Initial commit of Hyperscan

src/nfagraph/ng_som_util.h

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+/*
+ * 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 Utility functions related to SOM ("Start of Match").
+ */
+
+#ifndef NG_SOM_UTIL_H
+#define NG_SOM_UTIL_H
+
+#include "ng_util.h"
+#include "util/depth.h"
+#include "util/ue2_containers.h"
+
+#include <map>
+#include <vector>
+
+namespace ue2 {
+
+class NGHolder;
+
+/**
+ * Returns min/max distance from start of match, index by vertex_id.
+ */
+std::vector<DepthMinMax> getDistancesFromSOM(const NGHolder &g);
+
+/**
+ * Returns true if the first match by end-offset must always be the first match
+ * by start-offset.
+ */
+bool firstMatchIsFirst(const NGHolder &p);
+
+struct smgb_cache : public mbsb_cache {
+    explicit smgb_cache(const NGHolder &gg) : mbsb_cache(gg) {}
+    std::map<NFAVertex, bool> smgb;
+};
+
+bool somMayGoBackwards(NFAVertex u, const NGHolder &g,
+                       const ue2::unordered_map<NFAVertex, u32> &region_map,
+                       smgb_cache &cache);
+
+/**
+ * Returns true if matching 'sent' causes all tail states in the main graph \a
+ * g to go dead. A tail state is any state with a region greater than
+ * \a last_head_region.
+ *
+ * - The graph \a sent must be a "kinda-DAG", where the only back-edges present
+ *   are self-loops.
+ * - If the result is false, \a bad_region will be updated with the smallest
+ *   region ID associated with a tail state that is still on.
+ */
+bool sentClearsTail(const NGHolder &g,
+                    const ue2::unordered_map<NFAVertex, u32> &region_map,
+                    const NGHolder &sent, u32 last_head_region,
+                    u32 *bad_region);
+
+} // namespace ue2
+
+#endif // NG_SOM_UTIL_H