From 19892acc788ecb8e8098abbc36c8cca63858068b Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Fri, 21 Feb 2020 19:35:40 +0100
Subject: [PATCH] do fixpoint iteration on workset for h_first/h_follow
---
src/cfgrammar.c | 47 ++++++++++++++++++++++++++++++++++++-----------
1 file changed, 36 insertions(+), 11 deletions(-)
diff --git a/src/cfgrammar.c b/src/cfgrammar.c
index 47a27f13..5da26c6a 100644
--- a/src/cfgrammar.c
+++ b/src/cfgrammar.c
@@ -393,6 +393,15 @@ bool h_stringmap_equal(const HStringMap *a, const HStringMap *b)
return h_hashtable_equal(a->char_branches, b->char_branches, eq_stringmap);
}
+// helper for h_follow and h_first
+bool workset_equal(HHashTable *a, HHashTable *b)
+{
+ if (a == NULL || b == NULL)
+ return (a == b);
+ else
+ return h_hashtable_equal(a, b, eq_stringmap);
+}
+
static const HStringMap *
h_first_seq_work(size_t k, HCFGrammar *g, HHashTable **pws, HCFChoice **s);
@@ -481,13 +490,18 @@ h_first_work(size_t k, HCFGrammar *g, HHashTable **pws, const HCFChoice *x)
const HStringMap *h_first(size_t k, HCFGrammar *g, const HCFChoice *x)
{
- HHashTable *ws = NULL;
+ HHashTable *ws, *bak;
const HStringMap *ret;
- // XXX perform fixpoint iteration on workset
- ret = h_first_work(k, g, &ws, x);
- assert(ret != NULL);
+ // fixpoint iteration on workset
+ ws = NULL;
+ do {
+ bak = ws;
+ ws = NULL;
+ ret = h_first_work(k, g, &ws, x);
+ } while(!workset_equal(ws, bak));
+ assert(ret != NULL);
return ret;
}
@@ -539,13 +553,18 @@ h_first_seq_work(size_t k, HCFGrammar *g, HHashTable **pws, HCFChoice **s)
const HStringMap *h_first_seq(size_t k, HCFGrammar *g, HCFChoice **s)
{
- HHashTable *ws = NULL;
+ HHashTable *ws, *bak;
const HStringMap *ret;
- // XXX perform fixpoint iteration on workset
- ret = h_first_seq_work(k, g, &ws, s);
- assert(ret != NULL);
+ // fixpoint iteration on workset
+ ws = NULL;
+ do {
+ bak = ws;
+ ws = NULL;
+ ret = h_first_seq_work(k, g, &ws, s);
+ } while(!workset_equal(ws, bak));
+ assert(ret != NULL);
return ret;
}
@@ -718,12 +737,18 @@ h_follow_work(size_t k, HCFGrammar *g, HHashTable **pws, const HCFChoice *x)
const HStringMap *h_follow(size_t k, HCFGrammar *g, const HCFChoice *x)
{
- HHashTable *ws = NULL;
+ HHashTable *ws, *bak;
const HStringMap *ret;
- // XXX perform fixpoint iteration on workset
- ret = h_follow_work(k, g, &ws, x);
+ // fixpoint iteration on workset
+ ws = NULL;
+ do {
+ bak = ws;
+ ws = NULL;
+ ret = h_follow_work(k, g, &ws, x);
+ } while(!workset_equal(ws, bak));
+ assert(ret != NULL);
return ret;
}
--
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