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- /*
- This file is part of GNUnet
- Copyright (C) 2012, 2013 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.
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @file regex/regex_internal_lib.h
- * @brief library to parse regular expressions into dfa
- * @author Maximilian Szengel
- */
- #ifndef REGEX_INTERNAL_LIB_H
- #define REGEX_INTERNAL_LIB_H
- #include "gnunet_util_lib.h"
- #include "gnunet_dht_service.h"
- #include "gnunet_statistics_service.h"
- #include "regex_block_lib.h"
- #ifdef __cplusplus
- extern "C"
- {
- #if 0 /* keep Emacsens' auto-indent happy */
- }
- #endif
- #endif
- /**
- * Automaton (NFA/DFA) representation.
- */
- struct REGEX_INTERNAL_Automaton;
- /**
- * Construct DFA for the given 'regex' of length 'len'.
- *
- * Path compression means, that for example a DFA o -> a -> b -> c -> o will be
- * compressed to o -> abc -> o. Note that this parameter influences the
- * non-determinism of states of the resulting NFA in the DHT (number of outgoing
- * edges with the same label). For example for an application that stores IPv4
- * addresses as bitstrings it could make sense to limit the path compression to
- * 4 or 8.
- *
- * @param regex regular expression string.
- * @param len length of the regular expression.
- * @param max_path_len limit the path compression length to the
- * given value. If set to 1, no path compression is applied. Set to 0 for
- * maximal possible path compression (generally not desireable).
- * @return DFA, needs to be freed using #REGEX_INTERNAL_automaton_destroy().
- */
- struct REGEX_INTERNAL_Automaton *
- REGEX_INTERNAL_construct_dfa (const char *regex,
- const size_t len,
- unsigned int max_path_len);
- /**
- * Free the memory allocated by constructing the REGEX_INTERNAL_Automaton.
- * data structure.
- *
- * @param a automaton to be destroyed.
- */
- void
- REGEX_INTERNAL_automaton_destroy (struct REGEX_INTERNAL_Automaton *a);
- /**
- * Evaluates the given 'string' against the given compiled regex.
- *
- * @param a automaton.
- * @param string string to check.
- *
- * @return 0 if string matches, non 0 otherwise.
- */
- int
- REGEX_INTERNAL_eval (struct REGEX_INTERNAL_Automaton *a,
- const char *string);
- /**
- * Get the first key for the given @a input_string. This hashes
- * the first x bits of the @a input_string.
- *
- * @param input_string string.
- * @param string_len length of the @a input_string.
- * @param key pointer to where to write the hash code.
- * @return number of bits of @a input_string that have been consumed
- * to construct the key
- */
- size_t
- REGEX_INTERNAL_get_first_key (const char *input_string,
- size_t string_len,
- struct GNUNET_HashCode *key);
- /**
- * Iterator callback function.
- *
- * @param cls closure.
- * @param key hash for current state.
- * @param proof proof for current state
- * @param accepting #GNUNET_YES if this is an accepting state, #GNUNET_NO if not.
- * @param num_edges number of edges leaving current state.
- * @param edges edges leaving current state.
- */
- typedef void
- (*REGEX_INTERNAL_KeyIterator)(void *cls,
- const struct GNUNET_HashCode *key,
- const char *proof,
- int accepting,
- unsigned int num_edges,
- const struct REGEX_BLOCK_Edge *edges);
- /**
- * Iterate over all edges starting from start state of automaton 'a'. Calling
- * iterator for each edge.
- *
- * @param a automaton.
- * @param iterator iterator called for each edge.
- * @param iterator_cls closure.
- */
- void
- REGEX_INTERNAL_iterate_all_edges (struct REGEX_INTERNAL_Automaton *a,
- REGEX_INTERNAL_KeyIterator iterator,
- void *iterator_cls);
- /**
- * Iterate over all edges of automaton 'a' that are reachable from a state with
- * a proof of at least #GNUNET_REGEX_INITIAL_BYTES characters.
- *
- * Call the iterator for each such edge.
- *
- * @param a automaton.
- * @param iterator iterator called for each reachable edge.
- * @param iterator_cls closure.
- */
- void
- REGEX_INTERNAL_iterate_reachable_edges (struct REGEX_INTERNAL_Automaton *a,
- REGEX_INTERNAL_KeyIterator iterator,
- void *iterator_cls);
- /**
- * Handle to store cached data about a regex announce.
- */
- struct REGEX_INTERNAL_Announcement;
- /**
- * Handle to store data about a regex search.
- */
- struct REGEX_INTERNAL_Search;
- /**
- * Announce a regular expression: put all states of the automaton in the DHT.
- * Does not free resources, must call #REGEX_INTERNAL_announce_cancel() for that.
- *
- * @param dht An existing and valid DHT service handle. CANNOT be NULL.
- * @param priv our private key, must remain valid until the announcement is cancelled
- * @param regex Regular expression to announce.
- * @param compression How many characters per edge can we squeeze?
- * @param stats Optional statistics handle to report usage. Can be NULL.
- * @return Handle to reuse o free cached resources.
- * Must be freed by calling #REGEX_INTERNAL_announce_cancel().
- */
- struct REGEX_INTERNAL_Announcement *
- REGEX_INTERNAL_announce (struct GNUNET_DHT_Handle *dht,
- const struct GNUNET_CRYPTO_EddsaPrivateKey *priv,
- const char *regex,
- uint16_t compression,
- struct GNUNET_STATISTICS_Handle *stats);
- /**
- * Announce again a regular expression previously announced.
- * Does use caching to speed up process.
- *
- * @param h Handle returned by a previous #REGEX_INTERNAL_announce() call.
- */
- void
- REGEX_INTERNAL_reannounce (struct REGEX_INTERNAL_Announcement *h);
- /**
- * Clear all cached data used by a regex announce.
- * Does not close DHT connection.
- *
- * @param h Handle returned by a previous #REGEX_INTERNAL_announce() call.
- */
- void
- REGEX_INTERNAL_announce_cancel (struct REGEX_INTERNAL_Announcement *h);
- /**
- * Search callback function.
- *
- * @param cls Closure provided in #REGEX_INTERNAL_search().
- * @param id Peer providing a regex that matches the string.
- * @param get_path Path of the get request.
- * @param get_path_length Length of @a get_path.
- * @param put_path Path of the put request.
- * @param put_path_length Length of the @a put_path.
- */
- typedef void
- (*REGEX_INTERNAL_Found)(void *cls,
- const struct GNUNET_PeerIdentity *id,
- const struct GNUNET_PeerIdentity *get_path,
- unsigned int get_path_length,
- const struct GNUNET_PeerIdentity *put_path,
- unsigned int put_path_length);
- /**
- * Search for a peer offering a regex matching certain string in the DHT.
- * The search runs until #REGEX_INTERNAL_search_cancel() is called, even if results
- * are returned.
- *
- * @param dht An existing and valid DHT service handle.
- * @param string String to match against the regexes in the DHT.
- * @param callback Callback for found peers.
- * @param callback_cls Closure for @c callback.
- * @param stats Optional statistics handle to report usage. Can be NULL.
- * @return Handle to stop search and free resources.
- * Must be freed by calling #REGEX_INTERNAL_search_cancel().
- */
- struct REGEX_INTERNAL_Search *
- REGEX_INTERNAL_search (struct GNUNET_DHT_Handle *dht,
- const char *string,
- REGEX_INTERNAL_Found callback,
- void *callback_cls,
- struct GNUNET_STATISTICS_Handle *stats);
- /**
- * Stop search and free all data used by a #REGEX_INTERNAL_search() call.
- * Does not close DHT connection.
- *
- * @param h Handle returned by a previous #REGEX_INTERNAL_search() call.
- */
- void
- REGEX_INTERNAL_search_cancel (struct REGEX_INTERNAL_Search *h);
- #if 0 /* keep Emacsens' auto-indent happy */
- {
- #endif
- #ifdef __cplusplus
- }
- #endif
- /* end of regex_internal_lib.h */
- #endif
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