k=0; k<tbitset; ++k ) wsets[cwset].ws[k] = clset.lset[k];
     331:         cwset++;
     332:
     333:       nexts: ;
     334:         }
     335:
     336:       }
     337:     }
     338:
     339:   /* have computed closure; flags are reset; return */
     340:
     341:   if( cwset > zzcwset ) zzcwset = cwset;
     342:   if( !cldebug ) return;
     343:   settty();
     344:   fprintf( cout , "\nState %d, nolook = %d\n", i, nolook );
     345:   for( j=0; j<cwset; ++j ){
     346:     if( wsets[j].flag ) fprintf( cout , "flag set!\n");
     347:     wsets[j].flag = 0;
     348:     fprintf( cout , "\t%s", writem(&wsets[j].pitem));
     349:     prlook( wsets[j].ws );
     350:     fprintf( cout ,  "\n" );
     351:     }
     352:
     353:   }
     354:
     355: struct looksets *flset( p )
     356:     struct looksets *p;
     357:     {
     358:     /* decide if the lookahead set pointed to by p is known */
     359:     /* return pointer to a perminent location for the set */
     360:
     361:     int j, *w;
     362:     _REGISTER *u, *v, i;
     363:
     364:     for( i=0; i<nlset; ++i ){
     365:         u = p->lset;
     366:         v = lkst[i].lset;
     367:         w = & v[tbitset];
     368:         while( v<w) if( *u++ != *v++ ) goto more;
     369:         /* we have matched */
     370:         return( & lkst[i] );
     371:         more: ;
     372:         }
     373:     /* add a new one */
     374:     if( nlset+1 >= lsetsz )error("too many lookahead sets");
     375:     for( j=0; j<tbitset; ++j ){
     376:         lkst[nlset].lset[j] = p->lset[j];
     377:         }
     378:     return( & lkst[nlset++]);
     379:     }

#### Defined functions

cempty defined in line 156; used 1 times

- in /usr/src/ucb/pascal/eyacc/ey1.c line 77

closure defined in line 247; used 2 times

- in line 209
- in /usr/src/ucb/pascal/eyacc/ey4.c line 13

cpfir defined in line 27; used 1 times

- in /usr/src/ucb/pascal/eyacc/ey1.c line 78

cpres defined in line 4; used 1 times

- in /usr/src/ucb/pascal/eyacc/ey1.c line 76

flset defined in line 355; used 4 times

- in line 62, 112, 150
- in /usr/src/ucb/pascal/eyacc/ey.h line 125

putitem defined in line 134; used 2 times

- in line 193, 221

stagen defined in line 184; used 1 times

- in /usr/src/ucb/pascal/eyacc/ey1.c line 79

state defined in line 72; used 2 times

- in line 225-226(2)

#### Defined variables

cldebug defined in line 246; used 1 times

- in line 342

gsdebug defined in line 183; used 1 times

- in line 228

indebug defined in line 26; used 1 times

- in line 63

pidebug defined in line 133; used 1 times

- in line 138

Last modified: 1981-01-28 Generated: 2016-12-26 | Generated by src2html V0.67 page hit count: 1479 |