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* src/nullable.c (set_nullable): Deobfuscate the handling of

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ritem.
`symbol >= 0' is wrong now, use `rule_table[ruleno].useful'.
This commit is contained in:
Akim Demaille
2001-12-05 09:16:22 +00:00
parent 2dfb4daf9b
commit d854cc9e5a
2 changed files with 34 additions and 33 deletions
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60
src/nullable.c
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@@ -71,41 +71,35 @@ set_nullable (void)
relts = XCALLOC (shorts, nitems + nvars + 1);
p = relts;
r = ritem;
while (*r)
for (r = ritem; *r; ++r)
{
if (*r < 0)
{
int symbol = rule_table[-(*r++)].lhs;
if (symbol >= 0 && !nullable[symbol])
{
nullable[symbol] = 1;
*s2++ = symbol;
}
}
else
{
int any_tokens = 0;
int symbol;
short *r1 = r;
for (symbol = *r++; symbol > 0; symbol = *r++)
if (ISTOKEN (symbol))
any_tokens = 1;
/* Walk RITEM to find (i), if there are any tokens in the
RHS, and (ii), to find RULENO. */
int ruleno;
int any_tokens = 0;
short *r1;
for (r1 = r; *r1 > 0; ++r1)
if (ISTOKEN (*r1))
any_tokens = 1;
ruleno = -*r1;
if (!any_tokens)
{
int ruleno = -symbol;
r = r1;
for (symbol = *r++; symbol > 0; symbol = *r++)
{
rcount[ruleno]++;
p->next = rsets[symbol];
p->value = ruleno;
rsets[symbol] = p;
p++;
}
}
}
/* Examine the RHS of the rule. */
if (!any_tokens)
for (/* Nothing. */; *r > 0; ++r)
{
rcount[ruleno]++;
p->next = rsets[*r];
p->value = ruleno;
rsets[*r] = p;
p++;
}
/* Examine its LHS. */
if (rule_table[ruleno].useful && !nullable[rule_table[ruleno].lhs])
{
nullable[rule_table[ruleno].lhs] = 1;
*s2++ = rule_table[ruleno].lhs;
}
}
while (s1 < s2)