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/*
This file is part of GNUnet.
Copyright (C) 2010 GNUnet e.V.
GNUnet is free software: you can redistribute it and/or modify it
under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License,
or (at your option) any later version.
GNUnet 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
Affero General Public License for more details.
*/
/**
* @author Christian Grothoff
*
* @file
* Library for creating block groups (to be used by block plugins)
*
* @defgroup block Block group library
* Library for data group management
* @{
*/
#ifndef GNUNET_BLOCK_GROUP_LIB_H
#define GNUNET_BLOCK_GROUP_LIB_H
#include "gnunet_util_lib.h"
#include "gnunet_block_lib.h"
#ifdef __cplusplus
extern "C"
{
#if 0 /* keep Emacsens' auto-indent happy */
}
#endif
#endif
/**
* How many bytes should a bloomfilter be if we have already seen
* entry_count responses? Sized so that do not have to
* re-size the filter too often (to keep it cheap).
*
* Since other peers will also add entries but not resize the filter,
* we should generally pick a slightly larger size than what the
* strict math would suggest.
*
* @param entry_count expected number of entries in the Bloom filter
* @param k number of bits set per entry
* @return must be a power of two and smaller or equal to 2^15.
*/
size_t
GNUNET_BLOCK_GROUP_compute_bloomfilter_size (unsigned int entry_count,
unsigned int k);
/**
* Create a new block group that filters duplicates using a Bloom filter.
*
* @param ctx block context in which the block group is created
* @param bf_size size of the Bloom filter
* @param bf_k K-value for the Bloom filter
* @param type block type
* @param nonce random value used to seed the group creation
* @param raw_data optional serialized prior state of the group, NULL if unavailable/fresh
* @param raw_data_size number of bytes in @a raw_data, 0 if unavailable/fresh
* @return block group handle, NULL if block groups are not supported
* by this @a type of block (this is not an error)
*/
struct GNUNET_BLOCK_Group *
GNUNET_BLOCK_GROUP_bf_create (void *cls,
size_t bf_size,
unsigned int bf_k,
enum GNUNET_BLOCK_Type type,
uint32_t nonce,
const void *raw_data,
size_t raw_data_size);
/**
* Test if @a hc is contained in the Bloom filter of @a bg. If so,
* return #GNUNET_YES. If not, add @a hc to the Bloom filter and
* return #GNUNET_NO.
*
* @param bg block group to use for testing
* @param hc hash of element to evaluate
* @return #GNUNET_YES if @a hc is (likely) a duplicate
* #GNUNET_NO if @a hc was definitively not in @bg (but now is)
*/
int
GNUNET_BLOCK_GROUP_bf_test_and_set (struct GNUNET_BLOCK_Group *bg,
const struct GNUNET_HashCode *hc);
#if 0 /* keep Emacsens' auto-indent happy */
{
#endif
#ifdef __cplusplus
}
#endif
/* ifndef GNUNET_BLOCK_GROUP_LIB_H */
#endif
/** @} */ /* end of group */
/* end of gnunet_block_group_lib.h */
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