#include "pgenheaders.h"

#include "grammar.h"

#include "token.h"

extern int Py_DebugFlag;

static void calcfirstset(grammar *, dfa *);

addfirstsets(grammar *g)

{

int i;

dfa *d;

if (Py_DebugFlag)

printf("Adding FIRST sets ...\n");

for (i = 0; i < g->g_ndfas; i++) {

d = &g->g_dfa[i];

if (d->d_first == NULL)

calcfirstset(g, d);

}

}

static void

calcfirstset(grammar *g, dfa *d)

{

int i, j;

state *s;

arc *a;

int nsyms;

int *sym;

int nbits;

static bitset dummy;

bitset result;

int type;

dfa *d1;

label *l0;

if (Py_DebugFlag)

printf("Calculate FIRST set for '%s'\n", d->d_name);

if (dummy == NULL)

dummy = newbitset(1);

if (d->d_first == dummy) {

fprintf(stderr, "Left-recursion for '%s'\n", d->d_name);

return;

}

if (d->d_first != NULL) {

fprintf(stderr, "Re-calculating FIRST set for '%s' ???\n",

d->d_name);

}

d->d_first = dummy;

l0 = g->g_ll.ll_label;

nbits = g->g_ll.ll_nlabels;

result = newbitset(nbits);

sym = (int *)PyObject_MALLOC(sizeof(int));

if (sym == NULL)

Py_FatalError("no mem for new sym in calcfirstset");

nsyms = 1;

sym[0] = findlabel(&g->g_ll, d->d_type, (char *)NULL);

s = &d->d_state[d->d_initial];

for (i = 0; i < s->s_narcs; i++) {

a = &s->s_arc[i];

for (j = 0; j < nsyms; j++) {

if (sym[j] == a->a_lbl)

break;

}

if (j >= nsyms) { /* New label */

sym = (int *)PyObject_REALLOC(sym,

sizeof(int) * (nsyms + 1));

if (sym == NULL)

Py_FatalError(

"no mem to resize sym in calcfirstset");

sym[nsyms++] = a->a_lbl;

type = l0[a->a_lbl].lb_type;

if (ISNONTERMINAL(type)) {

d1 = PyGrammar_FindDFA(g, type);

if (d1->d_first == dummy) {

fprintf(stderr,

"Left-recursion below '%s'\n",

d->d_name);

}

else {

if (d1->d_first == NULL)

calcfirstset(g, d1);

mergebitset(result,

d1->d_first, nbits);

}

}

else if (ISTERMINAL(type)) {

addbit(result, a->a_lbl);

}

}

}

d->d_first = result;

if (Py_DebugFlag) {

printf("FIRST set for '%s': {", d->d_name);

for (i = 0; i < nbits; i++) {

if (testbit(result, i))

printf(" %s", PyGrammar_LabelRepr(&l0[i]));

}

printf(" }\n");

}

PyObject_FREE(sym);

}