*/
/**
* @file src/regex/regex_internal.h
- * @brief common internal definitions for regex library
+ * @brief common internal definitions for regex library.
* @author Maximilian Szengel
*/
#ifndef REGEX_INTERNAL_H
/**
- * Transition between two states. Each state can have 0-n transitions. If label
- * is 0, this is considered to be an epsilon transition.
+ * Transition between two states. Transitions are stored at the states from
+ * which they origin ('from_state'). Each state can have 0-n transitions.
+ * If label is NULL, this is considered to be an epsilon transition.
*/
struct GNUNET_REGEX_Transition
{
};
+/**
+ * A state. Can be used in DFA and NFA automatons.
+ */
+struct GNUNET_REGEX_State;
+
+
+/**
+ * Set of states.
+ */
+struct GNUNET_REGEX_StateSet
+{
+ /**
+ * Array of states.
+ */
+ struct GNUNET_REGEX_State **states;
+
+ /**
+ * Number of entries in *use* in the 'states' array.
+ */
+ unsigned int off;
+
+ /**
+ * Length of the 'states' array.
+ */
+ unsigned int size;
+};
+
+
/**
* A state. Can be used in DFA and NFA automatons.
*/
struct GNUNET_REGEX_State
{
/**
- * This is a linked list.
+ * This is a linked list to keep states in an automaton.
*/
struct GNUNET_REGEX_State *prev;
/**
- * This is a linked list.
+ * This is a linked list to keep states in an automaton.
*/
struct GNUNET_REGEX_State *next;
+ /**
+ * This is a multi DLL for StateSet_MDLL.
+ */
+ struct GNUNET_REGEX_State *prev_SS;
+
+ /**
+ * This is a multi DLL for StateSet_MDLL.
+ */
+ struct GNUNET_REGEX_State *next_SS;
+
+ /**
+ * This is a multi DLL for StateSet_MDLL Stack.
+ */
+ struct GNUNET_REGEX_State *prev_ST;
+
+ /**
+ * This is a multi DLL for StateSet_MDLL Stack.
+ */
+ struct GNUNET_REGEX_State *next_ST;
+
/**
* Unique state id.
*/
/**
* Marking the state as contained. This is used for checking, if the state is
- * contained in a set in constant time
+ * contained in a set in constant time.
*/
int contained;
int lowlink;
/**
- * Human readable name of the automaton. Used for debugging and graph
+ * Human readable name of the state. Used for debugging and graph
* creation.
*/
char *name;
*/
struct GNUNET_REGEX_Transition *transitions_tail;
+ /**
+ * Number of incoming transitions. Used for compressing DFA paths.
+ */
+ unsigned int incoming_transition_count;
+
/**
* Set of states on which this state is based on. Used when creating a DFA out
* of several NFA states.
*/
- struct GNUNET_REGEX_StateSet *nfa_set;
+ struct GNUNET_REGEX_StateSet nfa_set;
};
* Canonical regex (result of RX->NFA->DFA->RX)
*/
char *canonical_regex;
+
+ /**
+ * GNUNET_YES, if multi strides have been added to the Automaton.
+ */
+ int is_multistrided;
};
+/**
+ * Construct an NFA by parsing the regex string of length 'len'.
+ *
+ * @param regex regular expression string.
+ * @param len length of the string.
+ *
+ * @return NFA, needs to be freed using GNUNET_REGEX_automaton_destroy.
+ */
+struct GNUNET_REGEX_Automaton *
+GNUNET_REGEX_construct_nfa (const char *regex, const size_t len);
+
+
+/**
+ * Function that get's passed to automaton traversal and is called before each
+ * next traversal from state 's' using transition 't' to check if traversal
+ * should proceed. Return GNUNET_NO to stop traversal or GNUNET_YES to continue.
+ *
+ * @param cls closure for the check.
+ * @param s current state in the traversal.
+ * @param t current transition from state 's' that will be used for the next
+ * step.
+ *
+ * @return GNUNET_YES to proceed traversal, GNUNET_NO to stop.
+ */
+typedef int (*GNUNET_REGEX_traverse_check) (void *cls,
+ struct GNUNET_REGEX_State * s,
+ struct GNUNET_REGEX_Transition * t);
+
+
/**
* Function that is called with each state, when traversing an automaton.
*
*
* @param a automaton to be traversed.
* @param start start state, pass a->start or NULL to traverse the whole automaton.
+ * @param check function that is checked before advancing on each transition
+ * in the DFS.
+ * @param check_cls closure for check.
* @param action action to be performed on each state.
* @param action_cls closure for action
*/
void
GNUNET_REGEX_automaton_traverse (const struct GNUNET_REGEX_Automaton *a,
struct GNUNET_REGEX_State *start,
+ GNUNET_REGEX_traverse_check check,
+ void *check_cls,
GNUNET_REGEX_traverse_action action,
void *action_cls);
-
/**
* Get the canonical regex of the given automaton.
* When constructing the automaton a proof is computed for each state,
*
* @param a automaton for which the canonical regex should be returned.
*
- * @return
+ * @return canonical regex string.
*/
const char *
GNUNET_REGEX_get_canonical_regex (struct GNUNET_REGEX_Automaton *a);
+/**
+ * Get the number of transitions that are contained in the given automaton.
+ *
+ * @param a automaton for which the number of transitions should be returned.
+ *
+ * @return number of transitions in the given automaton.
+ */
+unsigned int
+GNUNET_REGEX_get_transition_count (struct GNUNET_REGEX_Automaton *a);
+
+
+/**
+ * Context that contains an id counter for states and transitions as well as a
+ * DLL of automatons used as a stack for NFA construction.
+ */
+struct GNUNET_REGEX_Context
+{
+ /**
+ * Unique state id.
+ */
+ unsigned int state_id;
+
+ /**
+ * Unique transition id.
+ */
+ unsigned int transition_id;
+
+ /**
+ * DLL of GNUNET_REGEX_Automaton's used as a stack.
+ */
+ struct GNUNET_REGEX_Automaton *stack_head;
+
+ /**
+ * DLL of GNUNET_REGEX_Automaton's used as a stack.
+ */
+ struct GNUNET_REGEX_Automaton *stack_tail;
+};
+
+
+/**
+ * Adds multi-strided transitions to the given 'dfa'.
+ *
+ * @param regex_ctx regex context needed to add transitions to the automaton.
+ * @param dfa DFA to which the multi strided transitions should be added.
+ * @param stride_len length of the strides.
+ */
+void
+GNUNET_REGEX_dfa_add_multi_strides (struct GNUNET_REGEX_Context *regex_ctx,
+ struct GNUNET_REGEX_Automaton *dfa,
+ const unsigned int stride_len);
+
+
/**
* Generate a (pseudo) random regular expression of length 'rx_length', as well
* as a (optional) string that will be matched by the generated regex. The