summaryrefslogtreecommitdiffstats
path: root/src/libopkg/.svn/text-base/hash_table.c.svn-base
diff options
context:
space:
mode:
Diffstat (limited to 'src/libopkg/.svn/text-base/hash_table.c.svn-base')
-rw-r--r--src/libopkg/.svn/text-base/hash_table.c.svn-base215
1 files changed, 215 insertions, 0 deletions
diff --git a/src/libopkg/.svn/text-base/hash_table.c.svn-base b/src/libopkg/.svn/text-base/hash_table.c.svn-base
new file mode 100644
index 0000000..37b53e9
--- /dev/null
+++ b/src/libopkg/.svn/text-base/hash_table.c.svn-base
@@ -0,0 +1,215 @@
+/* hash.c - hash tables for opkg
+
+ Steven M. Ayer, Jamey Hicks
+
+ Copyright (C) 2002 Compaq Computer Corporation
+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2, or (at
+ your option) any later version.
+
+ This program is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "hash_table.h"
+#include "opkg_message.h"
+#include "libbb/libbb.h"
+
+
+static unsigned long
+djb2_hash(const unsigned char *str)
+{
+ unsigned long hash = 5381;
+ int c;
+ while ((c = *str++))
+ hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
+ return hash;
+}
+
+static int
+hash_index(hash_table_t *hash, const char *key)
+{
+ return djb2_hash((const unsigned char *)key) % hash->n_buckets;
+}
+
+/*
+ * this is an open table keyed by strings
+ */
+void
+hash_table_init(const char *name, hash_table_t *hash, int len)
+{
+ if (hash->entries != NULL) {
+ opkg_msg(ERROR, "Internal error: non empty hash table.\n");
+ return;
+ }
+
+ memset(hash, 0, sizeof(hash_table_t));
+
+ hash->name = name;
+ hash->n_buckets = len;
+ hash->entries = xcalloc(hash->n_buckets, sizeof(hash_entry_t));
+}
+
+void
+hash_print_stats(hash_table_t *hash)
+{
+ printf("hash_table: %s, %d bytes\n"
+ "\tn_buckets=%d, n_elements=%d, n_collisions=%d\n"
+ "\tmax_bucket_len=%d, n_used_buckets=%d, ave_bucket_len=%.2f\n"
+ "\tn_hits=%d, n_misses=%d\n",
+ hash->name,
+ hash->n_buckets*(int)sizeof(hash_entry_t),
+ hash->n_buckets,
+ hash->n_elements,
+ hash->n_collisions,
+ hash->max_bucket_len,
+ hash->n_used_buckets,
+ (hash->n_used_buckets ?
+ ((float)hash->n_elements)/hash->n_used_buckets : 0.0f),
+ hash->n_hits,
+ hash->n_misses);
+}
+
+void hash_table_deinit(hash_table_t *hash)
+{
+ int i;
+ if (!hash)
+ return;
+
+ /* free the reminaing entries */
+ for (i = 0; i < hash->n_buckets; i++) {
+ hash_entry_t *hash_entry = (hash->entries + i);
+ free (hash_entry->key);
+ /* skip the first entry as this is part of the array */
+ hash_entry = hash_entry->next;
+ while (hash_entry)
+ {
+ hash_entry_t *old = hash_entry;
+ hash_entry = hash_entry->next;
+ free (old->key);
+ free (old);
+ }
+ }
+
+ free (hash->entries);
+
+ hash->entries = NULL;
+ hash->n_buckets = 0;
+}
+
+void *hash_table_get(hash_table_t *hash, const char *key)
+{
+ int ndx= hash_index(hash, key);
+ hash_entry_t *hash_entry = hash->entries + ndx;
+ while (hash_entry)
+ {
+ if (hash_entry->key)
+ {
+ if (strcmp(key, hash_entry->key) == 0) {
+ hash->n_hits++;
+ return hash_entry->data;
+ }
+ }
+ hash_entry = hash_entry->next;
+ }
+ hash->n_misses++;
+ return NULL;
+}
+
+int hash_table_insert(hash_table_t *hash, const char *key, void *value)
+{
+ int bucket_len = 0;
+ int ndx= hash_index(hash, key);
+ hash_entry_t *hash_entry = hash->entries + ndx;
+ if (hash_entry->key) {
+ if (strcmp(hash_entry->key, key) == 0) {
+ /* alread in table, update the value */
+ hash_entry->data = value;
+ return 0;
+ } else {
+ /*
+ * if this is a collision, we have to go to the end of the ll,
+ * then add a new entry
+ * before we can hook up the value
+ */
+ while (hash_entry->next) {
+ hash_entry = hash_entry->next;
+ if (strcmp(hash_entry->key, key) == 0) {
+ hash_entry->data = value;
+ return 0;
+ }
+ bucket_len++;
+ }
+ hash_entry->next = xcalloc(1, sizeof(hash_entry_t));
+ hash_entry = hash_entry->next;
+ hash_entry->next = NULL;
+
+ hash->n_collisions++;
+ if (++bucket_len > hash->max_bucket_len)
+ hash->max_bucket_len = bucket_len;
+ }
+ } else
+ hash->n_used_buckets++;
+
+ hash->n_elements++;
+ hash_entry->key = xstrdup(key);
+ hash_entry->data = value;
+
+ return 0;
+}
+
+int hash_table_remove(hash_table_t *hash, const char *key)
+{
+ int ndx= hash_index(hash, key);
+ hash_entry_t *hash_entry = hash->entries + ndx;
+ hash_entry_t *next_entry=NULL, *last_entry=NULL;
+ while (hash_entry)
+ {
+ if (hash_entry->key)
+ {
+ if (strcmp(key, hash_entry->key) == 0) {
+ free(hash_entry->key);
+ if (last_entry) {
+ last_entry->next = hash_entry->next;
+ free(hash_entry);
+ } else {
+ next_entry = hash_entry->next;
+ if (next_entry) {
+ memmove(hash_entry, next_entry, sizeof(hash_entry_t));
+ free(next_entry);
+ } else {
+ memset(hash_entry, 0 , sizeof(hash_entry_t));
+ }
+ }
+ return 1;
+ }
+ }
+ last_entry = hash_entry;
+ hash_entry = hash_entry->next;
+ }
+ return 0;
+}
+
+void hash_table_foreach(hash_table_t *hash, void (*f)(const char *key, void *entry, void *data), void *data)
+{
+ int i;
+ if (!hash || !f)
+ return;
+
+ for (i = 0; i < hash->n_buckets; i++) {
+ hash_entry_t *hash_entry = (hash->entries + i);
+ do {
+ if(hash_entry->key) {
+ f(hash_entry->key, hash_entry->data, data);
+ }
+ } while((hash_entry = hash_entry->next));
+ }
+}
+