symtabs: allow to modify the list during iteration over it.

* include/grecs/list.h (grecs_list_remove): New proto.
* include/grecs/symtab.h (grecs_symtab_count_entries):
Rename to grecs_symtab_count.
* src/list.c (grecs_list_remove): New function.
(grecs_list_remove_tail, grecs_list_clear)
(grecs_list_locate,grecs_list_index): Treat NULL list
as empty list.
* src/symtab.c: Defer table modifications during iteration
(symtab_defer_type): New enum.
(grecs_symtab)<elcount,itr_level,defer_list>: New members.
(symtab_defer_op): New static function.
(grecs_symtab_remove): When called during iteration, add the
entry to the defer_del deferment list, unless it is already
in defer_add, in which case remove it from there.
Update elcount.
(grecs_symtab_lookup_or_install): Defer addition when iterating.
Update elcount.
(grecs_symtab_clear): Reset elcount to 0.
(grecs_symtab_create): Initialize elcount.
(grecs_symtab_foreach): Process deferred modifications.

1 files changed, 59 insertions, 25 deletions

diff --git a/src/list.c b/src/list.c
index b2d9f13..afd1b5d 100644
--- a/src/list.c
+++ b/src/list.c
@@ -86,6 +86,46 @@ grecs_list_remove_entry(struct grecs_list *lp, struct grecs_list_entry *ent)
 	lp->count--;
 }
 
+void *
+grecs_list_remove_tail(struct grecs_list *lp)
+{
+	void *data;
+	struct grecs_list_entry *ep;
+  
+	if (!lp || !lp->tail)
+		return NULL;
+	ep = lp->tail;
+	data = lp->tail->data;
+	grecs_list_remove_entry(lp, ep);
+	return data;
+}
+
+static int
+_ptrcmp(const void *a, const void *b)
+{
+	return a != b;
+}
+
+int
+grecs_list_remove(struct grecs_list *lp, void *data)
+{
+	struct grecs_list_entry *ep;
+	int (*cmp)(const void *, const void *);
+
+
+	if (!lp)
+		return 1;
+	
+	cmp = lp->cmp ? lp->cmp : _ptrcmp;
+	for (ep = lp->head; ep; ep = ep->next) {
+		if (cmp(ep->data, data) == 0) {
+			grecs_list_remove_entry(lp, ep);
+			return 0;
+		}
+	}
+	return 1;
+}
+
 void
 grecs_list_append(struct grecs_list *lp, void *val)
 {
@@ -123,7 +163,11 @@ void *
 grecs_list_pop(struct grecs_list *lp)
 {
 	void *data;
-	struct grecs_list_entry *ep = lp->head;
+	struct grecs_list_entry *ep;
+
+	if (!lp)
+		return NULL;
+	ep = lp->head;
 	if (ep)	{
 		data = ep->data;
 		grecs_list_remove_entry(lp, ep);
@@ -132,25 +176,14 @@ grecs_list_pop(struct grecs_list *lp)
 	return data;
 }
 
-void *
-grecs_list_remove_tail(struct grecs_list *lp)
-{
-	void *data;
-	struct grecs_list_entry *ep;
-  
-	if (!lp->tail)
-		return NULL;
-	ep = lp->tail;
-	data = lp->tail->data;
-	grecs_list_remove_entry(lp, ep);
-	return data;
-}
-
 void
 grecs_list_clear(struct grecs_list *lp)
 {
-	struct grecs_list_entry *ep = lp->head;
+	struct grecs_list_entry *ep;
 
+	if (!lp)
+		return;
+	ep = lp->head;
 	while (ep) {
 		struct grecs_list_entry *next = ep->next;
 		if (lp->free_entry)
@@ -171,17 +204,16 @@ grecs_list_free(struct grecs_list *lp)
 	}
 }
 
-static int
-_ptrcmp(const void *a, const void *b)
-{
-	return a != b;
-}
-
 void *
 grecs_list_locate(struct grecs_list *lp, void *data)
 {
 	struct grecs_list_entry *ep;
-	int (*cmp)(const void *, const void *) = lp->cmp ? lp->cmp : _ptrcmp;
+	int (*cmp)(const void *, const void *);
+
+	if (!lp)
+		return NULL;
+	
+	cmp = lp->cmp ? lp->cmp : _ptrcmp;
 
 	for (ep = lp->head; ep; ep = ep->next) {
 		if (cmp(ep->data, data) == 0)
@@ -194,7 +226,9 @@ void *
 grecs_list_index(struct grecs_list *lp, size_t idx)
 {
 	struct grecs_list_entry *ep;
-	
+
+	if (!lp)
+		return NULL;
 	for (ep = lp->head; ep && idx; ep = ep->next, idx--)
 		;
 	return ep ? ep->data : NULL;
@@ -219,7 +253,7 @@ grecs_list_compare(struct grecs_list *a, struct grecs_list *b)
 	cmp = a->cmp ? a->cmp : _ptrcmp;
 	
 	for (ap = a->head, bp = b->head; ap; ap = ap->next, bp = bp->next)
-		if (cmp (ap->data, bp->data))
+		if (cmp(ap->data, bp->data))
 			return 1;
 	
 	return 0;