Initial commit of Hyperscan

src/nfagraph/ng_stop.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2015, Intel Corporation
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *  * Neither the name of Intel Corporation nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file
+ * \brief Stop Alphabet calculation.
+ */
+
+#ifndef NG_STOP_H
+#define NG_STOP_H
+
+#include "ue2common.h"
+#include "som/som.h"
+
+#include <vector>
+
+namespace ue2 {
+
+struct CastleProto;
+class CharReach;
+class NGHolder;
+
+/** Find the set of characters that are not present in the reachability of
+ * graph \p g after a certain depth (currently 8). If a character in this set
+ * is encountered, it means that the NFA is either dead or has not progressed
+ * more than 8 characters from its start states. */
+CharReach findStopAlphabet(const NGHolder &g, som_type som);
+
+/** Calculate the stop alphabet for each depth from 0 to MAX_STOP_DEPTH. Then
+ * build an eight-bit mask per character C, with each bit representing the
+ * depth before the location of character C (if encountered) that the NFA would
+ * be in a predictable start state. */
+std::vector<u8> findLeftOffsetStopAlphabet(const NGHolder &g, som_type som);
+std::vector<u8> findLeftOffsetStopAlphabet(const CastleProto &c, som_type som);
+
+} // namespace ue2
+
+#endif