Commit c1b9203e authored by Kristian Høgsberg's avatar Kristian Høgsberg
Browse files

Drop unused hash table

We now just use a table for looking up object IDs so we should drop the
hash table.
parent bc79f1f8
......@@ -14,8 +14,7 @@ libwayland_util_la_SOURCES = \
connection.h \
wayland-util.c \
wayland-util.h \
wayland-private.h \
wayland-hash.c
wayland-private.h
libwayland_server_la_LIBADD = $(FFI_LIBS) libwayland-util.la -lrt
libwayland_server_la_SOURCES = \
......
/*
* Copyright © 2009 Intel Corporation
* Copyright © 1988-2004 Keith Packard and Bart Massey.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Except as contained in this notice, the names of the authors
* or their institutions shall not be used in advertising or
* otherwise to promote the sale, use or other dealings in this
* Software without prior written authorization from the
* authors.
*
* Authors:
* Eric Anholt <eric@anholt.net>
* Keith Packard <keithp@keithp.com>
*/
#include <stdlib.h>
#include "wayland-util.h"
struct hash_entry {
uint32_t hash;
void *data;
};
struct wl_hash_table {
struct hash_entry *table;
uint32_t size;
uint32_t rehash;
uint32_t max_entries;
uint32_t size_index;
uint32_t entries;
uint32_t deleted_entries;
};
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
/*
* From Knuth -- a good choice for hash/rehash values is p, p-2 where
* p and p-2 are both prime. These tables are sized to have an extra 10%
* free to avoid exponential performance degradation as the hash table fills
*/
static const uint32_t deleted_data;
static const struct {
uint32_t max_entries, size, rehash;
} hash_sizes[] = {
{ 2, 5, 3 },
{ 4, 7, 5 },
{ 8, 13, 11 },
{ 16, 19, 17 },
{ 32, 43, 41 },
{ 64, 73, 71 },
{ 128, 151, 149 },
{ 256, 283, 281 },
{ 512, 571, 569 },
{ 1024, 1153, 1151 },
{ 2048, 2269, 2267 },
{ 4096, 4519, 4517 },
{ 8192, 9013, 9011 },
{ 16384, 18043, 18041 },
{ 32768, 36109, 36107 },
{ 65536, 72091, 72089 },
{ 131072, 144409, 144407 },
{ 262144, 288361, 288359 },
{ 524288, 576883, 576881 },
{ 1048576, 1153459, 1153457 },
{ 2097152, 2307163, 2307161 },
{ 4194304, 4613893, 4613891 },
{ 8388608, 9227641, 9227639 },
{ 16777216, 18455029, 18455027 },
{ 33554432, 36911011, 36911009 },
{ 67108864, 73819861, 73819859 },
{ 134217728, 147639589, 147639587 },
{ 268435456, 295279081, 295279079 },
{ 536870912, 590559793, 590559791 },
{ 1073741824, 1181116273, 1181116271},
{ 2147483648ul, 2362232233ul, 2362232231ul}
};
static int
entry_is_free(struct hash_entry *entry)
{
return entry->data == NULL;
}
static int
entry_is_deleted(struct hash_entry *entry)
{
return entry->data == &deleted_data;
}
static int
entry_is_present(struct hash_entry *entry)
{
return entry->data != NULL && entry->data != &deleted_data;
}
WL_EXPORT struct wl_hash_table *
wl_hash_table_create(void)
{
struct wl_hash_table *ht;
ht = malloc(sizeof(*ht));
if (ht == NULL)
return NULL;
ht->size_index = 0;
ht->size = hash_sizes[ht->size_index].size;
ht->rehash = hash_sizes[ht->size_index].rehash;
ht->max_entries = hash_sizes[ht->size_index].max_entries;
ht->table = calloc(ht->size, sizeof(*ht->table));
ht->entries = 0;
ht->deleted_entries = 0;
if (ht->table == NULL) {
free(ht);
return NULL;
}
return ht;
}
/**
* Frees the given hash table.
*/
WL_EXPORT void
wl_hash_table_destroy(struct wl_hash_table *ht)
{
if (!ht)
return;
free(ht->table);
free(ht);
}
/**
* Finds a hash table entry with the given key and hash of that key.
*
* Returns NULL if no entry is found. Note that the data pointer may be
* modified by the user.
*/
static void *
hash_table_search(struct wl_hash_table *ht, uint32_t hash)
{
uint32_t hash_address;
hash_address = hash % ht->size;
do {
uint32_t double_hash;
struct hash_entry *entry = ht->table + hash_address;
if (entry_is_free(entry)) {
return NULL;
} else if (entry_is_present(entry) && entry->hash == hash) {
return entry;
}
double_hash = 1 + hash % ht->rehash;
hash_address = (hash_address + double_hash) % ht->size;
} while (hash_address != hash % ht->size);
return NULL;
}
WL_EXPORT void
wl_hash_table_for_each(struct wl_hash_table *ht,
wl_iterator_func_t func, void *data)
{
struct hash_entry *entry;
uint32_t i;
for (i = 0; i < ht->size; i++) {
entry = ht->table + i;
if (entry_is_present(entry))
func(entry->data, data);
}
}
WL_EXPORT void *
wl_hash_table_lookup(struct wl_hash_table *ht, uint32_t hash)
{
struct hash_entry *entry;
entry = hash_table_search(ht, hash);
if (entry != NULL)
return entry->data;
return NULL;
}
static void
hash_table_rehash(struct wl_hash_table *ht, int new_size_index)
{
struct wl_hash_table old_ht;
struct hash_entry *table, *entry;
if (new_size_index >= ARRAY_SIZE(hash_sizes))
return;
table = calloc(hash_sizes[new_size_index].size, sizeof(*ht->table));
if (table == NULL)
return;
old_ht = *ht;
ht->table = table;
ht->size_index = new_size_index;
ht->size = hash_sizes[ht->size_index].size;
ht->rehash = hash_sizes[ht->size_index].rehash;
ht->max_entries = hash_sizes[ht->size_index].max_entries;
ht->entries = 0;
ht->deleted_entries = 0;
for (entry = old_ht.table;
entry != old_ht.table + old_ht.size;
entry++) {
if (entry_is_present(entry)) {
wl_hash_table_insert(ht, entry->hash, entry->data);
}
}
free(old_ht.table);
}
/**
* Inserts the data with the given hash into the table.
*
* Note that insertion may rearrange the table on a resize or rehash,
* so previously found hash_entries are no longer valid after this function.
*/
WL_EXPORT int
wl_hash_table_insert(struct wl_hash_table *ht, uint32_t hash, void *data)
{
uint32_t hash_address;
if (ht->entries >= ht->max_entries) {
hash_table_rehash(ht, ht->size_index + 1);
} else if (ht->deleted_entries + ht->entries >= ht->max_entries) {
hash_table_rehash(ht, ht->size_index);
}
hash_address = hash % ht->size;
do {
struct hash_entry *entry = ht->table + hash_address;
uint32_t double_hash;
if (!entry_is_present(entry)) {
if (entry_is_deleted(entry))
ht->deleted_entries--;
entry->hash = hash;
entry->data = data;
ht->entries++;
return 0;
}
double_hash = 1 + hash % ht->rehash;
hash_address = (hash_address + double_hash) % ht->size;
} while (hash_address != hash % ht->size);
/* We could hit here if a required resize failed. An unchecked-malloc
* application could ignore this result.
*/
return -1;
}
/**
* This function deletes the given hash table entry.
*
* Note that deletion doesn't otherwise modify the table, so an iteration over
* the table deleting entries is safe.
*/
WL_EXPORT void
wl_hash_table_remove(struct wl_hash_table *ht, uint32_t hash)
{
struct hash_entry *entry;
entry = hash_table_search(ht, hash);
if (entry != NULL) {
entry->data = (void *) &deleted_data;
ht->entries--;
ht->deleted_entries++;
}
}
......@@ -39,6 +39,8 @@ struct wl_map {
uint32_t free_list;
};
typedef void (*wl_iterator_func_t)(void *element, void *data);
void wl_map_init(struct wl_map *map);
void wl_map_release(struct wl_map *map);
uint32_t wl_map_insert_new(struct wl_map *map, uint32_t side, void *data);
......
......@@ -65,17 +65,6 @@ struct wl_object {
uint32_t id;
};
typedef void (*wl_iterator_func_t)(void *element, void *data);
struct wl_hash_table;
struct wl_hash_table *wl_hash_table_create(void);
void wl_hash_table_destroy(struct wl_hash_table *ht);
void *wl_hash_table_lookup(struct wl_hash_table *ht, uint32_t hash);
int wl_hash_table_insert(struct wl_hash_table *ht, uint32_t hash, void *data);
void wl_hash_table_remove(struct wl_hash_table *ht, uint32_t hash);
void wl_hash_table_for_each(struct wl_hash_table *ht,
wl_iterator_func_t func, void *data);
/**
* wl_list - linked list
*
......
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