93 lines
2.8 KiB
C
93 lines
2.8 KiB
C
/* fifo_string_cache.c
|
|
* A string cache, possibly with a bounded size, using FIFO order to control
|
|
* the size.
|
|
*
|
|
* Wireshark - Network traffic analyzer
|
|
* By Gerald Combs <gerald@wireshark.org>
|
|
* Copyright 1998 Gerald Combs
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0-or-later
|
|
*/
|
|
#include <stdio.h>
|
|
#include "fifo_string_cache.h"
|
|
|
|
void
|
|
fifo_string_cache_init(fifo_string_cache_t *fcache, guint max_entries, GDestroyNotify string_free_func)
|
|
{
|
|
fcache->set = g_hash_table_new_full(g_str_hash, g_str_equal, string_free_func, NULL);
|
|
fcache->head = NULL;
|
|
fcache->tail = NULL;
|
|
fcache->max_entries = max_entries;
|
|
}
|
|
|
|
void
|
|
fifo_string_cache_free(fifo_string_cache_t *fcache)
|
|
{
|
|
if (fcache->set != NULL) {
|
|
g_hash_table_destroy(fcache->set);
|
|
fcache->set = NULL;
|
|
}
|
|
if (fcache->head != NULL) {
|
|
g_slist_free(fcache->head);
|
|
fcache->head = NULL;
|
|
fcache->tail = NULL;
|
|
}
|
|
}
|
|
|
|
gboolean
|
|
fifo_string_cache_contains(fifo_string_cache_t *fcache, const gchar *entry)
|
|
{
|
|
return g_hash_table_contains(fcache->set, entry);
|
|
}
|
|
|
|
gboolean
|
|
fifo_string_cache_insert(fifo_string_cache_t *fcache, const gchar *entry)
|
|
{
|
|
GSList *prev_head;
|
|
GSList *new_start_of_tail;
|
|
|
|
// In GLIB 2.40, g_hash_table_insert() returns a bool that gives us what we
|
|
// need (did the entry exist already?). But, if we're not using that
|
|
// version, we need to first check if the entry exists. So we just check
|
|
// the hash all the time, regardless of GLIB version.
|
|
gboolean exists;
|
|
exists = g_hash_table_contains(fcache->set, entry);
|
|
if (exists) {
|
|
return TRUE;
|
|
}
|
|
|
|
// Shall we remove one item?
|
|
if (fcache->max_entries > 0) {
|
|
if (g_hash_table_size(fcache->set) == fcache->max_entries) {
|
|
g_hash_table_remove(fcache->set, fcache->head->data);
|
|
prev_head = fcache->head;
|
|
fcache->head = fcache->head->next;
|
|
g_slist_free_1(prev_head);
|
|
|
|
// If max_entries is 1, the head was also the tail. Reset the tail.
|
|
if (fcache->tail == prev_head) {
|
|
fcache->tail = NULL;
|
|
}
|
|
|
|
// Now the size of the hash table is max_entries
|
|
}
|
|
}
|
|
|
|
g_hash_table_insert(fcache->set, (gpointer) entry, /*value=*/NULL);
|
|
// Do we need to constrain the number of entries?
|
|
if (fcache->max_entries > 0) {
|
|
// Keep track of the new entry at the end of the queue
|
|
new_start_of_tail = g_slist_append(fcache->tail, (gpointer) entry);
|
|
// Set the new tail
|
|
if (fcache->tail == NULL) {
|
|
fcache->tail = new_start_of_tail;
|
|
// This is the first entry, so head is NULL too. Set it.
|
|
fcache->head = new_start_of_tail;
|
|
} else {
|
|
fcache->tail = new_start_of_tail->next;
|
|
}
|
|
}
|
|
|
|
return FALSE;
|
|
}
|