diff options
Diffstat (limited to 'pjlib/src/pj/hash.c')
| -rw-r--r-- | pjlib/src/pj/hash.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/pjlib/src/pj/hash.c b/pjlib/src/pj/hash.c new file mode 100644 index 00000000..01bfaa6b --- /dev/null +++ b/pjlib/src/pj/hash.c @@ -0,0 +1,252 @@ +/* $Header: /pjproject-0.3/pjlib/src/pj/hash.c 8 10/14/05 12:26a Bennylp $ */
+/* $Log: /pjproject-0.3/pjlib/src/pj/hash.c $
+ *
+ * 8 10/14/05 12:26a Bennylp
+ * Finished error code framework, some fixes in ioqueue, etc. Pretty
+ * major.
+ *
+ * 7 9/17/05 10:37a Bennylp
+ * Major reorganization towards version 0.3.
+ *
+ */
+#include <pj/hash.h>
+#include <pj/log.h>
+#include <pj/string.h>
+#include <pj/pool.h>
+#include <pj/os.h>
+
+/**
+ * The hash multiplier used to calculate hash value.
+ */
+#define PJ_HASH_MULTIPLIER 33
+
+
+struct pj_hash_entry
+{
+ struct pj_hash_entry *next;
+ const void *key;
+ pj_uint32_t hash;
+ pj_uint32_t keylen;
+ void *value;
+};
+
+
+struct pj_hash_table_t
+{
+ pj_hash_entry **table;
+ unsigned count, rows;
+ pj_hash_iterator_t iterator;
+};
+
+
+
+PJ_DEF(pj_uint32_t) pj_hash_calc(pj_uint32_t hash, const void *key, unsigned keylen)
+{
+ PJ_CHECK_STACK();
+
+ if (keylen==PJ_HASH_KEY_STRING) {
+ const unsigned char *p = key;
+ for ( ; *p; ++p ) {
+ hash = hash * PJ_HASH_MULTIPLIER + *p;
+ }
+ keylen = p - (const unsigned char*)key;
+ } else {
+ const unsigned char *p = key,
+ *end = p + keylen;
+ for ( ; p!=end; ++p) {
+ hash = hash * PJ_HASH_MULTIPLIER + *p;
+ }
+ }
+ return hash;
+}
+
+
+PJ_DEF(pj_hash_table_t*) pj_hash_create(pj_pool_t *pool, unsigned size)
+{
+ pj_hash_table_t *h;
+ unsigned table_size;
+
+ h = pj_pool_alloc(pool, sizeof(pj_hash_table_t));
+ h->count = 0;
+
+ PJ_LOG( 5, ("hashtbl", "hash table %p created from pool %s", h, pj_pool_getobjname(pool)));
+
+ /* size must be 2^n - 1.
+ round-up the size to this rule, except when size is 2^n, then size
+ will be round-down to 2^n-1.
+ */
+ table_size = 8;
+ do {
+ table_size <<= 1;
+ } while (table_size <= size);
+ table_size -= 1;
+
+ h->rows = table_size;
+ h->table = pj_pool_calloc(pool, table_size+1, sizeof(pj_hash_entry*));
+ return h;
+}
+
+static pj_hash_entry **find_entry( pj_pool_t *pool, pj_hash_table_t *ht,
+ const void *key, unsigned keylen,
+ void *val)
+{
+ pj_uint32_t hash;
+ pj_hash_entry **p_entry, *entry;
+
+ hash=0;
+ if (keylen==PJ_HASH_KEY_STRING) {
+ const unsigned char *p = key;
+ for ( ; *p; ++p ) {
+ hash = hash * PJ_HASH_MULTIPLIER + *p;
+ }
+ keylen = p - (const unsigned char*)key;
+ } else {
+ const unsigned char *p = key,
+ *end = p + keylen;
+ for ( ; p!=end; ++p) {
+ hash = hash * PJ_HASH_MULTIPLIER + *p;
+ }
+ }
+
+ /* scan the linked list */
+ for (p_entry = &ht->table[hash & ht->rows], entry=*p_entry;
+ entry;
+ p_entry = &entry->next, entry = *p_entry)
+ {
+ if (entry->hash==hash && entry->keylen==keylen &&
+ memcmp(entry->key, key, keylen)==0)
+ {
+ break;
+ }
+ }
+
+ if (entry || val==NULL)
+ return p_entry;
+
+ /* create a new entry */
+ entry = pj_pool_alloc(pool, sizeof(pj_hash_entry));
+ PJ_LOG(5, ("hashtbl", "%p: New p_entry %p created, pool used=%u, cap=%u", ht, entry,
+ pj_pool_get_used_size(pool), pj_pool_get_capacity(pool)));
+ entry->next = NULL;
+ entry->hash = hash;
+ entry->key = key;
+ entry->keylen = keylen;
+ entry->value = val;
+ *p_entry = entry;
+
+ ++ht->count;
+
+ return p_entry;
+}
+
+PJ_DEF(void *) pj_hash_get( pj_hash_table_t *ht,
+ const void *key, unsigned keylen )
+{
+ pj_hash_entry *entry;
+ entry = *find_entry( NULL, ht, key, keylen, NULL);
+ return entry ? entry->value : NULL;
+}
+
+PJ_DEF(void) pj_hash_set( pj_pool_t *pool, pj_hash_table_t *ht,
+ const void *key, unsigned keylen,
+ void *value )
+{
+ pj_hash_entry **p_entry;
+
+ p_entry = find_entry( pool, ht, key, keylen, value );
+ if (*p_entry) {
+ if (value == NULL) {
+ /* delete entry */
+ PJ_LOG(5, ("hashtbl", "%p: p_entry %p deleted", ht, *p_entry));
+ *p_entry = (*p_entry)->next;
+ --ht->count;
+
+ } else {
+ /* overwrite */
+ (*p_entry)->value = value;
+ PJ_LOG(5, ("hashtbl", "%p: p_entry %p value set to %p", ht, *p_entry, value));
+ }
+ }
+}
+
+PJ_DEF(unsigned) pj_hash_count( pj_hash_table_t *ht )
+{
+ return ht->count;
+}
+
+PJ_DEF(pj_hash_iterator_t*) pj_hash_first( pj_hash_table_t *ht,
+ pj_hash_iterator_t *it )
+{
+ it->index = 0;
+ it->entry = NULL;
+
+ for (; it->index < ht->rows; ++it->index) {
+ it->entry = ht->table[it->index];
+ if (it->entry) {
+ break;
+ }
+ }
+
+ return it->entry ? it : NULL;
+}
+
+PJ_DEF(pj_hash_iterator_t*) pj_hash_next( pj_hash_table_t *ht,
+ pj_hash_iterator_t *it )
+{
+ it->entry = it->entry->next;
+ if (it->entry) {
+ return it;
+ }
+
+ for (++it->index; it->index < ht->rows; ++it->index) {
+ it->entry = ht->table[it->index];
+ if (it->entry) {
+ break;
+ }
+ }
+
+ return it->entry ? it : NULL;
+}
+
+PJ_DEF(void*) pj_hash_this( pj_hash_table_t *ht, pj_hash_iterator_t *it )
+{
+ PJ_CHECK_STACK();
+ PJ_UNUSED_ARG(ht);
+ return it->entry->value;
+}
+
+#if 0
+void pj_hash_dump_collision( pj_hash_table_t *ht )
+{
+ unsigned min=0xFFFFFFFF, max=0;
+ unsigned i;
+ char line[120];
+ int len, totlen = 0;
+
+ for (i=0; i<ht->rows; ++i) {
+ unsigned count = 0;
+ pj_hash_entry *entry = ht->table[i];
+ while (entry) {
+ ++count;
+ entry = entry->next;
+ }
+ if (count < min)
+ min = count;
+ if (count > max)
+ max = count;
+ len = pj_snprintf( line+totlen, sizeof(line)-totlen, "%3d:%3d ", i, count);
+ if (len < 1)
+ break;
+ totlen += len;
+
+ if ((i+1) % 10 == 0) {
+ line[totlen] = '\0';
+ PJ_LOG(4,(__FILE__, line));
+ }
+ }
+
+ PJ_LOG(4,(__FILE__,"Count: %d, min: %d, max: %d\n", ht->count, min, max));
+}
+#endif
+
+
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