Changeset 0db0df2 in mainline for uspace/srv/fs/fat/fat_idx.c

Timestamp:

2025-04-07T17:53:53Z (9 days ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

master

Children:

0c6fc7a, 45226285, 93de384, e92052d

Parents:

8f8818ac

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2025-04-07 16:41:57)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2025-04-07 17:53:53)

Message:

Hash table improvements

Implement hash_table_foreach macro, analogous to list_foreach.

Remove superfluous argument to hash_table_find_next().
(If the user needs to recheck the part of the list already
checked by hash_table_find(), they can just rerun that function.)

Add hash argument to hash_table_ops_t::key_equal.
The big change here is that users with big keys can store the hash
value alongside key in their entries, and for the low low cost of
sizeof(size_t) bytes eliminate a bunch of expensive key comparisons.

Also added a hash function for strings and arbitrary data.
Found this one by asking ChatGPT, because the latency of accesses
to my book collection is currently a couple of hours.

+ Some drive-by unused #include removal.

File:

• uspace/srv/fs/fat/fat_idx.c (modified) (3 diffs)

uspace/srv/fs/fat/fat_idx.c

@@ -37 +37 @@
 
 #include "fat.h"
-#include "../../vfs/vfs.h"
 #include <errno.h>
 #include <str.h>
@@ -139 +138 @@
 }
 
-static bool pos_key_equal(const void *key, const ht_link_t *item)
+static bool pos_key_equal(const void *key, size_t hash, const ht_link_t *item)
 {
         const pos_key_t *pos = key;
@@ -180 +179 @@
 }
 
-static bool idx_key_equal(const void *key_arg, const ht_link_t *item)
+static bool idx_key_equal(const void *key_arg, size_t hash,
+    const ht_link_t *item)
 {
         fat_idx_t *fidx = hash_table_get_inst(item, fat_idx_t, uih_link);