ssp_items.h

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/* Copyright 2005 Ben Hyde
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/** \file ssp_items.h
 * \brief Item abstraction
 *
 * The bloom filter and counter work on sets or streams of items.
 * Items are represented by data of type \c void \c * and the
 * only operation on those are hash functions.
 */

#ifndef SSP_ITEMS_S 
#define SSP_ITEMS_S 

#include <apr.h>

/** \brief Signature for user provided hash functions.
 *
 * The type ssp_hash_function_t defines the signature of
 * of the two hash functions the user must provide on his
 * items.  They take a items, represented by a void *
 * pointer, and return up to 32 bits of psuedo random hash
 * derived from the item.  If fewer bits are needed in
 * the filter/counters you instantiate only the low order
 * bits are used.  Of course, in that scenario the user's
 * hash functions  need not create more hash bits.
 */
typedef apr_uint32_t (ssp_hash_function_t)(void *item);

#endif /* SSP_ITEMS_S  */

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