From ab15dd054b3c30328088c380288ccef479f7538b Mon Sep 17 00:00:00 2001
From: hniksic <devnull@localhost>
Date: Fri, 7 Nov 2003 03:40:08 -0800
Subject: [PATCH] [svn] Allow NULL/0 as hash table keys.
---
src/ChangeLog | 9 +++++++++
src/hash.c | 18 +++++++++++++-----
2 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/src/ChangeLog b/src/ChangeLog
index bf5f6ccb..7227bdfb 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2003-11-07 Hrvoje Niksic <hniksic@xemacs.org>
+
+ * hash.c (NON_EMPTY): Use the all-bit-set value as the marker that
+ the field is empty. This allows NULL pointer and 0 value to be
+ used as keys, which is necessary for the connect.c code to work
+ when fd==0.
+ (hash_table_new): Fill mappings with 0xff.
+ (grow_hash_table): Ditto.
+
2003-11-07 Hrvoje Niksic <hniksic@xemacs.org>
* url.c (url_parse): Allow empty ports.
diff --git a/src/hash.c b/src/hash.c
index b72fac71..ed8cac1e 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -175,9 +175,10 @@ struct hash_table {
struct mapping *mappings; /* the array of mapping pairs. */
};
-/* We use NULL key to mark a mapping as empty. It is consequently
- illegal to store NULL keys. */
-#define NON_EMPTY(mp) (mp->key != NULL)
+/* We use all-bit-set marker to mean that a mapping is empty. It is
+ (hopefully) illegal as a pointer, and it allows the users to use
+ NULL (as well as any non-negative integer) as key. */
+#define NON_EMPTY(mp) (mp->key != (void *)~(unsigned long)0)
/* "Next" mapping is the mapping after MP, but wrapping back to
MAPPINGS when MP would reach MAPPINGS+SIZE. */
@@ -284,7 +285,11 @@ hash_table_new (int items,
ht->resize_threshold = size * HASH_MAX_FULLNESS;
/*assert (ht->resize_threshold >= items);*/
- ht->mappings = xnew0_array (struct mapping, ht->size);
+ ht->mappings = xnew_array (struct mapping, ht->size);
+ /* Mark mappings as empty. We use 0xff rather than 0 to mark empty
+ keys because it allows us to store NULL keys to the table. */
+ memset (ht->mappings, 255, size * sizeof (struct mapping));
+
ht->count = 0;
return ht;
@@ -384,7 +389,10 @@ grow_hash_table (struct hash_table *ht)
ht->size = newsize;
ht->resize_threshold = newsize * HASH_MAX_FULLNESS;
- ht->mappings = mappings = xnew0_array (struct mapping, ht->size);
+
+ mappings = xnew_array (struct mapping, newsize);
+ memset (mappings, 255, newsize * sizeof (struct mapping));
+ ht->mappings = mappings;
for (mp = old_mappings; mp < old_end; mp++)
if (NON_EMPTY (mp))