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diff --git a/src/regex/regex_internal_lib.h b/src/regex/regex_internal_lib.h
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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/>.
+*/
+/**
+ * @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