Added Berkeley Yacc sources

util/byacc/closure.c

@@ -0,0 +1,265 @@
+#include "defs.h"
+
+short *itemset;
+short *itemsetend;
+unsigned *ruleset;
+
+static unsigned *first_derives;
+static unsigned *EFF;
+
+
+set_EFF()
+{
+    register unsigned *row;
+    register int symbol;
+    register short *sp;
+    register int rowsize;
+    register int i;
+    register int rule;
+
+    rowsize = WORDSIZE(nvars);
+    EFF = NEW2(nvars * rowsize, unsigned);
+
+    row = EFF;
+    for (i = start_symbol; i < nsyms; i++)
+    {
+	sp = derives[i];
+	for (rule = *sp; rule > 0; rule = *++sp)
+	{
+	    symbol = ritem[rrhs[rule]];
+	    if (ISVAR(symbol))
+	    {
+		symbol -= start_symbol;
+		SETBIT(row, symbol);
+	    }
+	}
+	row += rowsize;
+    }
+
+    reflexive_transitive_closure(EFF, nvars);
+
+#ifdef	DEBUG
+    print_EFF();
+#endif
+}
+
+
+set_first_derives()
+{
+  register unsigned *rrow;
+  register unsigned *vrow;
+  register int j;
+  register unsigned mask;
+  register unsigned cword;
+  register short *rp;
+
+  int rule;
+  int i;
+  int rulesetsize;
+  int varsetsize;
+
+  rulesetsize = WORDSIZE(nrules);
+  varsetsize = WORDSIZE(nvars);
+  first_derives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
+
+  set_EFF();
+
+  rrow = first_derives + ntokens * rulesetsize;
+  for (i = start_symbol; i < nsyms; i++)
+    {
+      vrow = EFF + ((i - ntokens) * varsetsize);
+      cword = *vrow++;
+      mask = 1;
+      for (j = start_symbol; j < nsyms; j++)
+	{
+	  if (cword & mask)
+	    {
+	      rp = derives[j];
+	      while ((rule = *rp++) >= 0)
+		{
+		  SETBIT(rrow, rule);
+		}
+	    }
+
+	  mask <<= 1;
+	  if (mask == 0)
+	    {
+	      cword = *vrow++;
+	      mask = 1;
+	    }
+	}
+
+      vrow += varsetsize;
+      rrow += rulesetsize;
+    }
+
+#ifdef	DEBUG
+  print_first_derives();
+#endif
+
+  FREE(EFF);
+}
+
+
+closure(nucleus, n)
+short *nucleus;
+int n;
+{
+    register int ruleno;
+    register unsigned word;
+    register unsigned mask;
+    register short *csp;
+    register unsigned *dsp;
+    register unsigned *rsp;
+    register int rulesetsize;
+
+    short *csend;
+    unsigned *rsend;
+    int symbol;
+    int itemno;
+
+    rulesetsize = WORDSIZE(nrules);
+    rsp = ruleset;
+    rsend = ruleset + rulesetsize;
+    for (rsp = ruleset; rsp < rsend; rsp++)
+	*rsp = 0;
+
+    csend = nucleus + n;
+    for (csp = nucleus; csp < csend; ++csp)
+    {
+	symbol = ritem[*csp];
+	if (ISVAR(symbol))
+	{
+	    dsp = first_derives + symbol * rulesetsize;
+	    rsp = ruleset;
+	    while (rsp < rsend)
+		*rsp++ |= *dsp++;
+	}
+    }
+
+    ruleno = 0;
+    itemsetend = itemset;
+    csp = nucleus;
+    for (rsp = ruleset; rsp < rsend; ++rsp)
+    {
+	word = *rsp;
+	if (word == 0)
+	    ruleno += BITS_PER_WORD;
+	else
+	{
+	    mask = 1;
+	    while (mask)
+	    {
+		if (word & mask)
+		{
+		    itemno = rrhs[ruleno];
+		    while (csp < csend && *csp < itemno)
+			*itemsetend++ = *csp++;
+		    *itemsetend++ = itemno;
+		    while (csp < csend && *csp == itemno)
+			++csp;
+		}
+
+		    mask <<= 1;
+		    ++ruleno;
+	    }
+	}
+    }
+
+    while (csp < csend)
+	*itemsetend++ = *csp++;
+
+#ifdef	DEBUG
+  print_closure(n);
+#endif
+}
+
+
+
+finalize_closure()
+{
+  FREE(itemset);
+  FREE(ruleset);
+  FREE(first_derives + ntokens * WORDSIZE(nrules));
+}
+
+
+#ifdef	DEBUG
+
+print_closure(n)
+int n;
+{
+  register short *isp;
+
+  printf("\n\nn = %d\n\n", n);
+  for (isp = itemset; isp < itemsetend; isp++)
+    printf("   %d\n", *isp);
+}
+
+
+print_EFF()
+{
+    register int i, j, k;
+    register unsigned *rowp;
+    register unsigned word;
+    register unsigned mask;
+
+    printf("\n\nEpsilon Free Firsts\n");
+
+    for (i = start_symbol; i < nsyms; i++)
+    {
+	printf("\n%s", symbol_name[i]);
+	rowp = EFF + ((i - start_symbol) * WORDSIZE(nvars));
+	word = *rowp++;
+
+	mask = 1;
+	for (j = 0; j < nvars; j++)
+	{
+	    if (word & mask)
+		printf("  %s", symbol_name[start_symbol + j]);
+
+	    mask <<= 1;
+	    if (mask == 0)
+	    {
+		word = *rowp++;
+		mask = 1;
+	    }
+	}
+    }
+}
+
+
+print_first_derives()
+{
+  register int i;
+  register int j;
+  register unsigned *rp;
+  register unsigned cword;
+  register unsigned mask;
+
+  printf("\n\n\nFirst Derives\n");
+
+  for (i = start_symbol; i < nsyms; i++)
+    {
+      printf("\n%s derives\n", symbol_name[i]);
+      rp = first_derives + i * WORDSIZE(nrules);
+      cword = *rp++;
+      mask = 1;
+      for (j = 0; j <= nrules; j++)
+        {
+	  if (cword & mask)
+	    printf("   %d\n", j);
+
+	  mask <<= 1;
+	  if (mask == 0)
+	    {
+	      cword = *rp++;
+	      mask = 1;
+	    }
+	}
+    }
+
+  fflush(stdout);
+}
+
+#endif