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diff --git a/pjlib/include/pj/hash.h b/pjlib/include/pj/hash.h
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+/* $Header: /pjproject-0.3/pjlib/include/pj/hash.h 6     10/14/05 12:26a Bennylp $ */
+
+#ifndef __PJ_HASH_H__
+#define __PJ_HASH_H__
+
+/**
+ * @file hash.h
+ * @brief Hash Table.
+ */
+
+#include <pj/types.h>
+
+PJ_BEGIN_DECL
+
+/**
+ * @defgroup PJ_HASH Hash Table
+ * @ingroup PJ_DS
+ * @{
+ * A hash table is a dictionary in which keys are mapped to array positions by
+ * hash functions. Having the keys of more than one item map to the same 
+ * position is called a collision. In this library, we will chain the nodes
+ * that have the same key in a list.
+ */
+
+/**
+ * If this constant is used as keylen, then the key is interpreted as
+ * NULL terminated string.
+ */
+#define PJ_HASH_KEY_STRING	((unsigned)-1)
+
+/**
+ * This is the function that is used by the hash table to calculate hash value
+ * of the specified key.
+ *
+ * @param hval	    the initial hash value, or zero.
+ * @param key	    the key to calculate.
+ * @param keylen    the length of the key, or PJ_HASH_KEY_STRING to treat 
+ *		    the key as null terminated string.
+ *
+ * @return          the hash value.
+ */
+PJ_DECL(pj_uint32_t) pj_hash_calc(pj_uint32_t hval, 
+				  const void *key, unsigned keylen);
+
+
+/**
+ * Create a hash table with the specified 'bucket' size.
+ *
+ * @param pool	the pool from which the hash table will be allocated from.
+ * @param size	the bucket size, which will be round-up to the nearest 2^n+1
+ *
+ * @return the hash table.
+ */
+PJ_DECL(pj_hash_table_t*) pj_hash_create(pj_pool_t *pool, unsigned size);
+
+
+/**
+ * Get the value associated with the specified key.
+ *
+ * @param ht	    the hash table.
+ * @param key	    the key to look for.
+ * @param keylen    the length of the key, or PJ_HASH_KEY_STRING to use the
+ *		    string length of the key.
+ *
+ * @return the value associated with the key, or NULL if the key is not found.
+ */
+PJ_DECL(void *) pj_hash_get( pj_hash_table_t *ht,
+			     const void *key, unsigned keylen );
+
+
+/**
+ * Associate/disassociate a value with the specified key.
+ *
+ * @param pool	    the pool to allocate the new entry if a new entry has to be
+ *		    created.
+ * @param ht	    the hash table.
+ * @param key	    the key.
+ * @param keylen    the length of the key, or PJ_HASH_KEY_STRING to use the 
+ *		    string length of the key.
+ * @param value	    value to be associated, or NULL to delete the entry with
+ *		    the specified key.
+ */
+PJ_DECL(void) pj_hash_set( pj_pool_t *pool, pj_hash_table_t *ht,
+			   const void *key, unsigned keylen,
+			   void *value );
+
+/**
+ * Get the total number of entries in the hash table.
+ *
+ * @param ht	the hash table.
+ *
+ * @return the number of entries in the hash table.
+ */
+PJ_DECL(unsigned) pj_hash_count( pj_hash_table_t *ht );
+
+
+/**
+ * Get the iterator to the first element in the hash table. 
+ *
+ * @param ht	the hash table.
+ * @param it	the iterator for iterating hash elements.
+ *
+ * @return the iterator to the hash element, or NULL if no element presents.
+ */
+PJ_DECL(pj_hash_iterator_t*) pj_hash_first( pj_hash_table_t *ht,
+					    pj_hash_iterator_t *it );
+
+
+/**
+ * Get the next element from the iterator.
+ *
+ * @param ht	the hash table.
+ * @param it	the hash iterator.
+ *
+ * @return the next iterator, or NULL if there's no more element.
+ */
+PJ_DECL(pj_hash_iterator_t*) pj_hash_next( pj_hash_table_t *ht, 
+					   pj_hash_iterator_t *it );
+
+/**
+ * Get the value associated with a hash iterator.
+ *
+ * @param ht	the hash table.
+ * @param it	the hash iterator.
+ *
+ * @return the value associated with the current element in iterator.
+ */
+PJ_DECL(void*) pj_hash_this( pj_hash_table_t *ht,
+			     pj_hash_iterator_t *it );
+
+
+/**
+ * @}
+ */
+
+PJ_END_DECL
+
+#endif
+
+