1 files changed, 101 insertions, 0 deletions
diff --git a/Parser/acceler.c b/Parser/acceler.c
new file mode 100644
index 0000000..7ff10b2
--- /dev/null
+++ b/Parser/acceler.c
@@ -0,0 +1,101 @@
+/* Parser accelerator module */
+
+#include <stdio.h>
+
+#include "PROTO.h"
+#include "grammar.h"
+#include "token.h"
+#include "malloc.h"
+
+static void
+fixstate(g, d, s)
+	grammar *g;
+	dfa *d;
+	state *s;
+{
+	arc *a;
+	int k;
+	int *accel;
+	int nl = g->g_ll.ll_nlabels;
+	s->s_accept = 0;
+	accel = NEW(int, nl);
+	for (k = 0; k < nl; k++)
+		accel[k] = -1;
+	a = s->s_arc;
+	for (k = s->s_narcs; --k >= 0; a++) {
+		int lbl = a->a_lbl;
+		label *l = &g->g_ll.ll_label[lbl];
+		int type = l->lb_type;
+		if (a->a_arrow >= (1 << 7)) {
+			printf("XXX too many states!\n");
+			continue;
+		}
+		if (ISNONTERMINAL(type)) {
+			dfa *d1 = finddfa(g, type);
+			int ibit;
+			if (type - NT_OFFSET >= (1 << 7)) {
+				printf("XXX too high nonterminal number!\n");
+				continue;
+			}
+			for (ibit = 0; ibit < g->g_ll.ll_nlabels; ibit++) {
+				if (testbit(d1->d_first, ibit)) {
+					if (accel[ibit] != -1)
+						printf("XXX ambiguity!\n");
+					accel[ibit] = a->a_arrow | (1 << 7) |
+						((type - NT_OFFSET) << 8);
+				}
+			}
+		}
+		else if (lbl == EMPTY)
+			s->s_accept = 1;
+		else if (lbl >= 0 && lbl < nl)
+			accel[lbl] = a->a_arrow;
+	}
+	while (nl > 0 && accel[nl-1] == -1)
+		nl--;
+	for (k = 0; k < nl && accel[k] == -1;)
+		k++;
+	if (k < nl) {
+		int i;
+		s->s_accel = NEW(int, nl-k);
+		if (s->s_accel == NULL) {
+			fprintf(stderr, "no mem to add parser accelerators\n");
+			exit(1);
+		}
+		s->s_lower = k;
+		s->s_upper = nl;
+		for (i = 0; k < nl; i++, k++)
+			s->s_accel[i] = accel[k];
+	}
+	DEL(accel);
+}
+
+static void
+fixdfa(g, d)
+	grammar *g;
+	dfa *d;
+{
+	state *s;
+	int j;
+	s = d->d_state;
+	for (j = 0; j < d->d_nstates; j++, s++)
+		fixstate(g, d, s);
+}
+
+void
+addaccelerators(g)
+	grammar *g;
+{
+	dfa *d;
+	int i;
+#ifdef DEBUG
+	printf("Adding parser accellerators ...\n");
+#endif
+	d = g->g_dfa;
+	for (i = g->g_ndfas; --i >= 0; d++)
+		fixdfa(g, d);
+	g->g_accel = 1;
+#ifdef DEBUG
+	printf("Done.\n");
+#endif
+}