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From 1e52fab24dd7dc549c6120ff4c2904be5f1f852b Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Sun, 22 Nov 2015 21:04:51 +0100
Subject: [PATCH hurd 4/4] libihash: fix item insertion
* libihash/ihash.c (find_index): Keep track and return the index where
we could insert the item.
(add_one): Use 'find_index'.
---
libihash/ihash.c | 54 ++++++++++++++++++------------------------------------
1 file changed, 18 insertions(+), 36 deletions(-)
diff --git a/libihash/ihash.c b/libihash/ihash.c
index 8e7383e..ae9f970 100644
--- a/libihash/ihash.c
+++ b/libihash/ihash.c
@@ -73,6 +73,8 @@ find_index (hurd_ihash_t ht, hurd_ihash_key_t key)
{
unsigned int idx;
unsigned int up_idx;
+ unsigned int first_deleted = 0;
+ int first_deleted_set = 0;
unsigned int mask = ht->size - 1;
idx = hash (ht, key) & mask;
@@ -86,15 +88,21 @@ find_index (hurd_ihash_t ht, hurd_ihash_key_t key)
do
{
up_idx = (up_idx + 1) & mask;
- if (ht->items[up_idx].value == _HURD_IHASH_EMPTY
- || compare (ht, ht->items[up_idx].key, key))
+ if (ht->items[up_idx].value == _HURD_IHASH_EMPTY)
+ return first_deleted_set ? first_deleted : up_idx;
+ if (compare (ht, ht->items[up_idx].key, key))
return up_idx;
+ if (! first_deleted_set
+ && ht->items[up_idx].value == _HURD_IHASH_DELETED)
+ first_deleted = up_idx, first_deleted_set = 1;
}
while (up_idx != idx);
- /* If we end up here, the item could not be found. Return any
- invalid index. */
- return idx;
+ /* If we end up here, the item could not be found. Return the index
+ of the first deleted item, as this is the position where we can
+ insert an item with the given key once we established that it is
+ not in the table. */
+ return first_deleted;
}
@@ -231,48 +239,22 @@ static inline int
add_one (hurd_ihash_t ht, hurd_ihash_key_t key, hurd_ihash_value_t value)
{
unsigned int idx;
- unsigned int first_free;
- unsigned int mask = ht->size - 1;
-
- idx = hash (ht, key) & mask;
- first_free = idx;
-
- if (ht->items[idx].value != _HURD_IHASH_EMPTY
- && ! compare (ht, ht->items[idx].key, key))
- {
- unsigned int up_idx = idx;
- do
- {
- up_idx = (up_idx + 1) & mask;
- if (ht->items[up_idx].value == _HURD_IHASH_EMPTY
- || compare (ht, ht->items[up_idx].key, key))
- {
- idx = up_idx;
- break;
- }
- }
- while (up_idx != idx);
- }
+ idx = find_index (ht, key);
/* Remove the old entry for this key if necessary. */
if (index_valid (ht, idx, key))
locp_remove (ht, &ht->items[idx].value);
- /* If we have not found an empty slot, maybe the last one we
- looked at was empty (or just got deleted). */
- if (!index_empty (ht, first_free))
- first_free = idx;
-
- if (index_empty (ht, first_free))
+ if (index_empty (ht, idx))
{
ht->nr_items++;
- ht->items[first_free].value = value;
- ht->items[first_free].key = key;
+ ht->items[idx].value = value;
+ ht->items[idx].key = key;
if (ht->locp_offset != HURD_IHASH_NO_LOCP)
*((hurd_ihash_locp_t *) (((char *) value) + ht->locp_offset))
- = &ht->items[first_free].value;
+ = &ht->items[idx].value;
return 1;
}
--
2.1.4
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